Methods for preparing microcapillary carbon molecular sieve membranes

Patent metadata

Field	Value
Publication number	US-12458931-B2
Application number	US-202017788594-A
Country	US
Kind code	B2
Filing date	Dec 16, 2020
Priority date	Dec 27, 2019
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

A process for preparing a microcapillary carbon molecular sieve membrane may include extruding a polyvinylidene chloride polymer to a thickness from 10 μm to 1,000 μm to form an extruded polymeric microcapillary film, wherein the extruded polymeric microcapillary film comprises a first end, a second end, and one or more microcapillaries extending from the first end to the second end; pre-treating the extruded polymeric microcapillary film at a temperature from 100° C. to 200° C. for a time from 1 hour to 48 hours to form a pre-treated polymeric microcapillary film; and pyrolizing the pre-treated polymeric microcapillary film at a temperature from 200° C. to 1,500° C. for a time from 15 minutes to 5 hours to form the microcapillary carbon molecular sieve membrane.

First claim

The invention claimed is:

1 . A process for preparing a microcapillary carbon molecular sieve membrane, the process comprising:
extruding a polyvinylidene chloride (PVDC) polymer to a thickness from 10 μm to 1,000 μm to form an extruded polymeric microcapillary film, wherein the extruded polymeric microcapillary film comprises a first end, a second end, and two or more microcapillaries extending from the first end to the second end; pre-treating the extruded polymeric microcapillary film at a temperature from 100° C. to 200° C. for a time from 1 hour to 48 hours to form a pre-treated polymeric microcapillary film; and pyrolizing the pre-treated polymeric microcapillary film at a temperature from 200° C. to 1,500° C. for a time from 15 minutes to 5 hours to form the microcapillary carbon molecular sieve membrane, wherein
the microcapillary carbon molecular sieve membrane comprises micropores having an average micropore size from 3 Å to 5 Å, and
the one or more microcapillaries each have a diameter from 1 μm to 500 μm.

2 . The process of claim 1 , wherein the extruding step comprises melting the PVDC polymer and extruding the PVDC polymer through a single-screw extruder and a microcapillary film die to form the extruded polymeric microcapillary film.

3 . The process of claim 1 , wherein the extruding step is performed at a temperature from 125° C. to 225° C.

4 . The process of any one of claim 1 , wherein the pre-treating step comprises placing the extruded polymeric microcapillary film between ceramic plates and inserting the extruded polymeric microcapillary film into an oven.

5 . The process of claim 4 , further comprising placing a layer of anti-adhesive material between the extruded polymeric microcapillary film and the ceramic plates.

6 . The process of claim 1 , further comprising increasing the temperature during the pre-treating step by at least 1° C./min for at least 15 minutes.

7 . The process of claim 1 , wherein the pre-treating step further comprises subjecting the extruded polymeric microcapillary film to gamma beam irradiation, electron beam irradiation, UV irradiation, or combinations thereof.

8 . The process of claim 1 , wherein the pyrolizing step comprises placing the extruded polymeric microcapillary film between ceramic plates and passing the extruded polymeric microcapillary film into an oven.

9 . The process of claim 8 , further comprising placing a layer of anti-adhesive material between the extruded polymeric microcapillary film and the ceramic plates.

10 . The process of claim 1 , wherein the pyrolizing step is performed at a temperature from 500° C. to 900° C.

11 . The process of claim 1 , further comprising increasing the temperature during the pyrolizing step by at least 3° C./min for at least 15 minutes.

12 . The process of claim 1 , wherein the pyrolizing step is performed in a reduced environment, in which the environment is continually purged with nitrogen from 2.5 L/min to 7.5 L/min.

13 . The process of claim 1 , wherein the temperature of the pyrolizing step is inversely proportional to the average micropore sizes in the microcapillary film wall.

14 . The process of claim 1 , wherein the one or more microcapillaries each comprise a microcapillary fluid.

15 . The process of claim 14 , wherein the microcapillary fluid comprises oxygen, nitrogen, carbon dioxide, argon, helium, or combinations thereof.

16 . The process of claim 1 , wherein the microcapillary carbon molecular sieve membrane is a sheet membrane.

17 . The process of claim 1 , wherein:
the microcapillary carbon molecular sieve membrane has a flat shape; and the first end and the second end each have a generally rectangular shape.

18 . A process for preparing a microcapillary carbon molecular sieve membrane, the process comprising:
extruding a polyvinylidene chloride (PVDC) polymer to a thickness from 10 μm to 1,000 μm to form an extruded polymeric microcapillary film, wherein the extruded polymeric microcapillary film comprises a first end, a second end, and one or more microcapillaries extending from the first end to the second end; pre-treating the extruded polymeric microcapillary film at a temperature from 100° C. to 200° C. for a time from 1 hour to 48 hours to form a pre-treated polymeric microcapillary film; and pyrolizing the pre-treated polymeric microcapillary film at a temperature from 200° C. to 1,500° C. for a time from 15 minutes to 5 hours to form the microcapillary carbon molecular sieve membrane, wherein
the microcapillary carbon molecular sieve membrane comprises micropores having an average micropore size from 3 Å to 5 Å,
the one or more microcapillaries each have a diameter from 1 μm to 500 μm, and
the microcapillary carbon molecular sieve membrane is a sheet membrane.

19 . A process for preparing a microcapillary carbon molecular sieve membrane, the process comprising:
extruding a polyvinylidene chloride (PVDC) polymer to a thickness from 10 μm to 1,000 μm to form an extruded polymeric microcapillary film, wherein the extruded polymeric microcapillary film comprises a first end having a generally rectangular shape, a second end having a generally rectangular shape, and one or more microcapillaries extending from the first end to the second end; pre-treating the extruded polymeric microcapillary film at a temperature from 100° C. to 200° C. for a time from 1 hour to 48 hours to form a pre-treated polymeric microcapillary film; and pyrolizing the pre-treated polymeric microcapillary film at a temperature from 200° C. to 1,500° C. for a time from 15 minutes to 5 hours to form the microcapillary carbon molecular sieve membrane having a flat shape, wherein
the microcapillary carbon molecular sieve membrane comprises micropores having an average micropore size from 3 Å to 5 Å, and
the one or more microcapillaries each have a diameter from 1 μm to 500 μm.

Assignees

• Dow Global Technologies Llc

Inventors

• Liu Junqiang
• Koppi Kurt A
• Millar Dean M

Classifications

• B01D2323/082

  Cooling · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D67/0067

  by carbonisation or pyrolysis · CPC title

• B01D63/066 Primary

  with a porous block having membrane coated passages · CPC title

• B01D2323/34

  Use of radiation · CPC title