Thermodynamic performance simulation of a coal gasification and SOFC based combined cogeneration plant by energy and exergy analyses
This paper presents a thermodynamic model of a combined cogeneration plant that employs a coal gasifier, a gas cooler and a solid oxide fuel cell (SOFC) upstream of the gas turbine and a downstream HRSG to generate process steam at low pressure. Simulated performance of the plant with respect to variations in some design and operating parameters has been reported. While energy analysis indicates that such a plant would offer a large fuel saving, the exergy analysis identifies the components responsible for major exergy destructions. Higher pressure ratio across the GT is found to improve the energetic as well as exergetic performance of the plant. Higher fuel cell operating temperature is found to have adverse effect on the fuel energy savings ratio of the plant. However, this increases the exergetic efficiency of the SOFC although it does not significantly affect the performance of the other plant components.
Keywords: coal gasification, combined cogeneration, exergetic efficiency, FESR, fuel energy savings ratio, SOFC, solid oxide fuel cells, thermodynamics, simulation, energy analysis, exergy analysis