UC Irvine

The utilization of coal worldwide for electric power generation portends a need for advanced technologies to mitigate the release of carbon. To this end, a novel PSA-based warm gas CO2-removal technology is compared to a state-of-the-art integrated gasification combined cycle (IGCC) power plant with dual-stage Selexol unit for carbon capture using computational methods. The carbon capture in the Selexol case is limited to 83.40 % due to the high methane content in the syngas. The Selexol efficiency is 31.11 %-HHV resulting in a cost-of-electricity (COE) of 148.6 $/MWh with transport, storage, and monitoring (TS&M). Integration of the warm gas CO2-removal technology increases the efficiency to 34.20 %-HHV. Optimization of the water gas shift reactors using thermodynamic gas stability analysis and kinetic reaction modeling results in an efficiency of 35.63 % leading to a reduction in COE to 127.2 $/MWh with TS&M. With the here introduced Ro number, the catalyst volume of isothermal shifting can be reduced by up to 73 %. Due to a higher capture yield of the PSA-technology, carbon capture of 88.6 % can be achieved. In order to reach the U.S. Department of Energy target of 90 % carbon capture, three options are addressed: (1) combustion of syngas in the CO2 purification section while raising steam, (2) syngas reforming in an external adiabatic reformer and (3) syngas recycling to the gasifier. While the syngas recycling option reveals the highest efficiency, the combustion of syngas option is the most economical with a COE of 138.1 $/MWh with TS&M.