US4021333A
Expired / Lapsed
US
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Method of rerefining oil by distillation and extraction
Assignee: Lubrizol Corp
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Filing: 1975-08-27
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Granted: 1977-05-03
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Expires: 1995-08-27
Abstract
Abstract Used oil is rerefined by distilling it to remove a volatile forecut followed by a fraction of lubricating viscosity; the latter is then extracted with an immiscible liquid extractant to remove impurities. As optional preliminary steps, the oil may be diluted with a volatile diluent and insoluble impurities removed therefrom, and heated with an aqueous solution of a strongly alkaline material to concentrate metallic constituents (such as metal-containing additives) in a solid sludge.
Inventors
- 👤 Emile Najib Habiby
- 👤 Richard William Jahnke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:19
CPC Classifications
C; C10; C10M; C10M175/00; C10M175/005
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
97 words
A method of recovering oil of lubricating viscosity from used oil which comprises the steps of: (A) Distilling said used oil to remove therefrom a forecut having a viscosity substantially less than that of lubricating oil and a flash point (Tag or Pensky-Martens method) less than 121° C.; (b) continuing the distillation to recover a distillate having substantially the viscosity of lubricating oil; (C) Extracting impurities from the distillate of step B with an organic liquid extractant which is substantially immiscible with said distillate; and (D) Removing said organic liquid and impurities dissolved therein from said distillate.
Claim 2
Independent Claim
97 words
A method of recovering oil of lubricating viscosity from used oil which comprises the steps of: (A) Distilling said used oil to remove therefrom a forecut having a viscosity substantially less than that of lubricating oil and a flash point (Tag or Pensky-Martens method) less than 121° C.; (b) continuing the distillation to recover a distillate having substantially the viscosity of lubricating oil; (C) Extracting impurities from the distillate of step B with an organic liquid extractant which is substantially immiscible with said distillate; and (D) Removing said organic liquid and impurities dissolved therein from said distillate.
Claim 3
Dependent Claim
71 words
A method according to claim 1 wherein the extractant of step C is at least one of the following: Ethanol Diacetone alcohol Ethylene glycol mono-(lower alkyl) ethers Diethylene glycol Diethylene glycol mono-(lower alkyl) ethers o-Chlorophenol Furfural Acetone Formic acid 4-Butyrolactone Lower alkyl esters of lower mono- and dicarboxylic acids Dimethylformamide 2-Pyrrolidone and N-(lower alkyl)-2-pyrrolidones Epichlorohydrin Dioxane Morpholine, lower alkyl and amino-(lower alkyl)morpholines Benzonitrile Di-(lower alkyl) sulfoxides Di-(lower alkyl) (lower alkyl) phosphonates.
Claim 4
Dependent Claim
18 words
A method according to claim 2 wherein the distillation of step B is carried out under reduced pressure.
Claim 5
Dependent Claim
44 words
A method according to claim 3 wherein the extractant of step C has a boiling point at one atmosphere pressure in the range 120°-225° C. and a specific gravity, measured at 20° C. in comparison with water at 4° C., in the range 0.90-1.05.
Claim 6
Dependent Claim
20 words
A method according to claim 4 wherein the extractant of step C is ethylene glycol monomethyl ether, dimethylformamide or N-methyl-2-pyrrolidone.
Claim 7
Dependent Claim
45 words
A method according to claim 2 which includes a preliminary step of adding a diluent, in which said used oil is substantially soluble and which is substantially inert thereto, to said oil, and removing insoluble impurities from the solution of said oil in said diluent.
Claim 8
Dependent Claim
39 words
A method according to claim 6 wherein the diluent has a boiling point at atmospheric pressure no higher than about 150° C. and is selected from the group consisting of aliphatic hydrocarbons, lower alkanols, lower alkanones, and mixtures thereof.
Claim 9
Dependent Claim
18 words
A method according to claim 7 wherein the distillation of step B is carried out under reduced pressure.
Claim 10
Dependent Claim
44 words
A method according to claim 8 wherein the extractant of step C has a boiling point at one atmosphere pressure in the range 120°-225° C. and a specific gravity, measured at 20° C. in comparison with water at 4° C., in the range 0.90-1.05.
Claim 11
Dependent Claim
20 words
A method according to claim 9 wherein the extractant of step C is ethylene glycol monomethyl ether, dimethylformamide or N-methyl-2-pyrrolidone.
Claim 12
Dependent Claim
37 words
A method according to claim 6 wherein, prior to the addition of said diluent, said used oil is heated with an aqueous solution of a strongly alkaline material, said aqeuous solution being about 5-20% alkali by weight.
Claim 13
Dependent Claim
14 words
A method according to claim 11 wherein the strongly alkaline material is sodium hydroxide.
Claim 14
Dependent Claim
18 words
A method according to claim 12 wherein the distillation of step B is carried out under reduced pressure.
Claim 15
Dependent Claim
44 words
A method according to claim 13 wherein the extractant of step C has a boiling point at one atmosphere pressure in the range 120°-225° C. and a specific gravity, measured at 20° C. in comparison with water at 4° C., in the range 0.90-1.05.
Claim 16
Dependent Claim
20 words
A method according to claim 14 wherein the extractant of step C is ethylene glycol monomethyl ether, dimethylformamide or N-methyl-2-pyrrolidone.
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) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |