Exergy analysis of a cogeneration plant using coal gasification and solid oxide fuel cell

This paper presents exergy analysis of a conceptualized combined cogeneration plant that employs pressurized oxygen blown coal gasifier and high-temperature, high-pressure solid oxide fuel cell (SOFC) in the topping cycle and a bottoming steam cogeneration cycle. Useful heat is supplied by the pass-out steam from the steam turbine and also by the steam raised separately in an evaporator placed in the heat recovery steam generator (HRSG). Exergy analysis shows that major part of plant exergy destruction takes place in gasifier and SOFC while considerable losses are also attributed to gas cooler, combustion chamber and HRSG. Exergy losses are found to decrease with increasing pressure ratio across the gas turbine for all of these components except the gas cooler. The fuel cell operating temperature influences the performance of the equipment placed downstream of SOFC. Copyright (c) 2005 John Wiley & Sons, Ltd.