Design and Analysis of the Basic Components in a SOFC Anode Cycle

Rolls-Royce Fuel Cell Systems Ltd (RRFCS) is developing a 1MW SOFC hybrid system for power generation with the University of Genoa contributing design of the anode and cathode flow systems. The fuel cell design contains two basic cycles: a cathode cycle to deliver air to the stack and an anode cycle to supply fuel. Both of these are based on a recycling technology where a proportion of the exhaust from each stream is recycled to the inlet of that stream. On the anode side this achieves heating of the fuel to the optimum temperature thereby avoiding undesired carbon deposition. An ejector has been designed to achieve a good mix of the exhaust fuel from the stack with fresh fuel from the pre-processor. Downstream from the ejector a reformer converts methane into hydrogen by steam reforming. The gas produced as a result has the composition and the temperature that generates the optimum condition for the operation of the fuel cell stack. The current paper highlights how the design process of the ejector and a reformer to achieve optimum operation conditions for the fuel cell stack.