An energetic analysis of CO2 capture on a gas turbine combining flue gas recirculation and membrane separation

-AIChE, Minneapolis, 21st october 2011 -

Stanbridge Capital Oil & Energy

Bouchra Belaissaoui, Eric Favre

LRGP (Laboratory of Reactions and Process engineering),Nancy, France

G.Cabot, M.S Cabot

CORIA (COmplexe de Recherche Interprofessionnel en Aérothermique), Rouen, France

David Willson

Stanbridge Capital, New York, USA

Introduction : context

Reduction of the cost of CO2 capture on a gas turbine

High CO2 capture ratio (>=90%)

High CO2 purity (>=90%)

Target : 2GJ/ton of recovered CO2

2

Reference (MEA absorption) : 3.5GJ/ton of recovered CO2

With respect of CO2 capture constraints :

Low CO2

content

OEA

3

Introduction : objective

2- Hybrid process*

1- Postcombustion

Separation unit 1

O2/N2

Separation unit

CO2 capture

Gas turbine

cycle

Natural gas

Air

Power

FGR

Separation unit 2

CO2 capture

Gas turbine

cycle

Natural gas Power

FGR

* Favre, E. Bounaceur, R., Roizard, D.(2009),, Sep. Purif. Technol , 68, 30-36.

Moderate O2 enrichment CO2 capture on concentrated

flue gas

Outline

II- Performances for air feeding condition

III- Performances for OEA feeding condition

IV- Conclusion and perspectives

4

I- Membrane unit for CO2 capture

5

Two main variables

in

out

P

P

Pin

Xout, CO2

yCO2 = 0.9

xin,CO2

Pin

Pout

Pout= 1 bar

Membrane selectivity : CO2/N2

Membrane

Pressure ratio :

A single stage membrane module - Cross flow model *

Compressor

P=1 bar

Permeate

Retentate

I- Membrane unit for CO2 capture

- Binary CO2/N2 mixture -

* Bounaceur R. et al, (2006) Energy, 31, 2556-2570.

Membrane unit performances

Prospective membranes

1- Merkel, T.C., Lin, H., Wei, X., Baker, R., 2009. , J. Membrane Sci 2- S.J. Metz, M.H.V. Mulder, M. Wessling,, Macromolecules, 37 (2004) 4590-4597.

3 - Xomeritakis, G., Tsai, C.Y., Brinker, C.J., Sep. Purif. Technol., 42 (2005) 249-257. 3- L. Deng, T.-J. Kim and M.-B. Hagg,, J. Membrane Sci., 340 (2009) 154-163.

4- Krishna, R.,. van Baten, J.M., J. Membrane Sci 360 (2010) 323-333. 6

I- Membrane unit for CO2 capture

7

Outline

II- Performances for air feeding condition

III- Performances for OEA feeding condition

IV- Conclusion and perspectives

I- Membrane unit for CO2 capture

8

Natural gas

Air

Membrane unit

CO2

N2

Flue gas recycling

Gas turbine

Z

1-Z

PIN

XIN

II- Performances for air feeding condition

CO2/N2

Key variable parameters

What is the penalty of CO2 capture on the thermal efficiency of the turbine cycle ?

Compressor

ECO2

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0 0,2 0,4 0,6 0,8 1

XIN

CO

2

the

rm

Recycling ratio, Z

AIR feeding

sto

ech

.lin

e

ref

9

1- Gaz turbine efficiency – complete combustion

XCO2 max = 11%

II- Performances for air feeding condition

Incomplete combustion

domain

- A maximum CO2 fraction of only 11% is obtained

- A OEA combustion is needed if Z larger than 0.669 is wanted

Membrane selectivity CO2/N2=100, yCO2= 0.9 Without

CO2

capture

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200 250 300

R

CC

O2

(GJ/

Ton

CO

2)

PIN (bar)

=2

00

XIN = 0.113

I- Performances for air feeding condition

10

2- Cost of CO2 Capture = Cost of feed compression

Bounaceur R. et al, (2006) Energy, 31, 2556-2570.

MEA absorption reference

E= 8 GJ/ton CO2 Need to enhance the efficiency of the cycle

increase xin,CO2

11

Outline

II- Performances for air feeding condition

III- Performances for OEA feeding condition

IV- Conclusion and perspectives

I- Membrane unit for CO2 capture

Natural gas

Air

Cryogenic

separation

O2 Enriched Air

N2, O2

Membrane

separation

CO2

N2

Gas

Turbine

Z

1-Z

12

III- Performances for OEA feeding condition

Flue gas

recycling

What is the overal thermal efficiency of the turbine cycle ? What is

the total capture cost in GJ/ton CO2 ?

ECO2

EOEA

RCO

COe

RCO

LHVC O

unitthermref

CO 0

2

0

2

0

2

22

*)1( )(

Compression cost OEA unit cost

1- Total cost of CO2 capture on the gas turbine in GJ/ton of recovered CO2

13

III- Performances for OEA feeding condition

with CO2

capture

ton CO2 captured /kg CH4

GJ/kg CH4 Ton O2 /kg CH4 GJ/ton O2

* Göttlicher, G. The energetics of carbon dioxide capture in power plants, US Department of Energy, National Energy Technology Laboratory, 2004.

e : excess of oxygen (e=0.1)

R : CO2 capture ratio

CO20 : 3.67Kg CO2/Kg CH4

2- Gas turbine efficiency

14

III- Performances for OEA feeding condition

- The thermal efficiency passes through a maximum value as Z increases.

- Concentrated CO2 in the flue gas can obtained (xin, CO2 > 0.2)

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0 0,2 0,4 0,6 0,8 1

XIN

CO

2

the

rm

Recycling ratio , Z

OEA feeding

AIR feeding

sto

ech

.lin

e

ref

Membrane selectivity CO2/N2=100, yCO2= 0.9

2

2,5

3

3,5

4

0 5 10 15 20 25 30

CO

2C

ap

ture

Co

st (

GJ/T

CO

2)

PIN (bar)

Cost

15

III- Performances for OEA feeding condition

3- Process optimisation : Minimum CO2 capture cost

- For =50, Emin =3.2 GJ/ton (close to MEA absorption process)

- For =200, Emin =2.6 GJ/ton

MEA absorption reference

16

III- Conclusion and perspectives

For combustion in air with FGR, unacceptable energy requirement is

obtained, even with membrane selectivity of 200

For combustion in OEA, energy requirement down to 2.6 GJ/ton can be

attained.

An energy recovery system on the retentate (high pressure side) could

lower the capture cost

For medium oxygen purity production, alternative technology (PSA,

membrane air separation) could be investigated

Simulation of the hybrid process for multicomponent mixture (O2,NOX,..)

Technico-economical analysis to better evaluate the potential of the

concept

Conclusion

Perspectives

17

An energetic analysis of CO2 capture on a gas turbine combining flue gas recirculation and membrane separation

-AIChE, Minneapolis, 21st october 2011 -

Bouchra Belaissaoui, Gilles Cabot, Marie Sophie Cabot, David Willson and Eric Favre

Stanbridge Capital Oil & Energy

Thank you for your attention