SOFC Stacks Operating under Direct Internal Steam Reforming of Methane

Abstract

AbstractThree SOFC test stacks were operated under conditions of direct internal steam reforming of methane at 750 °C. The influence of anode gas compositions (H2/N2, CH4/H2O, CH4/H2/H2O) on the stack degradation rate has been investigated through long‐term durability testing. It has been found that complete internal steam reforming of methane leads to much faster degradation in comparison to partial pre‐reforming. Possible reason for that is the depletion of Ni‐catalyst due to the formation of volatile Ni(OH)2 at the fuel entrance. Though this effect was observed previously at 950 °C, the present results indicate that it might still play an important role at 750 °C. The lowest degradation was observed with Stack‐3 (ca. 12 mV kh−1 per RU or 1.5% kh−1), which shows also a reasonably high electrical efficiency (>50%) under fuel utilisation of 70.2%.