US4073720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reclaiming waste lubricating oils
Assignee: United States Department of Energy
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Filing: 1976-10-22
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Granted: 1978-02-14
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Expires: 1996-10-22
Abstract
Abstract A method for purifying and reclaiming used lubricating oils containing additives such as detergents, antioxidants, corrosion inhibitors, extreme pressure agents and the like and other solid and liquid contaminants by preferably first vacuum distilling the used oil to remove water and low-boiling contaminants, and treating the dried oil with a solvent mixture of butanol, isopropanol and methylethyl ketone which causes the separation of a layer of sludge containing contaminants, unspent additives and oxidation products. After solvent recovery, the desludged oil is then subjected to conventional lubricating oil refining steps such as distillation followed by decolorization and deodorization.
Inventors
- 👤 Marvin L. Whisman
- 👤 John W. Goetzinger
- 👤 Faye O. Cotton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:40
CPC Classifications
C; C10; C10M; C10M175/00; C10M175/005
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
88 words
In a process for reclaiming used lubricating oil wherein the oil is stripped of water and volatile constituents and subsequently subjected to conventional lubricating oil refining steps, the improvement which comprises removal of sludge components of the used oil by contacting the oil with a solvent mixture consisting of about 1 part 2-propanol, about 1 part methyl ethyl ketone and about 2 parts 1-butanol following the stripping step and prior to the conventional refining steps whereby the oil dissolves in the solvent and the sludge components precipitate out.
Claim 2
Dependent Claim
20 words
The process of claim 1 wherein from 3 to 8 parts solvent mixture are contacted with 1 part used oil.
Claim 3
Dependent Claim
13 words
The process of claim 2 wherein the subsequent refining step includes vacuum distillation.
Claim 4
Independent Claim
108 words
A method for purifying used lubricating oils containing detergents, extreme pressure additives and oxidation products and other contaminants comprising: a. vacuum-distilling the used oil to strip H 2 O and volatile materials boiling below 600°-700° F; b. mixing the stripped oil with a solvent mixture consisting of about 1 part 2-propanol, about 1 part methyl ethyl ketone and about 2 parts 1-butanol, whereby the oil dissolves in the solvent and the additives and oxidation products precipitate out as a sludge; c. separating the purified oil-solvent mixture from the sludge; d. separating the purified oil from the solvent mixture; and e. subjecting the purified oil to conventional refining steps.
Claim 5
Independent Claim
108 words
A method for purifying used lubricating oils containing detergents, extreme pressure additives and oxidation products and other contaminants comprising: a. vacuum-distilling the used oil to strip H 2 O and volatile materials boiling below 600°-700° F; b. mixing the stripped oil with a solvent mixture consisting of about 1 part 2-propanol, about 1 part methyl ethyl ketone and about 2 parts 1-butanol, whereby the oil dissolves in the solvent and the additives and oxidation products precipitate out as a sludge; c. separating the purified oil-solvent mixture from the sludge; d. separating the purified oil from the solvent mixture; and e. subjecting the purified oil to conventional refining steps.
Claim 6
Dependent Claim
21 words
The process of claim 4 wherein 3 to 4 parts of solvent mixture are contacted with 1 part stripped used oil.
Claim 7
Dependent Claim
13 words
The process of claim 5 wherein the conventional refining step includes vacuum distillation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |