Power generation from low-concentration fuel gas via solid oxide fuel cells

Combining solid oxide fuel cells (SOFCs) with municipal solid waste (MSW) gasification for power generation from waste potentially offers a promising synergy of high mass and volume reduction rates and high electrical efficiencies. However, the syngas produced from MSW gasification normally contains a large amount of nitrogen and the total combustible gas content, H₂ and CO, is below 20 vol%. To date, most studies on power generation from waste using SOFCs focus on the utilization of waste-derived biogas, which contains a substantial amount of methane, and the structure of SOFCs is mainly planar. In this work, a systematic evaluation of SOFCs, with both flat tubular and planar structures, operating on low-concentration syngas (∼20 vol%) is performed. The electrochemical performances and dynamic responses under diluted fuel conditions and different H₂: CO ratios are investigated first. Subsequently, the short-term stabilities with different current densities and H₂S concentrations are assessed. Finally, multi-physical simulation is employed to investigate the distribution of different physical fields, particularly the first principal stress, under different fuel concentrations. Results demonstrate that the flat tubular SOFC has a better performance and is capable of resisting short-term H₂S poisoning. Moreover, multi-physical simulation confirms that the maximum first principal stress decreases with the decrease of fuel concentration.