Cycle analysis of low and high H2 utilization SOFC/gas turbine combined cycle for CO2 recovery

A major factor in global warming is CO2 emission from thermal power plants, which burn fossil fuels. One technology proposed to prevent global warming is CO2 recovery from combustion flue gas and the sequestration of CO2 underground or near the ocean bed. Solid oxide fuel cell (SOFC) can produce highly concentrated CO2, because the reformed fuel gas reacts with oxygen electrochemically without being mixed with air in the SOFC. We therefore propose to operate multi-staged SOFCs with high utilization of reformed fuel to obtain highly concentrated CO2. In this study, we estimated the performance of multi-staged SOFCs considering H2 diffusion and the combined cycle efficiency of a multi-staged SOFC/gas turbine/CO2 recovery power plant. The power generation efficiency of our CO2 recovery combined cycle is 68.5%, whereas the efficiency of a conventional SOFC/GT cycle with the CO2 recovery amine process is 57.8%.