Patents by Inventor Vasilis Papavassiliou
Vasilis Papavassiliou 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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Patent number: 8007761Abstract: Carbon dioxide emissions within a refinery are reduced by reforming a hydrocarbon containing feed at low pressure to enhance the conversion of methane to hydrogen and carbon monoxide and thereby reduce methane slip. The hydrocarbon containing feed is composed entirely or at least in part of a refinery off gas. The resulting reformed stream is then subjected to water-gas shift conversion to form a shifted stream from which carbon dioxide is separated. As a result of the separation and the low pressure reforming, hydrogen containing fuel gas streams, that are thereby necessary lean in carbon dioxide and methane, are used in firing the steam methane reformer and other fuel uses within the refinery to reduce carbon dioxide emissions. The carbon dioxide that is separated can be sequestered or used in other processes such as enhanced oil recovery.Type: GrantFiled: December 24, 2008Date of Patent: August 30, 2011Assignee: Praxair Technology, Inc.Inventors: Raymond Francis Drnevich, Minish Mahendra Shah, Vasilis Papavassiliou
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Publication number: 20110085967Abstract: A method and apparatus for producing a hydrogen containing product in which hydrocarbon containing feed gas streams are reacted in a steam methane reformer of an existing hydrogen plant and a catalytic reactor that reacts hydrocarbons, oxygen and steam. The catalytic reactor is a retrofit to the existing hydrogen plant to increase hydrogen production. The resulting synthesis gas streams are combined, cooled, subjected to water-gas shift and then introduced into a production apparatus that can be a pressure swing adsorption unit. The amount of synthesis gas contained in a shifted stream made available to the production apparatus is increased by virtue of the combination of the synthesis gas streams to increase production of the hydrogen containing product. The catalytic reactor is operated such that the synthesis gas stream produced by such reactor is similar to that produced by the steam methane reformer and at a temperature that will reduce oxygen consumption within the catalytic reactor.Type: ApplicationFiled: October 14, 2009Publication date: April 14, 2011Inventors: Troy Michael Raybold, Gregory Joseph Panuccio, Jerome Thomas Jankowiak, Vasilis Papavassiliou, Raymond Francis Drnevich
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Publication number: 20110077437Abstract: Organic sulfur compounds contained in refinery off gas streams having either high ort low concentrations of olefins are converted to hydrogen sulfides which can be then be removed using conventional amine treating systems. The process uses a catalytic reactor with or without a hydrotreater depending on the olefin concentration of the off gas stream. The catalytic reactor operates in a hydrogenation mode or an oxidation mode to convert a majority of organic sulfur compounds into hydrogen sulfides.Type: ApplicationFiled: August 16, 2010Publication date: March 31, 2011Inventors: Minish Mahendra Shah, Raymond Francis Drnevich, Vasilis Papavassiliou
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Publication number: 20110034745Abstract: The present invention provides a method and apparatus for producing a treated hydrocarbon containing stream for use as a feed to a steam methane reformer of a hydrogen plant. In accordance with such method, amounts of olefins and organic sulfur species within an untreated feed are decreased in a reactor that is operated in either a hydrogenation mode to hydrogenate the olefins into saturated hydrocarbons or a pre-reforming mode in which hydrocarbon containing two or more carbon atoms including the olefins are reacted with oxygen and steam to form saturated hydrocarbons, methane, additional hydrogen and carbon monoxide. The reactor is configured and operates at a sufficiently high space velocity that olefin and organic species slip occurs that is further treated in a hydrotreater. The reactor contains a catalyst capable of promoting both hydrogenation and oxidation reactions and the hydrotreater contains a catalyst that is capable of only promoting hydrogenation reactions.Type: ApplicationFiled: August 4, 2009Publication date: February 10, 2011Inventors: Troy M. Raybold, Raymond Francis Drnevich, Vasilis Papavassiliou
