FR2895068A1 - AIR SEPARATION METHOD BY CRYOGENIC DISTILLATION - Google Patents

AIR SEPARATION METHOD BY CRYOGENIC DISTILLATION Download PDF

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Publication number
FR2895068A1
FR2895068A1 FR0553893A FR0553893A FR2895068A1 FR 2895068 A1 FR2895068 A1 FR 2895068A1 FR 0553893 A FR0553893 A FR 0553893A FR 0553893 A FR0553893 A FR 0553893A FR 2895068 A1 FR2895068 A1 FR 2895068A1
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FR
France
Prior art keywords
oxygen
flow
air
column
compressor
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.)
Granted
Application number
FR0553893A
Other languages
French (fr)
Other versions
FR2895068B1 (en
Inventor
Cayeux Olivier De
Grenier Richard Dubettier
Alain Guillard
Bot Patrick Le
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
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
Priority to FR0553893A priority Critical patent/FR2895068B1/en
Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to BRPI0619924-0A priority patent/BRPI0619924A2/en
Priority to RU2008128818/06A priority patent/RU2387934C2/en
Priority to KR1020087014219A priority patent/KR101341278B1/en
Priority to CN2006800473992A priority patent/CN101331374B/en
Priority to PCT/FR2006/051350 priority patent/WO2007068858A2/en
Priority to UAA200808102A priority patent/UA96431C2/en
Publication of FR2895068A1 publication Critical patent/FR2895068A1/en
Application granted granted Critical
Publication of FR2895068B1 publication Critical patent/FR2895068B1/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • C01B13/0229—Purification or separation processes
    • C01B13/0248—Physical processing only
    • 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
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04048—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams
    • F25J3/04054—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams of air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
    • F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression 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
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04163—Hot end purification of the feed air
    • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
    • F25J3/04175—Hot end purification of the feed air by adsorption of the impurities at a pressure of substantially more than the highest 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
    • F25J3/0429—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
    • F25J3/04296—Claude expansion, i.e. expanded into the main or high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • 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
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • 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
    • F25J3/04466—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 for producing oxygen as a mixing column overhead gas by mixing gaseous air feed and liquid 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04812—Different modes, i.e. "runs" of operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04812—Different modes, i.e. "runs" of operation
    • F25J3/04824—Stopping of the process, e.g. defrosting or deriming; Back-up procedures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
    • F25J3/04951—Arrangements of multiple air fractionation units or multiple equipments fulfilling the same process step, e.g. multiple trains in a network
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
    • F25J3/04951—Arrangements of multiple air fractionation units or multiple equipments fulfilling the same process step, e.g. multiple trains in a network
    • F25J3/04957—Arrangements of multiple air fractionation units or multiple equipments fulfilling the same process step, e.g. multiple trains in a network and inter-connecting equipments upstream of the fractionation unit (s), i.e. at the "front-end"
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0046—Nitrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
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    • C01B2210/0051—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
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    • C01B2210/0062—Water
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0078—Noble gases
    • C01B2210/0082—Argon
    • 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
    • F25J2200/06—Processes or apparatus using separation by rectification in a dual pressure main column system in a classical double column flow-sheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/90—Details relating to column internals, e.g. structured packing, gas or liquid distribution
    • F25J2200/94—Details relating to the withdrawal point
    • 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
    • F25J2215/52—Oxygen production with multiple 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
    • 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
    • F25J2215/54—Oxygen production with multiple pressure 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/24—Multiple compressors or compressor stages in parallel
    • 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/40—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
    • F25J2240/04—Multiple expansion turbines in parallel
    • 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
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
    • F25J2240/42—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval the fluid being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/40—Processes or apparatus involving steps for recycling of process streams the recycled stream being air

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

Abstract

Selon une première marche dans un appareil de séparation d'air, on comprime dans un compresseur principal (1) de l'air destiné à la distillation, on envoie un premier débit d'air comprimé au moins dans le compresseur principal, épuré et refroidi dans une ligne d'échange (6) à la colonne moyenne pression (8) d'une double colonne, on sépare le débit d'air en des flux enrichis en azote et en oxygène dans la colonne moyenne pression, on soutire un débit d'oxygène liquide (16) de la colonne basse pression, on le pressurise jusqu'à une pression élevée et on le vaporise dans la ligne d'échange pour former un premier débit gazeux riche en oxygène et à pression élevée, on liquéfie au moins une partie (24) de l'air comprimé dans le compresseur principal et on envoie la partie liquéfiée à la double colonne et on produit également un deuxième débit gazeux riche en oxygène (115) mais à une pression moins élevée que le premier débit gazeux riche en oxygène et selon une deuxième marche, on augmente la pression de liquéfaction de l'air dans en réglant les aubages du compresseur principal (1) qui fixe cette pression, on réduit la production du deuxième débit gazeux riche en oxygène et on augmente le soutirage du premier débit gazeux riche en oxygène.According to a first step in an air separation apparatus, air is compressed in a main compressor (1) for distillation, a first compressed air flow is sent at least in the main compressor, purified and cooled. in an exchange line (6) at the medium-pressure column (8) of a double column, the air flow is separated into flows enriched in nitrogen and oxygen in the medium pressure column, a flow rate of liquid oxygen (16) of the low pressure column, pressurized to a high pressure and vaporized in the exchange line to form a first gas flow rich in oxygen and at high pressure, liquefies at least one portion (24) of the compressed air in the main compressor and the liquefied portion is sent to the double column and a second oxygen-rich gas stream (115) is also produced but at a lower pressure than the first gas-rich gas stream. oxygen and In a second step, the liquefaction pressure of the air is increased by adjusting the vanes of the main compressor (1) which sets this pressure, the production of the second oxygen-rich gas flow is reduced and the withdrawal of the first flow is increased. gas rich in oxygen.

Description

La presente invention est relative a un procede de separation d'air parThe present invention relates to a method of separating air by

distillation cryogenique, en particulier a un procede et installation de fourniture d'oxygene a deux pressions et/ou a deux puretes. Certains contextes industriels necessitent la fourniture simultanee, en grandes quantites, d'oxygene a une seule purete sous des pressions differentes, voire d'oxygene pratiquement pur et d'oxygene impur sous des pressions differentes. Par ailleurs, certaines applications industrielles necessitent des quantites importantes d'oxygene impur sous diverses pressions : gazeification du charbon, gazeification de residus petroliers, reduction-fusion directe du minerai de fer, injection de charbon dans les hauts fourneaux, metallurgie des metaux non-ferreux, etc. Une unite de production siderurgique comprend classiquement plusieurs elements ayant des besoins differents en oxygene, tel que decrit dans The Making, Shaping and Treating of Steel D, AISE, 1985. Le haut fourneau consomme de I'air enrichi en oxygene, produit en general en melangeant de I'air comprime avec de I'oxygene moyenne pression (P < 10 bar)et dans certains cas basse purete. L'oxygene basse purete a une purete d'entre 80 et 97 %. Par contre les convertisseurs et les fours a arc consomment de I'oxygene a haute pression (P> 15 bar pour injection dans convertisseur, et P > 25 bar typiquement dans les capacites tampons gaz installe en amont des convertisseurs) avec une haute purete d'entre 99 et 99,8 %. Pour fournir ces deux qualites d'oxygene, it est souvent prevu deux appareils de production d'oxygene par distillation d'air, celui qui produit I'oxygene moyenne pression etant par exemple un appareil a colonne de melange du type decrit dans US-A-4022030 et EP-A-0531182 et celui qui produit I'oxygene haute purete etant typiquement un appareil a double colonne classique. Toutes les puretes mentionnees dans ce document sont des puretes molaires.  cryogenic distillation, in particular to a method and installation for supplying oxygen at two pressures and / or two purities. Certain industrial contexts require the simultaneous supply, in large quantities, of oxygen at a single purity under different pressures, or even of practically pure oxygen and impure oxygen under different pressures. In addition, some industrial applications require large quantities of impure oxygen under various pressures: coal gasification, gasification of petroleum residues, direct reduction-melting of iron ore, coal injection in blast furnaces, metallurgy of non-ferrous metals etc. A steel production unit typically comprises several elements with different oxygen requirements, as described in The Making, Shaping and Treating Steel, AISE, 1985. The blast furnace consumes air enriched with oxygen, usually produced in mixing air compressed with medium pressure oxygen (P <10 bar) and in some cases low purity. The low purity oxygen has a purity of between 80 and 97%. On the other hand, converters and arc furnaces consume oxygen at high pressure (P> 15 bar for injection into a converter, and P> 25 bar typically in the gas buffer capacities installed upstream of the converters) with a high purity of between 99 and 99.8%. To provide these two qualities of oxygen, it is often expected two devices for producing oxygen by air distillation, that which produces the medium pressure oxygen being for example a mixing column apparatus of the type described in US-A. 4022030 and EP-A-0531182 and that which produces the high purity oxygen typically being a conventional double column apparatus. All the puretes mentioned in this document are molar puretes.

Toutes les puretes mentionnees sont des pourcentages molaires et les pressions sont des pressions absolues. La presente invention vise a resoudre le probleme suivant : parfois le client a des besoins augmentes en oxygene haute pression alors qu'il n'a plus besoin d'oxygene moyenne pression (ou n'a plus besoin d'autant d'oxygene moyenne pression / ou peut fonctionner avec une quantite reduite (voire nulle) d'oxygene moyenne pression [comme c'est le cas pour le haut fourneau]). Le but de ('invention est de satisfaire le client sans avoir recours ni a un deuxieme appareil de separation d'air, ni a la vaporisation d'oxygene liquide cryogenique venant d'un stockage. Selon un objet de ('invention, it est prevu un procede de separation d'air par distillation cryogenique dans un appareil de separation d'air comprenant un systeme de colonnes dans lequel i) selon une premiere marche a) on comprime dans un compresseur principal de ('air destine a la distillation b) on envoie un premier debit d'air comprime au moins dans le compresseur principal, epure et refroidi dans une ligne d'echange a la colonne moyenne pression d'une double colonne c) on separe le debit d'air en des flux enrichis en azote et en oxygene dans la colonne moyenne pression d) on envoie les flux enrichis en azote et en oxygene de la colonne moyenne pression a une colonne basse pression de la double colonne, directement ou indirectement e) on soutire un debit riche en azote de la colonne basse pression et on les rechauffe dans la ligne d'echange f) on soutire un debit d'oxygene liquide de la colonne basse pression, on le pressurise jusqu'a une pression elevee et on le vaporise dans la ligne d'echange pour former un premier debit gazeux riche en oxygene et a pression elevee g) on Iiquefie au moins une partie de ('air comprime dans le compresseur principal, eventuellement apres I'avoir recomprimee dans au moins un deuxieme compresseur, et on envoie la partie Iiquefiee a la double colonne et h) on produit egalement un deuxieme debit gazeux riche en oxygene mais a une pression moins elevee que le premier debit gazeux riche en oxygene ii) selon une deuxieme marche a) on augmente la pression de liquefaction de I'air dans en reglant les aubages du compresseur principal et/ou du deuxieme compresseur qui fixe(nt) cette pression b) on reduit, eventuellement a zero, la production du deuxieme 5 debit gazeux riche en oxygene c) on augmente le soutirage du premier debit gazeux riche en oxygene. Selon d'autres aspects facultatifs : - le deuxieme debit gazeux riche en oxygene est produit en soutirant un 10 debit liquide de la colonne basse pression et en le pressurisant a la pression moins elevee avant de le vaporiser dans la ligne d'echange. - le deuxieme debit gazeux riche en oxygene est produit en soutirant un debit gazeux d'une colonne de melange alimentee par de I'air ou de la colonne basse pression. 15 - le compresseur principal et eventuellement I'au moins un deuxieme compresseur comprime(nt) tout I'air destine a I'appareil. - le compresseur principal comprime tout fair destine a I'appareil et I'au moins un deuxieme compresseur ne comprime qu'une partie de I'air destine a I'appareil. 20 -lors de la deuxieme marche on augmente le debit envoye au deuxieme compresseur. - une partie de I'air comprime dans le deuxieme compresseur est detendue dans une turbine couplee au deuxieme compresseur puis envoye a la double colonne et dans lequel le debit detendu pendant la deuxieme marche 25 reduit par rapport a celui pendant la premiere marche. - lors de la deuxieme marche on maintient constant le debit envoye au deuxieme compresseur par rapport au meme debit pendant la premiere marche. - on augmente la quantite de gaz envoyee une turbine entrainant le 30 deuxieme compresseur dans la deuxieme marche par rapport a celle envoyee pendant la premiere marche. - le premier debit riche en oxygene a une purete superieure a 98.5%, et le deuxieme debit riche en oxygene a une purete inferieure a 98%. - lors de la premiere marche on soutire de la double colonne en tant que produit final un debit liquide riche en oxygene et lors de la deuxieme marche le soutirage de ce debit est reduit, eventuellement a zero. - la somme des premier et deuxieme debits riches en oxygene est substantiellement constante entre la premiere et la deuxieme marches. - pendant la premiere marche un debit d'air est detendu dans une turbine et envoye a la double colonne et pendant la deuxieme marche soit le debit detendu est rejete a ('atmosphere soit une partie du debit detendu est envoyee a la double colonne alors que le reste est rejete a ('atmosphere. - pendant la deuxieme marche on envoie de ('air comprime a la double colonne provenant d'un compresseur de secours. - une partie de ('air traite vient d'une soufflante de haut fourneau. - pendant la premiere marche on produit un debit d'azote sous pression et/ou d'argon sous pression par vaporisation de liquide pressurise et pendant la deuxieme marche on reduit ou on arrete la production de ce(s) debit(s). -pendant la premiere marche on produit un debit d'azote liquide et/ou d'argon liquide comme produit final et pendant la deuxieme marche, on reduit ou on arrete cette (ces) production(s). - les premier et deuxieme debits riche en oxygene ont la meme purete ou 20 des puretes differentes. Selon un autre aspect de ('invention, it est prevu un procede de fourniture d'un debit d'oxygene haute pression dans lequel selon une premiere marche chacune de deux installations de separation d'air fournit de I'oxygene haute pression et selon une deuxieme marche, une premiere des deux installations 25 fournit un debit d'oxygene haute pression augmente par rapport a celui selon la premiere marche et la deuxieme installation fournit un debit reduit, voire a zero ; au moins la premiere installation fonctionnant comme decrit ci-dessus et fournissant en plus de sa production initiale d'oxygene haute pression au moins 50% de la quantite d'oxygene haute pression produite pendant la 30 premiere marche par la deuxieme installation. Selon d'autres aspects de ('invention, it est prevu que : - un compresseur d'air de la deuxieme installation envoie de ('air comprime a la premiere installation pendant la deuxieme marche.  All the purities mentioned are molar percentages and the pressures are absolute pressures. The present invention aims to solve the following problem: sometimes the customer has increased needs for high pressure oxygen while he no longer needs oxygen medium pressure (or no longer needs as much oxygen medium pressure / or can operate with a reduced (or even zero) amount of medium pressure oxygen [as is the case for the blast furnace]). The object of the invention is to satisfy the customer without having recourse to either a second air separation apparatus or to the vaporization of cryogenic liquid oxygen from a storage unit according to an object of the invention. provided a method of separating air by cryogenic distillation in an air separation apparatus comprising a column system in which i) according to a first step a) is compressed in a main compressor of air for distillation b) a first compressed air flow is sent at least in the main compressor, purified and cooled in a line of exchange to the medium pressure column of a double column c) the air flow is separated into nitrogen-enriched streams and oxygen in the medium pressure column d) the flows enriched in nitrogen and oxygen are sent from the medium pressure column to a low pressure column of the double column, directly or indirectly e) a nitrogen rich flow of the column is withdrawn from the column low pressure and they are heated in the exchange line f) a liquid oxygen flow is withdrawn from the low pressure column, pressurized to a high pressure and vaporized in the exchange line to form a first flow gaseous oxygen-rich gas at high pressure g) at least a portion of compressed air is injected into the main compressor, possibly after recompression in at least a second compressor, and the liquid part is sent to the double column and h) a second oxygen-rich gaseous flow is also produced but at a lower pressure than the first gaseous flow oxygen-rich ii) in a second step a) the pressure of the air liquefaction is increased by adjusting the bladders of the main compressor and / or the second compressor which sets (s) this pressure b) is reduced, possibly to zero, the production of the second oxygen-rich gas flow c) is increased the withdrawal of the first flow of oxygen-rich gas. According to other optional aspects: the second oxygen-rich gas stream is produced by withdrawing a liquid flow from the low pressure column and pressurizing it at the lower pressure before vaporizing it in the exchange line. the second gaseous flow rich in oxygen is produced by withdrawing a gaseous flow from a mixing column fed with air or the low pressure column. The main compressor and possibly the at least one second compressor compresses all the air intended for the apparatus. the main compressor compresses everything intended for the apparatus and the at least one second compressor compresses only a part of the air intended for the apparatus. 20 -when the second step increases the flow sent to the second compressor. a part of the air compressed in the second compressor is expanded in a turbine coupled to the second compressor and then sent to the double column and in which the flow rate expended during the second step is reduced compared to that during the first step. in the second step, the flow sent to the second compressor with respect to the same flow during the first step is kept constant. the quantity of gas sent is increased by a turbine driving the second compressor in the second step relative to that sent during the first step. the first oxygen-rich flow has a purity higher than 98.5%, and the second oxygen-rich flow has a purity lower than 98%. - At the first step is withdrawn from the double column as the final product oxygen-rich liquid flow and in the second step the withdrawal of this flow is reduced, possibly zero. the sum of the first and second oxygen-rich flows is substantially constant between the first and the second steps. - during the first step, a flow of air is expelled in a turbine and sent to the double column and during the second step either the expanded flow is rejected to the atmosphere or a part of the expanded flow is sent to the double column while the remainder is discharged to the atmosphere - during the second step compressed air is sent to the double column from an emergency compressor - a portion of the air being treated comes from a blast furnace blower. during the first step, a flow of nitrogen under pressure and / or argon under pressure is produced by vaporization of pressurized liquid and during the second step the production of this flow (s) is reduced or stopped. during the first step, a flow of liquid nitrogen and / or liquid argon is produced as the final product and during the second step, this (these) production (s) is reduced or stopped. oxygen have the same purity or different purities. In the aspect of the invention, there is provided a method for supplying a high pressure oxygen flow in which in a first step each of two air separation plants supplies high pressure oxygen and in a second step. a first of the two installations 25 provides a flow of high pressure oxygen increases with respect to that in the first step and the second installation provides a reduced flow, or even zero; at least the first facility operating as described above and providing in addition to its initial production of high pressure oxygen at least 50% of the amount of high pressure oxygen produced during the first run by the second facility. According to other aspects of the invention, it is expected that: - an air compressor of the second installation sends compressed air to the first installation during the second step.

Les Figures 1, 2 et 3 representent un appareil de separation d'air capable de fonctionner selon le procede de ('invention et la Figure 4 montre un ensemble d'appareils de separation d'air dont au moins un qui fonctionne selon I'invention.  Figures 1, 2 and 3 show an air separation apparatus capable of operating according to the method of the invention and Figure 4 shows a set of air separation apparatus of which at least one operating according to the invention. .

L'installation de distillation d'air representee a la Figure 1 comprend essentiellement : un compresseur d'air 1, un appareil 2 d'epuration de ('air comprime en eau et en CO2 par adsorption, cet appareil comprenant deux bouteilles d'adsorption 2A, 2B dont rune fonctionne en adsorption pendant que I'autre est en cours de regeneration, un ensemble turbine-surpresseur 3 comprenant une turbine de detente 4, et eventuellement un surpresseur 5 dont I'arbre est couple a celui de la turbine 4, un echangeur de chaleur 6 constituant la ligne d'echange thermique de ('installation, une double colonne de distillation 7 comprenant une colonne moyenne pression 8 surmontee d'une colonne basse pression 9, avec un vaporiseur-condenseur 10 mettant la vapeur de tete (azote) de la colonne 8 en relation d'echange thermique avec le liquide de cuve (oxygene) de la colonne 9, un reservoir d'oxygene liquide 11 dont le fond est relie a une pompe d'oxygene liquide 12, et un reservoir d'azote liquide 13 dont le fond est relie a une pompe d'azote liquide 14. Cette installation est destinee a fournir, via une conduite 15, de I'oxygene gazeux sous une haute pression predeterminee, qui peut titre comprise entre quelques bars et quelques dizaines de bars (dans le present memoire, les pressions considerees sont de pressions absolues). Pour cela, de I'oxygene liquide soutire de la cuve de la colonne 9 via une conduite 16 et stocke dans le reservoir 11, est amene a la haute pression par la pompe 12 a I'etat liquide, puis vaporise et rechauffe sous cette haute pression dans des passages 17 de ('echangeur 8. La chaleur necessaire a cette vaporisation et a ce rechauffage, ainsi qu'au rechauffage et eventuellement a la vaporisation d'autres fluides soutires de la double colonne, est fournie par ('air a distiller, dans les conditions suivantes. La totalite de ('air a distiller est comprimee par le compresseur 1 a une pression superieure a la moyenne pression de la colonne 8 mais inferieure a la haute pression d'oxygene. Puis ('air, prerefroidi en 18 et refroidi au voisinage de Ia temperature ambiante en 19, est epure dans ('une, 2A par exemple, des bouteilles d'adsorption, et surpresse en totalite a la haute pression par le surpresseur 5, lequel est entrains par la turbine 4. L'air est alors introduit au bout chaud de I'echangeur 6 et refroidi en total ite jusqu'a une temperature intermediaire. A cette temperature, une fraction de I'air poursuit son refroidissement et est Iiquefie dans des passages 20 de I'echangeur, puis est detendu a la basse pression dans une vanne de detente 21 et introduit a un niveau intermediaire dans la colonne 9. Le reste de I'air, ou air excedentaire, est detendu a la moyenne pression dans la turbine 4 puis envoys directement, via une conduite 22, a la base de la colonne 8.  The air distillation plant shown in FIG. 1 essentially comprises: an air compressor 1, a device 2 for cleaning compressed air with water and adsorption CO2, this apparatus comprising two adsorption bottles 2A, 2B of which rune works in adsorption while the other is being regenerated, a turbine-booster assembly 3 comprising a detent turbine 4, and possibly a booster 5 whose shaft is coupled to that of the turbine 4, a heat exchanger 6 constituting the thermal exchange line of the installation, a double distillation column 7 comprising a medium pressure column 8 surmounted by a low pressure column 9, with a vaporizer-condenser 10 putting the head vapor ( nitrogen) of column 8 in heat exchange relationship with the bottom liquid (oxygen) of column 9, a liquid oxygen reservoir 11 whose bottom is connected to a liquid oxygen pump 12, and a reservoir of liquid nitrogen 13 whose fo Nd is connected to a liquid nitrogen pump 14. This installation is intended to supply, via a line 15, gaseous oxygen under a predetermined high pressure, which may be between a few bars and a few tens of bars (in the In this memory, the pressures considered are absolute pressures). For this, liquid oxygen withdrawn from the tank of the column 9 via a pipe 16 and stored in the tank 11, is brought to the high pressure by the pump 12 in the liquid state, then vaporizes and heats up under this high The heat required for this vaporization and reheating, as well as for the reheating and possibly the vaporization of other fluids withdrawn from the double column, is provided by the air to be distilled. under the following conditions: The entire air to be distilled is compressed by the compressor 1 at a pressure above the average pressure of column 8 but below the high oxygen pressure, then air, precooled at 18 ° C. and cooled in the vicinity of room temperature at 19, is cleaned in (1a, 2A for example, adsorption bottles, and completely overpresses the high pressure by the booster 5, which is driven by the turbine 4. L air is then introduced to the hot end of the Hanger 6 and cooled in total ite to an intermediate temperature. At this temperature, a fraction of the air continues to cool and is passed through passages in the exchanger, then is expanded at low pressure in a pressure valve 21 and fed to an intermediate level in column 9. The the remainder of the air, or excess air, is expanded at the medium pressure in the turbine 4 and then sent directly, via a pipe 22, to the base of the column 8.

On reconnait par ailleurs sur la Figure 1 les conduites habituelles des installations a double colonne, celle representee etant du type dit a minaret D, c'est-a-dire avec production d'azote sous la basse pression : les conduites 23 a 25 d'injection dans la colonne 9, a des niveaux croissants, de liquide riche (air enrichi en oxygene) detendu, de liquide pauvre inferieur (azote impur) detendu et de liquide pauvre superieur (azote pratiquement pur) detendu, respectivement, ces trois fluides etant respectivement soutires a la base, en un point intermediaire et au sommet de la colonne 8 ; et les conduites 28 de soutirage d'azote gazeux partant du sommet de la colonne 9 et 27 d'evacuation du gaz residuaire (azote impur) partant du niveau d'injection du liquide pauvre inferieur. L'azote basse pression est rechauffe dans des passages 28 de I'echangeur 6 puis evacue via une conduite 29, tandis que le gaz residuaire, apres rechauffement dans des passages 30 de I'echangeur, est utilise pour regenerer une bouteille d'adsorption, la bouteille 2B dans I'exemple considers, avant d'etre evacue via une conduite 31.  It is also recognized in Figure 1 the usual conduits for double column installations, the one shown being of the type called minaret D, that is to say with production of nitrogen under low pressure: the pipes 23 to 25 d injection into column 9, at increasing levels, of rich liquid (oxygen enriched air) expanded, lower poor liquid (impure nitrogen) expanded and upper poor liquid (substantially pure nitrogen) expanded, respectively, these three fluids being respectively withdrawn at the base, at an intermediate point and at the top of column 8; and the nitrogen gas withdrawal lines 28 from the top of the column 9 and 27 for evacuation of the waste gas (impure nitrogen) from the level of injection of the lower poor liquid. The low pressure nitrogen is heated in passages 28 of exchanger 6 and then discharged via line 29, while the waste gas, after reheating in passages of the exchanger, is used to regenerate an adsorption bottle, the bottle 2B in the example considered, before being evacuated via a pipe 31.

