Chapter 6 Update (1)

CHAPTER 6

ENERGY BALANCE

6.1INTRODUCTION

The energy balance is based on the temperature of the each equipment. Heat capacity of each component is specified base on the heat capacity of each component which is 2-butanol, methyl ethyl ketone and hydrogen. In calculation of energy balance it can be seperated by 2 phase which are liquid and gas phase.

After doing manual calculation for mass balance, energy consumption is calculated and the mole flow rate is used based the manual calculation from mass balance. As our reference state where H = 0, we consider Po = 1 atm, To = 298 K and elemental species. Beside that there is no enthalpy for pressure change of ideal gas.

6.2HEAT OF VAPORIZATION

Heat of vaporization is the the amount of heat require to change the phase from liquid to gas. This heat of vaporization can be calculated from chemical properties hadbook :

1b=

Table 6.1 Heat of vaporization for each component

Component

A

n

2 butanol

75.278

536.01

0.512

MEK

50.652

535.50

0.450

Hydrogen

0.659

33.18

0.380

6.3HEAT CAPACITY

Heat capacity is the amount of heat require to change the temperature by 1C.The heat capacity of liquid and gas can be calculate by using formula:

= (liquid)

= + ET4(gases)

Table 6.2 Heat capacity of gas for each component

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

MEK

61.406

7.532X10-1

- 2.3814X10-3

3.2240X10-6

Hydrogen

50.607

-6.1136

3.0930X10-1

- 4.1480X10-3

Table 6.3 Heat capacity of gas for each component

Compound

A

B

C

D

E

2-Butanol

22.465

3.5134x10-1

- 1.2858x10-4

1.193X10-8

1.294X10-11

MEK

37.369

2.3045X10-1

5.7387x10-6

-8.6168X10-8

2.9637X10-11

Hydrogen

25.399

2.0178X10-2

-3.8549x10-5

3.1880X10-8

-8.7585X10-12

6.4ENTHALPHY OF FORMATION OF GAS

Entalphy of formation of gas is the che nage of entalphy from the formation of 1 mole of the compound from its constituent elemnt

Table 6.4 Entalphy of formation of gas for each component

Components

A

B

C

2- Butanol

-265.140

-1.0695x

5.1693x

Methyl Ethyl Ketone

-216.593

-8.4826x

3.9084x

Hydrogen

-

-

-

6.5ENERGY BALANCE CALCULATION

The total energy for each equipment are calculated manually. Then the energy compared with the total energy from Aspen hysys 8.0.

Assumption

Energy ideal property is used

All equipment in steady state

Temperature of 100kPa is used as atmospheric pressure

6.5.1Heat Exchanger E-101

(Liquid) (Liquid) (T = 110 oC = 383KP = 195 Kpa==+) (T= 25oC = 298 KP = 200 Kpa==+)

(Stream 2) (Stream 3)

=

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

Reference state ; Liquid, 25 oC, 1 atm(100kpa)

Stream 2

Component for 2-butanol

Change in pressure of liquid from 100kPa to 200kPa

1 =

1 = 9.0168

Stream 3

For 2-butanol

Change in temperature of liquid from 298K to 372.55K

1 = 1a+1b

1a =

1a =

1a =

Change in pressure of liquid from 100kPa to 195kPa

1b =

1b =

Change in temperature of liquid from 372.55K to 383K

1c =

1c =2007.6381

Total entalphy

1 =

1 =

Table 6.5 Entalphy inlet and outlet for 2-butanol

Species

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

181.8613

9.0168

1639.8070

181.8613

15472.1671

2813788.423

1639.8070

2813788.423


(T= 110oC = 383KP = 195 Kpa==+) (T = 500 oC = 773KP = 190 Kpa==+)Assumption: No entalphy for pressure change of ideal gases

(Liquid) (Gas)


