Patent ID: 10280371

Abstract:
A process and apparatus for re-refining used lubricating oil (ULO) having thermally unstable additives such as zinc compounds. ULO is mixed with a superheated distillate which may be a recycle stream, an outside stream, or combination, then charged to a vacuum flash or fractionator, to produce an overhead vapor and a residual fraction comprising additives and/or decomposition products thereof. Overhead vapor is condensed to yield a liquid lubricant boiling range product. Superheating may occur in a fired heater, heat exchanger or combination. Mixing of superheated fluid and ULO may occur in a pipe in turbulent flow and/or an in line mixer. Energy efficiency is improved by heat exchanging ULO feed with vapor or liquid product streams. An aromatic rich and thermally stable outside stream such as FCC LCO can be readily superheated. Recovered lubricant boiling range material can be recycled, used as a lube stock or for FCC feed.