On voit encore sur la Figure 1 qu'une partie d'oxygene liquide 36 soutire a un niveau intermediaire de la colonne basse pression est, apres detente dans une vanne de detente 32, stockee dans le reservoir 13 et pressurise par la pompe 14 et une production d'oxygene liquide est fournie via une conduite 33 (moyenne purete) et/ou 34 (haute purete). Une partie de roxygene liquide moyenne purete est vaporise apres pressurisation dans la pompe 14 dans I'echangeur 6. La pompe 14 a une pression de sortie plus basse que la pompe 12.  FIG. 1 shows again that a portion of liquid oxygen 36 withdrawn at an intermediate level of the low pressure column is, after being expanded in a expansion valve 32, stored in the reservoir 13 and pressurized by the pump 14 and a Liquid oxygen production is provided via line 33 (medium purity) and / or 34 (high purity). Part of the medium purine liquid oxygen is vaporized after pressurization in the pump 14 in the exchanger 6. The pump 14 has a lower outlet pressure than the pump 12.

Ainsi selon la premiere marche, I'appareil produit un debit d'oxygene 15 a haute purete et haute pression ainsi qu'un debit d'oxygene 115 a moyenne purete et moyenne pression. Selon la deuxieme marche, soit la vanne 32 est fermee et on ne soutire plus d'oxygene moyenne pression soit le debit d'oxygene moyenne pression est reduit. Dans ce cas, on augmente le soutirage du debit 16 et on vaporise plus d'oxygene haute purete et haute pression provenant de la pompe 12 dans I'echangeur 6. Afin de vaporiser ce debit augmente, on augmente la pression de sortie du compresseur 1 ainsi que le debit d'air comprime en reglant les aubages du compresseur 1. S'il n'y pas de production d'oxygene liquide, la somme des debits 16 et 36 est constante, entre les premiere et deuxieme marches car le debit d'air comprime dans le compresseur 1 reste substantiellement constant entre les deux marches. S'il y a production d'oxygene liquide, soit la somme des debits 16 et 36 est constante, entre les premiere et deuxieme marches, soit on peut produire une somme plus grande pendant la deuxieme marche en reduisant voire en supprimant la production d'oxygene liquide. Si la production de liquide est reduite, une partie de ('air provenant de la turbine Claude 4 sera envoye a ('atmosphere apres titre melange au gaz residuaire 27.  Thus, according to the first step, the apparatus produces a high purity, high pressure oxygen stream as well as medium purity and medium pressure oxygen flow. According to the second step, the valve 32 is closed and no more medium pressure oxygen is withdrawn or the average pressure oxygen flow is reduced. In this case, the withdrawal of the flow 16 is increased and more high purity and high pressure oxygen is pumped from the pump 12 into the exchanger 6. In order to vaporize this flow rate, the outlet pressure of the compressor 1 is increased. as well as the air flow compresses by regulating the blades of the compressor 1. If there is no production of liquid oxygen, the sum of the flows 16 and 36 is constant, between the first and second steps because the flow of Compressed air in the compressor 1 remains substantially constant between the two steps. If liquid oxygen is produced, the sum of the flows 16 and 36 is constant, between the first and second steps, or a larger sum can be produced during the second step by reducing or even suppressing the production of liquid oxygen. If the production of liquid is reduced, a part of the air coming from the Claude 4 turbine will be sent to the atmosphere after mixing with the waste gas 27.

L'installation representee a la Figure 2 est destinee a produire de I'oxygene gazeux a deux pressions et a deux puretes. Elie comprend essentiellement une double colonne de distillation 41, une ligne d'echange thermique principale 42, un sous-refroidisseur 43, un compresseur d'air unique 44, une soufflante 45 de surpression d'air, une turbine de detente 46 dont la roue est montee sur le meme arbre que celle du surpresseur 45, une soufflante additionnelle 47 entrainee par un moteur electrique 48, et une pompe d'oxygene liquide 49. La double colonne est constituee, de maniere classique, d'une colonne moyenne pression 50 fonctionnant sous environ 6 bars et surmontee d'une colonne basse pression 51 fonctionnant Iegerement au- dessus de la pression atmospherique avec, en cuve de cette derniere, un vaporiseur-condenseur 52 qui met en relation d'echange thermique I'oxygene liquide de cuve de la colonne basse pression avec I'azote de tete de la colonne moyenne pression.  The plant shown in Figure 2 is intended to produce oxygen gas at two pressures and two purities. Elie essentially comprises a double distillation column 41, a main heat exchanger line 42, a subcooler 43, a single air compressor 44, a blower 45 of air overpressure, a blast turbine 46 whose wheel is mounted on the same shaft as that of the booster 45, an additional fan 47 driven by an electric motor 48, and a liquid oxygen pump 49. The double column is constituted, in a conventional manner, a medium pressure column 50 operating at about 6 bar and surmounted by a low pressure column 51 operating slightly above the atmospheric pressure with, in the tank of the latter, a vaporizer-condenser 52 which puts in heat exchange relation the liquid oxygen of the tank of the low pressure column with the nitrogen of the head of the medium pressure column.

En fonctionnement pendant la premiere marche, le compresseur d'air 44 de I'installation comprime directement la totalite de I'air a la premiere haute pression de I'ordre de 23 bars, et un premier courant de cet air est traite comme precedemment dans les passages 53, la turbine 46 et la vanne de detente 54 puis envoys a la base de la colonne 50. En revanche, le reste de cet air est surpresse en deux stapes, par deux soufflantes montees en serie : une premiere soufflante 70 qui est couplee directement a la turbine 46, et une deuxieme soufflante 71 directement couplee a une deuxieme turbine de detente 72. L'air surpresse en 70 passe en totalite dans la soufflante 71 puis dans les passages 56 de la ligne d'echange 42, et une partie de cet air est sorti de la ligne d'echange a une temperature T2 superieure a la temperature T1 pour titre detendu dans la turbine 72. L'echappement de cette derniere, a la moyenne pression, est relie a la base de la colonne 50 comme celui de la turbine 46. L'air a la plus haute pression non detendu dans la turbine 72 poursuit son refroidissement et est Iiquefie dans les passages 56 jusqu'au bout froid de la ligne d'echange, puis est detendu dans des vannes de detente 57 et 57A et reparti entre les deux colonnes 50 et 51. On entend ici par surpresseur ou soufflante un compresseur a une seule roue dont la depense d'energie, de par le debit de gaz traite et le taux de compression, est considerablement inferieure a celle du compresseur principal 44 de I'installation, et par exemple de I'ordre de 2 a 3 % de cette derniere. Le taux de compression d'une telle soufflante est generalement inferieur a 2. Chacune des soufflantes dont it est question ici comporte a sa sortie un refrigerant a eau ou a air atmospherique non represents.  In operation during the first step, the air compressor 44 of the plant directly compresses all the air at the first high pressure of the order of 23 bars, and a first stream of this air is treated as previously in the passages 53, the turbine 46 and the expansion valve 54 and sent to the base of the column 50. On the other hand, the rest of this air is overpressed in two stages, by two blowers mounted in series: a first blower 70 which is coupled directly to the turbine 46, and a second fan 71 directly coupled to a second expansion turbine 72. The air pressure 70 passes entirely in the fan 71 and in the passages 56 of the exchange line 42, and a part of this air has left the line of exchange at a temperature T2 greater than the temperature T1 for the title relaxed in the turbine 72. The exhaust of the latter, at the average pressure, is connected to the base of the column 50 like that of the turbine 46. The air At the highest unpressurized pressure in the turbine 72 the cooling continues and is passed through the passages 56 to the cold end of the exchange line, then is expanded in expansion valves 57 and 57A and distributed between the two columns. 50 and 51. Here is meant by blower or blower a compressor with a single wheel whose energy expenditure, by the gas flow treated and the compression ratio, is considerably lower than that of the main compressor 44 of the installation , and for example of the order of 2 to 3% of the latter. The compression ratio of such a blower is generally less than 2. Each of the blowers referred to herein has at its output an unrepresented water or air air cooler.

L'oxygene liquide soutire en cuve de la colonne 51 est amens par la pompe 49 a la haute pression, puis vaporise et rechauffe dans des passages 58 de la ligne d'echange avant d'etre evacue de I'installation via une conduite de production 59 comme debit d'oxygene gazeux haute pression et haute purete.  The liquid oxygen withdrawn from the column 51 is fed by the pump 49 at high pressure, then vaporizes and reheats in passages 58 of the exchange line before being evacuated from the installation via a production line. 59 as a flow of gaseous oxygen high pressure and high purity.

L'oxygene liquide soutire a un niveau intermediaire de la colonne 51 est amens par la pompe 70 a la moyenne pression, puis vaporise et rechauffe dans des passages 58 de la ligne d'echange avant d'etre evacue de I'installation via une conduite de production 59 comme debit d'oxygene gazeux moyenne pression et moyenne purete.  The liquid oxygen withdrawn at an intermediate level of the column 51 is fed by the pump 70 at medium pressure, then vaporizes and reheats in passages 58 of the exchange line before being evacuated from the installation via a pipe. of production 59 as flow of gaseous oxygen medium pressure and average purity.

On retrouve par ailleurs dans ('installation de la Figure 2 les conduites et accessoires habituels des installations a double colonne : une conduite 60 de remontee dans la colonne 51 du liquide riche (air enrichi en oxygene) recueilli en cuve de la colonne 50, avec sa vanne de detente 61, une conduite 62 de remontee en tete de la colonne 51 du liquide pauvre (azote a peu pret pur) soutire en tete de la colonne 50, avec sa vanne de detente 83, ainsi qu'une conduite 64 de production d'oxygene liquide, piquee en cuve de la colonne 51, qu'une conduite 65 de production d'azote liquide, piquee sur la conduite 62, et qu'une conduite 66 de soutirage d'azote impur, constituant le gaz residuaire de ('installation, piquee en tete de la colonne 51, cet azote impur etant rechauffe dans le sous-refroidisseur 43 puis dans des passages 67 de la ligne d'echange avant d'etre evacue via une conduite 68. Selon la deuxieme marche, soit on ne soutire plus d'oxygene moyenne pression soit le debit d'oxygene moyenne pression est reduit. Dans ce cas, on augmente le soutirage du debit d'oxygene liquide en cuve de la colonne basse pression et on vaporise plus d'oxygene haute purete et haute pression provenant de la pompe 49 dans I'echangeur 6. Afin de vaporiser ce debit augmente, on augmente la pression de sortie du compresseur 1 ainsi que le debit d'air comprime en reglant les aubages du compresseur 1. Alternativement ou additionnellement, on regle le debit d'air au moyen des soufflantes 70, 71. S'il n'y a pas de production d'oxygene liquide et le debit d'air comprime dans le compresseur 44 reste substantiellement constant entre les deux marches la somme des debits 59 et 72 est constante, entre les premiere et deuxieme marches. Par contre si le debit comprime augmente pendant la deuxieme marche, la somme des produits oxygenes gazeux peut augmenter. La reduction voire la suppression de la production d'oxygene liquide permet egalement plus de variation dans les productions gazeuses. Si la production de liquide est reduite, au moins une partie de ('air provenant d'au moins une des turbines 46,72 sera envoyee a ('atmosphere apres titre melangee au gaz residuaire 66 pendant la deuxieme marche.  In the installation of FIG. 2, the usual conduits and accessories of the double-column installations are also found: a pipe 60 for raising in the column 51 of the rich liquid (oxygen-enriched air) collected in the tank of the column 50, with its expansion valve 61, a pipe 62 for raising the head of the column 51 of the lean liquid (nitrogen has a low purity) withdrawn at the head of the column 50, with its expansion valve 83, and a pipe 64 production liquid oxygen, quenched in the tank of the column 51, a line 65 for producing liquid nitrogen, spotted on the pipe 62, and that a conduit 66 for withdrawing impure nitrogen, constituting the waste gas of installation, pique head of the column 51, the impure nitrogen is heated in the subcooler 43 and in passages 67 of the exchange line before being evacuated via a pipe 68. According to the second step, or does not withdraw more oxygen medium pressure is the flow of o xygene medium pressure is reduced. In this case, the withdrawal of the flow of liquid oxygen in the bottom of the low pressure column is increased and more high purity and high pressure oxygen is pumped from the pump 49 into the exchanger 6. In order to vaporize this flow increases the output pressure of the compressor 1 and the compressed air flow are increased by adjusting the blades of the compressor 1. Alternatively or additionally, the air flow is regulated by means of the blowers 70, 71. there is no production of liquid oxygen and the air flow compressed in the compressor 44 remains substantially constant between the two steps the sum of the flows 59 and 72 is constant, between the first and second steps. On the other hand, if the compressed flow increases during the second step, the sum of the gaseous oxygen products can increase. The reduction or even the suppression of the production of liquid oxygen also allows more variation in gaseous productions. If the liquid production is reduced, at least a portion of the air from at least one of the turbines 46, 72 will be sent to the mixed-waste atmosphere during the second step.

Dans la Figure 3, un debit d'air a la pression atmospherique est comprime a environ 15 bars dans un compresseur principal 1. L'air est ensuite eventuellement refroidi, avant d'etre epure pour enlever les impuretes (non- illustre). L'air epure est divise en deux. Une partie de I'air 3 est envoyee a un surpresseur 5 ou elle est comprimee jusqu'a une pression d'entre 17 et 20 bars et ensuite I'air surpresse est refroidi par un refrigerant a I'eau 7 avant d'etre envoye au bout chaud de la ligne d'echange principal 9 de I'appareil de separation d'air. L'air surpresse 11 se refroidit jusqu'a une temperature intermediaire avant de sortir de la ligne d'echange et d'etre divise en deux fractions. II est evidemment possible qu'une fraction du debit 11 poursuive son refroidissement jusqu'au bout froid de la ligne d'echange 9 d'ou it sortira liquefie. Une fraction 13 est envoyee dans une turbine 17 et le reste, une fraction 15 est envoyee dans une turbine 19. Les deux turbines ont la meme temperature et pression d'aspiration et la meme temperature et pression de sortie mais it est evidemment possible que ces temperatures et pression soient proches les unes des autres au lieu d'etre identiques. Les deux debits turbines sont melanges pour former un debit 21 d'air dont une partie 121 est envoyee vers la double colonne et le reste 122 vers la colonne de melange 300. Le debit 122 constitue une partie du debit 21 ou eventuellement une fraction de la partie gazeuse du debit 21 dans le cas ou celui-ci serait diphasique. II est evidemment possible d'envoyer tout le debit 21 a la colonne moyenne pression 100 et d'en sortir une partie gazeuse 122 pour envoi a la colonne de melange, la colonne moyenne pression remplagant dans ce cas, le separateur de phases. Les pressions de la colonne moyenne pression et de la colonne de melange peuvent titre differentes. En variante, la turbine 19 peut titre une turbine d'insufflation debouchant a la pression de la colonne basse pression. Une autre partie 2 de I'air a 15 bars constituant le reste de fair est refroidie dans la ligne d'echange a une temperature intermediaire superieure a la temperature d'aspiration des turbines 17, 19, comprimee dans un deuxieme surpresseur 23 jusqu'a 30 bars environ et reintroduite dans la ligne d'echange 9 a une temperature plus elevee afin de poursuivre son refroidissement. Ainsi, I'air 37 a 30 bars environ se liquefie dans la ligne d'echange et de I'oxygene liquide 25 se vaporise dans la ligne d'echange, la temperature de vaporisation du liquide etant proche de la temperature d'aspiration du deuxieme surpresseur 23. L'air liquefie sort de la ligne d'echange et est envoye vers le systeme de colonnes.  In Figure 3, an air flow at atmospheric pressure is compressed to about 15 bar in a main compressor 1. The air is then optionally cooled, before being purified to remove impurities (not shown). The pure air is divided in two. Part of the air 3 is sent to a booster where it is compressed to a pressure of between 17 and 20 bar and then the booster air is cooled by a water cooler 7 before being sent. at the hot end of the main exchange line 9 of the air separation apparatus. The excess air 11 cools to an intermediate temperature before exiting the line of exchange and being divided into two fractions. It is obviously possible for a fraction of the flow 11 to continue to cool down to the cold end of the exchange line 9 from which it will leave the liquefy. A fraction 13 is sent into a turbine 17 and the remainder, a fraction 15 is sent into a turbine 19. The two turbines have the same temperature and suction pressure and the same temperature and outlet pressure but it is obviously possible that these temperatures and pressure are close to each other instead of being identical. The two flow turbines are mixed to form an air flow 21 of which a portion 121 is sent to the double column and the remainder 122 to the mixing column 300. The flow 122 constitutes a part of the flow 21 or possibly a fraction of the gas part of the flow 21 in the case where it would be two-phase. It is obviously possible to send all the flow 21 to the medium pressure column 100 and to leave a gas portion 122 for sending to the mixing column, the medium pressure column replacing in this case the phase separator. The pressures of the medium pressure column and the mixing column may be different. In a variant, the turbine 19 may be used as an insufflation turbine which discharges at the pressure of the low pressure column. Another part 2 of the air at 15 bars constituting the remainder of the water is cooled in the line of exchange at an intermediate temperature higher than the suction temperature of the turbines 17, 19, compressed in a second booster 23 up to 30.degree. Approximately 30 bars and reintroduced in the exchange line 9 at a higher temperature in order to continue cooling. Thus, the air 37 to 30 bar approximately is liquefied in the exchange line and the liquid oxygen 25 vaporizes in the exchange line, the vaporization temperature of the liquid being close to the suction temperature of the second blower 23. The air liquefies out of the line of exchange and is sent to the system of columns.

Le premier surpresseur 5 est couple avec rune des turbines 17, 19 et le deuxieme surpresseur 23 est couple avec I'autre des turbines 19, 17. Le systeme de colonnes d'un appareil de separation d'air est constitue par une colonne moyenne pression 100 thermiquement reliee avec une colonne basse pression 200 a minaret, une colonne de melange 300 et une colonne argon optionnelle (non-illustree). La colonne basse pression ne comporte pas obligatoirement de minaret. La colonne moyenne pression opere a une pression de 5,5 bars mais peut operer a une pression plus elevee.  The first booster 5 is coupled with one of the turbines 17, 19 and the second booster 23 is coupled with the other of the turbines 19, 17. The column system of an air separation apparatus is constituted by a medium pressure column. 100 thermally connected with a low pressure column 200 minaret, a mixing column 300 and an optional argon column (non-illustrated). The low pressure column does not necessarily have a minaret. The medium pressure column operates at a pressure of 5.5 bar but can operate at a higher pressure.

L'air 121 provenant des deux turbines 17, 19 est le debit envoye en cuve de la colonne moyenne pression 100. L'air liquefie 37 est detendu dans la vanne 39 ou eventuellement dans une turbine et envoye au systeme de colonnes. Du liquide riche 51, du liquide pauvre inferieur 53 et du liquide pauvre superieur 55 sont envoyes depuis la colonne moyenne pression 100 vers la colonne basse pression 200 apres des etapes de detente dans des vannes et de sous-refroidissement. II sera maintenant decrit ('operation de ('appareil selon une premiere marche.  The air 121 from the two turbines 17, 19 is the flow sent to the tank of the medium pressure column 100. The air 37 is expanded in the valve 39 or possibly in a turbine and sent to the column system. Rich liquid 51, lower lean liquid 53 and higher lean liquid 55 are sent from the medium pressure column 100 to the low pressure column 200 after valve expansion and subcooling steps. It will now be described the operation of the apparatus according to a first step.

De I'oxygene liquide est pressurise par la pompe 500 et envoye comme liquide pressurise 25 vers la ligne d'echange 9. Une partie du liquide 501 peut titre stocke pour servir de produit liquide. D'autres liquides, pressurises ou non, peuvent se vaporiser dans la ligne d'echange. De I'azote gazeux est optionnellement soutire de la colonne moyenne 25 pression et se refroidit egalement dans la ligne d'echange 9. De I'azote 33 est soutire en tete de la colonne basse pression et se rechauffe dans la ligne d'echange, apres avoir servi a sous-refroidir les liquides de reflux. De I'azote residuaire 27 est soutire d'un niveau inferieur de la colonne 30 basse pression et se rechauffe dans la ligne d'echange 9, apres avoir servi a sous-refroidir les liquides de reflux. La colonne peut eventuellement produire de ('argon en traitant un debit 51 soutire en colonne basse pression 200. Le debit 52 est le liquide de cuve renvoye de la colonne argon, s'il y en a une.  Liquid oxygen is pressurized by the pump 500 and sent as a pressurized liquid to the exchange line 9. Part of the liquid 501 can be stored as a liquid product. Other liquids, pressurized or not, can vaporize in the line of exchange. Nitrogen gas is optionally withdrawn from the medium pressure column and is also cooled in the exchange line 9. Nitrogen 33 is withdrawn at the head of the low pressure column and heats up in the exchange line, after serving to sub-cool the reflux liquids. Residual nitrogen 27 is withdrawn from a lower level of the low pressure column and warms up in the exchange line 9, after having served to sub-cool the reflux liquids. The column may optionally produce argon by treating a depressed flow 51 in the low pressure column 200. The flow 52 is the returned vessel liquid from the argon column, if any.

La colonne de melange 300 est alimentee en tete par un liquide 35 riche en oxygene soutire a un niveau intermediaire de la colonne basse pression 200 pressurise par la pompe 600 et en cuve par un debit d'air gazeux 122 provenant des turbines 17, 19. La colonne de melange opere essentiellement a la moyenne pression. Un debit d'oxygene gazeux 137 est soutire en tete de la colonne de melange et se rechauffe ensuite dans la ligne d'echange 9 et un debit liquide 41 est soutire en cuve et envoye a la colonne basse pression apres detente dans une vanne. II est possible de soutirer un debit intermediaire de la colonne 300 qui est envoye a la colonne basse pression. La deuxieme marche differe de la premiere en ce que la production d'oxygene de la colonne de melange est reduite voire supprimee. Dans ce cas, on augmente le soutirage du debit d'oxygene liquide 35 en cuve de la colonne basse pression et on vaporise plus d'oxygene haute purete et haute pression provenant de la pompe 600 dans I'echangeur 9 pour former le debit 125. Afin de vaporiser ce debit augmente, on augmente la pression de sortie du compresseur 1 ainsi que le debit d'air comprime en reglant les aubages du compresseur 1. Alternativement ou additionnellement, on regle le debit d'air et sa pression au moyen du surpresseur froid 23. Ainsi la pression de I'air 37 peut titre modifiee pour la deuxieme marche en modifiant les aubages du compresseur 1 et/ou ceux du surpresseur froid 23. Selon la variante de la deuxieme marche ou la colonne de melange ne produit pas d'oxygene, on n'envoie plus d'air 122 en cuve de la colonne de melange. Celle-ci n'est plus alimentee non plus en oxygene liquide et son fonctionnement est arrete. Le surplus de I'air est envoye a la double colonne. Le surpresseur 23 comprime I'air 2 a une pression plus elevee, ce qui permet de vaporiser plus d'oxygene liquide en augmentant le soutirage en cuve de la colonne basse pression pour pressuriser un debit plus grand dans la pompe 500. Le seul gaz riche en oxygene produit est de I'oxygene moyenne pression et moyenne purete. Selon une autre variante de la deuxieme marche on envoie moins d'air 122 en cuve de la colonne de melange. Celle-ci regoit moins d'oxygene liquide 35 et son fonctionnement est reduit. Le surplus de I'air est envoye a la double colonne.  The mixing column 300 is fed at the top by an oxygen rich liquid withdrawn at an intermediate level of the low pressure column 200 pressurized by the pump 600 and in the tank by a flow of gaseous air 122 from the turbines 17, 19. The mixing column operates essentially at medium pressure. A flow of gaseous oxygen 137 is withdrawn at the head of the mixing column and is then heated in the exchange line 9 and a liquid flow 41 is withdrawn in the tank and sent to the low pressure column after expansion in a valve. It is possible to withdraw an intermediate flow from the column 300 which is sent to the low pressure column. The second step differs from the first in that the oxygen production of the mixing column is reduced or suppressed. In this case, the withdrawal of the liquid oxygen flow 35 into the bottom of the low pressure column is increased and more high purity, high pressure oxygen is pumped from the pump 600 into the exchanger 9 to form the flow 125. In order to vaporize this increased flow rate, the outlet pressure of the compressor 1 and the compressed air flow are increased by regulating the blades of the compressor 1. Alternatively or additionally, the air flow and its pressure are regulated by means of the booster 23. Thus the air pressure 37 may be modified for the second step by changing the blades of the compressor 1 and / or those of the cold booster 23. According to the variant of the second step or the mixing column does not produce oxygen, it no longer sends air 122 in the tank of the mixing column. It is no longer supplied with liquid oxygen and its operation is stopped. The surplus of the air is sent to the double column. The booster 23 compresses the air 2 at a higher pressure, which allows more liquid oxygen to be vaporized by increasing the tank withdrawal from the low pressure column to pressurize a larger flow in the pump 500. The only rich gas Oxygen product is oxygen medium pressure and medium purity. According to another variant of the second step, less air 122 is sent to the bottom of the mixing column. It receives less liquid oxygen and its operation is reduced. The surplus of the air is sent to the double column.

Le surpresseur 23 comprime I'air 2 a une pression plus elevee, ce qui permet de vaporiser plus d'oxygene liquide en augmentant le soutirage en cuve de la colonne basse pression pour pressuriser un debit plus grand dans la pompe 500.  The booster 23 compresses the air 2 at a higher pressure, which makes it possible to vaporize more liquid oxygen by increasing the tank withdrawal from the low pressure column to pressurize a larger flow rate in the pump 500.

L'appareil produit plus d'oxygene moyenne pression et moyenne purete 25 qu'avec la premiere marche mais continue a produire une quantite reduite d'oxygene basse purete et basse pression 137. S'il n'y a pas de production d'oxygene liquide 501 et le debit d'air comprime dans le compresseur 1 reste substantiellement constant entre les deux marches la somme des debits 125 et 137 est constante, entre les premiere et deuxieme marches. Par contre si le debit comprime augmente pendant la deuxieme marche, la somme des produits oxygenes gazeux peut augmenter. La reduction voire la suppression de la production d'oxygene liquide 501 permet egalement plus de variation dans la productions gazeuses. Si la production de liquide est reduite, au moins une partie de ('air provenant d'au moins une des turbines 17,19 sera envoyee a ('atmosphere apres titre melangee au gaz residuaire 27 pendant la deuxieme marche. Pendant la deuxieme marche, it est souhaitable de varier le rapport des quantites d'air envoyees aux turbines 17,19, de sorte que si le debit surpresse dans le surpresseur 23 augmente, la turbine 19 entrainant ce surpresseur regoit un pourcentage augmente de ('air provenant du surpresseur froid 23 et la turbine 17, evidemment une pourcentage reduit. Ici le surpresseur est entraine par une turbine d'air mais it sera aisement compris que le surpresseur pourraittitre entraine par une turbine d'azote, une turbine a vapeur ou une autre turbine presente sur le site. L'invention permet en particulier de resoudre le probleme pose quand deux appareils de separation d'air sont produisent de I'oxygene haute pression. Si run des appareils n'en produit plus ou en produit moins, I'autre peut augmenter la production d'oxygene haute pression au prix de la production d'oxygene moyenne pression en fonctionnant selon ('invention. Eventuellement ('air additionnel requis peut titre amene a I'autre appareil a partir d'un compresseur d'air ou d'un surpresseur d'air de I'appareil en arret ou marche reduite. En particulier ('invention permet a I'autre appareil permet de fournir jusqu'a 50% du produit provenant precedemment de I'appareil en arret ou marche reduite. II est evidemment possible de produire les deux pressions d'oxygene pendant la premiere et eventuellement la deuxieme marche en pompant un debit unique d'oxygene dans une pompe et en detendant une partie. Dans ce cas, les debits auront evidemment la meme purete. L'appareil peut egalement produire de I'azote et/ou d'argon sous pression par vaporisation d'azote et d'argon pompe(s). II est egalement envisageable de baisser ou arreter les productions d'azote et/ou argon sous pression pendant la deuxieme marche par rapport a la production pendant la premiere marche. L'appareil peut egalement produire de I'azote liquide comme produit final pendant la premiere marche. Dans ce cas, it est envisageable de reduire ou d'arreter la production de liquide pendant la deuxieme marche.  The apparatus produces more medium pressure and medium purge oxygen than with the first step, but continues to produce a reduced amount of low purity and low pressure oxygen 137. If there is no oxygen production liquid 501 and the air flow compressed in the compressor 1 remains substantially constant between the two steps the sum of the flows 125 and 137 is constant, between the first and second steps. On the other hand, if the compressed flow increases during the second step, the sum of the gaseous oxygen products can increase. The reduction or even the suppression of the production of liquid oxygen 501 also allows more variation in the gaseous productions. If the liquid production is reduced, at least part of the air coming from at least one of the turbines 17, 19 will be sent to the mixed-gas atmosphere during the second step, during the second step. It is desirable to vary the ratio of the quantities of air sent to the turbines 17, 19, so that if the overpressure flow in the booster 23 increases, the turbine 19 causing this booster receives an increased percentage of air from the cold booster. 23 and the turbine 17, obviously a reduced percentage.Here the booster is driven by an air turbine but it will be easily understood that the booster cantititre driven by a nitrogen turbine, a steam turbine or other turbine present on the In particular, the invention makes it possible to solve the problem posed when two air-separation apparatuses produce high-pressure oxygen.If some apparatus produces no more or produces less, the other can to increase the production of high pressure oxygen at the cost of the production of medium pressure oxygen by operating according to the invention. Optionally, additional air required may be supplied to the other apparatus from an air compressor or an air booster of the apparatus at a standstill or reduced operation. Another apparatus can supply up to 50% of the product previously obtained from the apparatus on standby or reduced operation It is of course possible to produce the two oxygen pressures during the first and possibly the second step by pumping a single flow of In this case, the flow rates will obviously have the same purity.The apparatus can also produce nitrogen and / or argon under pressure by nitrogen and argon spraying. pump (s) It is also possible to reduce or stop the production of nitrogen and / or argon under pressure during the second step compared to the production during the first step.The apparatus can also produce liquid nitrogen as final product during the first wed che. In this case, it is possible to reduce or stop the production of liquid during the second step.

La Figure 4 montre deux appareils de separation d'air ASU 1 et ASU 2, dont au moins le premier ASU 1 fonctionne selon I'invention. Les deux appareils sont alimentes en air par leurs compresseurs respectifs C1,C2. Si I'appareil ASU 2 reduit sa production d'oxygene haute purete 15, I'ASU 1 commence a fonctionner selon la deuxieme marche pour produire plus d'oxygene haute pression 15. Pour assister, de I'air epure ou non epure peut titre envoye du compresseur C2 a I'appareil ASU 1.25  Figure 4 shows two air separation units ASU 1 and ASU 2, of which at least the first ASU 1 operates according to the invention. Both devices are supplied with air by their respective compressors C1, C2. If the ASU 2 reduces its production of high purity oxygen 15, the ASU 1 starts to operate according to the second step to produce more high pressure oxygen 15. To assist, pure or unpurified air can be used. sent from compressor C2 to ASU 1.25

Claims (20)

