Performance Analysis of the Solid Oxide Fuel Cell and Oxyfuel Combustion Integrated System with Different Recycling Methods

A solid oxide fuel cell (SOFC) has been regarded as the future power generation due to its high efficiency and environmental friendliness. In general, hydrogen used as a fuel in SOFC is produced from hydrocarbon fuel processing that releases carbon dioxide (CO2). Thus, a SOFC power plant requires a CO2-capture process. Among the various types of CO2 separation, the oxyfuel combustion is an interesting approach due to its capability of total CO2 capture with low energy consumption. In this study, the SOFC and oxyfuel combustion integrated system is investigated. To improve its performance, the integrated SOFC system with different recycling schemes: SOFC anode outlet stream (anode recycling) and water condensate stream (steam recycling), is proposed. Pameteric analysis of key design parameters in the SOFC system is performed by considering electricity and heat generation. The simulation results show that the SOFC system with anode recycling provides better electrical efficiency than that with steam recycling due to high utilization of fuel in SOFC and capability of integrating a fuel turbine in the SOFC system. For the SOFC with steam recycling, the fuel turbine cannot be implemented due to insufficient heat for preheating inlet streams.