EP0439126B2 - Système cryogénique de séparation d'air avec colonne d'argon hybride - Google Patents

Système cryogénique de séparation d'air avec colonne d'argon hybride Download PDF

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Publication number
EP0439126B2
EP0439126B2 EP91100775A EP91100775A EP0439126B2 EP 0439126 B2 EP0439126 B2 EP 0439126B2 EP 91100775 A EP91100775 A EP 91100775A EP 91100775 A EP91100775 A EP 91100775A EP 0439126 B2 EP0439126 B2 EP 0439126B2
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Prior art keywords
column
argon
vapor
packing
liquid
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German (de)
English (en)
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EP0439126A1 (fr
EP0439126B1 (fr
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Richard Amory Victor
Michael James Lockett
James Robert Dray
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Praxair Technology Inc
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Praxair Technology Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04666—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system
    • F25J3/04672—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system having a top condenser
    • F25J3/04678—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system having a top condenser cooled by oxygen enriched liquid from high pressure column bottoms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
    • F25J3/04896—Details of columns, e.g. internals, inlet/outlet devices
    • F25J3/04915—Combinations of different material exchange elements, e.g. within different columns
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
    • F25J3/04896—Details of columns, e.g. internals, inlet/outlet devices
    • F25J3/04915—Combinations of different material exchange elements, e.g. within different columns
    • F25J3/04921—Combinations of different material exchange elements, e.g. within different columns within the same column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/10—Mathematical formulae, modeling, plot or curves; Design methods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/12—Particular process parameters like pressure, temperature, ratios

Definitions

  • This invention relates generally to cryogenic rectification wherein a feed comprising oxygen, nitrogen and argon is separated into oxygen-richer, nitrogen-richer, and argon-richer components.
  • An often used commercial system for the separation of a mixture comprising oxygen, nitrogen and argon, e.g. air, is cryogenic rectification.
  • the separation is driven by elevated feed pressure which is generally attained by compressing feed in a compressor prior to introduction into a column system.
  • the separation is carried out by passing liquid and vapor in countercurrent contact through the column or columns on vapor liquid contacting elements whereby more volatile component(s) are passed from the liquid to the vapor, and less volatile component(s) are passed from the vapor to the liquid.
  • cryogenic separation is carried out in a main column system comprising at least one column wherein the feed is separated into nitrogen-rich and oxygen-rich components, and in an auxiliary argon column wherein feed from the main column system is separated into argon-richer and oxygen-richer components.
  • the power to operate the feed compressor and thus drive the separation is the major operating cost of the separation.
  • Pressure drop within the system burdens the feed compression causing increased feed pressure requirements. It is desirable to operate the cryogenic rectification with as low a pressure drop as possible thus reducing feed compression requirements.
  • the lower the pressure level within the columns the greater is the relative volatility between the components. The greater is the relative volatility between the components within a column, the easier is the separation, which in turn increases the recovery of argon, oxygen and nitrogen products.
  • a vapor stream having a relatively high argon concentration is taken from the main column system and passed into and up the argon column while becoming progressively richer in argon.
  • a crude argon product is recovered from the top of the argon column.
  • Vapor flows up the argon column due to a pressure gradient between the argon column feed and the crude argon product.
  • the pressure of the argon column feed is determined by the main column conditions at the vapor takeoff point. Operation of the argon column at a lower pressure is subject to two constraints on how low the pressure can be irrespective of how the lower pressure is achieved.
  • One constraint is that subatmospheric pressure at the top of the argon column should be avoided in order to avoid air leaks into the system.
  • the other constraint involves the temperature difference for the top condenser of the argon column.
  • a low pressure at the top of the argon column also results in a low temperature and thus the temperature difference between the condensing argon and the boiling kettle liquid in the argon condenser is reduced.
  • Aminimum temperature difference of about 0.7°K is necessary for effective operation of the condenser.
  • EP-A-0 328 112 contains a general remark about usage of either trays or packing or a combination of both as vapour-liquid contacting elements in the argon column in order to reduce overall feed compression requirements. No hint is given how to arrange trays and packings within the argon column to gain further benefit from such combination.
  • It is another object of this invention to provide a cryogenic separation apparatus comprising a main column system and an auxiliary argon column, which can operate at a lower average pressure without the need to increase the pressure of liquid passed from the argon column to the main column.
  • Another aspect of this invention is an apparatus for cryogenic separation according to claim 11.
  • distillation means a distillation or fractionation column or zone, i.e., a contacting column or zone wherein liquid and vapor phases are countercurrently contacted to effect separation of a fluid mixture, as for example, by contacting of the vapor and liquid phases on a series of vertically spaced trays or plates mounted within the column or alternatively, on packing elements with which the column if filled.
  • a distillation or fractionation column or zone i.e., a contacting column or zone wherein liquid and vapor phases are countercurrently contacted to effect separation of a fluid mixture, as for example, by contacting of the vapor and liquid phases on a series of vertically spaced trays or plates mounted within the column or alternatively, on packing elements with which the column if filled.
  • double column is used herein to mean a higher pressure column having its upper end in heat exchange relation with the lower end of a lower pressure column.
  • argon column means a column wherein upflowing vapor becomes progressively enriched in argon by countercurrent flow against descending liquid and an argon product is withdrawn from the column.
  • indirect heat exchange means the bringing of two fluid streams into heat exchange relation without any physical contact or intermixing of the fluids with each other.
  • vapor-liquid contacting elements means any devices used as column internals to facilitate mass transfer, or component separation, at the liquid vapor interface during countercurrent flow of the two phases.
  • the term "tray” means a substantially flat plate with openings and liquid inlet and outlet so that liquid can flow across the plate as vapor rises through the openings to allow mass transfer between the two phases.
  • packing means any solid or hollow body of predetermined configuration, size, and shape used as column internals to provide surface area for the liquid to allow mass transfer at the liquid-vapor interface during countercurrent flow of the two phases.
  • random packing means packing wherein individual members do not have any particular orientation relative to each other or to the column axis.
  • structured packing means packing wherein individual members have specific orientation relative to each other and to the column axis.
  • the term "theoretical stage” means the ideal contact between upwardly flowing vapor and downwardly flowing liquid into a stage so that the exiting flows are in equilibrium.
  • Figure 1 is a simplified schematic flow diagram, partly in cross-section, of one preferred embodiment of the apparatus and process of this invention wherein the main column system comprises a double column.
  • Figure 2 is a graphical representation of generalized argon column pressure profiles with argon column height.
  • feed 1 such as air, comprising oxygen, nitrogen and argon is deaned of dust and other particulate matter by passage through filter 2.
  • Filtered feed air 3 is compressed by passage through compressor 4 to a pressure generally within the range of from 4.9 to 13.4 bar (70 to 190 psia).
  • Compressed feed air 5 is then cleaned of high boiling impurities such as water, carbon dioxide and hydrocarbons, by passage through purifier 6.
  • Cleaned, compressed feed air 7 is cooled to near liquefaction temperature by indirect heat exchange in heat exchanger 8 with product and waste streams from the columns.
  • Cleaned, compressed and cooled feed air 9 is then introduced into first column 10 which is the higher pressure column of a double column main column system.
  • main column systems which may be used with this invention include a single column, and two or more columns in series.
  • Column 10 generally is operating at a pressure within the range of from 4.3 to 12.8 bar (60 to 180 pounds per square inch absolute (psia)).
  • a minor fraction 40 of the feed air is withdrawn from the middle of heat exchanger 8, expanded in turbine 41 and introduced into lower pressure column 13 at a point below the nitrogen withdrawal points but above the argon column feed withdrawal point. These withdrawal points will be more fully described below.
  • Column 13 is the lower pressure column of the double column main column system.
  • Nitrogen-enriched vapor 11 is passed through conduit means from column 10 to main condenser 12, which is preferably within second column 13. Main condenser 12 may also be physically located outside the walls of column 13. Within main condenser 12 nitrogen-enriched vapor 11 is condensed by indirect heat exchange with reboiling column 13 bottom liquid. Resulting nitrogen-enriched liquid 14 is passed through conduit means to column 10 as reflux. A portion 15 of the resulting nitrogen-enriched liquid, generally within the range of from 20 to 50 percent, is passed into column 13 at or near the top of the column.
  • Oxygen-enriched liquid 16 is removed from first column 10 and passed into argon column top condenser 17 wherein it is partially vaporized by indirect heat exchange with argon column top vapor. Resulting vapor and liquid are passed into column 13 as streams 18 and 42 respectively at points below the nitrogen withdrawal points but above the argon column feed withdrawal point.
  • Second column 13 operates at a pressure less than that of first column 10 and generally within the range of from 0.9 to 3.2 bar (12 to 45 psia).
  • the fluids introduced into the column are separated by rectification into nitrogen-rich and oxygen-rich components which may be recovered respectively as nitrogen and oxygen products.
  • Oxygen product may be recovered as gas and/or liquid having a purity generally exceeding about 99 percent.
  • Gaseous oxygen product is removed from second column 13 at a point above main condenser 12, passed as stream 19 through heat exchanger 8, and recovered as stream 20.
  • Liquid oxygen product is removed from second column 13 at or below main condenser 12 and recovered as stream 21.
  • Nitrogen product having a purity generally exceeding about 99.9 percent, is removed from the top of second column 13 as stream 22, passed through heat exchanger 8 and recovered as stream 24.
  • Waste nitrogen stream 25 which facilitates operation of the separation system, is also removed from second column 13, passed through heat exchanger 8 and vented as stream 23.
  • Stream 25 is taken from second column 13 at a point below the point where nitrogen-enriched stream 15 is introduced into the column.
  • Figure 1 illustrates one preferred arrangement wherein the vapor-liquid contacting elements within column 10 are all trays 44 and the vapor-liquid contacting elements within column 13 are all packing 43.
  • the vapor-liquid contacting elements within column 10 may also be all packing or may comprise a combination of trays and packing.
  • the vapor-liquid contacting elements within column 13 may also comprise all trays or may comprise a combination of trays and packing.
  • One such combined arrangement for column 13 comprises trays in the portion of the column between the stream 40 introduction point and the stream 25 withdrawal point with the remainder of the vapor-liquid contacting elements being packing.
  • the packing may be either random or structured packing. However, structured packing is preferred over random packing. Examples of structured packing indude Stedman packing, described in U.S. Patent No.
  • the separation system of this invention further comprises the production of crude argon.
  • a stream 26 is withdrawn from an intermediate point of column 13 where the argon concentration is at or dose to a maximum within this column, generally about 10 to 20 percent.
  • Stream 26 is generally and preferably a vapor stream as illustrated in Figure 1. Most of the remainder of stream 26 comprises oxygen while nitrogen may be present in stream 26 in a concentration of less than one percent.
