Effect of H2S and NH3 on Aromatics Hydrogenation Over Sulfided Pt and NiMo Based Hydrotreating Catalysts

Abstract
The influence of H2S or NH3 partial pressure on the rate of toluene hydrogenation over sulfided NiMo and Pt catalysts has been investigated. H2S is an inhibitor for both catalysts and its negative effect is totally reversible. NH3 is also a contaminant, however, its negative effect is only partially reversible. At very low H2S and NH3 partial pressure and in the same operating conditions, the Pt catalyst is always more active per gram of metal than the NiMo catalyst. The NiMo sulfide catalyst is more sensitive to NH3 than to H2S whereas the Pt catalyst is more sensitive to H2S than to NH3.