# US 9,751,053 B2 · Asymmetric integrally-skinned flat sheet membranes for H2 purification and natural gas upgrading

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- Number: US 9,751,053 B2
- Document ID: US9751053B2
- Status: Granted
- Kind: B2
- Application number: 14/497,743
- Filed: 2014-09-26
- Published: 2016-03-31
- Granted: 2017-09-05
- Earliest claimed: 2014-09-26
- Assignees: Uop LLC
- Applicants: Uop LLC
- Inventors: Chunqing Liu; Howie Q. Tran
- Web page: https://patentgrep.com/patent/US9751053B2

## CPC

- B01D 71/68: Polysulfones; Polyethersulfones
- B01D 53/228: {characterised by specific membranes}
- B01D 67/009: {with wave-energy, particle-radiation or plasma}
- B01D 69/06: Flat membranes
- B01D 71/64: Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
- B01D 2323/30: Cross-linking
- B01D 2323/345: UV-treatment
- B01D 2325/0231: Dense layers being placed on the outer side of the cross-section
- B01D 2325/04: Characteristic thickness
- Y02C 20/40: of CO2
- Y02P 20/129: Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

An asymmetric integrally-skinned flat sheet membrane comprising a miscible blend of an aromatic polyethersulfone (PES) polymer and an aromatic polyimide polymer is used for gas separations such as hydrogen purification, separation of hydrogen and methane and to separate other gases and liquids. UV radiation may be applied to the surface of the membrane for improved properties.

## Claims

### Claim 1

An asymmetric integrally-skinned flat sheet gas separation membrane comprising a highly porous, non-selective symmetric woven Nylon fabric backing, a miscible blend of an aromatic polyethersulfone (PES) polymer and an aromatic polyimide polymer that comprises a plurality of repeating units of formula (I)
wherein X1 is selected from the group consisting of
wherein X2 is selected from the group consisting of
wherein n and m are independent integers from 20 to 500 wherein said asymmetric integrally-skinned flat sheet membrane has a layer of said miscible blend of said PES polymer and said aromatic polyimide polymer with a thickness from 60 microns to 230 microns, and wherein said membrane has a hydrogen over methane selectivity of at least 100.

### Claim 2 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 wherein the surface of said layer of miscible blend is UV cross-linked.

### Claim 3 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 wherein the weight ratio of said PES polymer to said aromatic polyimide polymer is in a range of 1:5 to 5:1.

### Claim 4 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 comprises PES and aromatic polyimide polymer chain segments where at least part of these polymer chain segments are cross-linked to each other through direct covalent bonds by exposure to UV radiation.

### Claim 5 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 wherein said aromatic polyimide polymer is selected from the group consisting of poly(3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline); poly(3,3′,4,4′-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline) and poly(3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride-pyromellitic dianhydride-3,3′,5,5′-tetramethyl-4,4′-methylene dianiline).

### Claim 6 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 comprising a blend of said PES polymer and poly(3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride- 3,3′,5,5′-tetramethyl-4,4′-methylene dianiline).

### Claim 7 (depends on 1)

The asymmetric integrally-skinned flat sheet membrane of claim 1 comprising a blend of said PES polymer and poly(3,3′,4,4′-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride- 3,3′,5,5′-tetramethyl-4,4′-methylene dianiline).