Detailed Performance Analysis of a Solid Oxide Fuel Cell: Micro Gas Turbine Hybrid Power System

Performance of a solid oxide fuel cell (SOFC) can be enhanced by converting thermal energy of its high temperature exhaust gas to mechanical power using a micro gas turbine (MGT). A MGT plays also an important role to pressurize and warm up inlet gas streams of the SOFC. Performance behavior of the SOFC is sensitively influenced by internal constructions of the SOFC and related to design and operating parameters. In case of the SOFC/MGT hybrid power system, internal constructions of the SOFC influence not only on the performance of the SOFC but also on the whole hybrid system. In this study, influence of performance characteristics of the tubular SOFC and its internal reformer on the hybrid power system is discussed. For this purpose, detailed heat and mass transfer with reforming and electrochemical reactions in the SOFC are mathematically modeled and their results are reflected to the performance analysis. Effects of different internal constructions of the SOFC system and design parameters such as current density, recirculation ratio, fuel utilization factor, and catalyst density in internal reformer on the system performance are investigated and, as a result, some guidelines for the choice of those parameters for optimum operations of the SOFC/MGT hybrid power system are discussed.