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US 4,101,414 AGranted
Rerefining of used motor oils
AssigneeUnitech Chemical Inc.
InventorsYang J. Kim, Belton R. Williams
Life of this patent
Estimating the term…
Abstract
Screened and drained used lubricating oil stock is predistilled in a steam stripping still for about 4 hours or more. The thus predistilled used oil then flows to an evaporator for a vacuum distillation at a temperature below the cracking temperature of the stock, about 480.degree.-650.degree. F., to effect an evaporation of the used lubricating oil and its separation from a concentrate by-product of heavy lube hydrocarbons and additives.
Claims13
A method for rerefining used lubricating oils, comprising the steps of:
- predistilling a used oil stock by steam stripping said stock within the range of between about 480.degree. F. and about 650.degree. F. and below the cracking temperature thereof for at least 4 hours, said predistilling step removing NO.sub.x gases, a light oil component and residual water from the stock to leave a predistilled stock;
- thereafter vacuum distilling the predistilled stock at below the cracking temperature thereof in a high vacuum environment, said vacuum distilling step including forming a thin film of the predistilled stock on a heated surface and wiping said film to assist in evaporating the stock and to avoid coking, fouling and buildup of impurities, and said vacuum distilling step including vaporizing a vacuum distilled stock to separate it from a viscous concentrate.
A viscous concentrate formed by the steps of:
- predistilling a used lubricating oil stock by steam stripping said stock at a temperature between about 480.degree. F. and about 650.degree. F. and below the cracking temperature thereof for at least 4 hours, said predistilling step removing NO.sub.x gases, a light oil component and residual water from the stock to leave a predistilled stock;
- thereafter vacuum distilling the predistilled stock by forming a thin film of the predistilled stock on a heated surface and wiping said film to assist in evaporating the stock and to avoid coking, fouling and buildup of impurities, said vacuum distilled taking place below the cracking temperature of the predistilled stock in a high vacuum environment, whereby a viscous concentrate is formed and removed from a vaporized, vacuum distilled stock;
- and collecting said viscous concentrate.
Dependencies are inferred from the claim text.