EP0229803B1 - Process and plant for the distillation of air - Google Patents

Process and plant for the distillation of air Download PDF

Info

Publication number
EP0229803B1
EP0229803B1 EP86904215A EP86904215A EP0229803B1 EP 0229803 B1 EP0229803 B1 EP 0229803B1 EP 86904215 A EP86904215 A EP 86904215A EP 86904215 A EP86904215 A EP 86904215A EP 0229803 B1 EP0229803 B1 EP 0229803B1
Authority
EP
European Patent Office
Prior art keywords
column
section
argon
liquid
low pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP86904215A
Other languages
German (de)
French (fr)
Other versions
EP0229803A1 (en
Inventor
Jean-Renaud Brugerolle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority to AT86904215T priority Critical patent/ATE50857T1/en
Publication of EP0229803A1 publication Critical patent/EP0229803A1/en
Application granted granted Critical
Publication of EP0229803B1 publication Critical patent/EP0229803B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04351—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J3/00—Removing solid residues from passages or chambers beyond the fire, e.g. from flues by soot blowers
    • F23J3/02—Cleaning furnace tubes; Cleaning flues or chimneys
    • 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
    • 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
    • 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
    • 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
    • F25J3/04248—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
    • F25J3/04309—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 nitrogen
    • 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
    • F25J3/04321—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 oxygen
    • 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
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04393—Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
    • 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
    • F25J3/0446—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 the heat generated by mixing two different phases
    • 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
    • F25J3/0466—Producing crude argon in a crude argon column as a parallel working rectification column or auxiliary column system in a single pressure main column system
    • 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
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04709—Producing crude argon in a crude argon column as an auxiliary column system in at least a dual pressure main column system
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/04—Processes or apparatus using separation by rectification in a dual pressure main column system
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/08—Processes or apparatus using separation by rectification in a triple pressure main column system
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/32—Processes or apparatus using separation by rectification using a side column fed by a stream from the 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/34—Processes or apparatus using separation by rectification using a side column fed by a stream from the 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/30—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes
    • 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
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/50—Oxygen or special cases, e.g. isotope-mixtures or low purity O2
    • 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
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/50—Separating low boiling, i.e. more volatile components from oxygen, e.g. N2, Ar
    • 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/42—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being nitrogen
    • 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/50—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being oxygen
    • 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/52—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being oxygen enriched compared to air ("crude oxygen")
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S62/00—Refrigeration
    • Y10S62/923—Inert gas
    • Y10S62/924—Argon

Definitions

  • the present invention relates to the air distillation technique by means of an installation provided with an argon production column.
  • air distillation installations provided with an argon production column generally comprise a double column consisting of a medium pressure distillation column operating at about 6 bars, of a low distillation column pressure operating slightly above atmospheric pressure, and a condenser-vaporizer.
  • the air is sent, after purification and cooling, to the tank of the medium pressure column.
  • the “rich liquid (oxygen-enriched air) collected in the bottom of the medium pressure column is sent to the feed at an intermediate point in the low pressure column, while part of the“ poor liquid ”, consisting almost entirely of nitrogen, collected at the head of the medium pressure column is sent to reflux at the head of the low pressure column.
  • the low-pressure column is connected to the argon production column by a pipe called “argon tapping and a return pipe for liquid less rich in argon.
  • the low pressure column is generally provided in the tank with gaseous oxygen and liquid oxygen withdrawal pipes, and the medium pressure column is generally provided at the head with gaseous nitrogen and liquid nitrogen withdrawal pipes.
  • the vapor at the top of the low pressure column (“impure nitrogen”) consists of nitrogen containing up to a few% of oxygen and is generally discharged into the atmosphere.
  • FR-A-2 550 325 proposes a solution to limit this drawback. This solution has the advantage of being simple, but its effectiveness is limited.
  • distillation of a given air flow is capable of supplying approximately 21% of this oxygen flow and, under certain conditions, this quantity of oxygen is in excess of actual needs, while other productions , including argon, are sought after.
  • the object of the invention is to make it possible in all cases to optimize the excess oxygen in order to increase the desired productions, in particular that of argon.
  • the subject of the invention is a process for the distillation of air by means of an installation comprising a main distillation apparatus associated with an argon production column by an argon tapping pipe, this process being such that defined in claim 1.
  • the invention also relates to an installation intended for the implementation of such a method.
  • This installation is as defined in claim 13.
  • a “column” or “section of a column is a material and heat exchange apparatus having the structure of a distillation column, that is to say comprising a packing or a certain number of trays of the type used in distillation.
  • Figure 1 illustrates by a diagram how a conventional air distillation installation, shown in more detail in the other figures, is modified according to the invention.
  • At least two sections of mixing column K1 and K2 are added to the conventional installation, operating under two pressures P1 and P2 which, as will be seen below, may or may not be equal.
  • the K1 section is supplied at its base with nitrogen gas which can contain up to a few % of oxygen but practically devoid of argon (that is to say containing less than 1% of argon, and preferably less than 0.05% of argon), while the section K2 is supplied at its summit by liquid oxygen practically devoid of argon (with the same meaning as above) and nitrogen.
  • the head vapor of the section K1 is sent to the base of the section K2, and the tank liquid of the latter is sent in reflux to the top of the section K1.
  • lean liquid LP1 consisting of nitrogen containing up to a few% of oxygen, is drawn off and impure oxygen, that is to say containing, is drawn off at the top of the section K2. up to about 15% nitrogen, and preferably about 5-10% nitrogen.
  • At least one intermediate withdrawal is carried out between the base of the section K1 and the top of the section K2, to constitute a residual gas from the installation composed of an oxygen-nitrogen mixture at approximately 10 to 30% d oxygen, and therefore having a composition close to that of air but devoid of argon.
  • the intermediate racking is carried out between the sections K1 and K2. It can be constituted by overhead steam from section K1, which directly supplies the residual gas R.
  • tank liquid LR1 from section K2, this liquid being made up of a mixture oxygen-nitrogen with a content of approximately 40 to 75% of oxygen; this liquid is then sent to the head of a third section of mixing column K3, operating under a pressure P3 and supplied at its base, like the section K1, with nitrogen gas which is possibly impure but practically without argon.
  • the residual gas R1 is then drawn off at the head of the section K3, while the tank liquid of this section constitutes lean liquid LP2 consisting, like the liquid LP1, of nitrogen containing up to a few% of oxygen.
  • the LP1 and LP2 liquids are sent back to the installation to improve the distillation; the impure gaseous oxygen withdrawn at the head of the section K2 can constitute a production gas, or be purified to produce pure gaseous oxygen, as will be seen below.
  • the source of the liquid oxygen and of the nitrogen gas stream (s) will appear in the following description.
  • the diagram in FIG. 1 ensures a remixing of liquid oxygen and nitrogen gas, both almost free of argon, under conditions close to reversibility, which corresponds to recovery of energy.
  • This energy manifests itself in the form of a heat pump type refrigeration transfer between the liquid oxygen and the lean liquid LP1-LP2 and can be used to increase the production of the installation other than oxygen, namely nitrogen gas under pressure, liquid productions and especially argon, as will appear in the following description. It is noted that the above technical effect would also be obtained by supplying the top of the section K2 with liquid oxygen containing up to a few% of nitrogen as an impurity.
  • FIGS 2 to 9 show several examples of implementation of the basic principle illustrated in Figure 1 with double column air distillation plants.
  • the air distillation installation shown in FIG. 2 is intended to produce, on the one hand, impure oxygen containing approximately 5 to 10% nitrogen, on the other hand, argon, and optionally nitrogen. It essentially comprises a double column 1, an argon production column 2, a remixing column 3 and a remixing minaret 4.
  • the double column 1 comprises, in a conventional manner, a lower column 5 operating under a medium pressure MP of the order of 6 bar absolute, an upper column 6 operating under a low pressure BP slightly above atmospheric pressure, and a vaporizer- condenser 7 which puts in heat exchange relation the tank liquid (practically pure liquid oxygen) of the low pressure column with the overhead vapor (practically pure nitrogen) of the medium pressure column.
  • the air to be treated, compressed to 6 bars, purified and cooled near its dew point, is injected at the bottom of the medium pressure column.
  • the tank liquid in this column rich in oxygen (rich liquid LR at about 40% oxygen) contains almost all of the oxygen and argon in the incoming air; it is expanded and injected at 8 at an intermediate location of the low pressure column, while liquid from the top of column 5 (liquid poor in oxygen, LP), is expanded and injected at 9 at the top of the low pressure column.
  • a pipe 10 for argon tapping sends a gas almost free of nitrogen to column 2, and a pipe 11 brings the tank liquid from the latter, slightly less rich in argon, at about near the same level in the low pressure column.
  • the impure argon (argon mixture) is extracted from the top of column 2 and is then purified in a conventional manner.
  • the impure oxygen thus produced contains practically only nitrogen as an impurity.
  • the remixing minaret 4 constitutes the section of mixing column K3 in FIG. 1. Its base communicates directly with the top of the low pressure column 6. It is therefore supplied at its base with impure nitrogen (nitrogen containing up to to a few% of oxygen). At its summit, this minaret is supplied with 13 by the rich liquid LR1 coming from column 3 and suitably expanded.
  • the relatively reversible remixing of the impure nitrogen and the rich liquid LR1 produces an additional quantity of poor liquid LP2, consisting of nitrogen containing up to a few% of oxygen, which falls into column 6 and increases the reflux there.
  • the waste gas R1 devoid of argon and whose composition is close to that of air is evacuated.
  • part of the rich liquid LR or LR1 can be expanded and vaporized in a condenser at the head of column 2, then returned to column 6 near level 8. Furthermore, as shown, part of the vapor from the top of column 6 can be withdrawn, for example to produce by distillation in an auxiliary column section (not shown) pure nitrogen under low pressure.
  • liquid is taken from the low pressure column, a few trays above the argon tapping 10, and sent to the head of an auxiliary low pressure column 14; the latter is supplied at its base with impure oxygen from the mixing column 3, expanded at low pressure in a turbine 15.
  • the bottom liquid of the column 14 is impure oxygen without argon, that the is added upstream of the pump 12 to the pure liquid oxygen withdrawn from the low pressure column. All the argon contained in the liquid injected at the top of the column 14 leaves with the overhead vapor of this column and is returned to the low pressure column 6, at about the same level as the withdrawal of said liquid.
  • the column 3 operates in the vicinity of the low pressure and directly receives at the head liquid oxygen coming from the tank of the column 6.
  • the turbine 15 of FIG. 3 is eliminated and the columns 3 and 14 are combined in a single ferrule 16.
  • the tank of column 3 is supplied with nitrogen obtained by expansion in a turbine 17 of medium pressure nitrogen. As shown, medium pressure nitrogen expanded in the turbine 17 and then in an expansion valve 17A can also be blown at the head of the column 6.
  • FIG. 5 shows another means of supplying low pressure nitrogen at the base of column 3: the upper part of column 6 is split by an auxiliary column 18 operating at a somewhat higher pressure, for example 1.8 bar against 1.4 bar for column 6.
  • Part of the treated air flow is diverted and expanded to 1.8 bar in a turbine 19.
  • Part of the turbinated flow is sent to the base of column 18, which receives at the head, like column 6, lean liquid at the correct pressure.
  • the rest of the turbined air is expanded to 1.4 bar in an expansion valve 20 and blown into column 6, as is the tank liquid in column 18. It is impure nitrogen, containing up to at a few% of oxygen and practically no argon, withdrawn at the head of column 18, which is used to feed the base of column 3.
  • Figure 6 illustrates a variant of Figure 5 which eliminates the pump (not shown) for raising the liquid LP1.
  • the section K1 is transferred above the column 18, in the same shell as the latter, and the liquid LR1 is shared between the top of the minaret 4 and that of the section K1.
  • a second waste gas R is then produced at the head of the section K1, as indicated in phantom in FIG. 6.
  • the residual gas R1 leaves the minaret 4 at a pressure of the order of 1.3 bar, sufficient for it to be used for the regeneration of the adsorption bottles (not shown) serving purifying the incoming air.
  • This is advantageous but results in a relatively high operating pressure, which is costly in terms of compression energy of the incoming air.
  • the rolling of air in the valve 20 corresponds to a loss of energy.
  • FIG. 7 takes up the principle of FIG. 5 but makes it possible to avoid any rolling of air and to lower the operating pressure: the column 18 is transferred under the column 3, in the same shell; it is supplied at the head by the lean liquid falling from the section K1 and by an addition of lean liquid LP drawn off at the top of the column 5 and expanded in a valve 21, and in the tank by all of the air expanded to 1.8 bar in the turbine 19. Since this flow rate provides an impure nitrogen flow rate at the head of the column 18 greater than that necessary for the operation of the column 3, it is possible to draw from it an additional residual gas R, under approximately 1 , 6 bar, which can be used for the regeneration of the aforementioned adsorption bottles. The gas R1 leaving the minaret 4 is no longer used for this regeneration and need only be at a pressure slightly higher than atmospheric pressure, to overcome the pressure losses of the heat exchange line used for cooling incoming air. The system operating pressure is thus lowered.
  • FIG. 7 shows the source and the use of the two types of rich liquid: (a) rich liquid with argon, originating on the one hand from the tank of the medium pressure column 5, on the other hand from the tank of the column 18. These two flows are combined and serve both to reflux into the low pressure column 6 and to supply the head condenser 2A of the column 2, in a conventional manner; and (b) rich liquid LR1 without argon, taken between the sections K1 and K2 of column 3 and sent to the head of minaret 4. Furthermore, by comparing this FIG. 7 with FIG. 1, it can be seen that one performs between the sections K1 and K2 the two withdrawals indicated in FIG. 1, namely a direct withdrawal of waste gas R and a withdrawal of liquid LR1 which, after mixing with nitrogen, also supplies waste gas R1, but at a pressure different.
  • FIG. 7 also shows pipes for drawing off gaseous oxygen or low pressure liquid from column 6 and nitrogen gas or medium pressure liquid from column 5.
  • FIG. 8 Another possibility to avoid any loss of energy by air rolling is illustrated by the installation of FIG. 8.
  • the double column 5,6 surmounted by the minaret 4 constituting the section K3 of FIG. 1
  • the turbined air in the turbine 19 is expanded to 1.3 bar and blown into column 6.
  • two auxiliary columns are used: on the one hand, a column 3A, operating at 1.4 bar, which joins the column 14 for purifying oxygen and, under it, the section K2 of FIG. 1, and on the other hand a column 3B, operating at 1.5 bar, which joins the section K1 of FIG. 1 and, under this one, a splitting 6A of the upper part of the low pressure column 6.
  • the section K2 is supplied at the head with liquid oxygen withdrawn from the tank of column 6 and, in the tank, by gas G withdrawn at the head of column 3B, that is to say at the head of the section K1.
  • Rich liquid without argon LR1 withdrawn from the bottom of column 3A, is sent under reflux both at the top of column 3B and minaret 4.
  • Poor liquid is sent under reflux both at the top of column 6 and of section 6A, while the liquid rich with argon coming from the tank of column 5 is, in part, injected both into column 6 and into section 6A, and, for another part, vaporized in the condenser of head 2A of column 2 then injected into the tank of section 6A.
  • the very rich liquid collected at the bottom of the latter is in turn injected into column 6.
  • FIG. 8 Pressure drop considerations show that the arrangement of FIG. 8 is particularly suitable in the case where at least column 2 is fitted with packings. Furthermore, it is understood that the installation of FIG. 8 could also operate by replacing the air trigger with a nitrogen trigger.
  • FIG. 9 shows another installation in which the sections K1 and K3 both operate at the pressure of the low pressure column 6 and are combined.
  • the double column is surmounted by a remixing column 3B supplied at the head with liquid oxygen originating from the tank of column 6 and into the tank by the impure nitrogen at the top of this same column 6.
  • the tank liquid from column 3B is refluxed into column 6, and impure oxygen is drawn off at the top from column 3B.
  • the residual gas R is drawn off between the sections K2 on the one hand, K1-K3 on the other hand.
  • the invention is compatible not only with double column installations, but also with any type of air distillation installation comprising means for producing argon.
  • An example of such a simple column installation is illustrated in FIG. 10, which is a more complete diagram than FIGS. 2 to 9.
  • the air, compressed and purified, is cooled and partially liquefied in a heat exchange line 20.
  • the majority of the air flow is expanded to 1.5 bar in a turbine 21 (Claude cycle), then injected into the simple distillation column 1A connected to column 2 for the production of argon.
  • the liquefied air, expanded in a valve 22, is injected into the same column. This produces oxygen in the tank and nitrogen at the top.
  • This latter gas after heating in the exchange line 20, is partially compressed to 6 bars by a compressor 23, cooled and passes through a coil 24 provided in the tank of column 1A, where it condenses by vaporizing the liquid oxygen, then it is partially expanded in a valve 25 and sent under reflux to the top of the column 1A.
  • the rest of the condensed nitrogen is expanded in a valve 26, vaporized in the condenser at the head of column 2 then sent to the tank of the mixing column 3, bringing together the sections K1 and K2, which operates at 2 to 3 bars.
  • the liquid oxygen produced in the tank of column 1A is at least partly brought by pump to the pressure of column 3 and injected at the top of the latter.
  • the impure gaseous oxygen withdrawn at the head of column 3 is condensed in a second coil 27 in the tank of column 1A, expanded in a valve 28 and injected into this same column 1A.
  • the section K3 located above the column 1A is supplied at the top by the rich liquid LR1 drawn off between the sections K1 and K2 and expanded at low pressure, and in the tank by the nitrogen at the top of the column 1A.
  • This section K3 produces in the tank lean liquid LP2 which, like the lean liquid LP1 coming from the tank of column 3, is sent under reflux at the top of column 1A; it produces the waste gas R1 at the head, which is heated in the exchange line 20 before being evacuated or, if the pressure is sufficient, used to regenerate the bottles of adsorbent used to purify the incoming air .
  • the installation can also produce liquid oxygen, drawn off from the bottom of column 1A, gaseous oxygen, also drawn off from the bottom of this column and heated in the exchange line 20, and nitrogen gas, drawn off at the top of the same column and, after heating, discharged upstream of the compressor 23.
  • nitrogen can also be taken at 6 bars downstream of the compressor 23.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

