Selective catalytic reduction of SO2 with methane for recovery of elemental sulfur over nickel-alumina catalysts

In the current research, to form elemental sulfur, catalytic reduction of sulfur dioxide with methane over Ni-Al2O3 catalysts was studied. By adding nickel as a promoter, the performance of catalyst was enhanced considerably. It was found that Al2O3-Ni (10%) catalyst had the best performance among all the catalysts studied. The addition of more than 10% Ni had no beneficial effect. The reaction was tested at temperature range of 550-800 A degrees C, at the atmospheric pressure, and it was observed that complete conversion and selectivity (more than 99.5%) was achieved by Al2O3-Ni(10%) catalyst at 750 A degrees C. Between molar feed ratio of SO2/CH4 = 1-3, the highest conversion to elemental sulfur combined with low production of H2S and COS, as the undesirable side products, was obtained when molar ratio was equal to 2 (the stoichiometric ratio). Also, the best catalyst showed good long-term stability for SO2 reduction with methane.