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Patent US4880441A successfully refreshed from Google Patents.
US4880441A
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US
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Asymmetric gas separation membranes having graded density skins
Assignee: Permea Inc
•
Filing: 1989-01-12
•
Granted: 1989-11-14
•
Expires: 2009-01-12
Abstract
Abstract Asymmetric gas separation membranes having graded density skins and macrovoid-free morphology comprised of glassy, hydrophobic polymers are disclosed which are effective for separation gases with significante increases in permeation while maintaining equal or greater separation electivity. The membranes have increased free volume and the graded density skin exhibits a density gradient which becomes more dense with increasing proximity to the surface, the membrane effectively decouples the interdependency between permeability and separation selectivity.
Inventors
- 👤 Robert E. Kesting
- 👤 Alfred K. Fritzsche
- 👤 Milton K. Murphy
- 👤 Alan C. Handerman
- 👤 Clint A. Cruse
- 👤 Raymond F. Malon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:32
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/22; B01D61/00; B01D61/14; B01D61/145; B01D69/00; B01D69/02; B01D69/08; B01D69/12; B01D69/1212; B01D69/1213; B01D69/1216; B01D71/00; B01D71/06; B01D71/66; B01D71/68; B01D2325/00; B01D2325/02; B01D2325/022; Y; Y02; Y02C; Y02C20/00; Y02C20/40
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
384 words
A process for the separation of at least one gas of a gaseous mixture from at least one other gas in said gaseous mixture by selective permeation and providing a permeated product containing at least one permeating gas comprising: a. contacting the gaseous mixture with a first surface of a multicomponent gas separation membrane having a graded density skin and essentially macrovoid-free morphology comprised of glassy, hydrophobic polymers, the graded density skin membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy hydrophobic polymers, the graded density skin membrane formed from a dope having a g value of no greater than 2, the polymers of the membrane having a separation factor for the at least one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture which when combined with a coating in occluding contact with the graded density skin membrane provides a multicomponent gas separation membrane which exhibits a selective permeability characterized by at least a 50 percent increase for the at least one gas of the gaseous mixture while maintaining an essentially constant or improved separation factor for the at least one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials, the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one gas of the gaseous mixture; b. maintaining the opposite surface of the multicomponent membrane at a lower chemical potential for said at least one permeating gas than the chemical potential at the first surface; c. permeating said at least one permeating gas into and through the multicomponent membrane; and d. removing from the vicinity of the opposite surface a permeated product having a different proportion of said at least one gas relative to said gaseous mixture.
Claim 2
Dependent Claim
384 words
A process for the separation of at least one gas of a gaseous mixture from at least one other gas in said gaseous mixture by selective permeation and providing a permeated product containing at least one permeating gas comprising: a. contacting the gaseous mixture with a first surface of a multicomponent gas separation membrane having a graded density skin and essentially macrovoid-free morphology comprised of glassy, hydrophobic polymers, the graded density skin membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy hydrophobic polymers, the graded density skin membrane formed from a dope having a g value of no greater than 2, the polymers of the membrane having a separation factor for the at least one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture which when combined with a coating in occluding contact with the graded density skin membrane provides a multicomponent gas separation membrane which exhibits a selective permeability characterized by at least a 50 percent increase for the at least one gas of the gaseous mixture while maintaining an essentially constant or improved separation factor for the at least one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials, the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one gas of the gaseous mixture; b. maintaining the opposite surface of the multicomponent membrane at a lower chemical potential for said at least one permeating gas than the chemical potential at the first surface; c. permeating said at least one permeating gas into and through the multicomponent membrane; and d. removing from the vicinity of the opposite surface a permeated product having a different proportion of said at least one gas relative to said gaseous mixture.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the at least one gas comprises oxygen and the gaseous mixture comprises air.
Claim 4
Dependent Claim
34 words
The process of claim 1 wherein a non-permeating gas of the gaseous mixture is removed from a portion of the multicomponent membrane apart from the portion which is first contacted with the gaseous mixture.
Claim 5
Dependent Claim
25 words
The process of claim 3 wherein the non-permeating gas of the gaseous mixture is comprised of nitrogen and the gaseous mixture is comprised of air.
