Production of high quality lubricant bright stock

摘要

A process for producing a lubricant bright stock from a very heavy feed obtained from a petroleum crude is disclosed. The bright stock produced by the present process has a reduced cloud point and better oxidation stability relative to bright stocks prepared by conventional methods. The process comprises the steps of providing a petroleum residuum-derived stream; separating the residuum-derived stream at a distillation cut point in the range of 1150° F. to 1300° F., into a heavy fraction and at least one light fraction; hydrocracking the at least one light fraction under conditions to reduce the concentration of sulfur and nitrogen to suitable levels for hydroisomerization dewaxing; and dewaxing at least a portion of the hydrocracked stream under hydroisomerization conditions to produce a lubricant bright stock.