Thermodynamic Analysis of a Woodchips Gasification Integrated with Solid Oxide Fuel Cell and Stirling Engine

Integrated gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power application is analysed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas which is utilized for feeding the SOFC stacks for electricity production. Unreacted hydrocarbons after SOFC are burned in a catalytic burner and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. The domestic hot water is used as heat sink for the Stirling engine. A complete balance of plant is designed and suggested. Thermodynamic analysis shows that a thermal efficiency of 42.4% based on LHV (lower heating value) can be achieved. Different parameter studies are performed to analysis system behaviour under different conditions. The analysis show that increasing fuel mass flow from the design point results in reducing plant efficiency, whereas power production increases to a maxima before decreasing. Further, not shown here, the optimum utilization factor of SOFC is found to be 65% with suggested input parameters.