Triple Column Patents (Class 62/900)
  • Patent number: 6651460
    Abstract: Oxygen-containing gas comprising no more than about 50 mol % oxygen is fed (150) to an auxiliary separation column (40) in a multiple column cryogenic air distillation system comprising at least a higher pressure (“HP”) column (10) and a lower pressure (“LP”) column (30) for separation into nitrogen-rich overhead vapor and oxygen-rich liquid. Oxygen-rich liquid is fed (154) from the auxiliary column (40) to an intermediate location in the LP column (30). The auxiliary column (40) is refluxed with a liquid stream from or derived from the HP column (10). One advantage of the invention is that the diameter of the upper sections (II, III) of the LP column (30) need no longer be larger than the diameter of the rest of the column system thereby increasing the capacity of the column system (under the constraint of a defined maximum column section diameter).
    Type: Grant
    Filed: October 29, 2002
    Date of Patent: November 25, 2003
    Assignee: Air Products and Chemicals, Inc.
    Inventor: Declan P. O'Connor
  • Patent number: 6622520
    Abstract: A cryogenic rectification system for producing low purity oxygen from an auxiliary column to a double column system and which can also effectively produce nitrogen gas product and/or one or more liquid products wherein the lower pressure column of the double column system is reboiled in part by turboexpanded shelf vapor which is condensed in an intermediate reboiler and preferably subcooled prior to passage into the lower pressure column.
    Type: Grant
    Filed: December 11, 2002
    Date of Patent: September 23, 2003
    Assignee: Praxair Technology, Inc.
    Inventors: Neil Mark Prosser, Minish Mahendra Shah
  • Patent number: 6564581
    Abstract: The process and the apparatus are used to obtain argon using a three-column system for the fractionation of air, which has a high-pressure column (11), a low-pressure column (13) and a medium-pressure column (12). A first charge air stream (10, 64) is introduced into the high-pressure column (11), where it is separated into a first oxygen-enriched liquid and a first nitrogen top gas. A first oxygen-enriched fraction (23, 24, 26) from the high-pressure column (11) is introduced into the medium-pressure column (12), where it is separated into a second oxygen-enriched liquid and a second nitrogen top gas. A second oxygen-enriched fraction (33, 35), from the high-pressure column and/or from the medium-pressure column (12), is introduced into the low-pressure column (13), where it is separated into a third oxygen-enriched liquid and a third nitrogen top gas.
    Type: Grant
    Filed: March 21, 2002
    Date of Patent: May 20, 2003
    Assignee: Linde Aktiengesellschaft
    Inventor: Gerhard Pompl
  • Patent number: 6536234
    Abstract: A three column cryogenic rectification system for producing at least one of oxygen and nitrogen employing a medium pressure column which is operating at a pressure between the operating pressures of the higher and lower pressure columns, and which receives an air feed which is at a lower pressure than the air feed to the higher pressure column. The medium pressure column processes oxygen-enriched liquid from the higher pressure column and is reboiled by a fluid taken from below the top of the higher pressure column.
    Type: Grant
    Filed: February 5, 2002
    Date of Patent: March 25, 2003
    Assignee: Praxair Technology, Inc.
    Inventor: Minish Mahendra Shah
  • Patent number: 6272883
    Abstract: A plant for separation of a gas mixture comprises at least two columns which are of the same length. The tops of two of the columns are at the same height.
    Type: Grant
    Filed: January 12, 2001
    Date of Patent: August 14, 2001
    Assignee: L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
    Inventors: Olivier Bruder, Bernard Darredeau, Jean-Yves Lehman
  • Patent number: 6257019
    Abstract: Nitrogen is produced by separation of it from air. Nitrogen so separated is condensed. Most or all of the nitrogen is separated by rectification. At least some of the condensed nitrogen is employed as reflux in the rectification. The nitrogen is both separated and condensed at three or more different pressures.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: July 10, 2001
    Assignee: The BOC Group plc
    Inventors: John Douglas Oakey, Paul Higginbotham
  • Patent number: 6196024
    Abstract: Process for separating air by cryogenic distillation and apparatus including a high pressure column, an intermediate pressure column, a low pressure column having a bottom reboiler and an argon column having a top condenser, a conduit for sending air to the high pressure column, a conduit for sending at least part of a first oxygen enriched liquid from the high pressure column to the intermediate pressure column, a conduit for sending a second oxygen enriched fluid from the bottom of the intermediate pressure column to the low pressure column, a conduit for sending a second nitrogen enriched fluid from the top of the intermediate pressure column to the low pressure column or to a top condenser of the argon column, a conduit for sending a heating gas to the bottom reboiler of the low pressure column, a conduit for removing a third oxygen enriched fluid from the low pressure column, a conduit for sending a nitrogen enriched liquid from the high pressure column to the low pressure column, a conduit for sending a
    Type: Grant
    Filed: May 25, 1999
    Date of Patent: March 6, 2001
    Assignee: L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
    Inventor: Bao Ha
  • Patent number: 6185960
    Abstract: In a process for the production of a pressurized gaseous product by low-temperature separation of air, which is at times done in a gas operation and at times in a combined operation, whereby in the gas operation and in the combined operation (a) purified charging air is cooled under pressure, partially liquefied, and subjected to rectification to produce gaseous and liquid fractions, (b) extremely cold liquid of at least one of the liquid fractions from the rectification is evaporated under elevated pressure by indirect heat exchange with feed air, heated, and obtained as a pressurized gaseous product, whereby in combined operation, (c) the cold that is required for this purpose is generated in an air-refrigeration cycle, by air being compressed in the refrigeration cycle and work expanded, in which case heat is removed from the air, and the actively depressurized air that is partially in countercurrent is heated again with the charging air that is to be cooled and then repressurized, (d) extremely cold liqui
    Type: Grant
    Filed: April 8, 1999
    Date of Patent: February 13, 2001
    Assignee: Linde Aktiengesellschaft
    Inventor: Jürgen Voit
  • Patent number: 6182470
    Abstract: In this air distillation plant (1) comprising a double column and a mixing column (5), the medium-pressure column (2), the low-pressure column (3) and the mixing column (5) are placed one on top of another, forming a single erected structure. Application to the supply of impure oxygen for the iron and steel industry.
