Comparison of Pre-Anode and Post-Anode Carbon Dioxide Separation for IGFC Systems

Abstract

This paper examines the arrangement of a solid oxide fuel cell (SOFC) within a coal gasification cycle, this combination generally being called an integrated gasification fuel cell cycle (IGFC). This work relies on a previous study performed by the National Energy Technology Laboratory (NETL) that details thermodynamic simulations of IGCC systems and considers various gasifier types and includes cases for 90% CO2 capture [1]. All systems in this study assume a Conoco Philips gasifier and cold gas clean up conditions for the coal gasification system (Cases 3 and 4 in the NETL IGCC report). Four system arrangements, cases, are examined. Cases 1 and 2 remove the CO2 after the SOFC anode. Case 3 assumes steam addition, a water-gas-shift (WGS) catalyst and a Selexol process to remove the CO2 in the gas cleanup section, sending a hydrogen-rich gas to the fuel cell anode. Case 4 assumes Selexol in the cold-gas cleanup section as in Case 3; however, there is no steam addition and the WGS takes places in the SOFC, and after the anode. Results demonstrate significant efficiency advantages compared to IGCC with CO2 capture. The hydrogen-rich case (Case 3) has better net electric efficiency compared to typical post-anode CO2 capture cases (Cases 1 and 2), with a simpler arrangement and similar SOFC area. Case 4 gives an efficiency similar to Case 3, but at a lower SOFC power density, or a lower efficiency at the same power density. Carbon deposition concerns are also discussed.

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Identifiers

DOI

10.1115/gt2009-59144

Journal

Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine

Year

2009