Two-stage hydrorefining process

A two-stage hydrorefining process which comprises:

• (a) contacting a sulfur-containing heavy hydrocarbonaceous oil feed comprising at least about 0.30 wt. % of an organic sulfur compound selected from the group consisting of dibenzothiophene, dibenzothiophene derivatives, substituted dibenzothiophene and mixtures thereof, with hydrogen in the presence of a nickel-containing hydrorefining catalyst in a first hydrorefining stage maintained at hydrorefining conditions, including a temperature ranging from about 600.degree. to 850.degree. F. and a total pressure ranging from about 60 to 3500 psig, to produce a first hydrorefining stage effluent, including a partially hydrodesulfurized oil, hydrogen sulfide and ammonia;
• (b) removing at least a portion of said hydrogen sulfide and said ammonia from said first hydrorefining stage effluent;
• (c) contacting at least a portion of the resulting hydrorefining stage effluent, including said partially hydrodesulfurized oil, with hydrogen in the presence of a cobalt-containing hydrorefining catalyst in a second hydrorefining stage to produce a hydrocarbonaceous oil having a lower sulfur content than the sulfur content of the partially desulfurized oil of said first hydrorefining stage, and
• (d) recovering a hydrorefined oil having a lower content of said organic sulfur compound than said oil feed of step (a).