Review and Outlook on the Utilization of Low-Concentration Coalbed Methane for Power Generation by Solid Oxide Fuel Cells

With the growing global demand for clean energy, more and more attention has been given to the energy conversion efficiency of low-quality fuels. A solid oxide fuel cell (SOFC) is expected to be one of the ideal technologies for clean and efficient utilization of low-concentration coalbed methane (CBM) because it can achieve efficient utilization of low-quality fuels. This review examines the challenges of SOFC technology fueled by low-concentration CBM. In comparison to fuels such as hydrogen and natural gas, low-concentration CBM usually contains a large number of other gas components in addition to methane, which reduces the chemical reactivity of CBM and leads to a decrease in the utilization efficiency. The effects of different carbon-containing fuels on the cell performance of SOFC have been investigated by a great deal of research, and the results reveal that methane tends to be the main source of carbon deposition, whereas oxygen-containing fuels can have a positive effect on carbon deposition. In the current SOFC technology fueled by hydrocarbon fuels, concentration polarization is also a major factor contributing to the lack of durability and stability of the cell, with the exception of carbon deposition and sulfur poisoning. In addition, the temperature and other operating environments also have different degrees of influence on the cell performance in the SOFC technology fueled by low-concentration CBM. Therefore, the development of cell materials and the optimization of the system structure of a low-concentration CBM-fueled SOFC are still key research directions for the future.