38997683 Methyl Tertiary Butyl Ether MTBE Full Report

369
PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR MEMBER OF GROUP AND SUPERVISORS 1

Transcript of 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

Page 1: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

MEMBER OF GROUP AND SUPERVISORS

1

Page 2: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

ACKNOWLEDGEMENT

First and foremost, thank you to Allah S.W.T for giving us the strength to finish up this

project report. Without Your Willingness we would not be able to complete this project.

It would be impossible to acknowledge adequately all the people who have been

influential, directly or indirectly in forming this project.

We would like to take this opportunity to express our deepest gratitude to our

supervisors, Encik Mohd Imran Bin Zainuddin and Puan Sunita Binti Jobli who has

given us his constant encouragement constructive advises and his patient in

monitoring our progress in this project.

Our appreciation and special thanks goes, Puan Hasnora Binti Jafri, Puan Junaidah

Binti Jai, Encik Aziz Bin Ishak for supplying the valuable information and guidance for

this project.

We greatly indebted to Encik Napis Bin Sudin for his cooperation and willingness to be

interviewed and for provide us with invaluable information and for his resourcefulness

in gathering material.

Special thanks owe to Puan Masni Bt Ahmad for her willingness to be interviewed and

for the painstaking care she has shown in assisting us throughout the project.

We also would like to express our appreciation to the Malaysia Industrial Development

Authority (MIDA), Pusat Informasi Sirim Berhad, Petronas Resource Center, Jabatan

Perangkaan Malaysia and Tiram Kimia Sdn.Bhd. (Kuala Lumpur) for their generous

supply of relevant documents and material needed research.

Last but not least to all my lecturers, family, friends and collegues for their

encouragement and kind support when we need it most.

2

Page 3: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

ABSTRACT

The purpose for this MTBE or Methyl tertiary Butyl Ether plant is to produce 300,000

metric tonne/year. MTBE is the simplest and most cost effective oxygenate to produce,

transport and deliver to customers. The additive works by changing the oxygenate /

fuel ratio so that gasoline burns cleaner, reducing exhaust emissions of carbon

monoxide, hydrocarbons, oxides of nitrogen, fine particulates and toxic. Two units will

be considered which are the fluidizations, (Snamprogetti) Unit and the Etherification

Unit. The raw materials used are isobutane, methanol, and water as feedstock. In

addition, two types of catalysts are chromia alumina catalyzed compound in

Snamprogetti Unit, while sulphonic ion exchanged resin catalyzed is used in the MTBE

reactor. A good deal of catalyst has been devoted to improve the activity, selectivity,

and the lifetime of the catalysts.

In the Design Project 2, we emphasize in the individual chemical and mechanical

designs for selected equipments in the plant. The chosen equipments are Catalytic

Cracking Reactor, Multitubular Fixed Bed Reactor, MTBE Distillation Column, Liquid-

Liquid Extraction Column and Heat Exchanger.

Design Project 2 also includes Process Control, Safety, Economic Evaluation, Process

Integration and as well as Waste Treatment, which are considered as group works.

3

Page 4: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CONTENTS

TITLE PAGE

DECLARATION II

CERTIFICATION III

ACKNOWLEDGEMENT V

ABSTRACT VI

LIST OF TABLES

LIST OF FIGURES

LIST OF NOMENCLATURES

REPORT 1

CHAPTER 1 PROCESS BACKGROUND AND INTRODUCTION

1.1 Introduction 11.2 Historical Review of MTBE Production Process 2

1.2.1 UOP Oleflex Process 31.2.2 Philips Star Process 31.2.3 ABB Lummus Catofin Process 31.2.4 Snmprogetti Yartsingtez FBD Process 4

CHAPTER 2 PROCESS SELECTION

2.1 Method Consioderation 52.2 Detailed Process Description 7

2.2.1 Snaprogetti Yarsingtez fbd Process 72.2.2 MTBE Unit 82.2.3 Distillation Column Unit 82.2.4 Liquid-Liquid Extraction Unit 9

CHAPTER 3 ECONOMIC SURVEY

3.1 Market Survey 103.1.1 World Market 10

3.2 Asia Market 113.3 Demand 113.4 Production Capacity 14

4

Page 5: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.5 Supply 143.6 Market Price 15

3.6.1 Methanol 153.6.2 Isobutane 163.6.3 Catalyst 163.6.4 Conclusion 16

3.7 Economic Analysis 173.7.1 Break Even Analysis 173.7.2 Data Calculation1 20

CHAPTER 4 PLANT LOCATIONS & SITE SELECTION

4.1 Plant Location 244.2 General Consideration On the site Selection 24

4.2.1 Location with Respect To Marketing Area 254.2.2 Raw Material supply 254.2.3 Transport Facilities 254.2.4 Availability Of Labor 254.2.5 Availability Of Utilities 264.2.6 Environmental Impact and Effluent Disposal 264.2.7 Local Community Considerations 264.2.8 Land (Site Consideration) 264.2.9 Political and Strategic Consideration 27

4.3 Overview on Prospective Locations 274.3.1 Teluk Kalong 284.3.2 Tanjung Langsat 284.3.3 Bintulu 29

4.4 Conclusion 33

CHAPTER 5 ENVIRONMENTAL CONSIDERATION

5.1 Introduction 345.2 Stack gas 35

5.2.1 Gas Emission treatment 355.3 Wastewater Treatment 35

5.3.1 Wastewater characteristic 355.3.1a) Priority pollutants 365.3.1b) Organic 365.3.1c) Inorganic 375.3.1d) pH and Alkalinity 375.3.1e) Temperature 38

5.3.2 Liquid waste treatment 385.3.2a) Equalization treatment 385.3.2b) Solid waste treatment 39

5.3.3 Waste Minimization 41

5

Page 6: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 6 SAFETY CONSIDERATION

6.1 Introduction 426.2 Material Safety Data Sheet 43

6.2.1 Isobutane 436.2.1.1 Product Information 43

Physical & Chemical Properties 436.2.1.2 Immediate Health Effects 446.2.1.3 First Aid Measure 44

6.2.2 N-Butane 446.2.2.1 Handling and Storage 45

6.2.3 Methanol 456.2.4 MTBE 46

6.2.4.1 Physical State and Appearance466.2.4.2 Physical Dangers 466.2.4.3 Chemical Dangers 476.2.4.4 Inhalation Risks 47

6.2.5 TBA 476.2.5.1 Recognition 486.2.5.2 Evaluation 486.2.5.3 Controls 48

6.3 Hazard Identification & Emergency Safety & Health Risk 49

CHAPTER 7 MASS BALANCE

7.1 Snamprogetti -Yarsingtez FBD Unit 517.2 Separator 537.3 Mixer 537.4 MTBE Reactor 54

7.4.1 1st Reaction in rector 557.4.2 2nd Reaction in reactor 567.4.3 3rd Reaction in reactor 577.4.4 Overall reaction 58

7.5 Distillation Column 597.6 Liquid Extraction Column 607.7 Distillation Column 617.8 Overall reaction system; flow diagram 627.9 Scales Up Factor 63

CHAPTER 8 ENERGY BALANCES

8.1 Energy Equation 648.2 Energy balance: Sample of calculation 65

8.2.1 Pump 1 738.2.2 Cooler 1 758.2.3 Separator 768.2.4 MTBE Reactor 788.2.5 Pump 2 79

6

Page 7: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

8.2.6 Mixer 808.2.7 Expander 1 818.2.8 Cooler 1 828.2.9 Distillation Column 1 848.2.10 Cooler 2 868.2.11 Pump 3 878.2.12 Extraction Column 888.2.13 Pump 4 898.2.14 Pump 5 918.2.15 Distillation Column 2 928.2.16 Cooler 3 93

CHAPTER 9 HYSYS 95

APPENDICES

REPORT 2

CONTENTS

PAGE

CHAPTER 1 CHEMICAL DESIGN AND MECHANICAL DESIGN

SECTION 1 CATALYTIC CRACKING DESIGN

1.1 Introduction 11.2 Estimation of Cost Diameter of Reactor 31.3 Calculation of TDH Height 41.4 Minimum Fluidization Velocity 41.5 Calculation for Terminal Velocity 51.6 Find the Value Kih 81.7 Find the value Eo 91.8 Calculation of Solid Loading 101.9 Calculation for Holding Time 121.10 Calculation for Pressure Drop 141.11 Determine the Direction and Flowrate 151.12 Design of Cyclone 171.13 Calculation for Mechanical Design 21

2.2 Mechanical Design2.2.1 Introduction 582.2.2 Design stress 592.2.3 Welded Joint Efficiency 59

7

Page 8: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2.2.4 Corrosion allowance 592.2.5 Minimum thickness of cylindrical section of shell 592.2.6 Minimum thickness of domed head 602.2.7 Loading stress 612.2.7.1 Dead weight load 61

1.2.7.1 Dead Weight of Vessel 611.2.7.2 Weight of the Tubes 621.2.7.3 Weight of Insulation 621.2.7.4 Weight of Catalyst 631.2.7.5 Total Weight 631.2.7.6 Wind Loading 631.2.7.7 Analysis of Stresses 64

2.2.8 Dead Weight Stress 652.2.9 Bending Stress 652.2.10 Radial Stress 662.2.11 Check Elastic Stability 672.2.12 Vessel Support 682.2.13 Skirt Thickness 682.2.14 Height of the Skirt 692.2.15 Bending Stress at Base of the Skirt 702.2.16 Bending Stress in the Skirt 702.2.17 Base Ring and Anchor Bolt Design 712.2.18 Compensation for Opening and Branches 732.2.19 Compensation for Other Nozzles 742.2.20 Bolted Flange Joint 74

2.2.20.1 Type of Flanges Selected 742.2.20.2 Gasket 75

2.2.21 Flange face 75

SECTION 3 MTBE DISTILLATION COLUMN

3.1 Introduction 783.2 Selection f Construction Material 793.3 Chemical Design 79

3.3.1 Determine the Number of Plate 813.3.2 Determination of Number of Plate 883.3.3 Physical Properties 893.3.4 Determination of Column Diameter 893.3.5 Liquid Flow Arrangements 903.3.7 Plate Layout 913.3.8 Entrainment Evaluation 913.3.9 Weeping Rate Evaluation 943.3.13 Number of Holes 953.3.14 Column size 96

3.4 Mechanical Design3.4.1 Material construction3.4.2 Vessel Thickness 983.4.3 Heads and closure 983.4.4 Total Column Weight 99

8

Page 9: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.4.5 Wind Loads 1003.4.6 Stiffness Ring 100

3.5 Vessel Support Design 100

SECTION 4 DESIGN OF LIQUID-LIQUID EXTRACTION COLUMN

4.1 Introduction 1034.2 Chemical Design 104

4.2.1 Choice of Solvent 1044.2.2 Estimation the Physical Properties 1044.2.3 Determination the Number of Stage 1054.2.4 Sizing of Sieve Tray 1074.2.5 Number of Holes 1074.2.6 Column Parameter 1074.2.7 Weeping Evaluation 108

4.3 Mechanical Design 1104.3.1 Material Construction 1114.3.2 Vessel Thickness 1114.3.3 Design of Domed Ends 1124.3.4 Column Weight 112

4.3.4.1 Dead Weight of Vessel 1134.3.4.2 Weight of Plate 1134.3.4.3 Weight of Insulation 1134.3.4.4 Total weight 1144.3.4.5 Wind Loading 114

4.3.5 Analysis of Stress 1154.3.5. 1 Longitudinal & Circumferential Pressure Stress 1154.3.5.2 Dead weight 1154.3.5.3 Bending Stress 1154.3.5.4 Buckling 116

4.3.6 Vessel Support Design 1174.3.6.1 Skirt Support 1174.3.6.2 Base Ring and Anchor 119

4.3.7 Piping Sizing 122

SECTION 5 HEAT EXCHANGER DESIGN

5.1 Introduction 1275.1.1 Designing the heater 129

5.2 Chemical Design 1305.2.1 Physical Properties of the Stream 1305.2.2 The Calculation 1315.2.3 Number of Tubes Calculation 1335.2.4 Bundle and Shell Diameter 1345.2.5 Tube Side Coefficient 1355.2.6 Shell Side Coefficient 1375.2.7 Overall Heat Transfer Coefficient 1395.2.8 Tube Side Pressure Drop 1405.2.9 Shell Side pressure Drop 140

5.3 Mechanical Design 1425.3.1 Design Pressure 142

9

Page 10: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.3.2 Design Temperature 1425.3.3 Material of Construction 1425.3.4 Exchanger Type 1435.3.5 Minimum Thickness 1435.3.6 Longitudinal Stress 1445.3.7 Circumferential Stress 1445.3.8 Minimum Thickness of Tube wall 144 5.39 Minimum Thickness of Head and Closure 1455.3.10 Minimum Thickness of the Channel Cover 1465.3.11 Design Load 1475.3.12 Pipe Size Selection for the Nozzle 1505.3.13 Standard Flanges 1505.3.14 Design Of Saddles 1525.3.15 Baffles 152

CHAPTER 2 PROCESS CONTROL AND INSTRUMENTATION

2.1 Introduction 1542.2 Objective of control 1552.3 Control system design sheet 156

2.3.1 Heat Exchanger 1562.3.2 Catalytic cracking fluidized bed reactor 1572.3.3 Compressor 1582.3.4 Condenser 1592.3.5 Separator 1602.3.6 Fixed bed reactor 1612.3.7 Distillation Column 1622.3.8 Liquid -liquid extraction Column 1632.3.9 Distillation Column 1642.3.10 Mixer 1652.3.11 Expander 166

CHAPTER 3 SAFETY CONSIDERATION

3.1 Introduction 1673.2 Hazard and Operability Study 1683.3 Plant Start Up and Shut Down Procedure 170

3.3.1 Normal Start Up and Shut Down the Plant 1713.3.1.1 Operating Limits 1713.3.1.2 Transient Operating and Process Dynamic 1723.3.1.3 Added Materials 1723.3.1.4 Hot Standby 1723.3.1.5 Emergency Shut Down 172

3.3.2 Start up and Shut down Procedure for the main Equipment 1723.3.2.1 Reactor 1723.3.2.2 Distillation Column 1733.3.2.3 Liquid-Liquid Extraction Column 1743.3.2.4 Heat Exchanger 175

3.4 Emergency Response Plan (ERP) 175

10

Page 11: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.4.1 Emergency Response Procedures 1763.4.2 Evacuation Procedures 1763.4.3 Fires 1773.4.4 Explosion, Line Rupture or Serious Leak 1773.4.5 Other Emergencies 177

3.5 Plant Layout 178

CHAPTER 4 ECONOMIC EVALUATION

4.1 Introduction 1844.2 Cost Estimation 1874.3 Profitability Analysis 199

4.3.1 Discounted Cash flow 1994.3.2 Net Present Value 2024.3.3 Cumulative Cash flow Diagram 2034.3.4 Rate of Return 2044.3.5 Sensitivity Analysis 2054.3.6 Payback Period 206

4.4 Conclusion 208

CHAPTER 5 PROCESS INTEGRATION AND PINCH TECHNOLOGY

5.1 Introduction 2095.2 Pinch Technology 2095.3 The Problem Table Method 2105.4 The Heat Exchanger Network 2145.5 Minimum number of exchangers 216

CHAPTER 6 WASTE TREATMENT

6.1 Introduction 2206.2 Wastewater Treatment 2216.3 Wastewater Treatment Plant Design 2246.4 Sludge Treatment 2296.5 Waste Treatment Plant Layout 2306.6 Absorption tank using granular activated carbon 231

6.6.1 Analysis of the absorption process 2326.6.2 Breakthrough Absorption capacity 233

APPENDICES

11

Page 12: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

LIST OF TABLES OF DESIGN I

TABLE TITLE PAGE

1.1 The Physical and Chemical Properties of MTBE 2

2.1 The Comparison of the UOP Oleflex, Philips Star

SP-Isoether FBD Process 6

3.1 Trade Balance of MTBE in Asia and Pacific 12

3.2 MTBE Balances for Asia and Pacific 13

3.3 Production, Import, Export & Consumption in Europe in

Year 2000 14

3.4 Supplies MTBE Plant in Asia & Pacific 15

3.5 Standard Price for Isobutane 16

3.6 Cost of Producing MTBE 500000 tonne/year 18

3.7 Value in US Dollar Converted to RM 20

3.8 Value in US Dollar Converted to RM per tonne 20

3.9 Data Calculation by using Microsoft Excel in RM 23

4.1 The Comparison of the Potential Site Location 30

4.2 The Comparison of Location in term of Weightage Study 31

4.3 The Electricity Tariffs (Industrial Tariff) for Peninsular

Malaysia and Sarawak 33

12

Page 13: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

LIST OF TABLES OF DESIGN II

TABLE TITLE PAGE

Chapter 1

Section 1

1.1 Calculation for Terminal Velocity in Different Size of dp. 8

1.2 Correlation of Three Investigators 10

1.3 Data Calculation to Find Solid Loading 12

1.4 Summary of Mechanical Design 40

Section 3

3.1 The Composition in Feed Stream 80

3.2 The Composition in Top Stream 80

3.3 The Composition in Bottom Stream 80

3.4 The Average Relative Volatility, α 82

3.5 The Non-key Flow of the Top Stream 82

3.6 The Non-key Flow of the Bottom Stream 83

3.7 MTBE Equilibrium Curve 85

3.8 Provisional Plate Design Specification 97

3.9 Summarized Results of Mechanical Design 101

3.10 Design Specification of the Support Skirt 102

Section 4

4.1 Provisional Plate Design Specification 106

4.2 Summary of the Mechanical Design 118

4.3 Stress Analysis for Liquid-Liquid Extraction Column 119

4.4 Design Specification of the Support Skirt 119

4.5 Piping Sizing for Liquid-liquid Extraction Column 120

Section 5

5.1 Properties of Raw Material (Isobutane and N-butane)

and Steam for (E100) 130

5.2 Summary of Chemical Design For

Heat Exchanger In Series 141

5.3 By taking D = 100 mm, the selected tube nozzle 149

13

Page 14: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

TABLE TITLE PAGE

5.4 By taking D = 500 mm, the selected tube nozzle is: 149

5.5 Standard Flange for Inlet isobutene 150

5.6 Standard Flange for Outlet isobutene 151

5.7 Standard Flange for Inlet Steam 151

5.8 Standard Flange for Outlet Steam 151

5.9 Using Ds = 600mm, the Standard Steel Saddles

for Vessels up to 1.2m 152

5.10 Summary of Mechanical Design For

Heat Exchanger in Series 153

Chapter 2

2.1 Parameter at Heat Exchanger 151

2.2 Parameter at Catalytic Cracking Fluidized Bed Reactor 152

2.3 Parameter at Compressor 153

2.4 Parameter at Condenser 154

2.5 Parameter at Separator 154

2.6 Parameter at Fixed Bed Reactor 155

2.7 Parameter at MTBE Distillation Column 156

2.8 Parameter at Liquid-liquid Extraction Column 157

2.9 Parameter at Distillation Column 158

2.10 Parameter at Mixer 159

2.11 Parameter for Expander 160

Chapter 3

3.1 Important Features in a HAZOP Study 170

Chapter 4

4.1 Labor Cost 189

4.2 Estimation Cost of Purchase Equipment 197-198

4.3 Annual Cash flow Before Tax 200

4.4 Annual Cash flow After Tax 201

4.5 Present Worth Value 202

14

Page 15: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.6 After Tax Cumulative Cash Flow 203

TABLE TITLE PAGE

4.7 Present Value (RM) When i = 30% & i = 40% 204

4.8 Future Value (RM) When MARR = 15% 205

4.9 Simple Payback Period 206

4.10 The Interpolation Simple Payback Period 206

4.11 Discounted Payback Period 207

4.12 The Interpolation Discounted Payback Period 207

Chapter 5

5.1 Shows the process data for each stream. 210

5.2 Interval Temperature for ΔTmin = 10oC 211

5.3 Ranked order of interval temperature 212

5.4 Problem Table 213

Chapter 6

6.1 Parameter Limits for Wastewater and Effluent under the Environmental Quality

Act 1974 208

6.2 Functions of Pumps in the Waste Treatment Plant 215

15

Page 16: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

LIST OF FIGURES OF DESIGN I

FIGURE TITLE PAGE

3.1 MTBE’s Role in US Gasoline grew rapidly

Through 1995 10

3.2 World MTBE Demand (1998-2010) – Mod Scenario 11

3.3 MTBE supply & Demand Asia and Pacific 13

3.4 Breakeven Analysis Chart Calculated by using Excel 19

5.1 Functional Elements in a Solid-Waste Treatment System 40.

16

Page 17: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

LIST OF FIGURES OF DESIGN II

FIGURE TITLE PAGE

Chapter 1

Section 1

1.1 Illustration Diagram of the Reactor 2

1.2 CDRe2 and CD/Re vs. Reynolds Number 6

Section 2

2.1 Analysis of Stresses 67

Section 3

3.1 MTBE Distillation Column 78

3.2 McCabe-Thiele Diagram 86

Section 5

5.1 Heat Exchanger in Series for the Heating Process 129

5.2 Steel Pipe Nozzle 149

5.3 Standard Flange 150

Chapter 2

2.1 Control Scheme for the Heat Exchanger 156

2.2 Control Scheme for Catalytic Cracking

Fluidized Bed Reactor 157

2.3 Control Scheme for the Compressor 158

2.4 Control Scheme for the Condenser 159

2.5 Control Scheme for the Separator 160

2.6 Control Scheme for the Fixed Bed Reactor 161

2.7 Control Scheme for the MTBE Distillation Column 162

2.8 Control Scheme for the Liquid-liquid Extraction Column 163

2.9 Control Scheme for the Distillation Column 164

2.10 Control Scheme for the Mixer 165

2.11 Control Scheme for the Expander 166

17

Page 18: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

FIGURE TITLE PAGE

Chapter 3

3.1 Methyl tert-Butyl Ether (MTBE) Plant Layout 180

3.2 Methyl tert-Butyl Ether (MTBE) Plant Evacuation Routes 181

3.3 PID before HAZOP 182

3.4 PID after HAZOP 183

Chapter 4

4.1 Cumulative Cash Flow (RM) Versus Year 203

Chapter 5

5.1 Diagrammatically representation of process stream 210

5.2 Intervals and streams 211

5.3 Heat Cascade 212

5.4 Grid for 4 stream problem 213

5.5 Grid for 4 Stream Problem 214

5.6 Proposed Heat Exchanger Network 216

Chapter6

6.1 The Sludge Treatment System 229

6.2 Waste Treatment Plant Layout 231

18

Page 19: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Ar - Archimedes number

a - acceleration

B - settling chamber longitudinal cross-sectional area

b - dimension

C - constant

CD - drag coefficient

c - concentration

D - system diameter

d - particle diameter

de - effective fiber diameter

E, - field intensity

F - cross-sectional area

Pr - Fronde number

g - gravitational acceleration

H - height

K - precipitation constant ,

A - Cross sectional area of catalytic reactor

orA - Area of orifice

AgC - Concentration of gas reactant

DC - Drag coefficient

Bvd - Diameter of bubble in the bed

dp - Particle diameter

D - Diffusivity

tD - Diameter of catalytic reactor

e - Thickness

E - Activation energy

19

Page 20: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

FBo - Mass flow of coal to the catalytic reactor

FC - Fixed carbon mass fraction

Hbed - Height of bed

Hh - Height of Catalytic reactor

J - Joint factor

k” - Reaction rate constant

k - Reaction rate constant

eqK - Equilibrium constant

L - Height above the bed

n - Total no of orifice

N - No of holes in 1 m2 area

Nor - No of orifice in 1 m2 area

OHCO PP2, - Partial pressure

Pi - Design stress

rC , rS - Rate of reaction

R - Ideal gas constant

Ret - Reynolds number

Rp - Radius of particle

t - Total holding time

T - Temperature

Uo - Superficial gas velocity

Umf - Minimum fluidization velocity

tU - Terminal velocity

VBed - Volume of bed

WBed - Weight of coal in bed

WC - Total mass of carbon

X - Conversion factor

α - Fitting parameter (for this design is 0.21)

β - Fitting parameter (for this design is 0.66)

gρ - Gas density

Bρ - Molar density

sρ - Bulk density of catalyst

pρ - Particle density

20

Page 21: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

gµ - Gas viscosity

τ - Time for complete conversion of reactant particle

p∆ - Pressure drop

E - total elutriation rate of particles

Ef - frictional force of particles

Ei - entrainment rate of panicle size i

Ei∞ - elutriation rate of particle size i

Eo - total entrainment rate at bed surface

E∞ - total elutriation rate of particles

g - gravitational acceleration constant

gc - gravitational conversion constant, m kg/s2 kg -force

Gi - solids flow rate

h - height above dense bed surface

Rep - particle Reynolds Number = ( ) µρ /ptsog dUU −

Ret - µρ /gdpU

t - time

Umf - minimum fluidization velocity

Uo - superficial gas velocity

Usi - solid velocity (upward)

Us - single particle terminal velocity of particle size i

W - weight fraction of bed

Ws - weight of solid particles in verlical pipe having length h

Xi - weight fraction of particle size i in bed

Greek Symbols

ε - voidage in freeboard

21

Page 22: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

iε - voidage in freeboard for system having only particle size i

λ - solid friciion coefficient

gρ - gas density

pρ - particle density

22

Page 23: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 1

PROCESS BACKGROUND AND INTRODUCTION

1.1 INTRODUCTION

Methyl tertiary butyl ether (MTBE) is produced by reacting isobutene with methanol

over a catalyst bed in the liquid phase under mild temperature and pressure. Isobutene

can be obtained from stream cracker raffinate or by the dehydrogenation of isobutane

from refineries. Ether in general is a compound containing an oxygen atom bonded to

two carbon atoms.

In MTBE one carbon atom is that of a methyl group – CH3 and the other is the central

atom of a tertiary butyl group, -C (CH3)). At room temperature, MTBE is a volatile,

flammable, colorless liquid with a distinctive odour. It is miscible with water but at high

concentrations it will form an air-vapour explosive mixture above the water, which can

ignite by sparks or contact with hot surfaces.

MTBE has good blending properties and about 95% of its output is used in gasoline as

an octane booster and an oxygenate (providing oxygen for cleaner combustion and

reduced carbon monoxide emissions). It is also used to produce pure isobutene from

C4 streams by reversing its formation reaction. It is a good solvent and extractant.

Table 1.1: The Physical and chemical properties of MTBE

23

Page 24: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Chemical formula C5H12OMolecular structure (CH3)4CO

Oxygen content 18.2 wt%Physical state (at normal

temperature and pressure)

Colorless liquid

Boiling point 55.2oCMelting point -108.6 oCFlash point 30 oC

Autoignition temperature 425 oCFlammable limits in air 1.5 – 8.5%

Relative density 0.7405g/ml at 20 oCVapour pressure 245 mm Hg at 25 oCReactive index 1.3690 at oC

Color ColorlessWater solubility 42000mg/l at 25 oC (<10% in

water, miscible with ethanol and

diethyl ether)Partition coefficient n-

octanol/water (log10)

1.06

Henry’s Law Constant 65.4 Pa/m3/mol

1.2 HISTORICAL REVIEW OF MTBE PRODUCTION PROCESS

The MTBE plants actually consist of six units: Isomerization Unit (including

deisobutanizer), Dehydrogenation Unit, MTBE Unit, Methanol Recovery Unit,

Oxygenate Removal Unit and Olefin Saturation Unit. A common offsite utility system

will be incorporated to distribute the required utilities to each unit. There are four

method of producing MTBE implemented under license as the following:

1. UOP-Oleflex Process

2. Phillips STAR Process

3. ABB Lummus Catofin Process

4. Snamprogetti-Yarsingtez FBD (SP-Isoether) Process.

1.2.1 UOP-Oleflex Process

24

Page 25: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The UOP-Oleflex process uses multiple side-by-side, radial flow, moving-bed reactors

connected in series. Preheated feed and interstage heaters supply the heat of reaction.

The reaction is carried out over platinum supported on alumina, under near isothermal

conditions. The catalyst system employs UOP's Continuous Catalyst Regeneration

(CCR) technology. The bed of catalyst slowly flows concurrently with the reactants and

is removed from the last reactor and regenerated in a separate section. The

reconditioned catalyst is then returned to the top of the first reactor. The typical

processes involved are the deisobutenization, the isomerisation and the

dehydrogenation process that has been commercial in Malaysia.

1.2.2 Philips Star Process

The second one is the Philips Steam Active Reforming (STAR) Process. The Phillips

Steam Active Reforming (STAR) Process uses a noble metal-promoted zinc aluminate

spinel catalyst in a fixed-bed reactor. The reaction is carried out with steam in tubes

that are packed with catalyst and located in a furnace. The catalyst is a solid,

particulate noble metal. Steam is added to the hydrocarbon feed to provide heat to the

endothermic reaction, to suppress coke formation, and to increase the equilibrium

conversion by lowering partial pressures of hydrogen and propane.

1.2.3 ABB Lummus Catofin Process

The ABB Lummus Catofin Process uses a relatively inexpensive and durable

chromium oxide–alumina as catalyst. This catalyst can be easily and rapidly

regenerated under severe conditions without loss in activity. Dehydrogenation is

carried out in the gas phase over fixed beds. Because the catalyst cokes up rapidly,

five reactors are typically used. Two are on stream, while two are being regenerated

and one is being purged. The reactors are cycled between the reaction and the

reheat/regeneration modes, and the thermal inertia of the catalyst controls the cycle

time, which is typically less than 10 minutes. The chromium catalyst is reduced from

Cr6+ to Cr3+ during the dehydrogenation cycle. The raw materials used to produce

MTBE by using this method are butanes, hydrogen and as well as recycled isobutene

from the system itself. In this process, there is an isostripper column, which separates

the heavies, and the light ends from which then could produce MTBE.

25

Page 26: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

1.2.4 Snamprogetti-Yartsingtez FBD (SP-Isoether)

The Snamprogetti-Yarsingtez SP-Isoether (FBD) Process uses a chromium catalyst in

equipment, which is the fluidized bed that resembles conventional fluidized catalytic

cracking technology used in the oil refinery. The catalyst is recirculated from the

reactor to the regeneration section on a 30–60-min cycle. The process operates under

low pressure and has a low-pressure drop and uniform temperature profile.

Snamprogetti has been presenting and marketing their hydrogenation technology,

ISOETHER 100, since 1997. This process is to be used to convert MTBE units by

utilizing Snamprogetti’s MTBE Water Cooled Tubular Reactor Technology. In this SP-

Isoether Process, the products are MTBE and isooctagenas (iso octane gas). In this

SP-Isoether Process the catalyst used in the isoetherification reactor is the same as

those other typical processes, which is Platinum. (Please refer Appendix A – Figure

1.3).

Four method processes of the MTBE above are favorable among the

petrochemical firms.

CHAPTER 2

PROCESS SELECTION

26

Page 27: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Suitable process, which is gives a lot of profit and less problem is an important in order

to determinant for the success of a plant. This chapter will briefly discuss the best

process selected based on a few criteria. It covers general consideration, detailed

consideration for process selection and conclusion on the process selection.

2.1 METHOD CONSIDERATION.

From the processes mentioned earlier, there are many ways to produce MTBE. It is

essential to choose the best method that will be used to produce MTBE. The selection

of the method must consider the safety of the plant, minimum waste or by product

generated, efficient and economical. Snamprogetti-Yarsingtez SP- Isoether FBD

process will be chosen as the method to produce MTBE. More detailed reasons for the

selection of this process are: High conversion (greater than 98 %) with few by-products

compared to other process. From the economy aspect,Snamprogetti-Yarsingtez FBD

Process can reduce the cost of setting up the plant as it can be implied in any of typical

MTBE-produced plant, known as “Financial Safety Net”.(When an MTBE plant faces an

oversupplied MTBE market, Isoether makes it possible to switch production from

MTBE to a superior Alkylate.). As for the safety aspects of the plant, as the

Snamprogetti-Yarsingtez FBD is a safe process as it just use the fluidize bed to the

process of producing MTBE. The process operates under low pressure and has a low-

pressure drop and this means that the fluidized bed is physically not harmful to anyone.

As for the temperature, it operates under uniform temperature profile. As the

temperature is not high, this means that the process is not as dangerous as other high-

temperature-operated process. But, precautions should be taken seriously all the time,

as we do not know when an accident could happen even in the safest place. As for the

waste by using the Snamprogetti-Yarsingtez FBD Process, the product of the process

is only MTBE and other effluent and as well as flue gas which are not harmful to the

environment.

Table 1.1 The comparison of the UOP-Oleflex, Philips Star, ABB Lummus Catofin and

Snamprogetti- Yartsingtez SP-Isoether FBD process.

27

Page 28: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Method and

Consideration

UOP-Oleflex

Process

STAR Philip

process

ABB Lummus

Process

Snamprogetti-

Yarsingtez FBD

process

Economic

Consideration

Investment cost

is very modest

Investment cost

were evaluated

for 700 BPSD

(650tonne/day)

feed capacity

Lower capital

investment

Reduce the cost

of setting up the

plant as it can be

implied in any of

typical MTBE-

produced Efficiency

(Isobutylene

Selectivity)

97-99% 98% 99 .99% Greater than 98%

Advantages 1. Higher per

pass

conversion and

at least 1-2%

higher catalyst

selectivity as a

result of lowest

operating

pressure and

temperature.

2. No catalyst

losses.

1. The Stabilized

Product Is Near

Equilibrium

Mixture Of

Isobutane.

2.The Light-End

Yield Fr. Cracker

Is Less Than 1

Wt% Butane

Feed

1.CD Tech

Efficiently Uses

The Heat

Released By An

Exothermic

Reaction.

2.Conducting 2

Unit Operations

In 1 Equipment

1.Environmental

Friendly

2.”Financial

Safety Net”.

(When an MTBE

plant faces an

oversupplied

MTBE market,

Isoether makes it

possible to switch

production from

MTBE to a

superior Alkylate.)

Disadvantages 1. Less

efficiencies

1. Much heat is

needed as

furnace is used.

1. The Reaction

Must Take Place

In The Liquid

Phase –Catalyst

Must Remain

Completely

Wetted.

2.The Reaction

Cannot Be Overly

1. Not widely

practiced in

industry, as it

needs thorough

research to

implement it.

28

Page 29: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Endothermic

2.2.1 DETAILED PROCESS DESCRIPTION

2.2.2 Snamprogetti-Yartsingtez SP-Isoether (FBD) Process

The Snamprogetti-Yarsingtez SP-Isoether (FBD) Process uses a chromium catalyst in

equipment, which is the fluidized bed that resembles conventional fluidized catalytic

cracking technology used in the oil refinery with 65% isobutane (i-C4H10) conversion to

produce isobutene.

Dehydrogenation reaction that occur in this process:

iC4H10 iC4H8 + H2

The main feature of this process is that the catalyst filled annuli are connected in such a way

that small, discrete amounts of catalyst can be withdrawn from the bottom of a reactor,

and sent to the top of the reactor. Catalyst withdrawn from the bottom of the reactor is

sent to a separate regeneration section for regeneration prior to being sent to the top of

the reactor. The catalyst is recirculated from the reactor to the regeneration section on

a 30–60-min cycle. The reactor and regeneration sections are totally independent of

each other. The regeneration section can be stopped, even for several days, without

interrupting the dehydrogenation process in the reactor section. The vaporized

isobutane is fed along with fresh catalyst to the first, called reactor, and the spent

catalyst is separated from the products and sent to the regenerator, where air (O2) is

added to oxidize the carbon. The reactor cracks the isobutane and forms coke on the

catalyst. Then in the regenerator the coke is burned off and the catalyst is sent back

into the reactor. The “magic” of this process is that the reactor-regenerator combination

solves both the heat management and coking problems simultaneously. Burning off the

coke is strongly exothermic, and this reaction in the regenerator supplies the heat

(carried with the hot regenerated catalyst particles) for the endothermic cracking

reactions in the reactor.

The process operates under low pressure and has a low-pressure drop and

uniform temperature profile. Products that have been produced from this unit are

29

Page 30: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

isobutene. Isobutene available in the C4 stream from the Snamprogetti-Yarsintez FBD

unit will be combining with methanol, which is sourced from the Sabah Gas Industries

methanol plant in Labuan to produce, fuel-grade MTBE with a high-octane value in the

MTBE unit.

2.2.3 MTBE Unit

The MTBE unit includes two sections such as the main reaction section and the

finishing reaction. In the main reaction section, 98% conversions of isobutene occurs

mainly in the main reactor which are designed to provide the mechanical ands thermal

conditions required by the expanded catalyst bid technology.

Reactions occur in this unit are:

1. iC4H8 (isobutene) + CH3OH (methanol) C5H12O (MTBE)

2. CH3OH + CH3OH (CH3)2O + H2O (DME)

3. iC4H8 + H2O C4H10O (TBA)

The reactor is operated in an up-flow direction with an external liquid recycle to

remove the heat of reaction and to control the expansion of the catalyst bed. This

selective reaction of methanol with isobutene is conducted in liquid phase at moderate

temperature on an ion exchange resin type catalyst. The expansion of the catalyst bed

in the reactor is ensured by pump around circulation loop with a cooling water cooler to

control the reactor feed temperature to remove the heat of reaction. Resin traps on top

of each reactor to trap resin in case of carryover with the liquid. In the finishing reactor

section, isobutene final conversion is achieved in a catalytic column where reaction

and distillation are performed simultaneously.

2.2.4 Distillation Column Unit

30

Page 31: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

This column includes a separation column yielding MTBE product at the bottom and

(isobutene, isobutene, normal butane, water and DME) with methanol entrained by

azeotropy at the top. The reaction section bed is contained in the upper part of this

column. An excess of methanol is maintained corresponding to the amount leaving the

tower in the azeotrope. The required methanol is passed through guard beds and

filtered prior to being charged to the catalytic column to achieve final conversion.

Bottom MTBE product and the other by-product such as TBA, DME is sent to rundown

tanks under level control after cooling in feed/bottom exchanger and trim cooler.

The overhead of the column is condensed in the air-cooled condenser under

pressure control. One part of the liquid is sent to the column as reflux and the other

part to the liquid-liquid extraction unit after cooling.

2.2.5 Liquid-Liquid Extraction Unit

In this unit methanol will extract from the isobutene, isobutene, normal butane to

produce C4 raffinate from the overhead of the column and at the bottom, methanol and

water are produced. C4 raffinate from this unit we decided to sell to the Korea.

CHAPTER 3

ECONOMIC SURVEY

31

Page 32: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.1 MARKET SURVEY

3.1.1 World Market

The MTBE market has been in strong continuous growth since 1992. For instance, the

1998 world consumption was approximately 19.5 million tonnes, about double that of

1992, representing an annual growth rate of about 12%. Present trends indicate a mild

growth in 2000, up to 20 million tonnes, with US consumption slightly declining and

other parts of the world growing (EEA 2000). The MTBE’s role in U.S. gasoline grew

rapidly through 1995 given away in figure 3.1.

Figure 3.1 MTBE’s role in U.S. gasoline grew rapidly through 1995 (Sources: Local Issues, Global Implications)

3.2 ASIA MARKET

Most Asia countries such as South Korea, Japan, Hong Kong, Taiwan, China, Malaysia,

Singapore, Philippines and Thailand, have already phased lead out of their gasoline pool

and are replacing it with oxygenates such as MTBE. Due to MTBE’s relative ease in

blending into gasoline, easy transportation and storage, as well as relatively cheap and

abundant supply, MTBE is the most widly use oxygenate in Asia.

However, the use of MTBE in gasoline blending is not mandatory for countries

like South Korea and Thailand. South Korea, for instance, requires a 1.3% - 2.3%

32

Page 33: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

oxygenate content in gasoline during the winter, compared to a minimum of 0.5% for

the summer. In other Asian Countries, MTBE is mainly use as an octane booster to

replace lead. (source: features mtbe asias.html).

3.3 DEMAND

World demand of MTBE mod scenario is about 4.1 mil ton per annum consumption in

US West Coast at stake due to the legislation from 1998 to 2010. It has as an impact

on 80% of PETRONAS MTBE exports to the US. This mod scenario is representing in

figure 3.2.

Figure 3.2: World MTBE demand (1998-2010) – mod scenario(Sources: Petronas’s Library Kuala Lumpur City Center (KLCC)

U.S. demand is about 250,000b/d, dominates MTBE consumption. Most MTBE

is used to comply with mandated oxygen content rules for gasoline supplied to either

RFG or wintertime carbon monoxide areas. A small amount may be utilized for octane

enhancement.

In Europe, MTBE demand is estimated about 60,000 b/d. MTBE use in Europe

is essentially confined to Octane enhancement, and about 6,000 b/d is exported to the

United States. Eastern Europe currently consumed about 10,000 b/d of MTBE.

In Asia, demand for MTBE in this region is expected to grow at much more

rapid rate than elsewhere in the world. The rate will taper off late in decade from about

12% per year to about 8% by the turn of the century, since the early rapid growth has

33

Page 34: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

been fed by the lead phase down which should be nearly complete by 2000. Throughout

the period, the region will be a net importer of MTBE, mostly obtained from the Middle

East. The trade balance of MTBE in Asia and Pacific is expected to be in table 3.1.

(Sources: MTBE annual Report)

Table 3.1 Trade Balance of MTBE in Asia and Pacific

(Sources: MTBE annual Report)

Capacities listed are the average available during the year. Details for 1995 and 1999

of MTBE Balance for Asia and Pacific are shown in table 3.2. These data are also

shown graphically in figure 3.3 which indicate for MTBE supply and demand Asia and

Pacific. (Sources: MTBE annual Report)

Table 3.2: MTBE Balance for Asia and Pacific(Sources: MTBE annual Report)

34

Page 35: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

MTBE supply and demand

Asia and Pacific

Figure 3.3: MTBE supply and demand Asia and Pacific

(Sources: MTBE annual Report)

Demand for MTBE expected to be marginally firmer in the near future as Asian

Countries such as Indonesia and India are working totally phase out lead from their

gasoline pool. Supply on other hand is expected to remain abundant, as Asia is able to

produce about 3 million Mt/yr of MTBE for its Captive consumption. In addition to this,

Asia attracts a regular supply of about 500,000 ton/yr of MTBE from Middle Eastern

and Europe sources.(Reference: features mtbe asias.html).

35

Page 36: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.4 PRODUCTION CAPACITY

Commercial production of MTBE started in Europe in 1973 and in the US in 1979. Total

worldwide production capacity in 1998 was 23.5 million tones and the actual production

was 18 million tones

The annual production volume of MTBE in the year 2000 in the Europe was

2,844,000 tons. About 129,000 tonnes was imported and about 479 000 tonnes were

exported outside the Europe in the year 2000 ((Dewitt & Company Inc. 2002). The

majority of the exported volume (> 83%) was exported to USA and Canada. The

majority of exported volume (> 80%) was transported as non-blended MTBE and

minority as a component of petrol (blended). The annual consumption of MTBE within

the Europe was hence 2,495,000 tons in the year 2000 (see table below). For the future

no substantial increase in MTBE usage is expected. (Dewitt & Company Inc. 2002).

Table 3.3: Production, import, export and consumption in Europe in year 2000

(tonnes/year) souces: (Dewitt & Company Inc. 2002).

Production Import into Europe Export outside Europe Consumption2 844 000 129 000 479 000 2 495 000

The world's MTBE industry today is operating at about 80% of capacity. The US

is by far the largest market, having about 43% of the production capacity but

consuming 63% of total global output. On stability, the Middle East is the swing

producer, exporting more than 50,000 bbl/day to the US and elsewhere.

3.5 SUPPLY

DeWitt’s Company estimates for local production of MTBE a summarized in table 3.4.

Most of plants unit are refinery-based units taking isobutylene from FCCU units, or as

Raffinate I from olefins plants. Since olefin plants in the region a mostly naphtha-

based, they produce significant quantities of C4 olefins for this purpose. There is one

butane-based plant in Malaysia. Table 3.4 also shown for MTBE plants suppliers to

Asia and Pacific.

36

Page 37: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 3.4 Suppliers MTBE plant in Asia and Pacific

(Sources: MTBE annual Report)

3.6 MARKET PRICE 3.6.1 Methanol Price of methanol, as feedstock in Asia is $240 - $280 /ton. While in Europe, the prices

is $265 - $270 / ton free on board (fob) Rotterdam. In U.S. the price of methanol is 76

cts – 77cts/ gal in fob.

Global Methanol demand is expected to increase to 3.5 % per year over the

next 5 years, compared to 1.0% - 1.5% growth in 2002 and 2003. Those lower growth

rates are attributable to the phase-out of Methyl tert-butyl ether (MTBE) as oxygenate

in gasoline in California, and slower economic growth in China caused by SARS.

Methanol growth in China is forecast at 7% - 8.5% per year, fueled by formaldehyde

and acetic acid demand. (Chemicals Week)

3.6.2 Isobutane

Standard price for isobutene is stated by followed:

37

Page 38: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 3.5 : Standard price for isobutane

Grade Purity Cylinder SizeVolume

lbsPrice per Cylinder

Grade 4.0 99.99%

LP30 117 RM900.00

LP15 60 RM600.00

LP05 23 RM370.00

LP01 6 RM200.00

Grade 3.0 99.9%

1/2 Ton 490 RM1225.00

LP30 117 RM380.00

LP15 60 RM240.00

LP05 23 RM170.00

LP01 6 RM100.00

Instrument 99.5%

1 Ton 490 RM890.00

LP30 117 RM293.00

LP15 60 RM185.00

LP05 23 RM100.00

LP01 6 RM75.00

3.6.3 Catalyst

Price of Chromia catalyst Compound – USD60 000/Rottedam (Rdam) from the existing

plant. (En Mohd. Napis, from MTBE plant, Gebeng )

3.6.4 Conclusion

Our company will import the methanol and isobutane as feedstock, from Petronas

Malaysia and United State (US) respectively. Methanol feedstock will be supplied from

Gurun, Kedah production capacity of 66,000 ton/year. For the second feedstock,

isobutane (instrument grade) will be supplied by Chevron Phillips Chemical Company

LP, 10001 Six Pines Drive, The Woodlands, Texas, US by shipping method.

MTBE is suitable as a gasoline additive which simultaneously increases the

octane rating of the fuel and adds oxygen which promotes cleaner burning. When used

in place of lead-based octane enhancers, dual environmental benefits are realized, a

reduction in atmospheric lead concentrations and reduced emissions of carbon

monoxide and other smog forming chemicals. Since the 1970s, the worldwide

38

Page 39: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

consumption of MTBE has increased significantly and many new facilities have been

constructed to support the growing market (Kirschner, 1996; Riddle, 1996).

MTBE production will increase in future in Asia, Asia Pacific, Middle East and

Europe even though MTBE is banned in California but not in the entire nation of the

United States.

3.7 ECONOMIC ANALYSIS

An economic analysis used to smooth the progress of based on existing plant. This

analysis is important to ensure that the chemical plants converge and the economics is

satisfactory before the plant operate. All the data taken from MTBE Annual 1994,

DeWitt & Company Incorporated, 16800 Greenpoint Park, Suite 120 N, Houston,

Texas, that given by Petronas Library, KLCC.

3.7.1 Break-Even Analysis

When chemical engineers determine outlay for any type commercial process, they

want these costs to be enough accuracy to provide reliable decision. To accomplish

this, they must have a complete understanding of the many factors that can affect

costs. Break-even analysis is important to ensure that the plant can give profit before

the plant can run.

The objective of break even analysis is to find the point, in dollars or in ringgits

and units, at which costs equal revenues. This point is the break even point. Break

even analysis requires an estimation of fixed costs, variable costs and revenue.

Fixed costs are costs that continue even if no units are produced. Examples

include depreciation, taxes, debt, and mortgage payments. Variable costs are those

that vary with the volume units produced. The major components of variable costs are

labor and materials. However, others cost, such as the portion of the utilities that varies

with volume, are also variable cost. The different between selling price and variable

cost is contribution. Only when total contribution exceeds total fixed cost will there be

profit.

39

Page 40: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Another element in break-even analysis is the revenue function. From the

graph, revenue begins at the origin and proceeds upward to the right, increasing by

selling price of each unit. Where the revenue function crosses the total cost line (the

sum of fixed and variable costs), is the break even point, with a profit corridor to the

right and a loss corridors to the left.

Table 3.6: Cost of producing MTBE 500,000 ton/year

(Sources: DeWitt & Company Incorporated, Annual Report)

Table 3.6 showed that the cost of production of MTBE based on existing plant

producing 500,000 ton/year. From table 3.6, given data, break-even analysis can be

calculated to know the break-even point figure. Figure below indicate that break-even

chart, where it has been calculated by using excel that shown in table 3.8 and based

on the data given from table 3.6.

40

Page 41: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 3.4 : Break even analysis chart calculated by using excel.

