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).
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Publication number: 20190331413Abstract: 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: ApplicationFiled: April 27, 2018Publication date: October 31, 2019Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts
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Patent number: 10323880Abstract: 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 More specifically, a refrigerant used in a pre-cooling heat exchanger of a natural gas liquefaction plant is withdrawn from the pre-cooling heat exchanger, separated into liquid and vapor streams in a liquid-vapor separator after being cooled and compressed.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: GrantFiled: September 27, 2016Date of Patent: June 18, 2019Assignee: Air Products and Chemicals, Inc.Inventors: Mark Julian Roberts, Gowri Krishnamurthy, Adam Adrian Brostow
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Publication number: 20190162468Abstract: 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: ApplicationFiled: December 4, 2017Publication date: May 30, 2019Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts
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Publication number: 20190162469Abstract: 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: ApplicationFiled: December 4, 2017Publication date: May 30, 2019Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts
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Publication number: 20190093947Abstract: 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: ApplicationFiled: September 28, 2017Publication date: March 28, 2019Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts, Adam Adrian Brostow
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Publication number: 20190093946Abstract: 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: ApplicationFiled: September 28, 2017Publication date: March 28, 2019Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts, Adam Adrian Brostow
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Patent number: 10180282Abstract: 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: GrantFiled: September 30, 2015Date of Patent: January 15, 2019Assignee: Air Products and Chemicals, Inc.Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy
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Publication number: 20180283774Abstract: 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: ApplicationFiled: March 29, 2017Publication date: October 4, 2018Applicant: Air Products and Chemicals, Inc.Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy, Mark Julian Roberts
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Patent number: 9945604Abstract: 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: GrantFiled: April 24, 2014Date of Patent: April 17, 2018Assignee: Air Products and Chemicals, Inc.Inventors: Christopher Michael Ott, Gowri Krishnamurthy, Fei Chen, Yang Liu, Mark Julian Roberts
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Publication number: 20180100694Abstract: 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: ApplicationFiled: October 7, 2016Publication date: April 12, 2018Applicant: Air Products and Chemicals, Inc.Inventors: Gowri Krishnamurthy, Mark Julian Roberts
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Publication number: 20180087832Abstract: 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: ApplicationFiled: September 27, 2016Publication date: March 29, 2018Applicant: Air Products and Chemicals, Inc.Inventors: Mark Julian Roberts, Gowri Krishnamurthy, Adam Adrian Brostow
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Patent number: 9920987Abstract: 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: GrantFiled: May 8, 2015Date of Patent: March 20, 2018Assignee: Air Products and Chemicals, Inc.Inventors: Adam Adrian Brostow, Gowri Krishnamurthy
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Publication number: 20180058752Abstract: 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: ApplicationFiled: August 8, 2017Publication date: March 1, 2018Applicant: AIR PRODUCTS AND CHEMICALS, INC.Inventors: Brian Keith Johnston, Gowri Krishnamurthy, Mark Julian Roberts
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Patent number: 9816754Abstract: 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: GrantFiled: April 24, 2014Date of Patent: November 14, 2017Assignee: Air Products and Chemicals, Inc.Inventors: Fei Chen, Yang Liu, Gowri Krishnamurthy, Christopher Michael Ott, Mark Julian Roberts
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Publication number: 20170284737Abstract: 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: ApplicationFiled: June 19, 2017Publication date: October 5, 2017Applicant: AIR PRODUCTS AND CHEMICALS, INC.Inventors: Fei Chen, Yang Liu, Gowri Krishnamurthy, Christopher Michael Ott, Mark Julian Roberts
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Patent number: 9759480Abstract: 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: GrantFiled: October 10, 2014Date of Patent: September 12, 2017Assignee: Air Products and Chemicals, Inc.Inventors: Brian Keith Johnson, Gowri Krishnamurthy, Mark Julian Roberts
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Patent number: 9631864Abstract: A method and apparatus of removing heavy hydrocarbons from a natural gas feed stream, the method comprising using first and second hydrocarbon removal systems in series such that the first system processes the natural gas feed stream to produce a heavy hydrocarbon depleted natural gas stream and the second system processes at least a portion of the heavy hydrocarbon depleted natural gas stream from the first system to produce a natural gas stream lean in heavy hydrocarbons, wherein one of said systems is a adsorption system that comprises one or more beds of adsorbent for adsorbing and thereby removing heavy hydrocarbons from a heavy hydrocarbon containing natural gas, and the other of said systems is a gas-liquid separation system for separating a heavy hydrocarbon containing natural gas into a heavy hydrocarbon depleted natural gas vapor and a heavy hydrocarbon enriched liquid.Type: GrantFiled: September 12, 2012Date of Patent: April 25, 2017Assignee: Air Products and Chemicals, Inc.Inventors: Fei Chen, Xukun Luo, Christopher Michael Ott, Mark Julian Roberts, Gowri Krishnamurthy
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Publication number: 20170089637Abstract: 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: ApplicationFiled: September 30, 2015Publication date: March 30, 2017Applicant: AIR PRODUCTS AND CHEMICALS, INC.Inventors: Joseph Gerard Wehrman, Gowri Krishnamurthy
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Publication number: 20160327335Abstract: 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: ApplicationFiled: May 8, 2015Publication date: November 10, 2016Applicant: AIR PRODUCTS AND CHEMICALS, INC.Inventors: Adam Adrian Brostow, Gowri Krishnamurthy
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Publication number: 20160216030Abstract: Described herein is a method of and system for fractionating and liquefying a natural gas feed stream. The natural gas is first fractionated in a scrub column. The overhead vapor from the scrub column is cooled, condensed and divided to form a first, a second and at least one further stream of liquefied first overhead. The first stream of liquefied first overhead is returned to the scrub column as a reflux stream. The second stream of liquefied first overhead forms an LNG product. The further stream of liquefied first overhead is used to provide or generate reflux for a de-methanizer column used to fractionate the bottoms liquid from the scrub column.Type: ApplicationFiled: January 23, 2015Publication date: July 28, 2016Applicant: AIR PRODUCTS AND CHEMICALS, INC.Inventors: Timothy Truong, Gowri Krishnamurthy, Mark Julian Roberts