Patents by Inventor Joanna L. Duncan

Joanna L. Duncan 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: 7052662
    Abstract: A process and apparatus for removing SO2, NO, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an alkali scrubbing solution, and removing any alkali aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to oxidized mercury and removing it in the scrubbing solution and wet electrostatic precipitator. Alkali sulfates, which are valuable fertilizers, can be withdrawn from the rubbing solution.
    Type: Grant
    Filed: June 28, 2002
    Date of Patent: May 30, 2006
    Assignee: Powerspan Corp.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Patent number: 7048899
    Abstract: A process and apparatus for removing SO2, NO, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an ammonia, ammonium hydroxide, alkali hydroxide or carbonate scrubbing solution, regenerating the scrubbing solution with limestone, and removing any particulate matter and aerosols generated by the scrubbing step in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to oxidized Hg and removing it in the wet electrostatic precipitator. The scrubbing solution is preferably regenerated with limestone or magnesium, and results in a Group II sulfite or sulfate that can be recovered and sold, or landfilled.
    Type: Grant
    Filed: August 12, 2002
    Date of Patent: May 23, 2006
    Assignee: Powerspan Corp.
    Inventors: Francis R. Alix, Joanna L. Duncan, Christopher R. McLarnon
  • Patent number: 6991771
    Abstract: A process and apparatus for removing SO2, NO, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an ammonia scrubbing solution, and removing any ammonia aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to HgO and removing it in the wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: January 31, 2006
    Assignee: Powerspan Corp.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Patent number: 6936231
    Abstract: A process and apparatus for removing SO2, O, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an ammonia scrubbing solution, and removing any ammonia aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to HgO and removing it in the wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Grant
    Filed: December 6, 2001
    Date of Patent: August 30, 2005
    Assignee: Powerspan Corp.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Publication number: 20040105802
    Abstract: A process and apparatus for removing S02, NO, and N02 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to N02, scrubbing the S02, NO, and N02 with an ammonia scrubbing solution, and removing any ammonia aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to HgO and removing it in the wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Application
    Filed: December 5, 2003
    Publication date: June 3, 2004
    Applicant: POWERSPAN CORP.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Publication number: 20030175190
    Abstract: A process and apparatus for removing SO2, O, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an ammonia scrubbing solution, and removing any ammonia aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to HgO and removing it in the wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Application
    Filed: December 6, 2001
    Publication date: September 18, 2003
    Applicant: Powerspan Corp.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Patent number: 6605263
    Abstract: A process and apparatus for removing SO2 from a gas stream having the steps of scrubbing the SO2 with an ammonia scrubbing solution and removing any aerosols generated by the scrubbing in a wet electrostatic precipitator. The scrubbing solution is maintained at a pH between 6 and 8 to increase the speed of absorption of SO2, to Increase the ratio of sulfite to bisulfite which also facilitates the oxidation of SO2, and to avoid the need to use exotic, corrosion resistant alloys. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: August 12, 2003
    Assignee: Powerspan Corp.
    Inventors: Francis R. Alix, Joanna L. Duncan, Christopher R. McLarnon
  • Publication number: 20030108466
    Abstract: A process and apparatus for removing SO2, NO, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an ammonia, ammonium hydroxide, alkali hydroxide or carbonate scrubbing solution, regenerating the scrubbing solution with limestone, and removing any particulate matter and aerosols generated by the scrubbing step in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to oxidized Hg and removing it in the wet electrostatic precipitator. The scrubbing solution is preferably regenerated with limestone or magnesium, and results in a Group II sulfite or sulfate that can be recovered and sold, or landfilled.
    Type: Application
    Filed: August 12, 2002
    Publication date: June 12, 2003
    Applicant: Powerspan Corp.
    Inventors: Francis R. Alix, Joanna L. Duncan, Christopher R. McLarnon
  • Publication number: 20030108472
    Abstract: A process and apparatus for removing SO2, NO, and NO2 from a gas stream having the steps of oxidizing a portion of the NO in the flue gas stream to NO2, scrubbing the SO2, NO, and NO2 with an alkali scrubbing solution, and removing any alkali aerosols generated by the scrubbing in a wet electrostatic precipitator. The process can also remove Hg by oxidizing it to oxidized mercury and removing it in the scrubbing solution and wet electrostatic precipitator. Alkali sulfates, which are valuable fertilizers, can be withdrawn from the rubbing solution.
    Type: Application
    Filed: June 28, 2002
    Publication date: June 12, 2003
    Applicant: Powerspan Corp.
    Inventors: Joanna L. Duncan, Christopher R. McLarnon, Francis R. Alix
  • Publication number: 20030108469
    Abstract: A process and apparatus for removing SO2 from a gas stream having the steps of scrubbing the SO2 with an ammonia scrubbing solution and removing any aerosols generated by the scrubbing in a wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.
    Type: Application
    Filed: January 31, 2002
    Publication date: June 12, 2003
    Applicant: Powerspan Corp.
    Inventors: Francis R. Alix, Joanna L. Duncan, Christopher R. McLarnon