LAUSR

Three 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%.