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Publication number: 20110031162Abstract: A method and apparatus for producing a treated hydrocarbon containing stream for use as a feed to a hydrogen plant having a steam methane reformer in which an untreated hydrocarbon containing stream is introduced into two reaction stages connected in series to hydrogenate olefins and to convert organic sulfur species to hydrogen sulfide. The second of the two stages can also be operated in a pre-reforming mode to generate additional hydrogen through introduction of the oxygen and steam into such stage. A sulfur tolerant catalyst is used in both stages to promote hydrogenation and oxidation reactions. Sulfur is removed between stages by adsorption of the hydrogen sulfide to prevent deactivation of the catalyst in the second of the stages that would otherwise occur during operation of the second reaction stage in a pre-reforming mode of operation.Type: ApplicationFiled: August 4, 2009Publication date: February 10, 2011Inventors: Raymond Francis Drnevich, Vasilis Papavassiliou, Troy M. Raybold, Perry Raymond Pacouloute
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Publication number: 20100158776Abstract: Carbon dioxide emissions within a refinery are reduced by reforming a hydrocarbon containing feed at low pressure to enhance the conversion of methane to hydrogen and carbon monoxide and thereby reduce methane slip. The hydrocarbon containing feed is composed entirely or at least in part of a refinery off gas. The resulting reformed stream is then subjected to water-gas shift conversion to form a shifted stream from which carbon dioxide is separated. As a result of the separation and the low pressure reforming, hydrogen containing fuel gas streams, that are thereby necessary lean in carbon dioxide and methane, are used in firing the steam methane reformer and other fuel uses within the refinery to reduce carbon dioxide emissions. The carbon dioxide that is separated can be sequestered or used in other processes such as enhanced oil recovery.Type: ApplicationFiled: December 24, 2008Publication date: June 24, 2010Inventors: Raymond Francis Drnevich, Minish Mahendra Shah, Vasilis Papavassiliou
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Patent number: 7547422Abstract: A catalytic reactor having a mixing section connected to a downstream reaction section containing a catalyst to promote a reaction of oxygen and a hydrocarbon fed to the catalytic reactor. The mixing section is provided with a flame arrestor to prevent a stable flame from propagating should any reaction of oxygen and hydrocarbons occur during mixing. The flame arrestor permits flow in both axial and radial directions to promote mixing. Baffle elements and a downstream static mixer can also be used. The catalyst is preferably in the form of monolithic blocks enclosed by a ceramic tube that is maintained as a unitary catalyst assembly that can be removed for replacement and installation of the catalyst as a single unit.Type: GrantFiled: March 13, 2006Date of Patent: June 16, 2009Assignee: Praxair Technology, Inc.Inventors: Vasilis Papavassiliou, Shawn Michael Cecula, Perry Pacouloute, Thomas Edward Gajewski
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Publication number: 20090013600Abstract: The present invention relates to systems and processes for producing syngas in steam methane reformer (SMR)-based plants, particularly to the use of a high space velocity, dual mode catalytic reactor to pre-reform plant feedstock. The dual mode reactor has the capability to operate in two modes: either without oxygen addition in a reforming mode or with oxygen addition in a partial oxidation-reforming mode. The dual mode reactor allows the syngas production rate of the plant to be manipulated without the added capital expense of a reheat coil and with reduced impact on export steam production.Type: ApplicationFiled: May 22, 2008Publication date: January 15, 2009Applicant: Praxair Technology, Inc.Inventors: Raymond Francis Drnevich, Vasilis Papavassiliou, Troy Michael Raybold, Ramchandra Mukund Watwe
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Publication number: 20080168774Abstract: Method of preparing and introducing fuel into the combustors of a gas turbine in which a hydrocarbon containing feed, oxygen and steam are introduced into a catalytic partial oxidation reactor to produce a product stream. The hydrocarbon containing feed contains no less than about 15 percent by volume on a dry basis of hydrocarbons with at least two carbon atoms and/or at least about 3 percent by volume of olefins. The reactant mixture formed of the hydrocarbon containing feed, oxygen and steam has an oxygen to carbon ratio of between about 0.08 and about 0.25 and a water to carbon ratio of between about 0.05 to about 0.5. The hydrocarbon containing feed is introduced into the reactor alone or with a steam at a temperature no greater than 600° C. and the product stream is produced at a temperature of between about 600° C. and 860° C. and contains less than about 0.5 percent of olefins and less than 10 percent of hydrocarbons with two or more carbon atoms on a dry basis.Type: ApplicationFiled: February 18, 2005Publication date: July 17, 2008Inventors: Raymond Francis Drnevich, Vasilis Papavassiliou
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Patent number: 7395670Abstract: Method of preparing and introducing fuel into the combustors of a gas turbine in which a hydrocarbon containing feed, oxygen and steam are introduced into a catalytic partial oxidation reactor to produce a product stream. The hydrocarbon containing feed contains no less than about 15 percent by volume on a dry basis of hydrocarbons with at least two carbon atoms and/or at least about 3 percent by volume of olefins. The reactant mixture formed of the hydrocarbon containing feed, oxygen and steam has an oxygen to carbon ratio of between about 0.08 and about 0.25 and a water to carbon ratio of between about 0.05 to about 0.5. The hydrocarbon containing feed is introduced into the reactor alone or with a steam at a temperature no greater than 600° C. and the product stream is produced at a temperature of between about 600° C. and 860° C. and contains less than about 0.5 percent of olefins and less than 10 percent of hydrocarbons with two or more carbon atoms on a dry basis.Type: GrantFiled: February 18, 2005Date of Patent: July 8, 2008Assignee: Praxair Technology, Inc.Inventors: Raymond Francis Drnevich, Vasilis Papavassiliou
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Publication number: 20070212276Abstract: A catalytic reactor having a mixing section connected to a downstream reaction section containing a catalyst to promote a reaction of oxygen and a hydrocarbon fed to the catalytic reactor. The mixing section is provided with a flame arrestor to prevent a stable flame from propagating should any reaction of oxygen and hydrocarbons occur during mixing. The flame arrestor permits flow in both axial and radial directions to promote mixing. Baffle elements and a downstream static mixer can also be used. The catalyst is preferably in the form of monolithic blocks enclosed by a ceramic tube that is maintained as a unitary catalyst assembly that can be removed for replacement and installation of the catalyst as a single unit.Type: ApplicationFiled: March 13, 2006Publication date: September 13, 2007Inventors: Vasilis Papavassiliou, Shawn Cecula, Perry Pacouloute, Thomas Gajewski
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Patent number: 7255840Abstract: An autothermal reactor and method for producing synthesis gas in which a heated oxygen containing stream is expanded into a mixing chamber to entrain a hydrocarbon containing stream to form a reactant stream without reaction of the oxygen and hydrocarbon contents of the streams. The reactant stream is reacted in a series of sequential catalytic reaction zones to react the hydrocarbon and oxygen contained in the reactant stream to form the synthesis gas. The sequential catalytic reaction zones are configured such that an initial partial oxidation reaction occurs that is followed by endothermic reforming reactions having ever decreasing temperatures. The sequential catalytic reaction zones in which the endothermic reforming reactions occur contain a precious metal catalyst supported on ceramic supports that have successively greater surface areas to compensate for the temperature decrease while remaining stable and without a transform in state.Type: GrantFiled: June 26, 2003Date of Patent: August 14, 2007Assignee: Praxair Technology, Inc.Inventors: Vasilis Papavassiliou, Minish Mahendra Shah, Thomas John Bergman, Jr.
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Publication number: 20060104896Abstract: A steam methane reforming method in which a feed stream is treated in a reactor containing a catalyst that is capable of promoting both hydrogenation and partial oxidation reactions. The reactor is either operated in a catalytic hydrogenation mode to convert olefins into saturated hydrocarbons and/or to chemically reduce sulfur species to hydrogen sulfide or a catalytic oxidative mode utilizing oxygen and steam to prereform the feed and thus, increase the hydrogen content of a synthesis gas produced by a steam methane reformer. The method is applicable to the treatment of feed streams containing at least 15% by volume of hydrocarbons with two or more carbon atoms and/or 3% by volume of olefins, such as a refinery off-gas. In such case, the catalytic oxidative mode is conducted with a steam to carbon ratio of less than 0.5, an oxygen to carbon ratio of less than 0.25 and a reaction temperature of between about 500° C. and about 860° C.Type: ApplicationFiled: June 14, 2005Publication date: May 18, 2006Inventors: Raymond Drnevich, Vasilis Papavassiliou
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Patent number: 7037485Abstract: A steam methane reforming method in which a feed stream is treated in a reactor containing a catalyst that is capable of promoting both hydrogenation and partial oxidation reactions. The reactor is either operated in a catalytic hydrogenation mode to convert olefins into saturated hydrocarbons and/or to chemically reduce sulfur species to hydrogen sulfide or a catalytic oxidative mode utilizing oxygen and steam to prereform the feed and thus, increase the hydrogen content of a synthesis gas produced by a steam methane reformer. The method is applicable to the treatment of feed streams containing at least 15% by volume of hydrocarbons with two or more carbon atoms and/or 3% by volume of olefins, such as a refinery off-gas. In such case, the catalytic oxidative mode is conducted with a steam to carbon ratio of less than 0.5, an oxygen to carbon ratio of less than 0.25 and a reaction temperature of between about 500° C. and about 860° C.Type: GrantFiled: June 14, 2005Date of Patent: May 2, 2006Assignee: Praxair Technology, Inc.Inventors: Raymond Francis Drnevich, Vasilis Papavassiliou
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Publication number: 20040265224Abstract: An autothermal reactor and method for producing synthesis gas in which a heated oxygen containing stream is expanded into a mixing chamber to entrain a hydrocarbon containing stream to form a reactant stream without reaction of the oxygen and hydrocarbon contents of the streams. The reactant stream is reacted in a series of sequential catalytic reaction zones to react the hydrocarbon and oxygen contained in the reactant stream to form the synthesis gas. The sequential catalytic reaction zones are configured such that an initial partial oxidation reaction occurs that is followed by endothermic reforming reactions having ever decreasing temperatures. The sequential catalytic reaction zones in which the endothermic reforming reactions occur contain a precious metal catalyst supported on ceramic supports that have successively greater surface areas to compensate for the temperature decrease while remaining stable and without a transform in state.Type: ApplicationFiled: June 26, 2003Publication date: December 30, 2004Inventors: Vasilis Papavassiliou, Minish Mahendra Shah, Thomas John Bergman
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Patent number: 6215027Abstract: The amount of a ballast gas needed, to prevent combustion, deflagration, and/or detonations during a liquid phase reaction of molecular oxygen and a flammable process liquid, is reduced by using a ballast gas other than nitrogen. The ballast gas is selected to have a boiling point lower than the boiling point of the flammable process liquid and selected to produce a higher limiting oxygen value (LOV) in a mixture with the flammable process liquid vapor and molecular oxygen than the LOV for the corresponding mixture substituting just nitrogen for the inerting gas.Type: GrantFiled: October 20, 1998Date of Patent: April 10, 2001Assignee: Praxair Technology, Inc.Inventors: Vasilis Papavassiliou, William Robert Williams, Matthew Lincoln Wagner
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Patent number: 6040467Abstract: This invention is directed to a method for producing ethylene oxide comprising feeding ethylene, high purity oxygen and a ballast gas with a recycle gas in a catalyst filled reactor to form a gaseous mixture; passing the gaseous mixture from the reactor to a recovery unit to selectively separate ethylene oxide and carbon dioxide containing gas; passing at least a portion of the carbon dioxide containing gas to a stripping unit to selectively separate carbon dioxide and a waste gas; passing at least a portion of the waste gas to purge and another portion for recycling as the recycle gas; and recovering ethylene oxide from the recovery unit.Type: GrantFiled: July 24, 1997Date of Patent: March 21, 2000Assignee: Praxair Technology, Inc.Inventors: Vasilis Papavassiliou, Matthew Lincoln Wagner, Roger William Day
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Patent number: 5952523Abstract: A method for producing vinyl acetate using ethylene, acetic acid and argon containing oxygen that maximizes selectivity and minimizes ethylene loses to purge.Type: GrantFiled: December 31, 1997Date of Patent: September 14, 1999Assignee: Praxair Technology, Inc.Inventors: Vasilis Papavassiliou, Matthew Lincoln Wagner, Roger William Day