Patents by Inventor Ravi Prasad

Ravi Prasad 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: 20020127177
    Abstract: Methane is formed into synthesis gas through a combination of a partial oxidation reaction and a steam reforming reaction. Oxygen for the partial oxidation reaction is obtained by contacting air with an oxygen transport membrane and recovering the oxygen transported through the membrane. To increase the oxygen flux through the membrane, steam is utilized as a sweep gas on the anode side of the membrane. The steam reduces the oxygen partial pressure on the anode side increasing the flux. The efficiency and cost benefit of the process is enhanced by utilizing in-line combustors to heat gases being delivered to the oxygen transport membrane. Membrane integrity is enhanced by conducting the reactions in a reactor that is remote from the oxygen transport membrane.
    Type: Application
    Filed: December 29, 2000
    Publication date: September 12, 2002
    Inventors: Christian Friedrich Gottzmann, Ravi Prasad, Joseph Michael Schwartz
  • Publication number: 20020078906
    Abstract: An oxygen selective ion transport membrane is integrated with a boiler furnace to generate steam and, optionally, high purity oxygen and nitrogen. The heat required to drive the system is obtained by the combustion of an oxygen transported through the oxygen selective ion transport membrane with a high BTU fuel such as methane or natural gas. NOx compound formation is minimized either by utilizing a combustion products diluted air/fuel mixture for combustion in the boiler furnace or by limiting combustion to a mixture of oxygen and a fuel.
    Type: Application
    Filed: October 26, 2001
    Publication date: June 27, 2002
    Inventors: Ravi Prasad, Hisashi Kobayashi, Pauline Jane Cook
  • Patent number: 6406518
    Abstract: A process (and corresponding system) for separating a high purity gas (e.g. oxygen) from a feed gas stream (e.g. air) that includes heating the feed gas stream before passing the heated feed gas stream through a ceramic membrane to separate a gas component from the other components of the gas stream.
    Type: Grant
    Filed: August 21, 2000
    Date of Patent: June 18, 2002
    Assignee: Praxair Technology, Inc.
    Inventors: Dante Patrick Bonaquist, John Fredric Billingham, Joseph Michael Schwartz, Ravi Prasad
  • Patent number: 6402988
    Abstract: An exothermic reaction and an endothermic reaction are thermally combined in a reactor having at least one oxygen selective ion transport membrane that provides the exothermic reaction with oxygen from an oxygen-containing gas such as air. The thermal requirements of the endothermic reaction are satisfied by the exothermic reaction. Dependent on the reactor design employed, the exothermic and endothermic reactions may be gaseously combined.
    Type: Grant
    Filed: July 17, 2000
    Date of Patent: June 11, 2002
    Assignees: Praxair Technology, Inc., The Standard Oil Company
    Inventors: Christian Friedrich Gottzmann, Ravi Prasad, Joseph Michael Schwartz, Victor Emmanuel Bergsten, James Eric White, Terry J. Mazanec, Thomas L. Cable, John C. Fagley
  • Patent number: 6395206
    Abstract: A method of removing an organic binder from a green ceramic form in which a green ceramic form is subjected to a flowing carbon dioxide containing atmosphere having a sufficiently low oxygen content to allow about 60% or more of the organic binder to be oxidized by carbon dioxide. The green ceramic form is heated to the oxidation temperature at a rate greater than about 0.1° C. and is maintained under oxidizing temperature conditions until at least about 90% of the organic binder oxidizes.
    Type: Grant
    Filed: June 5, 2000
    Date of Patent: May 28, 2002
    Assignee: Praxair Technology, Inc.
    Inventors: Prasad Apte, Ravi Prasad
  • Patent number: 6368383
    Abstract: A method of separating oxygen from an oxygen containing gas with a composite membrane capable of conducting oxygen ions and electrons. In accordance with the method, the composite membrane is subjected to an operational temperature and the oxygen containing gas at a cathode side thereof. The composite membrane has a dense layer, at least one active porous layer contiguous to the dense layer, and at least one porous support layer. The active porous layer has a thickness and a distribution of pore radii. The distribution of pore radii has a standard deviation from a theoretical radius that would produce a maximum operation flux through the thickness when the thickness is about equal to a product of a constant and the square root of the theoretical radius. The constant is a function of a material used to fabricate the active porous layer, the operational temperature and an oxygen partial pressure within the active porous layer, and a porosity and a tortuosity produced by the pore radii.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: April 9, 2002
    Assignee: Praxair Technology, Inc.
    Inventors: Anil V. Virkar, Christian Friedrich Gottzmann, Ravi Prasad, Bart Antonie Van Hassel
  • Patent number: 6332964
    Abstract: A multi-phase solid electrolyte ion transport membrane comprising at least two phases wherein one of the phases comprises an oxygen ion single conductive material. The other phase comprises an electronically-conductive metal or metal oxide conducting phase is present in a low volume percentage. One method for achieving this result incorporates the minority phase into the powder from which the membrane is made by deposition of the metal or metal oxide from a polymer made by polymerizing a chelated metal dispersion in a polymerizable organic monomer or prepolymer. The multi-phase composition advantageously comprises a first phase of a ceramic material and a second phase of a metal or metal oxide bound to a surface of the ceramic material. A second method fabricates the membrane from a mixture of two powders one of which contains a mixture of the two phases.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: December 25, 2001
    Assignees: Praxair Technology, Inc., BP Amoco Corporation
    Inventors: Chieh Cheng Chen, Ravi Prasad, Terry J. Mazanec, Charles J. Besecker
  • Patent number: 6296686
    Abstract: Syngas, a mixture of hydrogen and carbon monoxide, is an intermediate in the conversion of methane to liquid fuels. For certain applications, it is desirable to maintain an H2/CO molar ratio of about 3. This molar ratio is achieved by steam reforming of methane in accordance with: CH4+H2O→3H2+CO. To provide the heat required to drive the endothermic steam reforming reaction, a low grade fuel is combusted in a reactor and the heat of combustion conducted to the endothermic reaction. By using an oxygen selective ion transport membrane element to transport the oxygen required for combustion, the formation of undesirable NOx compounds is minimized.
    Type: Grant
    Filed: August 31, 1998
    Date of Patent: October 2, 2001
    Assignee: Praxair Technology, Inc.
    Inventors: Ravi Prasad, Christian Friedrich Gottzmann
  • Patent number: 6187157
    Abstract: A multi-phase solid electrolyte ion transport membrane comprising at least two phases wherein one of the phases comprises an oxygen ion single conductive material, or a mixed conductor. The other phase comprises an electronically-conductive metal or metal oxide that is incorporated into the membrane by deposition of the metal or metal oxide from a polymer made by polymerizing a chelated metal dispersion in a polymerizable organic monomer or prepolymer. The multi-phase composition advantageously comprises a first phase of a ceramic material and a second phase of a metal or metal oxide bound to a surface of the ceramic material. The multi-phase composition is advantageously prepared in an in-situ fashion before fabricating the membrane matrix. As another alternative, a preformed ceramic matrix is surface-coated with a metal or metal oxide.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: February 13, 2001
    Assignee: Praxair Technology, Inc.
    Inventors: Chieh-Cheng Chen, Ravi Prasad
  • Patent number: 6165553
    Abstract: A method of fabricating a dense membrane by providing a colloidal suspension of a ceramic powder, and providing a polymeric precursor. The precursor is mixed together with the colloidal suspension, and the mixture is applied to a membrane support to form a composite structure. The composite structure is heated to form a dense membrane on the support.
    Type: Grant
    Filed: August 26, 1998
    Date of Patent: December 26, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Chieh-Cheng Chen, Ravi Prasad
  • Patent number: 6153163
    Abstract: A process to generate an enhanced output of a desired product from an ion transport reactor utilizes the reaction products from both the cathode side and the anode side of an oxygen selective ion transport ceramic membrane. An oxygen donating first feed stream containing the desired product in a chemically bound state is delivered to the cathode side while an oxygen accepting second feed stream is delivered to the anode side. Following chemical reactions on both the cathode side and the anode side, a desired product is recovered from a first product stream exiting from the cathode side and from a second product stream exiting from the anode side such that the sum of the desired product contained within the two product streams exceeds that attainable from either product stream alone.
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: November 28, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Ravi Prasad, Christian Friedrich Gottzmann, Joseph Michael Schwartz
  • Patent number: 6146445
    Abstract: A stable substantially cubic perovskite crystalline structure of at least one strontium-doped lanthanum cobalt oxide (LSC) having a stabilizing amount of at least one cerium gadolinium oxide (CGO) therein.
    Type: Grant
    Filed: June 1, 1999
    Date of Patent: November 14, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Chieh-Cheng Chen, Ravi Prasad
  • Patent number: 6139810
    Abstract: A reactor comprising: a hollow shell defining a hermetic enclosure; a plurality of tube sheets disposed within said hermetic enclosure, a first one of said plurality of tube sheets defining a first chamber; at least one reaction tube each having a first end and an opposing second end, said first end being fixedly attached and substantially hermetically sealed to one end of said plurality of tube sheets and opening into said first chamber, the second end being axially unrestrained; each of said reaction tubes is comprised of an oxygen selective ion transport membrane with an anode side wherein said oxygen selective ion transport membrane is formed from a mixed conductor metal oxide that is effective for the transport of elemental oxygen at elevated temperatures and at least a portion of said first and second heat transfer sections are formed of metal; each of said reaction tubes includes first and second heat transfer sections and a reaction section, said reaction section disposed between said first and second
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: October 31, 2000
    Assignees: Praxair Technology, Inc., The Standard Oil Company
    Inventors: Christian Friedrich Gottzmann, Ravi Prasad, Joseph Michael Schwartz, Victor Emmanuel Bergsten, James Eric White, Terry J. Mazanec, Thomas L. Cable, John C. Fagley
  • Patent number: 6139604
    Abstract: A low energy cost process for the co-production of oxygen and nitrogen employing a fuel tube extending into the first oxygen selective ion transport membrane whereby fuel is introduced adjacent to the closed end and flows cocurrently with oxygen containing gas in the annulus and an oxygen selective ion transport membrane having a separator section and a reactor section. An oxygen-containing feedstock, typically air, is compressed and then contacts the cathode side of the separator section where a portion of the oxygen contained within the feedstock is transported to the anode side of the separator section and recovered as an oxygen product gas. Substantially the remainder of the oxygen contained within the feedstock is transported from the cathode side of the reactor section to the anode side and exothermically reacted with a fuel. Following the exothermic reaction, hot nitrogen rich product gas is expanded in a turbine to generate the power necessary to compress the feedstock.
    Type: Grant
    Filed: November 4, 1998
    Date of Patent: October 31, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Christian Friedrich Gottzmann, Ravi Prasad, Nitin Ramesh Keskar, James Bragdon Wulf
  • Patent number: 6117210
    Abstract: A process for separating a feed gas stream containing elemental oxygen and at least one other gas into an oxygen product gas stream having a selected concentration of oxygen, by removing the oxygen from a feed gas stream using an ion transport module containing an ion transport membrane having a retentate side and a permeate side to produce both an ultrapure oxygen gas stream emerging from the membrane into the permeate side and a retentate gas stream. The ultrapure oxygen gas stream is blended with an additive gas stream to produce an oxygen product gas stream having a selected concentration of oxygen.