From the break even chart figure above, the value of break-even point at the

existing capacity of 500,000 ton/year is 185,629.85 tons in units and RM

244,679,817.14 in Ringgit Malaysia (RM). This value indicates the minimum units and

values needed to be sold. The given capacity of 500,000 tons/year can give profit to

the company. The margin of safety (MOS) calculated from the graph, which is

314,370.15 tons and RM414,373,182.86. Margin of safety (MOS) in percentage of

sales is 62.87%. The sale is allowed to drop about 62.87% before the company will

incurred a loss.

In other word, at selling 300,000 tons/year capacity will also give profit to our

company. The margin of safety from the graph for 300,000 ton/year calculated is

114,370.15 tons and RM150,751,982.86. The margin of safety (MOS) as percentage of

sales is 38.12%. The sale is allowed to drop about 38.12% before the company will

incurred a loss. All the data calculation is shown in the next section.

41

Page 42: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.7.2 Data Calculation

All the data based on 500,000 tons/year producing MTBE from existing plant.

Table 3.7 Values in USD converted to RM

(Sources: Data collected from table 3.6)

Total revenue, TR RM 659,053,000.00Total variable cost, TVC RM 504,754,000.00Total fixed cost, TFC RM 57,285,000.00

Total Revenue (TR), MTBE (500,000 ton),

TR = Quantity of MTBE X Price of MTBE

= QMTBE X PMTBE

= 500,000 tons X USD346.87 X 3.8

= RM 659,053,000

Total cost = total fixed cost + total variable cost

TC = TFC + TVC

Where,

Total fixed cost = 500,000 ton X USD30.13 X 3.8

= RM 57,285,000.00

Total variable cost = 500,000 ton X USD (226.4 + 39.26) X 3.8

= RM 504,754,000.00

∴ Total cost, TC = RM57,285,000.00 + RM 504,754,000.00

= RM 562,039,000.00

Tables 3.7 represent cost per unit ton converted into Ringgit Malaysia (RM), taking

data’s directly from the table 3.6.

Table 3.8 Values in USD converted to RM per ton

(Sources: Data collected from table 3.6)

Revenue (RM) per ton RM1,318.00Variable cost (RM) per ton RM 1,009.51Fixed cost (RM) per ton RM114.57

Break-even point in ton can be calculated based on formula equation, which given by

follow:

42

Page 43: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Break-even point, BEP (tons) = Total Fixed costContribution/ton

where,

Contribution/ton = revenue / ton - variable cost / ton

∴ BEP (tons) = ______RM 57,285,000.00_____(RM1, 318.00 - RM 1,009.51)

= 185,629.85 tons (the minimum capacity)

Next, Break-even point in RM can be calculated based on formula equation, which

given by follow:

∴ BEP (RM) = Break-even point, BEP (tons) X revenue / ton

= 185,629.85 tons X RM1, 318.00

= RM 244,679,817.14

Beside that, margin of safety and percentage of sale can be calculated as follows:

For 500,000 ton/year production,

∴ Margin of safety (MOS) in units = Budgeted sale (units) - BEP (units)

= 500,000 tons - 185,629.85 tons

= 314,370.15 tons

∴ Margin of safety (MOS) in RM = Budgeted sale (RM) - BEP (RM)

= RM 659,053,000.00 - RM 244,679,817.14

= RM 414,373,182.86

∴ Margin of safety (MOS) as percentage of sales = MOS (RM) x 100% Sales(RM)

= RM 414,373,182.86 x 100% RM 659,053,000

= 62.87%

43

Page 44: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

For 300,000 ton/year production,

∴ Margin of safety (MOS) in units = Budgeted sale (units) - BEP (units)

= 300,000 tons - 185,629.85 tons

= 114,370.15 tons

∴ Margin of safety (MOS) in RM = Budgeted sale (RM) - BEP (RM)

= RM 395,431,800 - RM 244,679,817.14

= RM 150,751,982.86

∴ Margin of safety (MOS) as percentage of sales = MOS (RM) x 100% Sales(RM)

= RM150,751,982.86 x 100% RM 395,431,800

= 38.12%

Table 3.9 shown that the calculation of break-even point by using excel.

Table 3.9: Data calculation by using excel in RM

(Sources: Data taking from table 3.7)

44

Page 45: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CAPACITY TFC1 TVC1 TR1 TC1

0 57,285,000.00 0 0 57,285,000.00

10000 57,285,000.00 10,095,080.00 13,181,060 67,380,080.00

20000 57,285,000.00 20,190,160.00 26,362,120 77,475,160.00

40000 57,285,000.00 40,380,320.00 52,724,240 97,665,320.00

60000 57,285,000.00 60,570,480.00 79,086,360 117,855,480.00

80000 57,285,000.00 80,760,640.00 105,448,480 138,045,640.00

100000 57,285,000.00 100,950,800.00 131,810,600 158,235,800.00

120000 57,285,000.00 121,140,960.00 158,172,720 178,425,960.00

140000 57,285,000.00 141,331,120.00 184,534,840 198,616,120.00

160000 57,285,000.00 161,521,280.00 210,896,960 218,806,280.00

180000 57,285,000.00 181,711,440.00 237,259,080 238,996,440.00

200000 57,285,000.00 201,901,600.00 263,621,200 259,186,600.00

220000 57,285,000.00 222,091,760.00 289,983,320 279,376,760.00

240000 57,285,000.00 242,281,920.00 316,345,440 299,566,920.00

260000 57,285,000.00 262,472,080.00 342,707,560 319,757,080.00

280000 57,285,000.00 282,662,240.00 369,069,680 339,947,240.00

300000 57,285,000.00 302,852,400.00 395,431,800 360,137,400.00

320000 57,285,000.00 323,042,560.00 421,793,920 380,327,560.00

340000 57,285,000.00 343,232,720.00 448,156,040 400,517,720.00

360000 57,285,000.00 363,422,880.00 474,518,160 420,707,880.00

380000 57,285,000.00 383,613,040.00 500,880,280 440,898,040.00

400000 57,285,000.00 403,803,200.00 527,242,400 461,088,200.00

420000 57,285,000.00 423,993,360.00 553,604,520 481,278,360.00

440000 57,285,000.00 444,183,520.00 579,966,640 501,468,520.00

460000 57,285,000.00 464,373,680.00 606,328,760 521,658,680.00

480000 57,285,000.00 484,563,840.00 632,690,880 541,848,840.00

500000 57,285,000.00 504,754,000.00 659,053,000 562,039,000.00

CHAPTER 4

45

Page 46: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

PLANT LOCATIONS AND SITE SELECTION

4.1 PLANT LOCATION

The location of the plant can have a crucial effect on the profitability of a project and the

scope for future expansion. Many factors must be considered when selecting a suitable

site. A good location is required to optimise the production of the plant. It is important to

know that, not all Malaysian industrial park caters the need of a chemical plant. Also not

all industrial park allows the building of chemical plants. Our industrial parks are divided

into categories such as: -

1. Light industrial

2. Medium industrial

3. Heavy industrial

4. General industrial

5. Hi-tech industrial

4.2 GENERAL CONSIDERATION ON THE SITE SELECTION

All the information about plant locations are based on the data gathered from the

Malaysian Industrial Development Authority (MIDA). And we refer detail information on

important factors that need to be considered in the site selection. In the process of

selecting the location, we did some evaluation. Among the principle factors considered

are:

4.2.1 Location With Respect To Marketing Area

For materil that are produced in bulk quantities, such as cement, fertilizer, raw material

of petrochemical product, where the cost of product per tone is relatively low and the

cost of transport a significant fraction of the sales price, the plant must located close to

the primary market. This consideration will be less important for low volume production,

high priced products; such as pharmaceuticals, plastisizer and etc. in an international

46

Page 47: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

market, there may be an advantage to be gained by locating the plant within an area

with preferential tariff agreement.

4.2.2 Raw Material Supply

The availability and price of suitable raw materials will often determine the site location.

Plant producing bulk chemicals are best located close to the source of the major raw

material, where this is also close to the marketing area.

4.2.3 Transport Facilities

The transport of materials and products to and from the plant will be an overriding

consideration in site selection. If practicable, a site that we are consider that close to at

least two major forms of transport: road, rail, waterway or a sea port. Road transport

being increasing used, and is suitable for local distribution from central warehouse. Rail

transport will be cheaper for the long distance transport of bulk chemicals

. Air transport is convenient and efficient for the movement of personnel and

essential equipment and supplies and the proximity of the site to a major airport also

considered.

4.2.4 Availability of Labour

Labour that will be needed for construction of the plant and its operation. Skilled

construction workers will usually be brought in from outside the site area, but there

should be an adequate pool of unskilled labour available locally and labour suitable for

training to operate the plant. Skill tradesman will be needed for plant maintenance.

Local trade union customs and restrictive practices will have to be considered when

assessing the availability and suitability of the local labour for requirement and training

.

4.2.5 Availability of Utilities

47

Page 48: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Chemical processes invariably require large quantities of water for cooling and general

process used and the plant must be located near a source of water of suitable quality.

Process water may be drawn from a river, wells or purchased from a local authority.

At some site, the cooling water required can be taken from a river or lake or

from the sea; at other locations cooling towers will be needed.

Electrical power will be needed at all sites. Electrochemical processes that

required large quantities of power: for example, aluminium smelters need to be located

close to a cheap source of power. A competitively priced fuel must be available onsite

for steam and power generation.

4.2.6 Environmental Impact and Effluent Disposal

All industrial processes produce waste products and full consideration must be given to

the difficulties and cost of their disposal. The disposal of toxic and harmful effluents will

be covered by local regulations and the appropriate authorities must be consulted

during the initial site survey to determine the standards that must be met.

An environmental impact assessment should be made for each new project or

major modification of addition to an existing process.

4.2.7 Local Community Considerations

The proposed plant must fit in with and be acceptable to the local community. Full

consideration must be given to the safe location of the plant so that it does not impose

a significant additional risk to the community.

On a new side, the local community must be able to provide adequate facilities

for the plant personnel: schools, banks, housing and recreational and cultural facilities.

4.2.8 Land (site consideration)

48

Page 49: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sufficient suitable land must be available for the proposed plant for future expansion.

The land should ideally be flat, well drained suitable load-bearing characteristics. A full

site evaluation should be made to determine the need for piling or other special

foundations.

4.2.9 Political and Strategic Considerations

Capital grants, tax concessions and other inducements are often given by government

to direct new investment to preferred locations such as areas of high unemployment.

The availability of such grants can be the overriding factor in site selection.

4.3 OVERVIEW ON PROSPECTIVE LOCATIONS

Our process is a petrochemical base process; therefore we choose to locate our plant in a

petrochemical complex. The reason is quite simple; a petrochemical complex could

simplify the formation and the maintenance of a chemical plant. It could also cut the daily

operation cost and saving us the hassle of transportation.

In Malaysia there are only three such places, known as the Integrated

Petrochemical Complexes. These complexes are situated in each of the site below:

1. Telok Kalong Industrial Park.

2. Tanjung Langsat Industrial Park.

3. Bintulu Industrial Park.

Other than the above factors, the capacity of plant was also taken into consideration in

determining the suitability of site. Plant capacity will determine how big the space required

to build the plant and the storage area and also the mode of transportation to be use.

The manufacture of MTBE is classified as a petrochemical project. Several

locations of industrial area particular at Teluk Kalong Industrial Area in Terengganu,

Tanjung Langsat Industrial Area in Johor and Bintulu Industrial Area, Sarawak that we are

refer for location.

49

Page 50: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.3.1 Teluk Kalong

Teluk Kalong Industrial Estate located 9.6 km from Kemaman. Total area available

167.46 hectares. The price of land in ranges RM 0.46 to RM 4.18 per Feet Square.

This area is proposed for petrochemical and heavy industry petrochemical.

The Electricity is generated at the following station. Total generation capacity is

900 MW. Local consumption is less than 1/3. No major breakdown, low frequency of

interruption. Water most plentiful with surplus capacity. Water supply capacity at

various treatment plants total 331000-meter cube per day, with planned upgrading for

additional requirement. Kenyir Lake with 39000 hectares of water with 134 metre

average depth, make Terengganu a potential export of water middle East. Water

supply is in Bukit Shah. Water tariffs (industrial) are RM1.15 metre cube. The raw

materials supplier of isobutene is availability from Chevron Philips Chemical Company

LP, United State and methanol is availability from Petronas Malaysia, Labuan.

1. Airport facilities

• Terengganu major industrial locations are serve by 3 airports

- Kuantan

- Kerteh

- Kuala Teregganu

• Kuala Teregganu

2. Port Facilities

• Kemaman Port, Kerteh Port and Kuantan Port

4.3.2 Tanjung Langsat Industrial Park

Tanjung Langsat is designed as hub for heavy/medium industries with all the

necessary infrastructure and service facilities. 91.43 km distance from Johor Baharu.

The infrastructure works such as the Pasir Gudang – Segamat Highway. Sungai

Johore Bridge and dedicated Port in Tanjung Langsat. Tanjung Langsat Industrial

Complex is a sprawling area just a stone’s through from Pasir Gudang Industrial Area.

A total hectare still available is 1,085.95. Selling price is RM8 to RM22 square feet. In

term of seaport two seaports are currently being constructed at Tanjung Pelepas,

50

Page 51: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

located 40 km west of Johore Baharu city and Tanjung Langsat located 10 km east of

the Johore Port. Tenaga Nasianal Berhad (TNB) provides electricity.

Two airports in the 50km radius. There is the Sultan Ismail International Airport

(common known locally as Senai Airport) in Johore Baharu and the Changi

International Airport in Singapore. The Sultan Ismail International Airport, which is

located about 30km to the north west of JB city, is currently being expended and

upgrades to become the regional airport for southern peninsular Malaysia.

4.3.3 Bintulu

The distance from nearest town is 224.29 km from Sibu. Type of industries is light and

medium petrochemical. Area available is 77 hectares. Selling price RM2.5 to RM10 per

feet square. Electricity supplies by Sarawak Electricity Supply Cooperation (SESCO).

• Airport facilities - Bintulu Airport

• Port Facilities - Bintulu Port

51

Page 52: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.1 The Comparison of The Potential Site Location:

Teluk Kalong Industrial Park

Tanjung Langsat Industrial Park

Bintulu Industrial Park

Distance from the nearest town

9.6 km from Kemaman91.43 km from Johor

Baharu224.29 km from Sibu

Raw MaterialIsobutane from US and methanol from Labuan

Isobutane from US and methanol from Labuan

Isobutane from US and methanol from Labuan

Types of Industry

Petrochemical and heavy industry

Petrochemical light and medium

Petrochemical light and medium

Area Available 167.46 hectares 1085.98 hectares 77 hectares

Land Price

(RM/ft 2)RM 0.46 - 4.18 RM 8.00 - 22.00 RM 2.50 - 10.00

Electricity Supply

Tenaga National Berhad Tenaga National BerhadSarawak Electrycity Supply Cooperation

(SESCO)

Water SupplyBukit Shah Water

TreatmentSyarikat Air Johor andLogi Air Sg. Layang

Syarikat Air Sarawak

Road Facilities

Kuala Terengganu-Kuantan-Kuala Lumpur-

Kuala Terengganu-Kerteh-Teluk Kalong-Kuantan-

Kuala Lumpur

North-South Highway from Bukit Kayu Hitam to

Singapore-

Major Road : Bintulu - Sibu and Bintulu - Miri

Airport FacilitiesKuala Terengganu Airport Kerteh Airport

Senai International Airport

Bintulu Airport

Port FacilitiesKemaman Port, Kerteh Port Kuantan Port

Pasir Gudang Port Bintulu Port

Water Tariffs

(RM/m3)RM 1.15

RM 1.68 (0-20 m 3) RM2.24 (more than

20 m3)

RM 0.95 (0 -25 m 3) RM1.20 (more than

25 m 3) (Source: MIDA)

A few proposed plant sites were narrowed down based on the above factors (table 4.2).

Table 4.2 is a summary of location and factors being considered. After detailed study of

52

Page 53: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

the factors, each was given weightage and was estimated. The result tabulated in table

4.2 for the purpose of comparison.

Table 4.2 The Comparison of Location in term of Weightage Study

WeightageTelok Kalong

Industrial Area

Tanjung Langsat

Industrial Area

Bintulu Industrial Area

Marketing Area 10 8 7 7

Raw Material 10 8 9 9

Transport 10 8 7 6

Availabillity of Labour

10 8 8 7

Utilities 10 8 9 7

Total Land Available

10 8 9 8

Climate 10 9 9 9

Price of Land 10 9 5 7

Local Community

Consideration 10 6 8 9

Incentives 10 8 8 8

TOTAL 100 80 79 77

∴ 0 to 10 with 10 is the best

Table 4.3 The Electricity Tariffs (Industrial Tariff) for Peninsular Malaysia and Sarawak

53

Page 54: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Tariff Cost per kWh Peninsular Malaysia

Tariff D (Low Voltage, and less than 6.6 kV supply) for all consumptions

25.8

Tariff E1 (Medium Voltage General, 6.6 kV - 66 kV supply) for all consumptions. For each kW of maximum demand per month: RM 17.30

19.8.

Tariff E2 (Medium Voltage Peak/Off-Peak, 6.6 kV - 66kV supply)

Peak period (0800-2200 hours), 20.8

Off-Peak period (2200-0800 hours). 12.8

For each kW of maximum demand per month during peak period: RM21.70

Tariff E3 (High Voltage Peak/Off-Peak, more than 132 kV supply)

Peak period (0800 -2200 hours), 17.8Off-Peak period (2200 - 0800) hours). 10.8

For each kW of maximum demand per month during peak period: RM 20.80

Sarawak Tariff 11

1st 100kWh 40In excess of 100kWh to 3000 kWh 30In excess of 3000 kWh 21Minimum charge per month: RM 10.00Tariff 12 All units 17

For each kW of maximum demand per month: RM12.00

Minimum charge : RM 12.00 per kW x billing demandTariff 13 (Peak/Off-Peak)Peak period ( 0700 - 2400 hours) 17Off-Peak period ( 0000 - 0700 hours) 10For each kW of maximum demand per month during peak period: RM20.00Minimum charge: RM 20.00 per kW x billing demand.

(Source: MIDA)

54

Page 55: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.4 CONCLUSION

Based on the factor weightage studied, it can be concluded that Telok Kalong Industrial

Estate is the most suitable and practical location to choose as a site for MTBE plant.

The philosophy of in situ consumption of much of the production MTBE,

together with remaining product aimed directly at the export market and also makes the

need for port facilities of paramount importance. The Tanjung Langsat and Bintulu

Industrial Area are not impressive for MTBE plant. There are many other reasons

influences our decision including:

• Nearest of the Kuantan Port, Kemaman Port and Kerteh Port facilities is more

convenient and economically for export and import purposes.

• Excellent and consistent support from bulky oil, gas and chemical supplier from

Kerteh.

Constantly upgrading existing and developing new infrastructure, facilities and supporting

industries. These include the construction of roads; to increase accessibility to and from

the estates are scheduled.

55

Page 56: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 5

ENVIRONMENTAL CONSIDERATION

5.1 INTRODUCTION

Nowadays, environmental issues become very important. Besides this, a good waste

treatment system is also important in order to reduce and minimize

environmental pollutants. The chemical waste in the form of solid, liquid and

gases must be treated before being discharged into sewage, drain and

atmospheres.

Any chemical plant to be set up in Malaysia must follow the rules and

regulations under the Department of Environment (DOE) Malaysia, which includes the

Environmental Quality Act 1974. Under Environmental Quality Act (Sewage and

Industrial Effluents) Regulation 1979 and Environment Quality Act (Clean Air) 1978.

The plant owner or waste generator must ensure that waste generated disposed

appropriately to prevent environmental pollution. The proper and suitable methods

should be implemented in dealing with the waste disposal. Kualiti Alam Sdn. Bhd is

one of the licensed contractors specialized in the industrial waste disposal in Malaysia.

MTBE plant is not excluded from these regulations. As our plant produces

MTBE and other byproducts like raffinate but generally they are not hazardous to the

environment and human if safety measures are taken into consideration. These

environmental considerations depend on the location of our plant. The plant will follow

the Standard B of water quality measurement and also need some waste treatment

facilities to minimize the pollution from our plant.

56

Page 57: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

STACK GASES

Gas Emission Treatment

Direct flame combustion was used to burn the excess gas. Flare is usually open ended

combustion unit. Therefore, the combustion process will be controlled by flow

rate of gases mixture to prevent incomplete combustion.

Another treatment is thermal combustion. It is an incinerator used in the cases

where the concentration of combustible gases is too low to make direct flame

incineration insufficient condition. The temperature of operation depends upon the type

of pollutant in waste gas. Thermal combustion must be carefully designed to provide

safe, efficient operation and to prevent incomplete combustion. Time, temperature, and

oxygen must be carefully monitored. (Howard et. al 1985)

Stack gas means the product of combustion process usually occur at machine or

generator. It is usually the fuels used occurred in the complete combustion

process, but it produced unwanted gas such as carbon monoxide, sulphur oxide

and other gases.

In our MTBE plant, the stack gases is only Hydrogen and it is stored in a

special tank before being sold to interested company at market price.

5.3 WASTEWATER TREATMENT

5.3.1 Wastewater Characteristics

Wastewater characteristics vary widely from industry to industry. Obviously, the

specific characteristics will affect the treatment techniques chosen for use in meeting

discharge requirements. Because of the large number of pollutant substances,

wastewater characteristics are not usually considered on a substance-by-substance

basis. Rather, substances of similar pollution effects are grouped together into classes

of pollutants or characteristics are indicated below.

5.3.1(a) Priority Pollutants

57

Page 58: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Recently, greatest concern has been for this class of substances for the reasons given

previously. These materials are treated on an individual-substance basis for regulatory

control. Thus each industry could receive a discharge permit that lists an acceptable

level for each priority pollutant.

5.3.1(b) Organics

The organic composition of industrial wastes varies widely, primarily due to the

different raw materials used by each specific industry. These organics include proteins,

carbohydrates, fats and oils, petrochemicals, solvents, pharmaceutical, small and large

molecules, solids, and liquids. Another compilation is that a typical industry produces

many diverse waste streams. Good practice is to conduct a material balance

throughout an entire production facility. This survey should include a flow diagram,

location and sizes of piping, tanks, and flow volumes, as well as an analysis of each

stream.

An important measure of the waste organic strength is the 5-day biochemical

oxygen demand (BOD5). As this test measures the demand for oxygen in the water

environment caused by organics released by industry and municipalities, it has been

the primary parameter in determining the strength and effects of a pollutant. This test

determines the oxygen demand of a waste exposed to biological organisms (controlled

seed) for an incubation period of five days. Usually this demand is caused by

degradation of organics according to the following simplified equation, but reduced

inorganics in some industries may also cause demand (i.e., Fe2+, S2- and SO32-).

Organic waste + O2 CO2 +H2O

In general, low-molecular-weight water-soluble organics are biodegraded

readily. As organic complexity increases, solubility and biodegrability decrease. Soluble

organics are metabolized more easily than insoluble organics. Complex carbohydrates,

proteins and fats and oils must be hydrolyzed to simple sugars, aminos, and other

organics acids prior to metabolism. Petrochemicals, pulp and paper, slaughterhouse,

58

Page 59: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

brewery, and numerous other industrial wastes containing complex organics have been

satisfactorily treated biologically, but proper testing and evaluation is necessary.

5.3.1(c) Inorganics

The inorganics is most industrial wastes are the direct result or inorganic compounds in

the carriage water. Soft-water sources will have lower inorganics than hard-water or

saltwater sources. However, some industrial wastewaters can contain significant

quantities of inorganics which result from chemical additions during plant operation.

Many food processing wastewaters are high in sodium.

While domestic wastewaters have a balance in organics and inorganics, many

process wastewaters from industry are deficient in specific inorganic compounds.

Biodegration of organic compounds requires adequate nitrogen, phosphorus, iron, and

trace salts. Ammonium salts or nitrate salts can provide the nitrogen, while phosphates

supply the phosphorus.

5.3.1(d) pH and Alkalinity

Wastewaters should have pH values between 6 and 9 for minimum impact on the

environment. Wastewaters with pH values less than 6 will tend to be corrosive as a

result of the excess hydrogen ions. On the other hand, raising the pH above 9 will

cause some of the metal ions to precipitate as carbonates or as hydroxides at higher

pH levels. Alkalinity is important in keeping Ph values at the right levels. Bicarbonate

alkalinity is the primary buffer in wastewaters. It is important to have adequate alkalinity

to neutralize the acid waste components as well as those formed by partial metabolism

or organics.

Many neutral organics such as carbohydrates, aldehydes, ketones, and

alcohols are biodegraded through organics acids which must be neutralized by the

available alkalinity. If alkalinity is inadequate, sodium carbonate is a better form to add

than lime. Lime tends to be hard to control accurately and results in high pH levels and

precipitation of the calcium which forms part of the alkalinity. In a few instances,

sodium bicarbonate may be the best source of alkalinity.

59

Page 60: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.3.1(e) Temperature

Most industrial wastes tend to be on the warm side. For the most part, temperature is

not a critical issue below 37oC if wastewaters are to receive biological treatment. It is

possible to operate thermophilic biological wastewater-treatment systems up to 65oC

with acclimated microbes. Low-temperature operations in northern climates can result

in very low winter temperatures and slow reaction rates for both biological treatment

systems and chemical treatment systems.

Increased viscosity of wastewaters at low temperatures makes solid separation

more difficult. Increased viscosity of wastewaters at low temperatures makes solid

separation more difficult. Efforts are generally made to keep operating temperatures

between 10 and 30oC if possible.

5.3.2 Liquid Waste Treatment

5.3.2(a) Equalization Treatment

Liquid treatment generally is necessary in any plant. In our plant, we also have liquid

treatment but in general, we only state the general method, as our plant does not

produce any significant liquid waste. In any liquid waste treatment, we need

equalization treatment. The equalization treatment is an initial procedure in liquid waste

treatment. The purpose of equalization is to minimize and control the fluctuation in

liquid waste characteristic. Besides it provides the suitable and optimum condition for

biological and chemical treatment. It also provides adequate damping to minimize the

chemical consumption. The procedure will occur in the equalization tank. The size of

tank and time of equalization process depend on the liquid waste amount.

The Activated Sludge process will be used for this treatment. It is carried out in

Aerobic condition. The main purpose of activated sludge process is to remove soluble

and insoluble organic matter that converted into flocculants microbial suspension and

settable microbial. It also permits the use of gravitational solid liquid separation

technique for the above requirement.

The organic matter where measured in the form of BOD and COD serves as

food and energy source for microbial growth. It converts the pollutant into microbial cell

60

Page 61: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

and oxidized end product such as CO2 and H2O by microbial activities. Therefore,

Submersible Aerator as mixing device will supply the oxygen and nutrient into aeration

tank and therefore improves the quality of the liquid. (Howard et. al, 1985)

5.3.2(b) Solid Waste Treatment

The solid waste treatment will be minimized by regenerating the catalyst. Regeneration

processes depend on the characteristic of catalyst after whole reaction. Licensed

contractor will dispose the solid waste to follow the DOE regulation. By the way,

the scheduled maintenance activities will be implemented.

Dewatering system will be used to solidify and extract the catalyst. Therefore,

clarifier and filter press were used in these treatments. Clarifier is used to clarify any

impurities before going through the filters. The size of equipment depends on the flow

rate and holding time of these processes. Maintenance activities will be scheduled

based on the availability of workers and machines. Skilled and experienced workers

will do the maintenance activities, (Bailed, 1995).

61

Page 62: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 5.1 Functional Elements in a Solid-waste Treatment System.

IndustrialProcess

Waste Reduction

Waste Generation

Re-use

Storage

Collection

Processing/Recovery

Transfer/Transport

DisposalRecycling/

Reuse

62

Page 63: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.3.3 Waste Minimization

Waste minimization means the optimization process to minimize the waste come out of

the plant. It will be done by source reduction and recovery of the sources. The source

reduction refers to preventative measured taken to reduce the amount of waste, which

produced in this process. Recovery of the sources is aimed to reuse the excess

methanol to produce the MTBE.

Waste production from the plant could be reduced by implementing these

procedures:

- Raw material modification,

- Product reformulation,

- Process modification,

- Improvement in operating practices.

The most important is by improving the product yield and this means

minimization of waste generation. It will be accomplished through improvement in

catalyst efficiency and proper maintenance activities.

63

Page 64: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 6

SAFETY CONSIDERATION

6.1 INTRODUCTION

For years, those employed in the chemical industry have known that the safe operation of

chemical plant is essential to the industry’s continued ability to survive. The human,

political and financial costs of having accidents are just too high for the chemical

industry to not exhibit excellence in their efforts to operate plants in safe and

environmentally responsible ways. The chemical industry has an outstanding record in

both transportation safety and the safe operations of its processes. That effort has

resulted in a dramatic and steady decline in releases and waste produced at chemical

sites.

Actions that should be taken to avoid serious chemical plant accidents are as follows:

1. In most cases involving large volumes of highly hazardous chemicals, excess

flow valves are in place that would stop a rapid flow of the chemicals

2. When highly hazardous chemicals are involved, processes have fixed

protection, as well as trained emergency response teams that could handle the

incident.

3. Appropriate reaction control or inhibiting systems are in place to interrupt

runaway reactions if cooling, heating and pressure relief are not considered

adequate.

4. Control systems are designed to detect heat or pressure of a chemical reaction

and to control that reaction.

5. Work more closely with local and state law enforcement groups.

64

Page 65: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

6.2 MATERIAL SAFETY DATA SHEET

6.2.1 Isobutane (Instrument Grade)

Product Number(S): 0001020533, 0001020534, 0001020535, 0001020536

Synonyms: Methylpropane; Iso

Company Identification:

Chevron Phillips Chemical Company Lp

10001 Six Pines Drive

The Woodlands, Tx 77380

6.2.1.1 Product Information:

Msds Requests: (800) 852-5530

Technical Information: (800) 852-5531

Colorless liquefied gas, odorless.

- Flammable gas. May cause flash fire

- Contents under pressure

- Detection of leak via sense of smell may not be possible if odorant has degraded

- Contact with liquefied gas can cause frostbite

- Liquid can cause eye and skin injury

- Reduces oxygen available for breathing

6.2.1.2 Physical And Chemical Properties

Appearance and odor: colorless liquefied gas, odorless.

Ph: na

Vapor pressure: 72 psia @ 37.8 ºc

Vapor density (air=1): 2.1

Boiling point: -12°c (10.4°f)

Solubility: negligible

Percent volatile: 100 % volume

Specific gravity: 0.564 @ 15.6 ºc

Evaporation rate: >1

65

Page 66: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

6.2.1.3 Immediate Health Effects:

Eye: Because the liquid product evaporates quickly, it can have a severe chilling effect

on eyes and can cause local freezing of tissues (frostbite). Symptoms may include

pain, tearing, reddening, swelling and impaired vision.

Skin: Because the liquid product evaporates quickly, it can have a severe chilling

effect on skin and can cause local freezing of tissues (frostbite). Symptoms may

include pain, itching, discoloration, swelling, and blistering. Not expected to be harmful

to internal organs if absorbed through the skin.

Ingestion: Material is a gas and cannot usually be swallowed.

Inhalation: This material can act as a simple asphyxiant by displacement of air.

Symptoms of asphyxiation may include rapid breathing, in coordination, rapid fatigue,

excessive salivation, disorientation, headache, nausea, and vomiting.

Convulsions, loss of consciousness, coma, and/or death may occur if exposure to high

concentrations continues.

6.2.1.4 First Aid Measures

Eye: Flush eyes with water immediately while holding the eyelids open. Remove

contact lenses, if worn, after initial flushing, and continue flushing for at least 15

minutes. Get immediate medical attention.

Skin: Skin contact with the liquid may result in frostbite and burns. Soak contact area

in tepid water to alleviate the immediate effects and get medical attention.

Ingestion: No specific first aid measures are required because this material is a gas

and cannot usually be swallowed.

Inhalation: For emergencies, wear a niosh approved air-supplying respirator. Move

the exposed person to fresh air. If not breathing, give artificial respiration. If breathing is

difficult, give oxygen. Get immediate medical attention.

6.2.2 N-Butane

N-Butane synonym with I-Butane, Butane, and Normal Butane is a flammable gas. N-

Butane is heavier than air and may travel considerable distance to an ignition source.

66

Page 67: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

N-Butane is listed under the accident prevention provisions of section 112(r) of the

Clean Air Act (CAA) with threshold quantity (TQ) of 10000 pounds.

Physical and Chemical Properties

Parameter value units

Physical state : Gas

Vapor pressure at 70oF : 31 psia

Vapor density at STP : 2.07

Evaporation point : not available

Boiling point : 31.1 oF

Freezing point : -0.5 oC

pH : not available

Solubility : insoluble

Odor and appearance : a colourless and odourless gas

Stability : stable

Condition to avoid : high temperature

6.2.2.1 Handling and storage

Protect cylinders from physical damage. Store in cool, dry, well- ventilated area away

from heavily trafficked areas and emergency exits. Do not allow the temperature where

cylinders are stored to exceed 130oF. Cylinders should be stored upright and firmly

secured to prevent falling or being knocked over. Full and empty cylinders should be

segregated. Use a “first in first out” inventory systems to prevent full cylinders from

being stored for excessive periods of time. Never carry a compressed gas cylinder or a

container of a gas in cryogenic liquid form in an enclosed space such as a car trunk,

van or station wagon. A leak cans re4sult in a fire, explosion, asphyxiation or a toxic

exposure.

6.2.3 Methanol

Methanol synonyms with Methyl alcohol and in chemical family alcohol with the

formula CH3OH. Methanol is a clear, colourless, mobile, volatile, flammable liquid and

it’s soluble in water, alcohol and ether.

67

Page 68: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Physical and Chemical properties:

Parameter value

Physical state : liquid

Boiling Point : 64.7oc

Vapor Pressure (20oc) : 128 mb

Vapor Density (air=1) : 1.11

Solubility in water ,%wt : full

Specific Gravity : 0.792 g/cm3

Appearance and odor : liquid-colorless-odor specific

Fire and Explosion Hazard data:

Flash point : closed cup: 12oc

Flammable limits, % vol : Lel: 6, Uel : 36.5

Extinguishing media : Foam – CO2 –halogenated agents

Special fire fighting : Avoid contact with oxidizing materials

Unusual fire and explosion : Moderate

Reactivity Data:

Stability : Medium

Conditions to avoid : Oxidizing materials

Incompatibility : Sulfo-chromic mixtures

Special Precautions

Precaution to be taken in handling and storing Methanol: store in iron or steel

containers or tanks. Small quantities can be stored in reinforced glass containers.

6.2.4 MTBE

6.2.4.1 Physical state, appearance

MTBE is chemically stable; it does not polymerize, nor will decompose under normal

conditions of temperature and pressure. Unlike most ether, MTBE does not tend to

form peroxides (auto-oxidize). The physical state of MTBE is that MTBE is in the form

of liquid at room temperature (25oC). It is a colourless liquid with the billing point at

68

Page 69: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

55.2oC 131.4oF. The freezing point of MTBE is –108.6oC –163.5oC. The density of

MTBE at 25oC is 735g/cm3.

6.2.4.2 Physical dangers

MTBE is non-reactive. It does not react with air, water, or common materials of

construction. The reactivity of MTBE with oxidizing materials is probably low. However,

without definitive information, it should be assumed that MTBE reacts with strong

oxidizers, including peroxides.

6.2.4.3 Chemical dangers

MTBE is highly flammable and combustible when exposed to heat or flame or spark,

and it is a moderate fire risk. Vapours may form explosive mixtures with air. It is

unstable in acid solutions. Fire may produce irritating, corrosive or toxic gases. Runoff

from fire control may contain MTBE and its combustion products.

Occupational exposure limits (OELs)

Routes of Exposure

6.2.4.4 Inhalation risk

Like other ethers, inhalation of high levels of MTBE by animals or humans results in the

depression of the central nervous system. Symptoms observe red in rats exposed to

4000 or 8000 ppm in air included labored respiration, ataxia, decreased muscle tone,

abnormal gait, impaired treadmill performance, and decreased grip strength. These

symptoms were no longer evident 6 hours after exposure ceased. A lower level of

MTBE, 800ppm did not produce apparent effects (Daughtrey et al., 1997).

A number of investigations have been conducted to examine the self-reported

acute MTBE in gasoline vapors during use by consumers. This research includes both

epidemiological studies and studies involving controlled exposure of volunteers to

MTBE at concentrations similar to those encountered in refueling an automobile

(Reviewed in USEPA, 1997, and California EPA, 1998). In general, the studies

involving controlled human exposures in chambers to levels of MTBE similar to those

experienced during refueling and driving an automobile have not shown effects of

69

Page 70: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

MTBE on physical symptoms (e.g. irritation), mood, or performance based tests of

neurobehavioral function.

6.2.5 TBA (TERT - BUTYL ACOHOL)

CAS Number: 75-65-0

Synonyms: tert-Butanol

2-methyl-2-propanol

TBA

t-butylhydroxide

1,1-dimethylethanol

trimethylmethanol

trimethylcarbinol

6.2.5.1 Recognition

NIOSH/OSHA Health Guideline. Summarizes pertinent information about for workers

and employers as well as for physicians, industrial hygienists,and other occupational

safety and health professionals who may need such information to conduct effective

occupational safety and health programs.

6.2.5.2 Evaluation

1. Health Hazards . Routes of exposure, summary of toxicology, signs and

symptoms, emergency procedure.

2. Workplace Monitoring and Measurement .

3. Medical Surveillance . Workers who may be exposed to chemical hazards

should be monitored in a systematic program of medical surveillance that is

intended to prevent occupational injury and disease. The program should

include education of employers and workers about work-related hazards,

placement of workers in jobs that do not jeopardize their safety or health, early

detection of adverse health effects, and referral of workers for diagnosis and

treatment.

70

Page 71: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

6.2.5.3 Controls

1. Exposure Sources and Control Methods .

2. Personal Hygiene Procedures .

3. Respiratory Protection . Conditions for respirator use, respiratory protection

program.

4. Personal Protective Equipment . Protective clothing should be worn to prevent

any possibility of skin contact. Chemical protective clothing should be selected

on the basis of available performance data, manufacturers' recommendations,

and evaluation of the clothing under actual conditions of use.

5. Emergency Medical Procedures . Material Safety Data Sheets (MSDS's) include

chemical specific information on emergency medical and first aid procedures as

referenced under the OSHA Hazard Communication standard, 29 CFR

1910.1200, (g)(2)(X). This standard requires chemical manufacturers and

importers to obtain or develop an MSDS for each hazardous chemical they

produce or import. Employers shall have an MSDS in the workplace for each

hazardous chemical, which they use.

6. Storage .

7. Spills and Leaks . In the event of a spill or leak, persons not wearing protective

equipment and clothing should be restricted from contaminated areas until

cleanup has been completed.

6.3 HAZARD IDENTIFICATION & EMERGENCY SAFETY & HEALTH RISK

ASSESSMENT

Safety & Health Risks vary with the type of industry & the magnitude of the emergency.

The severity of the risk too will vary with especially where there are chemicals,

combustible gases, potential for fire & explosion etc. These hazards may not only pose

a danger to the health of working in a particular plant but also the adjacent community.

In the event of a major disaster property both within and outside the plant will be

damaged. The real and potential hazards at the work place must be identified and the

Safety & Health Risks that they pose assessed. This will require a close scrutiny of all

71

Page 72: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

work place buildings, their design, electrical wiring, transport and storage facilities, the

work processes, workstation design, safe operating procedures, list of chemicals

substances used, their quantity, storage, daily transfer, safe usage and disposal.

MSDS’s of the chemical too have to be studied as regards their toxicity, volatility, and

their potential for a fire and/or explosion and adverse health affects both short term and

long term.

The possible emergencies/disaster in a industry could be:

• Fire/ explosion

• Chemical spill

• Radioactive material spill

• Biological material spill

• Personal injury

The best action plan is prevention from an emergency. This is where one has to

work closely with operation personnel to make sure that all operations are safe and

comply with OSH Legislations. All persons at work are aware of the safe procedure

and also follow those procedures. Unfortunately in the real world, mostly human

factors- accident & emergency do occur. This is why emergency response plans have

to be written up, communicated to all concerned and tested for effectiveness.

Depending on the gravity the workplace emergency can be categorized in to Level 1,

Level 2, or Lever 3 emergency.

Level 1 Emergency- the first responder without having to call the disaster

response team or outside help can effectively manage such incident. Examples; a

small fire easily smothered, chemical spill easily contained and cleaned, injury minor

and treated at site by rendering first aid.

Level 2 Emergency - an incident that requires technical assistance from the

disaster response team and may need outside help. Examples; fire that need technical

from trained personnel and specialized equipment spill that can only be properly

contained by specialized equipment.

72

Page 73: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Level 3 Emergency- these are major disaster that are difficult to contain even

with trained personnel and outside help. Examples, spill that cannot be properly

contained or abated even by highly trained team and the use of sophisticated special

equipment. Fire involving toxic material that is too large to control and are to burn. This

may require the evacuation of civilians across jurisdictional boundaries

73

Page 74: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

100 kgmole/hr

0.996 iC4H10

0.004 nC4H10

Stream S5 = 164.74 kgmole/hr

0.393 C4H8

0.393 H2

0.212 iC4H10

0.002 nC4H10

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 7

MASS BALANCE

7.1 SNAMPROGETTI UNIT (REACTOR AND REGENERATOR)

Assume steady-state system,

Basis = 100 kgmole/hr of S2

74

S2

Given from MSDS

Page 75: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The fraction at stream S2 acquired from isobutane instrument grade, MSDS.

Reaction occurred in the reactor,

iC4H10 C4H8 + H2

Flowrate in kgmole/hr of iC4H10 in the feed stream of S2 = 0.996 (100)

= 99.6 kgmole/hr iC4H10

Balanced Based upon the stoichoimetric ratio with 65% conversion of iC4H10 to obtain

C4H8.

Since, 65% conversion in the reactor,

∴ kgmole/hr of C4H8 obtained = 0.65 (99.6)

= 64.74 kgmole/hr

∴ 35% of iC4H10 unreacted = 99.6 - 64.74

= 34.86 kgmole/hr

Based upon stoichiometric ratio

(inert) (unreacted) (inert)

n C4H10 + iC4H10 C4H8 + H2 + iC4H10 + n C4H10

0.4 99.6 64.74 64.74 34.86 0.4

(kgmole/hr) (kgmole/hr)

Input OutputStream S2 S5

Component MW

kg/kgmole

Molar flow

kgmole/hr

Mass flow kg/hr Molar flow

kgmole/hr

Mass flow kg/hr

C4H8

H2

iC4H10

n C4H10

56

2

58

58

-

-

99.6

0.4

-

-

5776.8

23.2

64.74

64.74

34.86

0.4

3625.44

129.4

2021.88

23.4Total 5800 5800

75

Page 76: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

Stream S10 = 64.74 kgmole/hr

1 H2

Stream S11 = 100 kgmole/hr

0.6474 C4H8

0.3486 iC4H10

0.0040 nC4H10

Stream S9 = 164.74 kgmole/hr

0.393 C4H8

0.393 H2

0.212 iC4H10

0.002 nC4H10

S14 = 71.62 kgmole/hr

0.996 CH3OH0.004 H2O

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

7.2 SEPARATOR

Input OutputStream S9 S10 S11

Component MW

kg/kgmole

Molar flow

kgmole/hr

Mass flow

kg/hr

Molar flow

kgmole/hr

Mass flow

kg/hr

Molar flow

kgmole/hr

Mass flow

kg/hr

C4H8

H2

iC4H10

n C4H10

56

2

58

58

-

-

99.6

0.4

-

-

5776.8

23.2

-

64.74

-

-

-

129.4

-

-

64.74

64.74

34.86

0.4

3625.44

129.4

2021.88

23.4Total 5800 129.4 5670.6

7.3 MIXER

76

S13 = 64.74kgmole/hr

1 CH3OH

S27 = 0.406 kgmole/hr

0.3596 CH3OH0.6404 H2O

Page 77: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S15 kgmole/hr

C4H8

iC4H10

nC4H10

CH3OH

C5H12O

C4H10O

C2H6O

H2O

S14 = 71. 214 kgmole/hr

CH3OH

H2O

Stream S11 = 100 kgmole/hr

0.6474 C4H8

0.3486 iC4H10

0.0040 nC4H10

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Input OutputStream S13 S27 S14

Component MW

kg/kgmole

Molar flow

kgmole/hr

Mass flow

kg/hr

Molar flow

kgmole/hr

Mass flow

kg/hr

Molar flow

kgmole/hr

Mass flow

kg/hr

CH3OH

H2O

32

18

71.214

-

2278.848

-

0.146

0.26

4.67

4.68

71.36

0.26

2283.52

4.685Total 2278.848 9.356 2288.205

7.4 MTBE REACTOR

Assumption : 98% conversion of C4H8 (2% remains unconverted)

Reactions involve in the reactor,

1. C4H8 + CH3OH C5H12O

2. 2CH3OH C2H6O + H2O

3. C4H8 + H2O C4H10O

7.4.1 1st REACTION IN REACTOR

C4H8 + CH3OH C5H12O

77

Reactor

Page 78: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

98%

conv.

kgmole/hr

C4H8

CH3OH

C5H12O64.74 kgmole/hr

1 CH3OH

64.74 kgmole/hr

1 C4H8

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

kgmole/hr of C4H8 in the stream S11 = 100(0.6474)

= 64.74 kgmole/hr C4H8

Balance based upon stoichiometric ratio with 98% conversion.

CH3OH is classified an excess.

The unreacted of CH3OH (excess) = (71.36 - 64.74)

= 6.62 kgmole/hr

Since 98% conversion in the reactor,

kgmole/hr of C5H12O obtained = 0.98 (64.74)

= 63.44 kgmole/hr C5H12O obtained

From the stoichiometric ratio,

C4H8 + CH3OH C5H12O + C4H8 + CH3OH

64.74 71.214 63.44 1.3 7.92

unconverted

kgmole/hr kgmole/hr

Input OutputComponent MW Molar flow Mass flow Molar flow Mass flow

78

Reactor

Page 79: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

98%

conv.

kgmole/hr

CH3OH

C2H6O

H2O

7.92 kgmole/hr

1 CH3OH

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(kg/kgmole) (kgmole/hr) (kg/hr) (kgmole/hr) (kg/hr)C4H8

CH3OH

C5H12O

56

32

88

64.74

71.36

-

3625.44

2283.52

-

1.3

7.92

63.44

72.8

253.44

5582.72Total 5908.96 5908.96

7.4.2 2nd REACTION IN REACTOR

From 2nd reaction, stoichiometric ratio shown below:

Since the ratio between methanol and dimethylether is 2CH3OH : 1C2H6O ,

98% conversion methanol (CH3OH) into dimethylether (C2H6O) = 1.3 (0.98) 2

= 0.637 kgmole/hr

2CH3OH C2H6O + H2O + 2CH3OH

7.92 3.88 3.88 0.16

unconverted

kgmole/hr kgmole/hr

Input Output

79

Reactor

Page 80: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

1.3 kgmole/hr

1 C4H8

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Component MW

kg/kgmole

Molar flow

kgmole/hr

Mass flow

(kg/hr)

Molar flow

(kgmole/hr)

Mol

Fraction

Mass flow

(kg/hr)

CH3OH

C2H6O

H2O

32

46

18

7.92

-

-

253.44

-

-

0.16

3.88

3.88

0.02

0.49

0.49

5.12

178.48

69.84

Total 253.44 1.0 253.44

7.4.3 3rd REACTION IN REACTOR

The 3rd reaction and its stoichiometric below,

From 1st reaction, kgmole/hr of C4H8 remain is 1.3 and 3.88 kgmole/hr of H2O is

obtained in 2nd reaction.

Since C4H8 is limiting reactant to react with H2O, only 1.3 kgmole/hr of H2O needed to

react with C4H8

H2O is classified an excess.

The unreacted of H2O (excess) = (4.14 - 1.3)

= 2.84 kgmole/hr

C4H8 + H2O C4H10O + C4H8 + H2O

1.3 4.14 1.274 0.026 2.866

unconverted

kgmole/hr kgmole/hr

80

Page 81: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S11 = 100 kgmole/hr

0.6474 C4H8

0.3486 iC4H10

0.0040 nC4H10

4.166 kgmole/hr

0.3058C4H8

0.3058C4H10O

0.688H2O4.14 kgmole/hr

1 H2O

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Input Output

Component MW

kg/kgmole

Molar flow

kgmole/hr

Mass

flow

(kg/hr)

Molar

flow

kgmole/hr

Mass

flow

(kg/hr)

Molar

flow

kgmole/hr

Mass

flow

(kg/hr)C4H8

H2O

C4H10O

56

18

74

1.3

-

72.8

-

-

4.14

-

74.52

0.026

2.866

1.274

1.456

51.588

94.276

Total 1.3 72.8 4.14 74.52 4.166 147.32

7.4.4 OVERALL MASS BALANCE ON MTBE REACTOR

81

Reactor

Page 82: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S15 = 100.676 kgmole/hr

0.0002 C4H8

0.3261 iC4H10

0.0037 nC4H10

0.0015CH3OH

0.5934 C5H12O

0.0119 C4H10O

0.0363 C2H6O

0.0268 H2O

S14 = 71.36 kgmole/hr

1 CH3OH

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Input Input Output

S11 S14 S15

Component MW

(kg/kg

mole)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole

/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/h

r)

Mass

flow

(kg/hr)C4H8

iC4H10

n C4H10

CH3OH

C5H12O

C2H6O

C4H10O

H2O

56

58

58

32

88

46

74

18

64.74

34.86

0.4

-

-

-

-

-

3625.44

2021.88

23.2

-

-

-

-

71.36

-

-

-

0.26

-

-

-

2283.52

4.68

0.026

34.860

0.4

0.16

63.44

3.88

1.274

2.866

1.456

2021.88

23.2

5.12

5582.72

178.48

94.276

51.588

Total 100 5670.52 71.62 2288.2 106.906 7958.72

7.5 DISTILLATION COLUMN

Assume that 90% of methanol in bottom.

82

Reactor

Page 83: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S15 = 100.906 kgmole/hr

0.0002 C4H8

0.3261 iC4H10

0.0037 nC4H10

0.0015 CH3OH

0.5934 C5H12O

0.0119 C4H10O

0.0363 C2H6O

0.0268 H2O

S17 = 40.321 kgmole/hr

0.0006 C4H8

0.8646 iC4H10

0.0099 nC4H10

0.0037 CH3OH

0.0249 H2O

0.0962 C2H6O

S16 = 66.585 kgmole/hr

0.9528 C5H12O

0.0191 C4H10O

0.0279 H2O

0.0002 CH3OH

S 21 = 39.166 kgmole/hr

0.0007 C4H8

0.8901 iC4H10

0.0102 nC4H10

0.0991 C2H6O

S 20 = 12.029 kgmole/hr

1 H2O

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

S15 S16 S17

ComponentMW

kg/kgmole

Molar

flow

kgmole/hr

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)C4H8

iC4H10

n C4H10

CH3OH

C5H12O

C2H6O

C4H10O

H2O

56

58

58

32

88

46

74

18

0.026

34.86

0.4

0.16

63.44

3.88

1.274

2.866

1.456

2021.88

23.2

5.12

5582.72

178.48

94..276

51.588

-

-

-

0.011

63.44

-

1.274

1.860

-

-

-

0.352

5582.72

-

94..276

33.48

0.026

34.86

0.4

0.003

-

3.88

-

0.013

1.456

2021.88

23.2

4.768

-

178.48

-

18.108

Total 106.906 7958.72 66.585 5710.828 40.321 2247.892

7.6 LIQIUD –LIQUID EXTRACTION

83

Page 84: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S18 = 40.321 kgmole/hr

0.0006 C4H8

0.8646 iC4H10

0.0099 nC4H10

0.0037 CH3OH

C2H6O

0.0249 H2O

S23 = 13.184 kgmole/hr

0.0113 CH3OH

0.9887 H2O

S24 = 13.185 kgmole/hr

0.0113 CH3OH

0.9887 H2O

S26 = 0.407 kgmole/hr

0.146 CH3OH

0.260 H2O

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

0.0962

Input OutputS18 S20 S21 S23

ComponentMW

kg/kgmole

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)C4H8

iC4H10

n C4H10

CH3OH

C5H12O

C2H6O

C4H10O

H2O

56

58

58

32

88

46

74

18

0.026

34.86

0.4

0.149

-

3.88

-

1.006

1.456

2021.88

23.2

4.768

-

178.48

-

18.108

-

-

-

-

-

-

-

12.029

-

-

-

-

-

-

-

216.522

0.026

34.86

0.4

-

-

3.88

-

-

1.456

2021.88

23.2

-

-

178.48

-

-

-

-

-

0.149

-

-

-

13.035

-

-

-

4.768

-

-

-

234.63Total 40.321 2247.892 12.029 216.522 39.166 2225.016 13.184 239.398

7.7 DISTILLATION COLUMN

84

Page 85: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S3

Liquid-

liquid extractionS11

S17 S18

S25 = 12.778 kgmole/hr

1 H2O

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

S24 S25 S26

ComponentMW

kg/kgmole

Molar

flow

kgmole/hr

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)C4H8

iC4H10

n C4H10

CH3OH

C5H12O

C2H6O

C4H10O

H2O

56

58

58

32

88

46

74

18

-

-

-

0.149

-

-

-

13.035

-

-

-

4.776

-

-

-

234.63

-

-

-

0.003

-

-

-

12.775

-

-

-

0.096

-

-

-

229.95

-

-

-

0.146

-

-

-

0.260

-

-

-

4.680

-

-

-

4.685

Total 13.185 239.411 12.778 230.046 0.407 9.365

7.8 OVERALL REACTION SYSTEM, FLOW DIAGRAM

85

S9

Catalytic reactor

Reactor

Distillation column

Reactor

Separator

Distillation column

Liquid –

liquid extraction

Page 86: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S10S2 S12 S15

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Overall mass balance is shown below:

Input = output

InputS4 S13 S20

Molar flow

kgmole/hr

Mass flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass flow

(kg/hr)5800 2278.848 216.522

Total input 8295.37

OutputS10 S16 S26 S21

Molar flow

(kgmole/hr

)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)

Molar flow

(kgmole/hr)

Mass

flow

(kg/hr)129.48 5710.828 230.046 2225.016

Total

output8295.37

7.6 SCALE-UP FACTOR

Determination of the scale-up factor for the end product (MTBE)

With a basis 100 kgmole/hr of feed at stream S2, the product at stream S12 acquired is

5658.934 kg/hr.

This amount if converted to kg/yr, by conversion unit,

5582.72kg/hr * 7920 hr/yr = 44.215142 * 106 kg/yr of MTBE

Targeted production of MTBE = 300 X106 kg/yr (300,000 metric tonnes/yr)

86

Page 87: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

∴ Therefore, the scale-up factor = Targeted Amount Actual Amount

= 300,000 x10 3 kg/yr 44.8188 x106 kg/yr

= 6.785005854

≈ 6.785

To determined whether the scale-up factor can proceed or not,

Target amount = Actual Production x Scale-up factor

= 44.215 x 106 x 6.785

= 299.9997385 x106

≈ 300 x106 kg/yr at stream S14

Therefore, the scale-up factor of 6.785 is acceptable for this process.

CHAPTER 8

ENERGY BALANCE

8.1 ENERGY EQUATION

The equation that we used to calculate the power Q or W at each equipment is:

87

Page 88: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Q – W = ∆HR + (-∆Hin) + (∆Hout) + (∆KE) + (∆PE)

To calculate ∆H, first we need to find the Cp values for every component in each of the

stream. To find the Cp values, we need to use this equation to find the values of Cp

CPo = a + bT + cT2 + dT3

The values of a, b, c and d are taken from Appendix D, Coulson and Richardson

Chemical Engineering, Volume 6. If the temperature and pressure is more than the

critical temperature and pressure of the component, we need to find the (Cp – Cpo) for

that specific component. But as for all of our temperatures and pressures none of them

exceed the critical temperature and pressure; we need not to find the (Cp – Cpo).

To find the value of ∆H, we use this equation:

∆H = ∫T2

T1 PC dT x (n)

Should there is any reaction in the process; we need also to find the values of ∆HR

which takes place in the equipment. The equation, which we used to find ∆HR is:

∆HR = (∆ĤF product - ∆ĤF reactant) x n

and if the equipment has ∆KE and ∆PE, we also need to calculate the values by using

this equation:

∆KE = 0.5 m(vout2 - vin

2)

∆PE = mg x (zout – zin)

so, after we have calculated all the values of the energy for each and every of the

stream, we then can calculate the value of Q or W.

And for this sample of calculations, listed are the values of constants in the ideal gas

heat capacity equation based on R. K Sinnot, Coulson & Richardson, Chemical

Engineering, Volume 6, Third Edition, Butterworth Heinemann:

88

Page 89: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S2 T = -150C P = 750 Kpa (liquid) S1 T = -180C P = 450 Kpa(Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 8.1 Table of Constant in the Ideal Heat Capacity

Component a b c d Delta HF

kJ/kmol.K kJ/kmol

C5H12O 2.53 5.14 x 10-1 -2.60 x 10-4 4.30 x 10-8 -292990CH3OH 2.12 x 101 7.09 x 10-2 2.59 x 10-5 -2.85 x 10-8 -201300

H2O 32.243 1.93 x 10-3 1.06 x 10-5 -3.60 x 10-9 -242000C4H8 -2.994 3.53 x 10-1 -1.98 x 10-4 4.46 x 10-8 -130

i-C4H8 16.052 2.8043 x 10-1-1.091 x 10-49.098 x 10-9 -16900i-C4H10 -1.39 3.85 x 10-1 -1.85 x 10-4 2.90 x 10-8 -134610C4H10O -4.86 x 101 7.17 x 10-1 -7.08 x 10-4 2.92 x 10-7 -312630n-C4H10 9.85 3.31 x 10-1 -1.11 x 10-4 -2.82 x 10-9 -126.23(CH3)2O 1.70 x 101 1.79 x 10-1 -5.23 x 10-5 -1.92 x 10-9 -184180

H2 2.71 x 101 9.27 x 10-3 -1.38 x 10-5 7.65 x 10-9 0

8.2 ENERGY BALANCE: SAMPLE OF CALCULATIONS

(Methods of calculations are based on, Coulson & Richardson, Chemical Engineering,

Volume 6, page 78).

8.2.1 P-100 (Pump 1)

Calculations are based on Yunus A. Cengel, Micheal A. Boles, Thermodynamics:

An Engineering Approach, WCB/Mc Graw-Hill, 1989, page, 354-355.

Assumptions:

1. Steady operating conditions exist

2. Kinetic and potential energy negligible

3. The process is to be isentropic

Specific volume:

Isobutane = 0.255 m3/mol

n-butane = 0.263 m3/mol

89

Page 90: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S2 S3 T = -15 oC T = 117 oC P = 750Kpa P = 450Kpa (Liquid) (Gas)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(Data of these specific volumes are based on Coulson & Richardson, Chemical

Engineering, Volume 6, Third Edition, Butterworth Heinemann, page 947)

Isobutane

0.255m3/mol x 1000mol/kmol x 1kmol/58kg = 9.11 m3/kg

n-butane

0.263m3/mol x 1000mol/kmol x 1kmol/58kg = 4.53 m3/kg

Vavg = (9.11 + 4.53) m3/kg / 2 = 6.82 m3/kg

(Which remains essentially constant during the process)

22365.62kW/hr80516238kJ

39353kg/hrx2046kJ/kg

kg2046.00kJ/

6.82(300)

)J/1kpa.m450)kpa(1k/kg(7506.82m

)P(PV

VdpW

33

121

2

1

in

==∴

==

−=

−=

=∴ ∫

8.2.2 E-100 (Heat Exchanger 1)

Stream 2

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H10 675.786 -1.35 x105 298 258 -690.04n-C4H10 2.714 -1.26 x105 298 258 -2.81

90

Page 91: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

∑ ∆H =

-692.86

Stream 3

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H10 676.786 -1.35 x105 298 390 1902.85n-C4H10 2.714 -1.26 x105 298 390 7.66

∑ ∆H =

1910.51

Sample of calculations for i-C4H10 at stream 3

∆H = ∫T2

T1 PC dT x (n)

∫T2

T1 PC dT = ∫ +++T2

T1

32 dTcTbTa

=

−+−+−+−4

)Td(T

3

)Tc(T

2

)Tb(T)Ta(T

412

312

212

12

4

4)298-390(910952.28

3

3)298-390)(410846.1(

2

2)298-390(210473.38)298390)(390.1(

×+

×+

×+−=

= 10100 kJ/kmol

∆H = 10100 kJ/kmol x 675.786 kmol/hr

= 6825438.6 kJ/hr

= 1902.85 kW (for i-C4H10)

And as for n-C4H10, the ∆H = 7.66 kW

So ∑ ∆H = 1910.51

Energy balance,

91

Page 92: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S3 S4T = 117 oC T = 250 oCP = 450 kPa P = 325 kPa

(Gas) (Gas)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Q = ( ∑ H)out – ( ∑ H)in

= 1910.51- (-692.86)

= 2603.37kW

Steam flowrate, Q = mCpΔT

Cp of isobutane, 2155 J/kg oC (Elementary Principles of Chemical Processes, W.

Rousseau et. al)

9.152g/s

C(-15))-(117 x C2155J/g

J/s 2603370

TCp

Q m

oo

=

=

∆=

Therefore the supply of steam flow rate required is 9.152 g/s.

8.2.3 E-101 (Heat Exchanger 2)

Stream 3

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H10 676.786 -1.35 x105 298 390 1902.85n-C4H10 2.714 -1.26 x105 298 390 7.66

∑ ∆H =

1910.51

Stream 4

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H10 676.786 -1.35 x105 298 523 5356.57n-C4H10 2.714 -1.26 x105 298 523 21.46

92

Page 93: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

∑ ∆H =

5378.03

Sample of calculations for i-C4H10 at stream 4

∆H = ∫T2

T1 PC dT x (n)

∫T2

T1 PC dT = ∫ +++T2

T1

32 dTcTbTa

=

−+−+−+−4

)Td(T

3

)Tc(T

2

)Tb(T)Ta(T

412

312

212

12

4

4)298-523(910952.28

3

3)298-523)(410846.1(

2

2)298-523(210473.38)298523)(390.1(

×+

×+

×+−=

= 28500 kJ/kmol

∆H = 28500 kJ/kmol x 675.786 kmol/hr

= 19259901 kJ/hr

= 5349.97 kW (for i-C4H10)

And as for n-C4H10, the ∆H = 21.46 kW

So ∑ ∆Hout = 5371.43kW

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= 5371.43- (1910.51)

= 3460.92kW

Steam flowrate, Q = mCpΔT

93

Page 94: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S5 Air Out

S4T=250oCP=325kPa S6(gas) Air In

S7T=180oCP=110kPa(Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Cp of isobutane, 2155 J/kg oC (Elementary Principles of Chemical Processes, W.

Rousseau et. al)

12.17g/s

C118)-(250 x C2155J/g

J/s 3460920

TCp

Q m

oo

=

=

∆=

Therefore the supply of steam flow rate required is 12.17 g/s.

8.2.4 R-101 (Snamprogetti Fluidized Bed Reactor)

Stream 4

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H10 676.786 -1.35 x105 298 523 5356.57n-C4H10 2.714 -1.26 x105 298 523 21.46

∑ ∆H =

5378.03

Stream 7

94

Page 95: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H8 237 -1.30 x10-1 298 453 1056.59i-C4H10 2.71 -1.35 x105 298 453 13.82n-C4H10 439 -1.26 x105 298 453 2236.41

H2 439 0.00 298 453 549.84

∑ ∆H =

3856.66To calculate the value of ∆HR:

1) i-C4H10 →C4H8 + H2

so,

∆ĤR = (∆ĤF C4H8) + (∆ĤF H2) -(∆ĤF i-C4H10)

= (-130) + (0) – (-134610)

= 134480 kJ/kmol

therefore,

∆HR = (∆ĤR kJ/kmol x 236.53 kmol/hr)

= (134480 kJ/kmol x 236.53 kmol/hr)

= 31808554.4 kJ/hr

= 8835.71 kJ/s

= 8835.71 kW

Although there is stream flow, but the ∆KE is too small and negligible and there is also

now work so, W is zero and as for the ∆PE, the value is neglected, as it is also too

small.

Now we calculate the value of Q,

Q – W 0= ∆HR + (-∆Hin) +(∆Hout) +∆KE 0+ ∆PE0

Q = ∆HR + (∆Hout) - (∆Hin)

Q = 8835.71 + (1980.66) - (3856.66)

Q = 6959.71kW (heat have been absorbed)

8.2.5 C-100 (Compressor 1)

95

Page 96: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S7 S8T = 1800C T = 1930C P = 110 Kpa P = 120 Kpa (Gas) (Gas-liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

T7 = 453K T8 =?

P7 = 1.1 bar P8 = 1.2 bar

T4 = 453K, P4 = 1.1 bar, P8 = 1.2 bar is based on the literature review of process

Snamprogetti fluidized bed.

By assuming polytropic and ideal gas condition:

T7= T6(P7/P6)m (Coulson & Richardson, Chemical Engineering, Volume 6, page 85)

m = α – 1/ αEp α = CPmean/CV = CPm/CPm – R

Where R = 8.314 kJ/kmol.K

For hydrogen, a = 27.143, b = 97.38 x 10-4, c = -1.31 x 10-5, d = 76.451 x 10-10

CPHydrogen = kJ/kmol.K16200dTcTbTa1000K

453K

32 =+++∫For butene, a = -2.994 , b = 3.53 x 10-1 , c = -1.98 x 10-4 , d = 4.46 x 10-8 ,

CPbutene = kJ/kmol.K89400dTcTbTa1000K

453K

32 =+++∫For Isobutane, a = -1.39 , b = 3.85 x 10-1 , c = -1.85 x 10-4 , d = 2.90 x 10-8 ,

CPisobutane = kJ/kmol.K103000dTcTbTa1000K

453K

32 =+++∫For n-butane, a = 9.85 , b = 3.31 x 10-1 , c = -1.11 x 10-4 , d = -2.82 x 10-9,

CPn-butane = kJ/kmol.K103000dTcTbTa1000K

453K

32 =+++∫

)453466(

)etanbun,CpetanCpisobubutene,CpHydrogen,Cp(25.0Cpmean

−−+++=

ol.K167.5kJ/km4531000

103000)103000894000.25(16200 =−

+++=

So , α = CPm/CPm – R = 167.5/(167.5-8.314) = 1.07

96

Page 97: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S8 S9 T = 193oC T = 530C P = 120 Kpa P = 100 Kpa(Liquid) (Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

To find Ep(efficiency),

Flow rate =0.5

1x

273

453x22.4x

3600s

l1117.76kmo

s/m08.23 3=

From Figure 3.6, Coulson & Richardson, Chemical Engineering, Volume 6, page 83,

Ep = 75%

m = α – (1/ αEp) = 1.07-(1/1.07 (0.75) ) = 0.3690

To determine T6,

T8 = T7(P8/P7)m = 453(1.2/1.1)0.3690 = 466.83K (193oC)

Tc and Pc for H2, isobutene, isobutane and n-butane, Tc = 417.07K, Pc = 38.17 bar

Trmean = (T7 + T8)/2Tc = (453+ 466.83K)/2(417.07) = 1.10 K

Prmean = (P5 + P6)/2Pc = (1.1+1.2)/2(38.17) = 0.030 bar

From Figure 3.8, Compressibility factors (Coulson & Richardson, Chemical

Engineering, Volume 6, page 87).

Z = 1.00

Then find n, n = 1/(1-m) = 1/(1-0.3456) = 1.53

Polytropic work = zRT1(n/n-1)x((P1/P2)(n-1/n) – 1)

=

1

1.1

2.1x)

53.0

53.1)(453)(314.8(00.1

53.1

53.0

= 332.69 kJ/kmol

Actual work = Polytropic work / Ep

= 332.69 /0.75

= 443.60 kJ/kmol

Compressor power = 443.60 kJ/kmol x 1117.76 kmol/hr x 1hr/3600s

= 137.73 kW

Therefore the compressor power required to increase the pressure from 1.1 bar to 1.2

bar is 137.73kW.

8.2.6 E-102 (Cooler 1)

97

Page 98: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sample of Calculation for Cooler 1

Stream 8

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C4H8 4.39x1002 -1.69x10-4 298 466 2155.41i-C4H10 2.37x102 -1.35x105 298 466 1323.43n-C4H10 2.71x100 -1.26x105 298 466 15.15

H2 4.39x102 0.00 298 466 596.20

∑ ∆H =

4090.20

Stream 9

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H8 6.47x101 -1.69x104 298 326.3 47.45i-C4H10 3.49x 101 -1.35 x104 298 326.3 27.84n-C4H10 4.00x101 -1.26 x105 298 326.3 0.32

∑ ∆H =

75.61

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= 75.61– 4090.20

= -4014.59 kW (heat is being released to the surrounding)

Steam flowrate, Q = mCpΔT

98

Page 99: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Cp of pure water, 4.184 J/g oC (Elementary Principles of Chemical Processes,

W.Rousseau et. al)

g/s 6869.36

C53.3)-(193 x C4.184J/g

4014590J/s

TmCp

Q m

oo

=

=

∆=

Therefore the supply of steam flow rate required is 6869.36 g/s.

8.2.7 V-100 (Separator)

Sample of Calculation for Hydrogen Splitter Vessel

Stream 9

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C4H8 2.37x102 -1.69x104 298 326.3 166.03

i-C4H10 2.71x102-

1.35Ex105 298 326.3 2.17n-C4H10 4.39x102 -1.26x105 298 326.3 353.50

H2 4.39x102 0.00 298 326.3 99.88

S10 T = 53.3oC P = 90 kPa (gas)

S9T= 53.3oCP= 100kPa(liquid-gas)

S11T=53.3oCP=100kPa

99

Page 100: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S11 T = 53.3oC

P = 2000kPa(liquid)

S14 T = 27oC

P = 100kPa(liquid)

S15T = 101oC

P = 2000kPa(liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

∑ ∆H =

621.57

Stream 10

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

H2 4.39x102 0.00 298 326.3

∑ ∆H =

99.88

Stream 11

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C4H8 439.26 -16910 298 326.3 321.92i-C4H10 236.53 -134610 298 326.3 188.89n-C4H10 2.71 -126230 298 326.3 2.18

∑ ∆H =

512.99Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= (512.99)-(621.57+99.88)

= -208.46 (heat is being released to the surroundings)

8.2.8 R-102 (MTBE Reactor)

100

Page 101: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The pressure increases from 100kPa to 2000kPa. As there is a heat exchanger (heater)

in the MTBE reactor.

Stream 11

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C4H8 439.26 -16910 298 326.3 321.92i-C4H10 236.53 -134610 298 326.3 188.89n-C4H10 2.71 -126230 298 326.3 2.18

∑ ∆H =

512.99

Stream 14

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

CH3OH 4.84x102 -2.01x104 298 300 11.81H2O 1.76 -2.42x105 298 300 -4.79

∑ ∆H =

7.02

Stream 15

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C5H12O 4.30x102 -2.93x105 298 374 1339.10CH3OH 1.09 -2.01 x105 298 374 1.07

101

Page 102: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

H2O 1.94 -2.44 x105 298 374 13.94i-C4H8 0.176 -0.123 298 374 0.35i-C4H10 2.37x102 -1.35 x105 298 374 539.59C4H10O 8.64 -3.13 x105 298 374 22.49n-C4H10 2.71 -1.26 x105 298 374 6.22(CH3)2O 26.3 -1.84 x105 298 374 39.56

∑ ∆H =

1962.32

Q = ( ∑ H)out – ( ∑ H)in

= 1962.32 – 7.02 – 512.99

= 1442.31 kW

To calculate the value of ∆HR:

1.) C4H8 + CH3OH C5H12O

2.) 2CH3OH C2H6O + H2O

3.) C4H8 + H2O C4H10O

so,

∆ĤR 1 = (∆ĤF C5H12O) - (∆ĤF CH3OH) + (∆ĤF C4H8)

= (-292990) – ((-201300) + (-130))

= -91820 kJ/kmol

∆ĤR 2 = (∆ĤF C2H6O) + (∆ĤF H2O) -(2 ∆ĤF CH3OH )

= (-242000) + (-184180) – (2 x -201300)

= -23580 kJ/kmol

∆ĤR 3 = (∆ĤF C4H10O) – (∆ĤF H2O) -(∆ĤF C4H8)

= (-312630) - (-184180) – (-130)

= -128270 kJ/kmol

Therefore,

∆HR = (∆ĤR 1kJ/kmol x (63.44kmol/hr) + (∆ĤR 2kJ/kmol x 0.039kmol/hr) +

(∆ĤR 3kJ/kmol x 0.624kmol/hr)

=(-91820kJ/kmolx63.44kmol/hr)+(-23580kJ/kmolx0.039kmol/hr) +

102

Page 103: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S13 T = 270C

P = 115 Kpa (liquid) S12 T = 270C P = 110 Kpa(Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(-128270 kJ/kmol x 0.624kmol/hr)

= -5906020.9 kJ/hr

= -1640.56 kW

Although there is stream flow, but the ∆KE is too small and negligible and there is also

now work so, W is zero and as for the ∆PE, the value is neglected, as it is also too small

Now we calculate the value of Q

Q – W 0= ∆HR + (-∆Hin) +(∆Hout) +∆KE 0+ ∆PE0

Q = ∆HR + (-∆Hin) +(∆Hout)

Q = -1640.56 + 1442.31 = -198.25 kW

8.2.9 P-101 (Pump 2)

Calculations are based on Yunus A. Cengel, Micheal A. Boles, Thermodynamics: An

Engineering Approach, WCB/Mc Graw-Hill, 1989, page, 354-355.

Assumptions:

4. Steady operating conditions exist,

5. Kinetic and potential energy negligible

6. The process is to be isentropic

Specific volume:

103

Page 104: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S13 S14T= 27oC T= 27oCP=115kPa P= 115kPa(liquid) (liquid)

S29 T=27oC

P=130kPa (liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

methanol = 0.118 m3/mol

(Data of these specific volumes are based on Coulson & Richardson’s)

Methanol

0.118m3/mol x 1000mol/kmol x 1kmol/32kg = 3.6875 m3/kg

Vavg = 1.78 m3/kg

Which remains essentially constant during the process

kW 79.19 J/hr285080.63k

kg/hr15462x18.44kJ/kg

kJ/kg44.18

)J/1kpa.m110)kpa(1k/kg(1153.6875m

)P(PV

VdpW

33

121

2

1

in

==∴

=−=

−=

=∴ ∫

8.2.10 M-101 (Mixer)

Stream 13

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

CH3OH 4.83 x102 -2.01 x102 298 300

∑ ∆H =

11.79

104

Page 105: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S15 T = 1010C T = ?0C P = 2000 kPa P = 450 Kpa (liquid) (Gas-liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Stream 29

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

CH3OH 9.91 x101 -2.01 x105 298 300 0.02

H20 1.76 -2.42 x105 298 300 0.03

∑ ∆H =

0.06

Stream 14

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

CH3OH 4.84 x105 -2.01 x105 298 300 11.81

H20 1.76 -2.42 x105 298 300 0.03

∑ ∆H =

11.84

Energy balance = out - in

Q = ( ∑ H)out – ( ∑ H)in

= 11.84 – 0.06 – 11.79

= 0.04 kW

8.2.11 EX-100 (Expander 1)

T15 = 453K T16 =?

P15 = 2 bar P16 = 0.45 bar

105

S16

Page 106: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

By assuming polytropic and ideal gas condition:

T16= T15(P16/P15)m (Coulson & Richardson, Chemical Engineering, Volume 6, page 85)

m = α – 1/ αEp α = CPmean/CV = CPm/CPm – R

Where R = 8.314 kJ/kmol.K

For MTBE, a = 2.533 , b = 51.372 x 10-2 , c = -2.59 x 10-4 , d = 43.04 x 10-9 ,

CPMTBE = kJ/kmol.K151000dTcTbTa1000K

374K

32 =+++∫For TBA, a = 3.266 , b = 41.80 x 10-2 , c = -2.242 x 10-4 , d = 46.85 x 10-9 ,

CP(TBA) = kJ/kmol.K126000dTcTbTa1000K

374K

32 =+++∫For DME, a = 17.015 , b = 19.907x 10-2 , c = -5.23 x 10-5 , d = -1.918 x 10-9 ,

CP(DME) = kJ/kmol.K70700dTcTbTa1000K

374K

32 =+++∫For CH3OH, a = 21.152 , b = 70.924 x 10-3 , c = 25.870 x 10-6 , d = -2.852 x 10-8 ,

CP(methanol) = ol.K44900kJ/kmdTcTbTa1000K

374K

32 =+++∫For H2O, a = 27.143 , b = 92.738 x 10-4 , c = -1.381 x 10-5 , d = 76.451 x 10-10 ,

CP(water) = ol.K23500kJ/kmdTcTbTa1000K

374K

32 =+++∫For butene, a = -2.994 , b = 3.53 x 10-1 , c = -1.98 x 10-4 , d = 4.46 x 10-8 ,

CPbutene = kJ/kmol.K113000dTcTbTa1000K

374K

32 =+++∫For Isobutane, a = -1.39 , b = 3.85 x 10-1 , c = -1.85 x 10-4 , d = 2.90 x 10-8 ,

CPisobutane = kJ/kmol.K126000dTcTbTa1000K

374K

32 =+++∫For n-butane, a = 9.85 , b = 3.31 x 10-1 , c = -1.11 x 10-4 , d = -2.82 x 10-9,

CPn-butane = kJ/kmol.K113000dTcTbTa1000K

374K

32 =+++∫

)4531000(

)etanbun,CpetanCpisobubutene,Cp,Cpmethanol,CpDME,CpTBA,CpMTBE,Cp(125.0Cpmean H2

−−+++++++

=

mol.K153.37kJ/k3741000

113000)126000113000235004490070700126000000.125(1510 =−

+++++++=

So , α = CPm/CPm – R = 153.37/(153.37-8.314) = 1.06

106

Page 107: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S16 S17T = 193oC T = 64.50C P = 120 Kpa P = 100 Kpa (Liquid) (Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

To find Ep(efficiency),

Flow rate =0.5

1x

273

374x22.4x

3600s

ol53999.92km

s/m61.920 3=

From Figure 3.6, Coulson & Richardson, Chemical Engineering, Volume 6, page 83,

Ep = 85%

m = α – 1/ αEp = (1.06-1/1.06 (0.85)= 0.0665

To determine T6,

T16 = T15(P16/P15)m = 374(0.45/2.0)0.0665 = 338.68K (65.6oC)

Tc = 417.07K, Pc = 38.17 bar

Trmean = (T15 + T16)/2Tc = (374+ 228.68K)/2(417.07) = 0.723 K

Prmean = (P15 + P16)/2Pc = (2+0.45)/2(38.17) = 0.0321 bar

From Figure 3.8, Compressibility factors (Coulson & Richardson, Chemical

Engineering, Volume 6, page 87).

Z = 0.8

Then find n, n = 1/(1-m) = 1/(1-0.0665) = 1.07

Polytropic work = zRT1(n/n-1)x((P15/P16)(n-1/n) – 1)

=

1

45.0

2x)

07.0

07.1)(374)(314.8(00.1

07.1

07.0

= 4872.06 kJ/kmol

Actual work = Polytropic work / Ep

= 4872.06 /0.80

= 6090.07 kJ/kmol

Compressor power = 6090.07 kJ/kmol x 53999.12x 1hr/3600s

= 91349kW

Therefore the compressor power required to decrease the pressure from 2 bar

(2000kPa) to 0.45 bar (450kPa) is 91349kW.

8.2.12 E-103 (Cooler 1)

107

Page 108: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sample of Calculation for Cooler 1

Stream 16

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C5H12O 4.30 x102 -2.93 x105 298 466 3270.13CH3OH 5.02 -2.01 x105 298 466 11.81

H2O 1.21 x102 -2.42 x105 298 466 194.19i-C4H8 8.16 -1.69 x105 298 466 40.93I-C4H10 2.37 x102 -1.35 x105 298 466 1323.40C4H10O 6.65 x101 -3.13 x105 298 466 4.26n-C4H10 2.71 -1.26 x105 298 466 15.17(CH3)2O 1.21 x102 -1.84 x105 298 466 438.54

∑ ∆H =

5298.44

Stream 17

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C5H12O 4.30 x102 -2.93 x105 298 337.5 665.50CH3OH 5.02 x102 -2.01 x105 298 337.5 2.50

H2O 1.21 x102 -2.42 x105 298 337.5 44.96i-C4H8 8.16 -1.69 x105 298 337.5 8.45I-C4H10 2.37 x102 -1.35 x105 298 337.5 267.64C4H10O 0.665 -3.13 x105 298 337.5 0.85n-C4H10 2.71 -1.26 x105 298 337.5 3.09(CH3)2O 1.21 x105 -1.84 x105 298 337.5 91.16

∑ ∆H =

1084.15

Energy balance,

108

Page 109: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S19

P = 305 KpaT = 53.3 oC(gas)

S17 P = 450 Kpa T =64.5 oC ( liquid )

S18P = 400 KpaT = 103.3oC

( liquid )

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Q = ( ∑ H)out – ( ∑ H)in

= 1084.15– 5298.44

= -4214.29 kW (heat is being released to the surrounding)

Steam flowrate, Q = mCpΔT

Cp of pure water, 4.184 J/g oC (Elementary Principles of Chemical Processes,

W.Rousseau et. al)

g/s 7838.44

C64.5)-(193 x C4.184J/g

4214290J/s

TmCp

Q m

oo

=

=

∆=

Therefore the supply of steam flow rate required is 7838.44 g/s.

8.2.13 T-101 (Distillation Column 1)

Sample of Calculations:

R = L/D

Overall:

(NL), L = D x 1.5

109

Page 110: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 451.779 x 2.5

= 1129.45 kmol/hr

(NV), V = L + D

= 1129.45+ 451.779

= 1581.23 kmol/hr

Stream 17

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

C5H12O 4.30 x102 -2.93 x105 298 337.5 665.50CH3OH 5.02 -2.01 x105 298 337.5 2.50

H2O 1.21 x102 -2.42 x105 298 337.5 44.96i-C4H8 8.16 -1.69 x105 298 337.5 8.45I-C4H10 2.37 x102 -1.35 x105 298 337.5 267.64C4H10O 0.665 -3.13 x105 298 337.5 0.85n-C4H10 2.71 -1.26 x105 298 337.5 3.09(CH3)2O 1.21 x102 -1.84 x105 298 337.5 91.16

∑ ∆H =

1084.15

Stream 19

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 1.01E+00 -2.01 x105 298 376.3 1.03

H2O 6.83E+00 -2.42 x105 298 376.3 5.04i-C4H8 1.76E-01 -1.69 x104 298 376.3 0.38

(CH3)2O 2.63E+01 -1.84E+05 298 376.3 40.85i-C4H10 2.37E+02 -1.35 x105 298 376.3 557.49n-C4H10 2.71E+00 -1.26 x105 298 376.3 6.42

∑ ∆H =

611.21

Stream 18

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

110

Page 111: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S19 S20T = 53.3oC T = 400C P = 305 Kpa P =100 Kpa(Liquid) (Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CH5H12O 4.30E+02 -2.93 x105 298 326.3 469.97CH3OH 7.50E-02 -2.01 x105 298 326.3 0.03C4H10O 8.64E+00 -3.13 x105 298 326.3 7.82

H2O 1.26E+01 -2.42 x105 298 326.3 3.35

∑ ∆H =

481.17

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= (481.17 + 611.21)– 1084.15

= 8.23 kW

8.2.14 Cooler 2 (E-104)

Sample of Calculation for Cooler 1

Stream 19

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 1.01E+00 -2.01 x105 298 376.3 1.03

H2O 6.83E+00 -2.42 x105 298 376.3 5.04i-C4H8 1.76E-01 -1.69 x104 298 376.3 0.38

(CH3)2O 2.63E+01 -1.84x105 298 376.3 40.85i-C4H10 2.37E+02 -1.35 x105 298 376.3 557.49n-C4H10 2.71E+00 -1.26 x105 298 376.3 6.42

∑ ∆H =

611.21

Stream 20

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

111

Page 112: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S22T = 270C

P = 30 kPa (liquid)S21 T = 270C P = 25 kPa(Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CH3OH 1.01E+00-2.01 x105 298 313 0.19

H2O 6.83E+00-2.42 x105 298 313 0.96

i-C4H8 1.76E-01-1.69 x104 298 313 0.07

(CH3)2O 2.63E+01-1.84 x105 298 313 7.33

I-C4H10 2.37E+02-1.35 x105 298 313 98.29

N-C4H10 2.71E+00-1.26 x105 298 313 1.14

∑ ∆H =

107.97

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= 107.97– 611.21

= -503.24 kW

Steam flowrate, Q = mCpΔT

Cp of pure water, 4.184 J/g oC (Elementary Principles of Chemical Processes,

W.Rousseau et. al)

g/s 9043.40

C40)-(53.3 x C4.184J/g

503240J/s

TmCp

Q m

oo

=

=

∆=

Therefore the supply of steam flow rate required is 9043.40 g/s.

8.2.15 P-102 (Pump 3)

112

Page 113: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Calculations are based on Yunus A. Cengel, Micheal A. Boles, Thermodynamics: An

Engineering Approach, WCB/Mc Graw-Hill, 1989, page, 354-355.

Assumptions:

7. Steady operating conditions exist,

8. Kinetic and potential energy negligible

9. The process is to be isentropic

Specific volume:

Water = 0.056m3/mol

(Data of these specific volumes are based on Coulson & Richardson’s)

(Which remains essentially constant during the process)

Water

0.056m3/mol x 1000 mol/kmol x 1 kmol/18kg = 3.11 m3/kg

Which remains essentially constant during the process.

22.85kWkJ/hr22851

1469kg/hrx15.55kJ/kg

15.55kJ/kg

3.11(5)

)/1kpa.m25)kpa(1kJ/kg(303.11m

)P(PV

VdpW

33

121

2

1

in

==∴

==

−=

−=

=∴ ∫

8.2.16 T-102 (Extraction Column)

113

Page 114: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sample of Calculation for Extraction Column

Stream 20

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

CH3OH 1.01E+00-2.01 x105 298 313 0.19

H2O 6.83E+00-2.42 x105 298 313 0.96

i-C4H8 1.76E-01-1.69 x104 298 313 0.07

(CH3)2O 2.63E+01-1.84 x105 298 313 7.33

I-C4H10 2.37E+02-1.35 x105 298 313 98.29

N-C4H10 2.71E+00-1.26 x105 298 313 1.14

∑ ∆H =

107.97Stream 22

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

H2O 8.16E+01-2.42 x105 298 300

∑ ∆H =

1.53

S22 S23T=27oC T=40oCP=30kPa P=250kPa(liquid) (liquid)

S20T=40oCP=100kPa S25(liquid) T=27oC

P=100kPa(liquid)

114

Page 115: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Stream 23

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

i-C4H8 1.76E-01-1.69 x104 298 313 0.07

(CH3)2O 2.63E+01-1.84 x105 298 313 7.33

i-C4H10 2.37E+02-1.35 x105 298 313 98.30

n-C4H10 2.71E+00-1.26 x105 298 313 1.14

∑ ∆H =

106.83

Stream 25

Component Flowrates ∆ĤF To T, K ∆H Kmol/hr kJ/Kmol K kJ/hr

CH3OH 1.01E+00 -2.01 x105 298 300 0.02H2O 8.84E+01 -2.42 x105 298 300 1.65

∑ ∆H =

1.68

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= (106.83+1.68) – (107.97+1.53)

= -0.91 kW

8.2.17 Pump 4 (P-103)

115

S24

T = 40OC

P =

300 Kpa

(liquid)

Page 116: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Calculations are based on Yunus A. Cengel, Micheal A. Boles, Thermodynamics: An

Engineering Approach, WCB/Mc Graw-Hill, 1989, page, 354-355.

Assumptions:

1. Steady operating conditions exist,

2. Kinetic and potential energy negligible

3. The process is to be isentropic

Specific volume:

(Data of these specific volumes are based on Coulson & Richardson’s)

Specific volumes:

DME = 0.178m3/mol

Butene = 0.240 m3/mol

Isobutane = 0.255m3/mol

n-butane =0.263 m3/mol

DME

0.178m3/mol x 1000mol/kmol x 1kmol/46kg = 3.87 m3/kg

butene

0.240m3/mol x 1000mol/kmol x 1kmol/56kg = 4.29 m3/kg

Isobutane

0.255m3/mol x 1000mol/kmol x 1kmol/58kg = 9.11 m3/kg

n-butane

0.263m3/mol x 1000mol/kmol x 1kmol/58kg = 4.53 m3/kg

Vavg = (3.87 + 4.29 + 9.11 + 4.53) m3/kg / 4 = 5.45 m3/kg

Which remains essentially constant during the process

116

Page 117: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

1142.76kWkJ/hr4113932.50

kg/hrxg272.50kJ/k

g272.50kJ/k

5.45(50)

)J/1kpa.m250)kpa(1k/kg(3005.45m

)P(PV

VdpW

33

121

2

1

in

==∴

==

−=

−=

=∴ ∫

8.2.18 Pump 5 (P-104)

Calculations are based on Yunus A. Cengel, Micheal A. Boles, Thermodynamics: An

Engineering Approach, WCB/Mc Graw-Hill, 1989, page, 354-355.

Assumptions:

4. Steady operating conditions exist,

5. Kinetic and potential energy negligible

6. The process is to be isentropic

Specific volume:

Water = 0.056 m3/mol

Methanol = 0.118m3/mol

(Data of these specific volumes are based on Coulson & Richardson’s)

Water

0.056 m3/mol x 1000mol/kmol x 1kmol/18kg = 4.26 m3/kg

Methanol

0.118m3/mol x 1000mol/kmol x 1kmol/32kg = 3.6875 m3/kg

117

S26

T = 27OC

P =

150 Kpa

( liquid

)

Page 118: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S28T=530CP=100kPa(liquid)

S26T=27oCP=150kPa(Liquid)

S27T=30oCP=70kPa(liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Vavg = (4.26 m3/kg + 3.6875 m3/kg)/2

= 3.974 m3/kg

Which remains essentially constant during the process.

kW75.322kJ/hr322752.384

hr1624.32kg/x198.7kJ/kg

198.7kJ/kg

3.974(50)

)J/1kpa.m100)kpa(1k/kg(1503.974m

)P(PV

VdpW

33

121

2

1

in

==∴

==

−=

−=

=∴ ∫

8.2.19 T-102 (Distillation Column 2)

Sample of Calculations:

R = L/D

Overall:

(NL), L = D x 1.5

= 88.44 x 1.5

= 132.66 kmol/hr

(NV), V = L + D

118

Page 119: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

S28 S29T = 53oC T = 270C P = 100Kpa P = 130 Kpa(Liquid) (Liquid)

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 132.66 + 88.64

= 221.30 kmol/hr

Stream 26

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 9.91E-01 -2.01 x105 298 300 0.02

H2O 1.76E+00 -2.42 x105 298 300 -4.79

∑ ∆H =

-4.77

Stream 27

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 2.00E-02 -2.01 x105 298 300 0.00

H2O 8.67E+01 -2.42 x105 298 300 -235.48

∑ ∆H =

-235.48

Stream 28

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 1.10E-02 -2.01 x105 298 326 0.00

H2O 8.84E+01 -2.42 x105 298 326 -240.26

∑ ∆H =

-240.26Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= (-235.48+(-240.26))– (-4.77)

= -470.97 kW

8.2.20 Cooler 3 (E-105)

119

Page 120: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sample of Calculation for Cooler 1

Stream 28

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hrCH3OH 1.10E-02 -2.01 x105 298 300 0.00

H2O 8.84E+01 -2.42 x105 298 300 -240.26

∑ ∆H =

-240.26

Stream 29

Component Flowrates ∆ĤF To T, K ∆H

Kmol/hr kJ/Kmol K kJ/hr

CH3OH 9.91E-01 -2.01 x105 298 300 0.02

H20 1.76E+00 -2.42 x105 298 300 0.03

∑ ∆H =

0.06

Energy balance,

Q = ( ∑ H)out – ( ∑ H)in

= 0.06– (-240.26)

= 240.32 kW

Steam flowrate, Q = mCpΔT

Cp of pure water, 4.184 J/g oC (Elementary Principles of Chemical Processes,

W.Rousseau et. al)

g/s 2209.15

C27)-(53 x C4.184J/g

J/s 240320

TmCp

Q m

oo

=

=

∆=

120

Page 121: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Therefore the supply of steam flow rate required is 2209.15 g/s.

CHAPTER 9

121

Page 122: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

HYSYS

9.0 THE DESIGN MADE BASED ON HYSYS SIMULATION

There are two method that was used in calculating the mass balance and energy

balance for the process which is:

i) Manual calculation

ii) Hysys simulation

Hysys program was used to see whether the design could be run or not. Using

Hysys the calculation of the process was calculated automatically when the parameter

that needed was insert. Then if the parameter that was insert is logic so Hysys program

can calculated the result and the equipment can converge. If the data that was inserted

was illogical the equipment cannot converge and the calculation cannot be done.

At the back of this page show the simulation using Hysys that was converge

and include with the manual log book.

REFERENCES

Alber V.G Hahn (1970). The Petrochemical Industry – Market & Economics, USA

Mc Graw Hill Book Company. 363- 372.

122

Page 123: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Coulson & Richardson’s, Chemical Engineering Volume 6 Third Edition, Butterworth

Heinemann.

Norman N. Barish and Seymour Kaplan, Economic Analysis for Engineering and

Managerial Decision Making, Second Edition, Mc Graw Hill

Robert H. Perry and Don W. Green, Perry’s Chemical Engineering’s Handbook,

Seventh Edition, Mc Graw Hill.

Encik Mohd Napis Bin Sudin. 2003, Production of MTBE, Malaysia, Kuantan. Interview,

8 July

Puan Masri. 2003. Information of MTBE production, Malaysia, Kuantan. Interview, 28

Jun.

Lanny P. Schmidt (1998), The Engineering of Chemical Reaction, Oxford University

Press.

James, G. Speight, Baki Ozum (1985). Petroleum Refining Process, Apex

Engineering Inc. Marcell Dekkir New York.

MTBE and Oxygenates (1990), An International Marketing Guide Dewitt & Company

Incorporated 16800 Greenport park, Suite 120N Houston, Texas 77060-2386.

Page 51-62.

The 1992-1995 Worldwide Catalyst Product, Process Licensing & Service Directory-

Technical articl-1992/3. Page 9.

Annual Report 1994, Section 4. Area Summary for asia and the Pacific. Page 135-169.

Ray/Johnston (1989). Chemical Engineering Design Project, a case study approach,

volume 6. Gordon and Breach Science Publishers.

Wentz (1998). Safety, Health, And Environmental Protection, Mc Graw Hill

Companies, Inc.

Wiley (2000). Elementary Principles of Chemical Processes, John Willey & sons,

Inc.

Chemical Week June 11, 2003 Volume 165 page 31

George S. Brandy ,Henry R.Clauser & John A. Vaccari. ”Material Handbook – 4th

edition”-

Joshua D.Tayloy, Jerrey I. Steinfeld and Jefferson W.Tester “ Ind. Eng. Chem. Res

2001,40, 67-74 page 71.

Monica Bianchi & Rachl Uctas,ECN “ACN/CMR/ ECN NPRA Supplement, March 2002.

Petronas Resource Center, Tingkat 4, Menara 2, Menara Berkembar Petronas, Kuala

Lumpur City Center.

123

Page 124: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Malaysia Industrial Development Authority (MIDA), Plaza Central, K L Sentral. Kuala

Lumpur.

Pusat Informasi SIRIM Berhad. 1, Persiaran Dato’ Menteri, PO Box 7035, Seksyen 2,

40911 Shah Alam.

Jabatan Perangkaan Malaysia, Pusat Pentadbiran Kerajaan, Putrajaya.

Tiram Kimia Sdn. Bhd, Tingkat 1, Bangunan Shell, Off Jalan Semantan, Damansara

Heights, 50490 Kuala Lumpur.

http://www.Manufacturing.net/pur/index.asp

http://www.ceh.sric.sri.com/Public…html

http://ww2.cemr.wvu/edu/~wwwche/publications/project/index.html

http://www.illallc.com/engarticle.html

http://www.huntsman.com/pertochemicals/ShowPage.cfm

http://www.cmt.anl.gov/science_technology/basicci/onestep_phenol.shtml

http://www.illallc.com/engpatent3am.html

http://www.wikipedia.org/w/wiki.phtml

http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/acetone/basic_ace

http://www.atsdr.ede.gov/toxfag.html

http://www.shellchemicals.com/chemicals/products/1,1184,806,00.html

http://www.mida.gov.my

http://eneken.ieej.or.jp/en/data/pdf/142.pdf

http://www.matheson-trigos.com/mathportal/-pdfs/product/isobutane.pdf

http://www.specialgas.com/isobutane.html

http://www.gas.com.pdf/gas.pdf

http://www.boc.com/microsite/america/products/gases/mixed/isobutane.html

http://www.boc.com/microsite/america/products/gases/aps/geiger.html

http://www.airliquide.com/safety/msds/en/129-Al-

En.pdf http://www.cpchem/msds/specchem/isobutaneinstrumengradi.pdf

124

Page 125: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

DESIGN

PROJECT II

125

Page 126: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

SECTION 1

Catalytic Cracking Design

1.1 INTRODUCTION

A bed of solid particles can be fluidized by a stream of gas through it. The fluidization

of solids in a stream of gas occurs only if the gas velocity achieved a certain value

which is called minimum fluidization velocity Umf. Once the gas velocity achieved this

value, the bed expands and pressure drop across the fluidized bed remains constant

once fluidization occurred.

In this commercial fluidized-bed catalytic cracking reactor, catalysts flow up through the

reaction regeneration section in a riser type of flow regime. The over head catalyst

captured by cyclones is returned to the hopper where it is fluidized with air to recapture

any entrained hydrocarbon vapor. The catalyst was then discharged from the hopper,

down through a standpipe. The solids flow through the standpipe was controlled by

slide valve located at the base. From there, the solids went into the riser where they

are carried by stream of air to the regenerator vessel.

The regenerator operation in these plants resembled that of the reactor except for the

system’s use of air instead of oil vapor. A portion of the catalyst from the regenerated

catalyst hopper was returned to the regenerator through catalyst fresh feed

exchangers. This action controlled the regenerator temperature and served to preheat

the feed. Another bypass line from the hopper to the regenerator was used to control

the dense bed level or holdup in the regenerator. Catalyst from the regenerated

catalyst hopper flowed through a standpipe back into riser where the feed was injected.

The commercial cracking catalysts used most widely is silica-alumina. High content

catalysts are characterized by higher equilibrium activity level and surface area. These

126

Page 127: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

catalysts could be offered at a lower price. An advantage of this catalyst grade is that a

lesser amount of adsorbed, unconverted, heavy products on the catalyst were carried

over to the stripper zone and regenerator. As a result, a higher yield of more valuable

products and also smoother operation of the regenerator was achieved.

Basically the design of the fluidized bed system can be divided into several sections:

1. Reaction vessel which included:

Fluidized bed portion

Gas disengaging space or freeboard

Gas distributor

2. Solids feeder or flow control

3. Solids discharge

4. Dust separator for the exit gas

5. Instrumentation and control

6. Gas supply

Figure 1.1 : Illustration diagram of the reactor

127

Page 128: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

1.2 Estimation of diameter of reactor

The fluidized bed diameter depends on the operating gas velocity. A larger diameter is

required for a low gas velocity while for a high gas velocity, a small diameter is

required.

However the gas velocity must exceed the terminal velocity (Ut) of the particle

transport of solid particles may occur. The operating velocity should be between

minimum fluidization velocity and terminal falling velocity to maintain fluidization of

solids.

Operating gas velocity, Uo = g

gppgd

µρρ

18

)(2 −

Where dp = diameter of particle

ρ p = density of particle

ρ g = density of gases

µ = viscosity of gases

g = gravitational acceleration

so, the value of Uo = )1015.1(18

)484.11282(81.9)1080(5

26

××−×××

= - 0.388 m/s (rising)

= 0.388 m/s

Flowrate of gas stream , Q = 39353 kg/hr

= 3600484.1

39353

× m3/s

= 7.366 m3/s

The bed diameter will be depending on the area of reactor used:

Cross sectional area, A = V

Q

= 388.0

366.7

= 18.985 m2

128

Page 129: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Diameter of bed, D = πA×4

= π

985.184×

= 4.9164 m

≈ 5 m

1.3 Calculation of the Transport disengagement height, TDH

According to M. Rhodes (1998), the TDH region is considered as the region where

located above the bed surface to the top of disengagement zone. While the

disengagement zone is the region above the splash zone or region just above the bed

surface in which the upward flux and suspension concentration of fine particles

decrease with increasing in height.

There are so many correlations that can be used to find the TDH value. For this

design Amitin et al. (1968) was used.

( ) ( )0102.1

0 log2.133.785.0 UUFTDH −= (1.1)

( ) mFTDH 8740968.7 ≅=

1.4 Minimum fluidization Velocity

The minimum fluidization velocity (Umf) is determined from Ergun equation:

For Reynolds number, 0.01 < Re < 1000:

According to the Martin Rhodes (1999), Ar = g

ggpp gd

µρρρ

18

)(2 − and

µρ fpmf DU

=Re

129

Page 130: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

And ( ) 2

33Re

175.1Re

1150

εεε +−=Ar (1.2)

By rearranging the equation (1.2) above we can get the new equation for minimum

fluidization, Umf. As a result, the equation is becomes:

( ) 7.330408.07.1135Re 5.0 −+== Ard

DU

pg

fpmf

ρµ

µρ

( ) 7.3344.720408.07.11351080484.1

1015.1 5.0

6

5

−×+××

×= −

mfU

smUmf /00425.0=

1.5 Calculation for the value of terminal velocity tU

The value of tRe need to be calculated first, then the value of tU can be calculated.

The range of particle size is 65 μm to 95 μm. The mean particle size is 250 μm.

When md p61080 −×=

( )2

32

3

4Re

g

pgpgtD

gdC

µρρρ −

=

( ) ( )( )

96.227883Re

1015.1

108081.9484.11282484.1

3

4Re

2

25

362

=

××××−××=

tD

tD

C

C

From the chart of 2Re tDC and t

DC

Re vs Reynolds number, for value of

130

Page 131: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 1.1 : CDRe2 and CD/Re versus Reynold number

96.227883Re 2 =tDC the value of 3Re =t

Now from this we can calculate the value of tU , where

1

5

6

0.290599

1015.1

108484.13

Re

=

××××

=

=

msU

U

dU

t

t

g

ptgt µ

ρ

131

Page 132: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

when md p61085 −×=

( )

( ) ( )( )

5115.421775Re

1015.1

108581.9484.11282484.1

3

4Re

3

4Re

2

25

362

2

32

=

×

×××−××=

−=

tD

tD

pgpgtD

C

C

gdC

µρρρ

From the chart of 2Re tDC and t

DC

Re vs Reynolds number from figure 1.1 for value

of 5115.421775Re 2 =tDC the value of 5.3Re =t

Now from this we can calculate the value of tU , where

1

5

6

0.3190899

100.5

108554.53

Re

=

××××

=

=

msU

U

dU

t

t

g

ptgt µ

ρ

Table 1.1 : Calculation for terminal velocity in different size of dp.

132

Page 133: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Sieve

size dp,

m

Weight,

%, xi

Weight

fraction,

xi CDReT2

Reynold

number

Terminal

velocity, Vt

0.000095 3.5 0.035 161.1394175 4.5 0.3670733440.00009 7.5 0.075 137.0119672 4 0.344414495

0.000085 24 0.24 115.4217755 3.5 0.31908990.00008 44 0.44 96.22788368 3 0.29059973

0.000075 9.5 0.095 79.28933286 2.5 0.2583108720.00007 7 0.07 64.46516426 2 0.221409318

0.000065 4.5 0.045 51.61441905 1.8 0.214596724

1.6 Find the value of K i*∞

Using the correlation for estimating entrainment rates are reported in the literature. The

entrainment rate can be expressed by the following equation, as follows:

Ei = Ei∞ + (Eio -Ei∞)exp (-afh) ( 1.3)

Where Ei = entrainment rate at a point h above bed surface

af = a constant in freeboard

Ei∞ = rate of elutriation of the fines with diameter dpi above the TDH

Ei∞ = K i∞ Xi (1.4)

Where Ki∞ is the elutriation rate constant for which numerous correlations have been reported. Table 2.2 from Appendix lists various published correlations for the elutriation rate constant.

The constant, af, in equation (1.2) is independent of the bed’s composition and can be

evaluated from experimental data for Fi as a function of h. Following Chen et al. (1979),

is the entrainment rate of particles at the bed surface, where:

Eio = KoXi (1.5)

Where Ko = Elutriation rate constant at bed surface

Xi = weight fraction of the particle cut size dpiA

1.7 Find the value of Eo

133

Page 134: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

( ) 5..2

5.2

5.05.391007.3mf

g

eqmt

o UUg

Ad

E−

×=

µρ

Eo = ( ) ( )( )598.18)1015.1(

70.00425416388.0)81.9()484.1(1007.35..25

5.25.05.39

×−××

Eo = 10.676 kg/m2s

The following correlation is used to calculate the value of E i*∞ by using three different

investigators which is :

Merrick and Highley (1974)

−+=∞

25.05.0

4.10exp130mf

mft

g

i

UU

U

U

vA

U

E

ρ

Geldart et al. (1979) revised

−=∞

U

v

U

E t

g

i 4.5exp7.23ρ

and Colakyan et al (1979)

2

133

−=∞ U

vE ti

From this correlation we find that the average of the correlation for these three

investigators, shown in the table below:

134

Page 135: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 1.2 : Correlation of three investigators

Colakyan (1979)

Merrick and Highley

(1974)

Geldart et al.

(1981)Ki

*∞ Ki

*∞ Ki

*∞ Ki

*∞, average

10.27741771 2.810456563 0.008247282 4.365373858.238989106 3.115064954 0.011304929 3.7884529966.227114828 3.509080841 0.016081902 3.250759194.299839595 4.035580234 0.023907858 2.7864425622.545780992 4.76909596 0.037471784 2.4507829121.100824216 5.849694145 0.062625124 2.337714495

0.8993437 6.085514067 0.068853496 2.351237088

1.8 Calculation of solid loading

First find the value of Kih ,

s

haKEKK iioiih

2

**

kg/m 4.36537385

12)-)(2.69398E4.36537385 - 53(10.676996 4.36537385

)exp()(

=

+=

−−+= ∞∞

R = Σ Ri = Σ RmRi

( ) AKRF

Fmm

i

FiBi

∞+−=

135

Page 136: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

( ) ( )

( ) ( )

( ) ( )

( ) 98.1882.3512370893.10

0.004593.10

98.1852.3377144993.10

0.0793.10

98.1822.4507829193.10

0.009593.10

98.1822.7864425693.10

0.04493.10

98.183.2507591993.10

0.02493.10

98.1863.7884529993.10

0.07593.10

98.184.3653738593.10

0.03593.10

×+−×+

×+−×+

×+−×+

×+−×+

×+−×+

×+−×+

×+−×=

R

RR

RR

RRmBi

So the value of Rih calculated by excel is = 0.564147556 kg/s

smkg 2

Th

/0297.0

98.18

0.5641475

A

R Ei

=

=

=

Rti = Kih* A

8.98 1 82.35123708

8.98 1 52.33771449 8.98 1 22.45078291 8.98 1 22.78644256

8.98 1 3.25075919 8.98 1 63.78845299 8.98 1 4.36537385

×

+×+×+×

+×+×+×=

= 404.8578835 kg/s

Ri = Kih A. Xi

kg/s 55.90386

0.045 18.98 82.35123708

0.0718.98 52.33771449 0.09518.9822.45078291 0.4498.1822.78644256

.24018.98 3.25075919 0.07518.98 63.78845299 0.035 18.98 4.36537385

=

××××+××+××

××+××+××=

136

Page 137: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 1.3 : Data calculation to find solid loading

Mbi MRi Ki*η Rti Ri

0.004103705 0.602699773 4.36537385 82.85479568 2.8999180.009964059 1.269994045 3.788452996 71.90483787 5.3928630.03640034 3.981014237 3.25075919 61.69940943 14.807860.076031739 7.127685256 2.786442562 52.88667983 23.270140.018254549 1.505148839 2.450782912 46.51585967 4.4190070.013978087 1.099367014 2.337714495 44.36982112 3.1058870.008943974 0.707506537 2.351237088 44.62647993 2.008192

Total 0.167676452 16.2934157 55.90386

a) Solid loading unreturned = 0.029723 / 0.388

= 0.076606351kg/s

b) solid loading return = 55.90386 / 18.98

= 2.94540903 kg/s

1.9 Calculation of holding time and residence time

The outlet concentration of a plug flow reactor is related to the inlet concentration of the

reactant by the same equation as in a batch reactor with the same residence time -.

For an equilibrium reaction between A and B, is first order.

Based on studied of Khabtou, S., Chevreau, T., and Lavalley, J.C., Micropor. Mat. 3,

133 (1994), express the rate per catalyst mass instead of reactor volume.

113310785.4

75.0

35.035.01ln

175.0

75.0

92.151

1

−−−×=

−−⋅

+⋅−=

hrkgm

kmA

where x is the conversion in this process, x = ([A] 0 - [A]) / [A]0 = 0.35,

137

Page 138: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

[A] is experssed in concentration in mol/m3, K the rate mol m-3 s-1, kA in s-1.

The value K = [i-C4=]eq/[i-C4]eq = 0.75 and ST = 151.94 g.hr/m3 based on study by

Yamamoto, S. Asaoka, et al (1997).

Then from below equation given, w can find τ :

( ) AAA

A XX

k εετ −−

−=1

1ln1

τ = ( ) )065(41.065.01

1ln41.01 −

−−

τ = 2256.48/ 4.785x10-3

τ = 417574.39 hr

τ = 115.99 s

when the total holding time are calculate then the weight of the bed of fluidized bed can

be calculated. The formula used is as below:

0B

BedF

Wt =

kgW

W

Bed

Bed

795679.7761

393533600

830

=

=

1.10 Calculation for the pressure drop BP∆

The equation that can be used to calculate the pressure drop across the bed is:

138

Page 139: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

( )A

WW

pp

gBedBed

=∆−ρρ

( )( ) ( )

( ) kPaPap

p

383.4978.49382

985.181282

484.181.995679.7881.995679.78

≅=∆−

××−×

=∆−

According to Kunii and Levenspield, the pressure drop across the distributor dp∆ is

%10 from the value of pressure drop across the bed when fluidized BP∆ . So the value

of dp∆ is:

( ) ( )

( )

( ) 25035.0938.4

)382.49(%10

%10

−≅=∆

×=∆

∆−=∆

kgmkPaP

kPap

pp

d

d

Bd

According to Kunii and Levenspield (1991), to determine the number of holes in the

distributor the tRe need to be calculated first:

250344Re

1015.1

0.5388.0484.1Re

Re

5

0

=

×××=

=

t

t

g

tgt

DU

µρ

1.11 Determine the direction and flow rate of gas passing between the vessels.

139

Page 140: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Assuming that in fluidized flow the apparent weight of the solids will be supported by

the gas flow, the equation below gives the pressure gradient for fluidized bed flow:

( ) ( ) ( ) gH

Pgp ×−×−=∆− ρρε1

( ) ( ) ( )

m / Pa 7411.499

81.9484.1128242.01

=

×−×−=∆−H

P

Actual pressure gradient = ( )

mPa /360010

1089.225.3 5

=×−

Since the actual pressure gradient is well below that for fluidized flow, the standpipe is

operating in packed bed flow.

The pressure gradient in packed bed flow is generated by the upward flow of gas

through the solids in the standpipe. The Ergun equation above provides the

relationship between gas flow and pressure gradient in packed bed.

Knowing the required pressure gradient, the packed bed voidage and the particle and

gas properties, equation below can solve for IUrelI, the magnitude of the relative gas

velocity:

( ) ( ) ( ) 22

2

2!!

175.1!!

1150 rel

sv

frel

sv

Ux

UxH

P

−+

−=∆−ε

ερε

εµ

For standpipes it is to take downward velocities as positive. In order to create the

pressure gradient in the required direction, the gas must flow upwards relative to the

solids. Hence, IUrelI is negative:

IUrelI = -0.291 m/s

140

Page 141: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

From the continuity for the solid,

Solid flux, = ( ) ppU ρε−= 1A

G p

The solid flux calculated is 55.9 kg/m2s as and so

Up = 1282)41.01(

9.55

×− = 0.072715 m /s

Solids flow is downward, so Up = + 0.072715 m/s

The relative velocity, Urel = Uf - Up

Hence, actual gas velocity, Uf = - 0.291 + 0.072715

= - 0.21829 m/s (upwards)

Therefore the gas flows upwards at a velocity of 0.21829 m/s relative to the standpipe

walls. The superficial gas velocity is therefore :

U = ε Uf = -0.0895 m/s (upward )

From the continuity for the gas, mass flow rate of gas,

Mf = AU pf ρε

= -0.10431 kg/s

So, for the standpipe operate as required, 0.10431 kg/s of gas must flow from the lower

vessel to the upper vessel.

1.12 Design of cyclone

Size a cyclone separator for removing particles above 80µ m in diameter entrained in a

flue gas stream. The following information is supplied:

141

Page 142: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

α = 0.21 β

= 0.66 dp = 0.00008 m

gas volumetric flow = 1.8 m3/sparticle density = 1282 kg/m3

gas density = 1.484 kg/m3

viscosity gas = 0.0000115 Ns/mkinematic viscosity v = 0.0000278 m2/s

inlet gas velocity = 0.388 m/sspecific wall thickness δ = 5 mm

The particles are approximately round with a shape factor of 0.77

All dimensions of a cyclone of any design are selected depending on the width of inlet

duct b or on the diameter of cyclone Dc. The problem is to properly select one of these

dimensions from which the other dimensions are proportionally evaluated.

The cyclone diameter, settling velocity, gas velocity, and parameters of the suspension

to be separated are all interrelated parameters. Therefore, we select a preliminary

diameter for approximate calculations and then refine our estimate to a more exact

design.

According Nicholas P. Cheremisinoff at al. (1984), the relative dimensions of the

cyclone are specified as:

b = CDα and hin = CDβ

For the chosen cyclone α = 0.21 and β = 0.66

The continuity equation for the inlet nozzle is:

inW

Vbh sec= (1.5)

142

Page 143: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

where win is the inlet gas velocity; which for a primary cyclone operation is typically 18

to 22 m/s. Expressing b and hin in terms of diameter DC, equation above is rearranged

to solve for the cyclone diameter:

m

w

VD

inC

85.0

1866.021.0

8.15.05.0

sec

=

××=

=

For design purposes, assume a value of 0.9 m for DC.

The diameter of the discharge pipe is:

Dd = 0.58Dc = 0.58 x 0.9 = 0.52 m

The gas velocity in discharge pipe is thus:

smD

VW

dd /5.8

52.0142.3

8.14422

sec =×

×==π

Specifying a wall thickness δ = 5 mm for the gas discharge pipe, its outside diameter

will be:

mDD doutd 53.0)005.0(252.02, =+=+= δ

The width of the circular gap between the pipe and cyclone shell is:

mDD outdc 185.0265.045.0

22, =−=−=

The height of the circular gap from a spiral surface to the lower edge of discharge pipe

is:

H = 0.775 Dc = 0.775 X 0.9 = 0.7 m

The calculated dimensions of the cyclone can be checked by comparing the particle

settling time:

143

Page 144: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

oo

outdc

ww

RR =−

= ,0τ

to the residence time of gas in the cyclone:

g

av

w

nRπτ 2=

where Rc and Rd,out are the radii of the cyclone and discharge pipe, respectively; n =

number of gas rotations around the discharge pipe (we may assume n = 1.5)

The peripheral velocity of gas is:

smH

Vwg /9.13

185.07.0

8.1sec =×

==

For this cyclone, this value must be in the range of 12 to 14 m/s

The average radius of the gas rotation is :

mD

R outdav 357.0

2

185.0

2

53.0

22, =+=+=

The centrifugal acceleration (at the average radius) is:

222

/542357.0

9.13sm

R

wa

av

g ===

The separation criterion is:

2.5581.9

542 ===g

aK s

In this case, the centrifugal field in the cyclone is 55.2 times more intensive than the

gravitational.

The Archimedes number is:

144

Page 145: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Ar = g

gpdg

ρρρ

ν−

×2

3

= 25

35

)1015.1(

484.1)484.11282()1080(81.9−

××−×××

= 77.44

The settling number is:

S1 = Ar x 1 x Ks = 72.44 55.08843x

= 3999

Because 3.6 < S1 < 82,500 the flow regime through the cyclone is transitional.

Therefore, the theoretical velocity of the particles is:

( ) ( )

sm

ddw ff

/638.4

1015.1

12821042.5101022.0

22.022.0

25

333.02333.02

=

×

××××=

=

=

ρµρα

ρµρα

The particles have a shape factor ofψ = 0.77 and the gas inlet gas stream contains a

low volume of solid particles. Based on the operating conditions specified, the settling

velocity is

Ws = R ψ w = 0.77 x 4.634 = 3.568 m/s

Because the concentration of the suspension is low, we may assume R = 1

145

Page 146: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The settling time is therefore:

w

=0τ = 0.0518s

The residence time for the gas is:

9.13

5.1357.0142.322 ×××==g

avg

w

nRπτ = 0.2424 s

Since 0τ <τ the diameter of the cyclone selected is acceptable and we may now

specify the other dimensions as based on the recommended proportions.

As a final calculation for the design, we evaluate the hydraulic resistance of the

cyclone:

∆ P = 2

2

1inD wC ρ Where CD is the typical number of cyclone.

= 0.5 x 1 x 1.484 x 182

= 240.4 N/m2

1.13 Calculation for mechanical design

For mechanical design, the temperature and pressure are imperative properties in

calculate the thickness and the stress of the material. For that reason, the safety factor

also required as safeguard and determined by certain consideration such as corrosion

factor, location and process characteristic.

From Hysys data, the operating temperature inlet into the reactor is 250oC and

regenerator is 180oC. The design temperature is related to the operating temperature.

The design pressure and temperature for this reactor are showed as follow:

Reactor

1. Design Pressure

Operating pressure = 2.89 bar

= 0.289 N/mm2

146

Page 147: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

For safety reason take pressure 10% above operating pressure

Design Pressure, Pi = 0.289 N/mm2x 1.1

= 0.3179 N/mm2

Design Temp. , T = 200ºC

2. Material Construction

The material used is stainless steel (18Cr/8Ni, 304). For this material, the design stress

at 200 ºC, R.K.Sinnot (1999).

Design stress, f = 115 N/mm2

Diameter vessel, Di = 5.0 m

Tensile strength, = 510 N/mm2

3. Vessel Thickness

e = Pijf

DiPi

−2

= ( ) )3179.0()115(12

)5000)(3179.0(

= 7 mm + 4 mm

= 11 mm

From R.K.Sinnot (1999), this value should not be less than 12 mm (including 2 mm of

corrosion allowance). For vessel diameter around 5 m, this take e = 15 mm. A much

thicker wall will be needed at the column base to withstand the wind and dead weight

loads.

4. Heads and Closure

This section covers the choice of closure to be used in the design. Basically there are

two types of ends, which are domed ends. A standard torispherical heads and

ellipsoidal heads as well as the flat heads are calculated in order to select the most

economical head regarding its thickness. All the calculation is referring to the R.K.

Sinnot, Coulson and Richardson Vol.6 page 815-817.

Take, crown radius, Rc = Di = 5.0 m

147

Page 148: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Knuckle radius, Rk = 6% Rc = 0.03 m

A head of this size would be form by pressing: no joints, so J = 1.0

Cs =

+

k

c

R

R3

4

1

=

+

3.0

0.53

4

1

= 1.77

Therefore, minimum thickness:

e = ( )2.02 −− s

i

CPiJf

DiP

=( )( )

( )( ) ( )2.077.13179.011512

50003179.0

−−

= 11 mm

5. Column Weight

Dead weight of vessel, Wv

For a steel vessel,

Wv = 240 Cv Dm (Hv + 0.8Dm) t

Where,

Dm = mean diameter, m

= (Di + t)

Cv = a factor, take 1.15

Hv = height or length between tangent lines, m

t = wall thickness, m

148

Page 149: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

To get a rough estimate of the weight of this vessel is by using the average thickness,

11mm

Therefore,

Dm = 5 + 2 x 0.011

= 5.022 m

So,

Wv = 240 (1.15) (5.022) [7.6 + 0.8(5.022)] 0.011

= 177.13 N

= 0.17713 kN

Weight of insulation, WI

Assume material is Mineral wool.

ρ of Mineral wool = 130 kg/m3

thickness = 75 mm

Volume of insulation

= π x Dm x Hv x thickness of insulation

= π (5.022) (7.622) (0.075)

= 9.018967m3

Weight of insulation, WI

= Volume of insulation x ρ x g

= 9.018967 x 130 x 9.81

= 11501.89N

= 11.50189kN

Double this value to allow fittings, so weight of insulation will be = 23.004 kN

Weight of bed

149

Page 150: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Weight of bed in reactor

WB = 95679.78 x 9.81

= 938618.6 N

= 938.6186 kN

Weight of cyclone

Volume of cyclone in reactor = 2.438 m3

Weight of cylone = 2.438 x 9.81 x 1282

= 30661.31 N

= 30.661 kN

There fore,

Total weight = Wv +WI +WB + Wc

= (177.1311 + 23003.78 + 938618.6 + 30661.31)N

= 992.461 kN

For Regenerator

1. Design Pressure

Operating pressure = 2.6 bar

= 0.26 N/mm2

For safety reason take pressure 10% above operating pressure

Design Pressure, Pi = 0.26 N/mm2x 1.1

= 0.286 N/mm2

Design Temp. , T = 180ºC

2. Material Construction

The material used is stainless steel (18Cr/8Ni, 304). For this material, the design stress

at 200 ºC, R.K.Sinnot (1999).

Design stress, f = 121 N/mm2

Diameter vessel, Di = 6.5 m

150

Page 151: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Tensile strength, = 510 N/mm2

3. Vessel Thickness

e = Pif

DiPi

−2

= ( ) )286.0()121(12

)6500)(286.0(

= 8 mm + 4 mm

= 12 mm

4 Heads and Closure

This section covers the choice of closure to be used in the design. Basically there are

two types of ends, which are domed ends. A standard torispherical heads and

ellipsoidal heads as well as the flat heads are calculated in order to select the most

economical head regarding its thickness. All the calculation is by referring to the R.K.

Sinnot, Coulson and Richardson Vol.6 page 815-817

Take, crown radius, Rc = Di = 6.5 m

Knuckle radius, Rk = 6% Rc = 0.39 m

A head of this size would be form by pressing: no joints, so J = 1.0

Cs =

+

k

c

R

R3

4

1

=

+

39.0

5.63

4

1

= 1.77

Therefore, minimum thickness:

e = ( )2.02 −− s

i

CPiJf

DiP

151

Page 152: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= ( )( )

( )( ) ( )2.077.1286.012112

5000286.0

−−

= 14 mm

5. Column Weight

Dead weight of vessel, Wv

For a steel vessel,

Wv = 240 Cv Dm (Hv + 0.8Dm) t

Where,

Dm = mean diameter, m

= (Di + t)

Cv = a factor, take 1.15

Hv = height or length between tangent lines, m

t = wall thickness, m

To get a rough estimate of the weight of this vessel is by using the average thickness,

12 mm

Therefore,

Dm = 6.5 + 2 x 0.012

= 6.524 m

So,

Wv = 240 (1.15) (6.524) [8 + 0.8(6.524)] 0.012

= 285.6337 N

= 0.2856 kN

Weight of insulation, WI

Assume material is Mineral wool.

ρ of Mineral wool = 130 kg/m3

152

Page 153: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

thickness = 75 mm

Volume of insulation

= π x Dm x Hv x thickness of insulation

= π (6.524) (8) (0.075)

= 12.29745 m3

Weight of insulation, WI

= Volume of insulation x ρ x g

= 12.29745 x 130 x 9.81

= 15682.94N

= 15.68294kN

Double this value to allow fittings, so weight of insulation will be = 31.36588kN

Weight of bed

Weight of bed in reactor

WB = 75060.19 x 9.81

= 736340.5 N

= 736.3405 kN

Weight of cyclone

Volume of cyclone in reactor = 2.438 m3

Weight of cylone = 2.438 x 9.81 x 1282

= 30661.31 N

= 30.661 kN

There fore,

Total weight = Wv +WI +WB + Wc

= 0.2856 + 31.36588 + 736.3405 + 30.661

= 798.652 kN

153

Page 154: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Total weight for reactor and regenerator = 992.461 + 798.652 kN

= 1791.113 kN

6. Wind Loads

Take,

Win speed, Uw = 160 km/hr

For a smooth cylindrical column stack, the following semi-empirical equation can be

used to estimate wind pressure.

Pw = 0.05Uw2

= 0.05(160)2

= 1280 N/m2

Loading per Unit Length of column, Fw

Fw = Pw Deff]

Where,

Deff = Effective column diameter

= Diameter + 2(tshell + tinsulation )

= 6.5 + 2(12 + 75 ) x 10-3

= 6.68 m

Therefore,

Fw = 1280 x 6.68

= 8550.4 N/m

Bending Moment

Mx =2

)( 2XFw

154

Page 155: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Where,

X = Distance measure from the free end

= 8 m

Therefore,

Mx =2

)18(4.8550 2

= 1385164.8 Nm

= 1385.1648 kNm

7. Analysis of Stress

From bottom tangent line,

Longitudinal pressure stress,

σ h =t

DP effi

2

=)12(2

)6680)(286.0(

= 79.6033N/mm2

Circumferential pressure stress,

σ L =t

DP effi

4

=)12(4

)6680)(286.0(

= 39.802 N/mm2

Dead weight stress,

σ w = ttD

W

i )( +π

155

Page 156: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

=12)126500(

10113.1791 3

π

= 7.2958 N/mm2

Bending Stress,

σ b = ±

+ tD

I

M i

v 2

where,

M = total bending moment

Iv = ( )44

64 io DD −π

Iv = second moment of area

which,

Di = 6500 mm

Do = (6500+ 2(12))

= 6524 mm

so,

Iv = ( )44 6500652464

−π

= 1.3013 x 1012 mm4

Therefore,

σ b = ±

+

××

122

6500

103013.1

10008.138516412

= ± 3.47 N/mm2

The resulted longitudinal stress, σ z is:

σ z(upwind) = σ L - σ w + σ b

= 39.802 - 7.2958 + 3.47

= 35.9762 N/mm2

156

Page 157: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σ z(downwind) = σ L - σ w - σ b

= 39.802 - 7.2958 - 3.47

= 29.0363 N/mm2

8. Elastic Stability

Critical bulking stress

σ 1 = 2 x 104

mD

t

= 2 x 104

6512

12

= 36.855 N/mm2

Maximum compressive stress will occurs when the vessel not under pressure

= σ w + σ b

= 7.2958 + 3.472

= 10.768 N/mm2

This is below critical bulking stress, so acceptable.

9. Vessel Support Design (Skirt Design)

Type of support : Straight cylindrical skirt

θs : 80º

Material construction : Carbon steel

Design stress, fs : 135 N/mm2 at ambient temperature, 20ºC

Skirt height : 4.0 m

Young modulus : 200, 000 N/mm2

Therefore,

The total weight of vessel from calculation before = 1791.113 kN

Wind load,

Fw = 8550.4 N/m

= 8.5504 kN/m

157

Page 158: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Bending moment at skirt base,

Ms = Fw

( )

+2

2skirtv HH

= 8.5504( )

+2

218 2

= 1710.08 kNm

As a first trial, take skirt thickness as same as the thickness of the bottom section of

the vessel, ts = 12 mm

Bending stresses in skirt,

σ bs = ( )[ ]ssss

s

DttD

M

+π4

Where,

Ms = maximum bending moment (at the base of the skirt)

ts = skirt thickness

Ds = inside diameter of the skirt base

= 3.0 m

Therefore,

σ bs = ( )[ ])6500)(12(126500

)1000)(1000)(08.1710(4

= 4.287 N/mm2

Dead weight stress in the skirt,

σ ws = ( )[ ]sss ttD

W

+π2

Where,

158

Page 159: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

W = Total weight of the vessel and content

= 1791.113 kN

Therefore,

σ ws(test) = ( )[ ])012.0(012.05.6

1000113.17912

+××

π

= 14591753.05 N/m2

= 14.592 N/mm2

σ bs,(operating) = ( )[ ])012.0(012.05.6

1000113.1791

π

= 7295876.525 N/m2

= 7.2958 N/mm2

Thus, the resulting stress in the skirt, σ s :

Maximum σ s (compressive) = σ ws (test) + σ bs

= 14.592 + 4.287

= 18.879 N/mm2

Maximum σ s (tensile) = σ bs - σ ws (operating)

= 4.287 - 7.2958

= 0.0323 N/mm2

10. General consideration for design

Take the joint factor J as 0.85,

159

Page 160: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σ s (tensile) < fs J sin θs

σ s (compressive) < 0.125 E ss

s

D

t θsin

Where ,

fs = maximum allowable design stress for the skirt material

= 135 N/mm2

J = weld joint factor

θs = base angle of a conical skirt

E = modulus young = 200, 000 N/mm2

Therefore,

σ s (tensile) < 135 x 0.85 sin 80

0.1892 N/mm2 < 113.007 N/mm2

σ s (compressive) < (0.125)(200,000) 80sin3000

148

0.4014 N/mm2 < .1214.473 N/mm2

Both criteria are satisfied, add 2 mm for corrosion, give design thickness of 150 mm

11. Base Rings and Anchor Bolts

Assume pitch circle diameter = 5.0 m

Circumference of bolt circle = 5000π

Bolt stress design, fb = 125 N/ mm2

Recommended spacing between bolts = 600 mm

160

Page 161: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Minimum number bolt required, Nb = 600

5000 π

= 26.18

Closest multiple of 4 = 28

Bending moment at base skirt, Ms = 212.101 kNm

Total weight of vessel, W = 236.7534 kN

Area of bolt,

Ab =

−W

D

M

fN b

s

bb

41… E.1.19

=

− )1000)(046.184(

0.3

)1000)(101.212(4

)125(28

1

= 28.22 mm2

bolt root diameter,

d = π

422.28 ×

= 6 mm

Total compressive load on the base ring per unit length,

Fb =

+

ss

s

D

W

D

M

ππ 2

4

=

×+×)3(

10007534.236

)0.3(

1000)101.212(42 ππ

= 55.12 kN/m

Assuming that a pressure of 4 N/mm2 is one of the concrete foundation pad, fc

Minimum width of the base ring,

Lb = 310

1×c

b

f

F

161

Page 162: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 3

3

104

1012.55

××

= 13.78 mm

12. Feed Nozzle Sizing

Optimum duct diameter,

dopt,t = 293G0.53ρ -0.37

Where,

G = flow rate = 1.32121 x 105kg/hr

= 36.7 kg/s

ρ = density = 30.698 kg/ m3

Therefore,

Dopt = 293 (36.7)0.53 (30.698)-0.37

= 500 mm

Nozzle thickness,

t = Ps

dPs opt

+σ20

Where,

Ps = Operating pressure = 2.74945 N/mm2

σ = Design stress at working temperature = 30 N/mm2

Therefore

162

Page 163: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

t = 74945.2)30(20

)118)(74945.2(

+

= 0.2 mm

So, thickness of nozzle = corrosion allowance + 0.2 mm

= 4 + 0.2 mm

= 4.2 mm

∼ 5 mm

13. Top Product Nozzle Sizing

Optimum duct diameter,

dopt,t = 260G0.52ρ -0.37

Where,

G = flowrate = 223938.68 kg/hr

= 62.205 kg/s

ρ = density = 56.69 kg/m3

Therefore,

dopt = 226(62.205)0.50 (56.69)-0.35

= 500 mm

Nozzle thickness,

t = Ps

dPs opt

+σ20σ

163

Page 164: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Where

Ps = Operating pressure = 2.74945 N/mm2

σ = Design stress at working temperature = 30 N/mm2

Therefore

t = 74945.2)30(20

)1000)(74945.2(

+

= 2 mm

So, thickness of nozzle = corrosion allowance +2 mm

= 4 + 2

= 6 mm

∼ 6 mm

Table 1.4 : Summary of the Mechanical Design

Design Pressure

Reactor Operating Pressure 2.89 bar

Reactor Operating Temperature 160 0C

Reactor Design Pressure 3.179 bar

164

Page 165: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Reactor Design Temperature 200 0C

Regenerator Operating Pressure 2.6 bar

Regenerator Operating Temperature 150 0C

Regenerator Design Pressure 2.86 bar

Regenerator Design Temperature 180 0C

Safety Factor 0.10

Design of Domed Ends

Types Torispherical head

Crown Radius 6.5 mKnuckle Radius 0.039 mJoint Factor 1Stress Concentration Factor 1.77Minimum Thickness 14 mmCorrosion Allowance 4 mmColumn WeightDead Weight of Vessel 389 kNWeight of Bed 736.34 kNWeight of cyclone 30.66 kNWeight of Insulation 31.366 kNTotal Weight reactor and regenerator 1791.11 kNWind Pressure 1280 N/m2

Loading 8550.4 N/mBending Moment 1385.1648 kNm

REFERENCES

Cheremisinoff, Nicholas P., 1984, Hydrodynamics of Gas-Solids Fluidization, 279 - 231

Amitin et al. 1985, The Hydrodynamic of Fluidization, Powder Technology,(42): 67-78

Geldart, D ,. et al., 1979, Transition Institute Chemical Engineers, 57-269.

Dolignier J. C, Marty E., Martin G. & Delfosse L., 1998, Modelling of gaseous pollutants

emission in circulating fluidized bed of municipal refuse. Elsevier Science

Ltd(77): 1399-1409

Gregory et al, 1985, The design of distributor for gas-fluidized bed, Powder

Technology. (42): 100-145

165

Page 166: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Horio et al. 1980, The Hydrodynamic of Fluidization, Powder Technology,(42):

67-78

Sinclair, J.L. and R. Jackson, “Gas-Particle Flow in a Vertical Pipe with Particle-Particle

Interactions, AIChE J., 35, 1473-1486 (1989)

Sinclair, J.L., “Hydrodynamic Modeling”, in “Circulating Fluidized Beds”, ed. Grace,

J.R., Avidan, A.A. and T. M. Knowlton, Chapman and Hall, Great Britain (1997)

Wang, Z., D. Bai and Y. Jin, "Hydrodynamics of Concurrent Downflow Circulating

Fluidized Bed (CDCFB)", Powder Technology, 70, 271-275 (1992)

Wei, F., Wang, Z., Jin, Y., Yu, Z. and W. Chen, “Dispersion of Lateral and Axial Solids

in a Cocurrent Downflow Circulating Fluidized Bed”, Powder Technology, 81, 25-

30 (1994)

Himmelblau M. D. 1996, Basic Principles and calculation in Chemical Engineering.

Sixth edition. United States of America: Prentice Hall International, Inc.

Levinspiel O. 1999. Chemical reaction engineering. Third edition. United States of

America: John Wiley & Sons.

Rhodes, M. 1998. Introduction to particle technology. Chichester England. John Wiley

& Sons 97-130.

Sinnot, R.K. 1999.Chemical engineering volume 6. Third edition. Great Britain:

Butterworth-Heinemann.

Zhang H, “Hydrodynamics of a Gas-Solids Downflow Fluidized Bed Reactor”, Ph.D.

thesis, The University of Western Ontario (1999)

Zhang, H., Zhu, J-X., “Hydrodynamics in Downflow Fluidized Beds (2): Particle Velocity

and Solids Flux Profiles”, Chemical Engineering Science, 55, 4367-4377 (2000)

Matsen, J. M. "Some Characteristics of Large Solids Circulation Systems". In

Fluidization Technology, Keairns, D. L., Ed.; Hemisphere: New York, Vol. 2,

Chapter1 (1976)

166

Page 167: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Ouyang, S. Potter, S.E., “Consistency of Circulating Fluidized Bed Experimental Data”,

Ind. Eng. Chem. Res., 32, 1041-1045 (1993)

Wei, F., R. Xing, Z. Rujin, L. Guohua, J. Yong, “A Dispersion Model for Fluid Catalytic

Cracking Riser and Downer Reactors”, Ind. Eng. Chem. Res., 36, 5049-5053

(1997)

Yang Y.L., Y. Jin, Z.Q. Yu, Wang, Z.W., “Investigation on Slip Velocity Distribution in

the Riser of Dilute Circulating Fluidized Bed”, Powder Tech., 73, 67-73 (1992)

http://thor.tech.chemie.tu_muenchen.de/~tc2/eng/teaching/industr_chem_process/crac

king%20lecture%201.pdf

http://www.refiningonline.com/EngelhardKB/npra/NPR8851.htm

http://iglesia.cchem.berkeley.edu/ChemicalCommunications_1764_2003.pdf

http://www.caer.uky.edu/energeia/PDF/vol10-3.pdf

http://www.netl.doe.gov/publications/proceedings/96/96ps/ps_pdf/96ps3_2.pdf

http://tetra.mech.ubc.ca/CFD03/papers/paper29AF3.pdf

http://www.netl.doe.gov/products/r&d/annual_reports/2001/stpt/cfb%20operating

%20regimes%20cork.pdf

http://www.flotu.org/~weifei/twophase-ces.pdf

http://www.gtchouston.com/articles/GTC%20online%20reprint%2011-99.pdf

167

Page 168: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

SECTION 2

MULTITUBULAR FIXED BED REACTOR

2.1 CHEMICAL DESIGN

2.1.1 INTRODUCTION

168

Page 169: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Fixed bed reactors are the most important type of the reactor for the synthesis of large

scale basic chemicals and intermediates. In these reactors, the reaction takes place in

the form a heterogeneous catalyst. In addition to the synthesis of valuable chemicals,

fixed bed reactors have been increasingly used in recent years to treat harmful and

toxic substances. The most common arrangement is the multi tubular fixed bed reactor,

in which the catalyst is arranged in the tubes, and the heat carrier circulates externally

around the tubes. Fixed bed reactor for industrial synthesis are generally operated in a

stationary mode under constant operating conditions over prolonged production runs,

and design therefore concentrates on achieving an optimum stationary operation.

However, the non stationary dynamic operation mode is also great importance for

industrial operation control.

CATALYST FORM FOR FIXED BED REACTOR

The heart of fixed bed reactor and the site of the chemical reaction is the catalyst. The

processes taking place on the catalyst may formally be subdivided into the following

separate steps:

1. Mass transfer of reactants from the main body of the fluid to the gross exterior

surface of the catalyst particle.

2. Molecular diffusion /Knudsen flow of reactants from the exterior surface of the

catalyst particle into the interior pore structure.

3. Chemisorption of at least of the reactants on the catalyst surface.

4. Reaction of the surface

5. Desorption of absorbed species from the surface of the catalyst.

6. Transfer of products from the interior catalyst pores to the gross exterior

surface of the catalyst by ordinary molecular diffusion/Knudsen flow.

7. Mass transfer of products from the exterior surface3 of the particle into the bulk

of the fluid.

169

Page 170: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

For industrial use, a particle size is a compromise between the speed of the exchange

reaction (which is greater with small beds) and high flow rates (which require coarse

particles to minimize the head loss). Standard resins contain particle with diameter

from 0.3 to 1.2 mm, but coarser or finer grades are available. For the MTBE production

process, the fine sulphonic ion exchange resin particles with its size less than 1.0 mm

have to be enveloped in various conceivable shapes

The catalyst properties are as below:

Shape of Catalyst = Spheres

Diameter of catalyst (dc) = 0.6 mm (ref: Jon J.Ketta)

Effective Diameter surface d’p = 0.5mm

Bulk Density of Catalyst (ρb) = 810 kg/m3

Specific Solid Sphere surface = 34.25 m2/g

(ref:Perry’sHandbook,pg 16.10)

Voidage (εb) = 0.32 (ref:Tech Info.Buletin)

Surface Area (Sa) = 45 m2/g

Specific Surface = 0.034 m2/g

Specific Gravity = in range 1 to 1.4

Internal Void Fraction (εp) = 0.54

Molecular Weight = 98 g/mole

2.1.2 PARTICLES SOLID DENSITY

Particle solid density (ρp) can be obtained from the equation below (ref: Particle

Technology’s book):

ρp = ρb 1-εb

= 8101 - 0.32

= 1191.2 kg/m3

170

Page 171: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2.1.3 VOID VOLUME OF CATALYST

Void volume of catalyst, Vg can be determined as below:

Vg = εp

ρp (2.1)

= 0.321191.2

= 0.268 cm3/g

2.1.5 PORE RADIUS OF CATALYST

Pore radius of particle, r is the determined,

r = 2. Vg

Sa (2.2)

= 2 * 0.268 45 x 104

= 1.194 x10-5 m

2.1.6 KNUDSEN DIFFUSIVITY

Knudsen Diffusivity is given by the equation below:

Dk = 9.7 x103 r (T) 1/2 (M) (2.3)

where M = molecular weight of the catalyst

= 98 g/mole

T = operating temperature

= 393 K

Dk = 9.7 * 103 * 1.194 *10-5 *( 393)1/2

171

Page 172: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

98= 0.013 cm2/ s

The effectiveness factor is given in term of Thiele Modulus as:

η = 3 ( Φ - 1 ) (ref: Jon J.Mc Ketta)Φ2 tan h Φ (2.4)

η = 0.928 where Φ = 1.1 (ref: Perry,s Handbook)

2.1.7 REACTION RATE

The synthesis of MTBE from methanol and isobutylene catalyzed by Amberlyst-15

or similar sulphonic ion exchange resin catalyst is a reversible etherification as shown

in equation 1:

iC4H8 (isobutene) + CH3OH (methanol) C5H12O (MTBE)

k1 CH3C(CH3)=CH2(B) + CH3OH CH3C(CH3)2OCH3 (M) K2

Reaction kinetics:

According to Yang et al, the forward reaction of reaction above is first order with

respect to the isobutylene concentration and zero order with respect to the methanol

concentration, respectively, and the reverse reaction is first order with respect to the

MTBE concentration as shown below:

Table 1: Arhenius parameters of rate constant K1 and K2 for MTBE

synthesis catalyzed by Sulphonic ion exchange acidic resin catalyst. (Ref: Chem. Eng.

Journal)

172

Page 173: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

-rB = k1CB – k2CM

where: k1 = A1 exp (-E1/RT) & k2 = A2 exp (-E2/RT)

k1 = A1 exp (-E1/RT) (2.5)

= 6.5 * 105 exp (-4.74*104/ 8.314 * 326 K)

= 0.0165 / min

k2 = A2 exp (-E2/RT) (2.6)

= 1.36 * 108 exp (-7.04 * 104 / 8.314 * 326 K)

= 0.00071/ min

The main side reactions are the dimerization of isobutylene to diisobutylene, and the

hydration of isobutylene to tert-butyl-alcohol (TBA) as shown below:

2CH3C(CH3)=CH2 CH2=C(CH3)CH2C(CH3)2CH3 (DIB) (3)

CH3C(CH3)=CH2 + H2O CH3C(CH3)2OH (TBA) (4)

The kinetic study shows that reaction (3) can only take place when the addition of

methanol is unsufficient. Since the methanol addition is carefully arranged to allow the

molar ratio of methanol to isobutylene to be higher than 0.8, the reaction (3) can be

A1 A2 E1(J/mole) E2(J/mole)

6.50E+05 1.36E+08 4.74E+04 7.04E+04

173

Page 174: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

neglected. For reaction (4), the minor water in hydrocarbon and methanol feedstock is

consumed in the pre-reactor before it is fed into reactor. Therefore, reaction (4) can

also neglect. The products of the two side reaction are considered in the vapor-liquid

equilibrium calculation, whereas the reaction kinetics is not included in the calculation.

-rB = k1CB – k2CM

= k1(CBo –CBXB) – k2( MCBo –CBXB)

CB = CBo since Pi = 2000Kpa and Ti = 326 K

CBo = Pi /RT

= 73.79 mol /m3

M = CMo / CBo = 0.138

Substitute all the value, -rB = 173.8 mole/ m3hr

2.1.8 WEIGHT OF CATALYST

The weight of catalyst can be determined from the equation,

W = ∫ dX F r 2.7)

Where r = overall reaction rate

W = weight of catalyst needed for the conversion

F = mole flow rate of the feed to the reactor

Substitute all the value and the by integration, the weight of catalyst is found to be

2998 kg.

2.1.9 DETAIL DESIGN OF THE REACTOR

2.1.9.1 Heat Exchanger for Reactor

174

Page 175: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

For isothermal operation, heat may be supplied or removed continuously along with the

reaction path. In order to accomplish effective heat transfer with the packed bed, the

width of the bed must be small. In other words, isothermal reactors usually consist of a

number tube arranged as in large heat exchangers with the catalyst inside the tubes

and the cooling or heating medium outside the tubes.

2.1.9.2 Direction of the Reactant Flow

For the fixed bed reactor to be designed so that reactants remain isothermal, the rate

of heat required for the exothermic reaction must be exactly balance the heat transfer

from the heating medium. For any isothermal reaction of positive order, the reaction

rate falls as the reaction approaches equilibrium. Therefore a more rapid heating is

need at the reactant entrance than the reactant exit. Therefore the reactors have to be

designed as co-current to match the requirement and heat transfer.

2.1.9.3 Volume of Catalyst Bed

Volume of catalyst bed (Vb) = W / ρb

= 2998 810

= 3.70 m3 (2.8)

2.1.9.4 Pressure Drop in the Bed

Pressure drop is an important variable in the rate equations. The maximum allowable

pressure drop criteria below have to be concerned.

1. The resulting force must not be exceeding the crushing strength of the

particle. For the down flow bed this force created by the pressure drop is

transmitted by contacting solid to the bottom of the bed.

2. Mass velocity through the bed must be high enough to minimize interphase

gradients and assure good distribution. Incremental increases in pressure

175

Page 176: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

drop however should not exceed savings release from improved reactor

performance. In many bed systems the maximum economical pressure drop

is in the range of 3 to 5% of the total pressure.

2.1.9.5 Estimating Pressure Drop

(ΔP) = ƒ u2 ρf

L d’p (2.9)

Where ƒ = friction factor, the correlation of Ergun (1952) will be used

= [1.75 + 150 / (1-εb) / Re] (1-εb)/ εb3

Re = d’p u ρf = d’p G μf μf (2.10)

Where G is mass velocity = m/ A since m= 12.12 kg/s and G = 1.968 kg/m2s

μf = ( 0.28 E-6 + 1.001 E-3 +7.86 E-6)/3

= 3.36 E-4 kg/ms

Substitute the value, so Re = 2.928 (transition region) and ƒ = 73.75.

Since ρf = 796.57 kg/m3 and u= 0.0178x4/ πx2.82 =0.003 m/s,

(ΔP) will be 1060 N/m2

2.1.9.6 Height of Bed

From the criteria shown above, the optimum value of pressure drop is between 3 to

15% of the total pressure. Let the height of bed equals to 4 m, the pressure drop in the

bed is 4240 N/m2 which is equal to 4.2% of the operating pressure. Therefore, the

height of bed is taken as 4m

2.1.9.7 Total cross Section Area of the Tube

Total cross section area of the tube can be obtained by dividing the volume of the bed

with the height of the bed.

At = 3.70

176

Page 177: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4

= 0.925 m2 (2.11)

2.1.9.8 Tube Diameter

If the tube diameter to particle diameter ratio is less than 10, the effect of wall can

become predominate, the void fraction and thus fluid velocity near the wall become

more dominant. However, if high value of tube to particle diameter ratio is obtained, the

heating effects through the tube wall will not be efficient. Therefore, tube with the inside

diameter Di =0.1143m and thickness 0.005m is used in this reactor, where the ratio is

approximately 11.5.

The inside diameter of the tube (Di) = 0.1143 – 2 x 0.005

= 0.1043 m

The cross section of the tube is then obtained from the equation:

At = π Di 2 /4

= 0.009 m2 (2.12)

2.1.9.9 Total Number of Tubes

Total number of tube can then obtained by dividing the total cross section area of one

tube.

Nt = 0.9250.009

= 103 tubes (2.13)

2.1.9.10 Tube Arrangement

The tubes in an exchanger are usually arranged in an equilateral triangular, square or

rotated square pattern. Since the triangular pattern gives higher heat transfer rates, it is

recommended for this reactor.

177

Page 178: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2.9.1.11 Pitch of the Tube

From reference (Process Heat Transfer’s book), the pitch of the tube is recommended

to be 1.25 times of the outside tube diameter Do.

Therefore,

Pitch of the tube (Pt) = 1.25Do

= 1.25 x 0.1143

= 0.143 m

(2.14)

2.1.9.12 Bundle Diameter

The bundle diameter depends not only on the number of tubes but also can also on the

number of tube passes. For a single pass heat exchanger type reactor, the bundle

diameter can be obtained from the empirical equation base on standard tube layout as

shown:

Bundle diameter, Db = Do ( Nt)n-1

K1 (2.15)

Where n1 and K1 = constant for use in the equation above given in reference (Process

Heat Transfer’s book). For single pass, n1 and K1 is given as 2.142 and 0.319

respectively. Hence,

Db = 0.1143 x (103 / 0.319) (1/2.142)

= 1.70 m

2.1.9.13 Number of Tubes In the Centre Row

The number of tubes in the centre row is then given by equation:

Nc = Db / Pt

= 1.70/ 0.143

178

Page 179: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 11.8 or 12 tubes (2.16)

2.1.9.14 Shell Diameter

By using split ring floating head type from Fig 12.6 in Reference (Chem. Eng. Vol.6’s

book),

Ds – Db = 95.14 mm

Where Ds = Shell Diameter

Ds = 1.7 + 0.09

= 1.79 m

2.1.10 Baffles

Baffles are used in the shell to direct the fluid stream across the tubes, increase the

fluid viscosity and create turbulence so as to improve the rate of heat transfer. The

baffles used in this reactor are a common type i.e the single segmented baffles with

baffles cut 35 %.

2.1.11 Baffles Spacing

The optimum baffles spacing will usually be between 0.3 to 0.5 times of the shell

diameter. Here, it is taken as 0.3 times of the shell diameter.

Bs = 0.3 Ds

= 0.3 x 1.79

= 0.55 m say 0.6 m (2.17)

2.1.12 Number of Crosses

Number of crosses in the shell side,

179

Page 180: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Nc = L - 1Bs

= 4 (2.18)

Area for Cross Flow

As = (Pt – Do) * Ds * Bs

Pt (2.19)

= (0.143 - 0.114) * 1.79 * 0.6 0.143

= 0.218 m2

2.1.14 Shell side heat transfer and pressure drop calculation

The flow pattern in the shell of a segmental baffled heat exchanger type of reactor is

complex, and this makes the prediction of the shell side heat transfer coefficient and

pressure drop much more difficult than for the tube side. However, Kern has developed

a method base on experimental work on commercial exchangers with standard

tolerances and gives a reasonably satisfactory prediction of the heat transfer coefficient

and pressure drop for standard design.

2.1.15 Shell side Mass Velocity

Mass velocity, Gs

s m / kg 10.14 G

0.218

2.211 G

A

W G

2s

s

ss

=

=

=

(2.20)

Shell side velocity

180

Page 181: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

s / m 0.01 u

1209

10.14 u

G

u

s

s

ss

=

=

(2.21)

Shell side equivalent diameter for triangular pitch arrangement

Das = 4(Pt/2).0.87.Pt – π .D o

2 /8 π. Do/2

= 0.084 m (2.22)

Reynolds number

2505 Re

0.00034

084)(10.14)(0. Re

dG

Re ass

=

=

(2.23)

Prandtl number

12.3 Pr

0.086

.00034)(3124.5)(0 Pr

k

CP Pr

f

=

=

(2.24)

Choose buffle cut of 35%, from figure 12.30 (Coulson & Richardson’s Chemical

Engineering), we can obtained

Jf =1.3 x 10-1

181

Page 182: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Assumed that the viscosity correction is negligible

C m W / 763.2 h

0.084

)12.313)(2505)((0.086)(0. h

d

PrRejk h

o2s

1/3

s

e

3/1ff

s

=

=

=

(2.25)

Shell side pressure drop

Reynolds number

Re = 2505

From figure 12.30 (Coulson & Richardson’s Chemical Engineering),

Jf = 1.3 x 10-1

Shell side pressure drop can be calculated using equation below

( )( )( )( )

8.93kPa P

/2/L/Id/D8j P -0.14sBedf

=∆

=∆ wµµρµ

(2.26)

2.1.16 Tube side coefficient, hi

Mean temperature of the tube

182

Page 183: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

C 80 t

2

27 +53 t

2

tt t

omean

mean

21mean

=

=

+=

(2.27)

cross sectional area = π d12/ 4

= (3.142)(0.10432) / 4

= 0.009 m2

Tube / pass = 103 / 1

= 103 tube / pas (2.28)

Total flow rate area = (cross sectional area)(tube / pass)

= (0.009)(103)

= 0.927 m2

velocity, Gt = (2.211)/(0.927)

= 2.05 kg / sm2

v = 0.002 kg / ms

Ratio of L / di = 4 / 0.104 (2.29)

= 38.46

Reynolds number, Re

1000 Re

0.00034

(0.1043) )002.0( 1209)( Re

d

Re i

=

=

=µνρ

183

Page 184: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Heat transfer factor figure 12.31 (Coulson & Richardson’s Chemical Engineering),

Jh = 2 x 10-2

Prandtl number, as 12.3

12.3 Pr =

Tube side coefficient, hi can be calculated using equation below.

C m W / 393 h

0.104

000)(12.3))(0.086)(110(2x h

d

PrRekj h

oi

0.331-

i

i

33.0fh

i

=

=

=

(2.30)

Tube side pressure drop

Reynolds number, Re = 1000

From figure 12.24 (Coulson & Richardson’s Chemical Engineering),

jf = 2 x 10-1

Neglect the viscosity correction term

[ ]

[ ]

kPa 10.89 P

2

)00034.0)(1209(2.5)(4/0.104)10 x 8(52 P

2

2.5 )/)(L/d(j8N P

t

23-

t

2m-

Wifpt

=∆

+=∆

+=∆ iiµρµµ

(2.31)

2.1.17 Correction for Tube Heat Transfer Coefficient

184

Page 185: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Since the tube side heat transfer coefficient calculated is based on the inside diameter

of the tube, correction has to be done to obtain the heat transfer coefficient for outside

diameter of tube.

HO = hI . Di

Do

= 192 W/ moC (2.32)

2.1.18 Overall Heat Transfer Coefficient

Uc = HO . hS

HO + hS

= 100.1 W/ moC (2.33)

2.1.19 Reactor cooling system

mfCPf (t1 - t2) = mcCpc (t1 - t2) (2.34)

Log Mean Temperature difference (LMTD) :

TLMTD = Ti –To ln(Ti-To)/(Ti-To) (2.35)

= 45 oC

From this value can get mc = 39.63 kg/s where CPc=4220 and ti-t2 =135 oC

2.2 MECHANICAL DESIGN

2.2.1 INTRODUCTION

The mechanical design of chemical plant are of particular interest to chemical

engineers, but not usually be called on to undertake the detailed mechanical design of

185

Page 186: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

the plant, especially the reactor vessels. However, the chemical engineer will be

responsible for developing and specifying the elementary design information for the

reactor, and need to have a general appreciation of pressure vessel design to work

effectively with the specialist designer.

Therefore, the design of wall thickness, head, column support, flange joint,

reinforcement and maximum allowable pressure are considered here.

Material of construction:

In this design, reference will mainly be based on the current British Standard BS 5500

and Bs 1515 where the current addition of Bs 5500 covers vessels fabricated in carbon

steel. The most common types used in the petroleum industry are Types 304, 316,321,

and 347.Because of their inherent high temperature strength propertied and high

corrosion resistance, they are particularly suitable for use in this process, in areas of

moderate and high temperature, and where substantial resistance such as in heater

tubes, reactors, reactor effluent exchangers and piping. In this design, material of

construction: can be constructed by using carbon steel. Type 304

DESIGN STRESS

It is necessary to decide a value for the maximum allowable stress that can be

accepted in the material of construction, for example, it can withstand without failure

under standard test conditions. The nominal design strengths (allowable design stress)

for the range of materials covered are listed in BS 5500. By using carbon steel (semi

killed or silicon Killed), the design stress is given, σD as 125 N /mm2 at design

temperature.

WELDED JOINT EFFICIENCY

The strength of a welded joint will be depending on the type of joint and the quality of

the welding. The soundness of welds is checked by visual inspection and non

destructive testing (radiography).

For the reactor, it is assumed that the joint is equally as strong as the virgin plate; this

is achieved by radio graphing the complete weld length and cutting out and remarking

186

Page 187: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

any defects. Therefore, the non destructive testing is assumed to be 100% and the

joint efficiency, J is taken as 1.0.

2.2.4 CORROSION ALLOWANCE

1. Corrosion and erosion or scaling will cause material lost, so an additional thickness

of material called “corrosion allowance” must be added to be calculated wall

thickness.

MINIMUM THICKNESS OF CYLINDRICAL SECTION OF SHELL

The minimum thickness of cylindrical section of shell to resist the internal pressure can

be determined by using equation below:

e = PD DIs

2J σD - PD

= 2.0*1.82.125-2

= 0.015 m (2.36)

By adding corrosion allowance 2 mm,

e = 0.015 + 0.002m

= 0.017 m

MINIMUM THICKNESS OF DOMED HEAD

There are three types of commonly used domed head:

1. Hemispherical heads

2. Ellipsoidal heads

3. Torispherical heads

187

Page 188: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The selection of head depends on the cost and the thickness required for the head.

The design equations and charts for the various types of domed head are given in the

codes and standards (BS 5500) used in this design.

A standard dished head (torisphere) is used as first trial. The crown radius of this head

equals to the diameter of the shell, DIS. On the other hand, the knuckle radius is taken

as 6% of the crown radius. Since this type of head is formed by pressing, no joint is

needed. Therefore, the joint factor is taken as 1.

For the torispherical head, the minimum thickness of the head can be determined from

equation below:

eh = P D RC CS 2 J TD + PD(CS – 0.2) (2.37)

where Rc is the crown radius, equal to DIS in this case.

CS = stress concentration factor for torispheriical head.

It is given by equation below:

CS = 1 / 4(3 + (Rc + Rk) 1/2) (2.38)

Since Rk is 0.06 of Rc,

CS = 1 / 4 (3 + (1/ 0.06)1/2)

= 1.771

Therefore,

eh = 2.0 x1.8 x1.771 2 x 1x125 + 2.0 (1.771 - 0.2)

= 0.025 m

However, for a standard ellipsoidal head,

eh = PDDIs

2J σD - 0.2PD

= 0.014 m (2.39)

Therefore, an ellipsoidal head would probably be the most economical to be used. For

convenience, the thickness is taken to be as same of wall thickness 17 mm.

188

Page 189: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

LOADING STRESSES

2.2.7.1 Dead Weight of Loading

2.2.7.2 Dead Weight Of vessel

The major source of dead weight loads are:

1. vessel shell

2. vessel fitting : manway, nozzles

3. internal fittings: where the main item is tube

4. insulation

5. catalyst

The preliminary calculation of the approximate weight of a cylindrical vessel with

domed ends, and uniform wall thickness can be estimated from the following equation,

Wv = Cv.Л.ρm.Dm.g.(Hv + 0.8Dm)t x 10-3

Where Wv = total weight of the shell, excluding internal fitting

Cv = a factor to account for the weight of nozzles, internal

support etc.

Cv is given as 1.08 for vessels with only a few internal

fitting.

Hv = height between 2 tangent lines, 4m in this case

g = gravitational acceleration, 9.81 m/s2

t = wall thickness, mm

ρm = density of vessel material, kg/m3. by using carbon steel,

ρm = 6870 kg/m3

Dm = mean diameter of vessel

= DIs + t * 10-4

Since the wall thickness = 0.017 m

Therefore, Dm = 1.8 + 0.014

= 1.817 m

As a result, by substituting into the equation above:

Wv = 39000 N

= 39 KN

189

Page 190: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Weight of the Tubes

From BS 3059, the mass per length of tubes is equal to 13.5 kg/ m for carbon steel.

Therefore, the weight of one tube

= 13.5 x 3 x g

= 4.529 * 104 N

≈ 45 KN (2.40)

Total weight of the tubes,

Wt = 103 x 13.5 x3 x9.81

= 4.1x104

Weight of Insulation

To avoid heat loss from the surface of the shell, mineral wool is used as the insulator.

From (Chem. Eng. Vol. 6’s book),

Density of mineral wool = 130 kg/m3

Let the thickness of mineral wool = 75 mm

The approximate weight of the insulator,

Wi = 2ЛHvtiρig (2.41)

= 2 Л x3 x0.075 x30 x9.81

= 1.803 x103 N

This value should be double to allow for fittings, etc.

= 3.6 x103 N

190

Page 191: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Weight of Catalyst

Weight of catalyst, Wc = 2998 kg

= 2.998 x104 N

Total Weight

Since only 4 baffles are used in the reactor, their weight is neglected compared to

others.

W = Wv + Wi + Wt +Wc

= 39000N+ 4.1x104 N+ 3.6x103 N +2.998x104 N

= 1.1x 105 N

Wind Loading

Take dynamic wind pressure as 1300 N/m2

Mean Diameter, including insulation = 2+2(17+75) x10-3

= 2.18 m

The wind loading is then given by equation below:

Fw = Pw Dm

= 1300 x2.18 m

= 2.8 x 103 N/m (2.42)

Therefore, the bending moment at bottom tangent line can be determined from

equation below:

Mx = Fw L 2

191

Page 192: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2 (2.43)

= 2.8 x 10 3 x 4 2 2

= 2.24 x104 N

2.2.7.8 ANALYSIS OF STRESSES

Uniform thickness is used for analyzing stresses in the column. If it is found satisfactory

at the bottom of the vessel which is the highest loading point, then the entire column

structure is feasible.

At bottom tangent line, the longitudal and circumferential stresses due to pressure is

given by:

Longitudal, σL = Pi Di

4t

= 2.0 x1.84 x 0.017 (2.44)

= 53 N /mm2

Circumrerential, σh = Pi Di

4t

= 2.0 x1.82 x 0.017

= 106 N /mm2

Dead Weight Stress

The direct stress is mainly due to the weight of vessel, its contents and any attachment

which is often called the dead weight stress. The stress is compressive since it is at the

bottom of the vessel to support the direct loading.

192

Page 193: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Dead Weight stress, σW = W Л (Di + ti) * t

= 1.1 x 10 5 Л (1800 + 17) x 17 (2.45)

= 1.13 N /mm2 (compressive)

Bending Stress

The second moment of area of the vessel about the plane of bending,

Iv = Л (Do4 – Di

4) (2.46)64

Where Do = outer diameter of vessel

= Di + 2t

= 1.8 + 2 x 0.017

= 1.834 m

Iv = Л (18344 – 18004)64

= 4.0 x1010 mm4

Therefore, the bending stress is then given by equation below:

σb = ± Mx (Di /2 + t) (2.47) Iv

= ± 0.51 N/mm2

The resultant longitudal stress

σZ = σL + σW + σb

For upwind,

σZ = 53 – 1.13 + 0.51

= 52.38 N/mm2

For downwind,

193

Page 194: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σZ = 53– 1.13 - 0.51

= 51.36 N/mm2

Radial Stress

= Pi = 2.02 2 (2.48)

= 1.0 N/mm2

Since radial stress obtained is a small value and there are torsional stress in the

system, therefore the principle stress will be σZ and σh

52.38 N/mm2 51.36 N/mm2

Figure 2.1: Analysis of Stresses

194

Page 195: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Therefore, the greatest difference between the principles stresses,

σd = σh - σZ ( downward)

= 106 – 51.36

= 54.64 N/mm2

The value obtained is well bellow the maximum allowable design, 125 N/mm2.

2.2.11 CHECK ELASTIC STABILITY

The design of this vessel have to be checked to ensure that the maximum value of the

resultant axial stress does not exceed the critical value at which buckling will occur.

By applying a factor of safety of 12, the critical buckling stress gives:

σC = 2x104 (t/Do)

= 185.4 N/mm2 (2.49)

The maximum compressive stress will occur when the vessel is not under pressure,

= σW + σb

= 1.13 + 0.51

= 1.64 N/mm2

Which is well below the critical buckling stress, σC .

2.2.12 VESSEL SUPPORT

The method used to support a vessel will depend on the size, shape and weight of the

vessel; the design temperature and pressure; the vessel location and arrangement;

and the internal and external fittings and attachment. Since the reactor is a vertical

vessel, skirt support is used in this design.

195

Page 196: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

A skirt support consists of a cylindrical or conical shell welded to the base of the

vessel. A flange at the bottom of the skirt transmits the load to the foundations. The

skirt may be welded to the bottom, level of the vessel.

Skirt supports are recommended for vertical vessels as they do not imposed

concentrated loads on the vessel shells; they are particularly suitable for use with tall

columns subject to wind loading.

2.2.13 SKIRT THICKNESS

The skirt thickness must be sufficient to withstand the dead weight loads and bending

moments imposed on it by the vessel; it will not be under the vessel pressure.

The resultant stresses in the skirt will be:

σS (tensile) = σbS - σWS

and

σS (compressive) = σbS + σWS

where σbS = bending stress in the skirt

= 4Ms Л(Ds + ts) tsDs (2.50)

σWS = the dead weight stress in the skirt

= W Л(Ds + ts) ts

Where Ms = maximum bending moment, evaluated at the base of the skirt.

W = total weight of the vessel and contents

Ds = inside diameter of the skirt, at the base

ts = skirt thickness

196

Page 197: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The skirt thickness should be such that under the worst combination of wind and dead

weight loading the following design criteria are followed:

σS (tensile) < fs.J sin θs

σS (compressive) < 0.125 E (ts/Ds) sin θs

Where fs is the maximum allowable design stress for the skirt material, normally taken

at ambient temperature, 20oC.

J = weld joint factor

θs = base angle of conical skirt, 90o is used in this design

The maximum thickness should not less than 6mm.

2.2.14 HEIGHT OF THE SKIRT

The height of the skirt, Hs is taken to be 1m.

2.2.15 BENDING STRESS AT BASE OF THE SKIRT

Mbs = Fw (Hv + Hs) 21 2 (2.51)

= 2.8x 103 (4 + 1) 2 2

= 3.5 x 104 Nm

BENDING STRESS IN THE SKIRT

As the first trial, the thickness of skirt is taken to be 20 mm.

Substitute into the equation (19),

σbS = 4 x 2.24 x10 4

Л (1.9 + 0.020) 1.9x0.020

= 3.9 x 105 N/m2

197

Page 198: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σWS = 1.1 x 10 5 Л (1.9 +0.020)*0.020

= 9.1 x 105 N/m2

The maximum stress (compressive),

σS = σbS + σWS

= 3.9 x 105 N/m2 +9.1x 105 N/m2

= 1.3 x 106 N/m2

The maximum stress (tensile),

σS = σbS - σWS

= 3.9 x 105 N/m2 – 9.1 x 105 N/m2

= 5.2 x 105 N/m2 (negative)

Let the joint factor for skirt support, J = 0.85

Criteria for design,

fs.J sin θs = 125 x 0.85 xsin( 90o) (2.52)

= 10.63 * 107 N/m2

> σS (tensile) , therefore it satisfied.

Modulus Young = 200,000 N/mm2 at ambient temperature, (from Bs 5500:1998),

0.125 E (ts/Ds) sin θs = 0.125x2x105 (0.02/1.9) sin 90o

= 26.3 x 107 N/m2

> σS (compressive) , therefore it satisfied

Both criteria are satisfied, add 2mm for corrosion allowance, and give a design

thickness of 22 mm.

198

Page 199: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

BASE RING AND ANCHOR BOLT DESIGN

The loads carried by the skirt are transmitted to the foundation slab by the skirt base

ring (bearing plate). The moment produced by wind and other lateral loads will tend to

overturn the vessel. Since the reactor can be considered as the small vessel, the

simplest types, rolled angle ring are used. The preliminary design of base ring is done

by using Scheiman’s short cut method.

The anchor bolts are assumed to share the overturning load equally, and the bolt area

required is given by:

= 1 (4.Mbs – W) (2.53) Nbfb Db

Where Ab = area of one bolt at the root of the thread, mm2

Nb = number of bolts

fb = maximum allowable bolts stress, typical design = 125 N/mm2

Mbs = bending (overturning) moment at the base, Nm

W = weight of the vessel, N

Db = bolt circle diameter, m

Scheiman gives the following guide rules which can be used for the selection of the

anchor bolts.

1. bolts smaller than 25 mm diameter should not be used

2. minimum number of bolts = 8

3. use multiples of 4 bolts

4. bolts pitch should not be less than 600 mm

The base ring must be sufficiently wide to distribute the load to the foundation. The

total compressive load on the base ring is given by:

fb = (4 Mbs + W ) = 28255 N/mm (2.54) ЛDs

2 ЛDs

Where Fb is the compressive load on the base ring and Ds = skirt diameter, m

The minimum width of the base ring is given by:

199

Page 200: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Lb = fb 1 fc 103 (2.55)

Where Lb = base ring width, mm

fc = the maximum allowable fc on the concrete foundation pad,

And typically range from 3.5 to 7 N/mm2

fb = 28255 N/mm

Take the bearing pressure as 5 N/mm2, fc = 5 N/mm2

Substitute into the equation above,

Lb = 28255 5 x103

= 5.65 mm

This is the minimum width required; actual width will depend on the chair design

Actual width required= Lr + ts +50 mm

Where Lr = the distance from the edge of the skirt to the outer edge of the ring, mm

= 64 mm (from BS 4190:1967)

Therefore, actual width required = 64 + 22 +50

= 136 mm

Actual bearing pressure on concrete foundation:

f’c = 28255136 x103

= 0.21 N/mm

tb = 64 ( 3 x 0.21) ½ (2.56) 140

200

Page 201: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 4.3 mm

COMPENSATION FOR OPENING AND BRANCHES

All process vessels will have opening for connections, man ways, sight holes, hand

holes and instrument fittings. The presence of an opening weakens the shell, and gives

rise to stress concentrations. The stress at edge of a hole will be considerably higher

than the average stress in the surrounding plate. To compensate for the effect of an

opening, the wall thickness is increased in the region adjacent to the opening.

Sufficient reinforcement must be provided to compensate for the weakening effect of

opening without altering the general dilation pattern of the vessel opening.

2.2.19 COMPENSATION FOR OTHER NOZZLES

Pipe size for inlet and outlet of the reactor are all less than 10 mm, therefore, the

reinforcement area can be usually is provided by increasing the wall thickness of the

branch pipe. This already done on piping, where extra thickness is provided, thus no

compensation area needed.

2.2.20 BOLTED FLANGE JOINT

Flanged joints are used to connect pipes and instruments to vessels and from

removable vessel heads when ease of access is required. Flanges may also be used

on the vessel body, when it is necessary to divide the vessel into section for transport

or maintenance. Flanged joints are also used to connect pipes to other equipment,

such as pumps, valves.

2.2.20.1 Type of Flanges Selected

a) Welding neck Flanges

201

Page 202: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Have a long tapered lub between the flange ring and the welded joint. This gradual

transition of the section reduces discontinuity stresses between flange and branch,

and increases the strength of the flange assembly.

Welding neck flanges are suitable for extreme service conditions, where the flange

is likely to be subjected to temperature, shear and vibration loads.. For this reactor,

the welding neck flanges are suitable for use in connecting the inlet and outlet

piping of reactor.

b) Gasket

Gaskets are used to make a leak tight joint between two surfaces. It is impractical to

machine flanges to the degree of surface finish that would be required to make a

satisfactory seal under pressure without a gasket. Gasket are made from “semi plastic”

materials, which will deform and flow under load to fill the surface inequalities between

the flange faces, yet retain sufficient elasticity to take up the changes in the flange

arrangement that occur under load.

Several factors must be considered when selecting a gasket material:

1. The process condition: pressure, temperature, corrosive nature of

process fluid.

2. Whether repeated assembly and disassembly of the joint is required

3. The type of flange and flange face.

Judging from process conditions, where the operating temperature is quite high, 393K,

metal reinforced gaskets is recommended, since it have a quite good heat resistance

property.

2.2.21 Flange Face

The raised face, narrow feed flange are used for all the flanges. Where the flange has

a plain face, as for the flange faces mentioned above, the gasket is held in place by

friction between the gasket and flange surface.

202

Page 203: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

S

SUMMARY OF CHEMICAL DESIGN PARAMETERS

Reactor Design

Catalyst weight required 2998 kg

Volume of Catalyst bed 3.7 m3

Height of Bed 4.0 m

Diameter of Bed 1.817 m

Tube inside pressure drop 1.06E-4 N/m2

% of pressure drop 0.042

Tube inner diameter 0.1043 m

Total number of tubes 103 tubes

Tube arrangement equivalent triangular pitch

Tube side heat transfer coefficient 293 W/moC

Pitch of tube 0.143 m

Bundle diameter 1.70 m

203

Page 204: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Shell diameter 1.79 m

Baffles cuts 0.35

Baffles Spacing 0.6 m

Number of crosses 4

Inlet flow rate 0.647 kg/s

Inlet temperature 326 K

Outlet temperature 373 K

Shell side heat transfer coefficient 191 W/moC

Shell side pressure drop 0.557 kPa

Design overall heat transfer area 100.1 W/moC

SUMMARY OF MECHANICAL DESIGN PARAMETERS

204

Page 205: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Operating Conditions and Material of construction

Design pressure 2.0 bar

Design temperature 323 K

Material of construction Carbon Steel plate (Type 304)

Design Stress 125 N/mm2

Welded joint efficiency 1

Corrosion allowance 2 mm

Designed Column Diameter

Shell thickness 17 mm

Domed end thickness(ellipsoidal heads) 17 mm

Vessel Support (skirt)

Skirt thickness 22 mm

Skirt diameter 1.9 m

Skirt height 1 m

Base Ring and Anchor Bolt

Base ring Rolled angle rings

Minimum ring thickness 4.5 mm

Minimum base ring width 7.06 mm

Anchor bolt M24

Number of bolts 8

Bolt root diameter 21.2 m

205

Page 206: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

SECTION 3

MTBE DISTILLATION COLUMN

3.1 INTRODUCTION

Distillation is a method used to separate the components of a liquid solution, which

depends upon the distribution of these various components between a vapor

and a liquid phase. All components are present in both phases. The vapor

phase is created from the liquid phase by vaporization at the boiling point.

MTBE is our main product that needs to be separated. For individual design,

MTBE distillation column was chosen. The characteristics required in the chosen types

of distillation column are the separation objective satisfied in the column, the cost of

construction and the design of the selected distillation column.

T=64.5oC

LC

T C

T=53.3oC

T=103.3oC

C ondense r

R ebo iler

R e lie f Va lve

Figure 3.1 MTBE Distillation Column

3.2 SELECTION OF CONSTRUCTION MATERIAL

206

Page 207: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Materials chosen are based on the characteristics of the component in the distillation

column, the location and the environmental consideration of the MTBE plant. Stainless

steel 304 is used in construction of the MTBE distillation column - ‘The stainless steels

are the most frequently used corrosion resistant materials in the chemical industry’ –

Coulson & Richardson, Chemical Engineering, Volume 6, page 295.

Carbon steel is used in skirt support material and the insulation material used is

fiberglass. The selection is based on the chemical and mechanical design as stated in

Coulson & Richardson, Chemical Engineering, Volume 6. Most parameters used in

design were referred to mass, energy balance data and also data generated by

Chemical Engineering Simulation Software; HYSIS Version 3.2. Other materials

chosen were based on the British Standard BS 5500, BS4505 and BS 750.

3.3 CHEMICAL DESIGN

In the MTBE distillation column design, the McCabe-Thiele method in

determining the number of stages needed was used. The McCabe-Thiele method is

based upon representation of the material-balance equations as operating lines on the

X-Y diagram. The lines are made straight (and the need for the energy balance

obviated) by the assumption of constant molar overflow. The liquid-phase flow is

assumed to be constant from tray to tray in each section of the column between

addition (feed) and withdrawal (product) points. If the liquid rate is constant, the vapour

rate must also be constant.

Table 3.1 The Composition in Feed Stream

FEED Component T (K) Operating Op Pressure, Feed Flowrate Fraction, zi

207

Page 208: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

T (K) kPa

kmol/hr

i-C4H10 313 337.5 450 34.860 0.3261

n-C4H10 313 337.5 450 0.400 0.0037

C4H8 313 337.5 450 0.026 0.0002 DME 313 337.5 450 3.880 0.0363

CH3OH 313 337.5 450 0.160 0.0015

H2O 313 337.5 450 2.866 0.0268 MTBE 380 337.5 450 63.44 0.5934

TBA 380 337.5 450 1.274 0.0119

∑ =106.906 ∑ = 1.0000

Table 3.2 The Compositions in Top Stream

Top Component T (K)Operating

T (K)Op Pressure,

kPa Top Flowrate Yi

kmol/hr

i-C4H10 313 326.3 305 33.860 0.839760919

n-C4H10 313 326.3 305 0.400 0.009920389S16 (top) C4H8 313 326.3 305 0.026 0.000644825

DME 313 326.3 305 3.880 0.096227772

CH3OH 313 326.3 305 0.149 0.003695345

H2O 313 326.3 305 1.006 0.024949778

MTBE 313 326.3 305 1.000 0.024800972

∑ =40.321 ∑ =1.0000

Table 3.3 The Composition in Bottom Stream

Bttm Component T (K)Operating

T (K)Op Pressure,

kPaBttm

Flowrate Xikmol/hr

i-C4H10 380 376.3 400 1.000 0.015018398

MTBE 380 376.3 400 62.44 0.937748742S14

(bttm) TBA 380 376.3 400 1.274 0.019133438

CH3OH 380 376.3 400 0.011 0.000165202

H2O 380 376.3 400 1.860 0.027934219∑ =66.59 ∑ =1.0000

* The T(K) is the stream temperature, while the Operating T(K) temperature is the

temperature which should be achieved by controlling the pressures.

208

Page 209: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.3.1 DETERMINATION OF THE NUMBER OF PLATES USING McCABE-

THIELE METHOD

The components in the feed to the MTBE distillation column are i-C4H10, n-C4H10, C4H8,

DME, CH3OH, H2O, MTBE and TBA, and the feed is assumed as multicomponents

feed. By using the Hengstebeck’s and McCabe-Thiele method, the number of stages

required and the position of the feed in the MTBE distillation column can be

determined.

The determination of the plate by using McCabe-Thiele method was simply

because as explained in J.M Coulson, J.F Richardson, Chemical Engineering Volume

2, Third Edition, the Pergamon Textbook, page 429, which stated that “This method is

one of the most important concepts in chemical engineering and is an invaluable tool

for the solution of distillation column. The assumptions of constant molar overflow is

not limiting since in very few systems do the molal heats of vaporizations differ by more

than 10 percent. The method does have limitations, however, and should not be

employed when the relative volatility is less than 1.3 or greater than 5, when the reflux

ratio is less than 1.1 times the minimum, or when more than twenty-five theoretical

trays are required. In these circumstances, the Ponchon-Savarit method should be

employed”.

The vapor pressure can be determined by using the Antoine’s equation as follows:

Log10 P* = A - CT

B

+ (3.1)

With related at equilibrium, constant K,

Ki = P* x P (3.2)

And related with concentration,

209

Page 210: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Ki = xi

yi (3.3)

Where yi = concentration in vapor phase

xi = concentration in liquid phase

Calculation for the relative volatility, α ,

α = KLK / KHK (3.4)

Where KLK = Light key component

KHK = Heavy key component

In this case, MTBE is as the heavy key and i-C4H10 is as the light key components. By

using goal seek in the excel programme, the value of the bubble point at bottom

column = 103.3oC and dew point at the top column is = 53.3 oC, from the values of Ki

related to the pressure, the values of relative volatilities could be determined, listed are

values of the relative volatilities for components at the top and bottom of the distillation

column.

Table 3.4 Average Relative Volatility, α

Component Top, α Bttm, α Avg, αi-C4H10 (LK) 7.699631 5.084017 6.39182391

n-C4H10 5.654994 - 2.827496955

C4H8 6.948741 - 3.474370398

DME 14.10614 - 7.05306993

MTBE (HK) 1.00000 1.0000 1.00000

TBA - 0.149333 0.074666444

CH3OH 0.67395 0.99561 0.834780143

H2O 0.152422 0.288322 0.220371796

Calculations for the non-key flows,

Table 3.5 The Non-key Flow of the Top Stream

210

Page 211: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

TOP α i di li = di / (α i-1) Vi = li + din-C4H10 2.827497 0.4 0.218878614 0.618878614

C4H8 3.47437 0.026 0.010507724 0.036507724DME 7.05307 3.88 0.640997055 4.520997055

CH3OH 0.83478 0.149 -0.901828648 -0.75282865H2O 0.220372 1.006 -1.290358653 -0.28435865

∑ = -1.321803909 ∑ = 4.139Table 3.6 The Non-Key Flow of the Bottom Stream

BOTTOM α i bi Vi’=α ibi / (α LK-

α i )

li’ = vi’ + bi’

TBA 0.074666 1.27 0.01506000 1.2900

CH3OH 0.83478 0.01 0.001652422 0.0100

H2O 0.220372 1.86 0.066417357 1.9300∑ = 0.083127984 ∑ = 3.23

Flows of combine key,

Le = L - ∑ li (3.5)

= (2.5 X 40.321) – (- 1.3218)

= 102.1243

Ve = V - ∑Vi (3.6)

= (2.5+1) x 40.321 – 4.139

= 136.985

Calculation of the slope for top operating line,

Ve

Le=

984.136

1243.102(3.7)

= 0.7455

Ve’ = V’ - ∑ Vi’ (3.8)

= (2.5+1) x 40.321 – 0.08313

= 141.04

Le’ = L’ - ∑ li’ (3.9)

= (2.5+1) x 40.321 + 66.59 – 3.23

= 204.48

211

Page 212: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Calculation of the slope for bottom operating line,

'

'

Ve

Le =

48.204

04.141(3.10)

= 1.45

Xb = )(

.

HKLKflow

LKflow

+ at bottom, (3.11)

= )47.621(

1

+

= 0.016

Xd = )(

.

HKLKflow

LKflow

+ at top, (3.12)

Xd = )186.33(

86.33

+

= 0.9713

Xf = )(

.

HKLKflow

LKflow

+ at feed, (3.13)

Xf = )44.6386.34(

86.34

+

= 0.3546

For vapor – liquid equilibrium curve, we use the equation of

Y = ( )[ ]xx

11

.

−+ αα

α from LK component (3.14)

= ( )[ ]xx

391.51

391.6

+

Table 3.7 MTBE Equilibrium Curve

x y

212

x391.51

x391.6y

+=

Page 213: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

0 00.1 0.415273980.2 0.615082010.3 0.732574070.4 0.809929870.5 0.864715390.6 0.90555110.7 0.937163260.8 0.962359740.9 0.98291371.0 1.0000

So from the data as above, the McCabe-Thiele diagram was constructed to determine

the number of plates. The top operating line and the bottom operating line were

determined first before the number of plates required could be calculated.

And from the graph plotted, the number of stages needed for the MTBE

distillation column is 11 with the feed point location is at stage number six from bottom.

213

Page 214: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

Bottom Operating Line

Equilibrium Curve

Line for the Number of Stages

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

McCabe-Thiele Diagram

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1

X

Y

Xb = 0.016 Xf = 0.35 Xd = 0.97

At bottom At feed At top

214

Top Operating Line

Page 215: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 3.2 McCabe-Thiele Diagram

From the graph plotted, the number of plate can be determined by calculating the stage

plotting at graph and the number of stages needed is 11 stages. The feeding stage

also can be determined from the graph, feed at stage 6 from bottom.

Calculation for minimum reflux ratio, Rmin,

To get the value of minimum reflux ratio, use the Underwood equation was used,

(J. Douglas, 1988),

Rmin =

−1

1

α

X

X

X

X

H KF

H KD

H KF

L KD

.

.

.

. α (3.15)

=

−1391.6

1

44.63

0.1391.6

44.63

86.33

= 0.0803

Optimum reflux ratio is 0.0803 x 1.5 = 0.1204

Where,

XD.LK = Light key component at top flow

XD.HK = Heavy key component at top flow

XF.LK = Light key component at feed flow

XF.HK = Heavy key component at feed flow

In the calculation, the optimum reflux ratio as 2.5 was used (based on Coulson

& Richardson, Chemical Engineering, Volume 6, and J.M Coulson, J.F Richardson,

Chemical Engineering, Volume Two, Third Edition) as 0.1204 is too low for the

calculation, based on statement from R. K. Sinnot, Coulson & Richardson, Chemical

Engineering, Volume 6, Butterworth Heinemann, 2001, page 495 – “At low reflux

ratios the calculated number of stages will be very dependent on the accuracy of the

vapor-liquid equilibrium data available. If the data are suspect a higher than normal

ratio should be selected to give more confidence in the design”.

215

Page 216: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.3.2 DETERMINATION OF THE NUMBER OF PLATES USING FENSKE’S

EQUATION

The Fenske’s equation (1932) can be used to estimate the minimum stages required at

total reflux. The derivation of the equation is for binary system and applies equally to

multicomponents system. But in the design only the calculation of plates using

McCabe-Thiele method as the design plate number was taken into consideration.

Nmin =

LK

bLK

HK

dHK

LK

x

x

x

x

αlog

log

(3.16)

=

392.6log

000.1

44.62

000.1

86.33log

= 4.13

Nmin ≈ 5 stages

Normally after using the Fenske’s Equation, the value of Nmin is given by the equation

below to get the number of stages, NT,

N T = 2 (Nmin)

= 2 (5)

= 10 stages

To get the real number of stages, the efficiency of the process must be considered,

and the efficiency is calculated based on the equation by O’Connell’s (J. Douglas,

1988),

Eo = ( ) 25.0

5.0

µα (3.17)

= ( ) 25.0392.6x224.0

5.0

= 0.457

216

Page 217: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

N =o

T

E

N

=457.0

11

= 24.07

≈ 24 plates

3.3.3 THE PHYSICAL PROPERTIES

The properties consider in this design are liquid flow rate, LW, vapor flow rate, VW, liquid

surface tension, σ, liquid density, ρl and vapor density, ρv. This physical properties

evaluated at the system temperature by using HYSIS generated data or by manual

calculations the from mass and energy balance data. The useful properties data are

from HYSIS, mass and energy balance data is given as below:

Liquid flow rate, LW = 38747.97 kg/hr (10.7633 kg/s)

Vapor flow rate, VW = 15251.95 kg/hr (4.2367 kg/s)

Liquid surface tension, σ = 0.0351 N/m

Liquid density, ρl = 746.74 kg/m3

Vapor density, ρv = 3.8402 kg/m3

Data evaluated are at system temperatures and pressures.

3.3.4 DETERMINATION OF COLUMN DIAMETER

The principal factor that determines the columns diameter is the vapour flow-rate. The

vapour velocity must be below that which would cause excessive liquid entrainment or

a high-pressure drop. The equation below which is based on the well-known Souders

and Brown equation, Lowenstein (1961), Coulson & Richardson, Chemical

Engineering, Volume 6, page 556, can be used to estimate the maximum allowable

superficial vapour velocity, and hence the column area and diameter,

217

Page 218: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

( ) ( )

−+−=σ

σσ

v

vL047.0lt27.0l2t171.0

2/1

vu (3.18)

= ( ) ( ) ( )

−+−

8402.3

8402.374.7462/1

047.09.027.09.02

171.0

= 0.7997 m/s

Where,

u v= maximum allowable vapour velocity, based on the gross (total)

column cross-sectional area, m/s,

lt= plate spacing, m (range 0.5 – 1.5).

Based on the equation below, the column diameter could be determined,

Dc =

uv

v

w

v

4

π ρ(3.19)

Dc =)7997.0)(8402.3(

)6244.0(4

π

= 0.51 m

Dc = 0.51 x 1.5

= 0.765 m

For safety reason, the approximate diameter was increased 50% more than the

calculated value, as it deals with vapour, which is in high pressure.

218

Page 219: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.3.5 DETERMINATION OF PLATE SPACING

The overall height of the column will depend on the plate spacing. Plate spacings from

0.15 m (6 in.) to 1m (36 in.) are normally used. The spacing chosen will depend on the

column diameter and the operating conditions. Close spacing is used with small-

diameter columns, and where head room is restricted, as it will be when a column is

installed in a building. In the MTBE distillation column, the plate spacing was assumed

0.9 m as it is in the range of 0.5 m to 1 m recommended by Coulson and Richardson,

Chemical Engineering, Volume 6.

3.3.6 LIQUID FLOW ARRANGEMENTS

Before deciding liquid flow arrangement, maximum volumetric liquid rate were

determined by using equation below,

VL = ρL

Lw(3.20)

VL =74.746

97.38747

VL = 51.89 m3/hr

= 0.0144 m3/s

Based on the values of volumetric flow rate and column diameter, Dc. Figure

11.28 from Coulson & Richardson, Chemical Engineering, Volume 6, page 568.

Therefore, types of liquid flow could be considered as single pass.

3.3.7 PLATE LAYOUT

The value of downcomer area, active area, hole area, hole size, and weir height were

determined based on above value calculated, trial plate layout column area determined

by using the equation below,

219

Page 220: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Column area, Ac =)9.0(Uv

Um(3.21)

= )9.0(7997.0

181.4

= 5.81 m2

Where Um = Velocity at below plate,

Down comer area were found by assume 20% of column area and using equation

below,

Down comer Area Ad = 0.2 Ac

= 0.2(5.81 m2)

= 1.162 m2

Net area and active area were determined by using equations below,

Net Area, An = Ac - Ad

= 5.181 -1.162

= 4.02 m2

Active area, Aa = Ac - 2Ad

= 5.181 - 2(1.162)

= 2.857 m2

Hole Area, AH are determine with trial value of 10% active area by equation below,

Hole Area, Ah = 0.10(Aa)

= 0.10(2.857)

= 0.2857 m2

Weir Length, lw was calculated by referring Figure 11.31 from Coulson Richardson,

Chemical Engineering, Volume 6, page 572 which was determined based on the

value of the ratio of Ad/Ac to get the ratio of lw/ Dc .

The weir height determined and other dimensions are as below:

220

Page 221: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Weir Height, hw = 50 mm (standard)

Hole diameter, dh = 5 mm (standard)

Plate Thickness = 5 mm (standard)

Weir Length, Iw = 612 mm (80% x 765)

3.3.8 ENTRAINMENT EVALUATION

The entrainment checking can be done by determine actual flooding percentage, Uv by

using equation below,

Uv =c

m

A

U (3.22)

= 181.5

181.4

= 0.807 m/s

Liquid flow rate were determine by using below equation by using liquid vapor flow

factor.

FLV =5.0

l

v

Vw

Lw

ρρ

(3.23)

=95.15251

97.38747

5.0

74.746

8402.3

= 0.182

Where FLV is liquid vapor factor.

Based on value of FLV and assumption made for initial tray spacing (0.9m) by

referring to Figure 11.27 from Coulson & Richardson, Chemical Engineering, Volume

6, page 567, the data were used to determine the constant, K1 for the estimation of

flooding velocity. Before that, correction factor are used as equation below:

K1 = k1

2.0

02.0

σ

(3.24)

221

Page 222: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 0.1 2.0

02.0

0351.0

= 0.112

And flooding velocity, Uf determine by equation below (correlation given by Fair,

Coulson & Richardson, Chemical Engineering, Volume 6, page 567,

Uf = K1

−v

vl

ρρρ

(3.25)

= 0.112

−v

vl

ρρρ

0.5

= 0.112

5.0

8402.3

8402.374.746

= 1.56 m/s

Actual % of flooding = 100×f

v

U

U(3.26)

= 100560.1

807.0 ×

= 51.8%

Fractional entrainment is calculated based on this percentage and FLV by

referring to Figure 11.29 from Coulson & Richardson, Chemical Engineering, Volume

6, page 570, if unsatisfied, recalculation were done based on chosen diameter and

plate spacing acceptable to determine the lowest value. However, fractional

entrainment Ψ = 0.02, is below the initial guest of 0.1 and entrainment is acceptable.

3.3.9 WEEPING RATE EVALUATION

222

Page 223: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Weir liquid crest were determined by using values of maximum liquid flow rate

and minimum flow rate based on the process condition and also assumption of

turndown percentage based on the liquid characteristic. Each weir liquid crest value

was determined by using equations as follow, the Francis weir formula (see also

Volume 1, Chapter 5),

Max how =3/2

)(

max750

lwl

Lw

ρ(3.27)

= 750 3/2

)88.0)(74.746(

5860.1

= 13.49 mm liquid

Min how =3/2

)(

min750

lwl

Lw

ρ(3.28)

=3/2

)88.0)(74.746(

7633.10750

= 48.37 mm liquid

Where,

Iw = Weir length, 0.88 (standard)

how = weir crest

Lw = liquid flow rate

At minimum liquid flow rate, the value was determined by adding weir height Hw and

weir crest, how the constant, K2 where it is found based on the value by referring to

Figure 11.30 from Coulson & Richardson, Chemical Engineering, Volume 6, page

571.

Minimum vapor velocity Uh, were determined by using the equation as below,

Uh = 5.02 )4.25(90.0

v

dK h

ρ−−

(3.29)

= 5.0)8402.3(

)005.04.25(90.060.28 −−

= 2.931 m/s

(3.3.10, 3.3.11 and 3.3.12: Please refer to the Appendix)

223

Page 224: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.3.13 NUMBER OF HOLES

Area of hole,

AH =4

d 2hπ

(3.30)

=4

)05.0( 2×π

= 1.9634 x 10-3 m2

Number of Holes =H

h

A

A (3.31)

= 3109634.1

2857.0−×

= 145.49

≈ 146 units (at every sieve plate).

3.3.14 COLUMN SIZE

The column height will be calculated based on the equation given below. The equation

determines the height of the column without taking the skirt or any support into

consideration. Its determination is based on condition in the column.

Column Height = (No stage –1) (tray spacing)

+(Tray spacing x 2)

+(No stage-1) (Thickness of Plate)

= (11 -1)(0.9)+(0.9)(2) + (11-1)(0.005)

= 10.85 m

≈ 12.00 m (including 10% safety factor)

The overall height from the calculation is 10.85 m, but in a real construction it

will be added slightly more (about 10%) because of vapor and liquid area at top and

bottom column. The space for vapor and liquid are required if uncertain condition occur

224

Page 225: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

in the column, such as over flooding, over vapor pressure or upset in reaction situation.

The calculated result is tabulated in the Table 5.8 as below.

Table 3.8 Provisional Plate Design Specification

Item ValueColumn Diameter, Dc 0.765 m

No of Plates 11 unitsPlate Spacing 0.9 m

Plate Thickness 5 mm*

Total Column Height, Ht 12.00 mPlate Pressure Drop, ht 192.81 mm liquid*

Plate Material SS 304Down Comer Area, Ad 0.8348 m2

Down Comer Material SS 304Column Area, Ac 5.181 m2

Net Area, An 4.020 m2

Active Area, Aa 2.857 m2

Hole Area, Ah 0.2857 m2

Number of Holes 146 unitsWeir Length 0.612 m

Weir Height (standard) 0.05 m

Resident Time 13.37 seconds*

* For the determination of these values, they are shown in the Appendix section.

3.4 MECHANICAL DESIGN

In the mechanical design, the temperature and pressure are important properties in

evaluating the thickness and the stress of material. Therefore, the safety factor also is

225

Page 226: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

also added as precaution and determined by certain consideration such as corrosion

factor, location and process characteristic.

The safety factor is usually 10% above the operating pressure and as for this

MTBE distillation column, the operating pressure is 450 kPa. The chosen safety factor

is based on the process characteristics of the system. The design temperature is

related to the operating temperature. Based on the calculated result, the temperature

at the top of the column is 53.3oC and the temperature at the bottom of the column is

107oC.

Design Pressure, Pi = 0.450 N/mm2 x 110%

= 0.495 N/mm2

Design Temperature, T = 117.70 ºC (10% more than design temp.)

3.4.1 MATERIAL OF CONSTRUCTION

The material used in the construction of the distillation column is stainless steel

(18Cr/8Ni, 304) as the material is suitable in high temperature and less corrosive. For

this material, the design stress at 150 ºC is obtained from Table 13.2, page 809

Coulson & Richardson, Chemical Engineering, Volume 6.

Design stress, f = 130 N/mm2

Diameter vessel, Di = 860 mm

Tensile strength, = 510 N/mm2

3.4.2 VESSEL THICKNESS

The minimum thickness of column required and other designs are calculated based on

equation below (Coulson & Richardson, Chemical Engineering, Volume 6, page 812):

226

Page 227: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

e = PiJf2

DiPi

− (3.32)

=)495.0()145)(1(2

)765)(495.0(

= 1.31 mm

Based on Table 13.4, Coulson & Richardson, Chemical Engineering, Volume 6,

page 811, this minimum thickness should be added 5 mm to withstand its own weight

and any incidental loads.

e = 1.31 mm + 5 mm

= 6.31 mm

Assumed ≈ 7.00 mm

Where, Pi = Design pressure

Di = Column diameter

f = Design Stress

J = Joint factor (assumed = 1)

From Table 13.4, Coulson and Richardson, Chemical Engineering, Volume 6,

page 811, for diameter 1 m to 2 m the minimum thickness should not be less than 7

mm (including 2 mm of corrosion allowance). For vessel diameter around 0.5 m to 1 m,

a much thicker wall will be needed at the column base to withstand the wind and dead

weight loads.

A much thicker wall is needed at the column base to withstand the wind and

dead weight loads. As a first trial, divide the column into five sections, with the

thickness increasing by 2 mm per section. Try 7, 9, 11, 13 and 15 mm. The average

wall thickness is 11 mm.

3.4.3 HEADS AND CLOSURE

227

Page 228: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Torispherical head had been chosen because of operating pressure below 10 bars and

suitable for liquid vapor phase process in inconsistent high pressure. The calculations

as below is considered,

Crown radius, Rc = Di = 0.765 m

Knuckle radius, Rk = 6% Rc = 0.046 m

Minimum Thickness = )2.0C(PJf2

CRP

si

sci

−+ = 0.2137mm

(The method of calculations is shown in the Appendix section)

3.4.4 TOTAL COLUMN WEIGHT

Total Weight, Tw

Total weight is the summation of the weight of dead weight, the weight of plates and

the weight of insulation. The calculations for the dead weight, the weight of plates and

the weight of the insulation are shown in the Appendix.

Total weight, Wt = Wv + Wp + WI

= (28.46 + 68.53 + 10.63) kN

= 107.62 kN

3.4.5 WIND LOADS

The wind load is calculated based on location and the weather of surrounding.

Therefore, the value of wind speed is assumed as below and wind load is calculated

shown in the appendix. The wind load for the MTBE column is 62.91kN (methods of

calculation in shown in the appendix.

3.4.6 – STIFFNESS RING (Please refer to the Appendix)

Table 3.9 Summarized Results of Mechanical Design

228

Page 229: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Operating pressure, Po 0.45 N/mm2

Design Pressure, Pi 0.495 N/mm2

Safety factor 0.15

Design Temperature, TD 88.78 oC

Operating Temperature, To 80.71 oC

Heads and Closure

Types Torispherical head.

Crown Radius, Rc = Di 0.765 m

Knuckle Radius, Rk = 6% Rc 0.046 m

Joint Factor, J 1.00

Cs 1.77

Minimum thickness head, e 0.2317 mm

Column Weight

Dead weight of vessel, Wv 28.46 kN

Weight of a plate, Wp 6.23 kN

Weight of 11 plates,Wp 68.53 kN

Weight of insulation, WI 10.63 kN

Total weight 107.62 kN

Win speed, Uw 160 km/hr

Wind pressure. Fw 1068.8 N/m2

Bending Moment (Mx) 62.91 kN

Stiffness Ring

Critical buckling pressure for ring, Pc 15 x 106 N/m2

229

Page 230: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3.5 VESSEL SUPPORT DESIGN (SKIRT DESIGN)

Type of Support : Straight cylindrical skirt

θs : 90º

Material of Construction : Carbon steel

Design Stress, fs : 135 N/mm2 at ambient temp. 20ºC

Skirt Height, Hv : 2.5 m (standard)

Young’s Modulus : 200, 000 N/mm2

Approximate Weight : 8.418 kN

Total Weight : 36.88 kN

230

Page 231: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(The method of calculations for other parameters in the vessel support design in shown

in the Appendix section)

Table 3.10 Design Specification of the Support Skirt

Support Data

Type of Support Straight cylindrical skirt

Material of Construction Carbon steel

Design Stress, at T 20ºC (ambient) 135 N/mm2

Skirt Height 2.50 m

Young’s Modulus 200000 N/mm2

σ L 746.74 kg/m3

Approximate Weight, Wapprox 8.418 kN

Total Weight 107.62 kN

Wind Load, Fw 1068.8 N/m2

Skirt Thickness, ts 15 mm

REFERENCES

J. M. Coulson, J. F. Richardson, Chemical Engineering, Volume Two, Third

Edition, The Pergamon Press, 1977.

R. K Sinnot, Coulson & Richardson’s Chemical Engineering, Chemical

Engineering Design, Volume Six, Butterworth Heinemann, 1999.

Robert H. Perry, Don W. green, Perry’s Chemical Engineer’s Handbook,

Seventh Edition, McGraw-Hill, 1998.

James, M. Douglas, Conceptual Design of Chemical Processes, McGraw-Hill

Book Company, 1988.

Martyn S. Ray and David, W. Johnston, Chemical Engineering, Design Project:

A Case Study Approach, Gordon and Breach Science Publishers, 1989.

Carl R. Branan, Rules of Thumb for Chemical Engineers, Gulf Publishing

Company, 1994.

231

Page 232: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Billet, R., Distillation Engineering, Heydon Publishing, 1979.

King, C. J., Separation Processes, Second Edition, McGraw-Hill, 1992.

Kister, H. Z., Distillation Design, McGraw-Hill, 1992.

Lockett, M. J., Distillation Tray Fundamentals, Cambridge University Press,

1986.

Normans, W. S., Absorption, Distillation and Cooling Towers, Longmans, 1961.

Oliver, E. D., Diffusional Separation Procesess, John-Wiley, 1966.

Robinson, C.S., and Gilliland, E.R., Elements of Fractional Distillation, McGraw-

Hill, 1950.

Smith, R., Chemical Process Design, McGraw-Hill, 1995.

Van Winkle, M., Distillation, McGraw-Hill, 1967.

Micheal J. Barber, Handbook of Hose, Pipes, Couplings and Fittings, First

Edition, The Trade & Technical Press Limited, 1985.

Louis Gary Lamit, Piping Systems: Drafting and Design, Prentice-Hall, Inc.,

1981.

David H. F. Liu, Bela. G. Liptak, Wastewater Treatment, Lewis Publishers, 2000.

SECTION 4

DESIGN OF LIQUID-LIQUID EXTRACTION COLUMN

4.1 INTRODUCTION

Liquid-liquid extraction has become an important separation technique in modern

process technology. This is has resulted in the rapid development of a great variety of

232

Page 233: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

extractor types, in the evaluation of which the chemical engineer must primarily depend

on manufacturers’ literature.

To the design, only three components that are considered, - methanol, water

and isobutene- this is because of for most system containing more than four

components, the display of equilibrium data and the computation of stages is very

difficult. In such cases, the requirements are best obtained in the laboratory without

detail study of the equalibria. (Treybal, Mass Transfer Operations, 1987).

Beside that for multicomponent separations also, special computer programs

for these multistage operations embodying heat and material balances and

sophisticated phase equilibrium relations are best left to professionals. Most such work

is done by service organizations that specialize in chemical engineering process

calculations or by specialize in chemical engineering organizations. (Stanley M. Walas,

Chemical Process Equipment, 1988).

Sieve tray (perforated plate) Column were choose for the extraction of these

components. These multistage, countercurrent columns are very effective, both with

respect to liquid-handling capacity and with respect to extraction efficiency, particularly

for system of low interfacial tension, which do not require mechanical agitation for good

dispersion.

4.2 CHEMICAL DESIGN OF LIQUID – LIQUID EXTRACTION COLUMN

4.2.1 Choice of Solvents

There is usually a wide choice of liquids to be used as solvent for extraction operations.

It is unlikely that any particular liquid will exhibit all the properties considered desirable

for extraction, and some compromise is usually necessary. The following factors need

to be considered when selecting a suitable solvent for a given extraction – affinity for

solute, partition ratio, density, miscibility, safety and cost. Based on the factors that

need to be considered water was choosing as a solvent in this system.

4.2.2 Estimation or Gather the Physical Properties

233

Page 234: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Most of the design parameter used were refer to mass balance, energy balance data

and generated by chemical Engineering Simulation Software, HYSIS.

The properties data as state below:

Flowrate at the dispersed phase, QD = 1254.92 ft3/hr

Flowrate at the continuous phase, QC = 1.785 ft3/hr

Density at the dispersed phase, ρD = 24.10 lb/ ft3

Density at the continuous phase ρC = 41.45 lb/ft3.

The data was evaluated at system temperature and pressure.

4.2.3 Determination of Number of Stages

To determine the theoretical stages required, by assuming the minimum solvent to feed

ratio required to remove all the minimum component, so that is the extraction factor, ε =

1(Schweitzer, Separation Handbook). Equation 4.1 was used. The value for Xf =

0.0195 kg CH3OH/ kg water, Ys = 1.57 x 10-6 kg CH3OH/ kg water was compute from

the mass balance at this system.

Number of theoretical stage, Nf = Xf – Ys/m - 1 (4.1) Xr – Ys/m

Nf = 0.0195 – (1.57 x 10 -6 / 0.001) - 1

(1.57 x 10-6 / 0.001)

= 10.42 stages

= 10 stages

Where, Xf = weight solute /weight feed solvent in the feed phase

Ys = weight solute / weight extraction solvent in extract

Xr = weight solute /weight feed solvent in the raffinate phase

m = slope at the equilibrium line dY/dX

234

Page 235: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The number of mass transfer unit, Nor is identical to the number of the theoretical

stages when extraction factor, ε = 1.

Nor = Xf – Ys/m - 1 (4.2)

Xr – Ys/m

Nor = 10 units

By assuming column efficiency, E is 80%, the number of real stages, N was

determining by using equation 4.3.

N = (Nf -1)/ E (4.3)

= (10 – 1)/ 0.8

= 11 stages

4.2.4 Sizing of Sieve Tray

The sieve tray sizing was base on the manufacturer’s literature. Usually the tray

spacing is from (6 to 24) in, and perforation diameter, do usually from (0.32 to 0.64) cm

or (1/8 to 1/4) in diameter. By take 2 ft tray spacing, Zt, 0.25 in holes on 0.75 in

triangular spacing. The downcomer area is found with equation 4.4.

h = 4.5 Vd2 ρC / 2gc (4.4)

∆h = 2 = 4.5 Vd2 ρC / 2gc ∆ρ

2 = 4.5(41.45) Vd2

2(4.18 x 108) 17.35

Vd = 12471 ft/hr

Ad = QD/ Vd (4.5)

= 1254.92 / 12471

= 0.1006 ft2

235

Page 236: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Dd = 4.2948 in (Downcomer diameter)

Where, Vd = Velocity of the dowmcomer

ρC = Density at the continuous phase

gc = gravitational constant

To determine the total holes area in a tray used equation 4.6 and set the velocity

through the holes, Uh are kept below 0.8 ft/sec or 2880ft/ hr to avoid formation of very

small droplet.

Total hole area, AHT = QD/ Uh (4.6)

= (1254.92 / 2880)

= 0.4357 ft2

To find the tray area, by using ratio of the tray area to hole area as state below:

Tray area, AT = 0.866 (ds) 2

Hole area, AH ½ (Л/4) (do) 2

= 2.21( ds/ do) 2

= 2.21 (0.75/0.25)2

= 19.89

Tray Area, AT = 19.89(0.4357)

= 8.666 ft2

Tray Diameter, DT = 3.32 ft

Where, do = perforation diameter

ds = triangular spacing

4.2.5 Number of Holes

Hole area, AH = ½ (Л/4) (do) 2 (4.7)

236

Page 237: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

=½ (Л/4) (0.25) 2

=0.0245 in2

Number of hole, NH = AHT/AH (4.8)

= 0.4357ft2 / 0.0245 in2

= 2560 units

4.2.6 Column Parameter

Number of tray, NT required and the tower high, HT is determining by using equation

4.9 and 4.10 respectively. The efficiency of the tray is base on assumption of the

column efficiency.

Number of trays, NT = Nf / ET (4.9)

= 10 / 0.8

= 13 trays

Column Height, CT = Zt x NT (4.10)

= 2 (13)

= 26 ft + 3 ft (including 1.5 ft at each end)

= 29 ft

Column diameter same with the tray diameter, so

Column diameter, DC = 3.32 ft.

Column area, AC = 8.67 ft2

Net area and active are were determined by using equation 4.11 and 4.12 respectively.

Net area, AN = AC - Ad (4.11)

= 8.67 – 0.1739

= 28.4961ft 2

Active area, Aa = AC - 2Ad (4.12)

= 8.67 – (2 x 0.1739)

= 8.322 ft2

Where, Ad = downcomer area

237

Page 238: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The height equivalent to theoretical stages, (HETS) and height of transfer unit, Hor are

calculated by using equation 4.13 and 4.14 respectively.

HETS = CH / Nf (4.13)

= 29 / 10

= 2.9

Hor = CH / Nor (4.14)

= 2.9

4.2.7 Weeping Evaluation

By analogy with distillation. Weir length, lw is calculated by referring to Figure 11.31

from Coulson and Richardson Vol.6 page 572, which determined the value is base on

the ratio of Ad/AC to get the ratio of lw/DC. The weir height determine from standard form

as follows:

Weir height = 50 mm

Hole diameter = 5 mm

Plate thickness = 5 mm

Weir crest were determined by using value of maximum flowrate and minimum

flowrate based on process condition. Each weir crest value determine by using

equation 4.15 and equation 4.16 respectively.

Max how = 750 Lw max / ρD( lw) 2/3 (4.15)

= 750 3.8106/ (380.048 x 1.2705) 2/3

= 29.73 mm liquid

Min how = 750 Lw min / ρD( lw) 2/3 (4.16)

= 750 0.4512/ (380.048 x 1.2705) 2/3

238

Page 239: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 7.17 mm liquid

At minimum rate hw + how = 50 + 7.17 =57.17 mm

Where, lw = weir length

how = weir crest

Lw = liquid flowrate

Orifice coefficient, Co was referring from figure 11.34 Coulson and Richardson Vol. 6

pg 576 and by assuming.

1. Plate thickness : hole diameter = 1

2. Ah/Ap = 5

Plate pressure drop, h

h = 51 (Uh / Co)2 (ρC/ρD) (4.17)

= 51 (0.2438/0.805)2 (640/380.048)

= 7.88 mm liquid

Residual head, hr

hr = (12.5 x 103) / ρD (4.18)

= 12.5 x 103 / 380.048

= 32.89 mm liquid

Total plate pressure drop, ht

ht = h + (hw + how) + hr (4.19)

= 7.88 + 57.17 + 32.89

= 97.94 mm liquid

Plate pressure drop, ∆Pt

∆Pt = 9.81 x 10-3 ht ρD (4.20)

= 9.81 x 10-3 (97.94) (380.048)

= 365.147 Pa (N/m2)

Table 4.1: Provisional Plate Design Specification

Column Diameter 1011 mm

239

Page 240: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Number of Trays 13 traysTray Spacing 0.6 m

Plate Thickness 5 mmTotal Column Height 9 mPlate Pressure Drop 7.88 mm liquid

Plate Material SS304Downcomer Area 9.3 x 10-3 m2

Column Area 0.805 m2

Net Area 2.647 m2

Active Area 0.773 m2

Hole Area 1.58 x 10-5 m2

Number of Holes 2560 unitsWeir Length 1.2705 m

Weir Height (standard) 50 mmNumber of manhole 2

Manhole Diameter (BS 470:1984) 700 mm

4.3 MECHANICAL DESIGN OF LIQUID – LIQUID EXTRACTION COLUMN

In mechanical design, the temperature and the pressure are important properties in

evaluate the thickness and the stress of material. Therefore, the safety factor also need

as precaution and determined by certain consideration such as corrosion factor,

location and process characteristic.

Based on Hysis data, the operating pressure is 2.75 kPa and the safety factor is

10% above operating pressure. The design temperature related to the operating

temperature. The temperature of column operated in 400C at top of column and 270C at

the bottom of the column. The design pressure and design temperature of the system

as follows:

Design Pressure, Pi = 0.275 N/mm2 x 1.1

= 0.3025 N/mm2

Design Temperature, T = 500C

4.3.1 Material Construction

The material used is stainless steel (18Cr/8Ni, 304). Design stress at 500C is gain from

table 13.2, pg 809 Coulson & Richardson Vol.6.

240

Page 241: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Design stress, f = 165 N/mm2

Diameter Vessel, Di = 1011 mm

Tensile Strength, = 510 N/mm2

4.3.2 Vessel Thickness

The thickness of column is calculated based on the equation below:

e = PiDi (4.21)

2f – Pi

= 0.3025(1011)

2(165) – 0.3025

= 0.9276 mm

Add corrosion allowance 4mm, so the thickness:

e = 4.9276 mm

= 5 mm

From Coulson & Richardson, value for vessel diameter (m), 1 m, the minimum

wall thickness required should not be less than 5mm including corrosion allowance. A

much thicker wall will be needed at the column base to withstand the wind and dead

weight loads. As a first trial, divide the column into five sections (courses) with

thickness increasing by 2mm per section. Try 10,12,14,16, and 18mm. The average is

14 mm.

4.3.3 Design of Domed Ends

Standard torispherical head are the most commonly used end closure for vessel up to

operating pressure of 15 bar. Torispherical head had been choose because of

operating pressure below 10 bar.

Crown Radius, RC = Di = 1.011m

Knuckle Radius, Rk = 6%RC = 0.061 m

241

Page 242: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

A head of this size would be formed by pressing: no joint, so J = one. Stress

concentration factor for torispherical heads, Cs:

Cs = ¼ (3 + √ (RC / Rk)) (4.22)

= ¼ (3 + √ (1.011/0.061))

= 3.053

Therefore the minimum thickness:

e = PiRCCs (4.23)

2fJ + Pi (Cs – 0.2)

= 0.3025(1011) (3.053)

(2 x 165) + (0.3025(3.053 -0.2))

= 2.821 mm

4.3.4 Column Weight

4.3.4.1 Dead Weight of Vessel, Wv

Wv = 240 Cv Dm(Hv + 0.8Dm) t (4.24)

Where;Cv = a factor take 1.15, vessel with plates

Dm = mean diameter, m

= (Di + t)

Hv = height or length between tangent line

t = wall thickness, m

To get a rough estimate of the weight of this vessel by using the average thickness 14

mm.

Dm = 1.011 + 0.014

= 1.025 m

Hence,

Wv = 240(1.15) (1.025) (9 +0.8(1.025)) 14

= 38933.69N

242

Page 243: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 389 kN

4.3.4.2 Weight of plate, Wp

From Nelson (1963) pg 833 in Coulson & Richardson Vol. 6 rough guide to weight of

fittings, take contacting plates, steel including typical liquid loading, 1.2 kN/m2 plate

areas. The total of weight of plate determine by multiply the value with number of tray

design.

Tray area, AT = 0.805 m2

Weight of plate = 1.2 x AT (4.25)

= 1.2(0.805)

= 0.966 kN

Weight of 13 trays, Wp = 0.966(13)

= 12.558 kN

4.3.4.3 Weight of Insulation, Wi

The insulating material is mineral wool;

Density of mineral wool = 130 kg/m3

Thickness of insulation, ti = 75 mm

Volume of insulation, Vi = ЛDiHv x ti (4.26)

= Л (1.0110) (9) (75 x 10-3)

= 2.144m3

Weight of Insulation, Wi = Viρg (4.27)

= 2.144(130) (9.81)

= 2734.11 N

Double this value to allow fittings, so weight of insulation, Wi = 5.468 kN

4.3.4.4 Total weight, W

243

Page 244: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

W = Wv + Wp + Wi (4.28)

= 389 + 12.56 + 5.47

= 407.03 kN

4.3.4.5 Wind Loading

Take dynamic wind pressure, Pw as 1280 N/m2.

Mean diameter, including insulation, Deff:

= 1.011 + 2(0.014 + 0.075)

= 2.791 m

Loading (per linear meter) Fw;

Fw = PwDeff (4.29)

= 1280 (2.791)

= 3572.48 N/m

Bending moment at bottom tangent line. MX

MX = FwX2 (4.30)

2

= 3572.48 (9)2

2

= 144685 Nm

Where; X = Distance measured from the free end

The calculated value as the result tabulated in table 4.2. The value requires

determining in strength and suitability of column while in construction and operation. It

also required the safety consideration operation. The operating procedure of the

column should base on this value.

4.3.5 Analysis of Stress

At bottom tangent line,

244

Page 245: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.3.5.1 Longitudinal and Circumferential Pressure Stress;

σh = PiDi (4.31)

2t

= 0.3025 (1011)

2 (14)

= 10.92 N/mm2

σL = PiDi (4.32)

4t

= 0.3025 (1011)

4 (14)

= 5.46 N/mm2

4.3.5.2 Dead Weight Stress

σL = W (4.33)

Л (Di + t) t

= 407030

Л (1011 + 14) 14

= 9.03 N/mm2

4.3.5.3 Bending Stress

σb = ± MX / IV ((Di/2) + t) (4.34)

Where;MX = Total bending moment

IV = Second bending moment

= Л / 60 (Do4 –Di

4)

Which;

Do = 1011 + 2(14)

= 1039 mm

IV = Л / 60 (10394 –10114)

= 6.32 x 109 mm4

Therefore,

245

Page 246: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σb = ± 144685000 ((1011 / 2) + 14)

6.32 x 109

= ± 11.89N/mm2

The result longitudinal stress, σZ is:

σZ = σL + σW ± σb

σZ (upwind) = σL - σW + σb

= 5.46 – 11.15 + 11.89

= 6.2 N/mm2

σZ(downwind) = σL - σW - σb

= 5.46 – 11.15 – 11.89

= -17.58 N/mm2

4.3.5.4 Elastic Stability (Buckling)

Critical buckling stress, σC:

σC = 2 x 104 (t / Do) (4.35)

= 2 x 104 (14 / 1039)

= 269.48 N/mm2

The maximum compressive stress will occurs when the vessel is not under pressure:

σW + σb = 11.15 + 11.89

= 23.04N/mm2

This value is below critical buckling stress, so design is satisfactory.

Stresses analysis is tabulate in the table 4.3.

4.3.6 Vessel Supports Design

4.3.6.1 Skirt Supports

At ambient temperature.

246

Page 247: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Type of support : Straight cylindrical skirt (θS = 900)

Material construction : Plain carbon steel

Design stress : 135 N/mm2

Young’s Modulus : 200000 N/mm2

Skirt height, Hs : 3 m

The maximum dead weight load on the skirt will occur when the vessel is full of the

mixture.

Approximate weight, Wapprox = (Л / 4) Di2 HVρLg (4.36)

= (Л / 4) (1.0112) (9) (380.048) (9.81)

= 26936.56 N

= 26.9 kN

Total weight = W + Wapprox

= 407.03 + 26.9

= 433.93kN

Bending moment at base of skirt, MS:

MS = Fw (HV + HS)2 (4.37)

2

= 3.572 (122 / 2)

= 257.184 kNm

As a first trial, take the skirt thickness as the same as that of the bottom section of the

vessel, ts = 14 mm.

Bending stresses in skirt, σbs = 4Ms / (Л (Ds + ts) tsDs) (4.38)

Where; Ms = Maximum bending moment at the base of the skirt.

ts = Skirt thickness

Ds = Inside diameter of the skirt at the base

So,

247

Page 248: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σbs = 4 (257184 x 103) / Л (1011+14) (14) (1011)

= 22.5710 N/mm2

Dead weight stress in the skirt, σWs:

σWs(test) = W / (Л (Ds + ts) ts) (4.39)

= 26900 / Л (1011+14) (14)

= 0.60 N/mm2

σWs(operating) = 407030 / Л (1011+14) (14)

= 9.03 N/mm2

Thus, the resulting stress in the skirt, σs:

Max σs (compressive) = σWs(test) + σbs (4.40)

= 0.60 + 22.57

= 23.17 N/mm2

Max σs (tensile) = σbs - σWs(operating) (4.41)

= 22.57 – 9.03

= 13.54 N/mm2

Take the joint factor, J as 0.85.

Criteria for design

σs (tensile) >fs J sin θ

13.54 > 0.85 (135 sin 900)

13.54 > 114.75

248

Page 249: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

σs (compressive) > 0.125 E (ts/DS) sin θ

23.17 > 0.125 (200000) (14/1011) sin 900

23.17 > 346.19

Both criteria are satisfied; add 2mm for corrosion gives a design thickness of 16 mm.

4.3.6.2 Base Ring and Anchor Bolt

Approximate pitch circle diameter, say 2.2 m.

Circumferences of bolt circle = 2200 Л

Л of bolt required, at minimum recommended bolt spacing:

= 2200 Л / 600

= 11.5

Closet multiple of 4 = 12 bolts

Take bolt design stress = 125 N/mm2

Bending moment at skirt, MS = 301.834 kNm

Total weight vessel, W = 502.53 kN

Area of bolt, Ab = 1 4MS - W (4.42)

Nbfb Db

Where:Nb = Number of bolts

fb = Maximum allowable bolt stress

MS = Bending moment at the base

W = Weight of the vessel

249

Page 250: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Db = Bolt Circle diameter

Therefore,

Ab = 1 4 (257184) - 407030

12 (125) 2.2

= 40.35 mm2

Bolt root diameter = √ (40.38 x 4) / Л

= 7.17 mm

Total compressive load on the base ring per unit length.

Fb = 4MS + W (4.43)

Л DS2 Л DS

= 4 (257184) + 407030

Л (1.0112) Л (1.011)

= 448.5 x 103 N/m

By taking the bearing pressure as 5 N/mm2. The minimum width of the base ring, Lb:

Lb = Fb + 1 (4.44)Fc 103

= 448.5 x 103

5000

= 89.7 mm

Actual width can be calculated from this minimum width.

Use M24 bolts (BS 4190:1967) root area = 353 mm2 (Figure 13.30 Coulson &

Richardson Vol. 6)

250

Page 251: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Actual width required = Lr + ts + 50mm

= 150 + 14 + 50

= 214 mm

Actual bearing pressure on concrete foundation:

f’c = Fb

actual width

= 448500

214000

= 2.10 N/mm2

Actual minimum base thickness:

tb = Lr √ (3 f’c / fr) (4.45)

= 150 √ ((3 x 2.1) / 140)

= 25.98 mm

Where: fr = Allowable design stress in the ring material, typically 140 N/mm2

The design specifications of support are summarized in the table 4.4.

4.3.7 Piping Sizing

The optimum diameter for carbon steel pipe:

d, optimum = 293 G 0.53 ρ-0.37 (4.46)

Where:G = Flowrate (kg/s)

ρ = Density (kg/m3)

Pipe thickness, t = P d, optimum (4.47)

251

Page 252: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

20σ + P

Where:P = Internal pressure, bar

σ = Design stress at working temperature, N/mm2

The piping sizing for this system are shown in table 4.5

Table 4.2 : Summary of the Mechanical Design

Design Pressure

Operating Pressure 2.75 kPa

Operating Temperature 40 0C

Design Pressure 0.3025 N/mm2

Design Temperature 50 0C

Safety Factor 0.10

Design of Domed Ends

Types Torispherical head

Crown Radius 1.011 mKnuckle Radius 0.061 mJoint Factor 1Stress Concentration Factor 3.053Minimum Thickness 2.821 mmColumn WeightDead Weight of Vessel 389 kNWeight of Plate (per plate) 0.966 kNWeight of Insulation 2734.11 NTotal Weight 407.03 kNWind Pressure 1280 N/m2

Loading 3572.48 N/mBending Moment 144.685 kNm

252

Page 253: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.3: Stress Analysis for Liquid-Liquid Extraction Column

Longitudinal Pressure Stress 10.92 N/mm2

Circumferential Pressure Stress 5.46 N/mm2

Dead Weight Stress 9.03 N/mm2

Bending Stress ± 11.89 N/mm2

σZ (upwind) 6.2 N/mm2

σZ(downwind) -17.58 N/mm2

Critical Buckling Stress 269.48 N/mm2

Table 4.4: Design Specification of the Support Skirt

Types of Support Straight cylindrical skirtθ 90 0CMaterial Construction Plain Carbon steelDesign Stress 135 N/mm2

Skirt Height 3 mYoung Modulus 200000 N/mm2

ρL 380.048 kNApproximate Weight 26.9 kNTotal weight 433.93 kNBending Moment at Skirt 257.184 kNmSkirt Thickness 14 mBending Stress in Skirt 22.57 N/mm2

σ ws (test) 0.60 N/mm2

σ ws (operating) 9.03 N/mm2

Maximum σs (compressive) 23.17 N/mm2

Maximum σs (tensile) 13.54 N/mm2

253

Page 254: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.5: Piping Sizing for Liquid-liquid Extraction Column

Feed Pipe SizingFlowrate, G 13873.67 kg/hrDensity, ρ 567.0445 kg/hrInternal Pressure, P 2.75 barDesign Stress, σ 165 N/mm2

Diameter Optimum, d optimum 55 mmCorrosion Allowance 4 mmPipe Thickness, t 4.05 mmSolvent Pipe SizingFlowrate, G 1469.1 kg/hrDensity, ρ 998 kg/hrDiameter Optimum, d optimum 15 mmExtract Pipe SizingFlowrate, G 1624.37 kg/hrDensity, ρ 992.8161 kg/hrDiameter Optimum, d optimum 15 mmRaffinate Pipe SizingFlowrate, G 15096.74 kg/hrDensity, ρ 564.7173 kg/hrDiameter Optimum, d optimum 30 mm

4.4 PROCESS CONTROL AND INSTRUMENTATION OF THE LIQUID-LIQUID

EXTRACTION COLUMN

Control systems are very important in any of the chemical industries. It is essential for

a process to meet the design specification and products purity that imposed by the

designer or by external constrains such as government regulations and standards.

254

Page 255: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Process parameters control is to compensate for the process changes with the

existence of external disturbances. Normally, an overall control strategy is design to

meet the following objectives:

1. Ensure stable plant operation conductive to power optimization

2. Maintain product quality according to specification

3. Operate the process and machinery in such a way as to estimate or minimize

the possibility of activating last resort safety measures such as relief valve and

surge system, thus ensuring safe plant operation.

Compensate for perturbations cause by external factors such as ambient and

cooling water temperature variations. Provide an intelligent man-machine interface

capable of presenting process and control system information and interactive format.

Typically, there are two types of control systems- feedback control and feed

forward control. In this case, the feedforward control is applied; in feedforward control

its take corrective action before they upset the process. In this system also, solvent use

is lighter than the material being extract, the two input indicated are of course

interchanged. Both inputs are on flow control. The light phase is removing from the

tower on LC (level control) or at the top of level maintain with an internal weir. The

bottom stream is removed on interfacial level control (ILC). The relative elevations of

feed and solvent input nozzles depend on the nature of the extraction process. The

temperature of an extraction process ordinarily is controlled by regulating the

temperature of the feed stream.

REFERENCES

Buford D.Smith, 1963. Design of Equilibrium Stage Processes, United State of

America. McGraw-Hill.

Robert C.Reid,Prausnitz & Poling,1987.The properties of Gases and Liquid, United

State of America. McGraw-Hill.

255

Page 256: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Erneat J.Henley & J.D Seader, 1968.Equilibrium-Stages Separation Operations in

Chemical Engineering. Canada. John Wiley & Sons

Philip A.Schweitzer,1988. Handbook of Separations Techniques for Chemical

Engineers,2nd Edition. United State of America. McGraw-Hill.

J.D Seader & Erneat J.Henley, 1998.Separation Process Principles, United State of

America. John Wiley & Sons

R.K.Sinnott, 1999.Chemical Engineering Design, Coulson & Richardson Chemical

Engineering .3rd Edition. Volume 6 .Britain. Butterworth Heinemann

Robert H. Perry, Don W. Green, 1998 Perry’s Chemical Engineer’s Handbook, Seventh

Edition, McGraw-Hill.

J.R Backhurst & J.H Harker.1987.Chemical Engineering Design, Coulson &

Richardson Chemical Engineering .3rd Edition. Volume 2 .United Kingdom.

Pergamon Press.

Stanley M. Walas. 1988. Chemical Process Equipment Selection and Design. United

State of America. Butterworth’s Series in Chemical Engineering.

Robert E.Treybal.1988. Mass-Transfer Operations,3rd Edition. Singapore, McGraw-Hill

International Series.

K.H Reissinger & Jurgen Schroter. 1980. Selections Criteria for Liquid-liquid

Extractors. Chemical Engineering Magazine, November: 274-256.

P.J Bailes,C.Hanson & M.A Hughes.1976. .Liquid-liquid Extraction: The process, the

equipment. Chemical Engineering Magazine, January 217-231.

Ariffin Marzuki & Nurul Izzi, 2004. PETRONAS Research Centre, Bangi. Interview,19

January.

SECTION 5

256

Page 257: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

DESIGN OF HEAT EXCHANGER

INTRODUCTION

Shell and tube heat exchangers are the most versatile type of heat exchangers. They

are used in process industries, in conventional and nuclear power stations as

condensers, in steam generators in pressurized water reactor power plants, in feed

water heaters and in some air conditioning and refrigeration systems. They are also

proposed for many alternative energy applications including ocean, thermal and

geothermal. Shell and tube heat exchangers provide relatively large ratios of heat

transfer area to volume and weight and they can be easily cleaned.

Shell and tube heat exchangers offer great flexibility to meet almost any service

requirement. The reliable design methods and shop facilities are available for their

successful design and construction. Shell and tube heat exchangers can be designed

for high pressures relative to the environment and high pressure differences between

the fluid streams.

Shell and tube heat exchangers are built of round tubes mounted in a cylindrical

shell with the tubes parallel to the shell. One fluid flows inside the tubes, while the other

fluid flows across and along the axis of the exchanger. The major components of this

exchanger are tubes (tube bundle), shell, front-end head, baffles and tube sheets.

Shell types-various front and rear head types and shell types have been standardized

by Tubular Exchanger manufacturers Association (TEMA).

The E-shell is the most common due to its cheapness and simplicity. In this

shell, the shell fluid enters at one end of the shell and leaves at the other end that is

there is one pass on the shell side. The tubes may have a single or multiple passes

and are supported by transverse baffles. This shell is the most common for single-

phase shell fluid applications. With a single-tube pass, a nominal counter flow can be

obtained. The design of a shell and tube heat exchanger is an iterative process

because heat transfer coefficients and pressure drop depend on many geometric

factors, including shell and tube diameters, tube length, tube layout, baffle type and

257

Page 258: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

spacing and the numbers of tube and shell passes, all of which are initially unknown

and are determined as part of the design process.

In production of MTBE, heat exchanger is very important equipment. Heat

exchanger is used to increase or to decrease the mixture to the desired temperature. In

order to make the process of production of MTBE taking place in the system, it is

important to make the system at the correct environment. The heat exchanger that we

used here is the shell and tube exchanger. Shell and tube heat exchanger is the most

common type of heat exchanger used in the industry. This is because it has many

advantages. The advantages are: -

1. It provided a large transfer area in a small space.

2. Good mechanical layout: a good shape for pressure operation.

3. Used well-established fabrication techniques.

4. It can be constructed from a wide range of materials.

5. It can be clean easily.

6. Well-established design procedures.

7. Single phases, condensation or boiling can be accommodated in either

the tubes or the shell, in vertical or horizontal positions.

8. Pressure range and pressure drop are virtually unlimited and can be

adjusted independently for the two fluids.

9. Thermal stresses can be accommodated inexpensively.

10. A great variety of materials of construction can be used and may be

different for the shell and tubes.

DESIGNING THE HEATER

In the production of MTBE, a heater is the most important heat exchanger in the

system. Therefore this chapter is going to describes details for this heater and the

design of this piece of equipment.

258

Page 259: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Heater is used in the process to heated the raw material of MTBE consist of

isobutane and a bit of normal butane. Isobutane and normal butane from the storage is

in liquid form. The heating process is because to produce the isobutane and normal

butane in the gases form before this material is feed to the Snamprogetti Fluidized Bed

Reactor. Here the mixtures of this component initially are in the liquefied gas form at

temperature of -15 oC. It will be heated in the Heater (E-100) and Heater (E101) until it

converted into gas form at temperature of 250 oC using steam. For this heat exchanger

we use the counter current process. The temperature difference between liquid and

gas phase is quit big, so we need two heat exchanger in series. The shell and tube

heat exchanger is the floating head type.

E100 E101

STREAM 3

STEAM OUT STEAM OUT

STREAM 4

STEAM IN STEAM IN

STREAM 2T = -15OC

T = 250OC

T = 120 OC

T = 350OC

T = 250OC

T = 117 OCT = 250OC

Figure 5.1 : Heat Exchanger In Series For The Heating Process

5.1 CHEMICAL DESIGN OF HEAT EXCHANGER

The chemical engineering design for the heat exchanger is also known as thermal. The

design requires the calculation of the heat transfer area required. From this value,

design features of the unit such as the tube and shell size, tube counts and layout is

determined. In addition, then pressure loss of the fluids across the unit is also

calculated by determined the pumping capacity required. The calculation of the design

259

Page 260: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

is base on the first heat exchanger (E100). The chemical design is based on Bell’s and

Kern method. Bell’s method accounts for the major bypass and leakage streams. Kern

method was based on experimental work on commercial exchangers with standard

tolerances and will give a reasonably satisfactory prediction of heat-transfer coefficient

for standard design.

5.1.1 Physical Properties Of The Stream

Table 5.1: Properties of Raw material (Isobutane and N-butane) and

Steam for (E100)

Component Raw material (Isobutane

and normal butane)

Steam

Temperature inlet, oC t1 = -15 T1 = 250Temperature outlet, oC t2 = 117 T2 = 120Specific heat, j/kg oC 2155 2010

Thermal conductivity, W/mK 0.07 0.0306575Density, kg/m3 485 0.49375Viscosity, kg/ms 1.30005 x 10-4 1.55263 x 10-5

Feed flowrate, kg/s 10.9314 1.7649

5.1.2 The Calculation Of ∆ Tm

To determine the mean temperature, Tm

(5.1) TF =T lmtm ∆∆

Where

∆ Tm = true temperature difference

260

Page 261: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Ft = temperature correction factor

Before ∆ Tm can be obtained, logarithmic mean temperature ∆ Tlm must be calculated

Using the equation:

(5.2)

)t-(T

)t-(Tln

)t-(T-)t-(T =T

12

21

1221lm∆

Where

∆ Tlm = log mean temperature difference

T1 = inlet shell-side fluid temperature

T2 = outlet shell-side fluid temperature

t1 = inlet tube-side temperature

t2 = outlet tube-side temperature

C 134.00 = T

(-15))-(120

117)-(250ln

)15+(-)117-(=T

0lm

lm

∆120250

the temperature correction factor can be obtain by using figure 12.19 (Coulson &

Richardson’s Chemical Engineering)

261

Page 262: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

0.50 = S

(-15))-(250

(-15))-(117 = S

(5.4) t-T

t-t = S

0.98 = R

(-15))-(117

120)-(250 = R

(5.3) t-t

T-T = R

11

12

12

21

Using figure 12.19, (Coulson & Richardson’s Chemical Engineering)

Ft = 0.82

Substitute the above value into equation (1.1) below :

C109.88 = T

)C .)(.(=T

TF=T

0m

0m

lmtm

∆∆

00134820

From table 12.1 (Coulson & Richardson’s Chemical Engineering), we take overall

Coefficient, U = 300 W/m2 0 C

Duty for this heat exchanger is obtain from the energy balance. The duty is,

Q = 3109542.883 W

262

Page 263: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Then we need to calculate the surface area using equation below.

2

m

m 94.33 =A

).)((

33109542.88=A

(5.5) TU

Q= A

88109300

5.1.3 Number Of Tubes Calculation

From table 12.3 (Coulson & Richardson’s Chemical Engineering), we take standard

pipe of:

Inside diameter, di = 16 mm

Outside diameter, do = 20 mm

Length of pipe is assumed as 16 ft.

Length, L = 4.88 m

Area of the pipe can be calculated using equation below

area = Lπ D (5.6)

area = (4.88)(3.142)(0.02)

area = 0.3067 m2

Using the area needed from the duty and area for each tube, the number of

Tube, Nt that we get is,

307.56 = N

0.3067

94.33 = N

(5.7) a

A = N

t

t

t

Therefore the number of tube, Nt = 308 tubes

263

Page 264: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.1.4 Bundle And Shell Diameter Calculation

The tubes in heat exchanger are usually arranged in an equilateral triangular, square

or rotated pattern. The triangular and rotated square patterns give higher heat transfer

rates. Here we use the triangular pattern.

The triangular pitch of 1.25 is chosen as the tube arrangement.

Bundle diameter

(5.8) )K/N(d =D /1tob

11 n

From table 12.4 (Coulson & Richardson’s Chemical Engineering), for 1.25 triangular

pitch, number of passes = 2, then we can obtain

K1 = 0.249

n1 = 2.207

0.50m = D

).0/(0.02 =D

)K/N(d =D

b

./b

/1tob

20721

1

249308

1n

Assume using pull-through floating head type.

From figure 12.10 (Coulson & Richardson’s Chemical Engineering), for bundle

diameter 0.33, bundle clearance is 93 mm.

Shell diameter, Ds

Ds = 0.50 + 0.093

= 0.60m

5.1.5 Tube Side Coefficient, hi

264

Page 265: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Mean temperature of the tube

C 51 = t

2

117 +15- = t

(5.9) 2

t +t = t

omean

mean

21mean

cross sectional area = π d12/ 4 (5.10)

= (3.142)(0.0162) / 4

= 0.0002 m2

Tube / pass = 308 / 2 (5.11)

= 154 tube / pass

Total flow rate area = (cross sectional area)(tube / pass) (5.12)

= (0.0002)(154)

= 0.0308 m2

Steam mass velocity, Gt = (steam flow rate)/(total flow rate area) (5.13)

= (1.7649)/(0.0308)

= 57.30 kg / sm2

Steam linear velocity, u1 = (Gt)/(steam density) (5.14)

= (57.30)/(0.49375)

= 116.05 kg / ms

Ratio of L / di = 4.88 / 0.016 (5.15)

= 305

Reynolds number, Re

265

Page 266: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

59047.87 = Re

10x .

(0.016) ).( 0.49375)(= Re

(5.16) d

= Re

5-

i

552631

05116

µνρ

Heat transfer factor figure 12.31 (Coulson & Richardson’s Chemical Engineering),

Jh = 4.1 x 10-3

Prandtl number,

1.0180 = Pr

0.0306575

)10 x .)(10 x (2.010 = Pr

(5.17) k

C = Pr

5-3

f

p

552631

µ

Tube side coefficient, hi can be calculated using equation below.

C m / W466.62 = h

0.016

7)(1.0180)5)(59047.8)(0.03065710 x (4.1 = h

(5.18) d

PrRekj = h

oi

0.333-

i

i

.fh

i

330

266

Page 267: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.1.6 Shell Side Coefficient, hs

Take baffle spacing as 1/3 from the shell diameter, so Baffle spacing:

lB = Ds / 3 (5.19)

= 0.60 / 3

= 0.20 m

Tube pitch, pt = 1.25 do (5.20)

= (1.25)(0.02)

= 0.025 m

Flow area, As

2s

s

t

Bsots

m 0.0240 = A

0.025

)(0.20)0.02)(0.60-(0.025 = A

(5.21) P

))(I)(Dd-(P = A

Mass velocity, Gs

s m / kg 455.48 = G

0.0240

10.9314 = G

(5.22) A

W = G

2s

s

s

ss

Shell side velocity

267

Page 268: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

s / m 0.9391 = u

485

455.48 = u

(5.23) ρ

G = u

s

s

ss

Shell side equivalent diameter for triangular pitch arrangement

m 0.0142 = d

))0.917(0.02-.0(0.02

1.10 = d

(5.24) )0.917d-p(d

1.10 = d

e

e

o2t

oe

22

2

025

Calculate the Reynolds number

49750.52 = Re

50.00013000

.0142)(455.48)(0 = Re

(5.25) μ

dG = Re

Isobutane

es

Prandtl number

4.0023 = Pr

0.07

00130005)(2155)(0.0 = Pr

(5.26) k

μ C = Pr

f

IsobutanepIsobutane

268

Page 269: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Choose baffle cut of 25%, from figure 12.30 (Coulson & Richardson’s Chemical

Engineering), we can obtained

Jf = 2.70 x 10-2

Assumed that the viscosity correction is negligible

C m / W10513.35 = h

0.0142

))(4.0023)(49750.5210 x 0(0.07)(2.7 = h

(5.27) d

PrRejk = h

o2s

1/32-

s

e

/ff

s

31

5.1.7 Overall Heat Transfer Coefficient, Uo

Material of construction = carbon Steel

Thermal conductivity of the tube wall

Kw = 38 W/moC

Assumed dirt coefficient as

hid = 8500 W/m2 oC

hod = 8500 W/m2 oC

( )

C m / W322.85 = U

/ WC m 0.0039738 = U

1

(5.28) )/d(dh

1+/dd

h

1 +

2k

)/dln(dd+

h

1+

h

1=

U

1

o2o

o2

o

ioi

ioidw

ioo

odso

5.1.8 Tube Side Pressure Drop

269

Page 270: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Reynolds number , Re = 59047.87

From figure 12.24 (Coulson & Richardson’s Chemical Engineering),

jf = 3.10 x 10-3

Neglect the viscosity correction term

[ ]

[ ]

kPa 66.92 =P

m / N 66921.86 =P

).)( . (2.5+16))(4.88/0.010 x 8(3.102 =P

(5.29) μρ

2.5 + )μ/μ)(L/d(j N =P

t

2t

3-t

iim-Wifpt

2

05116493750

28

2

2

5.1.9 Shell Side Pressure Drop

Reynolds number

Re = 49750.52

From figure 12.30 (Coulson & Richardson’s Chemical Engineering),

Jf = 2.70 x 10-2

Shell side pressure drop can be calculated using equation below

( ) ( ) ( ) ( )kPa 47.63 = P

(5.30) μ/μ/ρμL/Id/D8j = P -0.14wsBedf

∆∆ 2

Table 5.2: Summary Of Chemical Design For Heat Exchanger In Series

270

Page 271: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Heat Exchanger E100Temperature range, (o C) Shell side 250 →150

Tube side -15 → 117Feed flow rate, (kg/hr) 39353Steam flow rate, (kg/hr) 6353.64Log mean temperature

difference, ,∆ Tm (o C)

134.00

True temperature

difference, ∆ Tm (o C)

109.88

Overall coefficient, U (W/m2

o C)

300

Duty, Q (w) 3109542.883Surface are, A (m2) 94.33Length of tube or shell, L 4.88m or 16 ftTube diameter di (mm) 16Tube diameter do (mm) 20Area of pipe, a (m2) 0.3067Number of tube, Nt 308Bundle diameter, Db(m) 0.50Shell diameter, Ds(m) 0.60Baffles spacing, IB(m) 0.2000Tube side coefficient, hi

(W/m2 o C)

466.62

Shell side coefficient,

hs(W/m2 o C)

10513.35

Overall heat transfer

coefficent, Uo (W/m2 o C)

322.85

Tube side pressure drop,

∆ P (kPa)

66.92

Shell side pressure drop,

∆ P (kPa)

47.63

5.2 MECHANICAL DESIGN OF HEAT EXCHANGER

The mechanical engineering design of heat exchanger determines the physical

elements that make up the unit as well as their respective dimensions. This design

follows the procedures specified by the Tubular Heat Exchanger association (TEMA)

Mechanical Standards. It is applicable to shell and tube exchangers with internal

diameter not exceeding 60 in. (1524mm), a maximum design pressure of 3000psi (204

bar) or a maximum product of nominal diameter (in) and design pressure (psi) of

271

Page 272: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

60000. In addition, the design also complies with the American Society of mechanical

Engineers (ASME) Boiler and Pressure Vessel Code, Section VIII, Division 1.

