EFFECT OF H2S AND NH3 ON AROMATICS HYDROGENATION OVER SULFIDED PT ANDNIMO BASED HYDROTREATING CATALYSTS

The influence of H2S or NH3 partial pressure on the rate of toluene hy drogenation over sulfided NiMo and Pt catalysts has been investigated. H2S is an inhibitor for both catalysts and its negative effect is tot ally reversible. NH3 is also a contaminant, however, its negative effe ct is only partially reversible. At very low H2S and NH3 partial press ure and in the same operating conditions, the Pt catalyst is always mo re active per gram of metal than the NiMo catalyst. The NiMo sulfide c atalyst is more sensitive to NH3 than to H2S whereas the Pt catalyst i s more sensitive to H2S than to NH3.