Performance analysis of integrated gasifier-solid oxide fuel cell power plants with different system configurations

It is desirable to use renewable fuel sources for solid oxide fuel cells (SOFCs) for future combined heat and power (CHP) generation. Biosyngas from biomass gasification is a candidate thanks to the sustainability and the practical carbon neutrality of the biomass resources. Performance of integrated gasifier-SOFC power plants with two different fuel cell system configurations is presented. The integrated system includes a downdraft fixed-bed gasifier, a gas cleaning system and a SOFC CHP system. Anode outlet gas recirculation is employed in one configuration and direct fuel delivery to the anode without recirculation is employed in the other. The results show that system configuration influences the system performance. The integrated system with a direct biosyngas delivery to the fuel cell stack has higher system efficiencies with 21% for the net AC electrical efficiency, 54% for the total CHP system efficiency and 22% for the system exergy efficiency, while the system with ejector-driven anode recirculation gives lower net AC electrical efficiency of 13%, the total CHP system efficiency of 49% and the system exergy efficiency of 15%.