Danhong Wang

Effects of H2S on hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene on alumina-supported NiMo and NiW catalysts

Abstract Effects of the H2S partial pressure on the catalytic activity and product selectivity of the hydrodesulfurization (HDS) reactions of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) were investigated over the sulfided NiMo/Al2O3 and NiW/Al2O3 catalysts under the deep desulfurization conditions (sulfur concentrations

Elucidation of promotion effect of cobalt and nickel on Mo/TiO2 catalyst using a 35S tracer method

Abstract A series of CoMo and NiMo catalysts supported on TiO 2 with various Co/Mo and Ni/Mo molar ratios were prepared to investigate the relationship between the nature of the support and the promotion effect of Co and Ni. The catalytic activities of these catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) were measured. The HDS activity of CoMo/TiO 2 catalysts increased linearly with the addition of cobalt up to Co/Mo ratio of 0.6 and then decreased slightly above this value. Similarly, the HDS activity of NiMo/TiO 2 catalysts increased linearly with the addition of nickel up to Ni/Mo ratio of 0.6 and remained almost constant above this value. The sulfur mobility on the CoMo/TiO 2 and NiMo/TiO 2 catalysts under the reaction conditions was elucidated by a 35 S radioisotope tracer method using 35 S -labeled DBT. The amount of labile sulfur ( S 0 ) increased linearly with the addition of cobalt or nickel up to molar ratio of 0.6. In contrast, no significant difference in the rate constants of H 2 S release ( k RE ) was observed between Co- or Ni-promoted catalysts and non-promoted Mo catalysts at a given temperature. Therefore, the increase in catalytic activity with the addition of cobalt or nickel can be attributed to an increase in the number of active sites.

Characterization of sulfur exchange reaction between polysulfides and elemental sulfur using a 35S radioisotope tracer method

A sulfur exchange reaction between di-tert-butylpolysulfides and elemental sulfur was examined using a 35S tracer method and the reaction mechanism was discussed.