Patents by Inventor Ashok S. Krishna

Ashok S. Krishna 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: 20210313835
    Abstract: Disclosed techniques include energy transfer using high-pressure vessels. Liquid is pumped into a high-pressure vessel to pressurize a gas. The gas can include air. Liquid is sprayed into the high-pressure vessel to cool the gas. Heat exchange is performed to cool the liquid before spraying the liquid into the high-pressure vessel. The spraying liquid into the top and the bottom of the high-pressure vessel is accomplished using nozzles in a top portion and nozzles in a bottom portion of the high-pressure vessel. The pressurized gas is transferred into a storage reservoir. The storage reservoir can include an underground cavern or aquifer. Gas from the storage reservoir is delivered to drive a turbine to recover stored energy. The extracting gas from the storage reservoir is accomplished using an additional high-pressure vessel. Heat exchange is performed to warm the liquid before spraying the liquid into the additional high-pressure vessel.
    Type: Application
    Filed: June 18, 2021
    Publication date: October 7, 2021
    Inventors: Shankar Ramamurthy, Ashok S. Krishna
  • Patent number: 5616237
    Abstract: A fluid catalytic cracking unit equipped with multiple feed injection points along the length of the riser is operated such that portions of the same fresh feed are charged to different feed injection points. Preferably, the hydrocarbon fresh feed can be split into two or more non-distinct fractions, with one fraction charged to the bottom injection point along the length of the riser reactor, and the remaining fractions charged to injection points progressively higher up along the length of the riser reactor with the temperature of the upper injection feed fractions being different from that of the lowest injection point fraction prior to entry into the FCC riser reactor. Hydrocarbon products from the cracking process can be recycled to one or more of the various injection points along the length of the riser.
    Type: Grant
    Filed: April 1, 1996
    Date of Patent: April 1, 1997
    Assignee: Chevron Research and Technology Company, A Division of Chevron U.S.A. Inc.
    Inventors: Ashok S. Krishna, Robert C. Skocpol, Lewis A. Frederickson
  • Patent number: 5098554
    Abstract: A fluid catalytic cracking unit equipped with multiple feed injection points along the length of the riser is operated such that all of the fresh feed is charged to one of different feed injection points, depending on the ratio of light distillate (gasoline) to middle distillate (light catalytic gas oil) that is desired in the product slate. When all of the fresh feed is charged to one of the upper injection points in the riser in order to increase middle distillate yield, the unconverted slurry oil (650.degree. F.+material) can be recycled to a location below the injection point of the fresh feed so as to increase conversion to middle distillate while lowering the activity of the catalyst (via coke deposition) for single pass conversion of the fresh feed. Steam in excess of levels typically employed for dispersion is used at the bottom of the riser to lift the regenerated catalyst up to the feed injection points.
    Type: Grant
    Filed: September 26, 1990
    Date of Patent: March 24, 1992
    Assignee: Chevron Research Company
    Inventors: Ashok S. Krishna, Alan R. English, Michael F. Raterman
  • Patent number: 4997545
    Abstract: A method for selective alteration of yield structures in fluid catalytic cracking units toward more middle distillate (light catalytic gas oil) and less light distillate (gasoline) by the addition of basic nitrogen compounds.
    Type: Grant
    Filed: December 6, 1985
    Date of Patent: March 5, 1991
    Assignee: Chevron Research Company
    Inventors: Ashok S. Krishna, Dennis C. Kowalczyk
  • Patent number: 4980045
    Abstract: A process is provided for the pretreatment of heavy oil feeds to demetalate and remove coke precursors. Inert, sorbent material is utilized in a reaction zone to effect the contaminant removal and is cycled to a regeneration zone. The sorbent also adsorbs sulfur oxides produced in a regeneration zone which are then cycled back to the reaction zone, converted to hydrogen sulfide, and removed from the system. The preferred sorbent material is high surface area alumina, having an average surface area in the circulating inventory of greater than 100 m.sup.2 /g.
    Type: Grant
    Filed: August 2, 1988
    Date of Patent: December 25, 1990
    Assignee: Chevron Research Company
    Inventors: Ashok S. Krishna, David J. Bott, Theresa A. Pecoraro
  • Patent number: 4964979
    Abstract: Contaminant metals in hydrocarbon oils such as nickel, vanadium and iron deposit on inert sorbents during pretreatment of the oils in a fluidized reactor-regenerator system, and catalyze dehydrogenation reactions contributing to excessive coke and gas make. The dehydrogenation activity of the said contaminant metals is suppressed by depositing minor amounts of a bismuth-containing passivating agent on the inert solids, desirably, at a weight ratio of bismuth to nickel equivalents (nickel+0.2 vanadium+0.1 iron) of about 0.01:1 to about 1:1. The passivating agent can consist of mixtures of compounds of bismuth and antimony, and bismuth and tin, with the weight ratio of bismuth to antimony in the range of about 0.01:1 to about 100:1, and weight ratio of bismuth to tin in the range of about 0.01:1 to about 100:1.
    Type: Grant
    Filed: August 7, 1989
    Date of Patent: October 23, 1990
    Inventors: Ashok S. Krishna, Ramamoorthy Periaswamy
  • Patent number: 4869807
    Abstract: A fluid catalytic cracking unit equipped with multiple feed injection points along the length of the riser is operated such that portions of the same fresh feed are charged to different feed injection points. Preferably, the hydrocarbon fresh feed can be split into two or more non-distinct fractions, with one fraction charged to the bottom injection point along the length of the riser reactor, and the remaining fractions charged to injection points progressively higher up along the length of the riser reactor. Unconverted slurry oil boiling above 650.degree. F. can be recycled to one or more of the various injection points along the length of the riser.
    Type: Grant
    Filed: June 26, 1987
    Date of Patent: September 26, 1989
    Assignee: Chevron Research Company
    Inventor: Ashok S. Krishna
  • Patent number: 4784752
    Abstract: Poisoning of a cracking catalyst by contaminant metals such as nickel, vanadium and iron during fluid catalytic cracking of hydrocarbon charge stock containing the contaminant metals is suppressed by depositing minor amounts of a bismuth-containing passivating agent on the catalyst, desirably, a weight ratio of bismuth to nickel equivalents (nickel+0.2 vanadium+0.1 iron) of about 0.01:1 to about 1:1. The passivating agent can also comprise mixtures of compounds of bismuth and antimony, bismuth and tin.
    Type: Grant
    Filed: May 5, 1987
    Date of Patent: November 15, 1988
    Assignee: Chevron Research Company
    Inventors: Periaswamy Ramamoorthy, Ashok S. Krishna
  • Patent number: RE36403
    Abstract: A fluid catalytic cracking unit equipped with multiple feed injection points along the length of the riser is operated such that portions of the same fresh feed are charged to different feed injection points. Preferably, the hydrocarbon fresh feed can be split into two or more non-distinct fractions, with one fraction charged to the bottom injection point along the length of the riser reactor, and the remaining fractions charged to injection points progressively higher up along the length of the riser reactor. Unconverted slurry oil boiling above 650.degree. F. can be recycled to one or more of the various injection points along the length of the riser.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: November 23, 1999
    Assignee: Chevron Research and Technology Company
    Inventor: Ashok S. Krishna