Patents by Inventor Liren Xu

Liren Xu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11167248
    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.
    Type: Grant
    Filed: September 25, 2017
    Date of Patent: November 9, 2021
    Assignee: Dow Global Technologies LLC
    Inventors: Liren Xu, Rahul Sharma, William J. Harris, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20210324142
    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.
    Type: Application
    Filed: August 20, 2019
    Publication date: October 21, 2021
    Applicants: Dow Global Technologies LLC, Georgia Tech Research Corporation
    Inventors: Justin T. Vaughn, Wulin Qiu, William J. Koros, Liren Xu, Mark K. Brayden
  • Patent number: 11130098
    Abstract: The invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a precursor polymer is pyrolyzed to form a carbon molecular sieve membrane that is then exposed to a conditioning atmosphere comprised of a target permeate gas molecule such as ethylene when the membrane is desired to separate it from a light hydrocarbon gas stream. The exposure to the ethylene desirably occurs prior to the CMS permeance and selectivity combination substantially changing (e.g., within 5 days) of cooling from the pyrolyzing temperature. The CMS membranes have shown an improved combination of selectivity and permeance as well as stability and are useful to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.
    Type: Grant
    Filed: November 30, 2016
    Date of Patent: September 28, 2021
    Assignee: Dow Global Technologies LLC
    Inventors: John Hessler, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Patent number: 11084000
    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.
    Type: Grant
    Filed: March 2, 2017
    Date of Patent: August 10, 2021
    Assignees: Dow Global Technologies LLC, Georgia Tech Research Corporation
    Inventors: John Hessler, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20210229030
    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).
    Type: Application
    Filed: April 3, 2019
    Publication date: July 29, 2021
    Applicants: Dow Global Technologies LLC, Georgia Tech Research Corporation
    Inventors: Justin T. Vaughn, Wulin Qiu, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20210129085
    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).
    Type: Application
    Filed: April 3, 2019
    Publication date: May 6, 2021
    Applicants: Dow Global Technologies LLC, Georgia Tech Research Corporation
    Inventors: Liren Xu, Thomas Fitzgibbons, Mark K. Brayden, Marcos V. Martinez, William J. Koros, Wulin Qiu
  • Patent number: 10924331
    Abstract: A controller area network (CAN) communication system is provided. The CAN communication system comprises: a CAN bus; at least one electronic control unit (ECU) coupled to the CAN bus; a host module coupled to the CAN bus for controlling the operation of the at least one ECU. The host module comprises: a controller; and at least two adapters coupled between the CAN bus and the controller for communication therebetween. The controller is configured to monitor a communication between a first adapter of the at least two adapters and the CAN bus by a second adapter of the at least two adapters when the controller is communicating with the CAN bus through the first adapter, and to switch its communication with the CAN bus from through the first adapter to through the second adapter when a failure of the communication between the first adapter and the CAN bus is determined.
    Type: Grant
    Filed: January 4, 2019
    Date of Patent: February 16, 2021
    Assignee: WeRide Corp.
    Inventors: Kun Huang, Liren Xu
  • Publication number: 20210003710
    Abstract: An image capturing method, comprising: scanning with a light detection and ranging (LIDAR) sensor an environment of the LIDAR sensor, wherein the LIDAR sensor progressively rotates about a rotation axis at a step angle, and when scanning each step angle the LIDAR sensor generates a point cloud of a portion of the environment in a predetermined pattern; scanning with an image sensor assembly mechanically coupled to the LIDAR sensor the environment in synchronization with the scanning by the LIDAR sensor to generate on an imaging plane of the image sensor assembly a sequence of image pixel rows of a portion of the environment corresponding to the point cloud of the portion of the environment; and combining the point cloud with the sequence of image pixel rows for the scanning of each step angle to obtain a fused image of the portion of the environment.
    Type: Application
    Filed: July 6, 2020
    Publication date: January 7, 2021
    Inventors: Junhua TAN, Fengzhi WU, Liren XU, Renfeng ZUO, Kerry SHU, Junping XIE, Yin-Min HUANG
  • Publication number: 20200276542
    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).
    Type: Application
    Filed: June 8, 2018
    Publication date: September 3, 2020
    Applicants: Dow Global Technologies LLC, Georgia Tech Research Corporation
    Inventors: Yu-Han Chu, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20200254393
    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.
    Type: Application
    Filed: March 20, 2018
    Publication date: August 13, 2020
    Applicant: Dow Global Technologies LLC
    Inventors: Liren Xu, Rahul Sharma, Thomas Fitzgibbons, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20200114316
    Abstract: An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained.
    Type: Application
    Filed: March 14, 2018
    Publication date: April 16, 2020
    Applicant: Dow Global Technologies LLC
    Inventors: Junqiang Liu, Liren Xu, Troy D. Wolford
  • Publication number: 20190275471
    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.
