DIR is a kind of vacuum distillation oil refining equipment for reclaiming of used motor oil, this kind of oil refinery plant added catalyst chemicals for separation of harmful materials of used oil and de-coking of the system. The used oil can be cleaned and regenerated in to different viscosity high quality base oil. This system could recycle different kinds of used oil including engine oil, hydraulic oil, machine oil and other lubricants. The light fraction is completely removed and the recycled base oil is of good viscosity, good color, odor, and high lubricating properties.