Hydrodesulfurization of residual petroleum oil with a sulfided cobalt-molybdenum-alumina catalyst

Claim 1

A process for the hydrodesulfurization of a residual petroleum feedstock containing 1-20 weight-percent asphaltenes and 10-500 ppm metals, which comprises contacting said feedstock in admixture with 500-8,000 SCF/B of hydrogen at a temperature of 650°-850°F and a pressure of 1000-3000 psig, with a catalyst consisting essentially of a sulfided composite of 1-7 weight-percent CoO and 5-20 weight-percent MoO 3 supported on a carrier consisting essentially of activated alumina, said catalyst being further characterized by: a. a total surface area between 150 and 350 m 2 /g; b. a pore volume between 0.3 and 0.8 ml/g; c. an average pore diameter between 40 and 100 A; d. a pore volume in pores above 100 A diameter of between 0.01 and 0.1 ml/g; and e. a particle-form shape having a ratio of external surface area to volume of between 70 and 160 reciprocal inches; said catalyst having been prepared by the steps of: 1. slurrying an alumina hydrogel in an aqueous solution of ammonium molybdate; 2. spray drying the resulting slurry to a water content of about 10-40 weight-percent; 3. mulling the spray-dried composite with water and sufficient acid to give a pH between 3.6 and 6.0; 4. extruding the mulled composite into extrudates having a maximum overall diameter between 0.03 and 0.06 inches and a length between 0.1 and 0.25 inches;