Elemental sulfur production through regeneration of a SO2-adsorbed V2O5-CoO/AC in H2

H2 regeneration of an activated carbon supported vanadium and cobalt oxides (V2O5-CoO/AC) catalyst–sorbent used for flue gas SO2 removal is studied in this paper. Elemental sulfur is produced during the H2-regeneration when effluent gas of the regeneration is recycled back to the reactor. The regeneration conditions affect the regeneration efficiency and the elemental sulfur yield. The regeneration efficiency is the highest at 330 °C, with SO2 as the product. The production of elemental sulfur occurs at 350 °C and higher with the highest elemental sulfur yield of 9.8 mg-S/g-Cat. at 380 °C. A lower effluent gas recycle rate is beneficial to elemental sulfur production. Intermittent H2 feeding strategy can be used to control H2S concentration in the gas phase and increase the elemental sulfur yield. Two types of reactions occur in the regeneration, reduction of sulfuric acid to SO2 by AC and reduction of SO2 to elemental sulfur through Claus reaction. H2S is an intermediate, which is important for elemental sulfur formation and for conversion of CoO to CoS that catalyzes the Claus reaction. The catalyst–sorbent exhibits good stability in SO2 removal capacity and in elemental sulfur yield.