REVENDICATIONS 1. Procede de separation d'air par distillation cryogenique dans un appareil de separation d'air comprenant un systeme de colonnes dans lequel i) selon une premiere marche a) on comprime dans un compresseur principal (1, 44) de I'air destine a Ia distillation b) on envoie un premier debit d'air comprime au moins dans le compresseur principal, epure et refroidi dans une ligne d'echange (6, 42, 9) a la colonne moyenne pression (8, 50, 100) d'une double colonne c) on separe le debit d'air en des flux enrichis en azote et en oxygene dans la colonne moyenne pression d) on envoie les flux enrichis en azote et en oxygene de la colonne moyenne pression a une colonne basse pression (9, 51, 200) de la double colonne, directement ou indirectement e) on soutire un debit riche en azote de la colonne basse pression et on les rechauffe dans la ligne d'echange f) on soutire un debit d'oxygene liquide de la colonne basse pression, on le pressurise jusqu'a une pression elevee et on le vaporise dans la ligne d'echange pour former un premier debit gazeux riche en oxygene (15, 59, 125) et a pression elevee g) on Iiquefie au moins une partie de I'air comprime dans le compresseur principal, eventuellement apres I'avoir recomprimee dans au moins un deuxieme compresseur, et on envoie la partie Iiquefiee a la double colonne et h) on produit egalement un deuxieme debit gazeux riche en oxygene (115, 72, 137) mais a une pression moins elevee que le premier debit gazeux riche en oxygene ii) selon une deuxieme marche a) on augmente la pression de liquefaction de I'air dans en reglant les aubages du compresseur principal et/ou du deuxieme compresseur qui fixe(nt) cette pression b) on reduit, eventuellement a zero, la production du deuxieme debit gazeux riche en oxygenec) on augmente le soutirage du premier debit gazeux riche en oxygene.  A method of separating air by cryogenic distillation in an air separation apparatus comprising a column system in which i) according to a first step a) is compressed in a main compressor (1, 44) of air intended at distillation b) a first compressed air flow is sent at least in the main compressor, purified and cooled in a line of exchange (6, 42, 9) to the medium pressure column (8, 50, 100) d a double column c) the air flow is separated into flows enriched in nitrogen and oxygen in the medium pressure column d) the nitrogen and oxygen enriched streams are sent from the medium pressure column to a low pressure column ( 9, 51, 200) of the double column, directly or indirectly e) a nitrogen-rich flow of the low pressure column is withdrawn and heated in the exchange line f) a flow of liquid oxygen is withdrawn from the reactor. low pressure column, it is pressurized to a high pressure and vaporized in the In order to form a first gaseous flow rich in oxygen (15, 59, 125) and at a high pressure g) at least a portion of the compressed air is imaged in the main compressor, possibly after having recompressed it in minus one second compressor, and the double column is sent to the double column and h) a second oxygen-rich gas stream (115, 72, 137) is produced, but at a lower pressure than the first oxygen-rich gas stream ii ) according to a second step a) increase the air liquefaction pressure in setting the blades of the main compressor and / or the second compressor which sets (s) this pressure b) is reduced, possibly to zero, the production of the second gas flow rich in oxygen (c) increases the withdrawal of the first gaseous flow rich in oxygen. 2. Procede selon la revendication 1 dans lequel le deuxieme debit gazeux riche en oxygene est produit en soutirant un debit liquide (36) de la colonne basse pression et en le pressurisant a la pression moins elevee avant de le vaporiser dans la ligne d'echange.  2. The method of claim 1 wherein the second oxygen-rich gas stream is produced by withdrawing a liquid flow (36) from the low pressure column and pressurizing it at the lower pressure before vaporizing it in the line of exchange. . 3. Procede selon la revendication 1 dans lequel le deuxieme debit gazeux riche en oxygene est produit en soutirant un debit gazeux d'une colonne de 10 melange (300) alimentee par de I'air ou de la colonne basse pression.  3. A process according to claim 1 wherein the second oxygen-rich gas stream is produced by withdrawing a gas flow from a mixing column (300) fed with air or a low pressure column. 4. Procede selon rune des revendications precedentes dans lequel le compresseur principal et eventuellement I'au moins un deuxieme compresseur (5) comprime(nt) tout I'air destine a I'appareil.  4. Method according to rune preceding claims wherein the main compressor and optionally the at least one second compressor (5) compresses (s) all air for the device. 5. Procede selon rune des revendications 1 a 3 dans lequel le compresseur principal comprime tout I'air destine a I'appareil et I'au moins un deuxieme compresseur (70, 71, 23) ne comprime qu'une partie de fair destine a I'appareil. 20  5. Method according to one of claims 1 to 3 wherein the main compressor compresses all the air intended for the apparatus and the at least one second compressor (70, 71, 23) compresses only part of fair intended for appliance. 20 6. Procede selon la revendication 5 dans lequel lors de la deuxieme marche, on augmente le debit envoye au deuxieme compresseur(70, 71, 23).  6. Method according to claim 5 wherein during the second step, the flow sent to the second compressor (70, 71, 23) is increased. 7. Procede selon la revendication 6 dans lequel une partie de I'air comprime dans le deuxieme compresseur (70, 71, 23) est detendu dans une turbine puis 25 envoye a la double colonne et dans lequel le debit detendu (15) pendant la deuxieme marche reduit par rapport a celui pendant la premiere marche.  The method of claim 6 wherein a portion of the compressed air in the second compressor (70, 71, 23) is expanded in a turbine and then sent to the double column and wherein the expanded flow (15) during the second step reduced compared to that during the first walk. 8. Procede selon rune des revendications 1 a 5 dans lequel lors de la deuxieme marche on maintient constant le debit envoye au deuxieme 30 compresseur (70, 71, 23) par rapport au meme debit pendant la premiere marche.  8. Method according to one of claims 1 to 5 wherein in the second step the flow sent to the second compressor (70, 71, 23) is kept constant with respect to the same flow during the first step. 9. Procede selon la revendication 8 dans lequel on augmente la quantite de gaz envoyee une turbine (19, 46, 72) entrainant le deuxieme compresseur (70, 1571, 23) dans la deuxieme marche par rapport a celle envoyee pendant la premiere marche.  9. The method of claim 8 wherein increasing the amount of gas sent a turbine (19, 46, 72) driving the second compressor (70, 1571, 23) in the second step compared to that sent during the first step. 10. Procede suivant une des revendications precedentes telle que le premier debit riche en oxygene (15, 59, 125) a une purete superieure a 98.5%, et le deuxieme debit riche en oxygene (115, 72, 137) a une purete inferieure a 98%.  10. Process according to one of the preceding claims, such that the first oxygen-rich flow (15, 59, 125) has a purity higher than 98.5%, and the second oxygen-rich flow (115, 72, 137) has a purity lower than 10.5%. 98%. 11. Procede selon rune des revendications precedentes dans lequel lors de la premiere marche on soutire de la double colonne en tant que produit final un debit liquide riche en oxygene (34, 501) et lors de la deuxieme marche le soutirage de ce debit est reduit, eventuellement a zero.  11. Method according to one of the preceding claims wherein in the first step is withdrawn from the double column as a final product oxygen-rich liquid flow (34, 501) and in the second step the withdrawal of this flow is reduced , possibly at zero. 12. Procede selon rune des revendications precedentes dans lequel la somme des premier et deuxieme debits riches en oxygene est substantiellement constante entre la premiere et la deuxieme marches.  12. A method according to one of the preceding claims wherein the sum of the first and second oxygen-rich feeds is substantially constant between the first and second steps. 13. Procede selon rune des revendications precedentes dans lequel pendant la premiere marche un debit d'air est detendu dans une turbine (4, 46, 72, 19) et envoye a la double colonne et pendant la deuxieme marche soit le debit detendu est rejete a ('atmosphere soit une partie du debit detendu est envoyee a la double colonne alors que le reste est rejete a ('atmosphere.  13. Method according to rune preceding claims wherein during the first march an air flow is expanded in a turbine (4, 46, 72, 19) and sent to the double column and during the second step is the debit expanded is rejected In the atmosphere, a part of the expanded flow is sent to the double column, while the rest is discharged to the atmosphere. 14. Procede selon ('une des revendications precedentes dans lequel pendant la deuxieme marche on envoie de ('air comprime a la double colonne provenant 25 d'un compresseur de secours.  14. A method according to one of the preceding claims wherein during the second step compressed air is supplied to the double column from a backup compressor. 15. Procede suivant une des revendications precedentes dans lequel une partie de ('air traite vient de soufflante de haut fourneau. 30  15. Process according to one of the preceding claims, in which a portion of the treated air comes from a blast furnace blower. 16. Procede selon ('une des revendications precedentes dans lequel pendant la premiere marche on produit un debit d'azote sous pression et/ou d'argon sous pression par vaporisation de liquide pressurise et pendant la deuxieme marche on reduit ou on arrete la production de ce(s) debit(s).  16. Process according to one of the preceding claims, in which during the first step a flow of pressurized nitrogen and / or argon is produced by vaporization of pressurized liquid and during the second step the production is reduced or stopped. of this (s) debit (s). 17. Procede selon rune des revendications precedentes dans lequel pendant la premiere marche on produit un debit d'azote liquide et/ou d'argon liquide comme produit final et pendant la deuxieme marche, on reduit ou on arrete cette (ces) production(s).  17. Process according to one of the preceding claims wherein during the first step a liquid nitrogen and / or liquid argon flow is produced as the final product and during the second step, this (these) production is reduced or stopped. ). 18. Procede selon rune des revendications precedentes dans lequel les premier et deuxieme debits riche en oxygene ont la meme purete ou des puretes differentes. 10  18. A method according to one of the preceding claims wherein the first and second oxygen-rich feeds have the same purity or different purities. 10 19. Procede de fourniture d'un debit d'oxygene haute pression dans lequel selon une premiere marche chacune de deux installations de separation d'air (ASU 1, ASU 2) fournit de I'oxygene haute pression (15) et selon une deuxieme marche, une premiere des deux installations (ASU 1) fournit un debit d'oxygene haute pression augmente par rapport a celui selon la premiere marche et la 15 deuxieme installation fournit un debit reduit, voire a zero ; au moins la premiere installation fonctionnant selon rune des revendications precedentes et fournissant en plus de sa production initiale d'oxygene haute pression au moins 50% de la quantite d'oxygene haute pression produite pendant la premiere marche par la deuxieme installation. 20  19. A method of supplying a high pressure oxygen stream in which, according to a first step, each of two air separation plants (ASU 1, ASU 2) supplies high pressure oxygen (15) and according to a second In operation, a first of the two installations (ASU 1) provides a high pressure oxygen flow rate higher than that of the first step and the second installation provides a reduced flow rate, or even zero; at least the first plant operating according to rune preceding claims and providing in addition to its initial production of high pressure oxygen at least 50% of the amount of high pressure oxygen produced during the first walk by the second installation. 20 20. Procede selon la revendication 19 dans lequel un compresseur d'air (C2) de la deuxieme installation envoie de fair comprime a la premiere installation pendant la deuxieme marche. 25  20. The method of claim 19 wherein an air compressor (C2) of the second plant sends compresses to the first installation during the second step. 25
FR0553893A 2005-12-15 2005-12-15 AIR SEPARATION METHOD BY CRYOGENIC DISTILLATION Expired - Fee Related FR2895068B1 (en)

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RU2008128818/06A RU2387934C2 (en) 2005-12-15 2006-12-14 Method to separate air into components by cryogenic distillation
KR1020087014219A KR101341278B1 (en) 2005-12-15 2006-12-14 Process for separating air by cryogenic distillation
CN2006800473992A CN101331374B (en) 2005-12-15 2006-12-14 Process for separating air by cryogenic distillation
BRPI0619924-0A BRPI0619924A2 (en) 2005-12-15 2006-12-14 cryogenic distillation air separation process
PCT/FR2006/051350 WO2007068858A2 (en) 2005-12-15 2006-12-14 Process for separating air by cryogenic distillation
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