    Type: Grant
    Filed: April 29, 1997
    Date of Patent: September 12, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Ravi Prasad, Christian Friedrich Gottzmann
  • Patent number: 6106591
    Abstract: A process for inhibiting the formation of carbon and/or coke from a carbon-containing reactive gas stream on the permeate side of an oxygen ion transport membrane, or for increasing the oxygen partial pressure thereon, by separating a feed gas stream to form an oxygen-depleted gas stream on the retentate side and a gas stream containing oxygen reaction products on the permeate side. The permeate side is purged with the carbon-containing reactive gas stream, and at least a portion of the exhaust gas stream formed from the reaction of the reactive gas stream with the separated oxygen is recirculated to purge the permeate side.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: August 22, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Nitin Ramesh Keskar, Ravi Prasad, Christian Friedrich Gottzmann
  • Patent number: 6066307
    Abstract: A process for producing synthesis gas and hydrogen by passing a compressed and heated oxygen-containing gas mixture into a reactor having at least one solid electrolyte oxygen ion transport membrane to separate transported oxygen Organic fuel reacts with the oxygen to form synthesis gas. The resulting synthesis gas is separated into hydrogen gas through at least one solid electrolyte hydrogen transport membrane to separate the transported hydrogen in the same or different separator.
    Type: Grant
    Filed: September 15, 1999
    Date of Patent: May 23, 2000
    Inventors: Nitin Ramesh Keskar, Ravi Prasad, Christian Friedrich Gottzmann
  • Patent number: 6017646
    Abstract: An integrated system utilizing a solid oxide fuel cell and at least one ion transport reactor to generate electric power and a product gas by delivering an oxygen-containing gas, typically air, to a first cathode side of the solid oxide fuel cell and delivering a gaseous fuel to a first anode side. Oxygen ions are transported through a membrane in the fuel cell to the first anode side and exothermally react with the gaseous fuel to generate electric power and heat. The heat and oxygen transport produces a higher-temperature, reduced-oxygen-content gaseous retentate stream exiting the cathode side of the solid oxide fuel cell which is delivered to a first ion transport reactor where a substantial portion of the residual oxygen is transported through an oxygen selective ion transport membrane. A product gas stream is then recovered.
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: January 25, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Ravi Prasad, Christian Friedrich Gottzmann, Nitin Ramesh Keskar
  • Patent number: 6010614
    Abstract: A method for maintaining the temperature of an oxygen-selective ion transport membrane within a desired temperature range includes providing an ion transport reactor with the oxygen-selective ion transport membrane. An oxygen-donating feed gas is delivered to a cathode side at a first temperature, at a first rate, and at a first oxygen partial pressure and a reactant gas is supplied to an anode side at a second temperature and a second rate. A physical condition is then established within the ion transport reactor that favors the transport of elemental oxygen through the oxygen selective ion transport membrane as oxygen ions. One or more process variables are then regulated to maintain the temperature of the oxygen selective ion transport membrane within the desired range.
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: January 4, 2000
    Assignee: Praxair Technology, Inc.
    Inventors: Nitin Ramesh Keskar, Ravi Prasad, Christian Friedrich Gottzmann
  • Patent number: 5976223
    Abstract: A process for producing at least an oxygen product gas stream, and power from a gas turbine, by compressing a feed gas stream containing elemental oxygen and heating the feed gas stream on the retentate side of an ion transport reactor membrane section to produce a heated feed gas stream. Oxygen permeating the ion transport reactor membrane section is reacted with a first fuel gas stream to produce a first combustion products gas stream. The heated feed gas stream is separated using an ion transport separator membrane section having a retentate side and a permeate side into an oxygen-depleted gas stream on the retentate side and an oxygen-containing gas stream on the permeate side. At least a portion of the first combustion products gas stream can be recovered, and energy is extracted from at least one gas stream to be expanded in a gas turbine to produce energy.
    Type: Grant
    Filed: November 18, 1997
    Date of Patent: November 2, 1999
    Assignee: Praxair Technology, Inc.
    Inventors: Ravi Prasad, Christian Friedrich Gottzmann