Microstructure, performance and stability of Ni/Al ₂O ₃ cermet-supported SOFC operating with coal-based syngas produced using supercritical water

Coal gasification is being developed as a technique for clean and effective use of coal, especially low-rank coal. Supercritical water (SCW) gasification has high gasification efficiency at low temperature and can operate directly with wet coal without drying. Solid oxide fuel cells (SOFCs) appear to be an important technology in future as they operate at high efficiency. Therefore, the combination of coal gasification using supercritical water with a SOFC could represent one of the most highly efficient applications for the utilization of coal. In this paper, syngas with the similar compositions from coal gasification by SCW was used for SOFC operation. A Ni-Al ₂O ₃ cermet supported tubular SOFC was fabricated by thermal spraying for the performance test. The influence of syngas on the performance of the tubular SOFC was investigated. The maximum output power density decreased by about 34% as the fuel changed from hydrogen to the syngas at a test temperature of 800°C. The open circuit voltage of the tubular SOFCs presented a trend of a slight decrease with the increase of operating time and the output power density exhibited a trend of increase with the increase of operating time.