Investigating the performance of a solid oxide fuel cell and a molten carbonate fuel cell combined system

• The SOFC and MCFC combined system is theoretically studied.
• Effect of key operating parameters on the system efficiency is discussed.
• The combined system gives higher electrical efficiency than a single fuel cell.
• The thermal efficiency of the combined system shows an opposite trend.

In this study, the performance of an SOFC (solid oxide fuel cell) and an MCFC (molten carbonate fuel cell) combined system is analyzed. Because SOFCs cannot completely use their fuel, the remaining fuel must be handled effectively. In general, MCFCs can be run at the high operating temperatures required for SOFCs; therefore, the exhaust gas from an SOFC, which still contains useful fuel, can be directly fed into an MCFC. The effects of key operating conditions, such as temperature and fuel utilization, on the system performance are investigated. A simulation of this combined fuel cell system shows an electrical efficiency of 55.22%, which is higher than a single SOFC. The efficiency of the combined fuel cell system can be further improved by adjusting operating conditions.