    Type: Application
    Filed: September 25, 2017
    Publication date: September 12, 2019
    Inventors: Liren Xu, Rahul Sharma, William J. Harris, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20190247806
    Abstract: A polyimide separation membrane is comprised of a polyimide, a halogen compound (e.g., halogenated aromatic epoxide) that is soluble in the polyimide and a hydrocarbon having 2 to 5 carbons (e.g., ethane, ethylene, propane or propylene). The gas separation membrane has improved selectivity for small gas molecules such as hydrogen compared to polyimide membrane not containing the halogen compound or hydrocarbon. The polyimide separation membrane may be made by shaping a dope solution comprised of a polyimide, a halogen containing compound that is soluble in the polyimide, removing the solvent and then exposing the untreated polyimide membrane to a treating atmosphere comprising a hydrocarbon having 2 to 5 carbons for a sufficient time to form the polyimide membrane.
    Type: Application
    Filed: September 25, 2017
    Publication date: August 15, 2019
    Inventors: Liren Xu, Justin T. Vaughn, Wulin Qiu, William J. Koros, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20190215233
    Abstract: A controller area network (CAN) communication system is provided. The CAN communication system comprises: a CAN bus; at least one electronic control unit (ECU) coupled to the CAN bus; a host module coupled to the CAN bus for controlling the operation of the at least one ECU. The host module comprises: a controller; and at least two adapters coupled between the CAN bus and the controller for communication therebetween. The controller is configured to monitor a communication between a first adapter of the at least two adapters and the CAN bus by a second adapter of the at least two adapters when the controller is communicating with the CAN bus through the first adapter, and to switch its communication with the CAN bus from through the first adapter to through the second adapter when a failure of the communication between the first adapter and the CAN bus is determined.
    Type: Application
    Filed: January 4, 2019
    Publication date: July 11, 2019
    Inventors: Kun HUANG, Liren XU
  • Publication number: 20190118133
    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.
    Type: Application
    Filed: April 25, 2017
    Publication date: April 25, 2019
    Inventors: Yu-Han Chu, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20190099722
    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.
    Type: Application
    Filed: March 2, 2017
    Publication date: April 4, 2019
    Inventors: John Hessler, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Publication number: 20180369761
    Abstract: The invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a precursor polymer is pyrolyzed to form a carbon molecular sieve membrane that is then exposed to a conditioning atmosphere comprised of a target permeate gas molecule such as ethylene when the membrane is desired to separate it from a light hydrocarbon gas stream. The exposure to the ethylene desirably occurs prior to the CMS permeance and selectivity combination substantially changing (e.g., within 5 days) of cooling from the pyrolyzing temperature. The CMS membranes have shown an improved combination of selectivity and permeance as well as stability and are useful to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.
    Type: Application
    Filed: November 30, 2016
    Publication date: December 27, 2018
    Inventors: John Hessler, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
  • Patent number: 10150840
    Abstract: Prepare a carbon molecular sieve membrane from a polyimide (e.g., a 6FDA/BPDA-DAM polyimide) that has a glass transition temperature of at least 400° C. and includes a bridged phenyl compound for separation of hydrogen and ethylene from one another whether present as a pure mixture of hydrogen and ethylene or as components of a cracked gas. Preparation comprises two sequential steps a) and b). In step a), place a membrane fabricated from defect-free fibers of the polyimide in contact with an oxygen-containing atmosphere under conditions of time and temperature sufficient to produce a pre-oxidized and pre-carbonized polymeric membrane that is insoluble in hot (110 C) n-methylpyrolidone and at least substantially free of substructure collapse.
    Type: Grant
    Filed: September 3, 2015
    Date of Patent: December 11, 2018
    Assignee: Dow Global Technologies LLC
    Inventor: Liren Xu
  • Publication number: 20170247512
    Abstract: Prepare a carbon molecular sieve membrane from a polyimide (e.g., a 6FDA/BPDA-DAM polyimide) that has a glass transition temperature of at least 400° C. and includes a bridged phenyl compound for separation of hydrogen and ethylene from one another whether present as a pure mixture of hydrogen and ethylene or as components of a cracked gas. Preparation comprises two sequential steps a) and b). In step a), place a membrane fabricated from defect-free fibers of the polyimide in contact with an oxygen-containing atmosphere under conditions of time and temperature sufficient to produce a pre-oxidized and pre-carbonized polymeric membrane that is insoluble in hot (110 C) n-methylpyrolidone and at least substantially free of substructure collapse.
    Type: Application
    Filed: September 3, 2015
    Publication date: August 31, 2017
    Inventor: Liren Xu
  • Patent number: D928641
    Type: Grant
    Filed: May 21, 2019
    Date of Patent: August 24, 2021
    Assignee: WERIDE CORP.
    Inventors: Juanjuan Sun, Liren Xu, Cheng-fu Hsieh, Wei Gu