Liquid oxygen (OL) and nitrogen gas (N2MP) are remixed in an almost reversible way into an auxiliary column (3); argon-free rich liquid (LR1) taken at an intermediate location from said auxiliary column (3) is remixed in another auxiliary column section (4) with impure nitrogen of the head of the low pressure column (6), and the head gas of said auxiliary section forms a residue (R1) of the plant. Application to the production of argon.

Description

La présente invention est relative à la technique de distillation de l'air au moyen d'une installation munie d'une colonne de production d'argon.The present invention relates to the air distillation technique by means of an installation provided with an argon production column.

Comme il est bien connu, les installations de distillation d'air munies d'une colonne de production d'argon comprennent généralement une double colonne constituée d'une colonne de distillation moyenne pression fonctionnant sous environ 6 bars, d'une colonne de distillation basse pression fonctionnant un peu au-dessus de la pression atmosphérique, et d'un condenseur-vaporiseur. L'air est envoyé, après épuration et refroidissement, en cuve de la colonne moyenne pression. Le « liquide riche (air enrichi en oxygène) recueilli en cuve de la colonne moyenne pression est envoyé en alimentation en un point intermédiaire de la colonne basse pression, tandis qu'une partie du « liquide pauvre », constitué presque entièrement d'azote, recueilli en tête de la colonne moyenne pression est envoyé en reflux en tête de la colonne basse pression. Au-dessous de l'entrée du liquide riche, la colonne basse pression est reliée à la colonne de production d'argon par une conduite dite de « piquage argon et une conduite de retour de liquide moins riche en argon. La colonne basse pression est généralement munie en cuve de conduites de soutirage d'oxygène gazeux et d'oxygène liquide, et la colonne moyenne pression est généralement munie en tête de conduites de soutirage d'azote gazeux et d'azote liquide. La vapeur de tête de la colonne basse pression (« azote impur ») est constituée d'azote contenant jusqu'à quelques % d'oxygène et est généralement rejetée à l'atmosphère.As is well known, air distillation installations provided with an argon production column generally comprise a double column consisting of a medium pressure distillation column operating at about 6 bars, of a low distillation column pressure operating slightly above atmospheric pressure, and a condenser-vaporizer. The air is sent, after purification and cooling, to the tank of the medium pressure column. The “rich liquid (oxygen-enriched air) collected in the bottom of the medium pressure column is sent to the feed at an intermediate point in the low pressure column, while part of the“ poor liquid ”, consisting almost entirely of nitrogen, collected at the head of the medium pressure column is sent to reflux at the head of the low pressure column. Below the inlet for the rich liquid, the low-pressure column is connected to the argon production column by a pipe called “argon tapping and a return pipe for liquid less rich in argon. The low pressure column is generally provided in the tank with gaseous oxygen and liquid oxygen withdrawal pipes, and the medium pressure column is generally provided at the head with gaseous nitrogen and liquid nitrogen withdrawal pipes. The vapor at the top of the low pressure column (“impure nitrogen”) consists of nitrogen containing up to a few% of oxygen and is generally discharged into the atmosphere.

