Abstract: A process for recovering a base oil of lubricating viscosity from used oil in which, following optional pretreatment, used oil is re-refined by distilling it in distillation apparatus having multiple theoretical plates. Impurities are then extracted from the lube range distillate fraction or fractions with a liquid extractant such as N-Methyl-2-Pyrrolidone (NMP) at a temperature below the temperature, if any, of complete miscibility of the extractant and the oil. The oil and extractant are then separated whereupon the extractant is re-used in the process and the oil is subject to further treatment, as necessary, for targeted uses.

Abstract: The invention is directed to a process of reducing the chlorine content of oil as well as its propensity to foul during subsequent distillation processes. The process heats the oil to a temperature in the range of 400 to 700 F and contacts the oil with a non-oxidizing gas, such as steam, for a residence time of at least several minutes. Thereafter the oil may be distilled and/or finished to a base lubricating oil or other distillate product. The oil subject to the process may be used oil, and can be subject to a dewatering or removal of light contaminants treatment prior to being subject to the process.