Exergy analysis of gas turbine – solid oxide fuel cell–based combined cycle power plant
Fuel cell technology is one of the promising systems for cleaner and competitive alternate power generation systems. When the high temperature fuel cells like solid oxide fuel cell and molten carbon fuel cell are integrated with the gas turbines, the total thermal efficiency of the combined cycle can be obtained greater than 60%. In the present work, thermodynamic analysis of SOFC–GT combined system (3MW) has been carried out for the fuel methane to evaluate the energy efficiency, exergy efficiency and exergy destruction of each component and compared with other fuels like coal gas and ethanol. The effect of compression ratio, turbine inlet temperature and ambient temperature of air on the performance of the system has been analysed. The outcome of the system modelling reveals that SOFC and combustion chamber are the main sources of exergy destruction. At the optimum compression ratio 9 and at the turbine inlet temperature 1,250 K, the total thermal efficiency and the exergy efficiency are found to be 63.3% and 60.85% respectively.
Keywords: SOFC, solid oxide fuel cells, gas turbines, exergy analysis, exergy destruction, combined cycle power plants, thermodynamics, methane, energy efficiency, exergy efficiency, modelling, combustion chamber