5.2.1 Design Pressure

For the design of tube and shell parts, a safety factor of 10% is included to determine

the design pressures.

Operating pressure = 1.1 bar

10% above the pressure for safety

Pi = 1.1 x 10

= 11 bar

= 1.1 N / mm2

5.2.2 Design Temperature

For the shell side and tube side the operating temperature is at 250 oC, so:

Shell-side design temperature = 1.1x 250 oC

= 275 oC

Adding 2 oC for uncertainties in temperature prediction

TD = 275 + 2

= 277 oC

5.2.3 Material Of Construction

For the heat exchanger, the material used for construction is carbon steel. This

selection of material is depending on the economic factor and also level of

corrosiveness of the fluid used. Since the properties of the fluid both in the tube and

also in the shell are not corrosive fluid, therefore the carbon steel is used because it is

more economics compared to stainless steel.

5.2.4 Exchanger Type

For the heater design, pull through floating head exchanger is chosen as the

exchanger type. Internal floating head is versatile than other type and also suitable for

272

Page 273: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

high temperature different between shell and tubes. The tube for internal floating head

also can be rod from end to ends and the bundle are easier to clean.

5.2.5 Minimum Thickness Of Cylindrical Section Of The Shell

The minimum thickness of the cylindrical section of the shell to stand the pressure can

be obtained from the calculation below.

(5.30) P-2j

DP = e

if

ii

Where,

Pi = design pressure

Di = shell diameter

F = design stress (from table 13.2, Coulson & Richardson’s Chemical Engineering)

adding the corrosion allowance = 2 mm

e = 3.91 + 2

e = 5.91 mm

Take the round number of the thickness

e = 6.00 mm

5.2.6 Longitudinal Stress

mm / 55.00 =

2(6)

(1.1)(600) =

(5.31) 2t

DP =

2h

h

iih

σ

σ

σ

273

mm 3.91 = e

(1.1)-2(1)(85)

(1.1)(600) = e

Page 274: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

5.2.7 Circumferential Stress

2h

h

iih

mm / N 27.50 =

4(6) / (1.1)(600) =

(5.32) 4t

DP =

σ

σ

σ

5.2.8 Minimum Thickness Of Tube Wall

Minimum thickness of the tube wall can be calculated using the equation (5.30):

i

ii

P-2jf

DP = e

mm 3.91 = e

(1.1)-2(1)(85)

(1.1)(600) = e

adding the corrosion allowance = 2 mm

e = 3.91 + 2

e = 5.91 mm

5.2.9 Minimum Thickness Of Head And Closure

The minimum thickness of the torispherical head can be calculated by ,

(5.33) )0.2-C(P + 2jf

CRP= e

si

sci

Rc = crown radius

Rk = knuckle radius

Cs = stress concentration factor for torispherical head

274

Page 275: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

[ ] (5.34) R/R + 31/4 = C kcs

Rc = Ds = 600 mm

Rk = 0.06(500) = 36 mm

Cs = 1.77

mm 6.80 = e

0.2)-1.1(1.77+2(1)(85)

(1.77)(1.1)(600) = e

Adding corrosion allowance

e = 6.80 + 2

= 8.80 mm

5.2.10 Minimum Thickness Of The Channel Cover

(5.35) /f))(P)(D(C = e 1/2iep

where

Cp = a design constant, depend on the edge constraint (0.45)

De = nominal plate diameter

f = design stress

e = (0.45)(600)(1.1/85)1/2

= 30.72 mm

Adding corrosion allowance = 2 mm

E = 30.72 + 2

= 32.72 ≈ 33 mm

5.2.11 Design Load

Dead weight of vessel

275

Page 276: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(5.36) 10 x )t0.8D+g(HDπρC = W -3mvmmvv

where

Wv = total weight of the shell

Cv = 1.08 for vessels with only few internal fitting

Wv = (1.08)π (7700)(0.602)(9.81)(4.88+0.8(0.602))(2 x 10-3)

= 1654.45 N

Weight of tubes

N 51362.08 = W

00)(9.81))(4.88)(770.016-π(0.02= W

(5.37) gLρ)d-d(πN = W

t

2 2t

m21

2ott

308

Weight of insulation

Material used = mineral wool insulation

Insulation thickness = 50 mm = 0.05 m

Density = 130 kg / m3

Approximate volume of insulation

[ ][ ]

N 3366.79 = W

)(9.81)(2.64)(130 = W

(5.39) g Vρ= W

m 2.64 =V

(0.50) - 0.05) + (0.60 (4.88) π =V

(5.38) r-)r + r(πH =V

t

t

t

3

22

31v

2

Total weight of heat exchanger

WT = Wv + Wt + Wi (5.40)

276

Page 277: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

WT = 1654.45 + 51362.08 + 3366.79

= 56383.32 N

= 56.38 kN

5.2.12 Pipe Size Selection For The Nozzle

pipe size for isobutane inlet

material of construction = carbon steel

density inlet isobutane, ρ = 600 kg / m3

flow rate isobutane at inlet, Gisobutane = 10.9314 kg / s

Diameter pipe for isobutane inlet, Disobutane

Disobutane (in) = 293G0.53ρ -0.37 (5.41)

Disobutane (in) = 293(10.9314) 0.53(600)-0.37

Disobutane (in) = 97.60 mm

Pipe size for isobutane at outlet,

material of construction = carbon steel

density outlet isobutane, ρ = 370 kg / m3

flow rate isobutane at outlet, Gisobutane = 10.9314 kg / s

Diameter pipe for isobutane outlet, Disobutane

Disobutane (out) = 293G0.53ρ -0.37

Disobutane (out) = 293(10.9314) 0.53(370)-0.37

Disobutane (out) = 116.72 mm

Diameter pipe for steam at inlet stream

277

Page 278: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

material of construction = carbon steel

density inlet steam, ρ = 0.5654 kg / m3

flow rate steam at inlet, Gsteam = 1.7649 kg / s

Diameter of pipe

Dsteam (in) = 293G0.53ρ -0.37

Dsteam (in) = 293(1.7649) 0.53(0.5654)-0.37

Dsteam (in) = 488.94 mm

Diameter pipe for steam at outlet stream

material of construction = carbon steel

density outlet steam, ρ = 0.4221 kg / m3

flow rate steam at outlet, Gsteam = 1.7649 kg / s

Diameter of pipe

Dsteam (out) = 293G0.53ρ -0.37

Dsteam (out) = 293(1.7649) 0.53(0.4221)-0.37

Dsteam (out) = 544.79 mm

278

Page 279: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 5.2 : Steel pipe nozzle

Table 5.3 : by taking D = 100 mm, the selected tube nozzle is :

Nominal pipe size, inch

Outside diameter, inch

Schedule no. Wall thickness, inch

Inside diameter, inch

4 4.5 (114.30) 4OST 0.237 (6.02 mm)

4.026(102.26 mm)

Table 5.4 : by taking D = 500 mm, the selected tube nozzle is :

Nominal pipe size, inch

Outside diameter, inch

Schedule no. Wall thickness, inch

Inside diameter, inch

20 20 (508) 4OST 0.375 (9.53 mm)

19.250(488.95 mm)

(From Perry R.H and Green, Don (1984), “Perry’s Chemical Engineer’s Handbook”, 7th

Edition, McGraw-Hill Book)

5.2.13 Standard Flanges

279

Page 280: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Flanges used in this design are chosen from the standard flanges. Here standard

flanges are adapted from the British standard (BS 4504), nominal pressure 10 bar.

Figure 5.3 Standard Flange

Standard flange for inlet isobutane

Diameter isobutane inlet pipe = 97.60 mm

Used standard o.d pipe = 114.3 mm

Table 5.5 : Standard Flange for Inlet isobutane

nom. pipe Flange Raised face Bolting Drilling Necksize o.d D b hi d4 f No. d2 k d3 h2 r

d1

100 114.3 210 16 45 148 3 M16 4 18 170 130 10 8

Standard flange for outlet isobutane

Diameter isobutane outlet pipe = 116.72 mm

Used standard o.d pipe = 114.3 mm

280

Page 281: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 5.6 : Standard Flange for Outlet isobutane

nom. pipe Flange Raised face Bolting Drilling Necksize o.d D b hi d4 f No. d2 k d3 h2 r

d1

100 114.3 210 16 45 148 3 M16 4 18 170 130 10 8

Standard flange for inlet steam

Diameter steam inlet pipe = 488.94 mm

Used standard o.d pipe = 508 mm

Table 5.7 : Standard Flange for Inlet Steam

nom. pipe Flange Raised face Bolting Drilling Necksize o.d D b hi d4 f No. d2 k d3 h2 r

d1

500 508 645 24 68 570 4 M20 20 22 600 538 15 12

Standard flange for outlet steam

Diameter steam outlet pipe = 544.79 mm

Used standard o.d pipe = 508 mm

Table 5.8 : Standard Flange for Outlet Steam

nom. pipe Flange Raised face Bolting Drilling Necksize o.d D b hi d4 f No. d2 k d3 h2 r

d1

500 508 645 24 68 570 4 M20 20 22 600 538 15 12

5.2.14 Design of Saddles

Table 5.9: Using Ds = 600mm, the standard steel saddles for vessels up

to 1.2m :

281

Page 282: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Vessel

diamete

r (m)

Maximum

weight

(kN)

Dimension (m) mmV Y C E J G t2 t1 Bolt diameter

0.9 56.38 0.63 0.15 0.81 0.34 0.275 0.095 10 6 20

5.2.15 Baffles

Type : transverse baffle

Baffle diameter for plate shell is given as, Ds = the nominal diameter of the shell for

plate shell. So baffle diameter = 0.600 m = 23.63’ = 600 mm

Diameter of tube holes in baffles, Dh

Dh = outer diameter of the tube

= (0.16 + 1/32) x 20.2

= 3.86 mm

Number of baffle segmental, Nb

Nb = length tube / inside diameter shell

= 4880 / 600

= 8.13 ≈ 8 baffles

Vent and drain -A drain and vent connection shall be provided on the shell side

Table 5.10: Summary Of Mechanical Design For Heat Exchanger In Series

Heat Exchanger E100

282

Page 283: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Design pressure, bar 11

design temperature, oC 277

Material Of Construction Tube side: Carbon steelShell side : Carbon steel

Minimum Thickness Of Cylindrical Section Of The Shell, mm

6.0

Longitudinal Stress,

N/mm2

55.0

Circumferential Stress

N/mm2

27.5

Minimum Thickness Of Tube Wall, mm

5.91

Minimum Thickness Of Head And Closure,

8.80

Minimum Thickness Of The Channel Cover,mm

33.0

Design Load, kN 56.38Diameter pipe for isobutene inlet and outlet, mm

100

Diameter pipe for steam inlet and outlet, mm

500

Vessel diameter, m 0.9Types of baffles transverse Number of baffle segmental, Nb

8

REFERENCES

D. Brian Spalding, J.Taborek, “Heat Exchanger Design Handbook, Volume 1

- Heat Exchanger Theory”, Hemisphere Publishing Corporation, Washington, New

York, London, 1983.

283

Page 284: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

D. Brian Spalding, J.Taborek, “Heat Exchanger Design Handbook, Volume 2

- Fluid Mechanics and Heat Transfer”, Hemisphere Publishing Corporation,

Washington, New York, London, 1983.

J. M. Chenoweth, D. Chisholm, R. C. Cowie, D. Harris, A. Illingworth, J. F.

Lancaster, M. Morris, I. Murray, C. North, C. Ruiz, E. A. D. Sauders, K. V. Shipes, J.

Dennis Usher, R. L. Webb, “Heat Exchanger Design Handbook, Volume 4 -

Mechanical Design of Heat Exchangers”, Hemisphere Publishing Corporation 1983,

Washington, New York, London, 1983.

D. K. Edwards, P. E. Liley, R. N. Maddox, Robert Matavosian, S. F. Pugh, M.

Schunk, K. Schwier, Z. P. Shulman, “Heat Exchanger Design Handbook, Volume 5

- Physical Properties”, Hemisphere Publishing Corporation 1983, Washington, New

York, London, 1983.

E. A. D. Saunders, B. Sc. C. Eng., M. I. Mech. E. “Heat Exchangers,

Selection, Design and Construction”, Longman Scientific and Technical, 1998.

Yokell, Stanley, “A working Guide to Shell and Tube Heat Exchangers”,

McGraw-Hill Publishing Company, 1990.

Sadik Kakac, Hongtan Cin, “ Heat Exchangers, Selection, Rating, and

Thermal Design”, CRC Press, Boca Raton, Boston London New York, Washington,

D.C, 1998.

Gupta, J. P., “Working With Heat Exchangers: question and answers”,

Hemisphere Publishing Corporation, A member of the Taylor and Francis Group, 1990.

Warren D. Seider, J.D. Seider, Daniel R. Lewin, “Process Design Principles,

Synthesis, Analysis and Evaluation”, 1997.

Stanley M. Wales, “Chemical Process Equipment, Selection and Design” ,

Butterworths Series in Chemical Engineering, 1990.

Frank P. Incropera, David P. Dewitt, “Fundamentals of Heat and mass

Transfer”, 5th Edition, John Wiley & Sons, Inc, 2002.

Holman, J.P, “Heat Transfer”, 7th Edition, McGraw-Hill, Inc, 1992.

Kern. D.Q, “Process Heat Transfer”, International Editions, McGraw-Hill, Inc,

1965.

Perry R.H and Green, Don, “Perry’s Chemical Engineer’s Handbook”, 7th

Edition, McGraw-Hill Book Company, Singapore, 1984.

Bhattacharya, B.B, “Introduction to Chemical Equipment Design,

Mechanical Aspects”, Indian Institute of Technology, 1976.

284

Page 285: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Holman, J.P. “Heat Transfer”, 7th Edition, McGraw-Hill, Inc, 1992.

Kern. D. Q “Process Heat Transfer”, International Editions, McGraw-Hill, Inc,

1965.

Perry R.H and Green, Don, “Perry’s Chemical Engineer’s Handbook”, 7th

Edition, McGraw-Hill Book Company, Singapore, 1984.

Sinnott, R. K., Coulson & Richardson, “Chemical Engineering Volume 6,

Chemical Engineering Design”, Butterworth Heinemann, 1999.

Carl R. Branon, “Rules Of Thumb For Chemical Engineers”, Gulf Publishing

Company, 1994.

Perry R.H and Green, Don, “Perry’s Chemical Engineer’s Handbook”, 7th

Edition, McGraw-Hill Book Company, Singapore, 1984.

Sinnott, R. K., Coulson & Richardson, “Chemical Engineering Volume 6,

Chemical Engineering Design”, Butterworth Heinemann, 1999.

Peters, max Stone, “Plant Design and Economics for Chemical Engineers”,

2nd Edition, McGraw-Hill Chemical Engineering Series, 1968.

CHAPTER 2

285

Page 286: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

PROCESS CONTROL AND INSTRUMENTATION

2.1 INTRODUCTION

All processes are subject to disturbances that tend to change operating conditions,

compositions and physical properties of the streams. In order to minimize those ill

effects that could result from such disturbances, chemical plants are implemented with

substantial amounts of instrumentation and automatic control equipment. In critical

cases and in especially large plants, moreover, the instrumentation is computer

monitors for convenient, safety and optimization.

A chemical plant is an arrangement of processing unit. The plant overall

objective is to convert the raw materials into desired product using available sources of

energy in the most economical way. All operating unit should be monitored. Methods of

limiting hazard levels by control features include sensoring control on limits and various

aspects of sequential and continuous monitoring.

In control situations, the demand for speed of response may not be realizable

with an overly elaborate mathematical system. Moreover, in practice, not all

disturbances are measurable and the process characteristics are not known exactly.

Accordingly, feedforward control is supplemented in most instances with feedback. In a

well-designed system, typically, 90% of the corrective action is provided by feed

forward and 10% by feedback with the result that the integrated error is reduces by a

factor 10%. The main types of instrument used for chemical process plants are flow

controller, temperature controller, pressure controller and level controller.

2.2 OBJECTIVES OF CONTROLL

The most important objectives of the designer when specifying control and

instrumentation schemes are:

1. Safe Plant Operation

286

Page 287: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

• To keep the process variables within known safety operating limits and

within allowable limits.

• To detect dangerous situations as they develop and to provide alarms

and automatic shut down system.

• To provide interlocks and alarms to prevent unsafe operating

procedures.

2. Production Specification

• To achieve the design product output

• To produce the desired quality of final product

• To keep the product composition within the specified quality

standards.

3. Economics

• To operate at the lowest production cost, commensurate with the other

objectives.

• The operation of the plant must conform to the market condition, which

is availability of raw materials and demand of the final product.

4. Environmental Regulations

• Variable controlled must not exceed the allowable limits set by various

federal and state laws.

5. Operational Constraint

• Various type of equipments used in chemical plant have constrains

inherent to their operation. Such constraints should be satisfied

throughout the operation of plant.

• Control systems are needed to satisfy all these operational constrains.

In a typical chemical processing plant these objectives are achieve by combination

of automatic control, manual monitoring and laboratory analysis.

2.3 CONTROL SYSTEM DESIGN SHEET

2.3.1 Heat Exchanger (E-100)

287

Page 288: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.1: Control Scheme for the Heat Exchanger

Table 2.1: Parameter at Heat Exchanger

2.3.2 Catalytic Cracking Fluidized Bed Reactor (op-100)

Intention: To Heat Up the reactant Before Entering ReactorObjective : To heat up the reactants to 250 oC

Objective Measurable Disturbances Action Set PointVariable

1. To control Temperature at Change in Control temperature E-100 temperature of outlet stream flow rate of the heating by V3 at Temperature outlet stream S4 feed steam inlet S3 250oC

288

Page 289: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.2: Control Scheme for Catalytic Cracking Fluidized Bed Reactor

Table 2.2: Parameter at Catalytic Cracking Fluidized Bed Reactor

Intention: To Separate Vapor and Liquid from Stream Leaving Heat Exchanger

Objective Measurable

Variable

Disturbances Action Set Point

1. To control flow Flow of gas Change in flow Control flowrate of the Stream S4 inside phase in phase to of gas in phase Input stream S4 by reactor reactor of reactor controlling V32. To control solid Solid in and Change of solid Control solid in and 95679.8kg flow to relate out in the flow rate moving solid out in the speed and flow rate reactor and to reactor and reactor and

regenerator regenerator regenerator3. To control flow rate of Change of feed Control pressure by 2.89 bar pressure between feed into reactor flow rate opening or closing reactor and and regenerator valve by adjusting V5 regenerator4. To control Temperature in Change of Control temperature 180oC temperature reactor and temperature by opening or closing in reactor regenerator In reactor and valve at the air feed

regenerator V4 and product V6

2.3.3 Control at Compressor (C-101)

289

S7

Page 290: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.3: Control Scheme for the Compressor

Table 2.3: Parameter at Compressor

Intention: To maintain the pressure inside the compressorObjective : To keep pressure maintain at bar

Objective Measurable Disturbances Action Set PointVariable

To maintain Pressure Power or duty Control pressure C-101pressure inside inside of the by adjusting V8 at pressurecompressor compressor compressor steam inlet S7 bar

2.3.4 Control at Condenser

290

S8

Page 291: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.4: Control Scheme for the Condenser

Table 2.4: Parameter at Condenser

Intention: To maintain the pressure inside the compressorObjective : To keep pressure maintain at bar

Objective Measurable Disturbances Action Set PointVariable

1. To control Temperature at Change in Control temperature E-100 temperature of outlet stream flow rate of the heating by V9 at Temperature outlet stream S9 feed steam inlet S8 50oC

2.3.5 Separator (V-100)

291

Page 292: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.5: Control Scheme for the Separator

Table 2.5: Parameter at Separator

Intention: To Separate Vapor and Liquid from Stream Leaving Heat ExchangerObjective Measurable Disturbances Action Set Point Variable 1. To control level Level of liquid Change in level Control level by Stream inside phase in phase of liquid in phase V10 at inlet stream S9 of separator separator separator S9 liquid height1. To control Maintain Change in Control pressure by Pressure pressure pressure pressure opening and closing 0.5 bar phase separator in phase of liquid in phase valve by V28 at

separator separator stream S10 1. To control Flow rate at Change in the Control Flow at the Flow into Flow rate the bottom of flowrate of bottom by V27 at The feed inside phase the separator the separator stream S11 At stream separator S11

292

Page 293: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2.3.6 Fixed Bed Reactor (R-101)

Figure 2.6: Control Scheme for the Fixed Bed Reactor

Table 2.6: Parameter at Fixed Bed Reactor

Intention: To React Isobutene with Methanol to Produce MTBEObjective Measurable Disturbances Action Set Point

Variable To regulate

reactor

temperature

Cooling

water make

up rate

Reactant feed

temperature and

composition

Control temperature

by V13

Set the

temperature

at 53.3 oCTo maintain

constant

pressure at the

feed stream

Pressure in

the fed of

stream S15

Pressure feed to

the reactor

Control the pressure

in the reactor by

control of V29

Pressure at

1 bar

2.3.7 Distillation Column (T-101)

293

V13

V29

Page 294: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.7: Control Scheme for the MTBE Distillation Column

Table 2.7: Parameter at MTBE Distillation Column

Intention: To Separate MTBE from Mixture Leaving ReactorObjective Measurable Disturbances Action Set Point Variable 1. To control level Level of liquid Change of level Control level by Stream S19 inside column in column of column Adjusting V17 at valve at raffinate outlet 15251.9kg/hr Stream S19 2. To control Temperature Change of Control temperature by 61.2oC temperature inside column temperature Control V16 inside column in column 3. To control Level in drum Change of level Control level by V15 Stream level in drum in drum to maintain the S17 at Product output 38747.97kg/hr

2.3.8 Liquid-Liquid Extraction Column (T-100)

294

Page 295: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.8: Control Scheme for the Liquid-liquid Extraction Column

Table 2.8: Parameter at Liquid-liquid Extraction Column

Intention: To Extract Methanol and Water from Hydrocarbon

Objective Measurable Disturbances Action Set Point

Variable

To control flow flow of liquid Change of level Control flow by adjust Stream

at stream S20 in column of column Valve V19 at bottom S20 at

outlet stream 40.32kg/hrTo control flow at

stream S21

Flow of liquid in

column

Change of flow of

liquid extraction

Control at V20 to keep

the flow inlet maintain

Flow inlet at

stream S21To control level at the

raffinate

Product of S24

Level of liquid

going out of the

column

Change of level in

the column

Maintain the level by

control V21 at stream

S24

Level output at

raffinate section

S24To control the density

intermediate between

methanol and water

Density level

change between

water and

methanol

Change of the

interfacial of level

between two

phase

The bottom stream

removed by control

V22

Interfacial level

at bottom

product at

stream S26

2.3.9 Distillation Column (T-102)

295

Page 296: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Figure 2.9: Control Scheme for the Distillation Column

Table 2.9: Parameter at Distillation Column

Intention: To Separate Methanol and waterObjective Measurable Disturbances Action Set Point Variable 1. To control level Level of liquid Change of level Control level by Stream inside column in column of column opening and closing S28 : at valve V25 at bottom 63.4453kg/hr outlet stream2. To control Temperature Change of Control temperature by 62.17oC temperature inside column temperature opening or closing inside column in column Valve 24 at top outlet stream 3. To control Level in drum Change of level Control level by V23 Stream level in drum in drum opening or closing S27 valve at reflux stream

296

Page 297: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

2.3.10 Mixer (MIX-100)

Figure 2.10: Control Scheme for the Mixer

Table 2.10: Parameter at Mixer

Intention: To Mix Methanol from Recycle and Make Up MethanolObjective Measurable Disturbances Action Set Point Variable 1. To control the Flowrate of Change of Control flowrate M - 101 flowrate the reactant flowrate to the bypass valve Stream S14 reactor V12 at 2.88 m3/hr

297

Page 298: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

2.3.11 Expander (EX-100)

Figure 2.11: Control Scheme for the Expander

Table 2.11: Parameter for Expander

Intention: To Expand the Pressure Leaving the ReactorObjective Measurable Disturbances Action Set Point Variable 1. To expand the Pressure Change of Control pressure by Pressure pressure inside the pressure adjusting valve V14 0.45 expander

38

Page 299: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Figure 2.13 : PFD Diagram Before Control

39

Page 300: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Legend- Process Flow PC - Pressure Control ILC - Interfacial Level Control

- Control Flow FC - Flow Control LC - Level control

- Temperature Control TI - Temperature Indicator DPC - Differential Pressure Control

Figure 2.13 : Process Control P and ID Diagram

TC

40

Page 301: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

41

Page 302: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

REFERENCES

Luyben, W. l., (1990), Process Modelling simulation and Control for Chemical

Engineers, 2nd Edition, McGraw-Hill Chemical Engineering Series

Ogunnaike, B. A. and Ray, W. H. (1994), Process Dynamics, Modeling and

Control, New York, Pxford.

R.K.Sinnott, 1999.Chemical Engineering Design, Coulson & Richardson Chemical

Engineering .3rd Edition. Volume 6 .Britain. Butterworth Heinemann

J.R Backhurst & J.H Harker.1987.Chemical Engineering Design, Coulson &

Richardson Chemical Engineering .3rd Edition. Volume 2 .United Kingdom.

Pergamon Press.

Stanley M. Walas. 1988. Chemical Process Equipment Selection and Design.

United State of America. Butterworth’s Series in Chemical Engineering.

Chemical Engineering Progress, February 2001, American Institute of Chemical

Engineering.

42

Page 303: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

CHAPTER 3

SAFETY CONSIDERATION

3.1 INTRODUCTION

Any organization has a legal and moral obligation to safe guard the health and

welfare of its employees and the public. Safety is also good business: the good

management practices needed to ensure safe operation would also ensure efficient

operation.

All manufacturing processes there are additional, special, hazard associated

with the chemical used and the process condition. The designer must be aware of

these hazards and ensure through the application of sound engineering practices

that the risks are reduced to acceptable levels.

Safety and loss prevention in process design can be considered under the

following broad headings :( Coulson and Richardson’s Volume 6)

1. Identification and assessment of the hazards

2. Control of the hazards; for example by containment of flammable and toxic

materials

3. Control the process. Prevention of hazardous deviation in the process

variables, (pressure, temperature, flow) by provision of automatic control

system interlocks, alarms, trips, together with good operating practices and

management.

4. Limitation of the loss. The damage and injury caused if an incident occurs,

pressure relief, plant layout, provision of fire-fighting equipment.

In Malaysia, The Occupational Safety and Health Act, 1994 is a tool which

provided a new legal and administrative as a driving force to promote, encourage

and stimulate the high quality standards of health and safety at work place. Both

parties such as employers and employees must give their support and cooperate to

43

Page 304: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

comply the law and not misuse safety in order to increasing the promotion of safety

awareness and effective safety organization and performance in companies.

3.2 HAZARD AND OPERABILITY STUDY

HAZOP stands for “hazard and operability studies.” This is asset of formal hazard

identification and elimination procedures designed to identify hazard to people,

process plants and the environment. The techniques aim to stimulate in a

systematic way the imagination of designers and people who operate plants or

equipment so they can identify potential hazard. In effect, HAZOP studies make the

assumption that hazard or operating problem can arise when there is a deviation

from the design or operating intention. Corrective actions can then be made before

a real accident occurs.

The primary goal in performing a HAZOP study is to identify, not analyse or

quantify, the hazard process. The end product of a study is a list of concerns and

recommendation for prevention of the problem, not an analysis of the occurrence,

frequency, overall effects, and the definite solution. If HAZOP is started too late in a

project, it can lose effectiveness because:

1. There may be a tendency not to challenge an already existing design.

2. Changes may come too late, possibly requiring redesign of the process.

3. There may be loss of operability and design decision data used to generate

the design.

HAZOP is a formal procedure that offers a great potential to improve the

safety, reliability and operability of process plants by recognizing and eliminating

potential problems at the design stage. It is not limited to the design stage,

however. It can be applied anywhere that a design intention. (Perry’s Handbook,

1998)

When using the operability study technique to vet a process design, the

action to be taken to deal with a potential hazard will often be modification to the

control system and instrumentation, the inclusion of additional alarms, trips or

interlock. If major hazard are identified, major design changes may be necessary,

alternatives processes, material and equipment. In order to have a safe process

successfully producing to specification to the required product, a sound control

system is necessary but not sufficient. (Coulson & Richardson’s, 1999).

44

Page 305: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

The objectives of HAZOP study are:

1. To identify areas of the design that may posses a significant hazard

potential

2. To identify and study features of the design that influences the probability of

a hazardous incident occurring.

3. To familiarize the study team with the design information available.

4. To ensure that a systematic study is made of the areas of significant hazard

potential.

5. To identify design information not currently available to the team.

6. To provide a mechanism for feedback to the client of the study team’s

detailed comments. (Sydney Lipton and Jeremiah Lynch, 1994)

The advantages of HAZOP study to the design application:

• Early identification of problems areas when conceptual design stage.

• Identifies need for emergency procedures to mitigate.

• Provide essential information for safety case, such as on the hazards

identified and effectiveness of safety systems.

• Through examination of hazard and operability problems when applied at

detailed stage.

• Meets legislative requirements.

• Identifies need for commissioning, operating and maintenance procedures

for safe and reliable operations.

45

Page 306: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Table 3.1: A HAZOP study contains the following important features:

Features : Meaning :Intention Defines how the part or process is expected to

operate.Guide words Simple word used to qualify the intention in order to

guide and stimulate creative thinking.Deviations Departures from the intention discovered by

systematic application of guide words.Causes Reasons that deviations might occur.

Consequences Results of deviations if they occur.Action Prevention, mitigation and control

- Prevent causes.

- Mitigate the consequences.

- Control action such as provide alarms to indicate

things getting out of control: define control actions

to get back into control.

The MTBE Plant HAZOP Study is included at Appendix: Safety.

3.3 PLANT START UP AND SHUT DOWN PROCEDURE

Safe procedures must be well known for the start up and shut down of plant and

deviations from normal operating conditions. Whenever process conditions are

changed, opportunities are presented for hazardous situations to arise. Building up

the process consistency may reduce the investigating breakdown and malfunction,

availability, the design cycle, operability, flexibility including blending and recycling

experience and known how personnel.

The start-up and shutdown of the plant must proceed safely and easily, yet

be flexible enough to be carried out in several ways. The operating limits of the

plant must not exceed and dangerous mixtures must not be formed because of

abnormal states of concentration, temperature, phase, reactant, catalyst and

products.

During start-up, the catalyst in the reactor should be activated and

sufficiently warm for reaction to begin when the flow of reactant is started.

Contaminants often enter the system at this stage. Materials are added by

operations such as purging, drying and flushing. Water and other materials may

46

Page 307: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

condense in unplanned location causing process levels to get out of control and

other problems. The ignition of fuel to heat the high temperature fluid during start-up

must be designed to accomplish this safely Some typical errors that could occur

during start-up of the plant include :

1. Wrong routing, involving failure to ensure that correct valves are closed.

This is especially crucial in the adsorption section where three different

processes are occurring at any one time.

2. Drain valves are left open resulting in loss of material and possibly

endangering the lives of workers.

3. Valves left closed resulting in over pressure in the vessel.

4. Failure to complete purging cycle before admission of fuel air mixture.

5. Backflow of material from high pressure to low pressure system.

6. Setting of wrong valves for operating parameters such as jacket

temperature in the reactor and reflux in the distillation column.

3.3.1 Normal Start up and Shut down the Plant

The study of the plant start up and shut down must include investigation of the

operating limits, transient operating conditions, process dynamics, contamination

and added material, emissions, hot standby and emergency shut down with plant

protection control systems and alarms.

3.3.1.1 Operating Limits

The operating limits of the plant are imposing by mechanical, electrical, civil and

process design. Where necessary, it has to be introduce additional equipment,

sampling points, instrumentation and lines, and identify their use on the engineering

line diagram,

3.3.1.2 Transient Operating and Process Dynamic

The transient operating conditions must be studied to safe time and operating cast.

The process dynamics that to be investigated includes excessive heat transfer

47

Page 308: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

when more or less floe in either energy exchanging streams through activations and

warming of catalyst when the flow of reactant starts to entrance of contamination

and others

3.3.1.3 Added Materials

Materials are added by operations may not be tolerated in part of the system or

clean material may be needed for the start up of the plant. Residues or unwanted

products such as out of specification may be discharged or hold in tank for further

treatment.

3.3.1.4 Hot Standby

Time is save during restart up if plant are kept partially working such as when other

unit operation are ceased to function temporarily, the converter can be left in hot

standby conditions.

3.3.1.5 Emergency Shut Down

Special plant protection known as process trip system or emergency shut down

system is design to affect the emergency shut down through the push button by

operator or from automatic activation of a relay when necessary. The trip systems

should be reliable and operate when required to avoid a nuisance shut down of

plant.

3.3.2 Start up and Shut down Procedure for the Main Equipment

3.3.2.1 Reactor

1. It is recommended that the internal reactor vessel measurements (ID, Bed

Depth – not the overall vessel height, etc.) be verified, so that product

loading is consistent with the "Estimated Performance Sheet" (EPS).

2. Prior to any loading, it is necessary to make an internal and external

inspection of the reactor vessel. In other words, there should not be any

pipes or hollow devices in the vessel, which could allow the gas to travel

without contacting the product.

48

Page 309: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

3. There are two vessel types of bed supports that can be used; (1) has a

support grid permanently installed about 2 inches below the throat of the

lower manway; or (2) uses a level bed of washed gravel, ceramic balls, or

pawl rings. The bed support must be leveled.

4. Close and secure the bottom manway.

5. Through the top manway, load the remaining feed to level as stated in the

EPS. During the latter stages of loading level off the cone of the filled

product bed and continue loading until finished.

6. Close and secure the top manway.

Upon operational start-up, record the required measurements – temperature,

pressure, and flow rate - from each bed (if applicable). This data should be kept on

some routine basis (daily, weekly bi-weekly, etc.) so that any problems that might

develop can be identified and corrected.

3.3.2.2 Distillation Column

Start-Up Procedure

1. Turn the switch box indicator to Distillation Control setting.

2. Switch the column power source lever to the "on" position. Turn the Reboiler

Heater Control knob clockwise. This prevents over heating of the reboiler.

3. Turn on the cold water supply ( CWS )valve until the computer stops telling

the user to increase the volume of the CWS valve.

4. Adjust the Reflux Control to the desired setting.

5. Assure all computer settings are as desired.

6. Allow the tray temperatures to reach a steady-state value.

7. Turn on the feed and reboiler pumps as applicable. The pump settings can

be adjusted on the computer.

Caution: DO NOT ALLOW THE WATER LEVEL TO FALL BELOW THE

CALROD HEATERS.

49

Page 310: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

This will result in damage to the heaters. If the heaters are exposed turn off the

column, this allows the vapor in the column to condense and return to the

reboiler. If the liquid level is still below the heaters, more liquid must be added to

the reboiler.

Shut-Down Procedure

1. Turn the Reboiler Heater Control knob to zero.

2. Turn off the pumps (feed and reboiler).

3. Turn off the CWS valve when the temperature of the distillate is below the

boiling point of the light component of the mixture.

4. Press the stop button.

5. Shut off the computer, by selecting the "Shut-down" option from the Special

menu.

3.3.2.3 Liquid-Liquid Extraction Column

Start Up Procedure

1. Check to see that all the drainage valves are closed.

2. Check to be sure the top water vent valve is open.

3. When the liquid level in the column reaches the top right nozzle(water in

nozzle), turn the water flowrate down to the desired setpoint. Turn on and

set the feed flowrate to the desired setpoint by adjusting the pump speed,

and close the top water vent.

4. Allow the interface to form between the top mesh and the top left nozzle.

5. Small adjustments should be made in order to keep the interface constant.

Shut down procedure

1. Turn off all inlet flowrates on the right control panel.

2. Shut off the stirrer on the right control panel.

50

Page 311: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

3. Open the top water in vent valve.

4. Open the bottom centre black valve to drain the column.

3.3.2.4 Heat Exchanger

Start up Procedure

When putting a heat exchanger in operation, open the vent connections and

slowly start to circulate the cold medium only. Be sure that the entire cold side

of the exchanger is completely flooded before closing its vents. The hot medium

should then be gradually introduced until all passages are filled with fluid. Then

close the hot side vents and slowly bring the unit up to its operating

temperature.

Shut down Procedure

When heat exchanger is required to be shutdown, the hot fluid should be turned

off first. If it is necessary to stop the circulation of the cold fluid, the hot medium

should also be stopped by by-passing the heat exchanger.

3.4 EMERGENCY RESPONSE PLAN (ERP)

It is expected that every person who working in this plant will act responsibly in any

Department of Emergency. ERP procedures were state in Appendix: Safety. In most cases,

the observer of an emergency is faced with decision to leave the scene to summon help or

stay and provide help. The basic rule is as follows.

“Unless we are sure that we are not putting ourselves in any danger and we know we can

make a difference, summon help.

3.4.1 Emergency Response Procedures

General Procedures

51

Page 312: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

When alarm system is activated whether by break glass or by smoke detector, the

alarm that is siren sound will be triggered throughout plant. The following general

procedures should be followed if there is no immediate emergency in your area.

• Do not panic and stay alert:

Stay calm and be alert and ready to response to any emergency according

to the

Plant Emergency Organization Programmed. The shift manager should go

to the security guard to identify the location of the alarm.

• Access the situation around your area :

Look around and ensure that your immediate area is not in danger or affected by

the emergency. Stop all contractors from working immediately.

• Wait for instruction from Supervisor/Shift Manager :

Do no evacuate from one’s post unless one is immediate danger or when instructed

by one’s supervisor or the shift manager.

• Avoid using the telephone :

Do not use the telephone unless it is absolutely necessary, as the telephone lines

must be reserved for calling emergency services. All incidents resulting in

injuries, property damage and/ or productions loss shall be investigated and

reported for within 24 hours. Corrective action to prevent the recurrence of

the incident shall be initiated 48 hours.

3.4.2 Evacuation Procedures:

• Exit building via the stairways :

It takes time to the person familiarize with evacuation routes in advance.

The maps showing the location of all emergency exits and extinguishers are

posted on all floors.

• Assist the injured when possible :

Do not move the seriously injured unless there is danger of further injury. If it

is necessary to leave someone in the building, try to leave him in a relatively

secure place (example, the stairwell is one of the safer places to be in fire).

After someone has been evacuated the building, find the proper officials and

report the location and condition of persons who need assistance.

• Designed persons are responsible for clearing the production floors and

offices :

52

Page 313: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Efforts to clear the production floor and offices should be limited to 5

minutes. As the areas are cleared, all doors should be closed.

• Once outside the building :

Keep at least 50 feet away from the building to avoid danger from falling

glass, example “Evacuate to the Emergency Assembly Area “.

• Do not re – enter the building until safety officer or fire personnel have been

determined that it is safe.

3.4.3 Fires:

• If the fire alarm sounds or a fire broke out in the plant, turn off any electrical

equipment that been operating and evacuate the building immediately.

Close all doors to help prevent fires from spreading. Exit via stairwells.

• Call 994 to give location and extent of fire and notify the management to

report the fire :

State if there are any special circumstances, such as the presence of

dangerous chemicals.

• Don’t attempt to fight a fire unless we have been trained in fire extinguisher

use and the fire is very small :

When fighting a fire, always position ourselves between the exit and the fire

to ensure an escape route. IF THE FIRE CANNOT BE CONTAINED, GET

OUT QUICKLY!

3.4.4 Explosion, Line Rupture or Serious Leak

• Do the following if possible.

1. Turn the “Emergency Stop” switch to “Off” position

2. Isolate the effected area of the limit. Block in high-pressure source

as required accomplishing this.

3. Complete the shut down

3.4.5 Other Emergencies :

• Injuries :

53

Page 314: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

For life – threatening emergencies, CALL 991 for medical aid and for

transportation to hospital and at same time notify the management as listed

on the Notification Lists. For less serious injuries or illness, first aid can be

obtained at the nearest clinic. Report all injuries to the management.

• Equipment failures :

Any equipment failures, which may harm or injured the workers, should be

reported to the Production Supervisors or the management for further action

to be taken.

3.5 PLANT LAYOUT

The process units and ancillary buildings should be laid out to give the most

economical flow of material and personnel around the site. Hazardous process

must be located at a safe distance from other buildings. Consideration must be also

being given to the future expansion of the site. The ancillary buildings and services

required on site, in addition to the main processing units (building) will include:

(Coulson and Richardson’s 1999)

1. Storage for raw materials and products; tank farms and warehouses

2. Maintenance workshop

3. Stores, for maintenance and operating supplies

4. Laboratories for process control

5. Fire stations and other emergency services

6. Utilities: steam boilers, compressed air, power generation, refrigeration,

transformer stations.

7. Effluent disposal plant

8. Offices for general administration

9. Canteens and other amenity buildings, such as medical centres

10. Car parks

Normally, the process units will be sited first and arranged to give a smooth

flow of materials through various processing steps, from raw material to final

product storage. It is normally spaced at least 30 apart and for hazardous

processes, the greater spacing may be needed. Then, the principal ancillary

buildings to be located and arranged in order to minimize the time spent by the

personnel in travelling between the buildings. The administration offices and

54

Page 315: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

laboratory should be located well away from potentially hazardous processes since

a many people be in here. The control rooms normally are located adjacent to the

process units but if it with the potentially hazardous processes has to be sited at

safer distance.

Besides that, the layout of the plant roads, pipe alleys and drains also must

be considered to locate the main process units. Easy access roads will be needed

to each building for construction and for operation and maintenance. The utilities

buildings should be sited to give most economical run of pipes to and from the

process units. Finally, the main storage areas should be placed between loading

and unloading facilities and the process units they serve. Storage tanks containing

hazardous materials should be sited at least 70 m (200 ft) from the site boundary.

There are 7 principal factors to be considered :

1. Economic considerations: construction and operating costs.

2. The process requirements.

3. Convenience of operation.

4. Convenience of maintenance.

5. Safety.

6. Future expansion.

7. Modular construction.

The MTBE site layout have shown in Figure 3.1.

55

Page 316: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Figure 3.1 Methyl tert-Butyl Ether (MTBE) Plan Layout

U

56

Page 317: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Figure 3.2: Methyl tert-Butyl Ether (MTBE) Plant Evacuation Routes U

Legand Evacuation Routes

57

Page 318: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Figure 3.3 PID before HAZOP

58

Page 319: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON MTBE PER YEAR

Figure 3.4 PID after HAZOP

59

Page 320: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

REFERENCES

Clarles A.Wentz, 1998. Safety, Health and Environmental Protection. United State of

America:McGraw-Hill.

R.K.Sinnot, 1999. Chemical Engineering Design. Coulson & Richardson’s Chemical

Engineering 3rd Edition. Volume 6. Britain; Butterworth Heinemann.

Robert H. Perry, Don W. Green, 1998 Perry’s Chemical Engineer’s Handbook, Seventh

Edition, McGraw-Hill.

http://www.sulfatreat.com/Documents/HTML/St/startup.html

http://www.amberjet.com/IP/start_up.htm

http://www.sulfatreat.com/Documents/PDF/SulfaTreat/ST-Start_Up_Procedure.pdf

http://chem.engr.utc.edu/Webres/435F/Proc.htm

http://www.eng.buffalo.edu/Courses/ce428/Distillation/procedure.htm

http://users.rowan.edu/~savelski/uol/liqliq.html

http://pharmaflo.com/heatexch/

60

Page 321: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 4

ECONOMIC EVALUATION

INTRODUCTION

Economic evaluation is very important for a proposed plant. We have to be able to

estimate and decide between alternative designs and for project evaluation. Chemical

plants are built to make a profit an estimate of the investment required and the cost of

production are needed before the profitability of a project can be assessed. The total

investment needed for a project is the sum of the fixed and working capital. Fixed

capital is the total cost of the plant ready for start up. It is the cost paid to the

contractors. Working capital is the additional investment needed, over and above the

fixed capital, to start the plant up and operate it to the point when income is earned.

Most of the working capital is recovered at the end of the project.

61

Page 322: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.1.1 The Specification Of Plant

In this chapter, the costing of equipment which has been designed will be

estimated and the feasibility of MTBE production will be evaluated by

profitability analysis to make sure the project is economically attractive.

There are some general assumptions to this chapter;

i. The plant life span is fifteen years.

ii. The currency exchange rate of US dollar to Ringgit Malaysia is fixed at 3.8 as

fixed by Malaysian Government.

iii. The price of raw materials, catalyst and product is fixed for the whole period of

operation.

Price of raw material : Isobutane - RM 0.8094 / kg

: Methanol - RM 0.988 / kg

Price of product : MTBE - RM 1.320 / kg

: TBA - RM 1.035 / kg

: DME - RM 0.655 / kg

62

Page 323: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.1.2 Revenue From Sales

i. MTBE = 37878.76 kg/h = year

tonne300000

Price: RM 1.320/kg

= 90.0320.13652476.37878 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 394199710/yr

ii. TBA = 639.663 kg/h

Price: RM 1.035/kg

= 90.0035.136524663.639 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 5219612/yr

iii. DME = 1210.9868 kg/h

Price: RM 0.655/kg

= 90.0655.0365249868.1210 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 6253560/yr

iv. Isobutane = 13718.4558 kg/h

Price: RM 0.8094/kg

=

90.08094.0365244558.13718 ××××

kg

RM

year

day

day

hr

hr

kg = RM

87541714/yr

v. n-butane = 157.412 kg/h

Price: RM 0.35/kg

= 90.035.036524412.157 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 434363/yr

Total revenue = RM 493648959/yr

63

Page 324: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.2 COST ESTIMATION

4.2.1 Capital cost estimation

Capital cost estimates are essentially “paper and pencil” studies. The cost of making

an estimate indicates the personnel hours required in order to complete the estimate.

The capital needed to supply the necessary manufacturing and plant facilities is called

the fixed capital investment (FC), while the additional investment needed for the plant

operation (for plant start-up and operation to the point when income is earned) form the

working capital (WC).

Capital cost estimates for chemical process plants are often based on an estimate of

the purchase cost of the major equipment items required for the process, the other

costs being estimated as factors of the equipment cost. The accuracy of this type of

estimate will depend on what stage the design has reached at the time estimate is

made and on the reliability of the data available on equipment cost.

The cost of the purchased equipment is used as the basis of the factorial method of cost

estimation and must be determined as accurately as possible. It should preferably be

based on recent prices paid for similar equipment.

Calculation of total module cost and gross roots cost (based on table 4.2)

CTC = CFC + CWC + CL

Where,

CTC = total capital cost

CFC = fixed capital cost

CWC = working capital cost

CL = cost of land & other non-depreciable costs

FP = Pressure factor to account for high pressure

FM = Material factor to account for material of constructions

CP = Purchase cost for base condition

FBM = Bare module cost factor

64

Page 325: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CBM = Bare module equipment cost for base condition

C°BM = Bare module equipment cost for actual condition

Total Module Cost, CTM = 1.18 (∑C°BM )

= 1.18 (3223841)

= RM 3804132 x 3.8

= RM 14455703

Grass Root Cost, CGR = CTM + 0.35 ( ∑ CBM)

= 14455703 + 0.35 (12659343) x 3.8= RM 31292629

Since, Grass Root Cost (CGR) is:

CGR = CFC + CL

Area for 1 lot of land = 200000 m2

The price of land is RM 60 per m2

CL = RM 12000000

CFC = CGR - CL

= RM 31292629 - RM 12000000

= RM 19292629

Working capital is the additional investment needed over and above the fixed capital to

start the plant up and operate it to the point when income is earned.