Dans les installations destinées essentiellement à produire de l'oxygène gazeux délivré directement à un utilisateur par canalisation, il arrive que l'oxygène soit temporairement excédentaire. C'est le cas notamment pendant les périodes d'arrêt des usines de l'utilisateur. Avec les installations classiques de distillation, l'oxygène gazeux est alors mis à l'atmosphère, et l'énergie dépensée pour la séparation de cet oxygène est perdue. Le FR-A-2 550 325 propose une solution pour limiter cet inconvénient. Cette solution a l'avantage d'être simple, mais son efficacité est limitée.In installations intended essentially to produce gaseous oxygen supplied directly to a user by pipeline, it sometimes happens that the oxygen is temporarily excess. This is particularly the case during periods of shutdown of the user's factories. With conventional distillation installations, the gaseous oxygen is then put into the atmosphere, and the energy expended for the separation of this oxygen is lost. FR-A-2 550 325 proposes a solution to limit this drawback. This solution has the advantage of being simple, but its effectiveness is limited.

Plus généralement, la distillation d'un débit d'air donné est capable de fournir environ 21 % de ce débit en oxygène et, dans certaines conditions, cette quantité d'oxygène est excédentaire par rapport aux besoins réels, alors que d'autres productions, notamment l'argon, sont recherchées.More generally, the distillation of a given air flow is capable of supplying approximately 21% of this oxygen flow and, under certain conditions, this quantity of oxygen is in excess of actual needs, while other productions , including argon, are sought after.

L'invention a pour but de permettre dans tous les cas de valoriser de façon optimale l'excès d'oxygène pour augmenter les productions souhaitées, en particulier celle d'argon.The object of the invention is to make it possible in all cases to optimize the excess oxygen in order to increase the desired productions, in particular that of argon.

A cet effet, l'invention a pour objet un procédé de distillation d'air au moyen d'une installation comprenant un appareil principal de distillation associé à une colonne de production d'argon par une conduite de piquage argon, ce procédé étant tel que défini dans la revendication 1.To this end, the subject of the invention is a process for the distillation of air by means of an installation comprising a main distillation apparatus associated with an argon production column by an argon tapping pipe, this process being such that defined in claim 1.

L'invention a également pour objet une installation destinée à la mise en oeuvre d'un tel procédé. Cette installation est telle que définie dans la revendication 13.The invention also relates to an installation intended for the implementation of such a method. This installation is as defined in claim 13.

Il est à noter que le FR-A-2 169 561 montre d'autres manières de mettre à profit l'énergie récupérée par remélange de fluides. Ce document décrit un procédé et une installation de distillation d'air au moyen d'une installation comprenant un appareil principal de distillation associé à une colonne de production d'argon par une conduite de piquage argon, dans lesquelles

  • - on envoie à la base d'un premier tronçon de colonne de mélange un fluide volatil, et au sommet d'un second tronçon de colonne de mélange de l'oxygène liquide éventuellement impur ;
  • - on envoie à la base du deuxième tronçon une partie au moins de la vapeur de tête du premier tronçon et au sommet du premier tronçon une partie au moins du liquide produit à la base du second tronçon ;
  • - on effectue entre la base du premier tronçon et le sommet du second tronçon au moins un soutirage intermédiaire ;
  • - on évacue du second tronçon, en tête de celui-ci de l'oxygène impur ; et
  • - on évacue du premier tronçon, à la base de celui-ci, du liquide, qu'on envoie en reflux dans l'appareil principal de distillation.
It should be noted that FR-A-2 169 561 shows other ways of making use of the energy recovered by remixing fluids. This document describes a process and an installation for the distillation of air by means of an installation comprising a main distillation apparatus associated with an argon production column by an argon tapping pipe, in which
  • - Is sent to the base of a first section of mixing column volatile fluid, and to the top of a second section of mixing column of possibly impure liquid oxygen;
  • - Is sent to the base of the second section at least part of the overhead vapor of the first section and at the top of the first section at least part of the liquid produced at the base of the second section;
  • - Between the base of the first section and the top of the second section, at least one intermediate racking is carried out;
  • - Evacuates from the second section, at the head thereof impure oxygen; and
  • - Evacuates from the first section, at the base thereof, liquid, which is sent under reflux into the main distillation apparatus.

Quelques exemples de mise - en oeuvre de l'invention vont maintenant être décrits en regard des dessins annexés, sur lesquels :

  • - la figure 1 est un diagramme qui illustre le principe de base de l'invention ;
  • - la figure 2 représente schématiquement une installation de distillation d'air conforme à l'invention ;
  • - la figure 3 représente schématiquement une partie d'une variante de l'installation de la figure 2 ; et
  • - les figures 4 à 10 représentent schématiquement d'autres modes de réalisation de l'installation suivant l'invention.
Some examples of implementation of the invention will now be described with reference to the appended drawings, in which:
  • - Figure 1 is a diagram which illustrates the basic principle of the invention;
  • - Figure 2 schematically shows an air distillation installation according to the invention;
  • - Figure 3 schematically shows part of a variant of the installation of Figure 2; and
  • - Figures 4 to 10 schematically show other embodiments of the installation according to the invention.

Dans tout ce qui suit, on appelle « colonne » ou « tronçon de colonne un appareil d'échange de matière et de chaleur ayant la structure d'une colonne de distillation, c'est-à-dire comportant un garnissage ou un certain nombre de plateaux du type de ceux utilisés en distillation.In what follows, a “column” or “section of a column is a material and heat exchange apparatus having the structure of a distillation column, that is to say comprising a packing or a certain number of trays of the type used in distillation.

La figure 1 illustre par un diagramme la manière dont une installation classique de distillation d'air, représentée plus en détail sur les autres figures, est modifiée conformément à l'invention.Figure 1 illustrates by a diagram how a conventional air distillation installation, shown in more detail in the other figures, is modified according to the invention.

On adjoint à l'installation classique au moins deux tronçons de colonne de mélange K1 et K2, fonctionnant sous deux pressions P1 et P2 qui, comme on le verra plus loin, peuvènt être ou non égalesAt least two sections of mixing column K1 and K2 are added to the conventional installation, operating under two pressures P1 and P2 which, as will be seen below, may or may not be equal.

Le tronçon K1 est alimenté à sa base par de l'azote gazeux pouvant contenir jusqu'à quelques % d'oxygène mais pratiquement dépourvu d'argon (c'est-à-dire contenant moins de 1 % d'argon, et de préférence moins de 0,05 % d'argon), tandis que le tronçon K2 est alimenté à son sommet par de l'oxygène liquide pratiquement dépourvu d'argon (avec .la même signification que précédemment) et d'azote. La vapeur de tête du tronçon K1 est envoyée à la base du tronçon K2, et le liquide de cuve de ce dernier est envoyé en reflux au sommet du tronçon K1. A la base de ce dernier, on soutire du liquide pauvre LP1, constitué d'azote contenant jusqu'à quelques % d'oxygène, et on soutire au sommet du tronçon K2 de l'oxygène impur, c'est-à-dire contenant jusqu'à 15 % environ d'azote, et de préférence de 5 à 10 % environ d'azote.The K1 section is supplied at its base with nitrogen gas which can contain up to a few % of oxygen but practically devoid of argon (that is to say containing less than 1% of argon, and preferably less than 0.05% of argon), while the section K2 is supplied at its summit by liquid oxygen practically devoid of argon (with the same meaning as above) and nitrogen. The head vapor of the section K1 is sent to the base of the section K2, and the tank liquid of the latter is sent in reflux to the top of the section K1. At the base of the latter, lean liquid LP1, consisting of nitrogen containing up to a few% of oxygen, is drawn off and impure oxygen, that is to say containing, is drawn off at the top of the section K2. up to about 15% nitrogen, and preferably about 5-10% nitrogen.

Pour permettre ces deux soutirages, on effectue au moins un soutirage intermédiaire entre la base du tronçon K1 et le sommet du tronçon K2, pour constituer un gaz résiduaire de l'installation composé d'un mélange oxygène-azote à environ 10 à 30 % d'oxygène, et donc ayant une composition voisine de celle de l'air mais dépourvu d'argon.To allow these two withdrawals, at least one intermediate withdrawal is carried out between the base of the section K1 and the top of the section K2, to constitute a residual gas from the installation composed of an oxygen-nitrogen mixture at approximately 10 to 30% d oxygen, and therefore having a composition close to that of air but devoid of argon.

Dans l'exemple illustré à la figure 1, le soutirage intermédiaire est effectué entre les tronçons K1 et K2. Il peut être constitué par de la vapeur de tête du tronçon K1, ce qui fournit directement le gaz résiduaire R. Dans certains cas, il peut être préférable de soutirer du liquide de cuve LR1 du tronçon K2, ce liquide étant constitué d'un mélange oxygène-azote à une teneur de 40 à 75 % d'oxygène environ ; ce liquide est alors envoyé en tête d'un troisième tronçon de colonne de mélange K3, fonctionnant sous une pression P3 et alimenté à sa base, comme le tronçon K1, par de l'azote gazeux éventuellement impur mais pratiquement sans argon. On soutire alors le gaz résiduaire R1 en tête du tronçon K3, tandis que le liquide de cuve de ce tronçon constitue du liquide pauvre LP2 constitué, comme le liquide LP1, d'azote contenant jusqu'à quelques % d'oxygène.In the example illustrated in FIG. 1, the intermediate racking is carried out between the sections K1 and K2. It can be constituted by overhead steam from section K1, which directly supplies the residual gas R. In certain cases, it may be preferable to draw tank liquid LR1 from section K2, this liquid being made up of a mixture oxygen-nitrogen with a content of approximately 40 to 75% of oxygen; this liquid is then sent to the head of a third section of mixing column K3, operating under a pressure P3 and supplied at its base, like the section K1, with nitrogen gas which is possibly impure but practically without argon. The residual gas R1 is then drawn off at the head of the section K3, while the tank liquid of this section constitutes lean liquid LP2 consisting, like the liquid LP1, of nitrogen containing up to a few% of oxygen.

Les liquides LP1 et LP2 sont envoyés en reflux dans l'installation pour y améliorer la distillation ; l'oxygène gazeux impur soutiré en tête du tronçon K2 peut constituer un gaz de production, ou être épuré pour produire de l'oxygène gazeux pur, comme on le verra plus loin. La provenance de l'oxygène liquide et du ou des flux d'azote gazeux apparaîtra dans la suite de la description.The LP1 and LP2 liquids are sent back to the installation to improve the distillation; the impure gaseous oxygen withdrawn at the head of the section K2 can constitute a production gas, or be purified to produce pure gaseous oxygen, as will be seen below. The source of the liquid oxygen and of the nitrogen gas stream (s) will appear in the following description.

Si les pressions P1, P2 et P3 diffèrent entre elles, on utilisera des organes de détente appropriés (vannes ou turbines) entre les tronçons de colonne de mélange. Par ailleurs, si P1 = P3, les tronçons K1 et K3 fonctionnent dans des conditions identiques et peuvent être confondus en un seul tronçon de colonne, comme on le verra plus loin en regard de la figure 9.If the pressures P1, P2 and P3 differ from one another, appropriate expansion devices (valves or turbines) will be used between the sections of the mixing column. Furthermore, if P1 = P3, the sections K1 and K3 operate under identical conditions and can be combined into a single column section, as will be seen below with reference to FIG. 9.

Dans tous les cas, le schéma de la figure 1 assure un remélange d'oxygène liquide et d'azote gazeux, tous deux à peu près exempts d'argon, dans des conditions proches de la réversibilité, ce qui correspond à une récupération d'énergie. Cette énergie se manifeste sous forme d'un transfert frigorifique du type pompe à chaleur entre l'oxygène liquide et le liquide pauvre LP1-LP2 et peut être mise à profit pour augmenter les productions de l'installation autres que l'oxygène, à savoir l'azote gazeux sous pression, les productions liquides et surtout l'argon, comme cela apparaîtra dans la suite de la description. On remarque que l'effet technique ci-dessus serait également obtenu en alimentant le sommet du tronçon K2 avec de l'oxygène liquide contenant jusqu'à quelques % d'azote comme impureté.In all cases, the diagram in FIG. 1 ensures a remixing of liquid oxygen and nitrogen gas, both almost free of argon, under conditions close to reversibility, which corresponds to recovery of energy. This energy manifests itself in the form of a heat pump type refrigeration transfer between the liquid oxygen and the lean liquid LP1-LP2 and can be used to increase the production of the installation other than oxygen, namely nitrogen gas under pressure, liquid productions and especially argon, as will appear in the following description. It is noted that the above technical effect would also be obtained by supplying the top of the section K2 with liquid oxygen containing up to a few% of nitrogen as an impurity.

Les figures 2 à 9 montrent plusieurs exemples de mise en oeuvre du principe de base illustré à la figure 1 avec des installations de distillation d'air à double colonne. Sur ces figures, on a omis de représenter certaines conduites et éléments classiques (notamment les échangeurs de chaleur) des installations à double colonne, dans un but de clarté des dessins.Figures 2 to 9 show several examples of implementation of the basic principle illustrated in Figure 1 with double column air distillation plants. In these figures, we have omitted to represent certain conventional pipes and elements (in particular heat exchangers) of double column installations, for the sake of clarity of the drawings.

L'installation de distillation d'air représentée à la figure 2 est destinée à produire d'une part de l'oxygène impur contenant environ 5 à 10 % d'azote, d'autre part de l'argon, et éventuellement de l'azote. Elle comprend essentiellement une double colonne 1, une colonne 2 de production d'argon, une colonne de remélange 3 et un minaret de remélange 4.The air distillation installation shown in FIG. 2 is intended to produce, on the one hand, impure oxygen containing approximately 5 to 10% nitrogen, on the other hand, argon, and optionally nitrogen. It essentially comprises a double column 1, an argon production column 2, a remixing column 3 and a remixing minaret 4.

La double colonne 1 comprend, de façon classique, une colonne inférieure 5 fonctionnant sous une moyenne pression MP de l'ordre de 6 bars absolus, une colonne supérieure 6 fonctionnant sous une basse pression BP légèrement supérieure à la pression atmosphérique, et un vaporiseur-condenseur 7 qui met en relation d'échange thermique le liquide de cuve (oxygène liquide pratiquement pur) de la colonne basse pression avec la vapeur de tête (azote pratiquement pur) de la colonne moyenne pression.The double column 1 comprises, in a conventional manner, a lower column 5 operating under a medium pressure MP of the order of 6 bar absolute, an upper column 6 operating under a low pressure BP slightly above atmospheric pressure, and a vaporizer- condenser 7 which puts in heat exchange relation the tank liquid (practically pure liquid oxygen) of the low pressure column with the overhead vapor (practically pure nitrogen) of the medium pressure column.

L'air à traiter, comprimé à 6 bars, épuré et refroidi au voisinage de son point de rosée, est injecté au bas de la colonne moyenne pression. Le liquide de cuve de cette colonne, riche en oxygène (liquide riche LR à environ 40% d'oxygène) contient la quasi-totalité de l'oxygène et de l'argon de l'air entrant ; il est détendu et injecté en 8 en un emplacement intermédiaire de la colonne basse pression, tandis que du liquide de tête de la colonne 5 (liquide pauvre en oxygène, LP), est détendu et injecté en 9 au sommet de la colonne basse pression.The air to be treated, compressed to 6 bars, purified and cooled near its dew point, is injected at the bottom of the medium pressure column. The tank liquid in this column, rich in oxygen (rich liquid LR at about 40% oxygen) contains almost all of the oxygen and argon in the incoming air; it is expanded and injected at 8 at an intermediate location of the low pressure column, while liquid from the top of column 5 (liquid poor in oxygen, LP), is expanded and injected at 9 at the top of the low pressure column.

Au-dessous du point 8, une conduite 10 de piquage argon envoie un gaz à peu près dépourvu d'azote dans la colonne 2, et une conduite 11 ramène le liquide de cuve de cette dernière, un peu moins riche en argon, à peu près au même niveau dans la colonne basse pression. L'argon impur (mixture argon) est extrait du sommet de la colonne 2 et est ensuite épuré de façon classique.Below point 8, a pipe 10 for argon tapping sends a gas almost free of nitrogen to column 2, and a pipe 11 brings the tank liquid from the latter, slightly less rich in argon, at about near the same level in the low pressure column. The impure argon (argon mixture) is extracted from the top of column 2 and is then purified in a conventional manner.

La colonne 3 fonctionne sous la moyenne pression de l'installation et réunit les tronçons de colonne de mélange K1 et K2 de la figure 1, avec P1 = P2. Elle est alimentée à sa base en azote prélevé-en tête de la colonne moyenne pression 5, et en tête par de l'oxygène liquide prélevé en cuve de la colonne basse pression 6 et amené à la moyenne pression par une pompe 12.Column 3 operates under the medium pressure of the installation and brings together the sections of mixing column K1 and K2 in FIG. 1, with P1 = P2. It is supplied at its base with nitrogen taken from the head of the medium pressure column 5, and at the head with liquid oxygen taken from the bottom of the low pressure column 6 and brought to medium pressure by a pump 12.

Dans la colonne 3, l'oxygène liquide descendant et l'azote gazeux montant se remélangent d'une façon relativement réversible, de sorte que l'on obtient :

  • - en cuve de la colonne 3, du liquide pauvre supplémentaire LP1, constitué d'azote contenant jusqu'à quelques % d'oxygène, qui peut être adjoint au liquide pauvre issu de la colonne moyenne pression pour augmenter en 9 le reflux dans la colonne basse pression ;
  • - en tête de la colonne 3, de l'oxygène gazeux impur (oxygène contenant moins de 15 % d'azote, par exemple 5 à 10 % environ d'azote) sous 6 bars ; et
  • - en un emplacement intermédiaire de la colonne 3, qui peut être considéré comme situé entre les tronçons inférieur K1 et supérieur K2 de la colonne 3, du liquide riche LR1 constitué d'un mélange d'azote et d'oxygène à une teneur qui dépend du niveau du soutirage, cette teneur pouvant varier par exemple de 40 à 75 % en oxygène et étant par exemple voisine de celle du liquide riche LR.
In column 3, the falling liquid oxygen and the rising nitrogen gas mix in a relatively reversible manner, so that:
  • - in the tank of column 3, additional lean liquid LP1, consisting of nitrogen containing up to a few% of oxygen, which can be added to the lean liquid from the medium pressure column to increase the reflux in the column at 9 low pressure ;
  • - At the head of column 3, impure gaseous oxygen (oxygen containing less than 15% of nitrogen, for example 5 to 10% of nitrogen) at 6 bars; and
  • - at an intermediate location in column 3, which can be considered to be located between the lower K1 and upper K2 sections of column 3, of the rich liquid LR1 consisting of a mixture of nitrogen and oxygen at a content which depends the level of withdrawal, this content being able to vary for example from 40 to 75% in oxygen and being for example close to that of the rich liquid LR.

Comme les deux fluides introduits en tête et en cuve de la colonne 3 sont pratiquement exempts d'argon, il en est de même des trois fluides soutirés de cette colonne. En particulier, l'oxygène impur ainsi produit contient pratiquement uniquement de l'azote comme impureté.As the two fluids introduced at the head and into the tank of column 3 are practically free of argon, the same is true of the three fluids withdrawn from this column. In particular, the impure oxygen thus produced contains practically only nitrogen as an impurity.

Le minaret de remélange 4 constitue le tronçon de colonne de mélange K3 de la figure 1. Sa base communique directement avec le sommet de la colonne basse pression 6. Il est donc alimenté à sa base par de l'azote impur (azote contenant jusqu'à quelques % d'oxygène). A son sommet, ce minaret est alimenté en 13 par le liquide riche LR1 provenant de la colonne 3 et convenablement détendu. Le remélange relativement réversible de l'azote impur et du liquide riche LR1 produit une quantité supplémentaire de liquide pauvre LP2, constitué d'azote contenant jusqu'à quelques % d'oxygène, qui tombe dans la colonne 6 et y augmente le reflux. En tête du minaret 4, on évacue le gaz résiduaire R1 dépourvu d'argon et dont la composition est voisine de celle de l'air.The remixing minaret 4 constitutes the section of mixing column K3 in FIG. 1. Its base communicates directly with the top of the low pressure column 6. It is therefore supplied at its base with impure nitrogen (nitrogen containing up to to a few% of oxygen). At its summit, this minaret is supplied with 13 by the rich liquid LR1 coming from column 3 and suitably expanded. The relatively reversible remixing of the impure nitrogen and the rich liquid LR1 produces an additional quantity of poor liquid LP2, consisting of nitrogen containing up to a few% of oxygen, which falls into column 6 and increases the reflux there. At the head of minaret 4, the waste gas R1 devoid of argon and whose composition is close to that of air is evacuated.

Comme il est classique, une partie du liquide riche LR ou LR1 peut être détendue et vaporisée dans un condenseur de tête de la colonne 2, puis renvoyée dans la colonne 6 au voisinage du niveau 8. Par ailleurs, comme représenté, une partie de la vapeur de tête de la colonne 6 peut être soutiré, par exemple pour produire par distillation dans un tronçon de colonne auxiliaire (non représenté) de l'azote pur sous la basse pression.As is conventional, part of the rich liquid LR or LR1 can be expanded and vaporized in a condenser at the head of column 2, then returned to column 6 near level 8. Furthermore, as shown, part of the vapor from the top of column 6 can be withdrawn, for example to produce by distillation in an auxiliary column section (not shown) pure nitrogen under low pressure.

En supposant que la totalité de l'oxygène liquide produit dans la colonne 6 est envoyée dans la colonne 3, l'installation de la figure 2 permet de produire, outre l'argon, de l'azote et de l'oxygène impur. Pour obtenir de l'oxygène pur, qui sera soutiré de façon classique au bas de la colonne basse pression, on peut utiliser le schéma de la figure 3, qui présente l'avantage de ne pas perturber le fonctionnement de la colonne 2 de production d'argon.Assuming that all of the liquid oxygen produced in column 6 is sent to column 3, the installation in FIG. 2 makes it possible to produce, in addition to argon, nitrogen and impure oxygen. To obtain pure oxygen, which will be drawn off in a conventional manner at the bottom of the low pressure column, the diagram in FIG. 3 can be used, which has the advantage of not disturbing the operation of column 2 for the production of 'argon.

Sur cette figure 3, on voit que du liquide est prélevé dans la colonne basse pression, quelques plateaux au-dessus du piquage argon 10, et envoyé en tête d'une colonne basse pression auxiliaire 14 ; cette dernière est alimentée à sa base par l'oxygène impur issu de la colonne de mélange 3, détendu à la basse pression dans une turbine 15. Le liquide de cuve de la colonne 14 est de l'oxygène impur sans argon, que l'on adjoint en amont de la pompe 12 à l'oxygène liquide pur soutiré de la colonne basse pression. Tout l'argon contenu dans le liquide injecté en tête de la colonne 14 repart avec la vapeur de tête de cette colonne et est renvoyé dans la colonne basse pression 6, à peu près au même niveau que le soutirage dudit liquide.In this FIG. 3, it can be seen that liquid is taken from the low pressure column, a few trays above the argon tapping 10, and sent to the head of an auxiliary low pressure column 14; the latter is supplied at its base with impure oxygen from the mixing column 3, expanded at low pressure in a turbine 15. The bottom liquid of the column 14 is impure oxygen without argon, that the is added upstream of the pump 12 to the pure liquid oxygen withdrawn from the low pressure column. All the argon contained in the liquid injected at the top of the column 14 leaves with the overhead vapor of this column and is returned to the low pressure column 6, at about the same level as the withdrawal of said liquid.

Ainsi, dans la colonne 14, on effectue une séparation de l'oxygène et de l'argon, parallèle à celle qui se produit dans la partie inférieure de la colonne 6, mais en présence d'un ballast de 5 à 10 % d'azote. La quantité d'oxygène liquide renvoyée de la cuve de la colonne 14 vers la colonne 3 n'a plus besoin d'être soutirée de la cuve de la colonne 6, ce qui permet de soutirer à la base de celle-ci la même quantité d'oxygène pur en tant que produit.Thus, in column 14, a separation of oxygen and argon is carried out, parallel to that which occurs in the lower part of column 6, but in the presence of a ballast of 5 to 10% of nitrogen. The quantity of liquid oxygen returned from the tank of column 14 to column 3 no longer needs to be withdrawn from the tank of column 6, which makes it possible to withdraw the same amount from its base. pure oxygen as a product.

Dans les installations des figures 2 et 3, le soutirage d'oxygène liquide en cuve de la colonne 6 pour alimenter la colonne 3 équivaut à une augmentation du chauffage de cette colonne. On a donc, dans la colonne 6, à la fois une augmentation du reflux en tête et du chauffage en cuve ; la distillation y est par suite améliorée, ce qui peut être mis à profit pour augmenter le rendement d'extraction en argon et/ou les productions de l'installation autres que l'oxygène gazeux : l'azote moyenne pression complémentaire peut être utilisé directement comme produit sous pression, ou turbiné pour produire du froid et donc augmenter la production de liquide (azote liquide ou oxygène liquide) de l'installation. L'augmentation de la production de liquide de l'installation peut d'ailleurs être obtenue d'une autre manière, dans les installations à insufflation d'air dans la colonne basse pression, en augmentant le débit d'air turbiné. Ces diverses possibilités sont illustrées par les figures 4 à 8. On peut également envisager, dans le même but, de turbiner un débit de gaz résiduaire R soutiré en un emplacement intermédiaire de la colonne 3, comme représenté à la figure 3.In the installations of FIGS. 2 and 3, the withdrawal of liquid oxygen from the tank of column 6 to supply column 3 is equivalent to an increase in the heating of this column. In column 6, therefore, there is both an increase in reflux at the top and heating in the tank; the distillation is consequently improved there, which can be used to increase the extraction yield of argon and / or the production of the installation other than gaseous oxygen: the additional medium pressure nitrogen can be used directly as a pressurized product, or turbined to produce cold and therefore increase the production of liquid (liquid nitrogen or liquid oxygen) from the installation. The increase in the liquid production of the installation can moreover be obtained in another way, in installations with air insufflation in the low pressure column, by increasing the flow of turbinated air. These various possibilities are illustrated by FIGS. 4 to 8. It is also possible, for the same purpose, to turbinate a flow of residual gas R withdrawn at an intermediate location of the column 3, as shown in FIG. 3.

A la figure 4, la colonne 3 fonctionne au voisinage de la basse pression et reçoit directement en tête de l'oxygène liquide provenant de la cuve de la colonne 6. Par suite, la turbine 15 de la figure 3 est supprimée et les colonnes 3 et 14 sont réunies dans une seule virole 16. La cuve de la colonne 3 est alimentée par de l'azote obtenu par détente dans une turbine 17 d'azote moyenne pression. Comme représenté, de l'azote moyenne pression détendu dans la turbine 17 puis dans une vanne de détente 17A peut également être insufflé en tête de la colonne 6.In FIG. 4, the column 3 operates in the vicinity of the low pressure and directly receives at the head liquid oxygen coming from the tank of the column 6. As a result, the turbine 15 of FIG. 3 is eliminated and the columns 3 and 14 are combined in a single ferrule 16. The tank of column 3 is supplied with nitrogen obtained by expansion in a turbine 17 of medium pressure nitrogen. As shown, medium pressure nitrogen expanded in the turbine 17 and then in an expansion valve 17A can also be blown at the head of the column 6.

A la figure 5 est indiqué un autre moyen pour fournir de l'azote basse pression à la base de la colonne 3 : la partie supérieure de la colonne 6 est dédoublée par une colonne auxiliaire 18 fonctionnant sous une pression quelque peu supérieure, par exemple 1,8 bar contre 1,4 bar pour la colonne 6.FIG. 5 shows another means of supplying low pressure nitrogen at the base of column 3: the upper part of column 6 is split by an auxiliary column 18 operating at a somewhat higher pressure, for example 1.8 bar against 1.4 bar for column 6.

Une partie du débit d'air traité est dérivée et détendue à 1,8 bar dans une turbine 19. Une partie du débit turbiné est envoyée à la base de la colonne 18, iaquelle reçoit en tête, comme la colonne 6, du liquide pauvre à la pression convenable. Le reste de l'air turbiné est détendu à 1,4 bar dans une vanne de détente 20 et insufflé dans la colonne 6, de même que le liquide de cuve de la colonne 18. C'est l'azote impur, contenant jusqu'à quelques % d'oxygène et pratiquement pas d'argon, soutiré en tête de la colonne 18, qui est utilisé pour alimenter la base de la colonne 3.Part of the treated air flow is diverted and expanded to 1.8 bar in a turbine 19. Part of the turbinated flow is sent to the base of column 18, which receives at the head, like column 6, lean liquid at the correct pressure. The rest of the turbined air is expanded to 1.4 bar in an expansion valve 20 and blown into column 6, as is the tank liquid in column 18. It is impure nitrogen, containing up to at a few% of oxygen and practically no argon, withdrawn at the head of column 18, which is used to feed the base of column 3.

La figure 6 illustre une variante de la figure 5 qui permet de supprimer la pompe (non représentée) de remontée du liquide LP1. Pour cela, le tronçon K1 est reporté au-dessus de la colonne 18, dans la même virole que celle-ci, et le liquide LR1 est partagé entre le sommet du minaret 4 et celui du tronçon K1. En variante, on peut supprimer la conduite pourvue de la vanne 20 et distiller tout l'air turbiné dans la colonne 18. On produit alors en tête du tronçon K1 un second gaz résiduaire R, comme indiqué en trait mixte à la figure 6.Figure 6 illustrates a variant of Figure 5 which eliminates the pump (not shown) for raising the liquid LP1. For this, the section K1 is transferred above the column 18, in the same shell as the latter, and the liquid LR1 is shared between the top of the minaret 4 and that of the section K1. As a variant, it is possible to remove the pipe provided with the valve 20 and to distil all the turbinated air in the column 18. A second waste gas R is then produced at the head of the section K1, as indicated in phantom in FIG. 6.

Dans les installations des figures 5 et 6, le gaz résiduaire R1 sort du minaret 4 à une pression de l'ordre de 1,3 bar, suffisante pour qu'il soit utilisé pour la régénération des bouteilles d'adsorption (non représentées) servant à l'épuration de l'air entrant. Ceci est avantageux mais conduit à une pression de marche relativement élevée, ce qui est coûteux en énergie de compression de l'air entrant. De plus, lorsqu'on y fait appel, le laminage d'air dans la vanne 20 correspond à une perte d'énergie.In the installations of FIGS. 5 and 6, the residual gas R1 leaves the minaret 4 at a pressure of the order of 1.3 bar, sufficient for it to be used for the regeneration of the adsorption bottles (not shown) serving purifying the incoming air. This is advantageous but results in a relatively high operating pressure, which is costly in terms of compression energy of the incoming air. In addition, when called upon, the rolling of air in the valve 20 corresponds to a loss of energy.

