US5236474A
Expired / Lapsed
US
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Membrane-based removal of condensable vapors
Assignee: National Aeronautics and Space Administration
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Filing: 1992-09-09
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Granted: 1993-08-17
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Expires: 2012-09-09
Abstract
Abstract A process for removing and recovering a condensable vapor from a gas stream by a membrane contactor is disclosed wherein a gas stream containing a condensable vapor is circulated on one side of hollow fiber membranes while cool extraction fluid is circulated on the other side under a total pressure differential, thereby condensing the condensable vapor in the gas stream, the condensed vapor permeating the membrane and becoming entrained in the cool extraction fluid.
Inventors
- 👤 Richard W. Schofield
- 👤 David D. Newbold
- 👤 Scott B. McCray
- 👤 Dwayne T. Friesen
- 👤 Roderick J. Ray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:08
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/26; B01D53/268; B01D53/22; B01D63/00; B01D63/02; B01D2313/00; B01D2313/22; B01D2313/221
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
128 words
A process for removing and recovering a condensable vapor from a gas stream comprising the steps: (a) providing at least one hollow fiber membrane having a feed side and a permeate side; (b) contacting the feed side of said membrane with a gas stream containing a condensable vapor; (c) contacting the permeate side of said membrane with a cool extraction fluid, the total permeate side pressure being less than the total feed side pressure said total permeate side pressure being maintained by throttling said cool extraction fluid with a throttle valve after said fluid has been pressurized with a liquid circulation pump and prior to contact with said permeate side; and (d) entraining in said cool extraction fluid on the permeate side condensed vapor from said gas stream.
Claim 2
Dependent Claim
128 words
A process for removing and recovering a condensable vapor from a gas stream comprising the steps: (a) providing at least one hollow fiber membrane having a feed side and a permeate side; (b) contacting the feed side of said membrane with a gas stream containing a condensable vapor; (c) contacting the permeate side of said membrane with a cool extraction fluid, the total permeate side pressure being less than the total feed side pressure said total permeate side pressure being maintained by throttling said cool extraction fluid with a throttle valve after said fluid has been pressurized with a liquid circulation pump and prior to contact with said permeate side; and (d) entraining in said cool extraction fluid on the permeate side condensed vapor from said gas stream.
Claim 3
Dependent Claim
15 words
The process of claim 1 including removing said condensed vapor from said cool extraction fluid.
Claim 4
Dependent Claim
26 words
The process of claim 2 including forming a recycle stream by recycling said cool extraction fluid to the permeate side of said membrane in step (c).
Claim 5
Dependent Claim
44 words
The process of claim 3 wherein the method for removing said condensed vapor from said cool extraction fluid comprises removing condensed vapor from said recycle stream at a rate equal to the rate at which condensed vapor is entrained in said cool extraction fluid.
Claim 6
Dependent Claim
43 words
The process of claim 2 wherein the method for removing said condensed vapor from said extraction fluid is selected from the group consisting of distillation, vacuum distillation, membrane distillation, evaporation, vacuum evaporation, liquid/liquid extraction, phase separation, crystallization, adsorption, reverse osmosis, nanofiltration, and pervaporation.
Claim 7
Dependent Claim
27 words
The process of claim 1 wherein said feed side is the outside of said hollow fiber and said permeate side is the lumen of said hollow fiber.
Claim 8
Dependent Claim
31 words
The process of claim 1 wherein said condensable vapor is selected from the vapors of the group consisting of chlorofluorocarbons, chlorinated hydrocarbons, non-chlorinated hydrophobic organics, non-chlorinated hydrophilic organics, and inorganic compounds.
Claim 9
Dependent Claim
24 words
The process of claim 7 wherein said chlorinated hydrocarbons are selected from the group consisting of methylene chloride, trichloroethylene, trichloroethane, carbon tetrachloride, and chlorobenzene.
Claim 10
Dependent Claim
28 words
The process of claim 7 wherein said non-chlorinated hydrophobic organics are selected from the group consisting of benzene, toluene, xylene, ethyl benzene, cyclohexane, propane, butane, hexane, and octane.
Claim 11
Dependent Claim
37 words
The process of claim 7 wherein said non-chlorinated hydrophilic organics are selected from the group consisting of ethanol, methanol, phenols, cresols, acetone, ethyl acetate, methyl ethyl ketone, methyl t-butyl ketone, nitrobenzene, triethyleamine, acetonitriles, dimethyl formamide, and dimethylacetamide.
Claim 12
Dependent Claim
19 words
The process of claim 7 wherein said inorganic compounds are selected from the group consisting of water and ammonia.
Claim 13
Dependent Claim
12 words
The process of claim 1 wherein said hollow fiber membrane is nonporous.
Claim 14
Dependent Claim
12 words
The process of claim 1 wherein said hollow fiber membrane is microporous.
Claim 15
Dependent Claim
12 words
The process of claim 1 wherein said hollow fiber membrane is hydrophilic.
Claim 16
Dependent Claim
27 words
The process of claim 14 said hollow fiber membrane is selected from the group consisting of cellulose acetate, regenerated cellulose, polyimide, polyamide, polymethacrylates, polyvinylalcohol, polyethylacetate, and polyacrylonitrile.
Claim 17
Dependent Claim
12 words
The process of claim 1 wherein said hollow fiber membrane is hydrophobic.
Claim 18
Dependent Claim
53 words
The process of claim 16 wherein said hollow fiber membrane is selected from a group consisting of polysulfone, polyethersulfone, silicone-rubber coated polysulfone, silicone rubber, natural rubber, butyl rubber, polyvinylchloride, tygon, polyarylene ethers, substituted polyacetylenes, polyurethane, hydrophobic polyimides, polyethylene, polypropylene, polybutylene, polyisoprene, polybutadiene, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidine chloride, polyhexafluoro propylene, polystyrene, and copolymers thereof.
Claim 19
Dependent Claim
21 words
The process of claim 1 wherein said cool extraction fluid is selected from the group consisting of hydrophilic and hydrophobic compounds.
Claim 20
Dependent Claim
38 words
The process of claim 18 wherein said cool extraction fluid is a hydrophilic compound and is selected from the group consisting of water, glycerol, ethylene glycol, polyethylene glycol, propylene carbonate, acetonitrile, dimethylacetamide, stearic acid, octanol, phenols, and cresols.
Claim 21
Dependent Claim
28 words
The process of claim 18 wherein said cool extraction fluid is a hydrophobic compound and is selected from the group consisting of dodecane, silicone oil, and petroleum naphtha.
Claim 22
Dependent Claim
15 words
The process of claim 1 wherein said cool extraction fluid comprises a mixture of compounds.
Claim 23
Dependent Claim
20 words
The process of claim 1 wherein said cool extraction fluid consists essentially of the liquid form of said condensable vapor.
Claim 24
Dependent Claim
24 words
The process of claim 1 wherein the difference in temperature between said cool extraction fluid and said feed gas is at least 1° C.
Claim 25
Dependent Claim
24 words
The process of claim 1 wherein the difference in pressure between said permeate side and said feed side is from 0.001 to 1 atm.
Claim 26
Dependent Claim
18 words
The process of claim 1 wherein said feed gas and said cool extraction fluid flow in opposite directions.
Claim 27
Dependent Claim
24 words
The process of claim 1 wherein said feed gas is air, said condensable vapor is water vapor, and said cool extraction fluid is water.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-16 | 1997-02-15 | 1997-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-16 | 2001-02-15 | 2001-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-16 | 2005-02-15 | 2005-08-17 | $7700.00 | Window Closed / Lapsed |