Patents by Inventor Rathna P. Davuluri

Rathna P. Davuluri 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: 9267083
    Abstract: Processes are provided herein for producing naphtha boiling range products with a desired sulfur content by reducing the mercaptan content of the naphtha boiling range products after the products exit a hydroprocessing stage. Due to mercaptan reversion, naphtha boiling range products that contain even small amounts of olefins can have a higher than expected sulfur content after hydroprocessing. In order to reduce or mitigate the effects of mercaptan reversion, microchannel reactors (or microreactors) can be placed in a processing system downstream of a reactor that produces a low sulfur naphtha product. The microreactors can include a coating of metals that have activity for hydrodesulfurization. By passing at least a portion of the naphtha product through the downstream microreactors, the mercaptans formed by reversion reactions can be reduced or eliminated, resulting in a naphtha product with possessing a very low sulfur content.
    Type: Grant
    Filed: December 3, 2013
    Date of Patent: February 23, 2016
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Benjamin S. Umansky, Charles R. Bolz, Anjaneya S. Kovvali, Carlos N. Lopez, Rathna P. Davuluri
  • Patent number: 9095831
    Abstract: The invention relates to a process of alkylating aromatic hydrocarbons, and more particularly a process of making paraxylene by alkylation of benzene and/or toluene with methanol and/or dimethyl ether, and to an apparatus for carrying out said process, the improvement comprising staged injection of one of the reactants, with the stages separated by structured packing so as to minimize at least one of gas phase back-mixing, by-pass phenomena, and gas bubble size.
    Type: Grant
    Filed: July 25, 2012
    Date of Patent: August 4, 2015
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Lu Han, Rathna P. Davuluri, Christopher G. Smalley, Mark P. Hagemeister, Masaaki Sugita, Joseph S. Famolaro, Robert G. Tinger
  • Publication number: 20150101406
    Abstract: In various aspects, methods and systems are provided for monitoring catalyst bed levels using multiple sensors that are temporarily installed in a reactor during catalyst loading. The multiple sensors are able to take distance measurements at substantially the same time and at predetermined time intervals so as to provide a catalyst time profile. The catalyst time profile allows an operator monitor catalyst levels during and after catalyst loading. Once catalyst loading is completed, the multiple sensors are removed from the reactor.
    Type: Application
    Filed: September 15, 2014
    Publication date: April 16, 2015
    Applicant: ExxonMobil Research and Engineering Company
    Inventors: YI EN HUANG, David C. Dankworth, Keith Wilson, Manuel S. Alvarez, Rathna P. Davuluri, Jeffrey W. Frederick, Bryan A. Patel
  • Patent number: 8999246
    Abstract: The liquid feed nozzle assemblies for a circulating fluid bed reactor comprise (i) a throttle body premixer to combine liquid feed with atomization steam upstream of a nozzle body to form a liquid feed/steam mixture comprising liquid feed droplets; (ii) a conduit connected to the venturi premixer and to a discharge nozzle body to convey a flow of the liquid/steam mixture created by the premixer to the nozzle body; (iii) a discharge nozzle connected to the flow conduit to shear the liquid feed/steam mixture to create liquid feed droplets of reduced size and (iv) a disperser at the outlet of the discharge nozzle to provide a spray jet of liquid feed having an increased surface area relative to a cylindrical jet. The nozzle assembles are particularly useful in fluid coking units using heavy oil feeds such a tar sands bitumen.
    Type: Grant
    Filed: May 17, 2011
    Date of Patent: April 7, 2015
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Edward Chan, Brian Knapper, Eberhard Mueller, Jennifer McMillan, Jonathan Tyler, Darwin Edward Kiel, Rathna P. Davuluri
  • Patent number: 8950570
    Abstract: A solids supply system having a solids deaeration zone and a solids pump zone, and a method for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a container having a passageway defined by one or more sloped walls. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.
    Type: Grant
    Filed: December 7, 2010
    Date of Patent: February 10, 2015
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: James R. Bielenberg, Michael Raterman, Rathna P. Davuluri, John W. Fulton, Steven W. Meier
  • Publication number: 20140174982
    Abstract: Processes are provided herein for producing naphtha boiling range products with a desired sulfur content by reducing the mercaptan content of the naphtha boiling range products after the products exit a hydroprocessing stage. Due to mercaptan reversion, naphtha boiling range products that contain even small amounts of olefins can have a higher than expected sulfur content after hydroprocessing. In order to reduce or mitigate the effects of mercaptan reversion, microchannel reactors (or microreactors) can be placed in a processing system downstream of a reactor that produces a low sulfur naphtha product. The microreactors can include a coating of metals that have activity for hydrodesulfurization. By passing at least a portion of the naphtha product through the downstream microreactors, the mercaptans formed by reversion reactions can be reduced or eliminated, resulting in a naphtha product with possessing a very low sulfur content.
    Type: Application
    Filed: December 3, 2013
    Publication date: June 26, 2014
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: Benjamin S. Umansky, Charles R. Bolz, Anjaneya S. Kovvali, Carlos N. Lopez, Rathna P. Davuluri
  • Patent number: 8739962
    Abstract: A solids supply systems having a solids deaeration zone and a solids pump zone, and to methods for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a roller system containing a plurality of porous roller assemblies, or a belt system containing a plurality of porous belt assemblies. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.
    Type: Grant
    Filed: December 7, 2010
    Date of Patent: June 3, 2014
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: James R. Bielenberg, Michael Raterman, Rathna P. Davuluri, John W. Fulton, Steven W. Meier
  • Publication number: 20130165724
    Abstract: The invention relates to a process of alkylating aromatic hydrocarbons, and more particularly a process of making paraxylene by alkylation of benzene and/or toluene with methanol and/or dimethyl ether, and to an apparatus for carrying out said process, the improvement comprising staged injection of one of the reactants, with the stages separated by structured packing so as to minimize at least one of gas phase back-mixing, by-pass phenomena, and gas bubble size.
    Type: Application
    Filed: July 25, 2012
    Publication date: June 27, 2013
    Inventors: Lu Han, Rathna P. Davuluri, Christopher G. Smalley, Mark Hagemeister, Masaaki Sugita, Joseph S. Famolaro, Robert G. Tinger
  • Patent number: 8399727
    Abstract: In a process for the production of para-xylene, an aromatic feedstock comprising toluene and/or benzene is reacted with methanol under alkylation conditions in a reactor in the presence of a fluidized bed of solid catalyst particles to produce a vapor phase effluent comprising para-xylene, water, unreacted toluene and/or benzene and solid catalyst fines. The vapor phase effluent is contacted with a liquid hydrocarbon quench stream under conditions to condense a minor portion of the vapor phase effluent and produce a condensate which contains at least some of the catalyst fines and which is substantially free of an aqueous phase. The condensate containing said catalyst fines is then separated from the remainder of the vapor phase effluent.
    Type: Grant
    Filed: October 6, 2010
    Date of Patent: March 19, 2013
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: James R. Lattner, Mark P. Hagemeister, Christopher Gordon Smalley, Jon Edmond Randolph Stanat, Timothy Paul Bender, Masaaki Sugita, Rathna P. Davuluri, Lu Han
  • Patent number: 8202412
    Abstract: The present invention is an improved regenerated catalyst bend assembly for a fluid catalytic cracking unit. In a preferred embodiment, the reduced elevation (“RE-bend” or “REL-bend”) regenerated catalyst return line assembly of the present invention has an outlet elevation that is lower than the inlet elevation of the RE-bend or REL-bend regenerated catalyst return line assembly, and a process for utilizing the assembly in a fluid catalytic cracking unit. The present invention is especially useful in the modification of existing fluid catalytic cracking units to lower the elevation of the outlet of the regenerated catalyst return line assembly, thereby providing needed space to increase the fluid catalytic cracking reactor riser length.
    Type: Grant
    Filed: July 17, 2007
    Date of Patent: June 19, 2012
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Brian A. Cunningham, Christopher G. Smalley, Rathna P. Davuluri, Dana W. Nouri
  • Publication number: 20120063961
    Abstract: The liquid feed nozzle assemblies for a circulating fluid bed reactor comprise (i) a throttle body premixer to combine liquid feed with atomization steam upstream of a nozzle body to form a liquid feed/steam mixture comprising liquid feed droplets; (ii) a conduit connected to the venturi premixer and to a discharge nozzle body to convey a flow of the liquid/steam mixture created by the premixer to the nozzle body; (iii) a discharge nozzle connected to the flow conduit to shear the liquid feed/steam mixture to create liquid feed droplets of reduced size and (iv) a disperser at the outlet of the discharge nozzle to provide a spray jet of liquid feed having an increased surface area relative to a cylindrical jet. The nozzle assembles are particularly useful in fluid coking units using heavy oil feeds such a tar sands bitumen.
    Type: Application
    Filed: May 17, 2011
    Publication date: March 15, 2012
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: Edward CHAN, Brian KNAPPER, Eberhard MUELLER, Jennifer MCMILLAN, Jonathan TYLER, Darwin KIEL, Rathna P. DAVULURI
  • Publication number: 20110139583
    Abstract: A solids supply systems having a solids deaeration zone and a solids pump zone, and to methods for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a roller system containing a plurality of porous roller assemblies, or a belt system containing a plurality of porous belt assemblies. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.
    Type: Application
    Filed: December 7, 2010
    Publication date: June 16, 2011
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: James R. Bielenberg, Michael Raterman, Rathna P. Davuluri, John W. Fulton, Steven W. Meier
  • Publication number: 20110139257
    Abstract: A solids supply system having a solids deaeration zone and a solids pump zone, and a method for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a container having a passageway defined by one or more sloped walls. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.
    Type: Application
    Filed: December 7, 2010
    Publication date: June 16, 2011
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: James R. Bielenberg, Michael Raterman, Rathna P. Davuluri, John W. Fulton, Steven W. Meier
  • Publication number: 20110114468
    Abstract: An improved, fouling-resistant configuration for the stripper sheds of fluid coking units comprises an inverted, open-bottomed channel with apertures spaced along the length of the channel and spaced from the apex of the channel. Preferably, the channels are of an inverted-V configuration with a downwardly extending lip provided on each side of the channel, extending from the bottom edge of each side of the channel. The stripper sheds may be positioned parallel to one another in the stripper section of the reactor vessel or, alternatively, the sheds in different tiers in the stripper section may be disposed so that the longitudinal axes of the sheds are rotated angularly relative to the sheds in other rows.
    Type: Application
    Filed: October 21, 2010
    Publication date: May 19, 2011
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: Rathna P. DAVULURI, James R. BIELENBERG, Clay R. SUTTON, Brenda A. RAICH
  • Publication number: 20110092756
    Abstract: In a process for the production of para-xylene, an aromatic feedstock comprising toluene and/or benzene is reacted with methanol under alkylation conditions in a reactor in the presence of a fluidized bed of solid catalyst particles to produce a vapor phase effluent comprising para-xylene, water, unreacted toluene and/or benzene and solid catalyst fines. The vapor phase effluent is contacted with a liquid hydrocarbon quench stream under conditions to condense a minor portion of the vapor phase effluent and produce a condensate which contains at least some of the catalyst fines and which is substantially free of an aqueous phase. The condensate containing said catalyst fines is then separated from the remainder of the vapor phase effluent.
    Type: Application
    Filed: October 6, 2010
    Publication date: April 21, 2011
    Inventors: James R. Lattner, Mark P. Hagemeister, Christopher Gordon Smalley, Jon Edmond Randolph Stanat, Timothy Paul Bender, Masaaki Sugita, Rathna P. Davuluri, Lu Han
  • Patent number: 7744746
    Abstract: This invention relates to the catalytic cracking of a hydrocarbon feed. In particular, this invention relates to an apparatus and process utilizing a catalyst stripper section of a fluid catalytic cracking (FCC) reactor with chordal trays designed to provide improved stripping of hydrocarbons from spent FCC catalyst in an FCC reactor stripping zone.
    Type: Grant
    Filed: March 28, 2007
    Date of Patent: June 29, 2010
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Brian A. Cunningham, Christopher G. Smalley, Richard C. Senior, Joseph S. Famolaro, Rathna P. Davuluri, David L. Johnson, James H. Beech, Jeffrey S. Smith
  • Patent number: 7670478
    Abstract: This invention relates to an apparatus and process for injecting a petroleum feed. More particularly, a liquid petroleum feed is atomized with a nozzle assembly apparatus in which the apparatus has injection nozzles that produce a generally flat spray pattern of finely dispersed feed. The injection nozzles are each designed such that the overall effect of the different spray patterns from the individual nozzles provides a more uniform feed coverage across the catalyst stream.
    Type: Grant
    Filed: November 3, 2005
    Date of Patent: March 2, 2010
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: George A. Swan, III, Rustom M. Billimoria, Rathna P. Davuluri, Steven S. Lowenthal, Todd R. Steffens, Christopher G. Smalley
  • Publication number: 20090020454
    Abstract: The present invention is an improved regenerated catalyst bend assembly for a fluid catalytic cracking unit. In a preferred embodiment, the reduced elevation (“RE-bend” or “REL-bend”) regenerated catalyst return line assembly of the present invention has an outlet elevation that is lower than the inlet elevation of the RE-bend or REL-bend regenerated catalyst return line assembly, and a process for utilizing the assembly in a fluid catalytic cracking unit. The present invention is especially useful in the modification of existing fluid catalytic cracking units to lower the elevation of the outlet of the regenerated catalyst return line assembly, thereby providing needed space to increase the fluid catalytic cracking reactor riser length.
    Type: Application
    Filed: July 17, 2007
    Publication date: January 22, 2009
    Inventors: Brian A. Cunningham, Christopher G. Smalley, Rathna P. Davuluri, Dana W. Nouri
  • Patent number: 7414166
    Abstract: This invention provides feed introduction devices, and processes for using same, which minimize catalyst clogging. In particular, the invention is to a feed introduction device having a first end in fluid communication with a feed source, a second end in fluid communication with a reactor and a deviation zone between the first end and the second end to deviate the flow of feed about a deviation angle from the first end toward the second end. According to the invention, the deviation angle is greater than 90 degrees.
    Type: Grant
    Filed: October 5, 2004
    Date of Patent: August 19, 2008
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: James H. Beech, Jr., Brian A. Cunningham, Christopher G. Smalley, Rathna P. Davuluri
  • Patent number: 7407572
    Abstract: This invention relates to an apparatus and process for atomizing a petroleum feed. More particularly, a liquid petroleum feed is atomized with an atomization apparatus in which the apparatus has an orifice that produces a generally flat spray pattern of finely dispersed feed prior to contacting catalyst in a fluid catalytic cracking zone. The orifice has a general aspect ratio greater than 1.0 and a ratio of perimeter length-to-cross-sectional area greater than 1.5 relative to a perimeter-to-cross-sectional area ratio of a circular orifice of equivalent area. The apparatus can be used to atomize feed injected into the cracking zone of a fluid catalytic cracker.
    Type: Grant
    Filed: June 3, 2005
    Date of Patent: August 5, 2008
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Todd R. Steffens, Thomas E. Hewitt, Rathna P. Davuluri, Enrique Feliz