초록 ▼

A stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the pores on the relatively porous, thin, dense skin layer of the membrane comprises a hydrophilic polymer such as chitosan or sodium alginate, a metal salt such as silver

A stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the pores on the relatively porous, thin, dense skin layer of the membrane comprises a hydrophilic polymer such as chitosan or sodium alginate, a metal salt such as silver nitrate, or a mixture of a metal salt such as silver nitrate and hydrogen peroxide and the asymmetric integrally-skinned polymeric membrane comprises a relatively porous, thin, dense skin layer as characterized by a CO2 permeance of at least 200 GPU and a CO2 over CH4 selectivity between 1.1 and 10 at 50° C. under 50-1000 psig, 10% CO2/90% CH4 mixed gas feed pressure. The present invention further includes a method of making these membranes and their use for olefin/paraffin separations, particularly for propylene/propane and ethylene/ethane separations.

대표청구항 ▼

1. A stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the pores on a relatively porous, thin, dense skin layer of the membrane comprises a hydrophilic polymer, a metal salt or a mixture of a metal salt and hydrogen peroxide

1. A stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the pores on a relatively porous, thin, dense skin layer of the membrane comprises a hydrophilic polymer, a metal salt or a mixture of a metal salt and hydrogen peroxide, wherein said asymmetric integrally-skinned polymeric membrane comprises the relatively porous, thin, dense skin layer is characterized by a CO2 permeance of at least 200 GPU and a CO2 over CH4 selectivity between 1.1 and 10 at 50° C. under 50-1000 psig, 10% CO2/90% CH4 mixed gas feed pressure. 2. The stable high performance facilitated transport membrane of claim 1 wherein said metal salt comprises silver nitrate. 3. The stable high performance facilitated transport membrane of claim 1 comprising a polymer selected from a group consisting of a polyimide, a blend of two or more different polyimides, and a blend of a polyimide and a polyethersulfone. 4. The stable high performance facilitated transport membrane of claim 3 wherein the polyimide is selected from the group consisting of poly(2,2′-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline) polyimide derived from a polycondensation reaction of 2,2′-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) with 3,3′,5,5′-tetramethyl-4,4′-methylene dianiline (TMMDA), poly(3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline) polyimide derived from the polycondensation reaction of 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA) with TMMDA, poly(3,3′,4,4′-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline) polyimide derived from the polycondensation reaction of a mixture of 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) with TMMDA, poly(3,3′,4,4′-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride-2,4,6-trimethyl-1,3-phenylenediamine) polyimide derived from the polycondensation reaction of a mixture of BTDA and PMDA with 2,4,6-trimethyl-1,3-phenylenediamine (TMPDA), poly(3,3′,4,4′-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride-2,4,6-trimethyl-1,3-phenylenediamine-2,4-toluenediamine) polyimide derived from the polycondensation reaction of a mixture of BTDA and PMDA with a mixture of TMPDA and 2,4-toluenediamine (2,4-TDA), and poly(3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline-4,4′-diamino-2-methylazobenzene) polyimide derived from the polycondensation reaction of DSDA with a mixture of TMMDA and 4,4′-diamino-2-methylazobenzene (DAMAB). 5. A method of making a stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the method comprises: (a) preparing the asymmetric integrally-skinned polymeric membrane comprising a relatively porous, thin, dense skin layer and having a CO2 permeance of at least 200 GPU and a CO2 over CH4 selectivity between 1.1 and 10 at 50° C. under 50-1000 psig, 10% CO2/90% CH4 mixed gas feed pressure;(b) preparing a hydrophilic polymer-nipped asymmetric integrally-skinned polymeric membrane by dripping an aqueous solution of a hydrophilic polymer with a concentration in a range of 50 ppm to 5000 ppm onto the surface of said asymmetric integrally-skinned polymeric membrane comprising the relatively porous, thin, dense skin layer prepared in step (a); and(c) preparing the facilitated transport membrane by soaking the relatively porous, thin, dense skin layer of said hydrophilic polymer-nipped asymmetric integrally-skinned polymeric membrane prepared in step (b) in an aqueous solution of a metal salt, or in an aqueous solution of a metal salt and hydrogen peroxide for a sufficient time to form the facilitated transport membrane wherein the relatively porous, thin, dense skin layer of the membrane comprises the metal salt, or a mixture of the metal salt and hydrogen peroxide. 6. The method of claim 5 wherein said metal salt is silver nitrate. 7. The method of claim 5 wherein said stable high performance facilitated transport membrane is in a form selected from the group consisting of hollow fibers, tubes and flat sheets. 8. The method of claim 5 wherein the stable high performance facilitated transport membrane is in a form of a flat sheet having a thickness from about 30 to about 400 μm. 9. The method of claim 5 wherein the stable high performance facilitated transport membrane is in a form of a hollow fiber module comprising from about 1,000 to 1,000,000 parallel, hollow fibers or tubes wherein each hollow fiber has an outside diameter of from about 200 micrometers (μm) to about 700 millimeters (mm) and a wall thickness of from about 30 to about 200 μm. 10. A process for the separation of paraffins and olefins, using a stable high performance facilitated transport membrane comprising an asymmetric integrally-skinned polymeric membrane wherein the pores on the relatively porous, thin, dense skin layer of the membrane comprises a hydrophilic polymer, a metal salt, or a mixture of a metal salt and hydrogen peroxide, the process comprising: (a) providing the stable high performance facilitated transport membrane comprising the asymmetric integrally-skinned polymeric membrane wherein the pores on the relatively porous, thin, dense skin layer of the membrane comprises the hydrophilic polymer, the metal salt, or a mixture of the metal salt and hydrogen peroxide wherein said membrane is permeable to said olefins;(b) contacting a humidified olefins/paraffins mixture feed on one side of said stable high performance facilitated transport membrane to cause said olefins to permeate the membrane; and(c) removing from the opposite side of said membrane a permeate gas composition comprising at least a portion of said olefins which permeated through said membrane. 11. The process of claim 10 wherein said olefins and paraffins are in a gaseous stream produced from stream cracking, catalytic cracking, or the dehydration of paraffins. 12. The process of claim 10 wherein said olefins comprise isobutylene, propylene or ethylene and said paraffins comprise isobutene, propane or ethane. 13. The process of claim 10 wherein said permeate gas composition has a concentration of olefin of 99.5 mass percent.