Modeling and Simulation of Heat Recovery Absorption … · Integration to power plant ... Simulate...

Modeling and Simulation of Heat Recovery

Absorption-Based Carbon Capture Process

Adisorn Aroonwilas and Amornvadee Veawab

Energy Technology Laboratory, Faculty of Engineering and Applied Science,

University of Regina

Saskatchewan, Canada S4S 0A2

Presented at

The 9th Trondheim Conference on CO2 Capture, Transport and Storage (TCCS-9)

June 12-14, 2017 Trondhiem, Norway

Outline

Conventional absorption process

Heat recovery absorption process

Objective

Methodology

Simulation results

Integration to power plant

Economic analysis

Conclusions

Acknowledgements

Conventional Absorption Process

Intensive energy requirement for regeneration

High operating cost

CO2 rich loading: 0.35 – 0.45 mol/mol

Energy consumption: 75,000 – 80,000 BTU/lb-mol CO2

(4.0 – 4.2 MJ/kg CO2)

Feed Gas

Treated Gas CO2

Liquid Solvent (Lean)

Liquid Solvent

(Rich)

REGENERATION

COLUMN ABSORPTION

COLUMN 0

2

4

6

8

10

12

14

310 320 330 340 350

Temperature ( K )

Co

lum

n H

eig

ht

(m)

0

2

4

6

8

10

12

14

16

0.2 0.25 0.3 0.35 0.4 0.45 0.5

CO2 loading (mol/mol)

Pco

2 (

kP

a)

Operating

Equilibrium

0

10

20

30

40

50

60

70

80

90

0 0.1 0.2 0.3 0.4 0.5 0.6


CO

2 p

art

ial

pre

ss

ure

(k

Pa

) Typical Amine Process

Equilibrium line

Operating line

Heat Recovery Gas Absorption

Primary features:

Manipulation of column temperature to

maximize CO2 loading in rich-amine solution at

absorber (CO2 loading > 0.5mol/mol)

Recover exothermic heat energy from CO2

absorption and utilize it for solvent regeneration

Heat Recovery Gas Absorption

ABSORBER

REGENERATOR

LEAN-RICH HEAT

EXCHANGER

LEAN HEATER (HEAT-

RECOVERY

EXCHANGER A)

HEAT-

RECOVERY

EXCHANGERS

B & C

HEAT-RECOVERY

CONDENSER

Section 1

Section 2

Section 3

Section 4

Lean liquid

Loaded liquid I

Loaded liquid II

Loaded liquid III

Rich liquid

Gas

TREATED GAS

CONDENSER

Treated gas

LEAN COOLER

PINCHED COOLER

PINCHED COOLER

RICH LIQUID PUMP LEAN LIQUID PUMP

CONDENSATE PUMP

REBOILER

REFLUX CONDENSER

FLASH SEPARATOR

ACCUMULATION DRUM

High purity gaseous component

Ultra rich CO2

loading

Use of

exothermic heat

Elevated Temp

Kinetic-driven

mass transfer

Lower Temp

Thermodynamic

-driven mass

transfer

Objective

Simulate the Heat Recovery Gas Absorption

process (Economic-Technical process model)

Evaluate performance and energy consumption

Compare with typical process scheme

GdY

dzIk a

Py

HCI

A

L

o

e

A i

A L

,

,

GdY

dzk a P y yI

A

G A e A A i , ,

GdY

dzk a P y yI

S

G S e S S i , ,

GdY

dz

L dC

dzI

A

AB

B

G Y CdT

dzh a T TI j p j

j

G

G e G L,

LCdT

dzG Y C

dT

dzG H

dY

dzG H

dY

dzp L

L

I j p jj

G

I R

A

I S

S

, ,

Mass-Transfer:

Energy Balance:

Heat-Transfer:

Material Balance:

Methodology

Input

Information

Result

Representation

Process Flow Model &

Simulator

(Different Process Flow

scheme)

Rate Based Sub-Model

•Absorber design

•Regenerator design

•CO2-Amine reaction

Thermodynamic Model

•Vapor-liq equilibrium

•Speciation

Equipment Design Model

•Pump, blower

•Cooler, heat-exchanger

•Condenser, reboiler

Property Model

(Gas + Liquid)

•Viscosity, density

•Vapor pressure

•Others

Steam Property Model

•Enthalpy, entropy,

•Others

Process flow model (Absorption process)

Process simulation

Simulation conditions: Gas stream Coal-fired flue gas (16% CO2)

Process capacity 1,000 tonne CO2/day

CO2 capture efficiency 90%

Absorption solvent Aqueous MEA solution

Solvent concentration 5.0 kmol/m3

CO2 content after regen. 0.15-0.24 mol CO2/mol MEA

Reboiler temperature 110-120oC

Simulation results:

Dimensions of ABSORBER and REGENERATOR

Heat Exchanger / Reboiler / Condenser / Cooler

Pump / Blower / Storage Tank

Temp. & Conc. Profiles / Equilibrium & Operating Lines

Design & Utility Consumption

Design & Electricity Consumption

Simulation results

Heat Recovery Exchanger-B

Cooling duty = 2.5107 kcal/hr

Rich Amine

T = 27.0oC

Lean Amine

T = 40oC

T = 37.4oC

T = 77.2oC

T = 84.1oC

T = 42.4oC

T = 20oC

T = 20oC

T = 32.0oC

T = 32.2oC

T = 46.7oC T = 74.6oC

Heat Recovery Exchanger-A

Heating duty = 1.7107 kcal/hr

Heat Recovery Exchanger-C

Cooling duty = 5.9106 kcal/hr

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70 80 90

Liquid Temperature (oC)

Co

lum

n h

eig

ht

fro

m b

ott

om

(m

)

27oC at column

bottom

40oC at column top

0

2

4

6

8

10

12

14

16

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7


Pc

o2

(k

Pa

)

Operating

Equilibrium

CO2 loading of 0.59

mol/mol at column

bottom

Temp Profile

0

2

4

6

8

10

12

14

16

18

0 10 20 30 40 50 60 70 80

Temp (C)

Col

umn

heig

ht (m

)

0

2

4

6

8

10

12

14

16

0 0.1 0.2 0.3 0.4 0.5 0.6


Pco2

(kPa

)

Operating

Equilibrium

Energy consumption

Energy Requirement Comparison

-

20,000

40,000

60,000

80,000

100,000

0.1 0.15 0.2 0.25 0.3

Lean CO2 Loading (mol/mol)

En

erg

y R

eq

uir

em

en

t (B

TU

/lb

-mo

l C

O2)

Conventional

This Invention

Energy Saving: 30 – 50 %

CO2 rich loading:

Conventional Process 0.45 mol/mol

Heat Recovery Process 0.55 mol/mol

CO2 flashing before Regen: 30 %

Amine circulation rate:

Conventional Process 570 – 740 m3/h

Heat Recovery Process 440 – 550 m3/h


Components • Coal-fired boiler & Air pre-heater • HP – IP – LP steam turbines • Feed water heater (FWHs) • Low pressure condenser • Boiler feed water pump

Principles • Coal combustion & chemistry • Heat transfer • Thermodynamics of steam cycle

Output • Coal consumption • Thermal efficiency & Net efficiency • Electricity output • Steam quality and flow rate • Emission rate • Flue gas temperature • Flue gas composition

Power-Cycle Module CO2 Capture Module

Design Model • Absorber

• Regenerator + reboiler

• Flue gas blower

• Cooler + heat exchanger

• Pump + piping system

• Storage tank

Output Design specifications

Energy consumption

Utility consumption

Capital & operating cost

$/tonne CO2

Gas conditions

Design Spec. Capture efficiency

Solvent type

Packing type


Energy penalty

MEA conventional (4.8 MJ/kg CO2): 9.7 % point drop

MEA Split-flow (3.1 MJ/kg CO2): 6.4 % point drop

MEA Heat recovery (2.1 MJ/kg CO2): 4.2 % point drop

ST-5

ST-4 ST-3 6000

6000 6000 3669 ST-7

3105.65 ST-1 3106 460

28500 2961

3503 ST-8

440

2952

ST-2 ST-6

9400 1200 ST-11

3224 ST-12 3183 5

4000 ST-13 ST-9 ST-10 2304

3026 1200 420 300

2788 2945 2889

ST-24 ST-23 ST-22 ST-21 ST-20 ST-18 ST-17 ST-16 ST-15

28500 28500 28500 28500 28500 1000 1000 1000 1000

1563 1445 1386 1368 821 576 569 518 216

ST-14

1000

982 ST-19

1000

759

FLUE GAS

CO2 (%) 13.61

N2 (%) 69.85

O2 (%) 3.50

H2O (%) 12.96

SO2 (ppm) 887

HP IP LP

Condenser

FWH-1FWH-2FWH-3FWH-5

FWH-4

FWH-6FWH-7FWH-8

Economizer

Evaporator

Reheater Superheater

Air

Preheater

CO2

Capture

Unit

Coal

ABSORBER

REGENERATOR

LEAN-RICH HEAT

EXCHANGER

LEAN HEATER (HEAT-

RECOVERY

EXCHANGER A)