=

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

MEK

61.406

7.532X10-1

- 2.3814X10-3

3.2240X10-6


Stream 4

For 2-butanol


1a =

1a =

1a =

Change in pressure from 100kPa to 195kPa

1b=100)kPa

1b=8.6514

Change in temperature of liquid from 372.55K to 383K

1c =

1c = 2007.6381

Total Entalphy

1 =13455.8776 + 8.6514 +2007.6381

1 =15472.1671

For MEK


2a =

2a =

Change in pressure from 1 atm to 1.95 atam

2b =

2b =

Change in temperature from 352.55K to 383K

2c =

2c =

Total entalphy

2 = 9032.7474 + 8.4678 + 5382.869

2 =14424.0842

Stream 5

For 2-butanol


1a =

1a =

1a =

Change in phase from liquid to gas at 372.55K

1b=

A

T

n

75.278

536.01

372.55

0.512

1b=

1b=

1b=40982.4801

Change in temprature of gas from 372.55K to773K

1c =

1c = 71690.0315

Total Entalphy

1 =13455.8776 + 40982.4801 +71690.0315

1 =

For MEK

Change in temperature of of liquid from 298K to 352.55K

2a =

2a =


1b=

A

T

n

50.652

535.50

352.55

0.450

1b=

1b=

1b=31239.5249

Change in temperature of gas from 352.55K to 773K

1b=

1b=65286.0477

Total entalphy

1=65286.0477 + 31239.5249 +

1 =

41

Component

(Table 6.6 Enthalpy component of the heat exchanger E-102)Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

124.7176

15472.1671

1929651.548

124.7176

126128.3892

16422408.04

MEK

1.2122

14424.0842

17484.8749

1.21220

127957.7955

1947136.423

16550365.84

-1882285.055

6.5.3 Heat Exchanger E-103

Assumption: No entalphy for pressure change of ideal gases

(Gas) (Gas) (T= 400oC = 673 KP = 185 Kpa==+) (T = 200 oC = 473KP = 180 Kpa==+)


= + ET4

Compound

A

B

C

D

E

2-Butanol

22.465

3.5134x10-1

- 1.2858x10-4

1.193X10-8

1.294X10-11

MEK

37.369

2.3045X10-1

5.7387x10-6

-8.6168X10-8

2.9637X10-11

Hydrogen

25.399

2.0178X10-2

-3.8549x10-5

3.1880X10-8

-8.7585X10-12

Reference state ; gas, 673K, 1.85 atm(185kpa)

Stream 6

For 2-butanol

Change in temperature from 663K to 473K

1a=

1a=-36061.0118

For MEK


1b=

1b=-31601.4079

For Hydrogen

1c=

1c=-5870.8451

Table 6.7 Enthalpy of component in heat exchanger E-103

Component

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

2.9068

0

0

6.2359

-36061.0118

-224872.9071

MEK

80.3947

0

0

119.6939

-31601.4079

-3782495.757

Hydrogen

0.0002

0

0

118.4871

-5870.8451

-695619.4104

0

-4702988.075


(Liquid) (Liquid) (T = 70 oC = 343 KP = 155 Kpa==+) (T= 0 oC = 273 KP = 160 Kpa==+)


=

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

MEK

61.406

7.532X10-1

- 2.3814X10-3

3.2240X10-6

Hydrogen

50.607

-6.1136

3.0930X10-1

- 4.1480X10-3


Stream 12

Component 2-butanol

1 = 1a+1b

Change in temperature from 25 oC to 0 oC

1a =

1a =

1a =


1b =

1b =

Total entalphy

1 =

1 =

Component Methyl Ethyl Ketone (MEK)

