Vanadium-ceria catalysts for H2S abatement from biogas to feed to MCFC

Vanadium-based catalysts supported on ceria were studied for the direct and selective oxidation of H2S to sulphur and water at low temperature.Catalysts with two vanadium loading (20-50 wt% of V2O5) were prepared, characterized and tested at temperature of 150-200 °C in order to identify the best catalytic formulation. The most promising catalyst was the sample with the 20 wt% of V2O5 that showed 99% of sulphur selectivity and equilibrium H2S conversion at 150 °C.The effect of the components of a typical biogas stream (CH4, CO2 and H2O) was studied at 150 °C in order to investigate the possible formation of secondary products such COS, CS2. No significant effect was observed in terms of H2S conversion (99%) and selectivity to SO2 (<1%) by adding CH4 and CO2 to the feed stream. Furthermore, the effect of the H2S inlet concentration, temperature, contact time and molar feed ratio (O2/H2S) were also investigated at a reaction temperature of 80 °C.Finally, time on stream tests of 30 h were performed at 80 and 120 °C, in order to examine the catalyst stability.