JP2672251B2 - Nitrogen gas production equipment - Google Patents

Nitrogen gas production equipment

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Publication number
JP2672251B2
JP2672251B2 JP5198415A JP19841593A JP2672251B2 JP 2672251 B2 JP2672251 B2 JP 2672251B2 JP 5198415 A JP5198415 A JP 5198415A JP 19841593 A JP19841593 A JP 19841593A JP 2672251 B2 JP2672251 B2 JP 2672251B2
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JP
Japan
Prior art keywords
liquid nitrogen
nitrogen
nitrogen gas
gas
liquid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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JP5198415A
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Japanese (ja)
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JPH06341760A (en
Inventor
明 吉野
Original Assignee
大同ほくさん 株式会社
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Priority to JP5198415A priority Critical patent/JP2672251B2/en
Publication of JPH06341760A publication Critical patent/JPH06341760A/en
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Publication of JP2672251B2 publication Critical patent/JP2672251B2/en
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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
    • F25J3/04624—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
    • 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
    • F25J3/04248—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
    • F25J3/04763—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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/42—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
    • F25J2280/00—Control of the process or apparatus
    • F25J2280/02—Control in general, load changes, different modes ("runs"), measurements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/62—Details of storing a fluid in a tank

Description

【発明の詳細な説明】 【０００１】 【産業上の利用分野】この発明は、窒素ガス製造装置に
関するものである。 【０００２】 【従来の技術】電子工業では極めて多量の窒素ガスが使
用されている。このため、安価な窒素ガスの供給が望ま
れ、その要望に応えるためにＰＳＡ方式が導入され、そ
れによつて窒素ガスが製造され供給されるようになつて
いる。このＰＳＡ方式による窒素ガス製造装置を図１に
示す。図において、１は空気取入口、２は空気圧縮機、
３はアフタークーラー、３ａは冷却水供給路、４は油水
セパレーターである。５は第１の吸着槽、６は第２の吸
着槽であり、Ｖ1 およびＶ2 は空気作動弁で、空気圧縮
機２によつて圧縮された空気を弁作用により吸着槽６に
送り込む。Ｖ3 およびＶ4 は真空弁であり、吸着槽５，
６内を真空ポンプ６ａの作用により真空状態にする。６
ｂは真空ポンプ６ａに冷却水を供給する冷却パイプ、６
ｃはサイレンサー、６ｄはその排気パイプである。
Ｖ5 ，Ｖ6 ，Ｖ7 およびＶ9 は空気作動弁である。７は
製品槽であり、パイプ８により吸着槽５，６に接続され
ている。７ａは製品窒素ガス取出パイプ、７ｂは不純物
分析計、７ｃは流量計である。この窒素ガス製造装置
は、空気圧縮機２により空気を圧縮し、この空気圧縮機
２に付随するアフタークーラー３によつて圧縮された空
気を冷却してセパレーター４で凝縮水を除去し、空気作
動弁Ｖ1 またはＶ2 を経由させて吸着槽５，６に送入す
る。２基の吸着槽５，６はそれぞれ酸素吸着用のカーボ
ンモレキユラシーブを内蔵しており、これらの吸着槽
５，６にはプレツシヤースイング方式により１分間毎に
交互に圧縮空気が送り込まれる。この場合、圧縮空気の
送り込まれていない吸着槽５，６は真空ポンプ６ａの作
用により内部が真空状態にされる。すなわち、空気圧縮
機２により圧縮された空気は、一方の吸着槽５内に入り
カーボンモレキユラシーブによつてそのなかの酸素分を
吸着除去され、窒素ガスとなつて弁Ｖ5 ，Ｖ6 ，Ｖ9 を
