# US 10,500,548 B2 · Composite nanoparticle stabilized core carbon molecular sieve hollow fiber membranes having improved permeance

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- Number: US 10,500,548 B2
- Document ID: US10500548B2
- Status: Granted
- Kind: B2
- Application number: 15/512,100
- Filed: 2015-08-14
- Published: 2017-09-28
- Granted: 2019-12-10
- Earliest claimed: 2014-09-22
- Assignees: Georgia Tech Research Corporation
- Applicants: Georgia Tech Research Corporation
- Inventors: William John Koros; Kuang Zhang
- Web page: https://patentgrep.com/patent/US10500548B2

## CPC

- B01D 69/08: Hollow fibre membranes (manufacture of hollow fibres D01D5/24, D01F1/08)
- B01D 53/228: {characterised by specific membranes}
- B01D 67/0067: {by carbonisation or pyrolysis}
- B01D 67/00793: {Dispersing a component, e.g. as particles or powder, in another component}
- B01D 69/088: {Co-extrusion; Co-spinning}
- B01D 69/1212: {Coextruded layers}
- B01D 69/141: {Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes}
- B01D 71/021: {Carbon}
- B01D 71/0213: {Silicon}
- B01D 67/0076: {Pretreatment of inorganic membrane material prior to membrane formation, e.g. coating of metal powder}
- B01D 69/148: {Organic/inorganic mixed matrix membranes}
- B01D 71/025: {Aluminium oxide}
- B01D 71/027: {Silicium oxide}
- B01D 2256/12: Oxygen
- B01D 2256/16: Hydrogen
- B01D 2256/24: Hydrocarbons
- B01D 2256/245: Methane
- B01D 2257/102: Nitrogen
- B01D 2257/304: Hydrogen sulfide
- B01D 2257/504: Carbon dioxide
- B01D 2257/7022: Aliphatic hydrocarbons
- B01D 2323/18: Pore-control agents or pore formers
- B01D 2323/60: Co-casting; Co-extrusion
- B01D 2325/022: Asymmetric membranes
- B01D 2325/32: Melting point or glass-transition temperatures
- Y02C 20/40: of CO2
- 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]

## Abstract

Disclosed herein are asymmetric multilayer carbon molecular sieve (“CMS”) hollow fiber membranes and processes for preparing the membranes. The processes include simultaneously extruding a core dope containing a polymer and suitable nanoparticles, a sheath dope, and a bore fluid, followed by pyrolysis of the extruded fiber.

## Claims

### Claim 1

A process for preparing an asymmetric multilayer carbon molecular sieve (CMS) hollow fiber membrane comprising
a. co-extruding a core dope and a sheath dope through a spinneret to produce at least one multilayer CMS membrane precursor fiber,
wherein the core dope comprises a first polymer, a first solvent, and a plurality of nanoparticles, and
wherein the sheath dope comprises a second polymer and a second solvent; and
b. pyrolyzing the at least one multilayer CMS membrane precursor fiber to form an asymmetric multilayer CMS hollow fiber membrane.

### Claim 2 (depends on 1)

The process of claim 1, wherein the first and second polymers are the same polymer.

### Claim 3 (depends on 1)

The process of claim 1, wherein the first and second polymers are different polymers.

### Claim 4 (depends on 3)

The process of claim 3, wherein the first polymer has a glass transition temperature and the second polymer has a glass transition temperature that is equal to or greater than the glass transition temperature of the first polymer.

### Claim 5 (depends on 3)

The process of claim 3, wherein the first polymer has a glass transition temperature and the second polymer has a glass transition temperature that is equal to or lower than the glass transition temperature of the first polymer.

### Claim 6 (depends on 1)

The process of claim 1 wherein the plurality of nanoparticles in the core dope are hydrophobic.

### Claim 7 (depends on 1)

The process of claim 1 wherein the plurality of nanoparticles in the core dope are polyhedral oligomeric silsesquioxane (“POSS”) silica nanoparticles.

### Claim 8 (depends on 1)

The process of claim 1, wherein the at least one CMS membrane precursor fiber comprises a core layer comprising the extruded core dope and a sheath layer comprising the extruded sheath dope, the core layer having a substantially annular cross-section and the sheath layer having a substantially annular cross-section adjacent to and radially outward from the core layer, and wherein the core layer comprises 25-40 wt % nanoparticles based on polymer weight.