Working capital cost = 5% of fixed capital costs

CWC = 5% fixed capital cost (CFC) (Coulson & Richardson,

= RM 964631 1990)

Thus,

Total capital cost (CTC) = CFC + CL + CWC

= RM 19292629+ RM 12000000+ RM 964631

= RM 32257260

65

Page 326: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.2.2 Manufacturing Cost Estimation

The cost of associated with the day to day operation of a chemical plant must be

estimated before the economic feasibility of a proposed process can be assessed.

The equation below is used to evaluate the cost of manufacture:

COM = 0.304FCI + 2.73COL + 1.23(CUT + CWT + CRM)

The cost of manufacturing (COM) can be determined when the following costs are

known or can be estimated:

1. Fixed Capital Investment (FCI): (CTM or CGR)

2. Cost of Operating Labor (COL)

3. Cost of Utilities (CUT)

4. Cost of Waste Treatment (CWT)

5. Cost of Raw Material (CRM)

4.2.2.1 Cost of Operating Labor (COL)

Table 4.1 Labor Cost

Equipment type

No of

equipment

Operators per shift per

equipment

Operator per

shiftHeat exchangers 6 0.1 0.6Reactor 2 0.5 1.0Vessels 1 0.0 0.0Pumps 5 0.0 0.0Compressor 2 0.15 0.3

Cost of manufacture (COM) = Direct Manufacturing Cost (DMC) +

Fixed Manufacturing Cost (FMC) +

General Expenses (GE)

66

Page 327: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Towers 3 0.35 1.05Waste Treatment 1 0.5 0.5

3.45Since, a single operators works on the average 48 weeks (3 weeks time off for

vacation and sick leave) a year, five 8-hour shifts a week.

1 operator =week

shift

Year

week 548 ×

=Year

shift240

Working days for MTBE plant is 7920 hour = 330 days

Operating shift per Year =days

operating

Year

days 3330 ×

=Year

shiftoperating990

Working days for MTBE plant is 7920 hour

So, the number operator needed =

Year

shiftYear

shiftoperating

240

990

= 4.125 operators

Thus,

Operating Labor = 4.125 operators x 3.45 operator per shift

= 14.23 operator

= 15 operator

A mechanical engineers maximum wages per year (MIDA 2002) RM 60,000.00

Thus,

Labor Cost (1996) = 15 x RM 60,000.00

= RM 900,000.00

67

Page 328: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.2.2.2 Cost of Utilities (CUT)

Yearly costs = flowrate x costs x period x steam factor

Since, assuming the plants operating days per year = 330 days

So,

Steam factor (SF) =yearperdaysofno

yearperoperatesplantsdayofno

.

'.

= 90.0365

330 =

1. Heater (E-100)

Duty = hrJGsJ 16113109542 .=

From table 8.5 (W.R Wan Daud, Princip Reka bentuk Proses Kimia, 2002, page

285) cost of heater RM 19.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.19

16.11 ××××yr

day

day

hr

GJRM

hr

GJ

= RM 1724515

2. Heater (E-101)

Duty = hrJGsJ 24123423874 .=

From table 8.5 (W.R Wan Daud, Princip Reka bentuk Proses Kimia, 2002, page

285) cost of cooling water RM 0.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.19

24.12 ××××yr

day

day

hr

GJRM

hr

GJ

= RM1891403

68

Page 329: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3. Compressor (C-100)

Power (shaft) = 137.73kW

Effeciency of drives, ξdr = 92.28% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

=92280

73137

.

.

= 149.25 kW

Yearly cost =

90.036524228.0

25.149 ××××yr

day

day

hr

kWhkW

= RM 268285

4. Cooler 1 (E-102)

Duty = hrGJsKJ 4144014590 .=

From table 8.5 (W.R Wan Daud, Princip Reka bentuk Proses Kimia, 2002, page

285) cost of cooling water RM 0.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.0

4.14 ××××yr

day

day

hr

GJRM

hr

GJ

= RM 68118

5. Cooler 2 (E-103)

Duty = hrJGsJ 12154204290 .=

From table 8.5 (W.R Wan Daud, Prinsip Reka bentuk Proses Kimia, 2002, page

285) cost of cooling water RM 0.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.0

12.15 ××××yr

day

day

hr

GJRM

hr

GJ

= RM71524

69

Page 330: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

6. Cooler 3 (E-104)

Duty = hrJGsJ 81503240 .=

From table 8.5 (W.R Wan Daud, Princip Reka bentuk Proses Kimia, 2002, page

285) cost of cooling water RM 0.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.0

8.1 ××××yr

day

day

hr

GJRM

hr

GJ

= RM 8514

7. Cooler 4 (E-105)

Duty = hrJGsJ 720240320 .=

From table 8.5 (W.R Wan Daud, Princip Reka Bentuk Proses Kimia, 2002,

page 285) cost of cooling water RM 0.6 / GJ.

Thus ,

Yearly cost = (Q) (C steam) (t)

= 90.0365246.0

72.0 ××××yr

day

day

hr

GJRM

hr

GJ

= RM 3406

8. Pump 1(P100)

Power (shaft) = 327.94kW

Effeciency of drives, ξdr = 93.71% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

= 9371.0

94.327

= 349.95kW

Yearly cost =

90.036524228.0

95.349 ××××yr

day

day

hr

kWhkW

= RM 629053

70

Page 331: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

9. Pump 2(P101)

Power (shaft) = 79.19kW

Effeciency of drives, ξdr = 91.58% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

=91580

1979

.

.

= 86.47kW

Yearly cost = 90.036524228.0

47.86 ××××yr

day

day

hr

kWhkW

= RM 155434

10. Pump 3(P102)

Power (shaft) = 22.85kW

Effeciency of drives, ξdr = 86.93% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

= 86930

8522

.

.

= 26.29kW

Yearly cost = 90.036524228.0

29.26 ××××yr

day

day

hr

kWhkW

= RM 47258

11. Pump 4(P103)

Power (shaft) = 685.64kW

Effeciency of drives, ξdr = 95.37% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

= 9537.0

64.685

= 718.93kW

71

Page 332: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Yearly cost =

90.036524228.0

93.718 ××××yr

day

day

hr

kWhkW

= RM 1292314

12. Pump 5(P104)

Power (shaft) = 322.75kW

Effeciency of drives, ξdr = 93.67% (refer to table 3.7) Appendix

Electric Power, Pr =dr

outputPower

ξ

= 93670

75322

.

.

= 344.56kW

Yearly cost =

90.036524228.0

56.344 ××××yr

day

day

hr

kWhkW

= RM 619366

Total cost of utilities (CUT) = RM 6779190

4.2.2.3Cost of Raw Material (CRM)

1. Isobutane = 39353 kg/h

Price RM 0.8094/kg

= 90.08094.03652439353 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 251123677/yr

2. Methanol = 15462 kg/hr

Price RM 0.988/kg (Chemical week, June 2003)

= 90.0988.03652415462 ××××

kg

RM

year

day

day

hr

hr

kg

= RM 120439579/yr

72

Page 333: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

3. Catalyst (Alumina silica) = kg

tonne

tonne

RMkg

1000

15.995679 ××

= RM909

Total cost of raw material = RM 251123677/yr + RM 120439579/yr

= RM 371563256/yr

Total cost of catalyst (for 3 year) = RM 909

Total cost = RM 371564165

The estimation of total manufacturing cost (with catalyst):

COM = 0.304FCI + 2.73COL + 1.23(CUT + CWT + CRM)

COM = 0.304 (31292629) + 2.73 (900000) + 1.23 (6779190 + 371564165)

COM = RM 477332286/yr

The estimation of total manufacturing cost (without catalyst):

COM = 0.304FCI + 2.73COL + 1.23(CUT + CWT + CRM)

COM = 0.304 (31292629) + 2.73 (900000) + 1.23 (6779190 + 371563256)

COM = RM 477331168/yr

73

Page 334: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.2: Estimation Cost Of Purchased Equipment

Equipment Capacity/Size Material Of Construction

Operating Pressure

FP FM FBM Cp CBM Co BM

C100 W=137.73kW Carbon Steel

0.0 barg 2.2 16000 264000

C101 W = 22.85kW Carbon Steel

0.1 barg 3.0 3536676 10610028

E 100Heat Exchanger

Area =94.33m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1500015000

48000

E 101Heat exchanger

Area =95.71m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1600016000

51200

E 102Heat Exchanger

Area =94.33m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1500015000

48000

E 103Heat Exchanger

Area =94.33m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1500015000

48000

E 104Heat Exchanger

Area =94.33m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1500015000

48000

E 105Heat Exchanger

Area =94.33m2

(floating head)Tube-CSShell-CS

Tube- 9 bargShell- 9 barg

1.01.0

1.01.0

3.23.2

1500015000

48000

74

Page 335: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.2: Estimation Cost Of Purchased Equipment

Equipment Capacity/Size Material Of Construction

Operating Pressure

FP FM FBM Cp CBM Co BM

P100 W = 327.94kW Cass Steel 3.5 barg 1.01.0

1.81.0

4.5183.31

36881244152

333257

P101 W = 79.19kW Cass Steel 0.1 barg 1.01.0

1.81.0

4.5183.31

857156740

77448

P102 W = 22.85kW Cass Steel 0.0 barg 1.01.0

1.81.0

4.5183.31

14299460

12912

P103 W = 685.64kW Cass Steel 1.50 barg 1.01.0

1.81.0

4.5183.31

52276346067

472366

P104 W = 322.75kW Cass Steel 0.0 barg 1.01.0

1.81.0

4.5183.31

36593121123

330654

R100 D = 6.512 H = 18m

Stainless Steel 1.75 barg 1.31.0

4.01.0

11.54.2

200000230000

840000

R101 D = 1.814mH = 4m

Carbon Steel 1.0 barg 1.01.0

1.01.0

4.24.2

1900079800

79800

T100

Sieve tray

D = 0.765 mH = 10.8511 trays

StainlessSteel

3.5 barg 1.21.0

4.01.0

1142.01.0

40000

294160000

5821

440000

9702

T101 D = 1.01 mH =9 m

StainlessSteel

1.75 barg 1.21.0

4.01.0

2.01.2

1700068000

178000

T102

Sieve tray

D = 0.765 mH = 10.8511 trays

StainlessSteel

3.5 barg 1.21.0

4.01.0

1142.01.0

40000

294160000

5821

440000

9702

V100 Stainless Steel 7131Total 12659343 3223841

75

Page 336: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.3 PROFITABILITY ANALYSIS

Profitability is used as the general term for the measure of the amount of profit

that can be obtained from a given situation. Profitability therefore, is the common

denominator for all business activities.

The feasibility of MTBE production in Malaysia is evaluated by profitability analysis.

The profitability of the project will be the largest factor that makes a project

economically attractive. To this stage, almost all the design and cost information

required for the profitability analysis were obtained. Based on the information

available, the best methods assessing the profitability of alternatives are based on

projections of the cash flows during the project file.

A proposed capital investment / project and its associated expenditures can be

recovered by revenue (or savings) over time in addition to a return on the capital that is

sufficiently attractive in view of the risks involved of the potential alternatives uses.

There are 5 common methods in performing engineering economic analysis:

1) Present Worth (PW)

2) Future Worth (FW)

3) Annual Worth (AW)

4) Internal Rate Of Return (IRR)

5) Benefits / Cost Ratio (B/C)

4.3.1 Discounted Cash Flow

The economic feasibility of this plant is evaluated using the Discounted Cash Flow

Analysis (DCF), which is the most frequently used method of economic evaluation in

the chemical industry. This method measures the profitability of the project taking into

account the time value of money. From this method, the internal rate of return (IRR) of

the project can be determined which indicates the feasibility of the project. The value of

IRR is calculated using the information obtained in the sections.

76

Page 337: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.3: Annual Cash Flow Before Tax

Year Gross Income (RM)

1

Annual Expenses (RM)

2

Investment & Salvage Value (RM)

3

Before Tax Cash Flow (RM)(4)= (1)+(2)+(3)

0 -19292629 -192926290 -964631 -9646310 -12000000 -120000001 493648959 -477332286 163166732 493648959 -477331168 163177913 493648959 -477331168 163177914 493648959 -477332286 163166735 493648959 -477331168 163177916 493648959 -477331168 163177917 493648959 -477332286 163166738 493648959 -477331168 163177919 493648959 -477331168 16317791

10 493648959 -477332286 1631667311 493648959 -477331168 1631779112 493648959 -477331168 1631779113 493648959 -477332286 1631667314 493648959 -477331168 1631779115 493648959 -477331168 1631779115 1929262.9 1929262.9

Estimated salvage value = 10%CFC (Coulson & Richardson, 1990)

= 0.1 x RM 19292629

= RM 1929262.9

77

Page 338: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 4.4 : Annual Cash Flow After Tax

Taxes rate at 38% is chosen referring to reference from MIDA

Year Gross Income (RM)

1

Expenses (RM)

2

Investment & Salvage Value (RM)

3

Depreciation Cost Basis * MACRS Rates

4

Taxable Income (RM)

(5)=(1)+(2)-(4)

Taxes (RM)Taxes rates = 38%

(6)=(5)*0.38

After Tax Cash Flow (RM)

(7)=(1)+(2)+(3)-(6)

Cumulative Cash Flow (RM)

0 -19292629 -192926290 -964631 -9646310 -12000000 -12000000 -322572601 493648959 -477332286 2756916.69 13559756.32 5152707.4 11163965.6 -21093294.42 493648959 -477331168 4724764.84 11593026.16 4405349.94 11912441.06 -9180853.343 493648959 -477331168 3374280.81 12943510.19 4918533.871 11399257.13 2218403.7894 493648959 -477332286 2409649.36 13907023.64 5284668.982 11032004.02 13250407.815 493648959 -477331168 1722831.77 14594959.23 5546084.508 10771706.49 24022114.36 493648959 -477331168 1720902.50 14596888.49 5546817.627 10770973.37 34793087.677 493648959 -477332286 1722831.77 14593841.23 5545659.668 10771013.33 455641018 493648959 -477331168 860451.25 15457339.75 5873789.104 10444001.9 56008102.99 493648959 -477331168 0 16317791 6200760.58 10117030.42 66125133.32

10 493648959 -477332286 0 16316673 6200335.74 10116337.26 76241470.5811 493648959 -477331168 0 16317791 6200760.58 10117030.42 8635850112 493648959 -477331168 0 16317791 6200760.58 10117030.42 96475531.4213 493648959 -477332286 0 16316673 6200335.74 10116337.26 106591868.714 493648959 -477331168 0 16317791 6200760.58 10117030.42 116708899.115 493648959 -477331168 0 16317791 6200760.58 10117030.42 126825929.515 1929262.9 1929262.9 733119.902 1929262.9 128755192.415 12964631 12964631 141719823.4

78

Page 339: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.3.2 Net Present Value

4.3.2.1 Present Worth

MARR is the rate set by an organization to designate the lowest level that makes an

investment acceptable. For a risky investment, MARR should be set higher.

However, for public purpose (government, public utility), MARR is lower. For this

proposed plant, MARR that has been selected is 15%.

By using present worth, we can determine either this proposed plant is

profitable and acceptable or not. Table 4.4 shows the value of present

worth by using 15%, therefore this proposed plant is profitable

because the value of PW is > 0.

PW when MARR = 15%

Table 4.5: Present Worth Value

Year After Tax Cash Flow (RM)

MARR = 15% Present Worth (PW), (RM)

0 -19292629 -192926290 -964631 -9646310 -12000000 -120000001 11163965.6 0.86957 9707849.572 11912441.06 0.75614 9007473.183 11399257.13 0.65752 7495239.554 11032004.02 0.57175 6307548.35 10771706.49 0.49718 5355477.036 10770973.37 0.43233 4656614.927 10771013.33 0.37594 4049254.758 10444001.9 0.3269 3414144.229 10117030.42 0.28426 2875867.07

10 10116337.26 0.24718 2500556.2411 10117030.42 0.21494 2174554.5212 10117030.42 0.18691 1890974.1613 10116337.26 0.16253 1644208.2914 10117030.42 0.14133 1429839.9115 10117030.42 0.12289 1243281.8715 13697750.9 0.12289 1683316.61PW 33178940.2

MARR = 15%

PW = RM 33178940.2

This project is attractive and acceptable because PW > 0

79

Page 340: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

4.3.3 Cumulative Cash Flow Diagram For The Evaluation Of A New Project

Table 4.6: After Tax Cumulative Cash Flow

Year After Tax Cash Flow (RM)

Cumulative CashFlow

0 -32257260 -322572601 11163965.6 -21093294.42 11912441.06 -9180853.343 11399257.13 2218403.7894 11032004.02 13250407.815 10771706.49 24022114.36 10770973.37 34793087.677 10771013.33 455641018 10444001.9 56008102.99 10117030.42 66125133.32

10 10116337.26 76241470.5811 10117030.42 8635850112 10117030.42 96475531.4213 10116337.26 106591868.714 10117030.42 116708899.115 10117030.42 126825929.515 13697750.9 140523680.4

Cumulative Cash Flow vs Year

-50000000-25000000

025000000

5000000075000000

100000000125000000

150000000

0 2 4 6 8 10 12 14 16

Year

Cumulative Cash Flow

(RM)

Figure 4.1: Cumulative Cash Flow (RM) Versus Year

4.3.4 Rate Of Return (ROR)

4.3.4.1 Internal Rate Of Return

80

Page 341: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

In theory, the Minimum Attractive Rate of Return (MARR) is chosen higher than the

rate expected from the bank or some safe investment that involved minimal

investment risk. The MARR for after taxes is selected at 15%. (Analysis, and

Design of Chemical Processes)

IRR is a method that produces an annual rate of profit, or return, resulting from an

investment and compared with the MARR. In determining the internal rate of return,

trial and error has been done based on the MARR that mentioned before. By trial

and error, the IRR for this plant has been found as 34.94%.

Table 4.7: Present Value (RM) when i = 30% and i = 40%

Year After Tax Cash Flow (RM)

i = 30% Present Value (RM)

i = 40% Present Value (RM)

0 -19292629 -19292629 -192926290 -964631 -964631 -9646310 -12000000 -12000000 -120000001 11163965.6 0.76923 8587657.26 0.71129 7940817.0922 11912441.06 0.59172 7048829.62 0.5102 6077727.4293 11399257.13 0.45517 5188599.87 0.36443 4154231.2754 11032004.02 0.35013 3862635.57 0.26031 2871740.9665 10771706.49 0.26933 2901143.71 0.18593 2002783.3886 10770973.37 0.20718 2231530.26 0.13281 1430492.9747 10771013.33 0.15937 1716576.39 0.09486 1021738.3258 10444001.9 0.12259 1280330.19 0.06776 707685.56859 10117030.42 0.0943 954035.969 0.0484 489664.2723

10 10116337.26 0.07254 733839.105 0.03457 349721.779111 10117030.42 0.0558 564530.297 0.02469 249789.481112 10117030.42 0.04292 434222.946 0.01764 178464.416613 10116337.26 0.03302 334041.456 0.0126 127465.849514 10117030.42 0.0254 256972.573 0.009 91053.2737815 10117030.42 0.01954 197686.774 0.00643 65052.505615 13697750.9 0.01954 267654.053 0.00643 88076.5383PW 4303026.05 -4410754.867

By interpolation, IRR value is 34.94% when P is at 0 value.

IRR (34.94%) > MARR (15%). This project is profitable and acceptable.

4.3.5 Sensitivity Analysis

A sensitivity analysis is a way of examining the effects of uncertainties in the

forecasts on the viability of a project.

AW = PW (A/P, 15%, 15)

81

Page 342: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 33178940.2 (0.17102)

= RM 5674262.32

FW = PW (F/P, 15%, 15)

= 33178940.2 (8.13706)

= RM 269979027.1

Table 4.8: Future Worth (RM) when MARR = 15%

Year After Tax Cash Flow (RM)

MARR = 15% Future Worth (FW), (RM)

0 -32257260 8.13706 -262479260.11 11163965.6 7.07571 78992983.042 11912441.06 6.15279 73294748.233 11399257.13 5.35025 60988875.454 11032004.02 4.65239 51325185.175 10771706.49 4.04556 43577584.926 10770973.37 3.51788 37890991.817 10771013.33 3.05902 32948745.28 10444001.9 2.66002 27781253.929 10117030.42 2.31306 23401298.38

10 10116337.26 2.01136 20347596.1111 10117030.42 1.74901 17694787.3712 10117030.42 1.52088 15386789.2313 10116337.26 1.3225 13378856.0314 10117030.42 1.15 11634584.9815 10117030.42 - 10117030.4215 13697750.9 - 13697750.9

FW 269979801.1

4.3.6 Payback Period

The payback period analysis is a more simplistic method of calculating the

economic feasibility of a project. This method determines the period in number of

years required for the project to recover back the initial capital investment of the

plant. In using this method, the assumptions stated above such as below still

applies:

1) The plant life is taken as 15 years.

2) The annual net profit of the plant is taken as constant.

3) The class life or recovery period is 7 years.

4) The working capital is taken as 5% of the total fixed capital cost.

4.3.6.1 Simple Payback Period

Table 4.9 : Simple Payback Period

82

Page 343: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Year After Tax Cash Flow Cumulative Cash Flow0 -32257260 -322572601 16316673 -159405872 16317791 377204

By interpolation,

Table 4.10 : The Interpolation Simple Payback Period

Cumulative Cash Flow

Year

-15940587 10 1.97377204 2

Therefore, MTBE plant can have payback period with:

Payback period = (1 + 0.97) years = 1 years 12 month ≈ 2 years

4.3.6.2 Discounted Payback Period

Normally, the interest in Malaysia standardized for chemical plant. By referring to Hong Leong Bank, the interest is 15% and use as a basis for discounted payback period.

Table 4.11 : Discounted Payback Period

Year Annual Cash Flow After Tax

Cumulative Cash Flow

Cumulative Cash Flow After Tax

0 -32257260 -322572601 16316673 -15940587 -18331675.052 16317791 -2013884.05 -2315966.6583 16317791 14001824.34 16102097.99

By interpolation,

Table 4.12 : The Interpolation Discounted Payback Period

Cumulative Cash Flow

Year

-2315966.658 20 2.0316102097.99 3

Therefore, MTBE plant can have payback period with:

= 2 + (0.03) years

83

Page 344: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

= 2 year 1 month

4.4 CONCLUSION

Based on this chapter, the economic evaluation of MTBE plant are made

through study in all aspect including feasibility study, process synthesis and flow

sheeting and designed of major equipment.

From the cash flow analysis, the payback period for the MTBE plant is about 2

years. Furthermore, it should be stated that the present work is primarily illustrated

based on the method of engineering economic analysis of chemical processes.

PW is positive value so the project is attractive and acceptable same as when IRR

is bigger than MARR.

By estimate the value of PW, FW and AW by using relationship between PW and

FW the answer of FW same with estimate direct from CFAT.

REFERENCES

84

Page 345: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Perry R.H and Green, Don, “Perry’s Chemical Engineer’s Handbook”, 7th

Edition, McGraw-Hill Book Company, Singapore, 1984.

Sinnott, R. K., Coulson & Richardson, “Chemical Engineering Volume 6,

Chemical Engineering Design”, Butterworth Heinemann, 1999.

Peters, max Stone, “Plant Design and Economics for Chemical

Engineers”, 2nd Edition, McGraw-Hill Chemical Engineering Series, 1968.

85

Page 346: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 5

PROCESS INTEGRATION AND PINCH TECHNOLOGY

5.1 INTRODUCTION

Process integration can lead to a substantial reduction in the energy requirements

of a process. One of the most successful and generally useful techniques is that

developed by Bodo Linnhoff and other workers: pinch technology. The term derives

from the fact that in a plot of the system temperatures versus the heat transferred, a

pinch usually occurs between the hot stream and cold stream curves. It has been

shown that the pinch represents a distinct thermodynamic break in the system and

that, for minimum energy requirements, heat should not be transferred across the

pinch, Linhoff and Townsend (1982) (Ref: Coulson & Richardson’s vol. 6)

5.2 PINCH TECHNOLOGY

There are four streams to consider the problem of integrating the utilization of

energy. Two hot streams which require cooling and two cold streams that have to

be heated. Each streams starts from a source temperature Ts, and is to be heated

or cooled to a target temperature, Tt. The heat capacity of each stream is shown as

CP.

CP is given by:

CP = mCp

(5.1)

Where, m = mass flow rate, kg/s

Cp = average specific heat capacity between Ts and Tt,

(KJ/kgoC)

Table 5.1: Shows the process data for each stream.

86

Page 347: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Stream number Type Heat capacity Ts(oC) Tt (oC)

Heat

LoadCp(KW/ oC) (KW)

1 HOT 3.2 180 50 4162 HOT 1.3 150 30 1563 COLD 2 20 140 2404 COLD 4 75 135 240

The heat load shown in the table is the total heat required to heat or cools the

stream from the source to target temperature. The stream are shown

diagrammatically below,

Stream 1 180°C CP = 3.2 kW/°C 50°C

Stream 2 150°C CP = 1.3kW/°C 30°C

Stream 3 20°C CP = 2 kW/°C 140°C

Stream 4 75°C CP = 4 kW/°C 135°C

Figure 5.1: Diagrammatically representation of process stream

5.3 THE PROBLEM TABLE METHOD

The problem table is a numerical method for determining the pinch temperature and

the minimum utility requirements. Firstly, it needs to convert the actual stream

temperature Tact into the interval temperatures Tint.

Hot streams Tint = Tact – (ΔTmin/2)

Cold streams Tint = Tact – (ΔTmin/2)

The minimum temperature difference taken from composite curve as, ΔTmin = 10 oC

87

Page 348: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Hot a nd Cold Com posite curves

0

50

100

150

200

250

300

350

1 2 3 4

Enthalpy,102 kW

Tem

pera

ture

oC

Hot Stream s

Cold Stream s

Figure 5.2: Hot and cold streams composite curves

Table 5.2: Interval Temperature for ΔTmin = 10oC

Stream Actual Temp. oC Interval Temp. oC

1 180 50 175 45

3 150 30 145 25

9 20 140 25 145

10 75 135 80 140

The heat balance for the streams falling within each temperature interval:

For the nth interval:

ΔHn = (∑CPc - ∑CPh) (ΔTn)

(5.2)

Where, ΔHn = net heat required in the nth interval

∑CPc = sum of the heat capacities of all the cold streams in interval

∑CPh = sum of the heat capacities of all the hot streams in the

interval

ΔTn = interval temperature difference=(Tn-1-Tn)

88

Page 349: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

175

Interval 1: 145

1 4

Interval 2: 140

2 3

Interval 3: 80

Interval 4: 45

Interval 5: 25

Figure 5.3: Intervals and streams

Table 5.3: Ranked order of interval temperature

Rank,oC Interval, ΔTn oC Stream in interval

175

145 30 -1

140 5 4-(2+1)

80 60 (3+4)-(1+2)

45 35 3-(1+2)

25 20 (3-2)

Cascading the heat from one interval to the next implies that the temperature

difference is such that the heat can be transferred between the hot and cold

streams. A negative value in the column indicates the temperature gradient is in the

wrong direction and that the exchange is not thermodynamically possible.

Table 5.4: Problem Table

Interval Tint,oC ΔTno,C

∑CPc - ∑CPh

(Kw/oC) ΔHn (KW) surplus/deficit

89

Page 350: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

175

1 145 30 -3.2 -96 S

2 140 5 0.5 2.5 D

3 80 60 2.1 126 D

4 45 35 -2.0 -87.5 S

5 25 20 1.0 14 D

Interval temperature

Rank oC

175oC 0kW 32.5 kW

145oC -96kW 96 kW -96 kW 128.5 kW

140oC 2.5 kW 93.5 kW 2.5 kW 126 kW

80oC 126 kW -32.5 kW 126 kW 0 kW

45oC -87.5 kW 55 kW -87.5 kW 87.5 kW

25oC 14 kW -41 kW 14 kW 73.5 kW

Figure 5.4 Heat Cascade

From figure 5.4: pinch occurs at interval temperature 80oC

At the pinch, hot stream = 80 + 5

(5.3)

= 85 oC

Cold stream = 80 – 5

(5.4)

= 75oC

5.4 THE HEAT EXCHANGER NETWORK

The grid representation of the stream is shown in Figure 5

CP

90

Page 351: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

(KW/ oC) 85oC75oC

180oC 50 oC3.2

150 oC 30 oC1.3

140 oC 20 oC2.0

135 oC 75 oC4.0

Figure 5.5 Grid for 4 stream problem

For maximum energy recovery (minimum utility consumption) the best performance

is obtained if no cooling is used above the pinch. This means the hot streams

above the pinch should be brought it the pinch temperature solely by exchange with

the cold streams.

THE NETWORK DESIGN ABOVE THE PINCH

CP hot ≤ CP cold

Applying this condition at the pinch, stream 1 can be matched with stream 4, but not

with 3.

Matching streams 1 and 4 and transferring the full amount of heat required to bring

stream 1 to the pinch temperature gives;

ΔHex = CP (T pinch - Ts)

(5.5)

= 304 kW

This will also satisfy the heat load required to bring stream 4 to its target

temperature.

91

2

1

3

4

Page 352: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Stream 2 can be matched with stream 3, whilst satisfying the heat capacity

restriction. Transferring the full amount to bring stream 3 to the pinch temperature:

ΔHex = CP (T pinch- Ts)

= 97.5 kW

The heat required to bring stream 3 to its target temperature, from the pinch

temperature, is:

ΔH = 2.0(140-75)

= 130 kW

So a heater will have to be included to provide the remaining heat load:

ΔHhot = 130-97.5 kW

(5.6)

= 32.5 kW

THE NETWORK DESIGN BELOW THE PINCH

Stream 1 is matched with stream 3 transferring the full amount to bring stream 1 to

its target temperature; transferring:

ΔHex = 3.2(85-50)

= 112 kW

Stream 3 requires more heat to bring it to pinch temperature; amount needed:

ΔH = 2.0(75-20)-85kW

= 25 kW

So transferring 25 kW will raise the temperature from the source temperature to:

20+ 25/2 =32.5 kW

and gives a stream temperature difference on the outlet side of the exchanger of:

85-32.5 = 52.5 kW

So the minimum temperature difference condition, 10oC will not be violet by this

match.

Stream 2 will need further cooling to bring its to its target temperature, so a cooler

must be included; cooling required.

ΔHcold = 1.3 (85-50)-25

= 73.5 kW

92

Page 353: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The proposed network for maximum energy recovery is shown in Figure 5.5

Figure 5.6 Proposed heat exchanger network

5.5 MINIMUM NUMBER OF EXCHANGERS

The network shown in figure 5.5 was designed to give the maximum heat recovery,

and therefore give the minimum consumption, and cost of the hot and cold utilities.

In figure 5.5 it is clear that there is scope for reducing the number of exchangers.

Exchanger D can be deleted and the heat loads of the cooler and heater increased

to bring stream 2 and 3 to their target temperatures. Heat would across the pinch

and the consumption of the utilities would be increased

For complex networks a more general expression is needed to determine the

number of exchangers:

Zmin = N’ +L’ – S (5.7)

Where L’= the number of internal loops present in the network

S= the number of independence branches (subsets) that exist in the

network

N= the number of streams including the utilities

B C

A D

A

B C

D

1

2

3

4

93

Page 354: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

In a final design, there are 3 exchangers, rather than 4 before the process

integration and pinch technology, with the minimum heating and cooling loads, 32.5

kW and 73.5 kW, respectively, match those predicted from the problem table,

compare with the loads for heating and cooling before process integration: 416 kW

and 240 kW.

94

Page 355: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

CHAPTER 6

WASTE TREATMENT

6.1 INTRODUCTION

Pollution is something that should be taken into serious consideration in any

petrochemical plant especially the MTBE plant. Pollution, no matter what kind of the

pollution is has serious negative effects not only to human beings, but also to

animals, plants and to the environment. Therefore, it is the responsibility of each

individual to ensure that their activities are not harmful to the environment. This

includes activities and works involved in designing a plant. Waste from any

petrochemical plant should be treated according to the local and international

standards before being released to the environment.

In the MTBE plant, the wastes are only the in liquid form and gas form. The liquid

will be treated in the wastewater treatment plant. The hydrogen gas leaving the

reactor is sent to a gas cylinder which it is then sold to interested company at

market price. The treatment processes and systems employed by the MTBE plant

is the typical processes and systems based on Howard S. Peavy, Donald R. Rowe,

George Tchobanoglous; Environmental Engineering, McGraw-Hill, 1985 and

David H. F. Liu, Bela G. Liptak, Wastewater Treatment, Lewis Publishers, 1999.

6.2 WASTEWATER TREATMENT

95

Page 356: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Wastewater treatment is a must in any plant. The wastewater from plant

cannot be channeled into the sewage system without being treated. The

wastewater from the MTBE plant may contains a small amount of the feed and

product and a small quantity of by-products such as butene, TBA and dimethyl-

ether. According to the site location selected, the wastewater from the plant is to be

treated and should comply with Standard B which is shown Table 6.1.

In the design of the wastewater treatment plant for the production of MTBE,

the COD value used is based of the COD value of wastewater from other plants

that are in operation. The COD value of 3000 mg/l will be used for design purposes.

The design of the plant consists of preliminary, primary and secondary treatment

where each treatment unit chosen is based on the characteristics of the influent to

be treated. Before being treated, all the wastewater is channeled to the holding

tank. It is then ferried for screening and the next process is the primary settling

tank. The effluent leaving this tank is sent to the active sludge reactor. After that, it

will be sent to the secondary settling tank. Finally, the effluent undergoes

adsorption by activated carbon before leaving the wastewater treatment plant.

6.2.1 Denitrification Process (Chemical Treatment)

96

Page 357: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

To remove methanol in the waste water, we use the denitrification process

in our plant waste treatment. In the denitrification process, nitrate is reduced to

nitrogen gas by the same facultative, heterotrophic bacteria involved in the

oxidization of carbonaceous material. For reduction to occur the dissolved oxygen

level must be at or near zero and a carbon supply must be available to the bacteria.

Because low carbon content is required for the previous nitrification step, carbon

must be added before denitrification can proceed. A small amount of primary

effluent, bypassed around secondary and nitrification reactors, can be used to

supply the carbon. However, the unnitrified compounds in this water will be

unaffected by the denitrification process and will appear in the effluent. When

essentially complete nitrogen removal is required, an external source of carbon

containing no nitrogen will be required. The most commonly used external carbon

source is methanol, CH3OH. When methanol is added, the denitrification reaction is:

NO3- +

6

5CH3OH

2

1N2 +

6

5CO2+

6

7H2O +OH-

Theoretically, each milligram per liter of nitrate should require 1.9 mg/L of

methanol. Under treatment plant conditions, however about 3.0 mg/L of methanol is

required for each milligram per litre of nitrate, making this process an expensive

one.

97

Page 358: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Table 6.1 Parameter Limits for Wastewater and Effluent Under the Environmental

Quality Act 1974.

PARAMETER UNIT STANDARD A STANDARD BTemperature oC 40 40

pH - 6.0-9.0 5.5-9.0BOD5 at 20oC mg/l 20 50

COD mg/l 50 100Suspended solid mg/l 50 100

Mercury mg/l 0.005 0.05Cadmium mg/l 0.01 0.02

Chromium Hexavalent mg/l 0.05 0.05Arsenic mg/l 0.05 0.10Cyanide mg/l 0.05 0.10

Lead mg/l 0.10 0.5Copper mg/l 0.20 1.0

Manganese mg/l 0.20 1.0Nickel mg/l 0.20 1.0

Tin mg/l 0.20 1.0Zinc mg/l 1.0 1.0

Boron mg/l 1.0 4.0Iron mg/l 1.0 5.0

Phenol mg/l 0.001 1.0Free Chlorine mg/l 1.0 2.0

Sulfide mg/l 0.5 0.5Oil and grease mg/l None 10

* Both standards could be used and acceptable, but only one is chosen, Standard B

for the wastewater treatment for the MTBE plant.

6.3 WASTEWATER TREATMENT PLANT DESIGN

The design of the wastewater treatment plant consists of the holding tank, the

design of the screening device, then the design of the settling tank, the design of

the primary and secondary sedimentation tanks, and lastly the design for the

activated sludge process.

98

Page 359: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The next step is the sludge treatment which consists of the sludge

thickening by centrifugation, condensation by using heat treatment and lastly

dehydration by using vacuum filter.

Since the gas produced only hydrogen and no other gases, so the gas

needs no treatment. The hydrogen gas produced is stored to be sold to interested

companies like MOX Sdn. Bhd..

6.3.1 Design of Holding Tank

The purpose of the holding tank is to hold and accumulate the wastewater

before it undergoes further treatment. The design of the holding tank is as follows:

Wastewater flow rate =day

hr24

hr

m5642.1

3

×

=day

m54.37

3

Volume of wastewater per day = 37.54 m3

By taking into consideration the depth of the holding tank as 3 m, and the ratio of

the length to the width as 3:1, the dimensions of the holding tank are as follows:

Depth of holding tank = 3.0 m

Width of holding tank = 3.0 m

Length of holding tank = 9.0 m

Volume of holding tank = 81.0 m3

This means that the holding time is about two days (81m3/37.54m3) and it is

acceptable.

6.3.2 Design of Screening Device

In the preliminary treatment of the wastewater, the treatment chosen is by

using screening. Fine screens made of woven-wire cloth are used. The screen is

used to remove small particles which might be in the wastewater. A screen with

small sized openings is chosen because the wastewater does not contain large

particles. The head loss is calculated by using the following equation:

99

Page 360: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

( )2

2

1

=A

Q

gChL (6.1)

Where hL = head loss, m

C = waste constant for screen

= 0.6 for clean screen (Metcalf & Eddy, 1979)

g = gravity, ms-2

Q = Flow through screen, m3s-1

A = Effective opening area for submerged screen, m2

= take as 9m2

Thus,2

910x345.4 4

81.926.0

1h L

××=

m109799.1h 10L

−×=

6.3.3 Design of Settling Tank

For the wastewater treatment, sulfide precipitation treatment is used to

remove heavy metals from the wastewater. The precipitant used is sodium sulfide,

which will react with the metal ions and will form non-soluble sulfide metal.

However, extra care is required in this process to avoid sulfide poisoning. Pre-

treatment which involves the increasing of the pH of the wastewater is required to

minimize the release of hydrogen sulfide gas. The design of the settling tank is as

follows:

Take holding time = 15 minutes (standard holding time)

Average flow rate =hr

m5642.1

3

Holding time = 15 minutes

= 0.25 hr

Tank volume = Average flow rate × Holding time

= hr25.0hr

m5642.1

3

×

= 3m391.0

100

Page 361: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

By taking the depth as L=0.8m, and using a square tank,

Length of tank =L

V

=8.0

391.0

= 0.70 m

6.3.4 Design of Primary and Secondary Sedimentation Tank

Primary sedimentation is a unit operation designed to concentrate and

remove suspended organic solids from the wastewater. The secondary

sedimentation tank is designed as a unit operation for the activated sludge process.

The design for the sedimentation tanks are as follows:

Take holding time = 2 hr

Average flow rate =hr

m5642.1

3

Holding time = 2 hr

Tank Volume = Average flow rate × Holding time

= hr2hr

m5642.1

3

×

= 3m1284.3

By taking the depth as L=2m,

Length of tank =L

V×2

=2

1284.32×

= 2.50 m

6.3.5 Design for Activated Sludge Process

The activated sludge process is a treatment process that involves the production of

a living or active microorganism which is used to stabilize the waste aerobically. A

completely mixed reactor is used in this process. This reactor is used as it is

suitable for general wastewater treatment and it has a high efficiency (85-95%) to

reduce high COD or BOD. This process involves a completely mixed reactor

followed by a secondary sedimentation tank. Part of the sludge from the secondary

101

Page 362: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

sedimentation tank is recycled to the influent reactor. The design for the reactor is

as follows:

Average flow rate =hr

m5642.1

3

Holding time = 3 hr

Tank Volume = Average flow rate × Holding time

= hr3hr

m5642.1

3

×

= 3m693.4

By taking the depth as L=2m,

Length of tank =L

V

=2

69.4

= 1.53 m

6.3.6 Oxygen Demand and Aerator

COD (kg/day) = Influent COD × wastewater flow rate

=day

m54.37

m

kg3

3

=day

kg62.112

By assuming that 1kg COD requires 1kg of oxygen, thus 112.62 kg/day COD

requires 112.62 kg O2/day. The aerator used is a mechanical aerator with an

oxygen transfer rate of 1.8 kg O2/day.

Power needed = O2 needed per hour / O2 transfer rate

Oxygen needed per hour =hr24

day1

day

kg62.112 ×

=hr

kg69.4

102

Page 363: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Thus, power needed =

kg

day

hr

kg

8.1

69.4

= 2.61 kW

An aerator unit provides 10kW of power. Thus, one unit is sufficient to provide

enough power for the activated sludge process.

6.4 SLUDGE TREATMENT

In this wastewater treatment plant, sludge is formed in the primary and

secondary sedimentation tank. This sludge needs to be treated and disposed. For

the MTBE plant, the following operations are used for the sludge treatment system:

i. Sludge thickening by centrifugation

ii. Condensation by using heat treatment

iii. Dehydration by using vacuum filter

Wastes from the sludge treatment system, for example the filtrate from the

vacuum filter, are sent to the influent treatment plant to undergo further treatment.

Dehydrated sludge is sent to the sludge dump site. The flow chart for the sludge

treatment is shown in Figure 6.1. Although the treatment is expensive, it is

necessary for our plant.

103

Page 364: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

C EN TR IFU G ATIO NTH IC KEN IN G

SL U D G ESTO R AG E

H EA TTR E ATMEN T

VAC U U MFIL TER

S l udge P la nt

S l udge to d is pos al s i te

T o in flu ent p lan t

D ehy dra ted s lud ge

F i l tra te to in fluen t p l an t

Figure 6.1 The Sludge Treatment System

6.5 WASTE TREATMENT PLANT LAYOUT

Generally, the layout of a waste treatment plant depends on the process

requirements. The treatment plant covers an area of 800m2. The plant layout is

shown in Figure 6.3. The waste treatment plant consists of the following units:

1. 1 holding tank

2. 1 primary sedimentation tank

3. 1 secondary sedimentation tank

4. 1 activated sludge reactor

5. 1 screening device

6. 1 power house

7. 4 pumps

8. 1 sludge store

9. Units in the sludge treatment process

Table 6.2 Functions of Pumps in the Waste Treatment Plant

Pump Function

104

Page 365: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

1 To pump sludge from the sedimentation tank to the sludge

treatment tank.

2 To pump sludge from the secondary sedimentation tank to be

recycled to the activated sludge reactor.

3 To pump sludge from the secondary sedimentation tank to the

sludge treatment process.

4 To pump wastewater from the sludge treatment system to be

recycled to the influent plant.

P R IM A R Y S E D IM E N T A T IO N T A N K

S E T T L IN G T A N K

S E C O N D A R Y S E D IM E N T A T IO N T A N K

A E R A T IO N T A N K

P O W E R H O U S E

1

2 3

S L U D G E T R E A T M E N T P R O C E S S

H O L D IN G T A N K

S C R E E N IN G D E V IC E

4

U

L E G E N D

P u m p

3

4

2

1

S lu d g e f ro m p r im a ry s e d im e n t a t io n t a n k to b e t re a t e d

S lu d g e f ro m s e c o n d a r y s e d im e n t a t io n t a n k to b e r e c y c le d

S lu d g e f ro m s e c o n d a r y s e d im e n t a t io n t a n k to b e t r e a te d

W a s t e w a te r f r o m s lu d g e t r e a tm e n t s y s te m to in f lu e n t p la n t

F lo wS lu d g e F lo w

W a s t e w a t e r F lo w

Figure 6.2 Waste Treatment Plant Layout

6.6 ABSORPTION TANK USING GRANULAR ACTIVATED CARBON

105

Page 366: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

In the operation of absorption tank, granular activated carbon (GAC) is used

which has a diameter between 0.1-2.0 mm. The contact system for GAC consists of

cylindrical tanks, which contain a bed of the carbon material (refer the design

given). The water is passed through the bed with sufficient residence time allowed

for completion of the adsorption process. The system is operating in a fixed bed

mode. Fixed bed systems are batch operations that are taken off the line when the

adsorptive capacity of the carbon in used up.

Although fixed granular carbon beds can be cleaned in a place with

superheated steam, the most common practice is to remove the carbon for cleaning

in a furnace. The regeneration process is essentially the same as the original

activation process. The adsorbed organics are first burned at about 800 oC in the

absence of oxygen. An oxidizing agent, usually stream, is then applied at slightly

higher temperatures to remove the residue and reactivated carbon.

6.6.1 Analysis of the Absorption Process

The adsorption process takes place in the three steps, macrotransport,

microtransport and sorption. The quantities of adsorbate that can be taken up by an

adsorbent are function of both the characteristics and concentration of adsorbate

and the temperature. Generally, the amount of material absorbed is determined as

a function of the concentration at a constant temperature and the resulting function

is called an absorption isotherm. Equation that are often used to described the

experimental isotherm data where developed by Freundlich by Langmuir and by

Brunauer, Emmet and Teller (BET isotherm).

Freundlich Isotherm Equation:

nefCK

m

x 1=

Where x/m = amount adsorbate absorbed per unit weight of absorbent (activated carbon)

eC = equilibrium concentration of absorbed in solution after absorption nK f , = empirical constant

106

Page 367: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

The constants in the Freundlich isotherm can be determined by plotting (x/m)

versus C and making use of above equation rewritten as:

ef Cn

Km

xlog

1loglog +=

6.6.2 Breakthrough Absorption Capacity

In the field, the breakthrough adsorption capacity, ( )bmx , of the GAC in a

full-scale column is some percentage of the theoretical absorption capacity found

from the isotherm. The ( )bmx of a single column can be assumed to be

approximately 25 to 50 percent of the theoretical capacity ( )omx . Once ( )bmx is

known, time to breakthrough can be calculated by solving the following equation for

bt

( )[ ]LmgMgallbM

tCCQ

M

X

m

x

c

bbi

c

b

b

.34.82

−==

Where bm

x

= field breakthrough adsorption capacity, lb/lb or g/g

bX = mass of organic material absorbed in the GAC column at breakthrough, lb or g

cM = mass of carbon in the column, lb or g

Q = flow rate, Mgal/d

iC = influent organic concentration, mg/L

bC = breakthrough organic concentration, mg/L

bt = time to breakthrough, day

Equation above was developed assuming that Ci is constant and that the effluent

concentration increases linearly with time from 0 to Cb value. The time breakthrough

can be calculated using the rearranging equation above. From the test data by

Freundlich adsorption isotherm plotted,

107

Page 368: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

m

x = 0.0015 56.3

eC

0

m

x= 0.0015(3.250)3.56

= 0.0996 mg/mg say 0.10 mg/mg = 0.10 Ib/Ib

Determination of breakthrough time,

[ ])/.(/34.82/(

)/(

LmgMgalIbCCQ

Mmxt

bi

cbb −

=

Following condition apply:

( )bmx =50 percent of ( )omx =o.5 (0.10 lb/lb) = 0.050 lb/lb

Assuming from the data testing by Freundlich adsorption isotherm,Surface area = 210 ft = 0.929m2

( ) ( )

Lmg0.75

Lmg3.2

072.07200010min1440min.0.5

900,1380.51022

32

==

==××=

=××=

b

i

c

C

C

dMgaldgalftdftgalQ

lbftlbftftM

the time to breakthrough is

[ ])/.(/34.82/(

)/(

LmgMgalIbCCQ

Mmxt

bi

cbb −

=

day 56=bt

Therefore, results from our study based on Freundlich adsorption isotherm the

activated carbon in our design waste treatment column vessel can long lasting for

56 day. Therefore, our estimation is changing the activated carbon in the vessel

waste treatment in every 56 day to make sure the efficiency capacity of adsorption

carbon is in the maximum capacity.

REFERENCES

108

Page 369: 38997683 Methyl Tertiary Butyl Ether MTBE Full Report

PRODUCTION OF 300,000 METRIC TON OF MTBE PER YEAR

Howard S. Peavy, Donald R. Rowe, George Tchobanoglous; Environmental

Engineering, McGraw-Hill, 1985.

David H. F. Liu, Bela G. Liptak, Wastewater Treatment, Lewis Publishers, 1999.

109