経て製品槽７に送られパイプ７ａから取り出される。こ
の時、他方の吸着槽６は、空気圧縮機２からの空気が弁
Ｖ2 の閉成によつて遮断され、かつ弁Ｖ4 の開成によつ
て内部が真空ポンプ６ａにより真空吸引される。その結
果、カーボンモレキユラシーブに吸着された酸素が吸引
除去されカーボンモレキユラシーブが再生される。この
ようにして、吸着槽５，６から交互に窒素ガスが製品槽
７に送られ製品窒素ガスが連続的に得られる。 【０００３】 【発明が解決しようとする課題】上記の窒素ガス製造装
置は、カーボンモレキユラシーブが酸素を選択的に吸着
するという特性を利用して窒素ガスを製造するため、安
価に窒素ガスを得ることができる。しかしながら、前記
のように、２基の吸着槽５，６に１分間毎に交互に圧縮
空気を送り、それと同時に、他方の吸着槽内を真空吸引
するため、弁が多数必要になるとともに、弁操作も煩雑
になり故障が多発しやすいという欠点を有している。そ
のため、２個１組の吸着槽５，６を２組設け、１組を予
備としなければならないのが実情である。したがつて、
設備費がかさむという欠点も有している。 【０００４】他方、従来の深冷液化方式の窒素ガス製造
装置は、圧縮機で圧縮された圧縮原料空気の冷却用熱交
換器の冷却のために、膨脹タービンを用い、これを精留
塔内に溜る液体空気（深冷液化分離により低沸点の窒素
はガスとして取り出され、残部が酸素リツチな液体空気
となつて溜る）から蒸発したガスの圧力で駆動するよう
になつている。ところが、膨脹タービンは回転速度が極
めて大（数万回／分）であつて負荷変動（製品窒素の取
出量《需要量》の変動）に対する追従運転が困難である
ため、負荷変動時に製品の純度がばらつくという難点を
有している。また、このものは高速回転するため機械構
造上高精度が要求され、かつ高価であり、機構が複雑な
ため特別に養成した要員が必要という難点も有してい
る。すなわち、膨脹タービンは高速回転部を有するた
め、上記のような諸問題を生じるのであり、このような
高速回転部を有する膨脹タービンの除去に対して強い要
望があつた。 【０００５】 【課題を解決するための手段】この発明は、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
手段によつて圧縮された圧縮空気中の炭酸ガスと水分と
を除去する除去手段と、この除去手段を経た圧縮空気を
超低温に冷却する熱交換手段と、この熱交換手段により
超低温に冷却された圧縮空気の一部を液化して底部に溜
め窒素のみを上部側から気体として取り出す精留塔を備
えた窒素ガス製造装置において、精留塔の上部に設けら
れ液体窒素の冷熱により還流液をつくりこれを連続的に
精留塔内へ流下させる分縮器と、装置外から液体窒素の
供給を受けこれを貯蔵する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寒冷源として上記精留塔
内に導く導入路と、上記分縮器に対する上記液体窒素貯
蔵手段からの液体窒素の供給量を制御することにより上
記分縮器内の液体窒素の液面を一定に制御する制御手段
と、上記精留塔から気体として取り出される窒素ガスお
よび上記精留塔内において寒冷源としての作用を終え気
化した上記液体窒素を上記熱交換手段を経由させ上記圧
縮空気と熱交換させることにより温度上昇させ製品窒素
ガスとする窒素ガス取出路を備えたことを特徴とする窒
素ガス製造装置をその要旨とするものである。 【０００６】すなわち、この発明の窒素ガス製造装置
は、液体窒素の蒸発熱を利用して、精留塔に送り込まれ
る圧縮空気を冷却し、圧縮空気の一部を液化分離して窒
素を気体のままで保持し、これを、精留塔における寒冷
源としての作用を終えて気化した液体窒素と合わせて製
品窒素ガスとして取り出すため、膨脹タービンが不要に
なり、膨脹タービンに起因する上記負荷変動時における
純度ばらつき等の弊害を回避でき、かつ窒素ガスを安価
に得ることができるようになる。 【０００７】つぎに、この発明を実施例にもとづいて詳
しく説明する。 【０００８】 【実施例】図２はこの発明の一実施例の構成図である。
図において、９は空気圧縮機、１０はドレン分離器、１
１はフロン冷却器、１２は２個１組の吸着筒である。吸
着筒１２は内部にモレキユラシーブが充填されていて空
気圧縮機９により圧縮された空気中のＨ2 ＯおよびＣＯ
2 を吸着除去する作用をする。１３は第１の熱交換器で
あり、吸着筒１２によりＨ2 ＯおよびＣＯ2 を吸着除去
された圧縮空気が送り込まれる。１４は第２の熱交換器
であり、第１の熱交換器１３を経た圧縮空気が送り込ま
れる。１５は液体窒素を溜めるための分縮器１６を塔頂
に備えた精留塔であり、第１および第２の熱交換器１
３，１４により超低温に冷却された圧縮空気をさらに冷
却し、その一部を液化して底部に溜め、窒素のみを気体
状態で上部から取り出すようになつている。すなわち、
この精留塔１５は、第１および第２の熱交換器１３，１
４を経て超低温（約−１７０℃）に冷却された圧縮空気
を、パイプ１７により精留塔１５の底部の貯溜液体空気
（Ｎ2 ５０〜７０％，Ｏ2３０〜５０％）１８中を通し
てさらに冷却し、ついで膨脹弁１９を経て内部に噴射さ
せ、精留棚および分縮器１６で酸素等を液化し、窒素を
気体のまま残すようになつている。この分縮器１６は、
多数のチユーブ２０が植設されている仕切板２１によつ
て塔部２２と区切られていて、仕切板２１上には圧縮空
気の液化分離の際に生じた液体窒素および液体窒素貯槽
２３から第１の導入路パイプ２４を経て供給された液体
窒素が貯溜される。そして、上記分縮器１６は、精留棚
を経て精留塔１５内を上昇する圧縮空気由来のガスをチ
ユーブ２０内に案内して貯溜液体窒素の冷熱で冷却し、
そのガスを分縮すると同時にそのガス中の微量酸素（沸
点−１８３℃）等を液化して流下させ窒素（沸点−１９
６℃）を気体のまま上方に移行させるようになつてい
る。上方に移行した気体窒素の一部は先に述べたように
液化して仕切板２１上の貯溜液体窒素となる。 【０００９】この場合、精留塔１５の塔部２２内に噴射
された圧縮空気は、チユーブ２０から流下する液体酸素
と向流的に接触するため、酸素の液化分離が一層促進さ
れる。２５は上記分縮器１６内の貯溜液体窒素の液面を
一定に保つ液面計であり、分縮器１６内の液体窒素の液
面の変動に応じてバルブ２６を制御し液体窒素貯槽２３
からの液体窒素の供給量を制御する。２７は分縮器１６
の上部に溜まつた窒素ガスを取り出す取り出しパイプ
で、超低温の窒素ガスを第２，第１の熱交換器１４，１
３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２８に送り込む作用をする。
２９は精留塔１５の底部の貯溜液体空気１８を第２およ
び第１の熱交換器１４，１３に送り込む送り込みパイプ
で、２９ａは保圧弁である。上記第２および第１の熱交
換器１４，１３で熱交換（熱交換器１４，１３内の圧縮
空気の冷却）を終えた上記貯溜液体空気は気化して第１
の熱交換器１３から矢印Ａのように放出されるようにな
つている。３０はバツクアツプ系ラインであり、液体窒
素蒸発器３１，これに上記液体窒素貯槽２３から液体窒
素を供給する第２の導入路パイプ３０ａ，上記液体窒素
蒸発器３１で気化生成した窒素ガスをメインパイプ２８
に送入する案内パイプ３０ｂ，この案内パイプ３０ｂに
設けられた圧力調節弁３３ａから構成されている。上記
圧力調節弁３３ａは、２次側（使用側）の圧力が設定圧
力より下がると、弁を開き、または弁の開度を調節し、
２次側の圧力が設定圧力を保つよう作用する。このバツ
クアツプ系ライン３０では、精留塔ラインが故障した
り、または製品窒素ガスの需要量が大幅に増加したりし
てメインパイプ２８内の圧力が下がると、上記圧力調節
弁３３ａが開成作動するため、上記液体窒素貯槽２３か
ら液体窒素が液体窒素蒸発器３１に流れて気化し、その
生成気化窒素ガスが製品窒素ガスとして上記メインパイ
プ２８内に流入するようになつている。３２は不純物分
析計であり、メインパイプ２８から送り出される製品窒
素ガスの純度を分析し、純度の低いときは、弁３４，３
４ａを作動させて製品窒素ガスを矢印Ｂのように外部に
逃気する作用をする。３３はメインパイプ２８に設けら
れた圧力調節弁である。 【００１０】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９により空気を圧
縮し、ドレン分離器１０により圧縮された空気中の水分
を除去してフロン冷却器１１により冷却し、その状態で
モレキユラシーブが充填されている吸着筒１２に送り込
み、空気中のＨ2 ＯおよびＣＯ2 を吸着除去する。つい
で、Ｈ2 Ｏ，ＣＯ2 が吸着除去された圧縮空気を第１の
熱交換器１３および第２の熱交換器１４に送り込んで超
低温に冷却し、さらに精留塔１５の下部の貯溜液体空気
１８で冷却したのち、精留塔１５内に噴射させる。そし
て、窒素と酸素の沸点の差（酸素の沸点−１８３℃，窒
素の沸点−１９６℃）を利用して空気中の酸素を液化
し、窒素を気体のまま取り出して第１または第２の熱交
換器１３，１４に送り込み常温近くまで昇温させメイン
パイプ２８から窒素ガスとして取り出す。この場合、液
体窒素貯槽２３内の液体窒素は、精留塔１５の分縮器１
６の寒冷源として作用し、それ自身は気化してメインパ
イプ２８内に送り込まれ、上記精留塔１５から得られる
空気中の窒素ガスと合わされ製品窒素ガスとして取り出
される。 【００１１】このように、この窒素ガス製造装置によれ
ば、液体窒素の蒸発熱を利用して圧縮空気を冷却し、そ
れを精留塔１５に送り込んで酸素等を分離し窒素のみを
取り出し、これを寒冷源となつた液体窒素（気体状にな
つている）と合わせて製品窒素ガスとするため、膨脹タ
ービンに起因する前記弊害を全く生じず、極めて安価
に、かつ高純度の窒素ガスを得ることができる。 【００１２】すなわち、精留塔１５を高精度に設定する
ことにより、純度９９．９９９％の窒素ガスを純度ばら
つきなく得ることができるようになる。これに対して、
ＰＳＡ方式の窒素ガス製造装置では、たかだか９９．３
％の純度のものしか得られないのであり、膨脹タービン
を用いる深冷液化分離装置では負荷変動時に純度がばら
つくのである。そのうえ、この窒素ガス製造装置は、製
品窒素ガスの需要量に変動が生じても、その変動に応じ
て液面計２５がバルブ２６の開度や開閉を制御するた
め、迅速に対応できる。そして、液面計２５によるバル
ブ制御では対応できないような需要量の大幅な増加時、
もしくは精留塔ラインの故障によつて精留塔１５から製
品窒素ガスが得られなくなつたりした時等に、バツクア
ツプ系ライン３０が作動して液体窒素貯槽２３内の液体
窒素を直接蒸発器３１で気化し、これを製品窒素ガスと
してメインパイプ２８に流すため、需要量の大幅増加時
における製品窒素ガスの純度低下現象の発生や、製品窒
素ガス供給のとだえが回避され、常時安定に製品窒素ガ
スを供給しうるのであり、これが大きな特徴である。し
かも、この装置は、１基の液体窒素貯槽２３を、精留塔
ラインとバツクアツプラインの双方の貯槽として共用す
るため、設備費を大幅に節約できると同時に、液体窒素
貯槽の設置スペースを小さくでき、装置全体のコンパク
ト化を実現できるのであり、これも大きな特徴である。 【００１３】上記のように、この発明の窒素ガス製造装
置によれば高純度の窒素ガスが安定な状態で得られるた
め、それをそのまま電子工業向けにすることができる。
そして、このガスには炭酸ガスが含まれていない（製造
装置内で除去されている）ため、炭酸ガス用の吸着槽を
別個に装備する必要がない。さらに、少量の液体窒素を
供給するだけで大量の窒素ガスが得られるようになる。
すなわち、この発明の窒素ガス製造装置によれば、液体
窒素貯槽２３から１００Ｎｍ3 （ガス換算）の液体窒素
を分縮器１６に送り込むことにより、１０００Ｎｍ3 の
製品窒素ガスを得ることができる。このように、この製
造装置によれば少量の液体窒素を供給するだけで、その
１０倍の製品窒素ガスが得られるようになるのである。
したがつて、極めて安価な窒素ガスが得られるようにな
る。また、ＰＳＡ方式や膨脹タービン使用の従来の深冷
液化分離方式による窒素ガス製造装置に比べて、装置が
簡単であるため装置全体が安価であり、かつ多数の弁等
も不要なため、装置の信頼度が大である。また、膨脹タ
ービンに起因する特別な要員も不要になる。 【００１４】図３は他の実施例の構成図である。この窒
素ガス製造装置は、精留塔１５の上方に凝縮器３５を付
帯させて連通パイプ３６により分縮器１６の上部と連通
させ、分縮器１６の上部に溜められた窒素ガス（分縮器
１６によつて酸素が液化分離され得られた窒素ガス＋液
体窒素貯槽２３から供給された液体窒素の気化窒素ガ
ス）を凝縮器３５内に入れるように構成している。そし
て、この窒素ガスを、一端３５ｂが精留塔１５の底部と
連通し他端３５ｃが第２および第１の熱交換器１４，１
３を通つて空気中に開放されている冷却パイプ３５ａで
冷却して（冷媒は精留塔１５底部の貯溜液体空気）その
一部を凝縮させ、生成した液体窒素３７を、ヘツド差を
利用して戻しパイプ３８から分縮器１６内へ戻し、未凝
縮の窒素ガスを第２および第１の熱交換器１４，１３を
通してメインパイプ２８に送り込むようにしている。そ
れ以外の部分は前記の実施例と同じであり、同一部分に
同一符号を付している。 【００１５】すなわち、この窒素ガス製造装置は、分縮
器１６の上部から得られる製品窒素ガスを凝縮器３５に
導き、その一部を凝縮させて分縮器１６内に戻し、液体
窒素貯槽２３から供給される液体窒素に合わせるように
するため、上記凝縮器３５が精留作用を発揮するように
なる。したがつて、前記の実施例の装置に比べて、液体
窒素貯槽２３に供給する液体窒素として純度の低いもの
を用いうるという優れた効果を得ることができるように
なる。 【００１６】図４はさらに他の実施例の構成図である。
この窒素ガス製造装置は、戻しパイプ３８を分縮器１６
ではなく、精留塔１５の上部に接続して凝縮液体窒素を
精留塔１５の上部へ戻すようにしている。それ以外の部
分は図３の実施例と同じであり同一部分に同一符号を付
している。 【００１７】この実施例によれば、上記と同様の効果が
得られるほか、還流液量が増加するため精留効果の向上
も実現しうるようになる。 【００１８】 【発明の効果】以上のように、この発明の窒素ガス製造
装置は、膨脹タービンを用いず、それに代えて何ら回転
部を持たない液体窒素貯槽のような液体窒素貯蔵手段を
用いるため、装置全体として回転部がなくなり故障が全
く生じない。しかも膨脹タービンは高価であるのに対し
て液体窒素貯槽は安価であり、また特別な要員も不要に
なる。そのうえ、膨脹タービン（窒素精留塔体に溜まる
液体空気から蒸発したガスの圧力で駆動する）は高速回
転機器であるため、負荷変動（製品窒素ガスの取出量の
変化）に対するきめ細かな追従運転が困難であり、した
がつて、製品窒素ガスの取出量の変化に応じて発生寒冷
量を変化させ窒素ガス製造原料である圧縮空気を常時一
定温度に冷却することが困難であり、その結果、これを
用いた装置では、頻繁に低純度のものがつくりだされ全
体的に製品窒素ガスの純度が低くなる。この発明の装置
は、膨脹タービンに代えて液体窒素貯槽を用い、供給量
のきめ細かい調節が可能な液体窒素を寒冷源として用い
るため、負荷変動に対するきめ細かな追従が可能とな
り、純度が安定していて極めて高い窒素ガスを製造しう
るようになる。特に、この発明の装置は、液体窒素貯蔵
手段からの液体窒素を精留塔の内部空間へ直接供給する
のではなく、特殊構造の分縮器の貯溜液体窒素中に供給
して精留塔内で液体窒素のフラツシング（高圧霧状化）
が生じないようにする（精留塔の内部空間へ直接供給す
る場合には、フラツシング時に液体から気体への体積膨
張により内部空間の圧力が高くなり精留効果が悪くなつ
て純度が下がり、それ以外の時には一定純度が得られ
る。このようにフラツシングにもとづき製品窒素の純度
ばらつきが生じるため、フラツシングが生じないように
する）と同時に、制御手段によつて上記分縮器に対する
液体窒素貯蔵手段からの液体窒素の供給量を制御して分
縮器の液面を一定に制御するため、負荷変動に対して極
めて迅速に対応でき、その際全く製品窒素ガスの純度ば
らつきを生じない。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrogen gas production apparatus. 2. Description of the Related Art An extremely large amount of nitrogen gas is used in the electronic industry. Therefore, inexpensive nitrogen gas is desired to be supplied, and the PSA method has been introduced to meet the request, whereby nitrogen gas is manufactured and supplied. FIG. 1 shows a nitrogen gas production apparatus using this PSA method. In the figure, 1 is an air intake, 2 is an air compressor,
3 is an aftercooler, 3a is a cooling water supply passage, and 4 is an oil / water separator. Reference numeral 5 is a first adsorption tank, 6 is a second adsorption tank, V 1 and V 2 are air operated valves, and the air compressed by the air compressor 2 is sent to the adsorption tank 6 by a valve action. V 3 and V 4 are vacuum valves, and the adsorption tank 5,
The inside of 6 is evacuated by the action of the vacuum pump 6a. 6
b is a cooling pipe for supplying cooling water to the vacuum pump 6a, 6
c is a silencer, and 6d is its exhaust pipe.
V 5 , V 6 , V 7 and V 9 are air operated valves. 7 is a product tank, which is connected to the adsorption tanks 5 and 6 by a pipe 8. Reference numeral 7a is a product nitrogen gas extraction pipe, 7b is an impurity analyzer, and 7c is a flow meter. This nitrogen gas production apparatus compresses air by an air compressor 2, cools the air compressed by an aftercooler 3 attached to the air compressor 2, removes condensed water by a separator 4, and operates the air. It is fed into the adsorption tanks 5 and 6 via the valve V 1 or V 2 . Each of the two adsorption tanks 5 and 6 contains a carbon molecular sieve for adsorbing oxygen, and compressed air is alternately sent to the adsorption tanks 5 and 6 by the precession swing method every one minute. . In this case, the suction tanks 5 and 6 to which the compressed air is not fed are brought into a vacuum state by the action of the vacuum pump 6a. That is, the air compressed by the air compressor 2 enters into one of the adsorption tanks 5, the oxygen content therein is adsorbed and removed by the carbon molecular sieve, and the air is converted into nitrogen gas and the valves V 5 , V 6 , It is sent to the product tank 7 via V 9 and taken out from the pipe 7a. At this time, in the other adsorption tank 6, the air from the air compressor 2 is shut off by closing the valve V 2 , and the inside is vacuumed by the vacuum pump 6a by opening the valve V 4 . As a result, oxygen adsorbed on the carbon molecular sieve is removed by suction, and the carbon molecular sieve is regenerated. In this way, nitrogen gas is alternately sent from the adsorption tanks 5 and 6 to the product tank 7, and product nitrogen gas is continuously obtained. The above-mentioned nitrogen gas producing apparatus produces nitrogen gas by utilizing the characteristic that carbon molecular sieve selectively adsorbs oxygen, so that nitrogen gas can be produced inexpensively. Obtainable. However, as described above, compressed air is alternately sent to the two adsorption tanks 5 and 6 every minute, and at the same time, the other adsorption tank is vacuum-sucked, so that a large number of valves are required and It has a drawback that the operation is complicated and failures are likely to occur frequently. Therefore, in reality, it is necessary to provide two sets of two adsorption tanks 5 and 6 and one set as a spare. Therefore,
It also has the drawback of high equipment costs. On the other hand, a conventional cryogenic liquefaction type nitrogen gas producing apparatus uses an expansion turbine for cooling a heat exchanger for cooling compressed raw material air compressed by a compressor, which is used in a rectification column. It is driven by the pressure of the gas evaporated from the liquid air that accumulates (low-boiling-point nitrogen is taken out as a gas by cryogenic liquefaction separation, and the rest is stored as oxygen-rich liquid air). However, the expansion turbine has a very high rotational speed (tens of thousands of times / minute) and it is difficult to follow the load fluctuation (fluctuation of product nitrogen extraction amount <demand amount>). It has a drawback that it varies. Further, since this machine rotates at high speed, it requires high precision in terms of mechanical structure, is expensive, and has a complicated mechanism, which requires specially trained personnel. That is, since the expansion turbine has the high-speed rotating part, the above-mentioned problems occur. Therefore, there is a strong demand for removing the expansion turbine having the high-speed rotating part. According to the present invention, an air compression means for compressing air taken in from the outside, and carbon dioxide gas and moisture in compressed air compressed by the air compression means are removed. Removing means, a heat exchange means for cooling the compressed air passing through this removing means to an ultra low temperature, and a part of the compressed air cooled to an ultra low temperature by this heat exchanging means for liquefying and storing only nitrogen in the bottom from the upper side. In a nitrogen gas production apparatus equipped with a rectification tower that takes out as a gas, a dephlegmator installed at the upper part of the rectification tower to make a reflux liquid by the cold heat of liquid nitrogen and continuously flow it down into the rectification tower, and the device. Liquid nitrogen storage means for receiving and supplying liquid nitrogen from the outside, an introduction path for guiding the liquid nitrogen in the liquid nitrogen storage means into the rectification column as a cold source, and the liquid nitrogen for the partial condenser. Storage Control means for controlling the liquid level of the liquid nitrogen in the partial condenser to a constant level by controlling the supply amount of the liquid nitrogen from the stage, the nitrogen gas taken out as a gas from the rectification column and the rectification column In the above, the liquid nitrogen that has finished the action as a cold source is vaporized and the temperature of the liquid nitrogen is increased by exchanging heat with the compressed air through the heat exchanging means to obtain a product nitrogen gas. The main point is a nitrogen gas production device. That is, the nitrogen gas producing apparatus of the present invention utilizes the heat of vaporization of liquid nitrogen to cool the compressed air sent to the rectification column and liquefy and separate a part of the compressed air to convert nitrogen into a gas. The expansion turbine is no longer necessary because it is retained as it is and taken out as product nitrogen gas together with liquid nitrogen that has vaporized after completing the action as a cold source in the rectification tower, and when the load changes due to the expansion turbine. It is possible to avoid adverse effects such as variations in purity, and to obtain nitrogen gas at low cost. Next, the present invention will be described in detail based on embodiments. FIG. 2 is a block diagram of an embodiment of the present invention.
In the figure, 9 is an air compressor, 10 is a drain separator, and 1
Reference numeral 1 is a CFC cooler, and 12 is a set of two adsorption tubes. The adsorption cylinder 12 is filled with molecular sieve and has H 2 O and CO in the air compressed by the air compressor 9.
It acts to adsorb and remove 2 . Reference numeral 13 denotes a first heat exchanger, into which compressed air from which H 2 O and CO 2 have been adsorbed and removed by the adsorption column 12 is fed. Reference numeral 14 is a second heat exchanger, into which the compressed air that has passed through the first heat exchanger 13 is fed. Reference numeral 15 is a rectification column equipped with a partial condenser 16 for accumulating liquid nitrogen at the top of the column, and the first and second heat exchangers 1
The compressed air cooled to an ultra-low temperature by 3, 14 is further cooled, a part of it is liquefied and stored in the bottom part, and only nitrogen is taken out from the upper part in a gas state. That is,
The rectification tower 15 includes the first and second heat exchangers 13, 1
The compressed air cooled to ultra-low temperature (about -170 ° C.) via 4 is passed through the pipe 17 into the stored liquid air (N 2 50 to 70%, O 2 30 to 50%) 18 at the bottom of the rectification column 15. It is cooled and then injected through the expansion valve 19 to liquefy oxygen and the like in the rectification shelf and the partial condenser 16, and leave nitrogen as a gas. This demultiplexer 16 is
It is separated from the tower portion 22 by a partition plate 21 in which a large number of tubes 20 are planted, and the partition plate 21 is separated from the liquid nitrogen and liquid nitrogen storage tanks 23 generated during the liquefaction separation of compressed air. The liquid nitrogen supplied via the first introduction pipe 24 is stored. Then, the partial condenser 16 guides the gas derived from the compressed air rising in the rectification tower 15 through the rectification shelf into the tube 20 and cools it with the cold heat of the stored liquid nitrogen,
At the same time that the gas is partially condensed, a trace amount of oxygen (boiling point −183 ° C.) and the like in the gas is liquefied and allowed to flow down, and nitrogen (boiling point −19 ° C.)
6 ° C.) is allowed to move upward as a gas. Part of the gaseous nitrogen that has moved upward is liquefied as described above to become the stored liquid nitrogen on the partition plate 21. In this case, the compressed air injected into the column portion 22 of the rectification column 15 comes into countercurrent contact with the liquid oxygen flowing down from the tube 20, so that the liquefaction separation of oxygen is further promoted. A liquid level gauge 25 keeps the liquid level of the stored liquid nitrogen in the decompressor 16 constant, and controls the valve 26 according to the fluctuation of the liquid level of the liquid nitrogen in the decompressor 16 to control the liquid nitrogen storage tank 23.
Controls the supply of liquid nitrogen from. 27 is a demultiplexer 16
With the take-out pipe for taking out the nitrogen gas accumulated in the upper part of the reactor, the ultra-low temperature nitrogen gas is fed to the second and first heat exchangers 14, 1.
It guides the inside of the pipe 3 and exchanges heat with the compressed air fed therein to bring it to room temperature and feeds it into the main pipe 28.
29 is a feed pipe for feeding the stored liquid air 18 at the bottom of the rectification column 15 to the second and first heat exchangers 14 and 13, and 29a is a pressure-holding valve. The stored liquid air that has completed the heat exchange (cooling of the compressed air in the heat exchangers 14 and 13) in the second and first heat exchangers 14 and 13 is vaporized to be the first.
The heat exchanger 13 of FIG. Reference numeral 30 denotes a backup system line, which is a liquid nitrogen evaporator 31, a second introduction passage pipe 30a for supplying liquid nitrogen from the liquid nitrogen storage tank 23 to the liquid nitrogen evaporator 31, and a main pipe for the nitrogen gas vaporized and produced by the liquid nitrogen evaporator 31. 28
It is composed of a guide pipe 30b that is fed to the guide pipe 30b and a pressure control valve 33a provided on the guide pipe 30b. The pressure control valve 33a opens the valve or adjusts the opening of the valve when the pressure on the secondary side (use side) falls below a set pressure,
The pressure on the secondary side acts to maintain the set pressure. In the backup system line 30, when the pressure in the main pipe 28 is lowered due to a failure of the rectification column line or a large increase in the demand amount of product nitrogen gas, the pressure control valve 33a is opened. Therefore, the liquid nitrogen flows from the liquid nitrogen storage tank 23 to the liquid nitrogen evaporator 31 to be vaporized, and the generated vaporized nitrogen gas flows into the main pipe 28 as product nitrogen gas. An impurity analyzer 32 analyzes the purity of the product nitrogen gas sent out from the main pipe 28. When the purity is low, the valves 34 and 3 are used.
4a is operated to release the product nitrogen gas to the outside as shown by arrow B. Reference numeral 33 is a pressure control valve provided in the main pipe 28. This apparatus produces product nitrogen gas as follows. That is, the air is compressed by the air compressor 9, the water in the air compressed by the drain separator 10 is removed, and it is cooled by the freon cooler 11, and then sent to the adsorption cylinder 12 filled with the molecular sieve. , for adsorbing and removing H 2 O and CO 2 in air. Then, the compressed air from which H 2 O and CO 2 have been adsorbed and removed is sent to the first heat exchanger 13 and the second heat exchanger 14 to be cooled to an ultralow temperature, and the stored liquid air in the lower portion of the rectification column 15 is further cooled. After cooling at 18, it is injected into the rectification column 15. Then, the oxygen in the air is liquefied by utilizing the difference between the boiling points of nitrogen and oxygen (boiling point of oxygen-183 ° C., boiling point of nitrogen-196 ° C.), and the nitrogen is taken out as a gas to remove the first or second heat. It is sent to the exchangers 13 and 14 and the temperature is raised to near room temperature and taken out from the main pipe 28 as nitrogen gas. In this case, the liquid nitrogen in the liquid nitrogen storage tank 23 is the liquid nitrogen in the fractionator 1 of the rectification column 15.
6, which itself functions as a cold source, is vaporized and sent into the main pipe 28, is combined with the nitrogen gas in the air obtained from the rectification column 15, and is taken out as product nitrogen gas. As described above, according to this nitrogen gas producing apparatus, the compressed air is cooled by utilizing the heat of vaporization of liquid nitrogen, and it is sent to the rectification column 15 to separate oxygen and the like and take out only nitrogen, Since this is combined with liquid nitrogen (which is in a gaseous state) that is used as a cold source to produce product nitrogen gas, the above-mentioned harmful effects caused by the expansion turbine are not caused at all, and extremely high-purity nitrogen gas can be produced at extremely low cost. Obtainable. That is, by setting the rectification column 15 with high accuracy, it is possible to obtain nitrogen gas having a purity of 99.999% without variations in purity. On the contrary,
At most 99.3 in the PSA type nitrogen gas production equipment
Since only the one with a purity of 10% can be obtained, the refrigerating liquefaction separation apparatus using the expansion turbine has a variation in the purity when the load changes. In addition, this nitrogen gas manufacturing apparatus can respond promptly even if the demand amount of the product nitrogen gas fluctuates, because the liquid level gauge 25 controls the opening degree and opening / closing of the valve 26 according to the fluctuation. Then, when the demand volume increases significantly that cannot be handled by the valve control by the liquid level gauge 25,
Alternatively, when product nitrogen gas cannot be obtained from the rectification tower 15 due to a failure of the rectification tower line, the backup system line 30 is activated to directly remove the liquid nitrogen in the liquid nitrogen storage tank 23 from the evaporator 31. Since it is vaporized by the above, and this is supplied to the main pipe 28 as product nitrogen gas, the phenomenon of the purity decrease of the product nitrogen gas at the time of a large increase in the demand amount and the pouring of the product nitrogen gas supply are avoided, and the product nitrogen is always stable. It can supply gas, which is a major feature. Moreover, since this device shares one liquid nitrogen storage tank 23 as both the storage tank for the rectification tower line and the storage tank for the back up line, the equipment cost can be greatly saved and the installation space for the liquid nitrogen storage tank can be reduced. It is possible to realize a compact device as a whole, which is also a major feature. As described above, according to the nitrogen gas production apparatus of the present invention, high-purity nitrogen gas can be obtained in a stable state, so that it can be directly applied to the electronic industry.
Since this gas does not contain carbon dioxide gas (which has been removed in the manufacturing apparatus), it is not necessary to separately install an adsorption tank for carbon dioxide gas. Furthermore, a large amount of nitrogen gas can be obtained by supplying a small amount of liquid nitrogen.
That is, according to the nitrogen gas production apparatus of the present invention, 1000 Nm 3 of product nitrogen gas can be obtained by sending 100 Nm 3 (gas equivalent) of liquid nitrogen from the liquid nitrogen storage tank 23 to the partial condenser 16. As described above, according to this manufacturing apparatus, by supplying a small amount of liquid nitrogen, product nitrogen gas which is 10 times as much as the product nitrogen gas can be obtained.