Claim 6
Dependent Claim
55 words
The process of claim 1 wherein said at least one gas comprises one of hydrogen, helium, ammonia, water vapor, carbon dioxide, hydrogen sulfide, and oxygen and said at least one other gas comprises at least one of the group consisting of carbon monoxide, nitrogen, argon, nitrous oxide, and hydrocarbon of one to six carbon atoms.
Claim 7
Dependent Claim
30 words
The process of claim 1 wherein said at least one gas is an acid gas and said at least one other gas is comprised of an acid or non-acid gas.
Claim 8
Dependent Claim
38 words
The process of claim 1 wherein said at least one gas comprises carbon dioxide and the gaseous mixture comprises carbon dioxide and at least one of carbon monoxide, hydrocarbon of one to six carbon atoms, nitrogen, and oxygen.
Claim 9
Dependent Claim
267 words
A multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability while maintaining essentially constant or improved selectivity comprising: an asymmetric gas separation membrane having a graded density skin and essentially macrovoid-free morphology comprised of glassy, hydrophobic polymers, the graded density skin membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers, the graded density skin membrane formed from a dope having a g value of no greater than 2, the polymers of the graded density skin membrane having a separation factor for one gas of a gaseous mixture, which when combined with a coating in occluding contact with the graded density skin membrane provides a multicomponent gas separation membrane which exhibits a selective permeability characterized by at least a 50 percent increase for the one gas of the gaseous mixture while maintaining an essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials; the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to at least one pair of gases in the mixture.
Claim 10
Dependent Claim
267 words
A multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability while maintaining essentially constant or improved selectivity comprising: an asymmetric gas separation membrane having a graded density skin and essentially macrovoid-free morphology comprised of glassy, hydrophobic polymers, the graded density skin membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers, the graded density skin membrane formed from a dope having a g value of no greater than 2, the polymers of the graded density skin membrane having a separation factor for one gas of a gaseous mixture, which when combined with a coating in occluding contact with the graded density skin membrane provides a multicomponent gas separation membrane which exhibits a selective permeability characterized by at least a 50 percent increase for the one gas of the gaseous mixture while maintaining an essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials; the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to at least one pair of gases in the mixture.
Claim 11
Dependent Claim
89 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the graded density skin asymmetric membrane is formed from a dope of glassy hydrophobic polymers and a solvent system comprised of a Lewis acid and a Lewis base and a Lewis acid:base complex, which solvent system is capable of dissolving the polymers and which complex is readily disassociated by an aqueous coagulation medium, wherein the formed graded density skin asymmetric separation membrane typically contains less than about 0.5% by weight of residual solvent.
Claim 12
Dependent Claim
31 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 9 wherein the dope is comprised of at least 32 weight percent solids of aromatic sulfone polymers.
Claim 13
Dependent Claim
36 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 9 wherein the graded density skin asymmetric separation membrane is formed from a dope having a g value no greater than 1.0.
Claim 14
Dependent Claim
36 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the graded density skin asymmetric separation membrane is formed from a dope having a g value of less than 1.5.
Claim 15
Dependent Claim
31 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the multicomponent gas separation membrane exhibits a selective permeability characterized by at least 100% increase.
Claim 16
Dependent Claim
82 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein with respect to at least one pair of gases consisting of one of hydrogen, helium, ammonia, carbon dioxide, hydrogen sulfide, water vapor and oxygen and one of carbon monoxide, nitrogen, argon, sulfer, hexafluoride, C 1 -C 6 hydrocarbons, the multicomponent gas separation membrane exhibits a determined separation factor which is at least 35% greater than the determined intrinsic separation factor of the material of the coating.
Claim 17
Dependent Claim
62 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the glassy, hydrophobic polymers are comprised of aromatic sulfone polymers, the aromatic sulfone polymers having a repeating polymer unit as follows: ##STR3## where n is an integer of greater than about 50 and copolymers comprised of the above repeating units and blends of the above polymers.
Claim 18
Dependent Claim
40 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the multicomponent gas separation membrane exhibits both an improvement in separation factor and a significant enhancement of gas separation permeability for the one gas.
Claim 19
Dependent Claim
63 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the coating comprises: at least one of poly(siloxane); copolymers incorporating as one constituent poly(siloxane); post-cured cross-linked silicone rubber; polyphosphazene; poly(isoprene); poly(styrene) having a degree of polymerization of about 2 to 20 and aliphatic hydrocarbyl containing organic compounds having from about 14 to 30 carbon atoms per molecule.