L'installation de la figure 7 reprend le principe de la figure 5 mais permet d'éviter tout laminage d'air et d'abaisser la pression de marche : la colonne 18 est transférée sous la colonne 3, dans la même virole ; elle est alimentée en tête par le liquide pauvre tombant du tronçon K1 et par un appoint de liquide pauvre LP soutiré en haut de la colonne 5 et détendu dans une vanne 21, et en cuve par la totalité de l'air détendu à 1,8 bar dans la turbine 19. Comme ce débit fournit en tête de la colonne 18 un débit d'azote impur supérieur à celui nécessaire pour le fonctionnement de la colonne 3, on peut soutirer de celle-ci un gaz résiduaire supplémentaire R, sous environ 1,6 bar, qui peut servir à la régénération des bouteilles d'adsorption précitées. Le gaz R1 sortant du minaret 4 ne sert alors plus pour cette régénération et n'a besoin que d'être à une pression légèrement supérieure à la pression atmosphérique, pour vaincre les pertes de charge de la ligne d'échange thermique servant au refroidissement de l'air entrant. La pression de marche de l'installation est ainsi abaissée.The installation of FIG. 7 takes up the principle of FIG. 5 but makes it possible to avoid any rolling of air and to lower the operating pressure: the column 18 is transferred under the column 3, in the same shell; it is supplied at the head by the lean liquid falling from the section K1 and by an addition of lean liquid LP drawn off at the top of the column 5 and expanded in a valve 21, and in the tank by all of the air expanded to 1.8 bar in the turbine 19. Since this flow rate provides an impure nitrogen flow rate at the head of the column 18 greater than that necessary for the operation of the column 3, it is possible to draw from it an additional residual gas R, under approximately 1 , 6 bar, which can be used for the regeneration of the aforementioned adsorption bottles. The gas R1 leaving the minaret 4 is no longer used for this regeneration and need only be at a pressure slightly higher than atmospheric pressure, to overcome the pressure losses of the heat exchange line used for cooling incoming air. The system operating pressure is thus lowered.

On a représenté à la figure 7 la provenance et l'utilisation des deux types de liquide riche : (a) du liquide riche avec argon, provenant d'une part de la cuve de la -colonne moyenne pression 5, d'autre part de la cuve de la colonne 18. Ces deux flux sont réunis et servent à la fois de reflux dans la colonne basse pression 6 et à l'alimentation du condenseur de tête 2A de la colonne 2, de façon classique ; et (b) du liquide riche LR1 sans argon, prélevé entre les tronçons K1 et K2 de la colonne 3 et envoyé en tête du minaret 4. Par ailleurs, en comparant cette figure 7 avec la figure 1, on constate qu'on effectue entre les tronçons K1 et K2 les deux soutirages indiqués à la figure 1, à savoir un soutirage direct de gaz résiduaire R et un soutirage de liquide LR1 qui, après mélange avec de l'azote, fournit également du gaz résiduaire R1, mais à une pression différente.FIG. 7 shows the source and the use of the two types of rich liquid: (a) rich liquid with argon, originating on the one hand from the tank of the medium pressure column 5, on the other hand from the tank of the column 18. These two flows are combined and serve both to reflux into the low pressure column 6 and to supply the head condenser 2A of the column 2, in a conventional manner; and (b) rich liquid LR1 without argon, taken between the sections K1 and K2 of column 3 and sent to the head of minaret 4. Furthermore, by comparing this FIG. 7 with FIG. 1, it can be seen that one performs between the sections K1 and K2 the two withdrawals indicated in FIG. 1, namely a direct withdrawal of waste gas R and a withdrawal of liquid LR1 which, after mixing with nitrogen, also supplies waste gas R1, but at a pressure different.

On a également représenté à la figure 7 des conduites .de soutirage d'oxygène gazeux ou liquide basse pression de la colonne 6 et d'azote gazeux ou liquide moyenne pression de la colonne 5.FIG. 7 also shows pipes for drawing off gaseous oxygen or low pressure liquid from column 6 and nitrogen gas or medium pressure liquid from column 5.

Une autre possibilité pour éviter toute perte d'énergie par laminage d'air est illustrée par l'installation de la figure 8. Dans cette installation, on retrouve la double colonne 5,6 surmontée du minaret 4 constituant le tronçon K3 de la figure 1. L'air turbiné dans la turbine 19 est détendu à 1,3 bar et insufflé dans la colonne 6. Cependant, on utilise deux colonnes auxiliaires : d'une part une colonne 3A, fonctionnant à 1,4 bar, qui réunit la colonne 14 d'épuration d'oxygène et, sous celle-ci, le tronçon K2 de la figure 1, et d'autre part une colonne 3B, fonctionnant à 1,5 bar, qui réunit le tronçon K1 de la figure 1 et, sous celui-ci, un dédoublement 6A de la partie supérieure de la colonne basse pression 6.Another possibility to avoid any loss of energy by air rolling is illustrated by the installation of FIG. 8. In this installation, there is the double column 5,6 surmounted by the minaret 4 constituting the section K3 of FIG. 1 The turbined air in the turbine 19 is expanded to 1.3 bar and blown into column 6. However, two auxiliary columns are used: on the one hand, a column 3A, operating at 1.4 bar, which joins the column 14 for purifying oxygen and, under it, the section K2 of FIG. 1, and on the other hand a column 3B, operating at 1.5 bar, which joins the section K1 of FIG. 1 and, under this one, a splitting 6A of the upper part of the low pressure column 6.

Le tronçon K2 est alimenté en tête par de l'oxygène liquide soutiré de la cuve de la colonne 6 et, en cuve, par le gaz G soutiré en-tête de la colonne 3B, c'est-à-dire en tête du tronçon K1. Du liquide riche sans argon LR1, soutiré en cuve de la colonne 3A, est envoyé en reflux à la fois en tête de la colonne 3B et du minaret 4. Du liquide pauvre est envoyé en reflux à la fois en tête de la colonne 6 et du tronçon 6A, tandis que le liquide riche avec argon provenant de la cuve de la colonne 5 est, pour partie, injecté à la fois dans la colonne 6 et dans le tronçon 6A, et, pour une autre partie, vaporisé dans le condenseur de tête 2A de la colonne 2 puis injecté en cuve du tronçon 6A. Le liquide très riche recueilli au bas de ce dernier est à son tour injecté dans la colonne 6.The section K2 is supplied at the head with liquid oxygen withdrawn from the tank of column 6 and, in the tank, by gas G withdrawn at the head of column 3B, that is to say at the head of the section K1. Rich liquid without argon LR1, withdrawn from the bottom of column 3A, is sent under reflux both at the top of column 3B and minaret 4. Poor liquid is sent under reflux both at the top of column 6 and of section 6A, while the liquid rich with argon coming from the tank of column 5 is, in part, injected both into column 6 and into section 6A, and, for another part, vaporized in the condenser of head 2A of column 2 then injected into the tank of section 6A. The very rich liquid collected at the bottom of the latter is in turn injected into column 6.

Des considérations de perte de charge montrent que l'agencement de la figure 8 est particulièrement approprié au cas où au moins la colonne 2 est équipée de garnissages. Par ailleurs, on comprend que l'installation de la figure 8 pourrait également fonctionner en remplaçant la détente d'air par une détente d'azote.Pressure drop considerations show that the arrangement of FIG. 8 is particularly suitable in the case where at least column 2 is fitted with packings. Furthermore, it is understood that the installation of FIG. 8 could also operate by replacing the air trigger with a nitrogen trigger.

La figure 9 montre une autre installation dans laquelle les tronçons K1 et K3 fonctionnent tous deux à la pression de la colonne basse pression 6 et sont confondus. Ainsi, la double colonne est surmontée d'une colonne de remélange 3B alimentée en tête par de l'oxygène liquide provenant de la cuve de la colonne 6 et en cuve par l'azote impur de tête de cette même colonne 6. Le liquide de cuve de la colonne 3B est envoyé en reflux dans la colonne 6, et de l'oxygène impur est soutiré en tête de la colonne 3B. Le gaz résiduaire R est soutiré entre les tronçons K2 d'une part, K1-K3 d'autre part.FIG. 9 shows another installation in which the sections K1 and K3 both operate at the pressure of the low pressure column 6 and are combined. Thus, the double column is surmounted by a remixing column 3B supplied at the head with liquid oxygen originating from the tank of column 6 and into the tank by the impure nitrogen at the top of this same column 6. The tank liquid from column 3B is refluxed into column 6, and impure oxygen is drawn off at the top from column 3B. The residual gas R is drawn off between the sections K2 on the one hand, K1-K3 on the other hand.

L'invention est compatible non seulement avec les installations à double colonne, mais également avec tout type d'installation de distillation d'air comprenant des moyens de production d'argon. Un exemple d'une telle installation à simple colonne est illustré à la figure 10, qui est un schéma plus complet que les figures 2 à 9.The invention is compatible not only with double column installations, but also with any type of air distillation installation comprising means for producing argon. An example of such a simple column installation is illustrated in FIG. 10, which is a more complete diagram than FIGS. 2 to 9.

Dans cette figure, l'air, comprimé et épuré, est refroidi et partiellement liquéfié dans une ligne d'échange thermique 20. La majorité du débit d'air est détendu vers 1,5 bar dans une turbine 21 (cycle Claude), puis injecté dans la simple colonne de distillation 1A reliée à la colonne 2 de production d'argon. L'air liquéfié, détendu dans une vanne 22, est injecté dans la même colonne. Celle-ci produit en cuve de l'oxygène et en tête de l'azote. Ce dernier gaz, après réchauffement dans la ligne d'échange 20, est partiellement comprimé à 6 bars par un compresseur 23, refroidi et traverse un serpentin 24 prévu en cuve de la colonne 1A, où il se condense en vaporisant l'oxygène liquide, puis est en partie détendu dans une vanne 25 et envoyé en reflux au sommet de la colonne 1A. Le reste de l'azote condensé est détendu dans une vanne 26, vaporisé dans le condenseur de tête de la colonne 2 puis envoyé en cuve de la colonne de mélange 3, réunissant les tronçons K1 et K2, qui fonctionne sous 2 à 3 bars.In this figure, the air, compressed and purified, is cooled and partially liquefied in a heat exchange line 20. The majority of the air flow is expanded to 1.5 bar in a turbine 21 (Claude cycle), then injected into the simple distillation column 1A connected to column 2 for the production of argon. The liquefied air, expanded in a valve 22, is injected into the same column. This produces oxygen in the tank and nitrogen at the top. This latter gas, after heating in the exchange line 20, is partially compressed to 6 bars by a compressor 23, cooled and passes through a coil 24 provided in the tank of column 1A, where it condenses by vaporizing the liquid oxygen, then it is partially expanded in a valve 25 and sent under reflux to the top of the column 1A. The rest of the condensed nitrogen is expanded in a valve 26, vaporized in the condenser at the head of column 2 then sent to the tank of the mixing column 3, bringing together the sections K1 and K2, which operates at 2 to 3 bars.