2 = 2a+2b


2a =

2a =

2a =


2b =

2b =

Total entalphy

2 =

2 =

Component Hydrogen

3 = 3a+3b


3a =

3a =

3a =

Change in presusre from 100kPa to 160kPa

3b =

3b =

Total entalphy

3 =

3=

Stream 19

For 2-butanol

1 = 1a+1b


1a =

1a =

1a =

Change in presurre from100kPa to 155kPA

1b =

1b =

Total entalphy

1 =

1 =


2 = 2a+2b


2a =

2a =

2a =


2b =

2b =

Total entalphy

2 =

2 =

FOr Hydrogen

3 = 3a+3b


3a =

3a =

3a =


3b =

3b =

Total entalphy

3 =

3=

Table 6.8 Enthalpy of component in heat exchanger E-106

Component

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

2.8676

-3934.55

-11282.7156

2.9068

7962.5938

23146.4412

MEK

78.2898

-3930.2019

-307694.7207

80.3947

7405.1457

598901.66

-318977.4363

622048.1012

6.5.5 Reactor R-101

(T=400 oC = 673KP = 185 kPa==+) (T=500 oC = 773KP = 190 kPa==+)


Components

A

B

C

2- Butanol

-265.140

-1.0695x

5.1693x

Methyl Ethyl Ketone

-216.593

-8.4826x

3.9084x

Hydrogen

-

-

-

Reference 1atm, 25C, gas

Stream 5

2-butanol

Heat of formation

Change in temperature of gas from 298K to 773K

1a=

1a=81043.0563

Total entalphy

1=-292420.5548 + 81043.0563

1=-211377.4985

Methyl Ethyl Ketone

Heat of formation


1b=

1b=71302.2356

Total entalphy

1=-273645.5945 + 71302.2356

1=-202352.3589

Stream 6

2-Butanol

Heat of formation


1a=

1a=60222.7058

Total Entalphy

1=-292420.5548 + 60222.7058

1=-232197.849

MEK

Heat of formation


1b=

1b=53057.6208

Total entalphy

Hydrogen

1c=

1c=10955.9027

Table 6.9 Enthalpy of component in reactor E-101

Component

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

124.7176

-211377.4985

-26362494.31

6.2359

-232197.849

-1447962.567

MEK

1.2122

-202352.3589

-245291.5295

119.6939

-179140.2282

-21441992.56

Hydrogen

-

-

-

118.4817

10955.9027

1298073.977

-26607785.84

-21591881.15

6.5.6 Heat exchanger E-101 and Separator V-101

Assumption

(Stream 9)No heat of vaporization of hydrogen since temperature since hydrogen already in gas state

(T = 70 oC =343 KGas phase)

(T = 200oC =343 KGas phase) (T = 70 oC =343 KLiquid phase)

(Stream 7)

(Stream 10)

Reference: 343 K, 1 atm, Liquid phase

Changing in temperature ;

=

=

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

MEK

61.406

7.532X10-1

- 2.3814X10-3

3.2240X10-6

Hydrogen

50.607

-6.1136

3.0930X10-1

- 4.1480X10-3

Changing in phase

Compound

A

T(K)

Tc

n

2-Butanol

75.278

343

536.01

0.512

MEK

50.562

343

535.50

0.450

Hydrogen

0.659

343

33.18

0.380

Stream 7

Component 2-butanol

Total entalphy


Heat of vaporization at 343K


Stream 9

Heat of formation

Component 2-butanol


Component of hydrogen

Assumption

Since the reference temperature is 70 C, there is no heat of vaporization of hydrogen

2720635.765-7274971.454

Species

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

6.2359

71298.1366

444608.05

2.8770

44621.9366

128377.3116

MEK

119.6939

57065.259

6830363.404

81.2460

31906.2902

2592258.454

Hydrogen

118.4817

0

0

118.4854

0

0

7274971.454

2720635.765

Table 6.10 Entalphy of component in heat exchanger E-101

6.5.7 Separator 2 (V-102)

Assumption

No heat of vaporization of hydrogen since temperature since hydrogen already in gas state

(T = 0oC = 273 KLiquid phase) (T = 0oC = 273 KGas phase) (T = 70oC = 343 KGas phase)

Reference: 273 K, 1 atm, Liquid phase

Changing in temperature ;

=

=

Compound

A

B

C

D

2-Butanol

95.037

5.6593X10-1

- 1.8256X10-3

2.6675X10-6

MEK

61.406

7.532X10-1

- 2.3814X10-3

3.2240X10-6

Hydrogen

50.607

-6.1136

3.0930X10-1

- 4.1480X10-3

Changing in phase ;

