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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