Vacuum gas oil is the main raw material for the production of lubricating oil base oil. The vacuum gas oil with high boiling point is fractionated from the side line of vacuum tower by vacuum distillation.

VGO hydrotreating applies to different feeds, coming either directly from the vacuum distillation or from conversion processes (visbreaking, coking,...). The main goal is to prepare adequate feeds for further conversion units, generally fluidized catalytic crackers (FCC) or hydrocracking, mainly by reducing sulfur and nitrogen contents.

The market changes affect refinery configurations. Mild hydrocracking technology allows refiners to convert 20-60% of the VGO feeds, produce high quality cat cracker feedstocks along with a certain quantity of middle distillates.