Chemistry of H2S over the surface of Common solid sorbents in industrial natural gas desulfurization

Abstract

The chemistry on sorptive H2S removal in industrial natural gas desulfurization was reviewed on mechanistic aspects of H2S adsorption/sorption over the surface of activated carbon, zeolite/molecular sieve, zinc oxide, copper oxide, and iron oxide as representative industrial common sorbents. H2S removal of natural gas underwent through weak chemisorption over the surface of activated carbon and zeolite/molecular sieve and dissociative chemisorption over the surface of ZnO, CuO, and Fe2O3 at ambient or relatively low temperature. Dissociative chemisorption over the oxides concomitantly occurred with lattice oxygen replacement by sulfur migration into bulk of oxides, which contributes to higher H2S removal capacity. The infrared spectroscopy and X-ray photoelectron spectroscopy studies elucidated the influence of the presence of impurities, such as CO2 or H2O on H2S removal over each surface. The advantages and disadvantages of industrially preferred H2S removal sorbents, CuO and Fe2O3, were highlighted especially on the role of oxidation state. At last, the discussion of spent sulfided sorbents was extended to the environmental and safety aspect.