HEAT-

RECOVERY

EXCHANGERS

B & C

HEAT-RECOVERY

CONDENSER

Section 1

Section 2

Section 3

Section 4

Lean liquid

Loaded liquid I

Loaded liquid II

Loaded liquid III

Rich liquid

Gas

TREATED GAS

CONDENSER

Treated gas

LEAN

COOLER

PINCHED COOLER

PINCHED COOLER


CONDENSATE PUMP

REBOILER

REFLUX

CONDENSER

FLASH

SEPARATOR

ACCUMULATION

DRUM

High purity gaseous

component

ABSORBER

REGENERATOR

LEAN-RICH HEAT

EXCHANGER

LEAN HEATER (HEAT-

RECOVERY

EXCHANGER A)

HEAT-

RECOVERY

EXCHANGERS

B & C

HEAT-RECOVERY

CONDENSER

Section 1

Section 2

Section 3

Section 4

Lean liquid

Loaded liquid I

Loaded liquid II

Loaded liquid III

Rich liquid

Gas

TREATED GAS

CONDENSER

Treated gas

LEAN

COOLER

PINCHED COOLER

PINCHED COOLER


CONDENSATE PUMP

REBOILER

REFLUX

CONDENSER

FLASH

SEPARATOR

ACCUMULATION

DRUM

High purity gaseous

component

40,000 BTU/lb-mole CO2

(2.1 MJ/kg CO2)

Economic analysis

Technical Evaluation • Absorption performance • Solvent regeneration •Others

Flue Gas Condition • Gas flow rate • CO2 content

Design Specification • CO2 capture efficiency • Solvent type • Packing type

Design Model • Absorber • Regenerator + reboiler • Flue gas blower • Cooler + heat exchanger • Pump + piping system • Storage tank

Capital Cost Model • Direct cost (equipment + installation +

labor) • Indirect cost (engineering + legal fee +

contingency

Operating Cost Model • Utility cost Steam, cooling water,

electricity • Operation Operator, maintenance

& repair, lab. Taxes, insurance,

depreciation • General expense

(Administrative)

Engineering Econ. Model • Capital + Operating

• $/tonne CO2

Cost of CO2 capture Capital Cost (90% capture efficiency; 1000

tonnes/day CO2 feed)

10

12

14

16

18

20

22

24

26

28

0.1 0.15 0.2 0.25 0.3


Fix

ed

Cap

ital

Investm

en

t (M

illi

on

$)

Conventional

This Invention

Operating Cost (90% capture efficiency; 1000

tonnes/day CO2 feed)

4

5

6

7

8

9

10

11

12

0.1 0.15 0.2 0.25 0.3


To

tal

Op

era

tin

g C

ost

(Mil

lio

n $

/ year)

Conventional

This Invention

CO2 Capture Cost (90% capture efficiency;

1000 tonnes/day CO2 feed)

5

10

15

20

25

30

35

40

0.1 0.15 0.2 0.25 0.3


Cap

ture

Co

st

( U

S$/T

on

ne C

O2)

Conventional

This Invention

Lower Capital: 20 – 22 million US$

Lower Operating: 8 – 9 million US$/year

Overall Cost: 16 – 26 % Saving

(Saving = 5 – 10 US$/tonne CO2)

Capital Cost Estimation (US$)

Direct cost

Purchased Equipment

Purchased Equipment + delivery

Purchased Equipment installation

Labor&material for insulating equipment

Instrument and control (installed)

Piping (installed)

Electrical systems (installed)

Building (including services)

Yard Improvements

Service facilities (installed)

Land

TOTAL DIRECT COST

Indirect cost

Engineering and supervision

Construction expenses

Legal expenses

Contractor's fee

Contingency

TOTAL INDIRECT COST

FIXED CAPITAL INVESTMENT (FCI)

WORKING CAPITAL

TOTAL INVESTMENT COST

Product Cost EstimationManufacturing cost

Direct Production Costs

Raw materials

Operating labor

Operating supervision

Electricity

Steam

Process water

Cooling water

Maintenance & Repairs

Operating supplies

Laboratory charges

Royalties

Solvent

Fixed Charges

Depreciation

Property taxes

Interest

Insurance

Rent

Plant Overhead Costs

TOTAL MANUFACTURING COST

General expenses

Administrative costs

Distribution & marketing costs

Research & development costs

TOTAL GENERAL EXPENSES

TOTAL PRODUCT COST

Conclusions

The “Heat Recovery Gas Absorption Process” offers

the following features:

Low energy consumption

Low liquid circulating rate

High CO2 rich loading (high capture capacity)

Low energy penalty to the integrated power plant

Reduced capture cost

Process components added = No moving parts

Self-contain unit (Recovery of heat within the process)

Acknowledgments

Faculty of Engineering and Applied Science, University of

Regina

Research Office, University of Regina

SaskPower

Natural Sciences and Engineering Research Council of

Canada (NSERC)

Modeling and Simulation of Heat Recovery Absorption … · Integration to power plant ... Simulate...

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