Abstract: Used Motor Oil is re-refined by direct injection of a superheated, non-hydrogenating recycle vapor. The process operates at low pressures, preferably from atmospheric—10 atmospheres absolute. Preferably a significant amount of the energy required to vapor used motor oil is supplied in the form of increased sensible heat of a recycle vapor stream. Direct injection of superheated vapor reduces or eliminates fouling which can occur when indirect heat exchange is used to supply the heat needed to vaporize used motor oil.

Abstract: A process for the direct contact heating and vaporization of UMO is disclosed. A superheated, but condensable, vapor heats and vaporizes distillable liquid hydrocarbons from a waste motor oil stream, producing an overhead vapor fraction of injected superheated vapor and vaporized boiling range components. This material is cooled and partially condensed to produce lube boiling range liquid hydrocarbons and a vapor phase, which is condensed to produce a recycle liquid phase. Recycle liquid is pumped and then heated to produce superheated vapor for recycle to contact the UMO.