JP2004020161A - High-purity nitrogen gas manufacturing device - Google Patents

High-purity nitrogen gas manufacturing device Download PDF

Info

Publication number
JP2004020161A
JP2004020161A JP2002180225A JP2002180225A JP2004020161A JP 2004020161 A JP2004020161 A JP 2004020161A JP 2002180225 A JP2002180225 A JP 2002180225A JP 2002180225 A JP2002180225 A JP 2002180225A JP 2004020161 A JP2004020161 A JP 2004020161A
Authority
JP
Japan
Prior art keywords
liquid
air
heat exchanger
nitrogen
liquid air
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.)
Pending
Application number
JP2002180225A
Other languages
Japanese (ja)
Inventor
Akira Yoshino
吉野　明
Atsushi Miyamoto
宮本　篤
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 Water Inc
Original Assignee
Air Water Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Air Water Inc filed Critical Air Water Inc
Priority to JP2002180225A priority Critical patent/JP2004020161A/en
Publication of JP2004020161A publication Critical patent/JP2004020161A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—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
    • F25J3/042—Division of the main heat exchange line in consecutive sections having different functions having an intermediate feed connection
    • 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
    • F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
    • 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
    • F25J3/04254—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using the cold stored in external cryogenic fluids
    • 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
    • F25J3/044—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 single pressure main column system 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
    • F25J3/04763—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
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04854—Safety aspects of operation
    • F25J3/0486—Safety aspects of operation of vaporisers for oxygen enriched liquids, e.g. purging of liquids
    • 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
    • F25J2200/72—Refluxing the column with at least a part of the totally condensed overhead gas
    • 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
    • F25J2250/42—One fluid being nitrogen

Landscapes

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

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-purity nitrogen gas manufacturing device miniaturizing the device whole body, simplifying the structure of the device whole body, and manufacturing the high-purity gas at low cost in such a way as reducing the equipment cost and the usage of cold liquid nitrogen. <P>SOLUTION: This high-purity nitrogen gas manufacturing device is provided with an air compressor 1, a main heat exchanger 5 cooling compressed air compressed by the air compressor 1, a rectifying column 7, a condenser 18 provided in the upper part of the rectifying column 7, a liquid air sump 17 for manufacturing circulating liquid in the condenser 18, a pipe feeding the liquid air 8 in the bottom part of the rectifying column 7 to the liquid air sump 17, and a guide pipe 30 introducing the liquid air 9 in the liquid air sump 17 to an intermediate part of the main heat exchanger 5, exchanging its heat, vaporizing it, and releasing it to the outside. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、高純度窒素ガス製造装置に関するものである。
【０００２】
【従来の技術】
従来の窒素ガスの製造装置は、例えば、図２に示すように、空気圧縮機（図示せず）で圧縮された圧縮空気を吸着手段（図示せず）で水分と炭酸ガスとを除去し、主熱交換器５０に通して超低温に冷却したのち精留塔５１に導入し、この精留塔５１において、深冷液化分離により、低沸点の窒素を気体として保持するとともに、残部を酸素リッチな液体空気５６として溜め、上記精留塔５１から取り出した窒素ガスを主熱交換器５０に通して温度上昇させたのち製品窒素ガスとして取り出している。また、上記精留塔５１の上部から取り出した窒素ガスの一部を精留塔５１の上方に配設した凝縮器５２に送り、ここで液化して精留塔５１の上部に還流させる。一方、上記凝縮器５２の冷却用として、精留塔５１の底部に溜まる液体空気５６を膨脹弁５４ａ付きパイプ５４を介して液体空気溜め５３に供給している。そして、液体空気溜め５３に溜まる液体空気５７中に炭化水素や一酸化炭素等が濃縮するのを防止するため、液体空気５７を液体空気溜め５３の底部から取り出して専用の熱交換器５５に送り込み、空気圧縮機で圧縮された圧縮空気の一部と熱交換して気化させたのち大気に放出している。図において、５８は第１の還流液パイプで、５９は第２の還流液パイプで、６０は液体空気溜め５３の上部に溜ったガスを排窒素ガスとして放出する放出パイプであり、６１は液体窒素を貯蔵する液体窒素貯槽であり、装置外から液体窒素の供給を受けている。
【０００３】
【発明が解決しようとする課題】
しかしながら、上記の装置では、液体空気溜め５３の底部に溜まる液体空気５７を熱交換して気化させるために専用の熱交換器５５を設けており、スペースをとって装置全体が大形化したり、装置全体の構造が複雑化したりするという問題や、設備費が高価になるという問題がある。また、液体空気溜め５３に溜まる液体空気５７を大気温度近くまで加温するため、専用の熱交換器５５に圧縮空気の一部を理論量より過剰に加えることになり、そのため、主熱交換器５０に供給される圧縮空気が減少し、熱交換ロスが増大するという問題がある。
【０００４】
本発明は、このような事情に鑑みなされたもので、装置全体を小形化したり、装置全体の構造を簡単化したりすることができ、しかも、設備費や寒冷用の液化窒素の使用量が減少する等安価に高純度窒素ガスを製造することのできる高純度窒素ガス製造装置の提供をその目的とする。
【０００５】
【課題を解決するための手段】
上記の目的を達成するため、本発明の高純度窒素ガス製造装置は、外部より取り入れた空気を圧縮する空気圧縮手段と、この空気圧縮手段により圧縮された圧縮空気を冷却する熱交換器と、この熱交換器を経由し超低温に冷却された圧縮空気の一部を液化して内部に溜め窒素を気体として保持する精留塔と、この精留塔の上部に設けられた凝縮器と、上記凝縮器で還流液を製造するための液体空気溜めと、上記精留塔の底部の貯溜液体空気を上記液体空気溜めに送給する供給路とを備え、上記液体空気溜めに送給した液体空気の一部を上記熱交換器の中間部に導入して熱交換させ気化させたのち外部へ放出する放出路を設けたという構成をとる。
【０００６】
すなわち、本発明者らは、液体空気（略−１８１℃）の熱交換を、専用の熱交換器を用いて行うのではなく、主熱交換器を利用して行う場合に、主熱交換器の圧縮空気出口側（略−１７６℃）から液体空気を導入すると、最も効率よく冷熱を回収することができ、寒冷用の液化窒素の使用量は最小となるのであるが、このとき、液化窒素が徐々に蒸発し、その結果、主熱交換器にメタン（沸点−１６４℃）が濃縮し、液体空気中の酸素と反応して爆発するおそれがある。ところが、主熱交換器の中間部で、温度がメタンの沸点である−１６４℃以上の場所（より効果が発揮されるのは、熱歪等の影響のでない−１１０〜−１４０℃の、液体空気との温度差が４０〜７０℃程度である場所）に液体空気を導入すると、導入と同時に液体空気が主熱交換器内で急激に沸騰が生じ、メタンが濃縮しないことを見いだし、本発明に到達した。
【０００７】
本発明において、液体窒素貯蔵手段と、この液体窒素貯蔵手段内の液体窒素を圧縮空気液化用の寒冷源として上記精留塔内に導く導入路とを備えている場合には、装置外から供給される液体窒素を液体窒素貯蔵手段に貯留することにより、装置外から供給される液体窒素を利用することができる。
【０００８】
【発明の実施の形態】
つぎに、本発明の実施の形態を図面にもとづいて詳しく説明する。
【０００９】
図１は本発明の高純度窒素ガス製造装置の一実施の形態を示している。図において、１は空気圧縮機、２はドライヤー、３，４は２個１組の吸着塔である。５はプレートフィン型の主熱交換器であり、上記吸着塔３，４により水分および炭酸ガスが吸着除去された圧縮空気が、圧縮空気供給パイプ６を経て送り込まれ、熱交換作用により超低温に冷却される。この主熱交換器５の圧縮空気出口側の温度は略−１７６℃で、圧縮空気入口側の温度は略＋１０℃程度である。７は精留塔であり、主熱交換器５により超低温に冷却され圧縮空気供給パイプ６を経て送り込まれる圧縮空気をさらに冷却し、その一部を液化し液体空気８として底部に溜め、窒素を気体状態で上部に保持するようにしている。この精留塔７には、その上方位置に、液体窒素貯槽１１（この液体窒素貯槽１１は、装置外から液体窒素の供給を受けている）から液体窒素が液体窒素導入パイプ１２を介して送り込まれる。また、精留塔７内では、圧縮空気中の高沸点成分（酸素分）が液化されて精留塔７の底部に溜り、低沸点成分の窒素ガスが精留塔７の上部に溜る。
【００１０】
１５は精留塔７の上部に溜った窒素ガスを製品窒素ガスとして取り出す取出パイプで、超低温の窒素ガスを主熱交換器５内に案内し、そこに送り込まれる圧縮空気と熱交換させて常温にしメインパイプ１６に送り込む作用をする。１７は凝縮器１８を収納した液体空気溜めで、上記凝縮器１８に、精留塔７の上部に溜る窒素ガスの一部が第１の還流液パイプ１３を介して送り込まれて液化し、第２の還流液パイプ１４を経て上記精留塔７の上部に還流するようになっている。上記液体空気溜め１７内は、精留塔７内よりも減圧状態になっており、精留塔７の底部の貯留液体空気８が膨脹弁１９付きパイプ２０を経て送り込まれ、気化して液体空気溜め１７の内部温度を液体窒素の沸点以下の温度に冷却するようにしている。この冷却により、精留塔７から第１の還流液パイプ１３を介して凝縮器１８内に送り込まれた窒素ガスが液化し、上記のように第２の還流液パイプ１４を介して精留塔７の上部に還流する。
【００１１】
２２は第１の液面指示調節計であり、精留塔７内の液体空気８の液面を所定レベルに保つようにその液面に応じて弁２３を制御し、液体窒素貯槽１１からの液体窒素の流量を制御する。２４は第２の液面指示調節計であり、液体空気溜め１７内の液体空気９（略−１８１℃）の液面を一定レベルに保つようにその液面に応じて膨脹弁１９を制御し、精留塔７内の液体空気８の気化量を制御する。２５はバックアップ系ラインであり、本装置が故障したり、製品窒素ガスが不足したりしたときに弁２６を開き、液体窒素貯槽１１内の液体窒素を蒸発器２７により蒸発させてメインパイプ１６に送り込み、窒素ガスの供給がとだえることのないようにしている。
【００１２】
３０は液体空気溜め１７内の液体空気９中の炭化水素や二酸化炭素等の濃縮を防止するために液体空気９を主熱交換器５の中間部（−１１０〜−１４０℃）に案内する案内パイプであり、この案内パイプ３０により主熱交換器５の中間部に導入された液体空気９は、主熱交換器５に送り込まれた圧縮空気と熱交換したのち、放出パイプ３１により大気に放出される。そして、上記導入時に、液体空気９と主熱交換器５の中間部との温度差により、液体空気９は主熱交換器５内で急激に沸騰するため、主熱交換器５にメタンが濃縮しない。３２は液体空気溜め１７の上部に溜ったガスを排窒素ガスとして取り出す排窒素ガス取出パイプであり、排窒素ガスを主熱交換器５に案内してその冷熱により圧縮空気を超低温に冷却し、続いてその一部を放出パイプ３３から直接大気中に放出する。３４は加圧器であり、液体窒素貯槽１１内の液体窒素の使用により、液体窒素貯槽１１内の上部ガス空間の圧力が低下しないよう、液体窒素貯槽１１内の液体窒素の一部を蒸発させて上記上部ガス空間に送るようにしている。３５は供給弁であり、この供給弁３５を作動させて製品窒素ガスを送る。図において、３６は放出パイプ３３の先端から分岐した分岐パイプであり、放出パイプ３３内の排窒素ガスの他部を吸着剤の再生工程に送る。
【００１３】
この装置は、つぎのようにして製品窒素ガスを製造する。すなわち、空気圧縮機１により空気を圧縮し、この圧縮された空気をドライヤー２により空気中の水分を除去し、その状態で吸着塔３（４）に送り込み水分および炭酸ガスを吸着除去する。ついで、水分および炭酸ガスが吸着除去された圧縮空気を、圧縮空気供給パイプ６を経由させ主熱交換器５内に送り込んで超低温に冷却し、圧縮空気供給パイプ６を経て精留塔７の下部内に投入する。ついで、この投入圧縮空気を、液体窒素貯槽１１から液体窒素導入パイプ１２を経由して精留塔７内に寒冷源として送り込まれた液体窒素、および凝縮器１８を経由して精留塔７の上部に戻される還流液と向流的に接触させて冷却し、その一部を液化して精留塔７の底部に液体空気８として溜める。この液体空気８を膨脹弁１９付きパイプ２０を介して液体空気溜め１７内に送り込み凝縮器１８を冷却させる。この冷却により、精留塔７の上部から凝縮器１８に送り込まれた窒素ガスが液化し、還流液となり第２の還流液パイプ１４を経て精留塔７の上部に戻る。そして、上記のように精留塔７内において、投入された圧縮空気と液体窒素，還流液とを接触させて冷却する過程において、窒素と酸素との沸点の差（酸素の沸点−１８３℃，窒素の沸点−１９６℃）により、圧縮空気中の高沸点成分である酸素が液化して流下し、窒素が気体のまま精留塔７の上部に残る。ついで、上記気体のまま残った窒素ガスを取出パイプ１５から取り出して主熱交換器５に送り込み、常温近くまで昇温させメインパイプ１６から超高純度の製品窒素ガスとして送り出す。また、液体空気溜め１７内の液体空気９は、案内パイプ３０で主熱交換器５の中間部に案内されると、液体空気９と主熱交換器５の中間部との温度差により主熱交換器５内で急激に沸騰し、主熱交換器５にメタンが濃縮しない。
【００１４】
このように、上記実施の形態では、液体空気溜め１７内の液体空気９を主熱交換器５の中間部に案内することにより、従来例の専用の熱交換器５５を用いる必要がなくなり、装置全体を小形化し、かつ、装置全体の構造を簡単化することができる。また、設備費を安価にすることもできる。また、上記専用の熱交換器５５に圧縮空気の一部を供給する必要がなく、熱交換ロスの増大が防止される。
【００１５】
なお、上記実施の形態では、液体空気溜め１７の内部に凝縮器１８を収納しているが、これに限定するものではなく、液体空気溜め１７の外部に凝縮器１８を設けるようにしてもよい。
【００１６】
【発明の効果】
以上のように、本発明の高純度窒素ガス製造装置によれば、熱交換器の中間部に液体空気溜め内の液体空気を導入しているため、従来例の専用の熱交換器５５を用いる必要がなくなり、装置全体を小形化したり、装置全体の構造を簡単化したりすることができる。しかも、設備費が安価である。また、上記専用の熱交換器５５に圧縮空気の一部を供給する必要がないため、熱交換器での熱交換ロスが防がれる。
【００１７】
本発明において、液体窒素貯蔵手段と、この液体窒素貯蔵手段内の液体窒素を圧縮空気液化用の寒冷源として上記精留塔内に導く導入路とを備えている場合には、装置外から供給される液体窒素を液体窒素貯蔵手段に貯留することにより、装置外から供給される液体窒素を利用することができる。
【図面の簡単な説明】
【図１】本発明の高純度窒素ガス製造装置の一実施の形態を示す構成図である。
【図２】従来例の要部の構成図である。
【符号の説明】
１　空気圧縮機
５　主熱交換器
７　精留塔
８，９　液体空気
１７　液体空気溜め
１８　凝縮器
２０　パイプ
３０　案内パイプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for producing high-purity nitrogen gas.
[0002]
[Prior art]
For example, as shown in FIG. 2, a conventional nitrogen gas producing apparatus removes moisture and carbon dioxide gas by compressed air compressed by an air compressor (not shown) by an adsorption means (not shown). After passing through the main heat exchanger 50 and cooled to an extremely low temperature, the mixture is introduced into a rectification column 51. In the rectification column 51, low-boiling nitrogen is retained as a gas by cryogenic liquefaction separation, and the remainder is oxygen-rich. It is stored as liquid air 56, and the nitrogen gas taken out from the rectification column 51 is passed through the main heat exchanger 50 to raise the temperature and then taken out as product nitrogen gas. Further, a part of the nitrogen gas taken out from the upper part of the rectification column 51 is sent to a condenser 52 disposed above the rectification column 51, where it is liquefied and refluxed to the upper part of the rectification column 51. On the other hand, for cooling the condenser 52, liquid air 56 stored at the bottom of the rectification column 51 is supplied to a liquid air reservoir 53 via a pipe 54 with an expansion valve 54a. Then, in order to prevent hydrocarbons, carbon monoxide and the like from being concentrated in the liquid air 57 stored in the liquid air reservoir 53, the liquid air 57 is taken out from the bottom of the liquid air reservoir 53 and sent to a dedicated heat exchanger 55. The heat is exchanged with a part of the compressed air compressed by an air compressor to vaporize the gas and then released to the atmosphere. In the figure, 58 is a first reflux liquid pipe, 59 is a second reflux liquid pipe, 60 is a discharge pipe for discharging gas accumulated in the upper part of the liquid air reservoir 53 as nitrogen gas, and 61 is a liquid pipe. This is a liquid nitrogen storage tank for storing nitrogen, and is supplied with liquid nitrogen from outside the apparatus.
[0003]
[Problems to be solved by the invention]
However, in the above-described device, a dedicated heat exchanger 55 is provided for exchanging heat and evaporating the liquid air 57 stored in the bottom of the liquid air reservoir 53, so that the entire device takes up space, There is a problem that the structure of the whole apparatus becomes complicated and a problem that equipment cost becomes expensive. In addition, in order to heat the liquid air 57 stored in the liquid air reservoir 53 to near the atmospheric temperature, a part of the compressed air is added to the dedicated heat exchanger 55 in excess of the theoretical amount, so that the main heat exchanger There is a problem in that the amount of compressed air supplied to the fuel cell 50 decreases and the heat exchange loss increases.
[0004]
The present invention has been made in view of such circumstances, and can reduce the size of the entire apparatus and simplify the structure of the entire apparatus, and reduce the equipment cost and the amount of liquefied nitrogen used for cooling. It is an object of the present invention to provide a high-purity nitrogen gas producing apparatus capable of producing high-purity nitrogen gas at low cost.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the high-purity nitrogen gas producing apparatus of the present invention includes an air compression unit that compresses air taken in from outside, a heat exchanger that cools compressed air compressed by the air compression unit, A rectification tower that liquefies a part of the compressed air cooled to an extremely low temperature via this heat exchanger and stores the liquefied air inside to retain nitrogen as a gas; a condenser provided at the top of the rectification tower; A liquid air reservoir for producing a reflux liquid in a condenser; and a supply passage for supplying the stored liquid air at the bottom of the rectification column to the liquid air reservoir, wherein the liquid air supplied to the liquid air reservoir is provided. Is introduced into an intermediate portion of the heat exchanger, heat is exchanged and vaporized, and then a discharge path for releasing the gas to the outside is provided.
[0006]
That is, when the present inventors perform heat exchange of liquid air (approximately -181 ° C) using a main heat exchanger instead of using a dedicated heat exchanger, the main heat exchanger is used. When the liquid air is introduced from the compressed air outlet side (approximately -176 ° C.), the cold energy can be recovered most efficiently, and the amount of liquefied nitrogen used for cooling is minimized. Gradually evaporates, and as a result, methane (boiling point -164 ° C.) is concentrated in the main heat exchanger and may react with oxygen in liquid air to explode. However, in the middle part of the main heat exchanger, a place where the temperature is equal to or higher than the boiling point of methane, −164 ° C. When the liquid air is introduced into a place where the temperature difference with the air is about 40 to 70 ° C.), it is found that the liquid air is rapidly boiled in the main heat exchanger at the same time as the introduction, and methane is not concentrated. Reached.
[0007]
In the present invention, when a liquid nitrogen storage means and an introduction path for introducing liquid nitrogen in the liquid nitrogen storage means into the rectification column as a cold source for liquefying compressed air are provided from outside the apparatus. By storing the liquid nitrogen to be stored in the liquid nitrogen storage means, liquid nitrogen supplied from outside the apparatus can be used.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0009]
FIG. 1 shows an embodiment of the high-purity nitrogen gas producing apparatus of the present invention. In the figure, 1 is an air compressor, 2 is a dryer, and 3 and 4 are a pair of two adsorption towers. Reference numeral 5 denotes a plate-fin type main heat exchanger. The compressed air from which moisture and carbon dioxide are adsorbed and removed by the adsorption towers 3 and 4 is sent through a compressed air supply pipe 6 and cooled to an extremely low temperature by a heat exchange action. Is done. The temperature at the compressed air outlet side of the main heat exchanger 5 is approximately -176 ° C, and the temperature at the compressed air inlet side is approximately + 10 ° C. Reference numeral 7 denotes a rectification column, which further cools the compressed air cooled to an extremely low temperature by the main heat exchanger 5 and sent through the compressed air supply pipe 6, liquefies part of the liquefied air and collects it at the bottom as liquid air 8 to store nitrogen. It is kept in a gaseous state at the top. Liquid nitrogen is fed into the rectification column 7 from a liquid nitrogen storage tank 11 (the liquid nitrogen storage tank 11 receives a supply of liquid nitrogen from outside the apparatus) via a liquid nitrogen introduction pipe 12 at a position above the rectification tower 7. It is. In the rectification column 7, the high-boiling component (oxygen component) in the compressed air is liquefied and accumulates at the bottom of the rectification column 7, and the nitrogen gas of the low-boiling component accumulates at the top of the rectification column 7.
[0010]
Reference numeral 15 denotes an extraction pipe for extracting nitrogen gas collected at the upper part of the rectification column 7 as product nitrogen gas. The extraction pipe 15 guides ultra-low temperature nitrogen gas into the main heat exchanger 5 and exchanges heat with the compressed air sent therein to normal temperature. Then, it works to feed into the main pipe 16. Reference numeral 17 denotes a liquid air reservoir containing a condenser 18. A part of the nitrogen gas stored in the upper part of the rectification column 7 is fed into the condenser 18 through the first reflux liquid pipe 13 and liquefied. The liquid is refluxed to the upper part of the rectification column 7 through the second reflux liquid pipe 14. The pressure in the liquid air reservoir 17 is lower than that in the rectification tower 7, and the stored liquid air 8 at the bottom of the rectification tower 7 is sent through a pipe 20 with an expansion valve 19, and is vaporized to be liquid air The internal temperature of the reservoir 17 is cooled to a temperature lower than the boiling point of liquid nitrogen. By this cooling, the nitrogen gas sent from the rectification tower 7 into the condenser 18 via the first reflux liquid pipe 13 is liquefied, and as described above, the rectification tower is supplied via the second reflux liquid pipe 14. Reflux to the top of 7.
[0011]
Reference numeral 22 denotes a first liquid level indicating controller, which controls a valve 23 according to the liquid level of the liquid air 8 in the rectification column 7 so as to maintain the liquid level at a predetermined level. Control the flow rate of liquid nitrogen. Reference numeral 24 denotes a second liquid level indicating controller, which controls the expansion valve 19 in accordance with the liquid level so that the liquid level of the liquid air 9 (about -181 ° C.) in the liquid air reservoir 17 is maintained at a constant level. And the amount of liquid air 8 vaporized in the rectification column 7 is controlled. Reference numeral 25 denotes a backup system line, which opens the valve 26 when the apparatus breaks down or the product nitrogen gas runs short, and evaporates the liquid nitrogen in the liquid nitrogen storage tank 11 by the evaporator 27 to the main pipe 16. The supply and supply of nitrogen gas are not interrupted.
[0012]
A guide 30 guides the liquid air 9 to an intermediate portion (−110 to −140 ° C.) of the main heat exchanger 5 in order to prevent concentration of hydrocarbons, carbon dioxide, and the like in the liquid air 9 in the liquid air reservoir 17. The liquid air 9 introduced into the intermediate portion of the main heat exchanger 5 by the guide pipe 30 exchanges heat with the compressed air sent to the main heat exchanger 5 and then discharged to the atmosphere by the discharge pipe 31. Is done. At the time of the introduction, the liquid air 9 is rapidly boiled in the main heat exchanger 5 due to a temperature difference between the liquid air 9 and an intermediate portion of the main heat exchanger 5, so that methane is concentrated in the main heat exchanger 5. do not do. Reference numeral 32 denotes an exhaust nitrogen gas extraction pipe for extracting the gas accumulated in the upper part of the liquid air reservoir 17 as exhaust nitrogen gas, and guides the exhaust nitrogen gas to the main heat exchanger 5 to cool the compressed air to an extremely low temperature by the cold heat thereof. Subsequently, a part thereof is discharged directly from the discharge pipe 33 into the atmosphere. Reference numeral 34 denotes a pressurizer which evaporates a part of the liquid nitrogen in the liquid nitrogen storage tank 11 so that the pressure in the upper gas space in the liquid nitrogen storage tank 11 does not decrease due to the use of the liquid nitrogen in the liquid nitrogen storage tank 11. The gas is sent to the upper gas space. A supply valve 35 operates the supply valve 35 to send product nitrogen gas. In the figure, reference numeral 36 denotes a branch pipe branched from the tip of the discharge pipe 33, which sends the other part of the exhaust gas in the discharge pipe 33 to the adsorbent regeneration step.
[0013]
This device produces product nitrogen gas as follows. That is, the air is compressed by the air compressor 1, and the compressed air is used to remove the moisture in the air by the dryer 2, and then sent to the adsorption tower 3 (4) in that state to adsorb and remove the moisture and carbon dioxide gas. Then, the compressed air from which water and carbon dioxide have been adsorbed and removed is sent into the main heat exchanger 5 via a compressed air supply pipe 6 and cooled to an extremely low temperature. Put in. Next, the input compressed air is supplied from the liquid nitrogen storage tank 11 through the liquid nitrogen introduction pipe 12 into the rectification tower 7 via the liquid nitrogen as a cold source, and through the condenser 18 into the rectification tower 7. The reflux liquid returned to the upper part is brought into contact with the reflux liquid countercurrently and cooled, and a part thereof is liquefied and stored as liquid air 8 at the bottom of the rectification column 7. The liquid air 8 is sent into a liquid air reservoir 17 through a pipe 20 with an expansion valve 19 to cool the condenser 18. By this cooling, the nitrogen gas sent into the condenser 18 from the upper part of the rectification tower 7 is liquefied, becomes a reflux liquid, and returns to the upper part of the rectification tower 7 via the second reflux liquid pipe 14. Then, as described above, in the rectification column 7, in the process of bringing the compressed air and the liquid nitrogen and the reflux liquid into contact with each other and cooling the mixture, the difference in boiling point between nitrogen and oxygen (the boiling point of oxygen is −183 ° C., Oxygen, which is a high-boiling component in the compressed air, liquefies and flows down due to the boiling point of nitrogen (−196 ° C.), and nitrogen remains in the upper part of the rectification column 7 as a gas. Then, the nitrogen gas remaining as it is is taken out from the extraction pipe 15 and sent to the main heat exchanger 5, where it is heated to near normal temperature and sent out from the main pipe 16 as ultra-high purity product nitrogen gas. When the liquid air 9 in the liquid air reservoir 17 is guided to an intermediate portion of the main heat exchanger 5 by the guide pipe 30, the main heat is generated due to a temperature difference between the liquid air 9 and the intermediate portion of the main heat exchanger 5. Boiling rapidly in the exchanger 5, and methane is not concentrated in the main heat exchanger 5.
[0014]
As described above, in the above embodiment, the liquid air 9 in the liquid air reservoir 17 is guided to the intermediate portion of the main heat exchanger 5, so that it is not necessary to use the dedicated heat exchanger 55 of the conventional example, and the apparatus The overall size can be reduced, and the structure of the entire device can be simplified. Also, equipment costs can be reduced. Further, it is not necessary to supply a part of the compressed air to the dedicated heat exchanger 55, so that an increase in heat exchange loss is prevented.
[0015]
In the above-described embodiment, the condenser 18 is housed inside the liquid air reservoir 17. However, the present invention is not limited to this, and the condenser 18 may be provided outside the liquid air reservoir 17. .
[0016]
【The invention's effect】
As described above, according to the high-purity nitrogen gas producing apparatus of the present invention, since the liquid air in the liquid air reservoir is introduced into the intermediate part of the heat exchanger, the conventional dedicated heat exchanger 55 is used. This eliminates the necessity, and makes it possible to reduce the size of the entire device or simplify the structure of the entire device. Moreover, the equipment cost is low. Further, since it is not necessary to supply a part of the compressed air to the dedicated heat exchanger 55, heat exchange loss in the heat exchanger is prevented.
[0017]
In the present invention, when a liquid nitrogen storage means and an introduction path for introducing liquid nitrogen in the liquid nitrogen storage means into the rectification column as a cold source for liquefying compressed air are provided from outside the apparatus. By storing the liquid nitrogen to be stored in the liquid nitrogen storage means, liquid nitrogen supplied from outside the apparatus can be used.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing one embodiment of a high-purity nitrogen gas producing apparatus of the present invention.
FIG. 2 is a configuration diagram of a main part of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air compressor 5 Main heat exchanger 7 Rectification tower 8, 9 Liquid air 17 Liquid air reservoir 18 Condenser 20 Pipe 30 Guide pipe

Claims (2)

外部より取り入れた空気を圧縮する空気圧縮手段と、この空気圧縮手段により圧縮された圧縮空気を冷却する熱交換器と、この熱交換器を経由し超低温に冷却された圧縮空気の一部を液化して内部に溜め窒素を気体として保持する精留塔と、この精留塔の上部に設けられた凝縮器と、上記凝縮器で還流液を製造するための液体空気溜めと、上記精留塔の底部の貯溜液体空気を上記液体空気溜めに送給する供給路とを備え、上記液体空気溜めに送給した液体空気の一部を上記熱交換器の中間部に導入して熱交換させ気化させたのち外部へ放出する放出路を設けたことを特徴とする高純度窒素ガス製造装置。Air compression means for compressing the air taken in from outside, a heat exchanger for cooling the compressed air compressed by this air compression means, and a part of the compressed air cooled to ultra-low temperature via this heat exchanger A rectification column that holds nitrogen therein as a gas, a condenser provided at an upper part of the rectification column, a liquid air reservoir for producing a reflux liquid in the condenser, and a rectification column. A supply passage for supplying the stored liquid air at the bottom of the liquid air reservoir to the liquid air reservoir, and introducing a part of the liquid air supplied to the liquid air reservoir to an intermediate portion of the heat exchanger to exchange heat and vaporize. An apparatus for producing high-purity nitrogen gas, characterized in that a discharge path for discharging the gas to the outside is provided after the discharge. 液体窒素貯蔵手段と、この液体窒素貯蔵手段内の液体窒素を圧縮空気液化用の寒冷源として上記精留塔内に導く導入路とを備えている請求項１記載の高純度窒素ガス製造装置。2. The high-purity nitrogen gas producing apparatus according to claim 1, further comprising: a liquid nitrogen storage means; and an introduction path for guiding liquid nitrogen in the liquid nitrogen storage means into the rectification column as a cold source for liquefying compressed air.
JP2002180225A 2002-06-20 2002-06-20 High-purity nitrogen gas manufacturing device Pending JP2004020161A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002180225A JP2004020161A (en) 2002-06-20 2002-06-20 High-purity nitrogen gas manufacturing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002180225A JP2004020161A (en) 2002-06-20 2002-06-20 High-purity nitrogen gas manufacturing device

Publications (1)

Publication Number Publication Date
JP2004020161A true JP2004020161A (en) 2004-01-22

Family

ID=31177415

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002180225A Pending JP2004020161A (en) 2002-06-20 2002-06-20 High-purity nitrogen gas manufacturing device

Country Status (1)

Country Link
JP (1) JP2004020161A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007003097A (en) * 2005-06-23 2007-01-11 Air Water Inc Nitrogen generating method and device using the same
JP2019178816A (en) * 2018-03-30 2019-10-17 大陽日酸株式会社 Air liquefaction separation device and shutdown method for air liquefaction separation device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007003097A (en) * 2005-06-23 2007-01-11 Air Water Inc Nitrogen generating method and device using the same
JP2019178816A (en) * 2018-03-30 2019-10-17 大陽日酸株式会社 Air liquefaction separation device and shutdown method for air liquefaction separation device

Similar Documents

Publication Publication Date Title
CA2893197C (en) Argon production method and apparatus
US20060272352A1 (en) Air separator
JP2585955B2 (en) Air separation equipment
JP2005134036A (en) Air separator, and its operating method
JPS63163771A (en) Carbon monoxide separating purifier
JP5005894B2 (en) Nitrogen generation method and apparatus used therefor
JP3719832B2 (en) Ultra high purity nitrogen and oxygen production equipment
JPH02293575A (en) Air separation device
JP2004020161A (en) High-purity nitrogen gas manufacturing device
JP3447437B2 (en) High-purity nitrogen gas production equipment
JPS59164874A (en) Device for manufacturing nitrogen gas
JP3181546B2 (en) Method and apparatus for producing nitrogen and argon from air
JP2001033155A (en) Air separator
JP2997939B2 (en) Recovery and utilization of evaporative gas in low-temperature storage tank
JP3539709B2 (en) Air separation equipment
JPH11325720A (en) Manufacture of ultra-high-purity nitrogen gas and device therefor
JPH0816583B2 (en) Carbon monoxide separation and purification equipment
JPH0882476A (en) Apparatus for producing high-purity nitrogen gas
JP3969874B2 (en) Air liquefaction separator
JP3021389B2 (en) High-purity nitrogen gas production equipment
JPH02140586A (en) Air separating device
JP3532466B2 (en) Air separation device
JPH0789011B2 (en) Carbon monoxide separation and purification equipment
JPH0712455A (en) Nitrogen gas manufacturing device
JPH0587447A (en) Producing apparatus for nitrogen gas

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20041122

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20041130

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20050329