Claim 20
Dependent Claim
30 words
The multicomponent gas separation membrane exhibiting significantly enhanced gas separation permeability according to claim 8 wherein the glassy, hydrophobic polymers are comprised of polyether sulfones, polyether imides and copolymers acrylonitrile-styrene.
Claim 21
Dependent Claim
297 words
An asymmetric gas separation membrane comprising: a coating in occluding contact with a graded density skin asymmetric, essentially macrovoid-free membrane of glassy, hydrophobic polymers, the graded density skin being characterized by having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers; the graded density skin membrane formed from a dope having a g value of no greater than 2, the dope containing at least 32 weight percent solids of glassy hydrophobic polymers and a solvent system comprised of a Lewis acid and a Lewis base and a Lewis acid:base complex, which solvent system is capable of dissolving the polymers and which complex is readily disassociated by an aqueous coagulation medium, the polymers of the graded density skin membrane having a separation factor for one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture, wherein the coated membrane exhibits a selective permeability characterized by at least a 50 percent increase for the one gas of the gaseous mixture while maintaining essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials; the determined separation factor of the asymmetric gas separation membrane being greater than the determined separation factor of the graded density skin membrane and greater than the determined intrinsic separation factor of the materials of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one gas of a gaseous mixture.
Claim 22
Dependent Claim
297 words
An asymmetric gas separation membrane comprising: a coating in occluding contact with a graded density skin asymmetric, essentially macrovoid-free membrane of glassy, hydrophobic polymers, the graded density skin being characterized by having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers; the graded density skin membrane formed from a dope having a g value of no greater than 2, the dope containing at least 32 weight percent solids of glassy hydrophobic polymers and a solvent system comprised of a Lewis acid and a Lewis base and a Lewis acid:base complex, which solvent system is capable of dissolving the polymers and which complex is readily disassociated by an aqueous coagulation medium, the polymers of the graded density skin membrane having a separation factor for one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture, wherein the coated membrane exhibits a selective permeability characterized by at least a 50 percent increase for the one gas of the gaseous mixture while maintaining essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and coated with the same coating materials; the determined separation factor of the asymmetric gas separation membrane being greater than the determined separation factor of the graded density skin membrane and greater than the determined intrinsic separation factor of the materials of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one gas of a gaseous mixture.
Claim 23
Dependent Claim
26 words
The gas separation membrane according to claim 19 wherein the formed graded density skin membrane retains less than about 0.5 percent by weight of residual solvent.
Claim 24
Dependent Claim
26 words
A gas separation membrane according to claim 19 wherein the gas separation membrane has both improved separation factor and permeability for the at least one gas.
Claim 25
Dependent Claim
73 words
The gas separation membrane according to claim 19 wherein with respect to at least one pair of gases consisting of one of hydrogen, helium, ammonia, carbon dioxide, hydrogen sulfide, water vapor and oxygen and one of carbon monoxide, nitrogen, argon, sulfur hexafluoride, C 1 -C 6 hydrocarbons, the membrane exhibits a determined intrinsic separation factor of at least about 35% greater than the determined intrinsic separation factor of the material of the coating.
Claim 26
Dependent Claim
37 words
The gas separation membrane according to claim 19 wherein with respect to at least one gas of a gaseous mixture, the material of the coating has a higher permeability constant than does the material of the membrane.
Claim 27
Dependent Claim
36 words
The gas separation membrane according to claim 19 wherein the coating is in occluding contact with at least one surface of the membrane and the coating has an average thickness of up to about 10 microns.
Claim 28
Dependent Claim
55 words
The asymmetric gas separation membrane according to claim 19 wherein the coating comprises: at least one of poly(siloxane), copolymers incorporating as one constituent poly(siloxane); post-cured cross-linked silicone rubber; polyphosphazene; poly(isoprene); poly(styrene) having a degree of polymerization of about 2 to 20 and aliphatic hydrocarbyl containing organic compounds having from about 14 to 30 carbon atoms.
Claim 29
Dependent Claim
54 words
The gas separation membrane according to claim 19 wherein glassy, hydrophobic polymers are comprised of aromatic sulfone polymers, the aromatic sulfone polymers having a repeating polymer unit as follows: ##STR4## where n is an integer of greater than about 50 and copolymers comprised of the above repeating units and blends of the above polymers.
