US3745747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas purification system
Assignee: GAF Chemicals Corp
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Filing: 1971-03-25
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Granted: 1973-07-17
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Expires: 1991-03-25
Abstract
Abstract A method as disclosed for the recovery of N-alkylated lactams and particularly N-methyl pyrrolidone which may become entrained in gas streams treated with such materials. The lactams are useful, specific, absorbing solvents used in the sweetening and dehydrating of natural gases and also for the selective solvation of various components or impurities from mixed gas streams. During such treatments, the lactams become vaporized or entrained in the gas streams. In the process of this invention, the entrained N-alkyllactam is selectively recovered by the treatment of the gas stream with liquid solvents for the N-alkyllactam. Among suitable solvents for the recovery of the usually used lactams, including methyl pyrrolidone, are the tri- and tetra ethylene glycols and the higher boiling N-alkyl pyrrolidones including N-cyclohexyl pryyolidone.
Inventors
- 👤 H Psyras
- 👤 A Bellisio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:26
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/18; C07D207/22; C07D207/24; C07D207/26; C07D207/263; C07D207/267; B; B01; B01D; B01D1/00; B01D1/14; B01D17/00; B01D17/02; B01D17/0205; B01D3/00; B01D3/34; B01D3/343; B01D3/346; B01D53/00; B01D53/14; B01D53/1493; B01D53/26; B01D53/263; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/507; B01D53/52; B01D53/526; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/60; C01B3/00; C01B3/50; C01B3/52; C07C; C07C7/00; C07C7/11; C07D201/00; C07D201/16; C10; C10L; C10L3/00; C10L3/06; C10L3/10; C01B2203/00; C01B2203/04; C01B2203/0415; C01B2203/0465; C01B2203/0475; C01B2203/048; C01B2203/0485; C01B2203/0495; C10G; C10G2300/00; C10G2300/10; C10G2300/1025
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
12 words
The process of claim 1 wherein the N-alkylated lactam is N-methyl pyrrolidone.
Claim 2
Dependent Claim
27 words
The process according to claim 2 wherein the solvent is an N-alkyl or N-cycloalkyl pyrrolidone having a boiling point at least 50*C above that of N-methyl pyrrolidone.
Claim 3
Dependent Claim
26 words
The process according to claim 1 wherein contacting the gaseous stream with the liquid solvent is by counter-current flow of the gas and the liquid solvent.
Claim 4
Dependent Claim
22 words
The process according to claim 4 wherein the contacting of the counter-current streams takes place in an absorption tower containing bubble plates.
Claim 5
Dependent Claim
32 words
The process according to claim 4 wherein the contacting of the gas stream is by spraying of the liquid solvent counter-current to the flow of the gaseous stream containing the entrained N-alkyllactam.
Claim 6
Dependent Claim
20 words
The method according to claim 1 wherein the gaseous streams were treated with the N-alkyllactam to remove water vapor therefrom.
Claim 7
Dependent Claim
24 words
The process according to claim 1 wherein the gaseous streams are treated with the N-alkyllactam to sweeten them by removal of acidic constituents therefrom.
Claim 8
Dependent Claim
25 words
The process according to claim 8 wherein the acidic constituents include sulfur compounds and the gaseous streams are treated to remove the sulfur compounds therefrom.
Claim 9
Dependent Claim
17 words
The method according to claim 1 wherein the gas streams are treated to remove sulfur dioxide therefrom.
Claim 10
Dependent Claim
25 words
The method according to claim 7 wherein the gaseous streams are treated with the N-alkyllactam to simultaneously remove water vapor and the acidic components therefrom.
Claim 11
Independent Claim
245 words
A method for the recovery of N-alkyllactams vaporized and/or entrained in a gaseous stream upon treatment therewith comprising: a. contacting said treated gaseous stream having vaporized and/or entrained N-alkyllactams therein with a liquid solvent for said N-alkyllactams in a scrubber zone, said liquid solvent consisting essentially of a liquid polyethylene glycol having a boiling point higher than that of said vaporized and/or entrained N-alkyllactams, said liquid solvent absorbing and thus recovering said vaporized and/or entrained N-alkyllactams present in said treated gas stream; b. withdrawing said liquid solvent having recovered N-alkyllactams absorbed therein from said scrubber zone; c. separating said liquid solvent from said absorbed N-alkyllactams in a regeneration zone for recycling of said liquid solvent to said scrubber zone, said N-alkyllactams separated from the liquid solvent being recycled for use in the further treatment of additional quantities of said gaseous stream to be treated; and d. withdrawing the treated gaseous stream from said scrubber zone, said stream having substantially all of the vaporized and/or entrained N-alkyllactam content of the treated gaseous stream passed to said scrubber zone removed therefrom, whereby the treatment of the gaseous stream with N-alkyllactams is accomplished and the treated gaseous stream is withdrawn without appreciable loss of said N-alkyllactams, said loss being minimized by the contact of said treated gaseous stream with the liquid solvent in said scrubber zone, the N-alkyllactams and the liquid solvent being effectively and conveniently regenerated for contact with additional quantities of the gaseous stream being treated.
Claim 12
Dependent Claim
24 words
The method of claim 12 in which said liquid polyethylene glycol is taken from the group consisting of di-, tri- and tetra ethylene glycol.
Claim 13
Dependent Claim
24 words
The method of claim 12 in which said liquid solvent has a boiling point at least 25*C above that of said N-alkyllactams being recovered.
Claim 14
Dependent Claim
13 words
The method of claim 13 in which said liquid solvent comprises triethylene glycol.
Claim 15
Dependent Claim
14 words
The method of claim 13 in which said liquid solvent comprises tetra ethylene glycol.
Claim 16
Dependent Claim
44 words
The method of claim 12 in which said vaporized and/or entrained lactam comprises N-methyl pyrrolidone, the liquid solvent having a boiling point above that of said N-methyl pyrrolidone being taken from the group consisting of di-, tri-, and tetra ethylene glycol and N-cyclohexyl pyrrolidone.
Claim 17
Dependent Claim
13 words
The method of claim 17 in which said liquid solvent comprises triethylene glycol.
Claim 18
Dependent Claim
13 words
The method of claim 17 in which said liquid solvent comprises N-cyclohexyl pyrrolidone.
Claim 19
Dependent Claim
24 words
The method of claim 17 in which said liquid solvent has a boiling point at least 25*C above that of said N-alkyllactams being recovered.
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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |