Patents by Inventor Prakash Narayan

Prakash Narayan 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: 10472258
    Abstract: A carrier gas is directed through a humidification chamber in a humidifier, where the carrier gas flow is directly contacted with a feed liquid to humidify the carrier gas with water evaporated from the feed liquid, producing a humidified gas flow. The humidified gas flow is then compressed in a compressor and then directed through a dehumidification chamber in a dehumidifier, where the compressed humidified gas flow is dehumidified to condense water from the compressed humidified gas flow. The dehumidified gas flow is then expanded in an expander, wherein the expansion of the dehumidified gas flow generates motion (e.g., rotation of a shaft), and wherein the motion generated in the expander is transferred to the compressor, where the motion compresses the humidified gas flow. Heat is also removed from the expanded dehumidified gas flow and transferred to compressed dehumidified gas flow upstream from the expander.
    Type: Grant
    Filed: June 29, 2015
    Date of Patent: November 12, 2019
    Assignees: Massachusetts Institute of Technology, King Fahd University of Petroleum and Minerals
    Inventors: Amro Al-Qutub, Prakash Narayan Govindan, John H. Lienhard
  • Patent number: 10463985
    Abstract: Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: November 5, 2019
    Assignee: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Maximus G. St. John, Steven Lam
  • Publication number: 20190329152
    Abstract: Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).
    Type: Application
    Filed: April 12, 2019
    Publication date: October 31, 2019
    Applicant: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Maximus G. St. John, Steven Lam
  • Publication number: 20190300386
    Abstract: Embodiments described generally relate to systems comprising a humidifier (e.g., a bubble column humidifier) and a heating device (e.g. a heat exchanger), and associated methods. In certain embodiments, the heating device heats a first liquid stream comprising a condensable fluid in liquid phase (e.g., water) and a dissolved salt (e.g., NaCl) to a relatively low temperature (e.g., about 90° C. or less) prior to the first liquid stream entering the humidifier through a main humidifier liquid inlet. In some cases, the system comprising the humidifier and the heating device requires only low-grade heat to operate, which may be advantageous due to the low cost and high availability of such heat.
    Type: Application
    Filed: April 8, 2019
    Publication date: October 3, 2019
    Applicant: Gradiant Corporation
    Inventors: Steven Lam, Conor Thomas Wilson, Maximus G. St. John, Prakash Narayan Govindan
  • Publication number: 20190282921
    Abstract: Condensing apparatuses and their use in various heat and mass exchange systems are generally described. The condensing apparatuses, such as bubble column condensers, may employ a heat exchanger positioned external to the condensing vessel to remove heat from a bubble column condenser outlet stream to produce a heat exchanger outlet stream. In certain cases, the condensing apparatus may also include a cooling device positioned external to the vessel configured and positioned to remove heat from the heat exchanger outlet stream to produce a cooling device outlet stream. The condensing apparatus may be configured to include various internal features, such as a vapor distribution region and/or a plurality of liquid flow control weirs and/or chambers within the apparatus having an aspect ratio of at least 1.5. A condensing apparatus may be coupled with a humidifier to form part of a desalination system, in certain cases.
    Type: Application
    Filed: March 20, 2019
    Publication date: September 19, 2019
    Applicant: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Steven Lam, Maximus G. St. John
  • Publication number: 20190282922
    Abstract: A multi-stage bubble-column vapor mixture condenser comprises at least a first stage and a second stage. Each stage includes a carrier-gas inlet and a carrier-gas outlet, as well as a condenser chamber containing a condensing bath in fluid communication with the carrier-gas inlet and the carrier-gas outlet. The carrier-gas inlet is positioned to bubble carrier gas from the carrier-gas inlet up through the condensing bath, overcoming a hydrostatic head of the condensing bath. The carrier-gas outlet is positioned with an opening for carrier-gas extraction above the condensing bath, wherein the first-stage carrier-gas outlet is in fluid communication with the carrier-gas inlet of the second stage to facilitate flow of the carrier gas through the condensing bath in the condenser chamber of the first stage and then through the condensing bath in the condenser chamber of the second stage.
    Type: Application
    Filed: May 7, 2019
    Publication date: September 19, 2019
    Applicants: Massachusetts Institute of Technology, King Fahd University of Petroleum and Minerals
    Inventors: Prakash Narayan Govindan, Gregory P. Thiel, Ronan K. McGovern, John H. Lienhard, Mostafa H. Elsharqawy
  • Publication number: 20190209947
    Abstract: A counter-flow simultaneous heat and mass exchange device is operated by directing flows of two fluids into a heat and mass exchange device at initial mass flow rates where ideal changes in total enthalpy rates of the two fluids are unequal. At least one of the following state variables in the fluids is measured: temperature, pressure and concentration, which together define the thermodynamic state of the two fluid streams at the points of entry to and exit from the device. The flow rates of the fluids at the points of entry and/or exit to/from the device are measured; and the mass flow rate of at least one of the two fluids is changed such that the ideal change in total enthalpy rates of the two fluids through the device are brought closer to being equal.
    Type: Application
    Filed: February 6, 2019
    Publication date: July 11, 2019
    Applicant: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Maximus G. St. John, Karim M. Chehayeb, Steven Lam
  • Patent number: 10345058
    Abstract: Systems and methods for the removal of scale in humidification-dehumidification desalination apparatuses are generally described.
    Type: Grant
    Filed: November 18, 2016
    Date of Patent: July 9, 2019
    Assignee: Gradiant Corporation
    Inventors: Maximus G. St. John, Jonn-Ross Andrews, Prakash Narayan Govindan
  • Patent number: 10322357
    Abstract: Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: June 18, 2019
    Assignee: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Maximus G. St. John, Steven Lam
  • Patent number: 10308537
    Abstract: Systems and methods related to the desalination of aqueous solutions containing one or more dissolved salts are generally described.
    Type: Grant
    Filed: September 23, 2014
    Date of Patent: June 4, 2019
    Assignee: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Steven Lam, Maximus G. St. John, Mark Zaloudek, Anurag Bajpayee
  • Patent number: 10308526
    Abstract: Water treatment systems and associated methods are generally described. Certain embodiments of the water treatment systems and methods described herein may be used to treat water comprising one or more contaminants (e.g., oil, grease, suspended solids, scale-forming ions, volatile organic material) to remove at least a portion of the one or more contaminants. In some embodiments, at least a portion of the treated water may be used directly in certain applications (e.g., oil and/or gas extraction processes). In some embodiments, at least a portion of the treated water may undergo desalination to produce substantially pure water and/or concentrated brine.
    Type: Grant
    Filed: May 21, 2015
    Date of Patent: June 4, 2019
    Assignee: Gradiant Corporation
    Inventors: Maximus G. St. John, Steven Lam, Prakash Narayan Govindan
  • Patent number: 10301198
    Abstract: Disclosed herein are systems and methods in which multivalent ions are selectively retained in an aqueous stream. According to certain embodiments, multiple separations may be used to process an aqueous feed stream containing solubilized monovalent ions and solubilized multivalent ions to produce a stream enriched in the solubilized multivalent ions. The separations may be arranged, according to certain embodiments, to enhance the overall separation process such that the product stream contains—relative to the initial aqueous feed stream—a high amount of solubilized multivalent ions, a high amount of water from the aqueous feed stream, and/or a high ratio of solubilized multivalent ions to solubilized monovalent ions.
    Type: Grant
    Filed: August 12, 2016
    Date of Patent: May 28, 2019
    Assignee: Gradiant Corporation
    Inventors: Maximus G. St. John, Looh Tchuin Choong, Prakash Narayan Govindan
  • Patent number: 10294123
    Abstract: Embodiments described generally relate to systems comprising a humidifier (e.g., a bubble column humidifier) and a heating device (e.g. a heat exchanger), and associated methods. In certain embodiments, the heating device heats a first liquid stream comprising a condensable fluid in liquid phase (e.g., water) and a dissolved salt (e.g., NaCl) to a relatively low temperature (e.g., about 90° C. or less) prior to the first liquid stream entering the humidifier through a main humidifier liquid inlet. In some cases, the system comprising the humidifier and the heating device requires only low-grade heat to operate, which may be advantageous due to the low cost and high availability of such heat.
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: May 21, 2019
    Assignee: Gradiant Corporation
    Inventors: Steven Lam, Conor Thomas Wilson, Maximus G. St. John, Prakash Narayan Govindan
  • Patent number: 10286335
    Abstract: Condensing apparatuses and their use in various heat and mass exchange systems are generally described. The condensing apparatuses, such as bubble column condensers, may employ a heat exchanger positioned external to the condensing vessel to remove heat from a bubble column condenser outlet stream to produce a heat exchanger outlet stream. In certain cases, the condensing apparatus may also include a cooling device positioned external to the vessel configured and positioned to remove heat from the heat exchanger outlet stream to produce a cooling device outlet stream. The condensing apparatus may be configured to include various internal features, such as a vapor distribution region and/or a plurality of liquid flow control weirs and/or chambers within the apparatus having an aspect ratio of at least 1.5. A condensing apparatus may be coupled with a humidifier to form part of a desalination system, in certain cases.
    Type: Grant
    Filed: September 12, 2014
    Date of Patent: May 14, 2019
    Assignee: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Steven Lam, Maximus G. St. John
  • Publication number: 20190106334
    Abstract: Selective scaling in water treatment systems in which desalination is performed is generally described. According to certain embodiments, the location of the formation of solid scale within a water treatment system is controlled by adjusting one or more system parameters, such as the temperature and/or flow velocity of a saline stream within the water treatment system.
    Type: Application
    Filed: August 20, 2018
    Publication date: April 11, 2019
    Applicant: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Steven Lam, Maximus G. St. John, Jonn-Ross Andrews
  • Patent number: 10245555
    Abstract: Disclosed herein are systems and methods in which ion-selective separation and multi-stage osmotic separation is used to produce multivalent-ion-rich process streams. According to certain embodiments, multiple separations may be used to process an aqueous feed stream containing solubilized monovalent ions and solubilized multivalent ions to produce a stream enriched in the multivalent ions. The separations may be arranged, according to certain embodiments, to enhance the overall separation process such that the product stream contains—relative to the initial aqueous feed stream—a high amount of multivalent ions, a high amount of water from the aqueous feed stream, and/or a high ratio of multivalent ions to monovalent ions.
    Type: Grant
    Filed: August 12, 2016
    Date of Patent: April 2, 2019
    Assignee: Gradiant Corporation
    Inventors: Maximus G. St. John, Looh Tchuin Choong, Prakash Narayan Govindan
  • Patent number: 10239765
    Abstract: A counter-flow simultaneous heat and mass exchange device is operated by directing flows of two fluids into a heat and mass exchange device at initial mass flow rates where ideal changes in total enthalpy rates of the two fluids are unequal. At least one of the following state variables in the fluids is measured: temperature, pressure and concentration, which together define the thermodynamic state of the two fluid streams at the points of entry to and exit from the device. The flow rates of the fluids at the points of entry and/or exit to/from the device are measured; and the mass flow rate of at least one of the two fluids is changed such that the ideal change in total enthalpy rates of the two fluids through the device are brought closer to being equal.
    Type: Grant
    Filed: January 9, 2017
    Date of Patent: March 26, 2019
    Assignee: Gradiant Corporation
    Inventors: Prakash Narayan Govindan, Maximus G. St. John, Karim M. Chehayeb, Steven Lam
  • Publication number: 20190084842
    Abstract: Systems and methods related to desalination systems are described herein. According to some embodiments, the desalination systems are hybrid systems comprising one or more first desalination units and one or more second desalination units. In some embodiments, the one or more second desalination units, which may form a fluidic circuit that is located downstream from the one or more first desalination units, may be configured to desalinate higher salinity liquid streams than the one or more first desalination units. In certain embodiments, the one or more first desalination units are operated under steady-state conditions and/or configured to operate under steady-state conditions. In certain embodiments, the one or more second desalination units are transiently operated and/or configured to facilitate transient operation.
    Type: Application
    Filed: February 22, 2017
    Publication date: March 21, 2019
    Applicant: Gradiant Corporation
    Inventors: Maximus G. St. John, Steven Lam, Prakash Narayan Govindan
  • Publication number: 20190031531
    Abstract: Temperature-matching of an injected influent stream with a location along a humidifier feed stream flow path is generally described. According to embodiments, an influent stream can be injected into and combined with a feed stream of a humidifier at a location on the humidifier feed stream flow path at which the temperature of the feed stream most closely matches the temperature of hot influent stream.
    Type: Application
    Filed: July 31, 2017
    Publication date: January 31, 2019
    Applicant: Gradiant Corporation
    Inventors: Steven Lam, Prakash Narayan Govindan
  • Publication number: 20190022550
    Abstract: The present disclosure is related to systems and methods for the formation of solid salts using a humidifier. According to certain embodiments, the flow velocity of a gas in the humidifier can be relatively high during the formation of the solid salt. In some embodiments, the humidifier comprises a multi-stage bubble column humidifier.
    Type: Application
    Filed: January 20, 2017
    Publication date: January 24, 2019
    Applicant: Gradiant Corporation
    Inventors: Steven Lam, Maximus G. St. John, Prakash Narayan Govindan, Conor Thomas Wilson