    Type: Grant
    Filed: April 30, 1999
    Date of Patent: February 6, 2001
    Assignee: L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
    Inventor: Alain Guillard
  • Patent number: 5934104
    Abstract: The present invention is an improvement to a nitrogen generator enabling the process to efficiently coproduce oxygen with low recovery, typically less than 70% and preferably less than 55%, in addition to the primary product, nitrogen. In the nitrogen generator process, air is distilled in a distillation column system having a higher pressure column and a lower pressure column. The feed air is compressed, treated to remove water and carbon dioxide, cooled to near its dew point and fed to the higher pressure column of the distillation column system. The nitrogen product is produced by removing an overhead vapor stream from at least one of the columns of the distillation column system. At least one oxygen-enriched stream is removed from the lower pressure column.
    Type: Grant
    Filed: June 2, 1998
    Date of Patent: August 10, 1999
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Zbigniew Tadeusz Fidkowski, Donn Michael Herron, Jeffrey Alan Hopkins
  • Patent number: 5921107
    Abstract: A method for producing a small amount of oxygen, related to a nitrogen generator unit, is provided. In a nitrogen rectification column which cools down and liquefies feed air after moisture and carbon dioxide contained therein are removed, thereby producing nitrogen, oxygen-rich liquid air is used as a cold source for a nitrogen condenser and the thus-obtained oxygen-rich air is then used as a heating source for a reboiler in an oxygen rectification column.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: July 13, 1999
    Assignee: Teisan Kabushiki Kaisha
    Inventor: Takao Yamamoto
  • Patent number: 5881570
    Abstract: A cryogenic rectification plant comprising a double column and a side column having a bottom reboiler wherein feed air is passed into the double column by way of the bottom reboiler and an auxiliary compressor is connected in parallel with the feed air line.
    Type: Grant
    Filed: April 6, 1998
    Date of Patent: March 16, 1999
    Assignee: Praxair Technology, Inc.
    Inventors: Raymond Francis Drnevich, Ravindra Fulchand Pahade, Minish Mahendra Shah
  • Patent number: 5730004
    Abstract: The process and apparatus are based on a triple-column system, having at least a high-pressure column (7), a medium-pressure column (8) and a low-pressure column (9). Feed air (1) is compressed to a first pressure (2). A first partial stream (101, 103, 104) of the resultant air feed (3) is sent into high-pressure column (7) after it has been compressed to a second pressure (5, 102), which is at least equal to the operating pressure of the high-pressure column (7). A second partial stream (201, 202) of the compressed air feed (3) is fed into the medium-pressure column (8). A third partial stream (301, 303, 304) of the compressed air feed (3) is engine-expanded (305) and then fed (306) into the low-pressure column (9). Fractions (18; 26) from the high-pressure column (7) and the medium-pressure column (8) are introduced at least partially into low-pressure column (19, 20; 28, 29). Nitrogen-enriched top fractions (10; 21) from high-pressure column (7) and medium-pressure column (8) are condensed (11; 22).
    Type: Grant
    Filed: October 10, 1996
    Date of Patent: March 24, 1998
    Assignee: Linde Aktiengesellschaft
    Inventor: Jurgen Voit
  • Patent number: 5715706
    Abstract: Cooled and purified air is introduced into a higher pressure rectification column and separated into oxygen-enriched liquid and nitrogen vapour. A stream of the oxygen-enriched liquid is flashed through a pressure reducing valve to form a mixture of liquid further enriched in oxygen and vapour depleted of oxygen. The liquid is reboiled by reboiler. A stream of the further enriched liquid is reboiled in condenser and is introduced into a lower pressure rectification column for separation into oxygen and nitrogen products. Reflux for the columns and is formed by condensing in condenser nitrogen vapour separated in the higher pressure rectification column. A reboiler provides an upward flow of vapour through the column. The condenser and reboiler take the form of a single heat exchanger. The reboiler is located in a phase separator, the reboiler is located in a rectification column containing liquid-vapour contact devices above the level at which fluid issuing from the valve is introduced.
    Type: Grant
    Filed: August 29, 1996
    Date of Patent: February 10, 1998
    Assignee: The BOC Group plc
    Inventor: Thomas Rathbone
  • Patent number: 5682764
    Abstract: A cryogenic process for producing impure oxygen and/or substantially pure nitrogen utilizes a classic double column arrangement and an additional third column operating at a medium pressure, i.e. between the pressure of the higher pressure stage and the lower pressure stage of the double column system. A portion of the feed air is separated in the stages of the double column system, and another portion of the feed air is distilled in the medium pressure stage. Crude liquid oxygen from the higher pressure stage and/or the medium pressure stage is reduced in pressure and boiled in a reboiler/condenser at the top of the medium pressure column. The vaporized crude liquid oxygen from the top reboiler/condenser of the medium pressure column is subsequently introduced as a vapor feed to the lower pressure stage, which reduces irreversibilities of separation in the lower pressure stage.
    Type: Grant
    Filed: October 25, 1996
    Date of Patent: November 4, 1997
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Rakesh Agrawal, Zbigniew Tadeusz Fidkowski
  • Patent number: 5664438
    Abstract: A cryogenic rectification system for producing low purity oxygen and high purity nitrogen, preferably at elevated pressure, wherein nitrogen-rich vapor from a higher pressure column is turboexpanded and condensed against lower pressure column intermediate liquid prior to being passed into the lower pressure column and low purity oxygen is produced in an auxiliary side column driven by fluid from the higher pressure column.
    Type: Grant
    Filed: August 13, 1996
    Date of Patent: September 9, 1997
    Assignee: Praxair Technology, Inc.
    Inventors: Dante Patrick Bonaquist, Susan Marie Sattan
  • Patent number: 5644933
    Abstract: A stream of compressed air is purified in a unit by removal of carbon dioxide and water vapour. The air is cooled by passage through a heat exchanger to a temperature suitable for its rectification. The air is separated in a higher pressure rectifier into oxygen-enriched liquid and nitrogen vapour. A stream of the oxygen-enriched liquid is reduced in pressure and introduced into a phase separator provided with a reboiler with the result that further separation takes place and a liquid further enriched in oxygen and an intermediate vapour are formed. A stream of the further-enriched liquid is separated into oxygen and nitrogen in a lower pressure rectifier. A stream of the intermediate vapour is condensed in a condenser and is introduced into the lower pressure rectifier.
    Type: Grant
    Filed: January 3, 1996
    Date of Patent: July 8, 1997
    Assignee: The BOC Group plc
    Inventor: Thomas Rathbone
  • Patent number: 5582035
    Abstract: Cooled and purified air is introduced into a higher pressure rectification column and separated into oxygen-enriched liquid and nitrogen vapor. A stream of the oxygen-enriched liquid is flashed through a pressure reducing valve to form a mixture of liquid further enriched in oxygen and vapor depleted of oxygen. The liquid is reboiled by reboiler. A stream of the further enriched liquid is reboiled in condenser and is introduced into a lower pressure rectification column for separation into oxygen and nitrogen products. Reflux for the columns and is formed by condensing in condenser nitrogen vapor separated in the higher pressure rectification column. A reboiler provides an upward flow of vapor through the column. The condenser and reboiler take the form of a single heat exchanger. The reboiler is located in a phase separator, the reboiler is located in a rectification column containing liquid-vapor contact devices above the level at which fluid issuing from the valve is introduced.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: December 10, 1996
    Assignee: The BOC Group plc
    Inventors: Thomas Rathbone, John T. Lavin, David Stuart
  • Patent number: 5582032
    Abstract: A process for producing an ultra-high purity fluid product comprising the steps of collecting in the lower portion of a cryogenic fractionation zone an ultra-high purity fluid product; providing reboil to said fractionation zone by condensing a portion of a lesser purity composition of the same fluid product by indirect heat exchange in a first reboiler; and vaporizing said portion of said lesser purity composition by indirect heat exchange with a warmer stream of an impure fluid.
    Type: Grant
    Filed: August 11, 1995
    Date of Patent: December 10, 1996
    Assignee: Liquid Air Engineering Corporation
    Inventors: James T. Shelton, deceased, Bao Ha