### Claim 9 (depends on 1)

The process of claim 1, wherein the at least one CMS membrane precursor fiber comprises a core layer comprising the extruded core dope and a sheath layer comprising the extruded sheath dope, the core layer having a substantially annular cross-section and the sheath layer having a substantially annular cross-section adjacent to and radially outward from the core layer, and wherein the core layer comprises 10-25 wt % nanoparticles based on polymer weight.

### Claim 10 (depends on 1)

The process of claim 1, further comprising prior to pyrolyzing the CMS hollow fiber membrane precursor, contacting the CMS hollow fiber membrane precursor with one or more solvent exchange materials comprising a modifying agent in an amount effective to improve the gas permeance of the asymmetric multilayer CMS hollow fiber membrane.

### Claim 11 (depends on 10)

The process of claim 10, wherein the modifying agent is a silane.

### Claim 12

A process for preparing a multilayer hollow fiber membrane comprising:
a. co-extruding a core dope and a sheath dope through a spinneret to produce at least one multilayer hollow fiber membrane precursor,
wherein the core dope comprises a first polymer, a first solvent, and a plurality of nanoparticles, and
wherein the sheath dope comprises a second polymer and a second solvent, wherein the second polymer is a thermally rearrangable polymer; and
b. heating the multilayer hollow fiber membrane precursor at a temperature of between about 270° C. and about 450° C. for a period of about 1 to 4 hours to form an asymmetric composite thermally rearranged hollow fiber membrane.

### Claim 13 (depends on 12)

The process of claim 12, wherein the thermally rearrangable polymer is selected from the group consisting of polybenzoxazoles, polybenzothiazoles, polybenzimidazoles, and combinations.

### Claim 14

An asymmetric multilayer CMS hollow fiber membrane comprising
a. a core layer comprising a pyrolyzed first polymer and a plurality of nanoparticles, wherein the core layer has a substantially annular cross-section; and
b. a sheath layer comprising a pyrolyzed second polymer, wherein the sheath layer has a substantially annular cross-section and is adjacent to and radially outward from the core layer.

### Claim 15 (depends on 14)

The asymmetric multilayer CMS hollow fiber membrane of claim 14,
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a gas permeance at least 300% greater than a gas permeance of an otherwise equivalent asymmetric multilayer CMS hollow fiber membrane that does not include nanoparticles in the core layer; or
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a selectivity that is at least 85% of the selectivity of an otherwise equivalent asymmetric multilayer CMS hollow fiber membrane that that does not include nanoparticles in a core layer.

### Claim 16 (depends on 14)

The asymmetric multilayer CMS hollow fiber membrane of claim 14,
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a CO2 permeance of at least 50 GPU and a CO2/CH4 selectivity of at least 60 when subjected to a mixed feed containing 50 mol % CO2 and 50 mol % CH4 at 150 psi and 35° C.; or
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a O2 permeance of at least 80 GPU and a O2/N2 selectivity of at least 9 when subjected to a single gas feed at 50 psi and 70° C.; or
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a C2H4 permeance of at least 5 GPU and a C2H4/C2H6 selectivity of at least 4 when subjected to a single gas feed at 100 psi and 35° C.; or
wherein the asymmetric multilayer CMS hollow fiber membrane comprises a C3H8 permeance of at least 5 GPU and a C3H6/C3H8 selectivity of at least 20 when subjected to a mixed feed containing 50 mol % C3H6 and 50 mol % C3H8 at 100 psi and 35° C.

### Claim 17 (depends on 14)

A process for separating a mixture of at least two gases comprising contacting the mixture of gases with the asymmetric multilayer CMS hollow fiber membrane of claim 14 to separate the mixture into a permeate stream that is enriched in a first gas and a retentate stream that is enriched in a second gas.

### Claim 18 (depends on 17)

The process of claim 17, wherein the mixture of at least two gases comprises CO2 and CH4; H2S and CH4; CO2, H2S, and CH4; CO2 and N2; O2 and N2; N2 and CH4; He and CH4; H2 and CH4; H2 and C2H4; ethylene and ethane; propylene and propane; or ethane/propane and ethylene/propylene.

### Claim 19 (depends on 17)

The process of claim 17, wherein the mixture of at least two gases comprises acid gases and natural gases.

### Claim 20 (depends on 17)

The process of claim 17, wherein the mixture of at least two gases comprises CO2 and at least one hydrocarbon, and wherein the permeate stream is enriched in CO2.