L'oxygène liquide produit en cuve de la colonne 1A est au moins en partie amené par pompe à la pression de la colonne 3 et injecté au sommet de celle-ci. L'oxygène impur gazeux soutiré en tête de la colonne 3 est condensé dans un second serpentin 27 en cuve de la colonne 1A, détendu dans une vanne 28 et injecté dans cette même colonne 1A.The liquid oxygen produced in the tank of column 1A is at least partly brought by pump to the pressure of column 3 and injected at the top of the latter. The impure gaseous oxygen withdrawn at the head of column 3 is condensed in a second coil 27 in the tank of column 1A, expanded in a valve 28 and injected into this same column 1A.

Le tronçon K3, situé au-dessus de la colonne 1A, est alimenté au sommet par le liquide riche LR1 soutiré entre les tronçons K1 et K2 et détendu à la basse pression, et en cuve par l'azote de tête de la colonne 1A. Ce tronçon K3 produit en cuve du liquide pauvre LP2 qui, de même que le liquide pauvre LP1 provenant de la cuve de la colonne 3, est envoyé en reflux au sommet de la colonne 1A ; il produit en tête le gaz résiduaire R1, lequel est réchauffé dans la ligne d'échange 20 avant d'être évacué ou, si la pression est suffisante, utilisé pour régénérer les bouteilles d'adsorbant servant à l'épuration de l'air entrant.The section K3, located above the column 1A, is supplied at the top by the rich liquid LR1 drawn off between the sections K1 and K2 and expanded at low pressure, and in the tank by the nitrogen at the top of the column 1A. This section K3 produces in the tank lean liquid LP2 which, like the lean liquid LP1 coming from the tank of column 3, is sent under reflux at the top of column 1A; it produces the waste gas R1 at the head, which is heated in the exchange line 20 before being evacuated or, if the pressure is sufficient, used to regenerate the bottles of adsorbent used to purify the incoming air .

Comme représenté, l'installation peut également produire de l'oxygène liquide, soutiré en cuve de la colonne 1A, de l'oxygène gazeux, également soutiré en cuve de cette colonne et réchauffé dans la ligne d'échange 20, et de l'azote gazeux, soutiré en tête de la même colonne et, après réchauffement, évacué en amont du compresseur 23. Comme indiqué en trait mixte, on peut également prélever de l'azote sous 6 bars en aval du compresseur 23.As shown, the installation can also produce liquid oxygen, drawn off from the bottom of column 1A, gaseous oxygen, also drawn off from the bottom of this column and heated in the exchange line 20, and nitrogen gas, drawn off at the top of the same column and, after heating, discharged upstream of the compressor 23. As indicated in phantom, nitrogen can also be taken at 6 bars downstream of the compressor 23.

Claims (18)

1. A process of distillation of air by means of a plant comprising a main distillation apparatus (1 ; 1,18 ; 1,6A ; 1 A) associated with an argon producing column (2) through an argon tapping conduit (10), this process comprising the following steps :
- sending to the base of a first mixing column section (K1) gaseous nitrogen which may be impure but is substantially without argon, and to the top of a second mixing column section (K2) liquid oxygen which may be impure but is substantially without argon ;
- sending to the base of the second section (K2) at least a part of the top vapour of the first section and to the top of the first section (K1) a part of the liquid produced at the base of the second section ;
- discharging from the second section (K2), at the top of the latter, impure oxygen containing at the most a few % nitrogen ;
- discharging from the first section (K1), at. the base of the latter, poor liquid (LP1) constituted by nitrogen containing at the most a few % oxygen, and sending this poor liquid as reflux in the main distillation apparatus (1 ; 1,18 ; 1,6A ; 1 A) and
- withdrawing between the two mixing column sections (K1, K2) a part of the liquid (LR1) produced at the base of the second section (K2) and effecting a remixing of this liquid with gaseous nitrogen which may be impure but is substantially without argon in a third mixing column section (K3), the top vapour of this third section constituting residual gas (R1) formed of a mixture of nitrogen and oxygen comprising about 10 to 30 % oxygen, while the liquid (LP2) produced at the base of the third section constitutes refluxing supplementary poor liquid for the main distillation apparatus (1 ; 1,18 ; 1,6A ;. 1A); this liquid being constituted by nitrogen containing at the most a few % oxygen.
2. A process according to claim 1, characterized in that said impure oxygen contains less than 15 % nitrogen.
3. A process according to one of claims 1 and 2, characterized in that between the first two sections (K1, K2) a part of the top vapour (R) is withdrawn from the first section, this withdrawal constituting a residual gas (R) formed of a mixture of nitrogen and oxygen comprising approximately 10 to 30 % oxygen.
4. A process according to any of claims 1 to 3, in which the main distillation apparatus comprises a double column (1) which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that the first and second mixing column sections (K1, K2) are operated at medium pressure by feeding the first section (K1) with nitrogen withdrawn from the medium pressure column (5) and the second section (K2) with liquid oxygen taken from the bottom of the low pressure column (6) and brought to the same pressure.
5. A process according to any of claims 1 to 4, characterized in that the impure oxygen is condensed by vaporization of liquid oxygen of the main distillation apparatus (1A), the liquid obtained being sent as reflux in this apparatus to a level above the argon tapping conduit (10).
6. A process according to any of claims 1 to 4, in which the main distillation apparatus comprises a double column (1) which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that the impure oxygen is distilled in an auxiliary low pressure column (14) fed with the liquid taken from the low pressure column (6) above the argon tapping conduit (10), the top vapour of this auxiliary low pressure column (14) being sent at roughly the same level into the low pressure column (6) while its bottom liquid is sent as reflux into the second mixing column section (K2).
7. A process according to any of claims 1 to 6, in which the main distillation apparatus comprises a double column (1) which itself comprises a medium pressure column (5) operating under a relatively high pressure, and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that a part of the top vapour of the medium pressure column (5) is expanded in a turbine (17).
8. A process according to claim 7, characterized in that the first (K1) and second (K2) mixing column sections are operated at the same pressure, which is close to the low pressure, by feeding the first section (K1) with nitrogen withdrawn from the medium pressure column and expanded in said turbine (17) and directly feeding the second section (K2) with liquid oxygen taken from the bottom of the low pressure column (6).
9. A process according to any of claims 1 to 3, in which the main distillation apparatus (1,18) comprises a double column (1) which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that the first (K1) and second (K2) mixing column sections are operated. at a recycling pressure slightly higher than the low pressure, a part of the treated air is expanded in- a turbine (19) at this recycling pressure, at least a part of the turbined air (in 18) is distilled by using poor liquid as reflux, and the first mixing column section (K1) is fed with impure nitrogen resulting from this distillation.
10. A process according to claim 9, characterized in that the excess turbined air after expansion in a valve (20) is blown into the low pressure column (6).
11. A process according to claim 9, characterized in that all of the turbined air is distilled by using as reflux the poor liquid produced at the base of the first mixing column section (K1), this latter being fed at its base by impure nitrogen resulting from this distillation and residual gas (R) being withdrawn between the two mixing column sections (K1, K2).
12. A process according to any of claims 1 to 11, characterized in that the residual gas (R, R1) is used to regenerate adsorption bottles serving for the purification of the incoming air.
13. An air distillation plant comprising :
- a main distillation apparatus (1 ; 1,18 ; 1,6A; 1A) associated with an argon producing column (2) through an argon tapping conduit (10) ;
- a first mixing column section (K1), and means for feeding the base of this section with gaseous nitrogen which may be impure but is substantially without argon ;
- a second mixing column section (K2), and means for feeding the top of this section with liquid oxygen which may be impure but is substantially without argon ;
- means for feeding the base of the second section (K2) with at least a part of the top vapour of the first section and the top of the first section (K1) with a part of the liquid produced at the base of the second section ;
- means for sending the liquid (LP1) produced at the base of the first section (K1) as reflux in the main distillation apparatus (1 ; 1,18 ; 1,6A ; 1 A) ;
- means for discharging from the second section (K2) the top vapour of the latter;
- intermediate fluid withdrawing means provided between the base of the first section (K1) and the top of the second section (K2), and
- a third mixing column section (K3), means for feeding the base of this section with gaseous - nitrogen which may be impure but is substantially without argon and its top with liquid (LR1) withdrawn through said intermediate withdrawing means, and means for withdrawing from the top of this third section a residual gas of the plant (R1).
14. A plant according to claim 13, characterized in that it comprises means for withdrawing between the base of the first section (K1) and the top of the second section (K2) vapour constituting a residual gas (R) of the plant.
15. A plant according to one of claims 13 and 14, of the type in which the main distillation apparatus (1) comprises a double column which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that it comprises an auxiliary column section (14) fed at its top with liquid withdrawn from the low pressure column (6) above the argon tapping conduit (10), means for returning the top vapour of this auxiliary section into the low pressure column roughly at the same level, the auxiliary section (14) being fed at its base with the top vapour of the second mixing column section (K2) while the bottom liquid of this auxiliary section is sent as reflux to the top of the second mixing column section.
16. A plant according to any of claims 13 to 15, of the type in which the main distillation apparatus (1) comprises a double column which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing . column (2) through said argon tapping conduit (10), characterized in that it comprises a turbine (17) for expansion of the top vapour of the medium pressure column (5).
17. A plant according to one of claims 13 to 16, of the type in which the main distillation apparatus (1,18) comprises a double column (1), which itself comprises a medium pressure column (5) operating under a relatively high pressure and a low pressure column (6) operating under a relatively low pressure and connected to the argon producing column (2) through said argon tapping conduit (10), characterized in that it comprises a turbine (19) for expanding a part of the incoming air and a second auxiliary column section (18) operating at a pressure slightly higher than the low pressure and producing at the top impure nitrogen which is fed to the base of the first mixing column section (K1).
EP86904215A 1985-07-15 1986-07-09 Process and plant for the distillation of air Expired - Lifetime EP0229803B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86904215T ATE50857T1 (en) 1985-07-15 1986-07-09 METHOD AND DEVICE FOR AIR DISTILLATION.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8510796A FR2584803B1 (en) 1985-07-15 1985-07-15 AIR DISTILLATION PROCESS AND INSTALLATION
FR8510796 1985-07-15

