PARAMETRIC STUDIES FOR A PERFORMANCE ANALYSIS OF A SOFC/MGT HYBRID POWER SYSTEM BASED ON A QUASI-2D MODEL

摘要

Solid oxide fuel cell / micro gas turbine (SOFC/MGT) hybrid power system has been theoretically demonstrated that it can achieve higher thermal efficiency than any other power generation systems. To understand performance characteristics of the SOFC/MGT hybrid power system, it is necessary to analyze sensitivities of operating and design parameters on its performance. In this study, a quasi-2D model for the mathematical modeling of a tubular type indirect internal reforming solid oxide fuel cell (IIR-SOFC) is proposed and applied to a performance analysis of a SOFC/MGT hybrid power system. Using this model, temperature distributions along the longitudinal direction of the IIR-SOFC, which cannot be predicted by the lumped model, are calculated. In addition, sensitivities of parameters governing fuel cell performance such as current density, fuel utilization factor, steam-carbon ratio and parameters governing gas turbine performance such as pressure ratio, turbine inlet temperature, adiabatic efficiencies of compressor/turbine, and heat exchange effectiveness of the recuperator on the performance of the SOFC/MGT hybrid power system are investigated. Results in this study show how a quasi-2D model can improve accuracy of the performance analysis and its implementation to the performance analysis with discussion about sensitivities of design and operating parameters to the performance of the SOFC/MGT hybrid power system.