Patents by Inventor Persefoni E. Kechagia

Persefoni E. Kechagia 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).

  • Publication number: 20230352746
    Abstract: A carbon-based additive for negative active materials includes carbon nanostructures free of a fiber substrate, carbon nanostructures fused to a fiber substrate or any combination thereof. In many cases, the carbon-based additive further includes carbon black. The additive is used to prepare electrode compositions for lead acid batteries. Batteries that include such electrode compositions are characterized by improved dynamic charge acceptance and lead utilization, typically at acceptable water loss levels. Some of the batteries described herein exhibit a negligible memory effect.
    Type: Application
    Filed: August 20, 2021
    Publication date: November 2, 2023
    Inventors: Yu-Hua Kao, Agathagelos Kyrlidis, Persefoni E. Kechagia, Paolina Atanassova, Tushar Shah
  • Patent number: 9772139
    Abstract: The invention relates to a process for removing oxygen from liquid argon using a TSA (temperature swing adsorption) cyclical process that includes cooling an adsorbent bed to sustain argon in a liquid phase; supplying the adsorbent bed with a liquid argon feed that is contaminated with oxygen and purifying the liquid argon thereby producing an argon product with less oxygen contaminant than is in the initial liquid argon feed; draining the purified residual liquid argon product and sending purified argon out of the adsorbent bed. Regeneration of specially prepared adsorbent allows the adsorbent bed to warm up to temperatures that preclude the use of requiring either vacuum or evacuation of adsorbent from the bed.
    Type: Grant
    Filed: November 23, 2015
    Date of Patent: September 26, 2017
    Assignee: Praxair Technology, Inc.
    Inventors: Persefoni E. Kechagia, Neil A. Stephenson, Philip A. Barrett, Hai Du, Steven J. Pontonio
  • Patent number: 9759482
    Abstract: A method and apparatus for producing a purified liquid argon product in which liquid argon having oxygen impurities is produced in a cryogenic air separation plant by separating argon from oxygen within an argon column. An impure liquid argon stream, composed of part of the liquid argon, is purified in an adsorbent bed by adsorbing the oxygen impurities in an adsorbent to produce a purified liquid argon stream that constitutes the purified liquid argon product. During adsorption, the adsorbent bed is maintained at a reduced temperature with a coolant to prevent vaporization of the liquid argon. The bed is then regenerated by draining residual liquid argon from the adsorbent bed, introducing the residual liquid argon back into the air separation plant and then desorbing the oxygen impurities with a regeneration gas. After regeneration, the adsorbent bed is refilled with purified liquid argon prior to being brought back on-line.
    Type: Grant
    Filed: March 24, 2017
    Date of Patent: September 12, 2017
    Assignee: PRAXAIR TECHNOLOGY, INC.
    Inventors: Henry E. Howard, Persefoni E. Kechagia, Philip A. Barrett, James R. Handley
  • Publication number: 20170198968
    Abstract: A method and apparatus for producing a purified liquid argon product in which liquid argon having oxygen impurities is produced in a cryogenic air separation plant by separating argon from oxygen within an argon column. An impure liquid argon stream, composed of part of the liquid argon, is purified in an adsorbent bed by adsorbing the oxygen impurities in an adsorbent to produce a purified liquid argon stream that constitutes the purified liquid argon product. During adsorption, the adsorbent bed is maintained at a reduced temperature with a coolant to prevent vaporization of the liquid argon. The bed is then regenerated by draining residual liquid argon from the adsorbent bed, introducing the residual liquid argon back into the air separation plant and then desorbing the oxygen impurities with a regeneration gas. After regeneration, the adsorbent bed is refilled with purified liquid argon prior to being brought back on-line.
    Type: Application
    Filed: March 24, 2017
    Publication date: July 13, 2017
    Inventors: Henry E. Howard, Persefoni E. Kechagia, Philip A. Barrett, James R. Handley
  • Patent number: 9644890
    Abstract: A method and apparatus for producing a purified liquid argon product in which liquid argon having oxygen impurities is produced in a cryogenic air separation plant by separating argon from oxygen within an argon column. An impure liquid argon stream, composed of part of the liquid argon, is purified in an adsorbent bed by adsorbing the oxygen impurities in an adsorbent to produce a purified liquid argon stream that constitutes the purified liquid argon product. During adsorption, the adsorbent bed is maintained at a reduced temperature with a coolant to prevent vaporization of the liquid argon. The bed is then regenerated by draining residual liquid argon from the adsorbent bed, introducing the residual liquid argon back into the air separation plant and then desorbing the oxygen impurities with a regeneration gas. After regeneration, the adsorbent bed is refilled with purified liquid argon prior to being brought back on-line.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: May 9, 2017
    Assignee: PRAXAIR TECHNOLOGY, INC.
    Inventors: Henry E. Howard, Persefoni E. Kechagia, Philip A. Barrett, James R. Handley
  • Patent number: 9457337
    Abstract: An optimal material composition that allows for the purification of at least one feed component from a fluid feed stream such that the adsorbent has an oxygen capacity of at least 10 weight percent is described. More specifically, the material is an adsorbent for purification of a fluid feed stream having an oxygen to argon selectivity greater than or equal to a ratio of 3:1 and an oxygen capacity of greater than or equal to 10 weight percent, wherein the oxygen capacity is measured at a pressure in the range of about 9-10 Torr and a temperature of 77 degrees Kelvin after 4 hours of equilibration time and wherein the oxygen to argon selectivity is obtained by dividing the oxygen capacity by the argon capacity of the adsorbent measured at a pressure in the range of about 697-700 Torr and a temperature of 87 degrees Kelvin after 8 hours of equilibration time. The adsorption capacities are measured on a pure component basis.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: October 4, 2016
    Assignee: PRAXAIR TECHNOLOGY, INC.
