Manufacture of lube base stock oil

Claim 1

In a process for preparing a lube base stock oil from a deasphalted short residuum of a waxy crude, said deasphalted short residuum having a pour point substantially higher than +30° F., said process comprising dewaxing said deasphalted short residuum and recovering a dewaxed residuum having a pour point from about -25° F. to not higher than +30° F., the improvement, whereby increasing the yield of said dewaxed residuum, which comprises: catalytically dewaxing said deasphalted short residuum by contact, in the presence of hydrogen, with a dewaxing catalyst contained in a dewaxing zone, said dewaxing catalyst comprising an aluminosilicate zeolite having a silica/alumina ratio of at least about 12 and a Constraint Index of about 1 to about 12, said contacting being at a temperature from 500° to about 675° F. and at a hydrogn partial pressure at the reactor inlet of about 150-1500 psia, and cascading the effluent from said dewaxing zone to a hydrotreating zone wherein it is contacted with a hydrotreating catalyst at a temperature of 500° to 575° F., thereby increasing the oxidation stability of said dewaxed residuum.