Calculation of a standard reformed biogas composition and testing on SOFC anode powders

Abstract

A standard reformed biogas composition, based on a 63% CH4 37% CO2 input biogas, was defined by calculation. It is designed to resemble the composition of biogas that would enter a real SOFC stack, assuming 80% fuel utilization, and 25% recirculation of the anode off-gas. It is thermodynamically impervious to coking above 720°C. This gas composition was then used to test the catalytic reforming performance of nickel powder and La0.8Ce0.1Ni0.4Ti0.6O3-δ at 900°C in the standard reformed biogas. No coking was seen on the powder samples by visual inspection after this test. The La0.8Ce0.1Ni0.4Ti0.6O3-δ is designed to exsolve Ni nanoparticles when reduced. SEM pictures of the post-test sample show some small particles that may be exsolved nanoparticles, but further investigation is needed to confirm this. Ni powder was the better reforming catalyst, but sintered extensively in the 3 h test. The La0.8Ce0.1Ni0.4Ti0.6O3-δ also showed reforming capability, and much better microstructural stability in the standard reformed biogas.