(111b) Evaluation of Membrane-Based Post-Combustion Separation of CO2 On Power Plant Output

Evaluation of
membrane-based post-combustion separation of CO2 on power plant output

Joseph A. Swisher and
Abhoyjit S. Bhown

Electric Power Research
Institute, Palo Alto, California

Carbon capture, utilization, and storage (CCUS) is an
important set of technologies to reduce the carbon dioxide (CO₂)
emissions resulting from firing fossil fuels to produce electricity. Due to the
large volumes of gas involved, and in the case of post-combustion carbon
capture, the low driving force for separation, carbon capture on the scale of a
typical fossil fuel-fired power plant is projected to require large capital
investment and reduce overall plant efficiency. One benchmark process for CO₂
removal is scrubbing with a solution of monoethanolamine
(MEA) which has been estimated to reduce the output of a coal-fired power plant
by 30%.¹ Several other gas separation technologies with the promise
to reduce the penalty to plant efficiency have been investigated, including
advanced solvents, solid sorbents, and CO₂ perm-selective membranes.
Membrane-based gas separation processes for post-combustion carbon capture have
several potential advantages, including modular scale-up, using no consumable reagents,
and not requiring extraction of steam from the plant's power cycle. Proper
evaluation of a given membrane technology requires coupling models of membrane
performance to models of the rest of the power plant.^2,3,4
In this work, we have developed models of membrane modules from fundamental
mass and energy balances. We developed models for all potential flow regimes, co-,
counter-, and cross-current, both with and without sweep streams. These models
were used to perform parametric studies of separation efficiency under
different assumptions about existing and potential membrane properties. These
membrane models were linked to a model of a power plant in a process simulator
to study the effect of membrane properties and process configurations on the
total area required for 90% capture of CO₂ and the attendant effect
on net power output.

References

1.      Ramezan, M.; Skone,
T. J.; Nsakala, N. Y.; Liljedahl,
G. N. Carbon Dioxide Capture from
Existing Coal-Fired Power Plants; DOE/NETL-401/110907; NETL:
Pittsburgh, PA, 2007.  

2.      Merkel, T. C.; Lin, H.; Wei, X.;
Baker, R. Power plant post-combustion carbon dioxide capture: an opportunity
for membranes. J. Membr. Sci. 2010, 359, 126-139.

3.      Ramasubramanian, K.; Verweij, H.; Winston Ho, W. S.
Membrane processes for carbon capture from coal-fired power plant flue gas: A
modeling and cost study. J. Membr. Sci. 2012, 421?422, 299?310.

4.      Merkel, T. C. et al.
Selective exhaust gas recycle with membranes for CO2 capture from natural gas
combined cycle power plants. Ind. Eng. Chem. Res. 2012, 52, 1150-1159.