Fuel options for solid oxide fuel cells: a thermodynamic analysis

The eligibility of natural gas (methane), methanol, ethanol, and gasoline as fuels for the generation of electrical power in solid oxide fuel cells (SOFCs) is discussed in terms of efficiency. Each raw fuel was assumed to be processed in a steam reformer to provide a hydrogen-rich gas mixture to the SOFC feedstream. An SOFC system, consisting of an electrochemical section and a reformer, was analyzed thermodynamically assuming initial steam/fuel feed ratios at conditions where carbon deposition is thermodynamically impossible, at atmospheric total pressure, and in the temperature range of 800-1,200 K. Results were obtained in terms of both electromotive force (emf) output and efficiency. Methane seems to be the most appropriate fuel option, with an SOFC system efficiency close to 96%. Furthermore, ethanol and methanol were very promising alternative options (94% and 91%, respectively), while gasoline (83%) utilization requires special reforming conditions.