Patents by Inventor Pak C. Leung

Pak C. Leung 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).

  • Patent number: 7410928
    Abstract: The instant invention is directed to the preparation of a catalyst composition suitable for the hydroconversion of heavy oils. The catalyst composition is prepared by a series of steps, involving mixing a Group VIB metal oxide particularly molybdenum oxide and aqueous ammonia to form an aqueous mixture, and sulfiding the mixture to form a slurry. The slurry is then promoted with a Group VIII metal. Subsequent steps involve mixing the slurry with a hydrocarbon oil and combining the resulting mixture with hydrogen gas and a second hydrocarbon oil having a lower viscosity than the first oil. An active catalyst composition is thereby formed.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: August 12, 2008
    Assignee: Chevron U.S.A. Inc.
    Inventors: Kaidong Chen, Pak C. Leung, Bruce E. Reynolds
  • Patent number: 7238273
    Abstract: The instant invention is directed to a process for upgrading heavy oils using a slurry composition. The slurry composition is prepared by a series of steps, involving mixing a Group VIB metal oxide and aqueous ammonia to form an aqueous mixture, and sulfiding the mixture to form a slurry. The slurry is then promoted with a Group VIII metal. Subsequent steps involve mixing the slurry with a hydrocarbon oil and combining the resulting mixture with hydrogen gas and a second hydrocarbon oil having a lower viscosity than the first oil. An active catalyst composition is thereby formed.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: July 3, 2007
    Assignee: Chevron U.S.A. Inc
    Inventors: Kaidong Chen, Pak C. Leung, Bruce E. Reynolds
  • Patent number: 7214309
    Abstract: The instant invention is directed to a process for upgrading heavy oils using a slurry composition. The slurry composition is prepared in a series of steps, involving mixing a Group VIB metal oxide with aqueous ammonia to form an aqueous mixture and sulfiding the mixture to form a slurry. The slurry is then promoted with a Group VIII metal compound. Subsequent steps involve mixing the slurry with a hydrocarbon oil, and combining the resulting mixture with hydrogen gas (under conditions which maintain the water in a liquid phase) to produce the active slurry catalyst.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: May 8, 2007
    Assignee: Chevron U.S.A. Inc
    Inventors: Kaidong Chen, Pak C. Leung, Bruce E. Reynolds, Julie Chabot
  • Patent number: 7074740
    Abstract: An improved catalyst for hydrodesulfurization of heavy feedstocks is disclosed. The catalyst is adopted for on-stream catalyst replacement in upflow processing units. It is characterized by a smaller peak pore diameter than general purpose hydrotreating catalysts.
    Type: Grant
    Filed: July 2, 2002
    Date of Patent: July 11, 2006
    Assignee: Chevron U.S.A. Inc.
    Inventors: Kirk R. Gibson, Richard Threlkel, Pak C. Leung
  • Publication number: 20040004030
    Abstract: An improved catalyst for hydrodesulfurization of heavy feedstocks is disclosed. The catalyst is adopted for on-stream catalyst replacement in upflow processing units. It is characterized by a smaller peak pore diameter than general purpose hydrotreating catalysts.
    Type: Application
    Filed: July 2, 2002
    Publication date: January 8, 2004
    Inventors: Kirk R. Gibson, Richard Threlkel, Pak C. Leung
  • Patent number: 6554994
    Abstract: A reactor system and process for hydrotreating a heavy feedstock contaminated with metals sulfur and carbon residue using an upflow fixed bed reactor with at least two catalyst layers having different hydrogenation activity.
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: April 29, 2003
    Assignee: Chevron U.S.A. Inc.
    Inventors: Bruce E. Reynolds, Fred W. Lam, Julie Chabot, Fernando J. Antezana, Robert Bachtel, Kirk R. Gibson, Richard Threlkel, Pak C. Leung
  • Publication number: 20020043483
    Abstract: Catalyst particles are presulfided in a treatment zone separate from a hydroconversion reaction zone. The presulfided catalyst is then added to a substantially packed bed of catalyst in the hydroconversion reaction zone at reaction pressure, so that the reactor is not shut down to replace catalyst. The presulfiding process is particularly beneficial for use in moving bed reactors for heavy oil conversion.
    Type: Application
    Filed: April 20, 2001
    Publication date: April 18, 2002
    Inventors: Pak C. Leung, David E. Earls, Bruce E. Reynolds, David R. Johnson, Robert W. Bachtel, Harold J. Trimble