Patent ID: 7776206

Claim:
A process for producing stable lubricant bright stock having a viscosity, measured at 100° C., of greater than 15 cSt comprising the steps of: a) providing a petroleum vacuum residuum-derived stream having a sulfur content of less than 1% and a nitrogen content of less than 0.5%; b) separating the vacuum residuum-derived stream at a distillation cut point in the range of 1150.degree. F. to 1300.degree. F., into a heavy fraction and at least one light fraction having an upper boiling range of 700° F. or greater; c) hydrocracking the at least one light fraction under lube hydrocracking in a lube hydrocracking zone in the presence of a hydrocracking catalyst and hydrogen under conditions to reduce the concentration of sulfur and nitrogen to suitable levels for hydroisomerization dewaxing; and d) dewaxing at least a portion of the hydrocracked stream in an hydroisomerization zone in the presence of a hydroisomerization catalyst and hydrogen under hydroisomerization conditions to produce a lubricant bright stock having a viscosity, measured at 100° C., of greater than 15 cSt.