Patent attributes
A process to re-refine used petroleum oils by extraction with aliphatic solvents, wherein after eliminating the extract solvent, the process consists of the following treatments, (a) flash, continuous vaporization, at atmospheric pressure or near atmospheric pressure, to separate the light fractions, in the presence of small amounts of a basic compound or a reducing agent or a combination of both and (b) continuous distillation, in a fractionating column, of the bottom liquid obtained in stage (a), under vacuum and moderate temperatures, in the presence of a basic compound or a reducing compound or a combination of both, with recirculation from the bottom of the column to its feed; separating, as lateral extractions, the vacuum gas-oil or spindle oil and the lubricant bases and, as bottom product, a fuel-oil or asphaltic component.
