Exergy and economic analyses of a hybrid solid oxide fuel cell by computer simulation

This study is focused on the exergy and economic analysis of hybrid solid oxide fuel cell with zero-C02 emission by computer simulation with either methane or cthanol as fuels. Configurations were simulated for ethanol and methane fuelled solid oxide fuel ccll system. The results obtained indicate that when the system is fuelled with ethanol, the SOFC stack accounts for about 29 % of the total exergy loss which is the highest exergy loss. In methane system, the component with the highest exergy loss is the CO2 compressor which accounts for 51 % of the total exergy loss. Results also shown that turbine had the highest exergetic efficiency in both configuration. The performance of equipment in both configurations shows that the methane configuration has more equipment with high exergetic efficiency, while the cthanol configuration has more equipment with high irreversibility. Simulated results also shown that the overall exergetic efficiency of the ethanol and methane systems are 24.63 % and 22.33 % respectively, and overall loss work of 1067.36 kW and 783.33 kW respectively indicating that the ethanol fuelled system has the highest rate of irreversibility but conversely also with the highest exergetic efficiency when compared to the methane fuelled system. Economic evaluation of both configurations showed that the capital cost of ethanol and methane system are 8388.56 S/year and 2666.99 $/year respectively indicating that the methane system is more economically viable. Although the ethanol system is more efficient than the methane system, but trade-off between exergetic and economic efficiency favours the selection of methane fuelled configuration over ethanol fuelled configuration for the hybrid SOFC system because the capital cost of the cthanol is far greater than that of methane system.