  • Stream 26 is passed from the main column system through conduit means into the lower portion of argon column 27 which is operating at a pressure generally within the range of from 0.9 to 3.2 bar (12 to 45 psia). Vapor flows up column 27 and becomes progressively enriched in argon by countercurrent flow against descending liquid.
  • Argon-enriched vapor 28 is passed from argon column 27 to top condenser 17 wherein it is partially condensed by indirect heat exchange with partially vaporizing oxygen-enriched liquid 16. Resulting partially condensed argon-enriched fluid 29 is passed to separator 30.
  • Argon-enriched vapor 31 is recovered from separator 30 as crude argon product having an argon concentration generally exceeding 96 percent while liquid 32 is passed from separator 30 into argon column 27 as the descending liquid.
  • Liquid accumulating at the bottom of argon column 27, having an oxygen concentration exceeding that of stream 26, is passed as stream 33 into second column 13.
  • the flow of vapor through argon column 27 is effected by a pressure difference between the pressure of stream 26 and the pressure of stream 28.
  • the vapor-liquid contacting elements within argon column 27 comprise at least one tray 45 in the lower portion of the argon column.
  • the lower portion of the argon column is the lower 10 percent of the height of the argon column wherein during operation the argon concentration in the contacting vapor and liquid is generally about 25 percent or less.
  • the vapor-liquid contacting elements are all trays in this lower portion of the argon column.
  • the vapor-liquid contacting elements in the remainder of the argon column where the argon concentration generally exceeds the above-recited concentration are all packing 46.
  • the packing is structured packing.
  • the number of trays in the lower portion of the argon column can range from a minimum of about 1 to 5 trays to a maximum of about 20 to 30 trays.
  • the number of trays depends on the tray pressure drop per theoretical stage, the packing pressure drop per theoretical stage, the number of theoretical stages specified between the top of the upper column and the point from which vapor is taken to feed the argon column, and also on the number of theoretical stages specified in the argon column.
  • the number of trays used must not be so large that the pressure at the top of the argon column falls below atmospheric since there is then a risk of argon product contamination from leaks.
  • the fluid passed from the main column system into the argon column be passed into the lower portion of the argon column where the vapor-liquid contacting elements are trays and preferably, as illustrated in Figure 1, the argon column feed stream is introduced into the argon column at the bottom of the column.
  • the upward flowing vapor within the argon column undergoes a pressure drop while passing through the trayed section thus establishing a significant pressure gradient at the bottom of the column.
  • the use of packing in the upper section of the argon column reduces the pressure gradient over the remainder of the column.
  • the pressure at the bottom of the argon column is not different from that of the incoming stream from the main column system, other than for minor pressure drop in the conduit, and thus liquid from the argon column, such as stream 33 illustrated in Figure 1, may be returned to the main column system without need for pressurization, such as by pumping or liquid head.
  • trays Any suitable type of trays may be used with this invention. Among such types one can name sieve trays, bubble cap trays and valve trays. Trays which produce a higher pressure drop per tray are preferred as in this way the advantages of this invention are attained with fewer trays within the argon column.
  • suitable trays may include sieve trays with low perforation areas.
  • Figure 2 illustrates the pressure profiles of a conventional argon column, an argon column with feed pressure reduction such as by a valve, and the hybrid argon column of this invention.
  • line A-B illustrates the pressure profile of a conventional all packing argon column over the height of the argon column.
  • Line C-D-E illustrates the pressure profile of a conventional all packing argon column wherein the feed is reduced in pressure prior to introduction into the column.
  • Line A-D-E illustrates the pressure profile of the hybrid argon column of this invention over the height of the argon column.
  • the pressure at the top of the hybrid argon column is the same as that of the reduced feed pressure column.
  • the pressure at the bottom of the hybrid argon column exceeds that of the reduced feed pressure column. Accordingly most of the lower pressure advantages are achieved with the hybrid argon column while also enabling fluid return from the argon column to the main column system without need for pressurization of this return stream.
  • the lower pressure column vapor-liquid contacting elements may consist essentially of packing thus reducing the pressure drop over this column and reducing feed compression requirements. Furthermore packing is employed in the argon column to enhance argon recovery.
  • the requisite pressure gradient is provided within the argon column to enable suitable vapor upflow without causing subatmospheric conditions at the top of the argon column, and while maintaining sufficient pressure at the bottom of the argon column to return liquid from the argon column back to the main column system without need for further pressurization.
  • the trays within the lower portion of the argon column simultaneously perform two functions. They serve as means to create a pressure reduction at the inlet of the argon column so that the argon column can operate at lower average pressure levels. Simultaneously they serve as vapor-liquid contacting elements to effect mass transfer between the upflowing vapor and the descending liquid within the argon column.

Claims (18)

  1. Procédé de rectification cryogénique consistant :
    (A) à introduire une charge comprenant de l'oxygène, de l'azote et de l'argon dans un système principal de colonnes (10, 13) comprenant au moins une colonne de rectification ;
    (B) à séparer la charge par contact vapeur-liquide à contre-courant à l'intérieur du système principal de colonnes, en constituants riche en azote et riche en oxygène ;
    (C) à introduire un fluide (26), comprenant de l'argon et de l'oxygène provenant du système principal de colonnes, dans la partie inférieure d'une colonne (27) à argon ; et
    (D) à séparer le fluide, par contact vapeur-liquide à contre-courant à l'intérieur de la colonne à argon sur des éléments de mise en contact vapeur-liquide comprenant à la fois des plateaux (45) et un garnissage (46), en constituants enrichi en argon et enrichi en oxygène ;
    caractérisé par l'utilisation, pour l'étape (D), d'une colonne à argon (27) qui, dans sa portion inférieure, contient en totalité des plateaux (45) et, dans sa partie restante, contient en totalité un garnissage (46), ladite portion inférieure étant la partie inférieure de la colonne à argon dans laquelle, pendant le fonctionnement, la concentration d'argon de la vapeur et du liquide mis en contact est de 25 % ou moins.
  2. Procédé selon la revendication 1, dans lequel le garnissage comprend un garnissage structuré (46).
  3. Procédé selon l'une quelconque des revendications précédentes, dans lequel on fait passer un constituant (33), plus riche en oxygène, de la colonne à argon (27) au système principal de colonnes (10, 13).
  4. Procédé selon l'une quelconque des revendications précédentes, dans lequel on récupère un constituant enrichi en argon ayant une concentration d'argon d'au moins 96 %.
  5. Procédé selon l'une quelconque des revendications précédentes, dans lequel le système principal de colonnes (10, 13) est une colonne double ayant une colonne (13) à pression inférieure en relation d'échange de chaleur avec une colonne (10) à pression supérieure.
  6. Procédé selon la revendication 5 dans lequel la colonne (13) à pression inférieure comporte des éléments de mise en contact vapeur-liquide qui sont en totalité un garnissage (43).
  7. Procédé selon la revendication 6, dans lequel le garnissage (43) dans la colonne (13) à pression inférieure comprend un garnissage structuré.
  8. Procédé selon la revendication 5 dans lequel la colonne (10) à pression supérieure comporte des éléments de mise en contact vapeur-liquide qui sont en totalité des plateaux (44).
  9. Procédé selon l'une quelconque des revendications précédentes, consistant en outre à récupérer un constituant (22) riche en azote en tant qu'azote produit.
  10. Procédé selon l'une quelconque des revendications précédentes, consistant en outre à récupérer un constituant (19, 21) riche en oxygène en tant qu'oxygène produit.
  11. Appareil de rectification cryogénique, comportant
    (A) un système principal de colonnes (10, 13) comprenant au moins une colonne de rectification ayant des éléments (43, 44) de mise en contact vapeur-liquide ;
    (B) une colonne (27) à argon ayant des éléments de mise en contact vapeur-liquide comprenant des plateaux (45) et un garnissage (46) ; et
    (C) des moyens destinés à faire passer un fluide (26) du système principal de colonnes (10, 13) dans la portion inférieure de la colonne (27) à argon,
    caractérisé en ce que la colonne (27) à argon, dans sa portion inférieure, contient en totalité des plateaux (45) et, dans sa partie restante, contient en totalité un garnissage (46), ladite portion inférieure étant la partie inférieure de la colonne à argon dans laquelle, pendant le fonctionnement, la concentration d'argon de la vapeur et du liquide mis en contact est de 25 % ou moins.
  12. Appareil selon la revendication 11, dans lequel la portion inférieure de la colonne (27) à argon forme les 10 % inférieurs de la hauteur de la colonne à argon.
  13. Appareil selon l'une des revendications 11 et 12 dans lequel le garnissage (46) comprend un garnissage structuré.
  14. Appareil selon l'une quelconque des revendications 11 à 13, comportant en outre des moyens destinés à faire passer un fluide (33) de la colonne à argon (27) au système principal de colonnes (10, 13).
  15. Appareil selon l'une quelconque des revendications 11 à 14, dans lequel le système principal de colonnes (10, 13) est une colonne double ayant une colonne (13) à pression inférieure en relation d'échange de chaleur avec une colonne (10) à pression plus élevée.
  16. Appareil selon la revendication 15, dans lequel la colonne (13) à pression inférieure comporte des éléments de mise en contact vapeur-liquide qui sont en totalité un garnissage (43).
  17. Appareil selon la revendication 16, dans lequel le garnissage (43) dans la colonne (13) à pression inférieure comprend un garnissage structuré.
  18. Appareil selon la revendication 15, dans lequel la colonne (10) à pression supérieure comporte des éléments de mise en contact vapeur-liquide qui sont en totalité des plateaux (44).
EP91100775A 1990-01-23 1991-01-22 Système cryogénique de séparation d'air avec colonne d'argon hybride Expired - Lifetime EP0439126B2 (fr)

Applications Claiming Priority (2)

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US46887590A 1990-01-23 1990-01-23
US468875 1990-01-23

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EP0439126A1 EP0439126A1 (fr) 1991-07-31
EP0439126B1 EP0439126B1 (fr) 1993-10-27
EP0439126B2 true EP0439126B2 (fr) 1997-03-05

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EP (1) EP0439126B2 (fr)
JP (1) JPH076736B2 (fr)
KR (1) KR960003274B1 (fr)
BR (1) BR9100289A (fr)
CA (1) CA2034740C (fr)
DE (1) DE69100539T3 (fr)
ES (1) ES2045960T5 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5133790A (en) * 1991-06-24 1992-07-28 Union Carbide Industrial Gases Technology Corporation Cryogenic rectification method for producing refined argon
FR2807150B1 (fr) * 2000-04-04 2002-10-18 Air Liquide Procede et appareil de production d'un fluide enrichi en oxygene par distillation cryogenique
JP2022077733A (ja) * 2020-11-12 2022-05-24 大陽日酸株式会社 安定同位体濃縮装置

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AR243396A1 (es) * 1985-01-18 1993-08-31 Glitsch Mejoras en columnas de fraccionamiento para la separacion de dos o mas componentes liquidos que tienen diferentes volatilidades relativas.
US4871382A (en) * 1987-12-14 1989-10-03 Air Products And Chemicals, Inc. Air separation process using packed columns for oxygen and argon recovery
US4836836A (en) * 1987-12-14 1989-06-06 Air Products And Chemicals, Inc. Separating argon/oxygen mixtures using a structured packing
US4838913A (en) * 1988-02-10 1989-06-13 Union Carbide Corporation Double column air separation process with hybrid upper column
US4842625A (en) * 1988-04-29 1989-06-27 Air Products And Chemicals, Inc. Control method to maximize argon recovery from cryogenic air separation units

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JPH04214174A (ja) 1992-08-05
EP0439126A1 (fr) 1991-07-31
KR960003274B1 (ko) 1996-03-07
EP0439126B1 (fr) 1993-10-27
DE69100539T3 (de) 1997-07-10
ES2045960T5 (es) 1997-05-01
CA2034740C (fr) 1995-03-21
ES2045960T3 (es) 1994-01-16
BR9100289A (pt) 1991-10-22
DE69100539T2 (de) 1994-02-17
JPH076736B2 (ja) 1995-01-30
KR910014141A (ko) 1991-08-31
DE69100539D1 (de) 1993-12-02

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