Compound

A

T(K)

Tc

n

2-Butanol

75.278

273

536.01

0.512

MEK

50.562

273

535.50

0.450

Hydrogen

0.659

273

33.18

0.380

For inlet of Separator

Heat of vaporization

Component 2-butanol

Therefore;


Heat of formation at 273K

Change in temperature of liquid from 343K - 273K

Total entalphy

For outlet (top) of Separator

Component 2-butanol

Heat of formation at 273K


(Table 6.11 Entalphy of component in separator 2 (V-102))Heat of formation at 273K

36685.1812

Component

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

2.8770

12204.166

644886.7868

0.0121

52282.6208

632.6197

MEK

81.2460

48019.9784

3901431.165

2.4182

36685.1812

88712.1052

Hydrogen

118.4854

-

-

118.4807

-

-

4546317.952

89344.7249

36685.1812

89344.7249-4546317.952

6.5.8 Heat Exchanger E-107

Assumption

Assume the top product in liquid form

From the manual calculation the mass flow of hydrogen is 0 so the flow rate is negligible

There is no entalphy at stream because it same with the reference condition which is at 1 atm, 25C , liquid

(Liquid) (Liquid) (T = 25 oC = 298KP = 145 Kpa==+) (T= 93oC = 366 KP = 150Kpa==+)


Reference 1 atm , 25C, liquid

2 butanol

Change in temperature of liquid from 298K to 366K

1a =

1a =

1a =

MEK

Change in temperature from 298K to 352.55K

2a =

2a =

Heat of vaporization at 352.55


1b=

A

T

n

50.652

535.50

352.55

0.450

1b=

1b=

1b=31239.5249

Change in temperature of liquid from 352.55K to 366

2a =

2a =

Total entalphy

Table 6.12 Enthalpy component in Heat exchanger E-107

Component

Inlet

Outlet

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

0.0690

12419.2890

1639.8070

0.0690

0

0

MEK

115.9732

42614.6243

4942154.3470

115.9372

0

0

4943794.154

0

4943794.154

6.5.9 Distillation column T-101

Assumption

Liquid phase at the top outlet of distillation column

Liquid phase at the inlet of distillation column

No entalphy of hydrogen since the flowrate is very small

(93C=366K)

(150kPa) (Gas)

(Liquid)

(155kPa)

(70C=343K)

(105C=378K) (150kPa)

(Liquid)

Reference at 25C, 1 atm, liquid

Stream 16

Component For 2-butanol

Change in temperature of liquid from 298 to 343

1 = 1a+1b

1a =

1a =

1a =

Change in pressure of liquid from 1 atm to 1.55atm

1b =

1b =

Total entalphy

For MEK

Change in temperature of liquid from 298K to 343K

2a =

2a =

Change in pressure from 1 atm to 155 atam

2b =

2b =

Total entalphy

Stream 17

For 2-butanol


For MEK


Stream 18

2 butanol

Change int temperature from 298K to 378K

1a =

1a =

1a =


1b =

1b =

Total entalphy

For Mek

Change int temperature from 298K to 378K

2a =

2a =


2b =

2b =

Total entalphy

2 =13511.4764 +

2b =

(Table 6.13 Enthalpy of component in Distillation column T-101)

Component

Inlet

Outlet

Stream 16

Stream 17

Stream 18

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

,

kmol/hr

,

kJ/kmol

kJ/hr

2-butanol

6.2662

7962.5938

49895.2053

0.0690

41815.l289

2885.2439

6.1972

140502.9957

870725.165

MEK

117.2301

7540.1467

883932.1517

115.9732

3013.674

349505.4175

1.2929

13515.9331

17474.7499

933508.8532

352390.6614

888199.9149

933508.8532

LIST OF REFERENCES

Yaws, C. L., (1999). Chemical properties handbook. McGraw-Hill,United State of

America, p.106,132,156,

Chapter 6 Update (1)

Documents

Transcript of Chapter 6 Update (1)