US3773650A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dewaxing process
Assignee: Exxon Mobil Corp
•
Filing: 1971-03-31
•
Granted: 1973-11-20
•
Expires: 1991-03-31
Abstract
Abstract An improved process for the solvent dewaxing of petroleum oil stocks. The dewaxing solvent is prechilled and added incrementally or continuously at several points along the height of a cooling tower. The oil-solvent mixture is agitated during the chilling step to permit substantially instantaneous mixing of the prechilled solvent with the oil.
Inventors
- 👤 D Hislop
- 👤 J Eagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:03
CPC Classifications
C; C10; C10G; C10G73/00; C10G73/02; C10G73/32; C10G73/06
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
17 words
The process of claim 1 wherein the chilling zone is divided into at least 6 agitated stages.
Claim 2
Dependent Claim
17 words
The process of claim 1 wherein the cold dewaxing sOlvent is a mixture of propylene and acetone.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein the cold dewaxing solvent is chosen from the group consisting of ketones having 3 to 6 carbon atoms and their mixtures.
Claim 4
Dependent Claim
24 words
The process of claim 1 wherein the cold dewaxing solvent is selected from the group consisting of low molecular weight hydrocarbons and their mixtures.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein the cold dewaxing solvent is selected from the group consisting of halogenated hydrocarbons.
Claim 6
Dependent Claim
25 words
The process of claim 1 wherein the degree of agitation in each of said stages is maintained between about 200 and 150,000 modified Reynolds Number.
Claim 7
Dependent Claim
23 words
The process of claim 1 wherein said solvent-oil mixture is cooled in said chilling zone at a rate of about 1*-5*F. per minute.
Claim 8
Dependent Claim
15 words
The process of claim 1 wherein the petroleum oil stock is a lubricating oil fraction.
Claim 9
Dependent Claim
158 words
A process for dewaxing a waxy petroleum oil stock comprising introducing said oil stock into a chilling zone divided into at least 6 agitated stages, introducing a cold dewaxing solvent into each of said agitated stages, maintaining a high degree of agitation in each of said stages so as to effect substantially instantaneous mixing of said solvent and waxy oil in each of said agitated stages while cooling the solvent-waxy oil mixture at an average rate of about 1*-8*F. per minute as it progresses through the chilling zone thereby precipitating a substantial portion of said wax from said mixture under conditions of said high degree of agitation and effecting a final temperature of said mixture in said chilling zone of between about 0* and 50*F., withdrawing the solvent-oil mixture containing precipitated wax from said chilling zone, separating the precipitated wax from the oil-solvent mixture and recovering the petroleum oil stock having a reduced wax content from said mixture.
Claim 10
Dependent Claim
162 words
A process for dewaxing a waxy petroleum oil stock comprising introducing said oil stock into a chilling zone divided into at least 6 agitated stages, introducing a cold dewaxing solvent into each of said agitated stages, maintaining the degree of agitation in each of said stages between about 200 and 150,000 modified Reynolds Number so as to effect substantially instantaneous mixing of said solvent and oil in each of said agitated stages while cooling said mixture at an average rate of about 1*-8*F. per minute as it progresses through the chilling zone thereby precipitating a substantial portion of said wax from said mixture under conditions of said high degree of agitation and effecting a final temperature of said mixture in said chilling zone of between about 0* and 50*F., withdrawing the oil-solvent mixture containing precipitated wax from said chilling zone, separating the precipitated wax from the oil-solvent mixture and recovering the petroleum oil stock having a reduced wax content from said mixture.
Claim 11
Dependent Claim
12 words
The process of claim 11 wherein the cold dewaxing solvent is propylene-acetone.
Claim 12
Dependent Claim
168 words
A process for dewaxing a waxy lubricating oil stock comprising introducing said petroleum oil stock into the top of a chilling zone divided into between about 6 and 50 agitated stages, introducing a cold dewaxing solvent into each of said stages, maintaining the degree of agitation in each of said stages between about 200 and 150,000 modified Reynolds Number so as to effect substantially instantaneous mixing of said solvent and said oil in each of said agitated stages while cooling said mixture at an average rate of about 1*-5*F. per minute as it progresses down the chilling zone thereby precipitating a substantial portion of said wax from said mixture under conditions of said high degree of agitation and effecting a temperature of said mixture in the final agitated stage of between about 0 and 40*F., withdrawing the oil-solvent mixture cOntaining precipitated wax from said chilling zone, separating the precipitated wax from the oil-solvent mixture and recovering a petroleum oil stock having a reduced wax content from said mixture.
Claim 13
Dependent Claim
98 words
A process for separating a wax-oil mixture comprising introducing said mixture, at a temperature above its cloud point, into a chilling zone divided into a plurality of stages, introducing a dewaxing solvent into at least a portion of said stages, maintaining a high degree of agitation in a plurality of the solvent-containing stages so as to effect a substantially instantaneous mixing of said solvent and said wax-oil mixture while cooling said mixture as it progresses through said chilling zone thereby precipitating a substantial portion of said wax from said mixture under conditions of said high degree of agitation.
Claim 14
Dependent Claim
112 words
A process for dewaxing a waxy petroleum oil stock comprising introducing said petroleum oil stock into a chilling zone divided into a plurality of stages, introducing a dewaxing solvent into a plurality of said stages, maintaining a high degree of agitation in each of said stages so as to effect a substantially instantaneous mixing of said solvent and said oil while cooling said solvent-oil mixture as it progresses through said chilling zone thereby precipitating a substantial portion of the wax from said mixture under conditions of said high degree of agitation, separating precipitated wax from said solvent-oil mixture and recovering a petroleum oil stock having a reduced wax content from said mixture.
Claim 15
Dependent Claim
121 words
A process for dewaxing a waxy petroleum oil stock comprising introducing said petroleum oil stock into a chilling zone divided into a plurality of stages, introducing a dewaxing solvent into a plurality of said stages, maintaining a high degree of agitation in each of said stages so as to effect a substantially instantaneous mixing of said solvent and said oil while cooling said solvent-oil mixture at an average rate of about 1*-8*F. per minute as it progresses through said chilling zone thereby precipitating a substantial portion of the wax from said mixture under conditions of said high degree of agitation, separating precipitated wax from the oil-solvent mixture and recovering a petroleum oil stock having a reduced wax content from said mixture.
Claim 16
Dependent Claim
17 words
The process of claim 1 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 17
Dependent Claim
17 words
The process of claim 10 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 18
Dependent Claim
17 words
The process of claim 11 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 19
Dependent Claim
17 words
The process of claim 13 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 20
Dependent Claim
17 words
The process of claim 14 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 21
Dependent Claim
17 words
The process of claim 15 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
Claim 22
Dependent Claim
17 words
The process of claim 16 wherein said dewaxing solvent comprises a mixture of methylethyl ketone and toluene.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |