JP4520668B2 - Air separation method and apparatus - Google Patents

Air separation method and apparatus Download PDF

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JP4520668B2
JP4520668B2 JP2001216565A JP2001216565A JP4520668B2 JP 4520668 B2 JP4520668 B2 JP 4520668B2 JP 2001216565 A JP2001216565 A JP 2001216565A JP 2001216565 A JP2001216565 A JP 2001216565A JP 4520668 B2 JP4520668 B2 JP 4520668B2
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nitrogen
oxygen
argon
air
distillation
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JP2003028569A (en
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信明 江越
博志 橘
浩 川上
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Taiyo Nippon Sanso Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04006—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
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
    • F25J3/04206—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04309—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04624—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 integrated mass and heat exchange, so-called non-adiabatic rectification, e.g. dephlegmator, reflux exchanger
    • F25J3/0463—Simultaneously between rectifying and stripping sections, i.e. double dephlegmator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04709—Producing crude argon in a crude argon column as an auxiliary column system in at least a dual pressure main column system
    • F25J3/04715—The auxiliary column system simultaneously produces 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
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04721—Producing pure argon, e.g. recovered from a crude argon column
    • F25J3/04727—Producing pure argon, e.g. recovered from a crude argon column using an auxiliary pure argon column for nitrogen rejection
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/08—Processes or apparatus using separation by rectification in a triple pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
    • F25J2205/04—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum in the feed line, i.e. upstream of the fractionation step
    • 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
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/58—Processes or apparatus involving steps for recycling of process streams the recycled stream being argon or crude 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
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/30—External or auxiliary boiler-condenser in general, e.g. without a specified fluid or one fluid is not a primary air component or an intermediate fluid
    • F25J2250/40—One 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
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/30—External or auxiliary boiler-condenser in general, e.g. without a specified fluid or one fluid is not a primary air component or an intermediate fluid
    • F25J2250/50—One fluid being oxygen

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

Description

【０００１】
【発明の属する技術分野】
本発明は、空気を低温蒸留することにより、窒素、酸素、およびアルゴンを分離する空気分離方法および装置に関する。
【０００２】
【従来の技術】
空気を低温蒸留して、窒素、酸素、アルゴン等を生産するには、高圧塔と低圧塔とからなる複式蒸留塔と、低圧塔に接続されたアルゴン塔とを備えた空気分離装置が用いられている。
近年、空気分離を行う際の動力消費量を抑制し製造コストを低減するため、熱交換型蒸留装置を利用した空気分離方法が提案されている。
例えば、特許第２８３３５９４号には、熱交換型蒸留装置を用いて、中純度の酸素（酸素濃度８５〜９９％）を製造する方法が開示されている。
ここに開示されている方法では、熱交換型蒸留装置として、２つの通路を熱交換可能となるように配設したプレートフィン熱交換器が用いられている。
この方法では、原料空気を熱交換型蒸留装置の第１通路で蒸留し、通路上部から低沸点の窒素に富む気相生成物を採取し、通路下部から高沸点の酸素に富む液相生成物を採取する。
第２通路では、上記酸素に富む液相生成物を、第１通路内の原料空気と熱交換させつつ蒸留し、通路上部から窒素に富む気相生成物を採取し、通路下部から製品酸素を得ることができる。
また、特開平８−３６４９９号公報にも、熱交換型蒸留装置を用いた空気分離方法が開示されている。
この方法では、原料空気を、熱交換型蒸留装置の第１通路で蒸留して、通路上部から窒素に富む気相生成物を導出し、これを凝縮させ、その一部を第２通路に還流液として導入し、第２の通路の下部から酸素濃度７０％以上の製品を採取する。
【０００３】
【発明が解決しようとする課題】
しかしながら、従来の空気分離方法において、熱交換効率を高め、十分な純度の製品を得るためには、原料空気を高圧にする必要がある。このため、消費動力が嵩む問題があった。
さらに、熱交換型蒸留装置を用いた従来の空気分離方法では、製造される製品が、窒素と酸素に限られており、同時にアルゴンを採取することができる方法が望まれていた。
本発明は、上記事情に鑑みてなされたもので、熱交換効率を高め、動力消費量を削減することができ、しかもアルゴンを採取することができる空気分離方法および装置を提供することを目的とする。
【０００４】
【課題を解決するための手段】
本発明の空気分離方法は、空気凝縮通路と、窒素蒸留通路と、これら通路と熱交換可能とされた酸素蒸留通路とを備えた熱交換型蒸留装置と、窒素蒸留塔と、アルゴン蒸留塔とを用い、（１）原料空気を圧縮した後、この原料空気を、空気凝縮通路において、酸素蒸留通路との熱交換により冷却して部分液化させ、気相の窒素富化空気と液相の酸素アルゴン富化空気とを分離し、（２）この窒素富化空気を、窒素蒸留通路において、酸素蒸留通路との熱交換により冷却しつつ蒸留して、窒素が濃縮された窒素濃縮物と、これより窒素濃度が低い窒素含有物とを分離し、窒素濃縮物を製品中圧窒素として回収し、（３）この窒素含有物と前記酸素アルゴン富化空気を、窒素蒸留塔において蒸留し、窒素が濃縮された製品低圧窒素と、酸素およびアルゴンが濃縮されたアルゴン含有粗酸素とを分離し、製品低圧窒素を回収し、（４）このアルゴン含有粗酸素を、酸素蒸留通路において、空気凝縮通路および窒素蒸留通路との熱交換により加熱しつつ蒸留し、酸素とアルゴンが濃縮されたアルゴン酸素原料を分離し、（５）このアルゴン酸素原料を、アルゴン蒸留塔において蒸留し、アルゴンが濃縮された製品アルゴンと、酸素が濃縮された製品液化酸素とを分離し、これら製品アルゴンおよび製品液化酸素を回収することを特徴とする。
本発明の空気分離方法は、アルゴン蒸留塔が、この蒸留塔からの導出液の一部を気化させてこの蒸留塔に戻すアルゴンリボイラと、この蒸留塔からの導出ガスの一部を液化させてこの蒸留塔に戻すアルゴンコンデンサを備え、窒素蒸留塔が、この蒸留塔内の窒素を気化させる窒素凝縮器を備え、窒素蒸留通路からの窒素濃縮物の一部を、アルゴンリボイラに加熱源として導入し、次いでアルゴンコンデンサに冷却源として導入し、次いで窒素凝縮器に加熱源として導入し、次いで窒素蒸留塔に導入する方法を採用してもよい。
本発明の空気分離方法は、圧縮した原料空気の一部をさらに圧縮し、得られた二次圧縮原料空気を、前記製品により冷却した後、空気凝縮通路に供給することができる。
本発明の空気分離方法では、製品液化酸素を、原料空気との熱交換により気化させることができる。
本発明では、製品液化酸素を、昇圧した後に回収することができる。
本発明では、窒素蒸留通路によって分離された窒素濃縮物の一部を圧縮した後、断熱膨張させ、この断熱膨張時に得られる動力を利用して前記窒素濃縮物の圧縮を行うことができる。
【０００５】
本発明の空気分離装置は、原料空気を圧縮する空気圧縮機と、圧縮された原料空気を冷却する主熱交換器と、冷却された原料空気を蒸留する熱交換型蒸留装置と、熱交換型蒸留装置を経た蒸留物をさらに蒸留する窒素蒸留塔と、窒素蒸留塔を経た蒸留物をさらに蒸留するアルゴン蒸留塔とを備え、熱交換型蒸留装置が、空気凝縮通路と、窒素蒸留通路と、これら通路と熱交換可能とされた酸素蒸留通路とを備え、空気凝縮通路が、原料空気を、酸素蒸留通路との熱交換により冷却して部分液化させ、気相の窒素富化空気と液相の酸素アルゴン富化空気とを得ることができるようにされ、窒素蒸留通路が、この窒素富化空気を、酸素蒸留通路との熱交換により冷却しつつ蒸留し、窒素が濃縮された窒素濃縮物である製品中圧窒素と、これより窒素濃度が低い窒素含有物とを得ることができるようにされ、窒素蒸留塔が、この窒素含有物と前記酸素アルゴン富化空気を蒸留して、窒素が濃縮された製品低圧窒素と、酸素およびアルゴンが濃縮されたアルゴン含有粗酸素とを得ることができるようにされ、酸素蒸留通路が、このアルゴン含有粗酸素を、空気凝縮通路および窒素蒸留通路との熱交換により加熱しつつ蒸留し、酸素およびアルゴンが濃縮されたアルゴン酸素原料を得ることができるようにされ、アルゴン蒸留塔が、このアルゴン酸素原料を蒸留し、アルゴンが濃縮された製品アルゴンと、酸素が濃縮された製品液化酸素とを得ることができるようにされていることを特徴とする。
本発明の空気分離装置では、アルゴン蒸留塔が、この蒸留塔からの導出液の一部を気化させてこの蒸留塔に戻すアルゴンリボイラと、この蒸留塔からの導出ガスの一部を液化させてこの蒸留塔に戻すアルゴンコンデンサを備え、窒素蒸留塔が、この蒸留塔内の窒素を気化させる窒素凝縮器を備え、窒素蒸留通路からの窒素濃縮物の一部を、アルゴンリボイラに加熱源として導入し、次いでアルゴンコンデンサに冷却源として導入し、次いで窒素凝縮器に加熱源として導入し、次いで窒素蒸留塔に導入することができる構成を採用することができる。
本発明の空気分離装置では、空気圧縮機で圧縮された原料空気の一部をさらに圧縮する二次圧縮機を備え、この圧縮機によって圧縮された二次圧縮原料空気を、主熱交換器を経て空気凝縮通路に供給することができるように構成することができる。
本発明の空気分離装置では、製品液化酸素を気化させる酸素蒸発器を備え、この酸素蒸発器が、原料空気との熱交換によって製品液化酸素を気化させることができるようにされている構成を採用することができる。
本発明の空気分離装置は、製品液化酸素を昇圧する昇圧ポンプを備えた構成とすることができる。
本発明の空気分離装置は、酸素蒸発器を経た原料空気を窒素蒸留塔に導入することができる構成を採用できる。
【０００６】
【発明の実施の形態】
図１は、本発明の空気分離装置の第１の実施形態を示す系統図である。
ここに示す空気分離装置１０は、原料空気ＲAを圧縮する空気圧縮機１と、圧縮された原料空気の圧縮熱を取り除く空気予冷器２と、空気予冷器２を経た原料空気中の不純物（水分、二酸化炭素等）を除去する精製器３と、精製器３を経た原料空気を冷却する主熱交換器４と、主熱交換器４を経た原料空気を蒸留する熱交換型蒸留装置５と、熱交換型蒸留装置５を経た蒸留物をさらに蒸留する窒素蒸留塔６と、窒素蒸留塔６を経た蒸留物をさらに蒸留するアルゴン蒸留塔７と、気液分離器１６、８と、膨張タービン９と、過冷器１１と、昇圧機１３とを主要な構成機器とする。また符号１５は保冷槽を示す。
【０００７】
熱交換型蒸留装置５は、空気凝縮通路５１と、窒素蒸留通路５２と、これら通路５１、５２と熱交換可能とされた酸素蒸留通路５３とを備えている。
熱交換型蒸留装置５としては、プレートフィン式熱交換器を使用することができる。
なお、図示例の熱交換型蒸留装置５では、通路５１〜５３が一体化されているが、本発明では、熱交換型蒸留装置を２つに分割してもよい。
すなわち、酸素蒸留通路を上部通路と下部通路とに分割し、この上部通路と窒素蒸留通路を有する第１熱交換型蒸留部と、下部通路と空気凝縮通路とを有する第２熱交換型蒸留部とを備えた熱交換型蒸留装置を使用することもできる。
【０００８】
アルゴン蒸留塔７は、アルゴンリボイラ７ａと、アルゴンコンデンサ７ｂとを備えている。
アルゴンリボイラ７ａは、蒸留塔７からの導出液の一部を気化させて蒸留塔７に戻すことができるようになっている。
アルゴンコンデンサ７ｂは、蒸留塔７からの導出ガスの一部を液化させて蒸留塔７に戻すことができるようになっている。
【０００９】
窒素蒸留塔６は、この蒸留塔６内の窒素を気化させる窒素凝縮器６ａを備えている。
昇圧機１３は、膨張タービン９での断熱膨張の際に得られる動力を利用して駆動することができる構成とするのが好ましい。
【００１０】
次に、この空気分離装置１０を使用した場合を例として、本発明の空気分離方法の第１の実施形態を説明する。
まず、大気などの原料空気ＲAを、空気圧縮機１で圧縮し（例えば約３９０kＰaに圧縮）、空気予冷器２で常温まで冷却した後、精製器３において、原料空気中の水分、二酸化炭素等の不純物を吸着除去する。
【００１１】
次いで、精製器３を経た原料空気を、主熱交換器４において、後述する製品窒素、製品液化酸素等の低温流体との熱交換により約−１７８℃に冷却し、部分液化させる。
主熱交換器４を経た原料空気は、気液分離器１６に導入され、気相の精製原料空気と、液相の酸素アルゴン富化空気とに分離される。
【００１２】
気相の精製原料空気は、管路Ｌ1を経て、熱交換型蒸留装置５の空気凝縮通路５１に、その上部から導入される。
空気凝縮通路５１に導入された精製原料空気は、酸素蒸留通路５３内の流体（後述するアルゴン含有粗酸素）との熱交換によって冷却されつつ空気凝縮通路５１内を下降し、この過程で部分液化し、気液混和状態となる。
空気凝縮通路５１を経た気液混和状態の精製原料空気は、通路５１の下部から管路Ｌ2を通して気液分離器８に導入され、この気液分離器８において、気相の窒素富化空気と液相の酸素アルゴン富化空気とに分離される。
【００１３】
気相の窒素富化空気は、気液分離器８の上部から導出され、管路Ｌ5を通して窒素蒸留通路５２の下部に導入される。
この窒素富化空気は、窒素蒸留通路５２内を上昇する過程で、酸素蒸留通路５３内の流体（アルゴン含有粗酸素）と熱交換して冷却されつつ蒸留され、気相中に窒素が濃縮する。
得られた窒素濃縮物（例えば窒素濃度が９８％以上、酸素含有量２％以下）は、窒素蒸留通路５２の上部から管路Ｌ6を通して導出され、主熱交換器４を経て製品中圧窒素ＭGNとして回収される。
【００１４】
この窒素濃縮物（製品中圧窒素）の一部は、管路Ｌ23を通して昇圧機１３に導入されて圧縮され、冷却後、膨張タービン９で断熱膨張され、管路Ｌ24により主熱交換器４に導入される。これによって、原料空気の冷却を効率よく行うことができる。主熱交換器４を経た窒素濃縮物は、排出ガスＷＧとして排出される。
昇圧機１３で窒素濃縮物の昇圧を行う際には、この昇圧機１３を、膨張タービン９で窒素濃縮物を断熱膨張させる際に得られる動力を利用して駆動するのが好ましい。これによって、動力効率を向上させることができる。
【００１５】
窒素蒸留通路５２内の蒸留過程では、液相中の窒素濃度が低くなり、低窒素濃度の液状の窒素含有物が得られる。
この窒素含有物は、窒素蒸留通路５２下部から管路Ｌ7によって導出され、管路Ｌ3を通って過冷器１１に導入され、管路Ｌ4の減圧弁Ｖ1で減圧されて、窒素蒸留塔６の下部に供給される。
【００１６】
上述の気液分離器１６で得られた液相の酸素アルゴン富化空気は、管路Ｌ26、Ｌ3を通して過冷器１１に導入され、減圧弁Ｖ1で減圧された後、窒素蒸留塔６の下部に供給される。
また気液分離器８で得られた液相の酸素アルゴン富化空気も、管路Ｌ3を通って過冷器１１に導入された後、窒素蒸留塔６の下部に導入される。
【００１７】
窒素蒸留塔６における蒸留によって、気相中に窒素が濃縮するとともに、液相中に酸素とアルゴンが濃縮される。
気相生成物（例えば窒素濃度９８％以上、酸素含有量２％以下）は、窒素蒸留塔６の上部から管路Ｌ12を通して導出され、過冷器１１、管路Ｌ13を経て主熱交換器４に導入され、ここで加熱された後、製品低圧窒素ＧNとして回収される。
【００１８】
一方、液相の酸素アルゴン濃縮物であるアルゴン含有粗酸素は、窒素蒸留塔６の下部から管路Ｌ14を通して導出され、熱交換型蒸留装置５の酸素蒸留通路５３に導入される。
アルゴン含有粗酸素は、酸素蒸留通路５３内を下降する過程で、空気凝縮通路５１内の精製原料空気、および窒素蒸留通路５２内の窒素富化空気と熱交換して加熱される。
この過程においては、蒸留により気相中の窒素濃度が高くなり、液相中の酸素とアルゴンの濃度が高くなる。これによって、気相の窒素含有気体と、液相の酸素アルゴン濃縮物であるアルゴン酸素原料（例えばアルゴン含有率３％）とが得られる。
窒素含有気体は、酸素蒸留通路５３の上部から、管路Ｌ15を通して窒素蒸留塔６の下部に再び導入される。
【００１９】
一方、液相のアルゴン酸素原料は、酸素蒸留通路５３の下部から管路Ｌ16を通して導出され、減圧弁Ｖ4で減圧された後、アルゴン蒸留塔７の下部に導入される。
【００２０】
アルゴン蒸留塔７では、アルゴン酸素原料の蒸留により、気相中にアルゴンが濃縮し、液相中に酸素が濃縮する。
これによって、気相のアルゴン濃縮物（例えばアルゴン濃度９５％以上）と、液相の酸素濃縮物である製品液化酸素（例えば酸素濃度９８％以上）とが得られる。
【００２１】
得られたアルゴン濃縮物は、アルゴン蒸留塔７の上部から、管路Ｌ20を通して主熱交換器４に導入され、ここで原料空気との熱交換により加熱された後、製品アルゴンＧArとして回収される。
原料空気からのアルゴンの回収率は、例えば約３５％となる。
アルゴン蒸留塔７から導出されたアルゴン濃縮物（製品アルゴン）の一部は、管路Ｌ21を通してアルゴンコンデンサ７ｂに導入され、ここで液化し、管路Ｌ22を通してアルゴン蒸留塔７の上部に再び導入される。
【００２２】
一方、製品液化酸素は、アルゴン蒸留塔７の下部から、管路Ｌ17を通して主熱交換器４に導入され、ここで加熱された後、製品液化酸素ＧOとして回収される。
アルゴン蒸留塔７から導出された製品液化酸素の一部は、管路Ｌ18を通してアルゴンリボイラ７ａに導入され、ここで気化し、管路Ｌ19を通してアルゴン蒸留塔７の下部に再び導入される。
【００２３】
窒素蒸留通路５２からの窒素濃縮物（製品中圧窒素ＭＧN）の一部は、管路Ｌ6a、主熱交換器４を経て、窒素圧縮機１２で圧縮され、再び主熱交換器４で冷却された後、管路Ｌ8を通して、加熱源としてアルゴンリボイラ７ａに導入される。
アルゴンリボイラ７ａを経た窒素濃縮物は、管路Ｌ9、過冷器11を通って、減圧弁Ｖ2で減圧された後、アルゴンコンデンサ７ｂに冷却源として導入される。アルゴンコンデンサ７ｂを経た窒素濃縮物は、管路Ｌ10を通して、窒素蒸留塔６下部の窒素凝縮器６ａに加熱源として導入される。これによって、窒素蒸留塔６内の流体が加熱され、液相中の窒素の気化が促進される。
窒素凝縮器６ａを経た窒素濃縮物は、管路Ｌ11、過冷器11を通って、減圧弁Ｖ3で減圧されて、還流液として窒素蒸留塔６の上部に導入される。
【００２４】
本実施形態の空気分離方法では、空気凝縮通路５１と、窒素蒸留通路５２と、酸素蒸留通路５３とを備えた熱交換型蒸留装置５と、窒素蒸留塔６と、アルゴン蒸留塔７とを用いるので、原料空気と窒素富化空気とアルゴン含有粗酸素との間の熱交換を効率よく行わせることができる。
このため、空気圧縮機１において原料空気の圧力を低く設定することができる。例えば、従来方法において必要な原料空気圧力約５００ｋＰａを、約３９０ｋＰａとすることができる。
従って、動力消費量を大幅に削減することができる。例えば、複式蒸留塔とアルゴン塔を備えた従来の空気分離装置を用いた場合に比べ、約１０％の省エネルギー化が可能となる。
また、アルゴン蒸留塔７を用いるので、アルゴンの採取が可能となる。
【００２５】
なお、本発明では、図１中破線で示す管路Ｌ25を用いて、精製器３からの精製原料空気の一部を、二次圧縮機１４を用いて約４００kＰaまで二次圧縮した後、管路Ｌ1を通して空気凝縮通路５１に導入することもできる。
この場合には、空気圧縮機１での原料空気の圧力をさらに低く（例えば約３５０kＰa）することができる。このため、動力消費量をさらに削減できる。
また、本発明では、管路Ｌ17を通して導出される製品液化酸素の圧力を、昇圧ポンプ１７によって圧力を高めて回収することもできる。
【００２６】
次に、本発明の空気分離装置の第２の実施形態を説明する。
図２は、本実施形態の空気分離装置を示す系統図である。
ここに示す空気分離装置３０は、製品液化酸素を導出する管路Ｌ17に、製品液化酸素を気化させる酸素蒸発器３１が設けられている点、アルゴン蒸留塔７で得られたアルゴン濃縮物（製品アルゴン）をさらに蒸留する高純アルゴン蒸留塔３４が設けられている点で、図１に示す空気分離装置１０と異なる。
【００２７】
酸素蒸発器３１は、製品液化酸素を、原料空気との熱交換により気化させることができるようになっている。
高純アルゴン蒸留塔３４は、蒸留塔３４からの導出液の一部を気化させて蒸留塔３４に戻す高純アルゴンリボイラ３４ａと、蒸留塔３４からの導出ガスの一部を液化させて蒸留塔３４に戻す高純アルゴンコンデンサ３４ｂとを備えている。
高純アルゴンコンデンサ３４ｂは、アルゴンコンデンサ７ｂ、窒素凝縮器６ａ、過冷器１１を経た窒素濃縮物の一部を用いて、上記導出ガスを冷却することができるようになっている。
【００２８】
次に、この空気分離装置３０を使用した場合を例として、本発明の空気分離方法の第２の実施形態を説明する。
原料空気は、空気圧縮機１で圧縮され（例えば圧力約３９０ｋＰa）、空気予冷器２で常温まで冷却された後、精製器３で不純物を吸着除去し、主熱交換器４で冷却され、管路Ｌ1を通して熱交換型蒸留装置５の空気凝縮通路５１に導入される。
原料空気の一部は、管路Ｌ31を通して酸素蒸発器３１に導入され、ここで管路Ｌ17からの製品液化酸素との熱交換により冷却された後、管路Ｌ32、Ｌ3、Ｌ4を通して窒素蒸留塔６に導入される。
【００２９】
アルゴン蒸留塔７の下部から、管路Ｌ17を通して導出された製品液化酸素は、酸素蒸発器３１に導入され、ここで原料空気との熱交換により気化した後に、主熱交換器４を経て製品液化酸素ＧOとして回収される。
【００３０】
この空気分離方法では、アルゴン蒸留塔７の上部から管路Ｌ20を通して導出されるアルゴン濃縮物（製品アルゴンＧAr）を、アルゴン圧縮機３２で圧縮し、アルゴン精製器３３にて酸素分等を触媒等で除去して精製する。
次いで、精製されたアルゴン濃縮物を、主熱交換器４で冷却した後、管路Ｌ33を通して高純アルゴンリボイラ３４ａに導入する。
高純アルゴンリボイラ３４ａにおいて、アルゴン濃縮物は、高純アルゴン蒸留塔３４からの導出液（後述する高純製品アルゴン）との熱交換により冷却され、液化した後、管路Ｌ34、減圧弁Ｖ30を経て高純アルゴン蒸留塔３４に導入される。
【００３１】
高純アルゴン蒸留塔３４では、導入されたアルゴン濃縮物が蒸留され、気相中の低沸点成分（窒素等）濃度が高められ、液相中のアルゴン濃度が高められる。
高純アルゴン蒸留塔３４内の低沸点成分含有気体は、管路Ｌ37、Ｌ41を通して導出され、管路Ｌ12に導かれ、上記製品低圧窒素に合流して、主熱交換器４を経て回収される。
低沸点成分含有気体の一部は、管路Ｌ37、Ｌ38を通して高純アルゴンコンデンサ３４ｂに導入され、ここで高沸点成分が液化した後、管路Ｌ39を通して高純アルゴン蒸留塔３４に戻される。
【００３２】
一方、高純アルゴン蒸留塔３４で得られた高濃度アルゴンは、蒸留塔３４の下部から、管路Ｌ40を通して導出され、高純製品アルゴンＰＡｒ（例えば窒素１ｐｐｍ以下、酸素０.１ｐｐｍ以下）として回収される。
高濃度アルゴン（高純製品アルゴン）の一部は、管路Ｌ35により高純アルゴンリボイラ３４ａに導入され、ここで気化した後、管路Ｌ36から蒸留塔３４下部に戻される。
【００３３】
また、本発明では、管路Ｌ17を通して導出される製品液化酸素の圧力を、昇圧ポンプ１７によって圧力を高め、この製品液化酸素を酸素蒸発器３１で気化させて回収することもできる。
【００３４】
本実施形態の空気分離方法では、第１の実施形態の方法と同様に、熱交換型蒸留装置５と、窒素蒸留塔６と、アルゴン蒸留塔７とを用いるので、原料空気と窒素富化空気とアルゴン含有粗酸素との間の熱交換を効率よく行わせ、原料空気の圧力を低く設定することができる。
従って、動力消費量を大幅に削減することができる。
また、アルゴン蒸留塔７を用いるので、アルゴンの採取が可能となる。
【００３５】
【発明の効果】
本発明の空気分離方法では、空気凝縮通路と、窒素蒸留通路と、酸素蒸留通路とを備えた熱交換型蒸留装置と、窒素蒸留塔と、アルゴン蒸留塔とを用いるので、原料空気と窒素富化空気とアルゴン含有粗酸素との間の熱交換を効率よく行わせることができる。
このため、原料空気の圧力を低く設定することができ、動力消費量を大幅に削減することができる。
また、アルゴン蒸留塔を用いるので、アルゴンの採取が可能となる。
【図面の簡単な説明】
【図１】 本発明の空気分離装置の第１の実施形態を示す系統図。
【図２】 本発明の空気分離装置の第２の実施形態を示す系統図。
【符号の説明】
１・・・空気圧縮機、４・・・主熱交換器、５・・・熱交換型蒸留装置、６・・・窒素蒸留塔、６ａ・・・窒素凝縮器、７・・・アルゴン蒸留塔、７ａ・・・アルゴンリボイラ、７ｂ・・・アルゴンコンデンサ、８・・・気液分離器、９・・・膨張タービン、１０、３０・・・空気分離装置、１３・・・昇圧機、１４・・・二次圧縮機、１７・・・昇圧ポンプ、３１・・・酸素蒸発器、５１・・・空気凝縮通路、５２・・・窒素蒸留通路、５３・・・酸素蒸留通路、ＲA・・・原料空気、ＭＧN・・・製品中圧窒素、ＧN・・・製品低圧窒素、ＧO・・・製品液化酸素、ＧAr・・・製品アルゴン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air separation method and apparatus for separating nitrogen, oxygen, and argon by low-temperature distillation of air.
[0002]
[Prior art]
In order to produce nitrogen, oxygen, argon, etc. by low-temperature distillation of air, an air separation apparatus including a double distillation column composed of a high-pressure column and a low-pressure column and an argon column connected to the low-pressure column is used. ing.
In recent years, an air separation method using a heat exchange distillation apparatus has been proposed in order to suppress power consumption when air separation is performed and to reduce manufacturing costs.
For example, Japanese Patent No. 2833594 discloses a method for producing medium-purity oxygen (oxygen concentration of 85 to 99%) using a heat exchange distillation apparatus.
In the method disclosed here, a plate fin heat exchanger in which two passages are arranged so as to be capable of heat exchange is used as a heat exchange type distillation apparatus.
In this method, raw air is distilled in the first passage of the heat exchange distillation apparatus, a low-boiling nitrogen-rich gas phase product is collected from the upper portion of the passage, and a high-boiling-point oxygen-rich liquid phase product is taken from the lower portion of the passage. Collect.
In the second passage, the oxygen-rich liquid phase product is distilled while exchanging heat with the raw air in the first passage, and a nitrogen-rich gas phase product is collected from the upper portion of the passage, and product oxygen is taken from the lower portion of the passage. Obtainable.
Japanese Patent Application Laid-Open No. 8-36499 also discloses an air separation method using a heat exchange distillation apparatus.
In this method, the raw material air is distilled in the first passage of the heat exchange distillation apparatus, the vapor phase product rich in nitrogen is derived from the upper portion of the passage, condensed, and a part thereof is refluxed to the second passage. The product is introduced as a liquid, and a product having an oxygen concentration of 70% or more is collected from the lower part of the second passage.
[0003]
[Problems to be solved by the invention]
However, in the conventional air separation method, in order to increase the heat exchange efficiency and obtain a product with sufficient purity, it is necessary to increase the pressure of the raw material air. For this reason, there was a problem that power consumption increased.
Furthermore, in the conventional air separation method using a heat exchange type distillation apparatus, the products to be produced are limited to nitrogen and oxygen, and a method capable of collecting argon at the same time is desired.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an air separation method and apparatus capable of increasing heat exchange efficiency, reducing power consumption, and collecting argon. To do.
[0004]
[Means for Solving the Problems]
The air separation method of the present invention includes an air condensing passage, a nitrogen distillation passage, a heat exchange type distillation apparatus provided with an oxygen distillation passage that can exchange heat with these passages, a nitrogen distillation tower, and an argon distillation tower. (1) After compressing the raw air, the raw air is cooled in the air condensing passage by heat exchange with the oxygen distillation passage to be partially liquefied, and the gaseous nitrogen enriched air and the liquid phase oxygen (2) separating the nitrogen-enriched air from the nitrogen-distilled passage by cooling it in the nitrogen distillation passage by heat exchange with the oxygen distillation passage, The nitrogen content is separated from the nitrogen content having a lower nitrogen concentration, and the nitrogen concentrate is recovered as medium-pressure nitrogen. (3) The nitrogen content and the oxygen-argon enriched air are distilled in a nitrogen distillation column, Concentrated product low pressure nitrogen, oxygen and The argon-containing crude oxygen enriched with lugon is separated, and the product low-pressure nitrogen is recovered. (4) The argon-containing crude oxygen is heated in the oxygen distillation passage by heat exchange with the air condensing passage and the nitrogen distillation passage. (5) This argon oxygen raw material is distilled in an argon distillation column, and product argon enriched with argon and product liquefaction enriched with oxygen are separated. It is characterized by separating oxygen and recovering these product argon and product liquefied oxygen.
In the air separation method of the present invention, an argon distillation tower vaporizes a part of the liquid derived from the distillation tower and returns it to the distillation tower, and liquefies a part of the gas derived from the distillation tower. Argon condenser that returns to this distillation column is equipped, nitrogen distillation column is equipped with a nitrogen condenser that vaporizes the nitrogen in this distillation column, and a part of the nitrogen concentrate from the nitrogen distillation passage is introduced into the argon reboiler as a heating source Then, a method may be employed in which the gas is introduced into the argon condenser as a cooling source, then introduced into the nitrogen condenser as a heating source, and then introduced into the nitrogen distillation column.
In the air separation method of the present invention, a part of the compressed raw material air can be further compressed, and the obtained secondary compressed raw material air can be cooled by the product and then supplied to the air condensing passage.
In the air separation method of the present invention, product liquefied oxygen can be vaporized by heat exchange with raw material air.
In the present invention, the product liquefied oxygen can be recovered after the pressure is increased.
In this invention, after compressing a part of nitrogen concentrate isolate | separated by the nitrogen distillation channel | path, it can carry out adiabatic expansion and can compress the said nitrogen concentrate using the power obtained at the time of this adiabatic expansion.
[0005]
The air separation device of the present invention includes an air compressor that compresses raw material air, a main heat exchanger that cools the compressed raw material air, a heat exchange distillation device that distills the cooled raw material air, and a heat exchange type A nitrogen distillation column that further distills the distillate that has passed through the distillation apparatus; and an argon distillation tower that further distills the distillate that has passed through the nitrogen distillation tower, wherein the heat exchange distillation apparatus includes an air condensing passage, a nitrogen distillation passage, These passages and an oxygen distillation passage capable of heat exchange are provided, and the air condensing passage cools and partially liquefies the raw material air by heat exchange with the oxygen distillation passage. The nitrogen-enriched air, and the nitrogen distillation passage is distilled while cooling the nitrogen-enriched air by heat exchange with the oxygen distillation passage, and the nitrogen concentrate is enriched with nitrogen Product medium pressure nitrogen and more nitrogen Low concentration nitrogen-containing product, and a nitrogen distillation column distills the nitrogen-containing product and the oxygen-argon-enriched air to produce nitrogen-concentrated product low-pressure nitrogen, oxygen and argon. Is obtained, and the oxygen distillation passage distills the argon-containing crude oxygen while heating it by heat exchange with the air condensing passage and the nitrogen distillation passage. Argon-enriched argon oxygen raw material can be obtained, and an argon distillation column distills the argon-oxygen raw material to obtain product argon enriched with argon and product liquefied oxygen enriched with oxygen. It is made to be able to do it.
In the air separation apparatus of the present invention, the argon distillation column is configured to vaporize a part of the liquid derived from the distillation column and return it to the distillation column, and to liquefy a part of the gas derived from the distillation column. Argon condenser that returns to this distillation column is equipped, nitrogen distillation column is equipped with a nitrogen condenser that vaporizes the nitrogen in this distillation column, and a part of the nitrogen concentrate from the nitrogen distillation passage is introduced into the argon reboiler as a heating source Then, it is possible to adopt a configuration that can be introduced into the argon condenser as a cooling source, then introduced into the nitrogen condenser as a heating source, and then introduced into the nitrogen distillation column.
The air separation device of the present invention includes a secondary compressor that further compresses part of the raw air compressed by the air compressor, and the secondary compressed raw air compressed by the compressor is supplied to the main heat exchanger. It can comprise so that it can supply to an air condensing passage via.
The air separation device of the present invention includes an oxygen evaporator that vaporizes product liquefied oxygen, and the oxygen evaporator employs a configuration that can vaporize product liquefied oxygen by heat exchange with raw material air. can do.
The air separation device of the present invention can be configured to include a booster pump that pressurizes product liquefied oxygen.
The air separation device of the present invention can employ a configuration that can introduce the raw material air that has passed through the oxygen evaporator into the nitrogen distillation column.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system diagram showing a first embodiment of an air separation device of the present invention.
The air separation device 10 shown here includes an air compressor 1 that compresses the raw material air RA, an air precooler 2 that removes the compression heat of the compressed raw material air, and impurities (moisture content) in the raw material air that has passed through the air precooler 2. , Carbon dioxide, etc.), a main heat exchanger 4 that cools the raw air that has passed through the purifier 3, a heat exchange distillation apparatus 5 that distills the raw air that has passed through the main heat exchanger 4, A nitrogen distillation column 6 that further distills the distillate that has passed through the heat exchange distillation apparatus 5, an argon distillation column 7 that further distills the distillate that has passed through the nitrogen distillation column 6, gas-liquid separators 16 and 8, and an expansion turbine 9 The supercooler 11 and the booster 13 are the main components. Reference numeral 15 denotes a cold storage tank.
[0007]
The heat exchange distillation apparatus 5 includes an air condensing passage 51, a nitrogen distillation passage 52, and an oxygen distillation passage 53 that can exchange heat with the passages 51 and 52.
As the heat exchange type distillation apparatus 5, a plate fin type heat exchanger can be used.
In the illustrated heat exchange distillation apparatus 5, the passages 51 to 53 are integrated. However, in the present invention, the heat exchange distillation apparatus may be divided into two.
That is, the oxygen distillation passage is divided into an upper passage and a lower passage, a first heat exchange distillation portion having the upper passage and the nitrogen distillation passage, and a second heat exchange distillation portion having the lower passage and the air condensation passage. It is also possible to use a heat exchange distillation apparatus equipped with
[0008]
The argon distillation column 7 includes an argon reboiler 7a and an argon condenser 7b.
The argon reboiler 7 a is configured to vaporize a part of the derived liquid from the distillation column 7 and return it to the distillation column 7.
The argon condenser 7 b can liquefy a part of the derived gas from the distillation column 7 and return it to the distillation column 7.
[0009]
The nitrogen distillation column 6 includes a nitrogen condenser 6 a that vaporizes nitrogen in the distillation column 6.
The booster 13 is preferably configured to be able to be driven using power obtained during adiabatic expansion in the expansion turbine 9.
[0010]
Next, the first embodiment of the air separation method of the present invention will be described by taking the case of using this air separation device 10 as an example.
First, the raw material air RA such as the atmosphere is compressed by the air compressor 1 (for example, compressed to about 390 kPa), cooled to room temperature by the air precooler 2, and then the water in the raw material air, carbon dioxide, etc. To remove impurities.
[0011]
Next, the raw material air that has passed through the purifier 3 is cooled to about −178 ° C. in the main heat exchanger 4 by heat exchange with a low-temperature fluid such as product nitrogen and product liquefied oxygen described later, and is partially liquefied.
The raw material air that has passed through the main heat exchanger 4 is introduced into the gas-liquid separator 16 and separated into gas-phase purified raw material air and liquid-phase oxygen-argon-enriched air.
[0012]
The gas-phase purified raw material air is introduced from above into the air condensing passage 51 of the heat exchange distillation apparatus 5 via the pipe L1.
The purified raw material air introduced into the air condensing passage 51 descends in the air condensing passage 51 while being cooled by heat exchange with a fluid in the oxygen distillation passage 53 (argon-containing crude oxygen described later), and is partially liquefied in this process. Then, it becomes a gas-liquid mixed state.
The purified raw material air mixed with gas and liquid through the air condensing passage 51 is introduced into the gas-liquid separator 8 from the lower portion of the passage 51 through the pipe L2, and in this gas-liquid separator 8, the gas-phase nitrogen-enriched air Separated into liquid phase oxygen-argon enriched air.
[0013]
The gas-phase nitrogen-enriched air is led out from the upper part of the gas-liquid separator 8 and introduced into the lower part of the nitrogen distillation passage 52 through the pipe line L5.
This nitrogen-enriched air is distilled while being cooled by exchanging heat with the fluid (argon-containing crude oxygen) in the oxygen distillation passage 53 in the process of rising in the nitrogen distillation passage 52, and nitrogen is concentrated in the gas phase. .
The obtained nitrogen concentrate (for example, the nitrogen concentration is 98% or more and the oxygen content is 2% or less) is led out from the upper part of the nitrogen distillation passage 52 through the pipe L6, passes through the main heat exchanger 4 and is the product intermediate pressure nitrogen MGN. As recovered.
[0014]
Part of this nitrogen concentrate (product medium pressure nitrogen) is introduced into the booster 13 through the line L23 and compressed, and after cooling, is adiabatically expanded in the expansion turbine 9, and is transferred to the main heat exchanger 4 through the line L24. be introduced. Thereby, the raw material air can be efficiently cooled. The nitrogen concentrate that has passed through the main heat exchanger 4 is discharged as an exhaust gas WG.
When boosting the nitrogen concentrate with the booster 13, it is preferable to drive the booster 13 using the power obtained when the expansion concentrate 9 adiabatically expands the nitrogen concentrate. Thereby, power efficiency can be improved.
[0015]
In the distillation process in the nitrogen distillation passage 52, the nitrogen concentration in the liquid phase is lowered, and a liquid nitrogen-containing material having a low nitrogen concentration is obtained.
This nitrogen-containing material is led out from the lower part of the nitrogen distillation passage 52 through the pipe L7, introduced into the supercooler 11 through the pipe L3, and decompressed by the pressure reducing valve V1 of the pipe L4. Supplied at the bottom.
[0016]
The liquid-phase oxygen-argon-enriched air obtained in the gas-liquid separator 16 is introduced into the supercooler 11 through the pipes L26 and L3, depressurized by the pressure reducing valve V1, and then the lower part of the nitrogen distillation column 6 To be supplied.
The liquid-phase oxygen-argon-enriched air obtained in the gas-liquid separator 8 is also introduced into the subcooler 11 through the line L3 and then introduced into the lower part of the nitrogen distillation column 6.
[0017]
The distillation in the nitrogen distillation column 6 concentrates nitrogen in the gas phase and oxygen and argon in the liquid phase.
A gas phase product (for example, a nitrogen concentration of 98% or more and an oxygen content of 2% or less) is led out from the upper part of the nitrogen distillation column 6 through the pipe L12, and passes through the supercooler 11 and the pipe L13 to the main heat exchanger 4. And is heated here and then recovered as product low pressure nitrogen GN.
[0018]
On the other hand, argon-containing crude oxygen, which is a liquid-phase oxygen-argon concentrate, is led out from the lower part of the nitrogen distillation column 6 through the pipe L 14 and introduced into the oxygen distillation passage 53 of the heat exchange distillation apparatus 5.
The argon-containing crude oxygen is heated by exchanging heat with purified raw material air in the air condensing passage 51 and nitrogen-enriched air in the nitrogen distillation passage 52 in the process of descending the oxygen distillation passage 53.
In this process, the nitrogen concentration in the gas phase is increased by distillation, and the oxygen and argon concentrations in the liquid phase are increased. As a result, a gas-phase nitrogen-containing gas and an argon-oxygen raw material (for example, an argon content of 3%) that is a liquid-phase oxygen-argon concentrate are obtained.
The nitrogen-containing gas is reintroduced from the upper part of the oxygen distillation passage 53 into the lower part of the nitrogen distillation column 6 through the line L15.
[0019]
On the other hand, the liquid-phase argon oxygen raw material is led out from the lower part of the oxygen distillation passage 53 through the pipe L16, depressurized by the pressure reducing valve V4, and then introduced into the lower part of the argon distillation column 7.
[0020]
In the argon distillation column 7, argon is concentrated in the gas phase and oxygen is concentrated in the liquid phase by distillation of the argon oxygen raw material.
As a result, a gas-phase argon concentrate (for example, an argon concentration of 95% or more) and a product liquefied oxygen (for example, an oxygen concentration of 98% or more) that is a liquid-phase oxygen concentrate are obtained.
[0021]
The obtained argon concentrate is introduced into the main heat exchanger 4 from the upper part of the argon distillation column 7 through the line L20, and is heated here by heat exchange with the raw material air, and then recovered as product argon GAr. .
The recovery rate of argon from the raw air is, for example, about 35%.
A part of the argon concentrate (product argon) derived from the argon distillation column 7 is introduced into the argon condenser 7b through the line L21, liquefied here, and again introduced into the upper part of the argon distillation column 7 through the line L22. The
[0022]
On the other hand, the product liquefied oxygen is introduced into the main heat exchanger 4 from the lower part of the argon distillation column 7 through the line L17, heated there, and then recovered as product liquefied oxygen GO.
Part of the product liquefied oxygen led out from the argon distillation column 7 is introduced into the argon reboiler 7a through the line L18, vaporized therein, and again introduced into the lower part of the argon distillation column 7 through the line L19.
[0023]
A part of the nitrogen concentrate (product medium pressure nitrogen MGN) from the nitrogen distillation passage 52 is compressed by the nitrogen compressor 12 via the line L6a and the main heat exchanger 4, and cooled again by the main heat exchanger 4. After that, it is introduced into the argon reboiler 7a as a heating source through the pipe L8.
The nitrogen concentrate that has passed through the argon reboiler 7a passes through the line L9 and the supercooler 11, and after being decompressed by the pressure reducing valve V2, is introduced into the argon condenser 7b as a cooling source. The nitrogen concentrate that has passed through the argon condenser 7b is introduced as a heating source into the nitrogen condenser 6a at the lower part of the nitrogen distillation column 6 through the pipe L10. As a result, the fluid in the nitrogen distillation column 6 is heated, and the vaporization of nitrogen in the liquid phase is promoted.
The nitrogen concentrate that has passed through the nitrogen condenser 6a is reduced in pressure by the pressure reducing valve V3 through the line L11 and the supercooler 11, and is introduced into the upper portion of the nitrogen distillation column 6 as a reflux liquid.
[0024]
In the air separation method of the present embodiment, the heat exchange type distillation apparatus 5 including the air condensing passage 51, the nitrogen distillation passage 52, and the oxygen distillation passage 53, the nitrogen distillation tower 6, and the argon distillation tower 7 are used. Therefore, heat exchange between the raw air, the nitrogen-enriched air, and the argon-containing crude oxygen can be efficiently performed.
For this reason, in the air compressor 1, the pressure of raw material air can be set low. For example, the raw material air pressure of about 500 kPa required in the conventional method can be set to about 390 kPa.
Therefore, power consumption can be greatly reduced. For example, energy saving of about 10% can be achieved as compared with the case of using a conventional air separation apparatus equipped with a double distillation column and an argon column.
Moreover, since the argon distillation column 7 is used, it is possible to collect argon.
[0025]
In the present invention, a part of the purified raw material air from the purifier 3 is secondarily compressed to about 400 kPa using the secondary compressor 14 by using the pipe L25 indicated by the broken line in FIG. It can also be introduced into the air condensing passage 51 through the passage L1.
In this case, the pressure of the raw material air in the air compressor 1 can be further reduced (for example, about 350 kPa). For this reason, power consumption can be further reduced.
In the present invention, the pressure of the product liquefied oxygen led out through the line L17 can be recovered by increasing the pressure by the booster pump 17.
[0026]
Next, a second embodiment of the air separation device of the present invention will be described.
FIG. 2 is a system diagram showing the air separation device of the present embodiment.
The air separation device 30 shown here is provided with an oxygen evaporator 31 for vaporizing product liquefied oxygen in a line L17 for deriving product liquefied oxygen, and an argon concentrate (product) obtained in the argon distillation column 7 1 is different from the air separation device 10 shown in FIG. 1 in that a high purity argon distillation column 34 for further distilling (Argon) is provided.
[0027]
The oxygen evaporator 31 can vaporize product liquefied oxygen by heat exchange with raw material air.
The high-pure argon distillation column 34 is a distillation column obtained by liquefying a part of the derived liquid from the distillation column 34 and a high-pure argon reboiler 34a that vaporizes a part of the derived liquid from the distillation column 34 and returns it to the distillation column 34. And a high-purity argon condenser 34b to be returned to 34.
The high purity argon condenser 34b can cool the derived gas by using a part of the nitrogen concentrate that has passed through the argon condenser 7b, the nitrogen condenser 6a, and the supercooler 11.
[0028]
Next, a second embodiment of the air separation method of the present invention will be described by taking the case of using this air separation device 30 as an example.
The raw material air is compressed by the air compressor 1 (for example, a pressure of about 390 kPa), cooled to room temperature by the air precooler 2, adsorbed and removed impurities by the purifier 3, cooled by the main heat exchanger 4, and piped It is introduced into the air condensing passage 51 of the heat exchange distillation apparatus 5 through the passage L1.
Part of the raw material air is introduced into the oxygen evaporator 31 through the line L31, where it is cooled by heat exchange with the product liquefied oxygen from the line L17, and then the nitrogen distillation tower through the lines L32, L3, and L4. 6 is introduced.
[0029]
The product liquefied oxygen led out from the lower part of the argon distillation column 7 through the line L17 is introduced into the oxygen evaporator 31, where it is vaporized by heat exchange with the raw material air, and then liquefied through the main heat exchanger 4. It is recovered as oxygen GO.
[0030]
In this air separation method, an argon concentrate (product argon GAr) led out from the upper part of the argon distillation column 7 through a pipe L20 is compressed by an argon compressor 32, and an oxygen purifier 33 is used to catalyze oxygen and the like. Remove with and purify.
Next, the purified argon concentrate is cooled by the main heat exchanger 4 and then introduced into the high purity argon reboiler 34a through the line L33.
In the high-purity argon reboiler 34a, the argon concentrate is cooled and liquefied by heat exchange with a liquid derived from the high-purity argon distillation column 34 (high-purity product argon described later), and then the line L34 and the pressure reducing valve V30 are connected. Then, it is introduced into the high purity argon distillation column 34.
[0031]
In the high purity argon distillation column 34, the introduced argon concentrate is distilled, the concentration of low-boiling components (such as nitrogen) in the gas phase is increased, and the argon concentration in the liquid phase is increased.
The low boiling point component-containing gas in the high purity argon distillation column 34 is led out through the pipes L37 and L41, led to the pipe L12, merged with the product low-pressure nitrogen, and recovered through the main heat exchanger 4. .
A part of the low boiling point component-containing gas is introduced into the high purity argon condenser 34b through the lines L37 and L38, and after the high boiling point component is liquefied, it is returned to the high purity argon distillation column 34 through the line L39.
[0032]
On the other hand, the high-concentration argon obtained in the high-purity argon distillation column 34 is led out from the lower part of the distillation column 34 through the pipe L40 and recovered as high-purity product argon PAr (for example, nitrogen 1 ppm or less, oxygen 0.1 ppm or less). Is done.
Part of the high-concentration argon (high-pure product argon) is introduced into the high-pure argon reboiler 34a through the pipe line L35 and is vaporized here, and then returned to the lower part of the distillation column 34 through the pipe line L36.
[0033]
In the present invention, the pressure of the product liquefied oxygen led out through the pipe L17 can be recovered by increasing the pressure by the booster pump 17 and evaporating the product liquefied oxygen by the oxygen evaporator 31.
[0034]
In the air separation method of the present embodiment, the heat exchange distillation apparatus 5, the nitrogen distillation tower 6, and the argon distillation tower 7 are used as in the method of the first embodiment. Therefore, the raw air and the nitrogen-enriched air are used. The heat exchange between the oxygen and the argon-containing crude oxygen can be efficiently performed, and the pressure of the raw material air can be set low.
Therefore, power consumption can be greatly reduced.
Moreover, since the argon distillation column 7 is used, it is possible to collect argon.
[0035]
【The invention's effect】
In the air separation method of the present invention, a heat exchange type distillation apparatus, a nitrogen distillation tower, and an argon distillation tower provided with an air condensation passage, a nitrogen distillation passage, and an oxygen distillation passage are used. Heat exchange between the chemical air and the argon-containing crude oxygen can be performed efficiently.
For this reason, the pressure of raw material air can be set low and power consumption can be reduced significantly.
Moreover, since an argon distillation column is used, it is possible to collect argon.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a first embodiment of an air separation device of the present invention.
FIG. 2 is a system diagram showing a second embodiment of the air separation device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air compressor, 4 ... Main heat exchanger, 5 ... Heat exchange type distillation apparatus, 6 ... Nitrogen distillation tower, 6a ... Nitrogen condenser, 7 ... Argon distillation tower 7a ... Argon reboiler, 7b ... Argon condenser, 8 ... Gas-liquid separator, 9 ... Expansion turbine, 10, 30 ... Air separation device, 13 ... Booster, 14. ..Secondary compressor, 17 ... booster pump, 31 ... oxygen evaporator, 51 ... air condensing passage, 52 ... nitrogen distillation passage, 53 ... oxygen distillation passage, RA ... Raw material air, MGN ... Product medium pressure nitrogen, GN ... Product low pressure nitrogen, GO ... Product liquefied oxygen, GAr ... Product argon

Claims (12)

空気を低温蒸留することにより、窒素、酸素、およびアルゴンを分離する空気分離方法において、
空気凝縮通路と、窒素蒸留通路と、これら通路と熱交換可能とされた酸素蒸留通路とを備えた熱交換型蒸留装置と、窒素蒸留塔と、アルゴン蒸留塔とを用い、
（１）原料空気を圧縮した後、この原料空気を、空気凝縮通路において、酸素蒸留通路との熱交換により冷却して部分液化させ、気相の窒素富化空気と液相の酸素アルゴン富化空気とを分離し、
（２）この窒素富化空気を、窒素蒸留通路において、酸素蒸留通路との熱交換により冷却しつつ蒸留して、窒素が濃縮された窒素濃縮物と、これより窒素濃度が低い窒素含有物とを分離し、窒素濃縮物を製品中圧窒素として回収し、
（３）この窒素含有物と前記酸素アルゴン富化空気を、窒素蒸留塔において蒸留し、窒素が濃縮された製品低圧窒素と、酸素およびアルゴンが濃縮されたアルゴン含有粗酸素とを分離し、製品低圧窒素を回収し、
（４）このアルゴン含有粗酸素を、酸素蒸留通路において、空気凝縮通路および窒素蒸留通路との熱交換により加熱しつつ蒸留し、酸素とアルゴンが濃縮されたアルゴン酸素原料を分離し、
（５）このアルゴン酸素原料を、アルゴン蒸留塔において蒸留し、アルゴンが濃縮された製品アルゴンと、酸素が濃縮された製品液化酸素とを分離し、これら製品アルゴンおよび製品液化酸素を回収することを特徴とする空気分離方法。In an air separation method for separating nitrogen, oxygen, and argon by low-temperature distillation of air,
Using an air condensing passage, a nitrogen distillation passage, a heat exchange type distillation apparatus having an oxygen distillation passage that can exchange heat with these passages, a nitrogen distillation tower, and an argon distillation tower,
(1) After compressing the feed air, the feed air is cooled in the air condensing passage by heat exchange with the oxygen distillation passage to be partially liquefied, and enriched in gaseous nitrogen and oxygen in the liquid phase Separate from the air,
(2) The nitrogen-enriched air is distilled while cooling in the nitrogen distillation passage by heat exchange with the oxygen distillation passage, and a nitrogen concentrate in which nitrogen is concentrated, and a nitrogen-containing material having a lower nitrogen concentration than this The nitrogen concentrate is recovered as medium-pressure nitrogen product,
(3) The nitrogen-containing material and the oxygen-argon-enriched air are distilled in a nitrogen distillation column to separate the product low-pressure nitrogen enriched with nitrogen and the argon-containing crude oxygen enriched with oxygen and argon, Recover low pressure nitrogen,
(4) The argon-containing crude oxygen is distilled while being heated by heat exchange with the air condensing passage and the nitrogen distillation passage in the oxygen distillation passage to separate the argon oxygen raw material in which oxygen and argon are concentrated,
(5) The argon oxygen raw material is distilled in an argon distillation column, and product argon enriched with argon is separated from product liquefied oxygen enriched with oxygen, and the product argon and product liquefied oxygen are recovered. A featured air separation method. アルゴン蒸留塔が、この蒸留塔からの導出液の一部を気化させてこの蒸留塔に戻すアルゴンリボイラと、この蒸留塔からの導出ガスの一部を液化させてこの蒸留塔に戻すアルゴンコンデンサを備え、
窒素蒸留塔が、この蒸留塔内の窒素を気化させる窒素凝縮器を備え、
窒素蒸留通路からの窒素濃縮物の一部を、アルゴンリボイラに加熱源として導入し、次いでアルゴンコンデンサに冷却源として導入し、次いで窒素凝縮器に加熱源として導入し、次いで窒素蒸留塔に導入することを特徴とする請求項１記載の空気分離方法。The argon distillation tower has an argon reboiler that vaporizes a part of the liquid discharged from the distillation column and returns it to the distillation tower, and an argon condenser that liquefies a part of the gas discharged from the distillation tower and returns the liquid to the distillation column. Prepared,
The nitrogen distillation column includes a nitrogen condenser for vaporizing nitrogen in the distillation column,
Part of the nitrogen concentrate from the nitrogen distillation passage is introduced into the argon reboiler as a heating source, then into the argon condenser as a cooling source, then into the nitrogen condenser as a heating source and then into the nitrogen distillation column The air separation method according to claim 1. 圧縮した原料空気の一部をさらに圧縮し、得られた二次圧縮原料空気を、前記製品により冷却した後、空気凝縮通路に供給することを特徴とする請求項１記載の空気分離方法。2. The air separation method according to claim 1, wherein a part of the compressed raw material air is further compressed, and the obtained secondary compressed raw material air is cooled by the product and then supplied to the air condensing passage. 製品液化酸素を、原料空気との熱交換により気化させることを特徴とする請求項１記載の空気分離方法。2. The air separation method according to claim 1, wherein product liquefied oxygen is vaporized by heat exchange with raw material air. 製品液化酸素を、昇圧した後に回収することを特徴とする請求項４記載の空気分離方法。The air separation method according to claim 4, wherein the product liquefied oxygen is recovered after being pressurized. 窒素蒸留通路によって分離された窒素濃縮物の一部を圧縮した後、断熱膨張させ、この断熱膨張時に得られる動力を利用して前記窒素濃縮物の圧縮を行うことを特徴とする請求項１記載の空気分離方法。2. A portion of the nitrogen concentrate separated by the nitrogen distillation passage is compressed and then adiabatically expanded, and the nitrogen concentrate is compressed using power obtained during the adiabatic expansion. Air separation method. 空気を低温蒸留することにより、窒素、酸素、およびアルゴンを分離する空気分離装置において、
原料空気を圧縮する空気圧縮機と、圧縮された原料空気を冷却する主熱交換器と、冷却された原料空気を蒸留する熱交換型蒸留装置と、熱交換型蒸留装置を経た蒸留物をさらに蒸留する窒素蒸留塔と、窒素蒸留塔を経た蒸留物をさらに蒸留するアルゴン蒸留塔とを備え、
熱交換型蒸留装置が、空気凝縮通路と、窒素蒸留通路と、これら通路と熱交換可能とされた酸素蒸留通路とを備え、
空気凝縮通路が、原料空気を、酸素蒸留通路との熱交換により冷却して部分液化させ、気相の窒素富化空気と液相の酸素アルゴン富化空気とを得ることができるようにされ、
窒素蒸留通路が、この窒素富化空気を、酸素蒸留通路との熱交換により冷却しつつ蒸留し、窒素が濃縮された窒素濃縮物である製品中圧窒素と、これより窒素濃度が低い窒素含有物とを得ることができるようにされ、
窒素蒸留塔が、この窒素含有物と前記酸素アルゴン富化空気を蒸留して、窒素が濃縮された製品低圧窒素と、酸素およびアルゴンが濃縮されたアルゴン含有粗酸素とを得ることができるようにされ、
酸素蒸留通路が、このアルゴン含有粗酸素を、空気凝縮通路および窒素蒸留通路との熱交換により加熱しつつ蒸留し、酸素およびアルゴンが濃縮されたアルゴン酸素原料を得ることができるようにされ、
アルゴン蒸留塔が、このアルゴン酸素原料を蒸留し、アルゴンが濃縮された製品アルゴンと、酸素が濃縮された製品液化酸素とを得ることができるようにされていることを特徴とする空気分離装置。In an air separation device that separates nitrogen, oxygen, and argon by low-temperature distillation of air,
An air compressor that compresses the raw material air, a main heat exchanger that cools the compressed raw material air, a heat exchange distillation device that distills the cooled raw material air, and a distillate that has passed through the heat exchange distillation device A nitrogen distillation column for distillation, and an argon distillation column for further distilling the distillate that has passed through the nitrogen distillation column;
A heat exchange type distillation apparatus includes an air condensing passage, a nitrogen distillation passage, and an oxygen distillation passage capable of exchanging heat with these passages.
The air condensing passage is cooled by heat exchange with the oxygen distillation passage to be partially liquefied to obtain gas-phase nitrogen-enriched air and liquid-phase oxygen-argon-enriched air,
The nitrogen distillation passage distills while cooling this nitrogen-enriched air by heat exchange with the oxygen distillation passage, and the product medium-pressure nitrogen, which is a nitrogen concentrate enriched with nitrogen, and nitrogen containing a lower nitrogen concentration than this Being able to get things and
A nitrogen distillation column can distill the nitrogen-containing material and the oxygen-argon enriched air to obtain a low-pressure nitrogen product enriched with nitrogen and a crude oxygen-containing oxygen enriched with oxygen and argon. And
The oxygen distillation passage is made to distill while heating this argon-containing crude oxygen by heat exchange with the air condensing passage and the nitrogen distillation passage to obtain an oxygen-oxygen raw material enriched with oxygen and argon,
An air separation device characterized in that an argon distillation column can distill the argon oxygen raw material to obtain product argon enriched with argon and product liquefied oxygen enriched with oxygen. アルゴン蒸留塔が、この蒸留塔からの導出液の一部を気化させてこの蒸留塔に戻すアルゴンリボイラと、この蒸留塔からの導出ガスの一部を液化させてこの蒸留塔に戻すアルゴンコンデンサを備え、
窒素蒸留塔が、この蒸留塔内の窒素を気化させる窒素凝縮器を備え、
窒素蒸留通路からの窒素濃縮物の一部を、アルゴンリボイラに加熱源として導入し、次いでアルゴンコンデンサに冷却源として導入し、次いで窒素凝縮器に加熱源として導入し、次いで窒素蒸留塔に導入することができるように構成されていることを特徴とする請求項７記載の空気分離措置。The argon distillation tower has an argon reboiler that vaporizes a part of the liquid discharged from the distillation column and returns it to the distillation tower, and an argon condenser that liquefies a part of the gas discharged from the distillation tower and returns the liquid to the distillation column. Prepared,
The nitrogen distillation column includes a nitrogen condenser for vaporizing nitrogen in the distillation column,
Part of the nitrogen concentrate from the nitrogen distillation passage is introduced into the argon reboiler as a heating source, then into the argon condenser as a cooling source, then into the nitrogen condenser as a heating source and then into the nitrogen distillation column The air separation device according to claim 7, wherein the air separation device is configured to be able to perform the operation. 空気圧縮機で圧縮された原料空気の一部をさらに圧縮する二次圧縮機を備え、
この圧縮機によって圧縮された二次圧縮原料空気を、主熱交換器を経て空気凝縮通路に供給することができるようになっていることを特徴とする請求項７記載の空気分離装置。A secondary compressor that further compresses a part of the raw material air compressed by the air compressor,
The air separation device according to claim 7, wherein the secondary compressed raw material air compressed by the compressor can be supplied to the air condensing passage through the main heat exchanger. 製品液化酸素を気化させる酸素蒸発器を備え、この酸素蒸発器が、原料空気との熱交換によって製品液化酸素を気化させることができるようにされていることを特徴とする請求項７記載の空気分離装置。8. An air according to claim 7, further comprising an oxygen evaporator for vaporizing product liquefied oxygen, wherein the oxygen evaporator is capable of vaporizing product liquefied oxygen by heat exchange with raw material air. Separation device. 製品液化酸素を昇圧する昇圧ポンプを備えていることを特徴とする請求項１０記載の空気分離装置。The air separation device according to claim 10, further comprising a booster pump that pressurizes product liquefied oxygen. 酸素蒸発器を経た原料空気を窒素蒸留塔に導入することができるようになっていることを特徴とする請求項１０記載の空気分離装置。The air separation device according to claim 10, wherein the raw material air having passed through the oxygen evaporator can be introduced into a nitrogen distillation column.
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