Removal of H2S and/or SO2 by catalytic conversion technologies

Abstract

Catalysts for selective oxidation and selective reduction of H2S and SO2 to elemental sulfur were developed using stoichiometric amounts of oxygen and hydrogen, respectively. Repetition of the two reactions, called the SPOR process, can be used for removing H2S and/or SOx in tail gas, The selective oxidation catalyst, V/SiO2, exhibited about 95% of sulfur yield in the absence of water and about 86% in the presence of 30% water vapor in the feed at 225 degrees C. The yield is comparable to that of Superclaus catalyst which uses 10 times excess oxygen over the stoichiometric amount. The selective reduction catalyst, CoMo/alumina, exhibited about 60-80% of sulfur yield depending on the SO2 concentration, The presence of water did not affect the sulfur yield if the water content was kept below 11%. The overall reaction was composed of two independent reactions occurring on two different sites: complete hydrogenation of SO2 to H2S on metal phase; and the Claus reaction on acidic alumina support.