Patents by Inventor Dawid J. Duvenhage
Dawid J. Duvenhage 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: 10086366Abstract: A structurally promoted precipitated catalyst containing crystalline silica, at least one chemical promoter selected from the group consisting of alkali metals, and iron, the structurally promoted precipitated catalyst comprising maghemite and hematite catalytic phases, and exhibiting a main reduction peak temperature, as determined by TPR, in the range of from about 210° C. to about 350° C. A method of producing the structurally promoted precipitated catalyst is also provided.Type: GrantFiled: December 8, 2016Date of Patent: October 2, 2018Assignee: RES USA, LLCInventors: Dawid J. Duvenhage, Belma Demirel
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Publication number: 20170209852Abstract: A method for controllably producing a hematite-containing Fischer-Tropsch catalyst by combining an iron nitrate solution with a precipitating agent solution at a precipitating temperature and over a precipitation time to form a precipitate comprising iron phases; holding the precipitate from at a hold temperature for a hold time to provide a hematite containing precipitate; and washing the hematite containing precipitate via contact with a wash solution and filtering, to provide a washed hematite containing catalyst. The method may further comprise promoting the washed hematite containing catalyst with a chemical promoter; spray drying the promoted hematite containing catalyst; and calcining the spray dried hematite containing catalyst to provide a calcined hematite-containing Fischer-Tropsch catalyst.Type: ApplicationFiled: April 10, 2017Publication date: July 27, 2017Inventors: Dawid J. Duvenhage, Christine Schmidt, Mark Still, Khalid Azzam, Karl C. Kharas, Sara Hunegnaw, Olga Ionkina, Ray J. Huang, Harold A. Wright
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Patent number: 9669390Abstract: A method for controllably producing a hematite-containing Fischer-Tropsch catalyst by combining an iron nitrate solution with a precipitating agent solution at a precipitating temperature and over a precipitation time to form a precipitate comprising iron phases; holding the precipitate from at a hold temperature for a hold time to provide a hematite containing precipitate; and washing the hematite containing precipitate via contact with a wash solution and filtering, to provide a washed hematite containing catalyst. The method may further comprise promoting the washed hematite containing catalyst with a chemical promoter; spray drying the promoted hematite containing catalyst; and calcining the spray dried hematite containing catalyst to provide a calcined hematite-containing Fischer-Tropsch catalyst.Type: GrantFiled: February 11, 2014Date of Patent: June 6, 2017Assignee: RES USA, LLCInventors: Dawid J. Duvenhage, Christine Schmidt, Mark Still, Khalid Azzam, Karl C. Kharas, Sara Hunegnaw, Olga Ionkina, Ray J. Huang, Harold A. Wright
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Patent number: 9649610Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: GrantFiled: August 25, 2014Date of Patent: May 16, 2017Assignee: RES USA, LLCInventors: Harold A. Wright, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray J. Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Publication number: 20170100708Abstract: A structurally promoted precipitated catalyst containing crystalline silica, at least one chemical promoter selected from the group consisting of alkali metals, and iron, the structurally promoted precipitated catalyst comprising maghemite and hematite catalytic phases, and exhibiting a main reduction peak temperature, as determined by TPR, in the range of from about 210° C. to about 350° C. A method of producing the structurally promoted precipitated catalyst is also provided.Type: ApplicationFiled: December 8, 2016Publication date: April 13, 2017Inventors: Dawid J. Duvenhage, Belma Demirel
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Patent number: 9550172Abstract: A structurally promoted precipitated catalyst containing crystalline silica, at least one chemical promoter selected from the group consisting of alkali metals, and iron, the structurally promoted precipitated catalyst comprising maghemite and hematite catalytic phases, and exhibiting a main reduction peak temperature, as determined by TPR, in the range of from about 210° C. to about 350° C. A method of producing the structurally promoted precipitated catalyst is also provided.Type: GrantFiled: March 30, 2015Date of Patent: January 24, 2017Assignee: RES USA, LLCInventors: Dawid J. Duvenhage, Belma Demirel
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Patent number: 9522372Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: GrantFiled: July 2, 2013Date of Patent: December 20, 2016Assignee: RES USA, LLCInventors: Harold A. Wright, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray J. Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Publication number: 20160001267Abstract: A method for controllably producing a hematite-containing Fischer-Tropsch catalyst by combining an iron nitrate solution with a precipitating agent solution at a precipitating temperature and over a precipitation time to form a precipitate comprising iron phases; holding the precipitate from at a hold temperature for a hold time to provide a hematite containing precipitate; and washing the hematite containing precipitate via contact with a wash solution and filtering, to provide a washed hematite containing catalyst. The method may further comprise promoting the washed hematite containing catalyst with a chemical promoter; spray drying the promoted hematite containing catalyst; and calcining the spray dried hematite containing catalyst to provide a calcined hematite-containing Fischer-Tropsch catalyst.Type: ApplicationFiled: February 11, 2014Publication date: January 7, 2016Inventors: Dawid J. Duvenhage, Christine Schmidt, Mark Still, Khalid Azzam, Karl C. Kharas, Sara Hunegnaw, Olga Ionkina, Ray J. Huang, Harold A. Wright
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Publication number: 20150251167Abstract: A structurally promoted precipitated catalyst containing crystalline silica, at least one chemical promoter selected from the group consisting of alkali metals, and iron, the structurally promoted precipitated catalyst comprising maghemite and hematite catalytic phases, and exhibiting a main reduction peak temperature, as determined by TPR, in the range of from about 210° C. to about 350° C. A method of producing the structurally promoted precipitated catalyst is also provided.Type: ApplicationFiled: March 30, 2015Publication date: September 10, 2015Inventors: Dawid J. DUVENHAGE, Belma Demirel
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Patent number: 9018128Abstract: A catalyst support solution for improving the attrition resistance of a Fischer-Tropsch catalyst, the solution comprising: crystalline silica and at least one chemical promoter selected from alkali metal bases, wherein the support solution has a pH of greater than or equal to about 7. A structurally promoted catalyst comprising: crystalline silica; at least one basic chemical promoter; and iron; wherein the catalyst comprises SiO2:Fe in a ratio of from about 2:100 to about 24:100. A method of producing a structurally promoted precipitated iron catalyst, the method comprising: forming the structural support solution described above; stirring the support solution for a time to dissolve the silica in the solution; adding the support solution to a precipitated iron catalyst slurry to form an attrition resistant catalyst slurry; and drying the attrition resistant catalyst slurry to yield the structurally promoted precipitated iron catalyst.Type: GrantFiled: September 10, 2008Date of Patent: April 28, 2015Assignee: Res USA LLCInventors: Dawid J. Duvenhage, Belma Demirel
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Patent number: 8946114Abstract: A method of producing stable ferrous nitrate solution by dissolving iron in nitric acid to form a ferrous nitrate solution and maintaining the solution at a first temperature for a first time period, whereby the Fe(II) content of the ferrous nitrate solution changes by less than about 2% over a second time period. A method of producing stable Fe(II)/Fe(III) nitrate solution comprising ferrous nitrate and ferric nitrate and having a desired ratio of ferrous iron to ferric iron, including obtaining a stable ferrous nitrate solution; dissolving iron in nitric acid to form a ferric nitrate solution; maintaining the ferric nitrate solution at a second temperature for a third time period; and combining amounts of stable ferrous nitrate solution and ferric nitrate solution to produce the stable Fe(II)/Fe(III) nitrate solution. A method of preparing an iron catalyst is also described.Type: GrantFiled: May 29, 2009Date of Patent: February 3, 2015Assignee: Res USA, LLC.Inventors: Pandurang V. Nikrad, Jesse W. Taylor, Richard A. Bley, Danny M. Dubuisson, Sara L. Rolfe, Belma Demirel, Dawid J. Duvenhage, Harold A. Wright
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Patent number: 8946108Abstract: A structurally promoted, precipitated, Fischer-Tropsch catalyst that exhibits an RCAI-10 of 0-2.8 and/or produces less than 6 wt % fines after 5 hours ASTM Air Jet Attrition testing, due to formation via: preparing a nitrate solution by forming at least one metal slurry and combining the at least one metal slurry with a nitric acid solution; combining the nitrate solution with a basic solution to form a precipitate; structurally promoting the precipitate with at least one source of silicon to form a promoted mixture, wherein promoting comprises combining the precipitate with (a) silicic acid and one or more component selected from the group consisting of non-crystalline silicas, crystalline silicas, and sources of kaolin or (b) a component selected from the group consisting of non-crystalline silicas and sources of kaolin, in the absence of silicic acid; and spray drying the promoted mixture to produce catalyst having a desired particle size.Type: GrantFiled: June 2, 2014Date of Patent: February 3, 2015Assignee: RES USA, LLC.Inventors: Dawid J. Duvenhage, Belma Demirel
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Publication number: 20150023842Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: ApplicationFiled: August 25, 2014Publication date: January 22, 2015Inventors: Harold A. WRIGHT, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray J. Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Publication number: 20140274666Abstract: A structurally promoted, precipitated, Fischer-Tropsch catalyst that exhibits an RCAI-10 of 0-2.8 and/or produces less than 6 wt % fines after 5 hours ASTM Air Jet Attrition testing, due to formation via: preparing a nitrate solution by forming at least one metal slurry and combining the at least one metal slurry with a nitric acid solution; combining the nitrate solution with a basic solution to form a precipitate; structurally promoting the precipitate with at least one source of silicon to form a promoted mixture, wherein promoting comprises combining the precipitate with (a) silicic acid and one or more component selected from the group consisting of non-crystalline silicas, crystalline silicas, and sources of kaolin or (b) a component selected from the group consisting of non-crystalline silicas and sources of kaolin, in the absence of silicic acid; and spray drying the promoted mixture to produce catalyst having a desired particle size.Type: ApplicationFiled: June 2, 2014Publication date: September 18, 2014Applicant: RENTECH, INC.Inventors: Dawid J. DUVENHAGE, Belma DEMIREL
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Patent number: 8791041Abstract: A method of producing a Fischer-Tropsch catalyst by preparing a nitrate solution, wherein preparing comprises forming at least one metal slurry and combining the at least one metal slurry with a nitric acid solution; combining the nitrate solution with a basic solution to form a precipitate; promoting the precipitate to form a promoted mixture, wherein promoting comprises combining the precipitate with (a) silicic acid and one or more selected from the group consisting of non-crystalline silicas, crystalline silicas, and sources of kaolin or (b) at least one selected from non-crystalline silicas and sources of kaolin, in the absence of silicic acid; and spray drying the promoted mixture to produce catalyst having a desired particle size. Catalyst produced by the disclosed method is also described.Type: GrantFiled: May 28, 2010Date of Patent: July 29, 2014Assignee: RENTECH, Inc.Inventors: Dawid J. Duvenhage, Belma Demirel
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Publication number: 20130296448Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: ApplicationFiled: July 2, 2013Publication date: November 7, 2013Inventors: Harold A. Wright, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray J. Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Patent number: 8530366Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: GrantFiled: January 5, 2011Date of Patent: September 10, 2013Assignee: Rentech, Inc.Inventors: Harold A. Wright, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Patent number: 8138115Abstract: A method of producing an iron catalyst for catalyzing the hydrogenation of carbon monoxide is disclosed. The method comprises using a reduced amount of acid for iron dissolution compared to certain previous methods. The resulting acidic iron mixture is heated without boiling to obtain a nitrate solution having a Fe2+:Fe3+ ratio in the range of about 0.01%:99.99% to about 100%:0% (wt:wt). Iron phases are precipitated at a lower temperature compared to certain previous methods. The recovered catalyst precursor is dried and sized to form particles having a size distribution between 10 microns and 100 microns. In embodiments, the Fe2+:Fe3+ ratio in the nitric acid solution may be in the range of from about 3%:97% to about 30%:70% (wt:wt) and the calcined catalyst may comprise a maghemite:hematite ratio of about 1%:99% to about 70%:30%.Type: GrantFiled: February 26, 2010Date of Patent: March 20, 2012Assignee: Rentech, Inc.Inventors: Belma Demirel, Charles B. Benham, Jesse W. Taylor, Pandurang V. Nikrad, Sara L. Rolfe, Olga P. Ionkina, Dawid J. Duvenhage, Harold A. Wright
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Publication number: 20110313061Abstract: A method of preparing a spray dried catalyst by combining spray dried catalyst particles with wax so the spray dried catalyst particles are coated with wax, yielding wax coated catalyst particles, and shaping the wax coated catalyst to provide shaped wax coated catalyst. A method of activating Fischer-Tropsch catalyst particles containing oxides by contacting the catalyst particles with a reducing gas in an activation vessel to produce an activated catalyst, wherein contacting is performed in the absence of a liquid medium under activation conditions. A system for activating a Fischer-Tropsch catalyst containing an activation reactor configured to introduce an activation gas to a fixed or fluidized bed of the Fischer-Tropsch catalyst in the absence of a liquid medium and at least one separation device configured to separate a gas stream comprising entrained catalyst fines having an average particle size below a desired cutoff size from the activation reactor.Type: ApplicationFiled: January 5, 2011Publication date: December 22, 2011Applicant: RENTECH, INC.Inventors: Harold A. Wright, Belma Demirel, Sergio Mohedas, Bahman Rejai, Ray Huang, Deena Ferdous, Jesse W. Taylor, Dawid J. Duvenhage, Sara L. Rolfe
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Patent number: 7968611Abstract: A method of producing an iron catalyst for catalyzing the hydrogenation of carbon monoxide is disclosed. The method comprises using a reduced amount of acid for iron dissolution compared to certain previous methods. The resulting acidic iron mixture is heated without boiling to obtain a nitrate solution having a Fe2+:Fe3+ ratio in the range of about 0.01%: 99.99% to about 100%:0% (wt:wt). Iron phases are precipitated at a lower temperature compared to certain previous methods. The recovered catalyst precursor is dried and sized to form particles having a size distribution between 10 microns and 100 microns. In embodiments, the Fe2+:Fe3+ ratio in the nitric acid solution may be in the range of from about 3%:97% to about 30%:70% (wt:wt) and the calcined catalyst may comprise a maghemite:hematite ratio of about 1%:99% to about 70%:30%.Type: GrantFiled: February 26, 2010Date of Patent: June 28, 2011Assignee: Rentech, Inc.Inventors: Belma Demirel, Charles B. Benham, Jesse W. Taylor, Pandurang V. Nikrad, Sara L. Rolfe, Olga P. Ionkina, Dawid J. Duvenhage, Harold A. Wright