Probex Inc.

Thomas G Murray

Martin R MacDonald

Alexander Db Daspit

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.

Method of rerefining waste oil by distillation and extraction

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.

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Aubrey, TX, United States of America

Thomas G Murray