Publications (2)

Publication Number Publication Date
EP0229803A1 EP0229803A1 (en) 1987-07-29
EP0229803B1 true EP0229803B1 (en) 1990-03-07

Family

ID=9321294

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86904215A Expired - Lifetime EP0229803B1 (en) 1985-07-15 1986-07-09 Process and plant for the distillation of air

Country Status (17)

Country Link
US (1) US4818262A (en)
EP (1) EP0229803B1 (en)
JP (1) JPH0731004B2 (en)
KR (1) KR880700215A (en)
AU (1) AU584229B2 (en)
BR (1) BR8606791A (en)
CA (1) CA1310579C (en)
DE (1) DE3669392D1 (en)
DK (1) DK130687D0 (en)
ES (1) ES2000213A6 (en)
FI (1) FI871121A0 (en)
FR (1) FR2584803B1 (en)
IN (1) IN167585B (en)
NZ (1) NZ216821A (en)
PT (1) PT82966B (en)
WO (1) WO1987000609A1 (en)
ZA (1) ZA865185B (en)

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8620754D0 (en) * 1986-08-28 1986-10-08 Boc Group Plc Air separation
EP0286314B1 (en) * 1987-04-07 1992-05-20 The BOC Group plc Air separation
GB8806478D0 (en) * 1988-03-18 1988-04-20 Boc Group Plc Air separation
DE3913880A1 (en) * 1989-04-27 1990-10-31 Linde Ag METHOD AND DEVICE FOR DEEP TEMPERATURE DISPOSAL OF AIR
US5133790A (en) * 1991-06-24 1992-07-28 Union Carbide Industrial Gases Technology Corporation Cryogenic rectification method for producing refined argon
US5309719A (en) * 1993-02-16 1994-05-10 Air Products And Chemicals, Inc. Process to produce a krypton/xenon enriched stream from a cryogenic nitrogen generator
US5490391A (en) * 1994-08-25 1996-02-13 The Boc Group, Inc. Method and apparatus for producing oxygen
FR2778233B1 (en) * 1998-04-30 2000-06-02 Air Liquide AIR DISTILLATION SYSTEM AND CORRESPONDING COLD BOX
FR2789162B1 (en) 1999-02-01 2001-11-09 Air Liquide PROCESS FOR SEPARATING AIR BY CRYOGENIC DISTILLATION
FR2801963B1 (en) * 1999-12-02 2002-03-29 Air Liquide METHOD AND PLANT FOR AIR SEPARATION BY CRYOGENIC DISTILLATION
US6666048B1 (en) 1999-04-05 2003-12-23 L'air Liquide - Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Variable capacity fluid mixture separation apparatus and process
DE10139097A1 (en) * 2001-08-09 2003-02-20 Linde Ag Method and device for producing oxygen by low-temperature separation of air
EP1318367B2 (en) † 2001-12-04 2009-11-11 Air Products And Chemicals, Inc. Process and apparatus for the cryogenic separation of air
EP1387136A1 (en) * 2002-08-02 2004-02-04 Linde AG Process and device for producing impure oxygen by cryogenic air distillation
FR2854232A1 (en) * 2003-04-23 2004-10-29 Air Liquide Air separation procedure to produce argon uses cryogenic distillation with additional liquid flow containing 18-30 mol percent oxygen fed to low pressure column
ES2834478T3 (en) * 2012-11-02 2021-06-17 Linde Gmbh Cryogenic air separation method in air separation plant and air separation plant
DE102012021694A1 (en) * 2012-11-02 2014-05-08 Linde Aktiengesellschaft Process for the cryogenic separation of air in an air separation plant and air separation plant
CN110869687B (en) 2017-05-16 2021-11-09 特伦斯·J·埃伯特 Apparatus and process for liquefied gas
FR3074274B1 (en) * 2017-11-29 2020-01-31 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION
FR3093172B1 (en) 2019-02-25 2021-01-22 L´Air Liquide Sa Pour L’Etude Et L’Exploitation Des Procedes Georges Claude Heat and matter exchange apparatus
EP3931922B1 (en) 2019-02-25 2022-11-09 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Apparatus for exchanging heat and material
FR3110686B1 (en) * 2020-05-19 2023-06-09 Air Liquide A method of supplying oxygen and/or nitrogen as well as argon to a geographical area
US20240035743A1 (en) * 2022-08-01 2024-02-01 Air Products And Chemicals, Inc. Process and apparatus for recovery of at least nitrogen and argon

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2280383A (en) * 1939-09-08 1942-04-21 Baufre William Lane De Method and apparatus for extracting an auxiliary product of rectification
US2547177A (en) * 1948-11-02 1951-04-03 Linde Air Prod Co Process of and apparatus for separating ternary gas mixtures
IT961138B (en) * 1971-02-01 1973-12-10 Air Liquide PLANT FOR COMPRESSING A FLUID BY EXPANSION OF ANOTHER FLUID
US4137056A (en) * 1974-04-26 1979-01-30 Golovko Georgy A Process for low-temperature separation of air
US4433989A (en) * 1982-09-13 1984-02-28 Erickson Donald C Air separation with medium pressure enrichment
FR2550325A1 (en) * 1983-08-05 1985-02-08 Air Liquide METHOD AND INSTALLATION FOR AIR DISTILLATION USING A DOUBLE COLUMN
US4533375A (en) * 1983-08-12 1985-08-06 Erickson Donald C Cryogenic air separation with cold argon recycle

Also Published As

Publication number Publication date
KR880700215A (en) 1988-02-20
CA1310579C (en) 1992-11-24
DK130687A (en) 1987-03-13
AU584229B2 (en) 1989-05-18
PT82966B (en) 1992-08-31
BR8606791A (en) 1987-10-13
ZA865185B (en) 1987-03-25
FR2584803B1 (en) 1991-10-18
US4818262A (en) 1989-04-04
ES2000213A6 (en) 1988-01-16
EP0229803A1 (en) 1987-07-29
WO1987000609A1 (en) 1987-01-29
NZ216821A (en) 1988-01-08
IN167585B (en) 1990-11-17
DE3669392D1 (en) 1990-04-12
DK130687D0 (en) 1987-03-13
FI871121A (en) 1987-03-13
JPH0731004B2 (en) 1995-04-10
FR2584803A1 (en) 1987-01-16
FI871121A0 (en) 1987-03-13
PT82966A (en) 1986-08-01
AU6129086A (en) 1987-02-10
JPS63500329A (en) 1988-02-04

Similar Documents

Publication Publication Date Title
EP0229803B1 (en) Process and plant for the distillation of air
EP0689019B1 (en) Process and apparatus for producing gaseous oxygen under pressure
EP1869385B1 (en) Integrated method and installation for cryogenic adsorption and separation for producing co2
EP0628778B1 (en) Process and high pressure gas supply unit for an air constituent consuming installation
EP0937679B1 (en) Process and apparatus for the production of carbon monoxide and hydrogen
EP0547946B1 (en) Process and apparatus for the production of impure oxygen
EP0605262B1 (en) Process and apparatus for the production of gaseous oxygen under pressure
EP3625196B1 (en) Method for recovering a stream of c2+ hydrocarbons in a residual refinery gas and associated facility
EP0572590A1 (en) Method of denitrogenating a charge of a liquified hydrocarbon mixture consisting mainly of methane and containing at least 2 % mol nitrogen.
EP0937681B1 (en) Process and installation for the combined production of a ammoniac synthesis mixture and carbon monoxide
EP0379435B1 (en) Process and apparatus for the separation of air and the production of highly pure oxygen
CA3024382A1 (en) Process for cryogenic separation of a feed stream containing methane and air gases, facility for producing biomethane by purification of biogases derived from non-hazardous waste storage facilities (nhwsf) implementing the process
WO2005073651A1 (en) Cryogenic distillation method and installation for air separation
WO2010109130A1 (en) Method for processing a natural load gas for obtaining a natural processed gas and a reduction in c5+ hydrocarbons, and associated installation
EP0430803B1 (en) Process and installation for air distillation with argon production
WO2004052510A2 (en) Method for recovering blast-furnace gas and use thereof for making cast iron
EP2932177B1 (en) Method and device for separating a mixture containing carbon dioxide by means of distillation
FR2550325A1 (en) METHOD AND INSTALLATION FOR AIR DISTILLATION USING A DOUBLE COLUMN
WO1999054673A1 (en) Method and installation for air distillation with production of argon
WO2012107667A2 (en) Process and device for the cryogenic separation of a methane-rich stream
FR2837564A1 (en) Distillation of air to produce oxygen, nitrogen and pure argon, extracts oxygen of specified purity and subjects argon to catalytic de-oxygenation
EP1431691A2 (en) Process and device for the production of a Krypton/Xenon-mixture from air
WO2005047790A2 (en) Method and installation for enriching a gas stream with one of the components thereof
FR3102548A1 (en) Process and apparatus for air separation by cryogenic distillation
FR3079288A1 (en) METHOD AND APPARATUS FOR SEPARATING A SYNTHESIS GAS BY CRYOGENIC DISTILLATION

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19870203

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17Q First examination report despatched

Effective date: 19880526

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

ITF It: translation for a ep patent filed

Owner name: BARZANO' E ZANARDO MILANO S.P.A.

REF Corresponds to:

Ref document number: 50857

Country of ref document: AT

Date of ref document: 19900315

Kind code of ref document: T

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
REF Corresponds to:

Ref document number: 3669392

Country of ref document: DE

Date of ref document: 19900412

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19910610

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19910619

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19910628

Year of fee payment: 6

EPTA Lu: last paid annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19920709

Ref country code: AT

Effective date: 19920709

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19920731

Ref country code: CH

Effective date: 19920731

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

ITTA It: last paid annual fee
EAL Se: european patent in force in sweden

Ref document number: 86904215.0

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19990617

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000710

EUG Se: european patent has lapsed

Ref document number: 86904215.0

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20010619

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20010713

Year of fee payment: 16

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020731

BERE Be: lapsed

Owner name: L'*AIR LIQUIDE S.A. POUR L'ETUDE ET L'EXPLOITATION

Effective date: 20020731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20030201

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20050614

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20050615

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20050617

Year of fee payment: 20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050709

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20060708