Vanadium-Ceria Structured Catalysts for the Selective Partial Oxidation of H2S from Biogas

The reaction of H2S selective partial oxidation to elemental sulfur in the range of temperature of 150-200 degrees C was studied on cordierite honeycomb-structured catalysts. The preparation procedure of catalytic cordierite monoliths has been studied, from the washcoating with CeO2 to the deposition of V2O5 by wet impregnation. Two different preparation washcoating procedures deposition were studied: in one case the washcoat had been already added with the salts precursors of the active species (joint impregnation method), in other case the active species were added only after the deposition step of the washcoat on the monolith, by impregnation in a solution of the salt precursor (distinct impregnation method). The catalysts prepared with the two different methods were characterized and the stability was investigated in catalytic activity tests. The catalysts prepared with the "joint impregnation" method have shown a poor catalytic activity and tendency to the deactivation. Very different results were found for the catalysts prepared with the "distinct impregnation" method, for which the effect of the vanadium content (2-19 V2O5 wt %) was also studied at 200 degrees C. Good catalytic performances were obtained for both samples that have shown a high H2S conversion (similar to 90 %), low SO2 selectivity (2 %) and a high stability.