INHIBITING EFFECTS OF H2S ON HDS ACTIVITY OF COMO AL2O3, NIMO/AL2O3, AND MO/AL2O3/

In order to clarify the relationship between the inhibiting effect of H2S and the promoting effects of Co and Ni on hydrodesulfurization (HD S) activity, HDS reactions of benzothiophene (BT) and dibenzothiophene (DBT) over sulfided CoMo/Al2O3, NiMo/Al2O3, Mo/Al2O3 were carried out in the stream of H-2 or 5% H2S/H-2 using a conventional fixed bed flo w reactor. Both the inhibiting effect of H2S and the promoting effect of Co (or Ni) on an HDS reaction were observed in the reaction of both reactants on every catalyst examined here. HDS activity of Mo/Al2O3 w as most severely inhibited by the addition of H2S. NiMo/Al2O3 was more susceptible to the inhibiting effect of H2S than CoMo/Al2O3. The prom oter eased the inhibiting effect of H2S on HDS activity of these promo ted catalysts. HDS of DBT was more sensitive to the promoting effect o f Co and Ni, and to the inhibiting effect of H2S, than that of BT. The present results supply new points of view with respect to the promoti ng effects of Co and Ni in this catalysis.