Claim 30
Dependent Claim
33 words
The gas separation membrane according to claim 19 wherein the first heat T g is at least 4° C. greater than the T g of a bulk sample of the glassy, hydrophobic polymers.
Claim 31
Dependent Claim
25 words
The asymmetric gas separation membrane according to claim 19 wherein the glassy, hydrophobic polymers are comprised of polyether sulfones, polyether imides and copolymers of acrylonitrile-styrene.
Claim 32
Dependent Claim
323 words
An asymmetric gas separation membrane having graded density skin and essentially macrovoid-free morphology comprising: glassy, hydrophobic polymers, the membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers, the graded density skin asymmetric separation membrane being produced from spinning solutions having g values of less than 2, which spinning solutions contain at least 32% by weight of the polymers and a solvent system comprised of a Lewis acid and a Lewis base and a Lewis acid:base complex, which solvent system is capable of dissolving the polymers and which complex is readily disassociated in an aqueous coagulation medium, and the membrane retaining less than about 0.5% by weight of residual solvent, the asymmetric separation membrane being capable of providing multicomponent gas separation membranes exhibiting significantly enhanced gas separation permeabilities while maintaining essentially constant or improved selectivity with respect to at least one pair of gases in a gaseous mixture, when the graded density skin asymmetric separation membrane has a coating in occluding contact with the membrane, the coated membrane having at least a 50% increase in permeability for the one gas of the gaseous mixture while maintaining essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and the same coating materials in occluding contact with membranes; the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one pair of gases in the mixture.
Claim 33
Dependent Claim
323 words
An asymmetric gas separation membrane having graded density skin and essentially macrovoid-free morphology comprising: glassy, hydrophobic polymers, the membrane having increased free volume as evidenced by the membrane first heat T g which is greater than the T g of a bulk sample of the glassy, hydrophobic polymers, the graded density skin asymmetric separation membrane being produced from spinning solutions having g values of less than 2, which spinning solutions contain at least 32% by weight of the polymers and a solvent system comprised of a Lewis acid and a Lewis base and a Lewis acid:base complex, which solvent system is capable of dissolving the polymers and which complex is readily disassociated in an aqueous coagulation medium, and the membrane retaining less than about 0.5% by weight of residual solvent, the asymmetric separation membrane being capable of providing multicomponent gas separation membranes exhibiting significantly enhanced gas separation permeabilities while maintaining essentially constant or improved selectivity with respect to at least one pair of gases in a gaseous mixture, when the graded density skin asymmetric separation membrane has a coating in occluding contact with the membrane, the coated membrane having at least a 50% increase in permeability for the one gas of the gaseous mixture while maintaining essentially constant or improved separation factor for the one gas of the gaseous mixture when compared to asymmetric membranes having uniform skins comprised of the same polymers and the same coating materials in occluding contact with membranes; the determined separation factor of the multicomponent gas separation membrane being greater than the determined separation factor of the graded density skin asymmetric separation membrane and greater than the determined intrinsic separation factor of the material of the coating and the polymers comprising the graded density skin membrane exhibit a determined intrinsic separation factor greater than the determined intrinsic separation factor of the materials of the coating with respect to the at least one pair of gases in the mixture.
Claim 34
Dependent Claim
58 words
The asymmetric gas separation membrane having graded density skin and essentially macrovoid-free morphology according to claim 29, characterized as having a graded density skin by scanning electron microscope photographs taken at 50,000 power and the first heat T g is at least 4° C. greater than the T g of a bulk sample of the glassy, hydrophobic polymers.
Claim 35
Dependent Claim
54 words
The gas separation membrane according to claim 29 wherein glassy, hydrophobic polymers are comprised of aromatic sulfone polymers, the aromatic sulfone polymers having a repeating polymer unit as follows: ##STR5## where n is an integer of greater than about 50 and copolymers comprised of the above repeating units and blends of the above polymers.
Claim 36
Dependent Claim
25 words
The asymmetric gas separation membrane according to claim 29 wherein the glassy, hydrophobic polymers are comprised of polyether sulfones, polyether imides and copolymers of acrylonitrile-styrene.
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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) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |