Thermodynamic performance study of an integrated gasification fuel cell combined cycle: an exergy analysis

In this paper, an exergy analysis of an integrated gasification combined cycle (IGCC) with a high-temperature, pressurized solid oxide fuel cell (SOFC) in the topping cycle and a single-pressure nonreheat steam bottoming cycle has been presented. The objective is to identify the components responsible for major exergy losses and to optimize the design and operating parameters with respect to second law performance of the combined cycle. This analysis reveals that the gasifier and SOFC contribute to the major part of the total exergy loss arising from the gasification and electrochemical reactions occurring respectively in these components. A higher pressure ratio across the gas turbine is found to reduce exergy losses in the gasifier, SOFC, and the stack. On the other hand, higher SOFC operating temperature is found to increase the exergy losses in the combustion chamber, economizer, and stack, while it decreases the loss in the SOFC.