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US 5,178,750 AGranted
Lubricating oil process
AssigneeTexaco Inc.
InventorTheodore C. Mead
Life of this patent
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Abstract
An improvement has been found in a process for producing Bright Stock from petroleum residuum by propane deasphalting and solvent refining. The extract of solvent refining is cooled to yield an aromatics-lean secondary raffinate which is recycled to propane deasphalting. An improved yield of Bright Stock is achieved over recycling extract to propane deasphalting.
Claims12
In a process wherein a petroleum residuum is passed through first a deasphalting zone and second a solvent refining zone to yield a lubricating oil comprising the steps:
- a. extracting the petroleum residuum with a low molecular weight alkane hydrocarbon solvent in the deasphalting zone to yield a deasphalted lube oil and asphaltic residue,
- b. separating the deasphalted lube oil and asphaltic residue,
- c. extracting the deasphalted lube oil of step b. with an extraction solvent in the solvent refining zone at an extraction temperature to yield an aromatics-lean primary raffinate comprising the lubricating oil and an aromatics-rich primary extract,
- d. separating the primary raffinate and the primary extract, wherein the improvement comprises:
- e. cooling the primary extract of step d. to a temperature 10.degree. F. to 120.degree. F. below the extraction temperature, thereby forming an aromatics-lean secondary raffinate and an aromatics-rich secondary extract,
- f. separating the secondary raffinate and secondary extract,
- g. passing the secondary raffinate of step f. to the deasphalting zone, thereby increasing the yield of lubricating oil from the petroleum residuum.
4 more elements
Dependencies are inferred from the claim text.