Texaco Inc.

Arthur G Gorneau

Charles W Harrison

Robert M Steinberg

Bruce R Bond

A used lubricating oil comprising lube oil additives, including zinc dithiophosphate is reconstituted. Zinc dithiophosphate is thermally decomposed at a temperature of 400.degree. F. (204.degree. C.) to 1000.degree. F. (538.degree. C.) for a residence time of 10 to 120 minutes. The resulting oil is subjected to vacuum distillation. A zinc-free (i.e. ash free by ASTM D-482) oil is stabilized by catalytic hydrogenation or clay treating to produce a lubricating oil blending stock. About 5 to 25 vol % is recovered as a metal containing bottoms product, useful as asphalt extender. The process is carried out in the absence of chemical demetallizing.

Reconstituting lubricating oil

A used lubricating oil comprising lube oil additives, including zinc dithiophosphate is subjected to reclaiming. Zinc dithiophosphate is thermally decomposed at a temperature of 400.degree. F. (204.degree. C.) to 1000.degree. F. (538.degree. C.) for a residence time of 10 to 120 minutes. The resulting oil is subjected to vacuum distillation. A zinc-free (i.e. ash free by ASTM D-482) distillate oil is useful as marine diesel fuel. About 5 to 25 vol % is recovered as a metal containing bottoms product, useful as asphalt extender. The process is carried out in the absence of chemical demetallizing.

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Houston, TX, United States of America

Arthur G Gorneau