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公开(公告)号：US11517857B2
公开(公告)日：2022-12-06
申请号：US16634401
申请日：2018-03-20
Applicant: Dow Global Technologies LLC
Inventor： Liren Xu , Rahul Sharma , Thomas Fitzgibbons , Mark K. Brayden , Marcos V. Martinez
Abstract: A method of making a hollow fiber carbon molecular sieve is comprised of heating a hollow polymer fiber to a carbonization temperature in an atmosphere that is non-oxidizing to form a hollow fiber carbon molecular sieve, wherein during at least a portion of the heating a tensile force is applied to the hollow polymer fiber. The method may improve the separation of gases similar in size such a propylene from propane.
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公开(公告)号：US11420154B2
公开(公告)日：2022-08-23
申请号：US17051620
申请日：2019-04-03
Inventor： Justin T. Vaughn , Wulin Qiu , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: The invention is an improved method of making an improved carbon molecular sieve (CMS) membrane in which a precursor polymer (e.g., polyimide) is pyrolyzed at a pyrolysis temperature to form a CMS membrane that is cooled to ambient temperature (about 40° C. or 30° C. to about 20° C.). The CMS membrane is then reheated to a reheating temperature less than the pyrolysis temperature to form the improved CMS membrane. The improved CMS membranes have shown an improved combination of selectivity and permeance as well as stability for separating hydrogen from gas molecules (e.g., methane, ethane, propane, ethylene, propylene, butane, carbon dioxide, nitrogen, butylene, and combinations thereof).
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公开(公告)号：US20190275471A1
公开(公告)日：2019-09-12
申请号：US16333919
申请日：2017-09-25
Applicant: Dow Global Technologies LLC
Inventor： Liren Xu , Rahul Sharma , William J. Harris , Mark K. Brayden , Marcos V. Martinez
Abstract: An asymmetric hollow fiber (CMS) carbon molecular sieve is made by providing a dope solution comprised of a polvimide and a solvent, at a temperature greater than 250° C. that is less than the storage modulus at a temperature of 250° C., but no more than ten times less as measured using dynamic mechanical thermal analysis from 250° C. to a temperature where the polyimide carbonizes. The polvimide is shaped into a hollow polvimide fiber, the solvent removed and the polyimide hollow fiber is heated to pyroiyze the polvimide and form the asymmetric hollow carbon molecular sieve. The asymmetric hollow fiber carbon molecular sieve has a wall that is defined by an inner surface and outer surface of said fiber and the wall has an inner porous support region extending from the inner surface to an outer raicroporous separation region that extends from the inner porous support region to the outer surface. Surprisingly, when the polyimide has the particular storage modulus characteristics, the method allows for the hollow fiber CMS to be made without any pre-treatmenis or additives to inhibit stractural collapse of the inner microporous region.
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公开(公告)号：US20230088542A1
公开(公告)日：2023-03-23
申请号：US17974786
申请日：2022-10-27
Inventor： Yu-Han Chu , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a group 13 metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a group 13 metal incorporated into it, wherein the metal is in a reduced state. The pyrolyzing for the precursor having the group 13 metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal in a reduced state (e.g., covalently bonded to carbon or nitrogen or in the metal state).
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公开(公告)号：US20210229030A1
公开(公告)日：2021-07-29
申请号：US17051620
申请日：2019-04-03
Inventor： Justin T. Vaughn , Wulin Qiu , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: The invention is an improved method of making an improved carbon molecular sieve (CMS) membrane in which a precursor polymer (e.g., polyimide) is pyrolyzed at a pyrolysis temperature to form a CMS membrane that is cooled to ambient temperature (about 40° C. or 30° C. to about 20° C.). The CMS membrane is then reheated to a reheating temperature less than the pyrolysis temperature to form the improved CMS membrane. The improved CMS membranes have shown an improved combination of selectivity and permeance as well as stability for separating hydrogen from gas molecules (e.g., methane, ethane, propane, ethylene, propylene, butane, carbon dioxide, nitrogen, butylene, and combinations thereof).
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Patent Agency Ranking
公开(公告)号：US20190099722A1
公开(公告)日：2019-04-04
申请号：US16086621
申请日：2017-03-02
Inventor： John Hessler , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: The invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a polyimide precursor polymer is pyrolyzed to form a carbon molecular sieve membrane by heating, in a furnace, said polyimide precursor polymer to a final pyrolysis temperature of 600 C to 700 C at a pyrolysis heating rate of 3 to 7 C/minute from 400 C to the final pyrolysis temperature, the final pyrolysis temperature being held for a pyrolysis time of at most 60 minutes in a non-oxidizing atmosphere. In a particular embodiment, the cooling rate from the pyrolysis temperature is accelerated by methods to remove heat. The CMS membranes have shown an improved combination of selectivity and permeance as well as being particularly suitable to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.
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公开(公告)号：US11504675B2
公开(公告)日：2022-11-22
申请号：US16758114
申请日：2018-06-08
Inventor： Yu-Han Chu , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a group 13 metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a group 13 metal incorporated into it, wherein the metal is in a reduced state. The pyrolyzing for the precursor having the group 13 metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal in a reduced state (e.g., covalently bonded to carbon or nitrogen or in the metal state).
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8.发明申请公开(公告)号：US20210324142A1
公开(公告)日：2021-10-21
申请号：US17266778
申请日：2019-08-20
Inventor： Justin T. Vaughn , Wulin Qiu , William J. Koros , Liren Xu , Mark K. Brayden
Abstract: A cross-linked polyimide of the reaction product of a crosslinking agent and a polyimide. The cross-linking agent having at least two cross-linking moieties and the polyimide has a plurality of polyimide chains having an aryl constituent with a moiety comprised of a reactive substituent. The polyimide has crosslinks from the reaction of the reactive substituent of the aryl constituents of the polyimide chains and the cross-linking moieties of the cross-linking agent. The cross-linking may be induced by thermally treating a mixture of the polyimide and crosslinking agent above about 150° C. to a temperature where the polyimide begins to decompose under an inert atmosphere. The membrane can be used for separations involving gases such as hydrogen and light hydrocarbons.
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公开(公告)号：US20210129085A1
公开(公告)日：2021-05-06
申请号：US17051571
申请日：2019-04-03
Inventor： Liren Xu , Thomas Fitzgibbons , Mark K. Brayden , Marcos V. Martinez , William J. Koros , Wulin Qiu
Abstract: The invention is an improved method of making an improved carbon molecular sieve (CMS) membrane in which a precursor polymer (e.g., polyimide) is pyrolyzed at a pyrolysis temperature to form a CMS membrane that is cooled to ambient temperature (about 40° C. or 30° C. to about 20° C.). The CMS membrane is then reheated to a reheating temperature of at least 250° C. to 400° C. to form the improved CMS membrane. The CMS have a novel microstructure as determined by Raman spectroscopy. The improved CMS membranes have shown an improved combination of selectivity and permeance as well as stability for separating light hydrocarbon gas molecules such as C1 to C6 hydrocarbon gases (e.g., methane, ethane, propane, ethylene, propylene, butane, butylene).
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公开(公告)号：US20190118133A1
公开(公告)日：2019-04-25
申请号：US16096928
申请日：2017-04-25
Inventor： Yu-Han Chu , William J. Koros , Liren Xu , Mark K. Brayden , Marcos V. Martinez
Abstract: A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a transition metal, wherein the transition metal is one or more of a group 4-10 and 12 transition metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a transition metal incorporated into it. The pyrolyzing for the precursor having the transition metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal has a valence greater than zero (i.e., not metal bonded) to a valence desirably closer to its maximum valence.
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