US 11,931,697 B2
Separation of gases via carbonized vinylidene chloride copolymer gas separation membranes and processes therefor
Junqiang Liu, Manvel, TX (US); Douglas E. Beyer, Midland, MI (US); Janet M. Goss, Saginaw, MI (US); Chan Han, Midland, MI (US); and Edward M. Calverley, Midland, MI (US)
Assigned to Dow Global Technologies LLC, Midland, MI (US)
Filed by Dow Global Technologies LLC, Midland, MI (US)
Filed on Apr. 15, 2021, as Appl. No. 17/231,358.
Application 17/231,358 is a division of application No. 16/085,038, granted, now 11,007,488, previously published as PCT/US2017/022275, filed on Mar. 14, 2017.
Claims priority of provisional application 62/308,899, filed on Mar. 16, 2016.
Prior Publication US 2021/0229045 A1, Jul. 29, 2021
Int. Cl. B01D 69/02 (2006.01); B01D 53/22 (2006.01); B01D 67/00 (2006.01); B01D 71/02 (2006.01); B01D 71/30 (2006.01); B01D 71/80 (2006.01); B01D 69/08 (2006.01); B01D 71/40 (2006.01); B01D 71/42 (2006.01)
CPC B01D 69/02 (2013.01) [B01D 53/228 (2013.01); B01D 67/0067 (2013.01); B01D 71/021 (2013.01); B01D 71/028 (2013.01); B01D 71/30 (2013.01); B01D 71/80 (2013.01); B01D 67/002 (2013.01); B01D 69/08 (2013.01); B01D 71/40 (2013.01); B01D 71/42 (2013.01); B01D 2256/10 (2013.01); B01D 2256/20 (2013.01); B01D 2256/22 (2013.01); B01D 2256/245 (2013.01); B01D 2257/108 (2013.01); B01D 2325/022 (2013.01); B01D 2325/04 (2013.01); B01D 2325/20 (2013.01)] 8 Claims
 
1. A method of making a carbonized polyvinylidene chloride copolymer film or a carbonized hollow fiber, the method comprising,
(a) providing a polyvinylidene chloride copolymer film having a thickness of 1 micrometer to 250 micrometers or a hollow fiber having a diameter of 1 micrometer to 250 micrometers,
(b) heating the polyvinylidene chloride copolymer film or the hollow fiber to a pretreatment temperature of 100° C. to 180° C. to form a pretreated polyvinylidene chloride copolymer film or a pretreated hollow fiber while restraining the polyvinylidene chloride copolymer film or the hollow fiber, and
(c) heating the pretreated polyvinylidene chloride copolymer film or the pretreated hollow fiber to a maximum pyrolysis temperature from 350° C. to 750° C. to produce the carbonized polyvinylidene chloride copolymer or the carbonized hollow fiber while restraining the pretreated polyvinylidene chloride copolymer film or the pretreated hollow fiber,
wherein the restraining of steps (b) and (c) is conducted by applying a compressive force,
wherein the carbonized polyvinylidene chloride copolymer film or the carbonized hollow fiber has an average pore size greater than a diameter of a large gas molecule larger than hydrogen gas determined by gas adsorption employing gas probe molecules of differing sizes, and
wherein the carbonized polyvinylidene chloride copolymer film or the carbonized hollow fiber has a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 Gas Permeation Unit (GPU) hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity.