Hydrodesulfurization of oil feedstock with presulfided catalyst

Claim 1

A process for the desulfurization of a mineral oil feedstock containing organic sulfur compounds, which comprises contacting said feedstock plus added hydrogen, and under hydrofining conditions with a sulfided bed of catalyst comprising cobalt and/or nickel plus molybdenum and/or tungsten supported on a porous carrier which is essentially alumina, said catalyst bed having been converted from its initial oxide form to said sulfided form by a method which comprises passing a fluid sulfiding stream through said catalyst bed, said sulfiding stream comprising at the inlet to said catalyst bed (1) a gas stream comprising hydrogen, (2) sufficient free H 2 S to provide an H 2 S concentration in said gas stream of between about 0.3 and 10.0 vol % and (3) a liquid mineral oil fraction having a 50% boiling point above about 600° F. and containing at least about 0.5 wt.% of native organic sulfur, maintaining contacting temperatures in said bed above about 450° F. but not high enough to convert more than about 90% of said organic sulfur to H 2 S whereby some H 2 S is continuously generated throughout said bed, and while resultant sulfiding of said catalyst bed proceeds toward completion, withdrawing therefrom a total fluid effluent containing less total sulfur than the amount being fed thereto in said sulfiding stream.