    Inventors: Philip A. Barrett, Steven J. Pontonio, Neil A. Stephenson, Persefoni E. Kechagia
  • Publication number: 20160084571
    Abstract: The invention relates to a process for removing oxygen from liquid argon using a TSA (temperature swing adsorption) cyclical process that includes cooling an adsorbent bed to sustain argon in a liquid phase; supplying the adsorbent bed with a liquid argon feed that is contaminated with oxygen and purifying the liquid argon thereby producing an argon product with less oxygen contaminant than is in the initial liquid argon feed; draining the purified residual liquid argon product and sending purified argon out of the adsorbent bed. Regeneration of specially prepared adsorbent allows the adsorbent bed to warm up to temperatures that preclude the use of requiring either vacuum or evacuation of adsorbent from the bed.
    Type: Application
    Filed: November 23, 2015
    Publication date: March 24, 2016
    Inventors: PERSEFONI E. KECHAGIA, Neil A. Stephenson, Philip A. Barrett, Hai Du, Steven J. Pontonio
  • Patent number: 9222727
    Abstract: The invention relates to a process for removing oxygen from liquid argon using a TSA (temperature swing adsorption) cyclical process that includes cooling an adsorbent bed to sustain argon in a liquid phase; supplying the adsorbent bed with a liquid argon feed that is contaminated with oxygen and purifying the liquid argon thereby producing an argon product with less oxygen contaminant than is in the initial liquid argon feed; draining the purified residual liquid argon product and sending purified argon out of the adsorbent bed. Regeneration of specially prepared adsorbent allows the adsorbent bed to warm up to temperatures that preclude the use of requiring either vacuum or evacuation of adsorbent from the bed.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: December 29, 2015
    Assignee: Praxair Technology, Inc.
    Inventors: Persefoni E. Kechagia, Neil A. Stephenson, Philip A. Barrett, Hai Du, Steven J. Pontonio
  • Publication number: 20140245781
    Abstract: The invention relates to a process for removing oxygen from liquid argon using a TSA (temperature swing adsorption) cyclical process that includes cooling an adsorbent bed to sustain argon in a liquid phase; supplying the adsorbent bed with a liquid argon feed that is contaminated with oxygen and purifying the liquid argon thereby producing an argon product with less oxygen contaminant than is in the initial liquid argon feed; draining the purified residual liquid argon product and sending purified argon out of the adsorbent bed. Regeneration of specially prepared adsorbent allows the adsorbent bed to warm up to temperatures that preclude the use of requiring either vacuum or evacuation of adsorbent from the bed.
    Type: Application
    Filed: March 1, 2013
    Publication date: September 4, 2014
    Inventors: Persefoni E. Kechagia, Neil A. Stephenson, Philip A. Barrett, Hai Du, Steven J. Pontonio
  • Publication number: 20140249023
    Abstract: An optimal material composition that allows for the purification of at least one feed component from a fluid feed stream such that the adsorbent has an oxygen capacity of at least 10 weight percent is described. More specifically, the material is an adsorbent for purification of a fluid feed stream having an oxygen to argon selectivity greater than or equal to a ratio of 3:1 and an oxygen capacity of greater than or equal to 10 weight percent, wherein the oxygen capacity is measured at a pressure in the range of about 9-10 Torr and a temperature of 77 degrees Kelvin after 4 hours of equilibration time and wherein the oxygen to argon selectivity is obtained by dividing the oxygen capacity by the argon capacity of the adsorbent measured at a pressure in the range of about 697-700 Torr and a temperature of 87 degrees Kelvin after 8 hours of equilibration time. The adsorption capacities are measured on a pure component basis.
    Type: Application
    Filed: March 1, 2013
    Publication date: September 4, 2014
    Inventors: Philip A. Barrett, Steven J. Pontonio, Neil A. Stephenson, Persefoni E. Kechagia
  • Publication number: 20140245782
    Abstract: A method and apparatus for producing a purified liquid argon product in which liquid argon having oxygen impurities is produced in a cryogenic air separation plant by separating argon from oxygen within an argon column. An impure liquid argon stream, composed of part of the liquid argon, is purified in an adsorbent bed by adsorbing the oxygen impurities in an adsorbent to produce a purified liquid argon stream that constitutes the purified liquid argon product. During adsorption, the adsorbent bed is maintained at a reduced temperature with a coolant to prevent vaporization of the liquid argon. The bed is then regenerated by draining residual liquid argon from the adsorbent bed, introducing the residual liquid argon back into the air separation plant and then desorbing the oxygen impurities with a regeneration gas. After regeneration, the adsorbent bed is refilled with purified liquid argon prior to being brought back on-line.
    Type: Application
    Filed: February 27, 2014
    Publication date: September 4, 2014
    Inventors: Henry E. Howard, Persefoni E. Kechagia, Philip A. Barrett, James R. Handley