Patents by Inventor Prasad Y. Duggirala

Prasad Y. Duggirala 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: 20100006242
    Abstract: A composition and method for deinking is disclosed. The composition and method contain an activated magnesium silicate or a magnesium silicate.
    Type: Application
    Filed: July 9, 2008
    Publication date: January 14, 2010
    Inventors: Prasad Y. Duggirala, Michael J. Murcia
  • Patent number: 7504478
    Abstract: Methods of increasing the yield of tall oil soap from a black liquor are provided. In an embodiment, the method comprises adding a separation aid to the black liquor. The separation aid comprises alkyl alcohol alkoxylates of formula RO[(CH2CHCH3O)x(CH2CH2O)y]M and combinations thereof, wherein R is straight or branched alkyl of about 8 to about 22 carbon atoms; x is 1 to about 20; y is about 20 to about 80 and M is H or an alkali metal.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: March 17, 2009
    Assignee: Nalco Company
    Inventors: James J. Svarz, Prasad Y. Duggirala, Grady E. Worley
  • Publication number: 20080277083
    Abstract: A method of monitoring and inhibiting scale precipitation and deposition from spent liquor in pulp mill evaporators and concentrators is disclosed. The method includes connecting a black liquor deposition monitor to a pulp mill evaporator or concentrator and measuring the thermal conductivity on the outer surface of the monitor. A controller interprets the measured thermal conductivity and determines a level of scale deposition. If the level of scale deposition is above a predetermined level, the controller is operable to introduce a scale-inhibiting composition to the spent liquor. The scale-inhibiting composition may include organic polycarboxylic acids; organic fatty acids; low molecular weight and polymeric aromatic acids; organic acid esters, anhydrides, and amides; low molecular weight and polymeric aliphatic and aromatic sulfonic acids; and low molecular weight and polymeric amines; and any combinations.
    Type: Application
    Filed: May 10, 2007
    Publication date: November 13, 2008
    Inventors: Sergey M. Shevchenko, Prasad Y. Duggirala, Dmitri L. Kouznetsov
  • Publication number: 20080182967
    Abstract: Methods of increasing the yield of tall oil soap from a black liquor are provided. In an embodiment, the method comprises adding a separation aid to the black liquor. The separation aid comprises alkyl alcohol alkoxylates of formula RO[(CH2CHCH3O)x(CH2CH2O)y]M and combinations thereof, wherein R is straight or branched alkyl of about 8 to about 22 carbon atoms; x is 1 to about 20; y is about 20 to about 80 and M is H or an alkali metal.
    Type: Application
    Filed: January 26, 2007
    Publication date: July 31, 2008
    Inventors: James J. Svarz, Prasad Y. Duggirala, Grady E. Worley
  • Publication number: 20080105392
    Abstract: This invention provides a composition and method for improving a mechanical pulping process by decreasing freeness and amount of shives, providing energy and chemical savings, and enhancing brightness and mechanical strength of a paper product made from a pulp material in the process. The composition includes formulations, such as surfactants, chelants, hydrotropes, reductive and oxidative pulp modifiers, and pH-controlling chemicals. The method includes selectively introducing these formulations to the pulp material in the mechanical pulping process.
    Type: Application
    Filed: November 3, 2006
    Publication date: May 8, 2008
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko
  • Patent number: 7351764
    Abstract: Mechanical or Chemical pulp is treated with about 0.01 weight % to about 5 weight % of a Mixture. The Mixture is water; diethylenetriaminepentakis(methyl)phosphonic acid or its known salts; polyacrylic acid or its known salts; and optionally one or more inert compounds. This Mixture acts to either maintain the brightness level of the pulp at the target level or to increase the brightness level of the pulp. In addition the Mixture allows for maintaining the pulp at the target level of brightness even when the amounts of other ingredients, such as hydrogen peroxide, hydrosulfite, sodium silicate and magnesium, that are typically added to the pulp, are reduced.
    Type: Grant
    Filed: March 31, 2004
    Date of Patent: April 1, 2008
    Assignee: Nalco Company
    Inventors: Sergey M. Shevchenko, Prasad Y. Duggirala
  • Publication number: 20080017337
    Abstract: Oxidative compositions and processes that preserve and enhance the brightness and improve color of pulp or paper when applied during different stages of the papermaking process are identified. The oxidative composition and method maintains and/or enhances brightness, prevents yellowing, and enhances the performance of paper products. Used in combination with optical brighteners and/or chelants the oxidative agents produce a synergistic effect not previously identified in the paper process.
    Type: Application
    Filed: July 21, 2006
    Publication date: January 24, 2008
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Katherine M. Broadus
  • Patent number: 7229525
    Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed. A method to enhance delignification in a Chemical pulp comprising adding an organic sulfide chelant is also described and claimed.
    Type: Grant
    Filed: May 3, 2005
    Date of Patent: June 12, 2007
    Assignee: Nalco Company
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
  • Patent number: 7081183
    Abstract: This invention is a method of reducing the resin content of chemical pulps comprising heating wood chips in an aqueous alkaline medium in the presence of an effective deresinating amount of an alkyl alcohol alkoxylate of formula RO[(CH2CHCH3O)x(CH2CH2O)y]M wherein R is C4 to C40 alkyl; x is 1–50; y is 0–100 and M is H or an alkali metal, a cooking liquor comprising sodium hydroxide and sodium sulfite and the alkyl alcohol alkoxylate and a deresinated pulp prepared according to the method.
    Type: Grant
    Filed: July 23, 2002
    Date of Patent: July 25, 2006
    Assignee: Nalco Company
    Inventors: Prasad Y Duggirala, James J. Svarz
  • Patent number: 6942782
    Abstract: A method and apparatus for measuring the deposit forming propensity of a continuously flowing fluid having a bulk pH of about 1 to about 12 comprising measuring the rate at which deposit forms on a quartz crystal microbalance having a top side comprising a working electrode in contact with the fluid and a bottom side isolated from the fluid, wherein the pH of the fluid proximate to the microbalance is controlled electrochemically at about 1 to about 14 by applying to the working electrode a cathodic current of about ?0.001 to about ?100 mA/cm2 or an anodic current of from about 0.001 to about 100 mA/cm2 and wherein the working electrode is coated with or made of a conductive material on which the rate of hydrogen gas evolution is at least 10 times lower than on a gold cathode in acidic solution.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: September 13, 2005
    Assignee: Nalco Company
    Inventors: Sergey M. Shevchenko, Dmitri L. Kouznetsov, Prasad Y. Duggirala
  • Publication number: 20040154761
    Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed.
    Type: Application
    Filed: February 6, 2004
    Publication date: August 12, 2004
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
  • Patent number: 6702921
    Abstract: A method to enhance brightness in Chemical and Mechanical bleached pulps comprising adding an organic sulfide chelant to the Chemical and Mechanical pulp.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: March 9, 2004
    Assignee: Ondeo Nalco Company
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
  • Publication number: 20040016526
    Abstract: This invention is a method of reducing the resin content of chemical pulps comprising heating wood chips in an aqueous alkaline medium in the presence of an effective deresinating amount of an alkyl alcohol alkoxylate of formula RO[(CH2CHCH3O)x(CH2CH2O)y]M wherein R is C4 to C40 alkyl; x is 1-50; y is 0-100 and M is H or an alkali metal, a cooking liquor comprising sodium hydroxide and sodium sulfite and the alkyl alcohol alkoxylate and a deresinated pulp prepared according to the method.
    Type: Application
    Filed: July 23, 2002
    Publication date: January 29, 2004
    Inventors: Prasad Y. Duggirala, James J. Svarz
  • Publication number: 20030085008
    Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed.
    Type: Application
    Filed: May 1, 2001
    Publication date: May 8, 2003
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
  • Publication number: 20030070943
    Abstract: A method and apparatus for measuring the deposit forming propensity of a continuously flowing fluid having a bulk pH of about 1 to about 12 comprising measuring the rate at which deposit forms on a quartz crystal microbalance having a top side comprising a working electrode in contact with the fluid and a bottom side isolated from the fluid, wherein the pH of the fluid proximate to the microbalance is controlled electrochemically at about 1 to about 14 by applying to the working electrode a cathodic current of about −0.001 to about −100 mA/cm2 or an anodic current of from about 0.001 to about 100 mA/cm2 and wherein the working electrode is coated with or made of a conductive material on which the rate of hydrogen gas evolution is at least 10 times lower than on a gold cathode in acidic solution.
    Type: Application
    Filed: April 22, 2002
    Publication date: April 17, 2003
    Inventors: Sergey M. Shevchenko, Dmitri L. Kouznetsov, Prasad Y. Duggirala
  • Patent number: 6527914
    Abstract: Methods to enhance the brightness and brightness stability of paper and paperboard made with Mechanical Pulp are described and claimed. The method involves applying a Penetrant Compound to paper or paperboard in an amount from about 0.001 percent to about 1 percent by weight. The Penetrant Compound can have one component that is either polyamino polyether methylene phosphonate (PAPEMP) and &agr;-glucoheptonic-&ggr;-lactone (GL); or the Penetrant Compound can have two components, where the first component is selected from the group consisting of PAPEMP and GL and the second component is an inorganic salt; or the Penetrant Compound can have three components where one component is selected from the group consisting of PAPEMP and GL, the second component is selected from the group consisting of 3,5-dimethylperhydrothiadiazine-2-thion and dialkyldithiocarbamates and the third component is an inorganic salt.
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: March 4, 2003
    Assignee: Ondeo Nalco Company
    Inventors: Sergey M. Shevchenko, Prasad Y. Duggirala
  • Publication number: 20020144950
    Abstract: Compositions and methods for inhibiting scale are provided. Pursuant to the present invention, a composition for inhibiting scale is provided that includes a carbohydrate polymer having both nitrogen-containing groups and carboxyl groups. The nitrogen-containing groups include amino groups, amido groups and mixtures thereof. The present invention has been found useful for inhibiting scale in industrial waters, such as, pulp bleach plant process waters which contain calcium oxalate and barium sulfate scale.
    Type: Application
    Filed: January 31, 2001
    Publication date: October 10, 2002
    Inventors: Sergey M. Shevchenko, Prasad Y. Duggirala
  • Patent number: 6440327
    Abstract: Compositions and methods for inhibiting scale are provided. Pursuant to the present invention, a composition for inhibiting scale is provided that includes a carbohydrate polymer having both nitrogen-containing groups and carboxyl groups. The nitrogen-containing groups include amino groups, amido groups and mixtures thereof. The present invention has been found useful for inhibiting scale in industrial waters, such as, pulp bleach plant process waters which contain calcium oxalate and barium sulfate scale.
    Type: Grant
    Filed: January 31, 2001
    Date of Patent: August 27, 2002
    Assignee: Ondeo Nalco Company
    Inventors: Sergey M. Shevchenko, Prasad Y. Duggirala
  • Patent number: 6375829
    Abstract: This invention is directed to a method and apparatus for measuring the rate of calcium oxalate scale formation in a continuously flowing solution having a pH of from about 2 to about 3 comprising measuring the rate of deposition of calcium oxalate scale from the solution on to a quartz crystal microbalance having a top side comprising a working electrode in contact with the solution and a second, bottom side isolated from the solution, wherein the pH of the solution proximate to the microbalance is measured using a pH measuring module and is controlled electrochemically at from about 3.5 to about 9 and wherein the working electrode is coated with or made of a conductive material on which the intensive evolution of hydrogen gas proceeds at potentials more negative than those necessary to achieve a pH of 3.5-9 proximate to the microbalance.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: April 23, 2002
    Assignee: Nalco Chemical Company
    Inventors: Sergey M. Shevchenko, Dmitri L. Kouznetsov, Prasad Y. Duggirala