Patents by Inventor Gowri Krishnamurthy

Gowri Krishnamurthy 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: 10767922
    Abstract: A method and apparatus for liquefying a natural gas feed stream and removing nitrogen therefrom to produce a nitrogen-depleted LNG product, in which a natural gas feed stream is fed into the warm end of a main heat exchanger, cooled and at least partially liquefied, withdrawn from an intermediate location of the main heat exchanger and separated to form a nitrogen-enriched natural gas vapor stream and a nitrogen-depleted natural gas liquid stream, the liquid and vapor streams being reintroduced into an intermediate location of the main heat exchanger and further cooled in parallel to form a first LNG stream and a first at least partially liquefied nitrogen-enriched natural gas stream, respectively.
    Type: Grant
    Filed: June 19, 2017
    Date of Patent: September 8, 2020
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Fei Chen, Yang Liu, Gowri Krishnamurthy, Christopher Michael Ott, Mark Julian Roberts
  • Patent number: 10753676
    Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.
    Type: Grant
    Filed: September 28, 2017
    Date of Patent: August 25, 2020
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts, Adam Adrian Brostow
  • Publication number: 20200217585
    Abstract: A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.
    Type: Application
    Filed: March 23, 2020
    Publication date: July 9, 2020
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 10663220
    Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. Optionally additional precooling heat exchangers, and/or phase separators may be used.
    Type: Grant
    Filed: October 7, 2016
    Date of Patent: May 26, 2020
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 10544986
    Abstract: A system and method is provided for increasing the capacity and efficiency of natural gas liquefaction processes by debottlenecking the refrigerant compression system. A secondary compression circuit comprising at least one double flow compressor is provided in parallel fluid flow communication with at least a portion of a primary compression circuit.
    Type: Grant
    Filed: March 29, 2017
    Date of Patent: January 28, 2020
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20190331414
    Abstract: Described herein are methods and systems for the liquefaction of a natural gas feed stream using a refrigerant comprising methane. The methods and systems use a refrigeration circuit and cycle that employs two or more turbo-expanders to expand two or more streams of gaseous refrigerant down to different pressures to provide cold streams of at least predominantly gaseous refrigerant at different pressures that are used to provide refrigeration for precooling and liquefying the natural gas. The resulting liquefied natural gas stream is then flashed to produce an LNG product and a flash gas, the flash gas being recycled to the natural gas feed stream.
    Type: Application
    Filed: April 27, 2018
    Publication date: October 31, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20190331413
    Abstract: Described herein are methods and systems for the liquefaction of a natural gas stream using a refrigerant comprising methane or a mixture of methane and nitrogen. The methods and systems use a refrigeration circuit and cycle that employs one or more turbo-expanders to expand one or more streams of gaseous refrigerant to provide one or more streams of at least predominantly gaseous refrigerant that are used to provide refrigeration for liquefying and/or precooling the natural gas, and a J-T valve to expand down to a lower pressure a stream of liquid or two-phase refrigerant to provide a vaporizing stream of refrigerant that provides refrigeration for sub-cooling.
    Type: Application
    Filed: April 27, 2018
    Publication date: October 31, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 10323880
    Abstract: The present invention relates to methods of increasing the operability, capacity, and efficiency of natural gas liquefaction processes, with a focus on mixed refrigerant cycles. The present invention also relates to natural gas liquefaction systems in which the above-mentioned methods can be carried out. More specifically, a refrigerant used in a pre-cooling heat exchanger of a natural gas liquefaction plant is withdrawn from the pre-cooling heat exchanger, separated into liquid and vapor streams in a liquid-vapor separator after being cooled and compressed. The vapor portion is further compressed, cooled, and fully condensed, then returned to the liquid-vapor separator. Optionally, the fully condensed stream may be circulated through a heat exchanger before being returned to the liquid-vapor separator for the purpose of cooling other streams, including the liquid stream from the liquid-vapor separator.
    Type: Grant
    Filed: September 27, 2016
    Date of Patent: June 18, 2019
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Mark Julian Roberts, Gowri Krishnamurthy, Adam Adrian Brostow
  • Publication number: 20190162468
    Abstract: A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.
    Type: Application
    Filed: December 4, 2017
    Publication date: May 30, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20190162469
    Abstract: A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.
    Type: Application
    Filed: December 4, 2017
    Publication date: May 30, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20190093947
    Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.
    Type: Application
    Filed: September 28, 2017
    Publication date: March 28, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts, Adam Adrian Brostow
  • Publication number: 20190093946
    Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.
