Activity of spent hydroprocessing catalysts and carbon supported catalysts for conversion of hydrogen sulphide

A gamma-Al2O3, as well as the spent-decoked and corresponding fresh CoMo/Al2O3 and NiMo/Al2O3 catalysts, were used for the direct H2S decomposition and the CO2 aided conversion of H2S. These reactions increased when Ni, Co and Mo were added to Al2O3. The activity of the spent catalysts for the direct HPS decomposition was more than 80% of that of the fresh catalysts. Activated carbons were also used. Their activity for the direct H2S decomposition was significantly enhanced by doping with the Mo species, whereas the CO2 aided reaction was unaffected. Activated carbons alone were active for the CO2 aided conversion of H2S. It was proposed that surface oxide complexes were involved in the latter case.