Patents by Inventor Shivaji Sircar

Shivaji Sircar 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: 9649589
    Abstract: A oxygen concentrating system comprising an adsorption column having a first end and a second end, a shell enclosing the column and defining a product gas storage space between the column and the shell, a product conduit connecting the product gas storage space to a product output point, a first conduit comprising at least one first valve having at least a first and second configuration, in the first configuration, compressed air flows from the feed point to the first end, and, in the second configuration, waste gas flows from the first end to the waste point, and a second conduit comprising at least one second valve having at least a first and second configuration, in the first configuration, the product gas flows from the product gas storage space to the second end, and, in the second configuration, the product gas flows from the second end to the storage space.
    Type: Grant
    Filed: February 21, 2014
    Date of Patent: May 16, 2017
    Assignee: Lehigh University
    Inventors: Rama Rao Vemula, Shivaji Sircar, Mayuresh Kothare
  • Publication number: 20150375162
    Abstract: A oxygen concentrating system comprising an adsorption column having a first end and a second end, a shell enclosing the column and defining a product gas storage space between the column and the shell, a product conduit connecting the product gas storage space to a product output point, a first conduit comprising at least one first valve having at least a first and second configuration, in the first configuration, compressed air flows from the feed point to the first end, and, in the second configuration, waste gas flows from the first end to the waste point, and a second conduit comprising at least one second valve having at least a first and second configuration, in the first configuration, the product gas flows from the product gas storage space to the second end, and, in the second configuration, the product gas flows from the second end to the storage space.
    Type: Application
    Filed: February 21, 2014
    Publication date: December 31, 2015
    Applicant: LEHIGH UNIVERSITY
    Inventors: RAMA RAO VEMULA, SHIVAJI SIRCAR, MAYURESH KOTHARE
  • Patent number: 8226745
    Abstract: Provided herein are new compact and miniature oxygen concentrator apparatus, as well as methods incorporating use of the apparatus. The apparatus and methods utilize selected cycle times, adsorbent specifications and novel conditions to produce a fast Pressure Swing Adsorption (“PSA”) system. The oxygen concentrator apparatus and methods herein have significant utility in the fields of biotechnology, engineering, and medicine. A particularly advantageous use of this invention is as a “snap on” portable oxygen concentrator, where piped compressed air is already available such as in civil and military hospitals, ambulances, air craft cabins, mobile fish tanks, etc. Those embodiments eliminate the need for dedicated moving machinery (blower, compressor, vacuum pump) normally associated with a conventional PSA oxygen concentrator.
    Type: Grant
    Filed: April 28, 2010
    Date of Patent: July 24, 2012
    Assignee: Lehigh University
    Inventors: Chai Siew-Wah, Shivaji Sircar, Mayuresh V. Kothare
  • Publication number: 20100300285
    Abstract: Provided herein are new compact and miniature oxygen concentrator apparatus, as well as methods incorporating use of the apparatus. The apparatus and methods utilize selected cycle times, adsorbent specifications and novel conditions to produce a fast Pressure Swing Adsorption (“PSA”) system. The oxygen concentrator apparatus and methods herein have significant utility in the fields of biotechnology, engineering, and medicine. A particularly advantageous use of this invention is as a “snap on” portable oxygen concentrator, where piped compressed air is already available such as in civil and military hospitals, ambulances, air craft cabins, mobile fish tanks, etc. Those embodiments eliminate the need for dedicated moving machinery (blower, compressor, vacuum pump) normally associated with a conventional PSA oxygen concentrator.
    Type: Application
    Filed: April 28, 2010
    Publication date: December 2, 2010
    Applicant: LEHIGH UNIVERSITY
    Inventors: Chai Siew-Wah, Shivaji Sircar, Mayuresh V. Kothare
  • Publication number: 20030037672
    Abstract: Temperature swing adsorption of contaminants such as water and air from a gas stream such as air is conducted using adsorbent packed in tube side passages of a tube and shell heat exchanger adsorber. After a period of adsorption heating fluid is passed through the shell side passage of the adsorber during regeneration and upon exiting from the adsorber is recycled via a heater back into the shell side of the adsorber. During a cooling phase of the regeneration, a cooling fluid is passed through the shell side passage of the adsorber.
    Type: Application
    Filed: August 27, 2001
    Publication date: February 27, 2003
    Inventor: Shivaji Sircar
  • Patent number: 6468328
    Abstract: A process for producing an oxygen enriched product includes: (a) providing a gas separation apparatus having at least one bed containing a mixture of at least two different nitrogen selective adsorbents, wherein the at least one bed is free of lithium cations; (b) feeding a feed gas containing oxygen and nitrogen into the gas separation apparatus to contact the at least one bed; and (c) recovering from the gas separation apparatus the oxygen enriched product. The process is preferably performed above ambient temperature and/or in a simplified four-step cycle.
    Type: Grant
    Filed: December 18, 2000
    Date of Patent: October 22, 2002
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, William Emil Waldron
  • Publication number: 20020108494
    Abstract: A process for producing an oxygen enriched product includes: (a) providing a gas separation apparatus having at least one bed containing a mixture of at least two different nitrogen selective adsorbents, wherein the at least one bed is free of lithium cations; (b) feeding a feed gas containing oxygen and nitrogen into the gas separation apparatus to contact the at least one bed; and (c) recovering from the gas separation apparatus the oxygen enriched product. The process is preferably performed above ambient temperature and/or in a simplified four-step cycle.
    Type: Application
    Filed: December 18, 2000
    Publication date: August 15, 2002
    Inventors: Shivaji Sircar, William Emil Waldron
  • Patent number: 6328945
    Abstract: A process for producing carbon monoxide (CO) by reforming methane and steam in the presence of a reforming catalyst to produce a reformate product enriched in CO, carbon dioxide (CO2) and hydrogen. CO2 in the enriched reformate is shifted to CO in an integrated sorption enhanced reaction (SER) cycle which employs a series of cyclic steps to facilitate reaction of CO2 and hydrogen at high conversion and to produce a CO-enriched product obtained at reactor feed pressure and at essentially constant flow rate. A series of adsorbent regeneration step including depressurization, purging and product pressurization are used to desorb water which is selectively adsorbed by the adsorbent during the shift reaction and to prepare the reactor for a subsequent process cycle.
    Type: Grant
    Filed: April 8, 1996
    Date of Patent: December 11, 2001
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Jeffrey Raymond Hufton, Shivaji Sircar, William Frederick Baade, Joseph Michael Abrardo, Madhu Anand
  • Patent number: 6322612
    Abstract: A pressure or vacuum swing adsorption process and apparatus are used for the separation and recovery of certain gaseous components, such as carbon dioxide from hot gas mixtures containing water vapor. The process comprises introducing the feed gas mixture at an elevated temperature into a feed end of an adsorber column containing an adsorbent. The adsorbent preferentially adsorbs at least one adsorbable component. An adsorber effluent, depleted of the at least one adsorbable component, is withdrawn from a product end of the adsorber column. The adsorber column is depressurized below atmospheric pressure and then purged with steam to withdraw an effluent comprising a mixture of the at least one adsorbable component and H2O. Next, the adsorber column is pressurized by introducing a gas that is depleted of the at least one adsorbable component. The steps are repeated in a cyclic manner.
    Type: Grant
    Filed: December 23, 1999
    Date of Patent: November 27, 2001
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, Catherine Marie Anne Golden
  • Patent number: 6312658
    Abstract: The present invention is a process for producing an essentially pure carbon monoxide (CO) product and an essentially pure hydrogen product by reforming a hydrocarbon such as methane and steam in the presence of a reforming catalyst to produce a reformate product enriched in CO, carbon dioxide and hydrogen. The reformate is subjected to an integrated series of separation steps and carbon dioxide present in a portion of the waste effluent recovered from such series of spearation steps is shifted to CO in an integrated sorption enhanced reaction (SER) process.
    Type: Grant
    Filed: April 8, 1996
    Date of Patent: November 6, 2001
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Jeffrey Raymond Hufton, Shivaji Sircar, William Frederick Baade, Joseph Michael Abrardo, Madhu Anand
  • Patent number: 6303092
    Abstract: The present invention is a process for operating equilibrium controlled reactions in continuous mode wherein a feedstock is reacted in a plurality of reactors containing an admixture of a desired process catalyst and an adsorbent to form a product which is selectively adsorbed by the adsorbent and an admixture containing a product which is withdrawn from the reactor. A series of separation steps is used to desorb the product which is selectively adsorbed by the adsorbent and to prepare the reactor for a subsequent process cycle. The process utilizes a novel series of adsorption and desorption steps to collect the less selectively adsorbed product in substantially pure form under relatively constant flow rate at feedstock pressure.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: October 16, 2001
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Madhu Anand, Shivaji Sircar, Brian Thomas Carvill
  • Patent number: 6146447
    Abstract: Process and single-bed pressure swing adsorption system for separating gas mixtures, especially air. The process includes a simultaneous countercurrent product purge and partial product repressurization step which shortens cycle time and improves overall system operation.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: November 14, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, Tarik Naheiri, Jochen Rainer Fischer
  • Patent number: 6103143
    Abstract: In the steam reforming of hydrocarbon, particularly methane, under elevated temperature and pressure to produce hydrogen, a feed of steam and hydrocarbon is fed into a first reaction volume containing essentially only reforming catalyst to partially reform the feed. The balance of the feed and the reaction products of carbon dioxide and hydrogen are then fed into a second reaction volume containing a mixture of catalyst and adsorbent which removes the carbon dioxide from the reaction zone as it is formed. The process is conducted in a cycle which includes these reactions followed by countercurrent depressurization and purge of the adsorbent to regenerate it and repressurization of the reaction volumes preparatory to repeating the reaction-sorption phase of the cycle.
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: August 15, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, Jeffrey Raymond Hufton, Shankar Nataraj
  • Patent number: 6004374
    Abstract: A carbonaceous adsorbent membrane is prepared by contacting a hydrophobic carbonaceous adsorbent membrane with an aqueous solution of one or more oxidizing acids and one or more metals selected from the group consisting of copper (+2), chromium (+3), and nickel (+2). The treated membrane is rinsed and dried to yield a hydrophilic carbonaceous adsorbent membrane which is useful for removing water from water-containing gas mixtures.
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: December 21, 1999
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Madhukar Bhaskara Rao, Shivaji Sircar, Timothy Christopher Golden
  • Patent number: 5882380
    Abstract: A single-bed PSA system comprising a blower, an adsorber vessel, and a gas product storage tank separates a gas mixture using a three-step cycle comprising adsorption, evacuation, and pressurization. Pressurization is accomplished by introducing gas from the gas product storage tank into both the feed end and the product end of the adsorber vessel. Preferably a portion of the pressurization gas is introduced into the adsorber vessel by the blower, which also is used for providing feed to the adsorber and for withdrawing gas from the adsorber during the evacuation step.
    Type: Grant
    Filed: October 13, 1997
    Date of Patent: March 16, 1999
    Assignee: Air Products and Chemicals, Inc.
    Inventor: Shivaji Sircar
  • Patent number: 5779768
    Abstract: A condensable component present at low concentration in a feed gas mixture containing the condensable component and a noncondensable component is recovered by selective adsorption from the feed gas mixture in an adsorption step, the resulting adsorbed condensable component is desorbed by a heated purge gas in a regeneration step to yield a purge gas effluent enriched in desorbed condensable component, and the purge gas effluent is cooled to condense and recover the condensable component as a liquid.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: July 14, 1998
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Madhu Anand, Shivaji Sircar, Augustine Ivanhoe Dalton
  • Patent number: 5753010
    Abstract: A method for increasing product recovery or reducing the size of steam methane reformer and pressure swing adsorption systems utilized for hydrogen production. A significant portion of the hydrogen in the PSA depressurization and purge effluent gas, which is otherwise burned as fuel in the reformer, is recovered and recycled to the PSA system to provide additional high purity hydrogen product. This is accomplished by processing selected portions of the depressurization and purge effluent gas in adsorbent membrane separators to increase hydrogen content for recycle to the PSA system. Remaining portions of the depressurization and purge effluent gas which contain lower concentrations of hydrogen are utilized for fuel value in the reformer.
    Type: Grant
    Filed: October 28, 1996
    Date of Patent: May 19, 1998
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, William Emil Waldron, Madhu Anand, Madhukar Bhaskara Rao
  • Patent number: 5753011
    Abstract: A staged adsorbent membrane system is operated to separate a gas mixture wherein more strongly adsorbed secondary components preferentially adsorb and permeate through the adsorbent membrane in the first stage. Less strongly adsorbed primary components are recovered therefrom in a nonpermeate gas product stream. Preferably two stages are utilized wherein the permeate gas from the first stage is introduced into the second stage and the nonpermeate gas from the second stage is recycled to the first stage as additional feed gas to increase the overall recovery and/or purity of the nonpermeate gas product. The two-stage membrane system is operated such that the ratio of the recovery of the primary component in the first stage to the recovery of the primary component in the second stage is less than about 1.0. The method is particularly useful for the recovery of hydrogen from hydrogen-containing gas mixtures.
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: May 19, 1998
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Shivaji Sircar, David Joseph Parrillo
  • Patent number: 5507856
    Abstract: A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is utilized to separate hydrogen-hydrocarbon mixtures and a sweep gas comprising some of the same hydrocarbons is passed across the low pressure side of the membrane to enhance hydrocarbon permeability. Methane is an effective sweep gas which promotes the permeation of heavier hydrocarbons even when methane is present in the membrane feed.
    Type: Grant
    Filed: September 8, 1994
    Date of Patent: April 16, 1996
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Madhukar B. Rao, Shivaji Sircar
  • Patent number: 5507860
    Abstract: Improved composite semipermeable membranes including microporous carbonaceous adsorptive material supported by a porous substrate for use in separating multicomponent gas mixtures in which certain components in the mixture adsorb within the pores of the adsorptive material and diffuse by surface flow through the membrane to yield a permeate stream enriched in these components. Methods for making the improved composite membranes are described including one or more oxidation steps which increase the membrane permeability and selectivity.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: April 16, 1996
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Madhukar B. Rao, Shivaji Sircar, Timothy C. Golden