    Type: Application
    Filed: September 28, 2017
    Publication date: March 28, 2019
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts, Adam Adrian Brostow
  • Patent number: 10180282
    Abstract: A system and method for increasing the capacity and efficiency of natural gas liquefaction processes by debottlenecking the refrigerant compression system. A secondary compression circuit comprising at least one positive displacement compressor is provided in parallel fluid flow communication with at least a portion of a primary compression circuit comprising at least one dynamic compressor.
    Type: Grant
    Filed: September 30, 2015
    Date of Patent: January 15, 2019
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy
  • Publication number: 20180283774
    Abstract: A system and method is provided for increasing the capacity and efficiency of natural gas liquefaction processes by debottlenecking the refrigerant compression system. A secondary compression circuit comprising at least one double flow compressor is provided in parallel fluid flow communication with at least a portion of a primary compression circuit.
    Type: Application
    Filed: March 29, 2017
    Publication date: October 4, 2018
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 9945604
    Abstract: A method for liquefying a natural gas feed stream and removing nitrogen therefrom, the method comprising passing a natural gas feed stream through a main heat exchanger to produce a first LNG stream, and separating a liquefied or partially liquefied natural gas stream in a distillation column to form nitrogen-rich vapor product, wherein a closed loop refrigeration system provides refrigeration to the main heat exchanger and to a condenser heat exchanger that provides reflux to the distillation column.
    Type: Grant
    Filed: April 24, 2014
    Date of Patent: April 17, 2018
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Christopher Michael Ott, Gowri Krishnamurthy, Fei Chen, Yang Liu, Mark Julian Roberts
  • Publication number: 20180100694
    Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprisingcooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. Optionally additional precooling heat exchangers, and/or phase separators may be used.
    Type: Application
    Filed: October 7, 2016
    Publication date: April 12, 2018
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20180087832
    Abstract: The present invention relates to methods of increasing the operability, capacity, and efficiency of natural gas liquefaction processes, with a focus on mixed refrigerant cycles. The present invention also relates to natural gas liquefaction systems in which the above-mentioned methods can be carried out. More specifically, a refrigerant used in a pre-cooling heat exchanger of a natural gas liquefaction plant is withdrawn from the pre-cooling heat exchanger, separated into liquid and vapor streams in a liquid-vapor separator after being cooled and compressed. The vapor portion is further compressed, cooled, and fully condensed, then returned to the liquid-vapor separator. Optionally, the fully condensed stream may be circulated through a heat exchanger before being returned to the liquid-vapor separator for the purpose of cooling other streams, including the liquid stream from the liquid-vapor separator.
    Type: Application
    Filed: September 27, 2016
    Publication date: March 29, 2018
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Mark Julian Roberts, Gowri Krishnamurthy, Adam Adrian Brostow
  • Patent number: 9920987
    Abstract: A system and method of gas liquefaction having a compression sequence for a mixed refrigerant in which a mixing column is used to provide liquid and vapor product streams at least one step of the compression sequence in which a phase separation is desirable. In addition, the compression sequence may optionally or alternatively use a stripper column in at least one step in the compression sequence in which a phase separation is desirable.
    Type: Grant
    Filed: May 8, 2015
    Date of Patent: March 20, 2018
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Adam Adrian Brostow, Gowri Krishnamurthy
  • Publication number: 20180058752
    Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.
    Type: Application
    Filed: August 8, 2017
    Publication date: March 1, 2018
    Applicant: AIR PRODUCTS AND CHEMICALS, INC.
    Inventors: Brian Keith Johnston, Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 9816754
    Abstract: A method and apparatus for liquefying a natural gas feed stream and removing nitrogen therefrom to produce a nitrogen-depleted LNG product, in which a natural gas feed stream is passed through main heat exchanger to produce a first LNG stream, which is separated to form a nitrogen-depleted LNG product and a recycle stream composed of nitrogen-enriched natural gas vapor, and in which the recycle stream is passed through main heat exchanger to produce a first LNG stream, separately from and in parallel with the natural gas feed stream, to produce a first at least partially liquefied nitrogen-enriched natural gas stream that is separated to provide a nitrogen-rich vapor product.
    Type: Grant
    Filed: April 24, 2014
    Date of Patent: November 14, 2017
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Fei Chen, Yang Liu, Gowri Krishnamurthy, Christopher Michael Ott, Mark Julian Roberts