Process for producing stabilizing hydroprocessed lubricating oil stocks by the addition of hydrogen sulfide

摘要

Lubricating oil stocks produced by catalytic dewaxing and subsequent hydrotreating are stabilized against oxidation by the addition of hydrogen sulfide to the feed to the catalytic dewaxing unit. Preferably the hydrotreater effluent is the source of H2S for the catalytic dewaxing unit. The H2S saturates olefins that contribute to oxidation instability and restores antioxidant sulfur compounds such as thiols to the lube stock.