Thermo-economic modeling and analysis of an NG-fueled SOFC-WGS-TSA-PEMFC hybrid energy conversion system for stationary electricity power generation

Abstract

The natural gas fueled system coupling solid oxide fuel cell, water gas shift reaction, thermal swing adsorption and proton exchange membrane fuel cell (SOFC-WGS-TSA-PEMFC) could have a high efficiency and fast response for power generation. The thermo-economic analyses show that the hybrid system could have a better economy for electricity generation, whose specific electricity cost with LaNi5 as the thermal swing adsorption (TSA) working medium is 4.058 ￠/kW h only, remarkably lower than that of a standard power plant (5.46 ￠/kW h). The sensitivity analysis indicates the low sensitivity of the system to the market price fluctuation. When using the Mg+2 wt%Ni or TiFe metal hydride with the higher hydrogen capacity and the cheaper price as the TSA working medium for H2 production, the specific electricity energy cost can be further reduced to 3.958 ￠/kW h, which could be more economical than that with the traditional pressure swing adsorption or the membrane reactor for H2 production. In addition, the large-scale electricity power generation helps to cut down the system specific cost. These results reveal that the hybrid system could be a promising and economical energy conversion system for stationary electricity power generation.