Patent ID: 6238551
Filing Date: 2001-05-29
Classification: B01D,C10G,C10M

Abstract:
A method of purifying used oil comprising the steps of:providing a predetermined quantity of used oil;contacting the used oil with a base selected from the group including sodium hydroxide and potassium hydroxide in a predetermined quantity such that the concentration of base in the oil, on a dry weight basis, is between about 0.05 and about 5 weight percent;contacting the used oil with a phase transfer catalyst in a predetermined quantity such that this concentration of catalyst in the base-oil mixture is between about 1.0 and about 10 weight percent of the oil;thoroughly mixing the composition comprising used oil, base, and phase transfer catalyst;heating the composition to a temperature of between about 275.degree. C. and about 350.degree. C.;distilling the resultant mixture;mixing the resulting distillate with a solvent thereby dissolving the contaminants from the petroleum distillate into the solvent;separating the solvent having the contaminants dissolved therein from the petroleum distillate;subsequently separating the contaminants from the solvent and recovering the solvent;recovering any remaining solvent from the petroleum distillate; andreusing the recovered solvent to extract contaminants from subsequent quantities of petroleum distillate.