Catalytic hydroconversion process with catalyst retainer

Claim 1

A catalytic process for the hydroconversion of mineral oil which comprises (a) first contacting a mineral oil feedstock and a hydrogen-containing gas in an upright reaction zone with a layer of spherical hydroconversion catalyst support and/or retainer which is larger than a conventional catalyst subsequently employed in the process and which consists essentially of alumina containing up to 6% by weight of silica as a support, and from about 2 to about 20% by weight of Group VI-B metal and about 0.5 to about 10% by weight Group VIII metal, each in the form of metals, their oxides or sulfides, and having a diameter of greater than 6 mm up to about 30 mm, a surface area above 200 m 2 /gm and a crush strength above 70 pounds, at an elevated temperature of 100°-500° C., a total pressure of 5.0-10,000 psig, a liquid hourly space velocity from about 0.2 to about 12 and from about 300 to 10,000 cubic feet of added hydrogen per barrel of feed, said layer of spherical catalyst support and/or retainer being disposed above and below said conventionally employed catalyst bed having a depth sufficient to require inert pellets, balls or spheres as a retainer and/or support for said conventionally employed catayst; (b) then contacting said feed in said reaction zone with said conventional extruded smaller sized hydroconversion catalyst at the same operating conditions; (c) followed by contacting said feed with another layer of said spherical hydroconversion catalyst support and/or retainer as set out in step (a) and (d) recovering the hydroconverted oil from the reaction zone.