Fuel-Adaptability Analysis of Intermediate-Temperature-SOFC/Gas Turbine Hybrid System With Biomass Gas

Abstract

Abstract The tolerance and adaptability to various kinds of fuels make intermediate-temperature solid oxide fuel cell (IT-SOFC) and gas turbine (GT) hybrid system one of the most attractive technologies in the future energy market. In this paper, based on a detailed model established on matlab/simulink, a thermodynamic analysis of IT-SOFC/GT hybrid system fueled with different types of biomass gases is presented. During the process of this research, the composition fluctuations of CH4, H2, CO, CO2, N2, and H2O are considered to simulate the practical situation. Operating states of IT-SOFC/GT hybrid system fueled with wood chip gasified gas and farm biogas are compared under the same power scale of 180 kW. Performance and safety evaluations of hybrid system in response to composition fluctuations of wood chip gas and farm biogas are carried out. Results show that the hybrid system can reach an efficiency of 60.78% with wood chip gas and 59.09% with farm biogas. Meanwhile, with each composition of wood chip gas varying from 80% to 120%, the IT-SOFC/GT hybrid system could maintain the electrical efficiency higher than 59%. However, in the case of farm biogas, the efficiency of system drops to as low as 55%. It is also found that composition fluctuations of H2 in wood chip gas and CH4 in farm biogas leave the most significant effects on system performance. For safety consideration, fluctuation range of CH4 in farm biogas should be controlled between 86% and 116%; otherwise, failure of gas turbine would occur due to unsafe operating temperatures. Compared with wood chip gas, operation of IT-SOFC/GT hybrid system with farm biogas requires more water vapor available to prevent failure of the reformer due to carbon deposition.