Therefore, extremely inexpensive nitrogen gas can be obtained. Further, as compared with the conventional cryogenic liquefaction separation method nitrogen gas production apparatus using the PSA method or expansion turbine, the apparatus is simple and the entire apparatus is inexpensive, and a large number of valves and the like are not required. The reliability is high. Also, no special personnel are required due to the expansion turbine. FIG. 3 is a block diagram of another embodiment. In this nitrogen gas production apparatus, a condenser 35 is attached above the rectification column 15 and communicated with an upper portion of the partial condenser 16 by a communication pipe 36, and nitrogen gas accumulated in the upper portion of the partial condenser 16 (the partial condenser The nitrogen gas obtained by liquefying and separating oxygen by the vessel 16 + the vaporized nitrogen gas of liquid nitrogen supplied from the liquid nitrogen storage tank 23) is introduced into the condenser 35. One end 35b of this nitrogen gas communicates with the bottom of the rectification column 15, and the other end 35c communicates with the second and first heat exchangers 14, 1.
3 is cooled by a cooling pipe 35a that is open to the air through 3 (the refrigerant is the stored liquid air at the bottom of the rectification column 15) to partially condense it, and the generated liquid nitrogen 37 is used by utilizing the head difference. The uncondensed nitrogen gas is fed back into the main pipe 28 through the second and first heat exchangers 14 and 13 from the return pipe 38 into the partial condenser 16. The other parts are the same as those in the above-described embodiment, and the same parts are designated by the same reference numerals. That is, this nitrogen gas producing apparatus guides the product nitrogen gas obtained from the upper portion of the partial condenser 16 to the condenser 35, condenses a part thereof and returns it to the partial condenser 16, and the liquid nitrogen storage tank 23. In order to adjust to the liquid nitrogen supplied from the condenser 35, the condenser 35 comes to exert a rectification action. Therefore, it is possible to obtain an excellent effect that liquid nitrogen having a low purity can be used as the liquid nitrogen to be supplied to the liquid nitrogen storage tank 23, as compared with the apparatus of the above-described embodiment. FIG. 4 is a block diagram of still another embodiment.
In this nitrogen gas manufacturing apparatus, the return pipe 38 is connected to the dephlegmator 16
Instead, it is connected to the upper part of the rectification column 15 to return the condensed liquid nitrogen to the upper part of the rectification column 15. The other parts are the same as those in the embodiment of FIG. 3, and the same parts are designated by the same reference numerals. According to this embodiment, in addition to the same effect as described above, the rectification effect can be improved because the amount of reflux liquid is increased. As described above, the nitrogen gas production apparatus of the present invention does not use an expansion turbine, but instead uses liquid nitrogen storage means such as a liquid nitrogen storage tank having no rotating part. As a whole, there are no rotating parts and no failure occurs. Moreover, while the expansion turbine is expensive, the liquid nitrogen storage tank is inexpensive and no special personnel are required. Moreover, since the expansion turbine (driven by the pressure of the gas evaporated from the liquid air accumulated in the nitrogen rectification column) is a high-speed rotating device, it is possible to perform detailed follow-up operation for load fluctuations (changes in the amount of product nitrogen gas taken out). Therefore, it is difficult to constantly cool the compressed air, which is the raw material for producing nitrogen gas, to a constant temperature by changing the amount of generated cold according to the change in the amount of product nitrogen gas taken out. In the apparatus using, the purity of the product nitrogen gas is lowered as a whole because the product of low purity is often produced. Since the apparatus of the present invention uses a liquid nitrogen storage tank instead of the expansion turbine and liquid nitrogen whose supply amount can be finely adjusted as a cold source, it is possible to finely follow load fluctuations and the purity is stable. It becomes possible to produce extremely high nitrogen gas. In particular, in the apparatus of the present invention, the liquid nitrogen from the liquid nitrogen storage means is not directly supplied to the internal space of the rectification column, but is supplied into the stored liquid nitrogen of the dephlegmator having a special structure so that the inside of the rectification column is supplied. Liquid nitrogen flushing (high-pressure atomization)
(When directly supplying to the internal space of the rectification column, the volumetric expansion from liquid to gas at the time of flushing increases the pressure in the internal space, which deteriorates the rectification effect and reduces the purity. A certain degree of purity is obtained in all cases except for the above, because the purity of product nitrogen varies depending on the flushing so that the flushing does not occur). Since the liquid level of the liquid nitrogen is controlled to control the liquid level of the dephlegmator to be constant, it is possible to respond to a load change very quickly, and in that case, there is no variation in the purity of the product nitrogen gas.

【図面の簡単な説明】 【図１】従来例の構成図である。 【図２】この発明の一実施例の構成図である。 【図３】他の実施例の構成図である。 【図４】さらに他の実施例の構成図である。 【符号の説明】 ９ 空気圧縮機 １２ 吸着筒 １３，１４ 熱交換器 １５ 精留塔 １６ 分縮器 １８ 貯溜液体空気 ２３ 液体窒素貯槽 ２４ 第１の導入路パイプ ２５ 液面計 ２６ バルブ ２７ 取り出しパイプ ２８ メインパイプ ３０ バツクアツプライン系 ３０ａ 第２の導入路パイプ ３１ 液体窒素蒸発器 ３３，３３ａ 圧力調節弁[Brief description of the drawings] FIG. 1 is a configuration diagram of a conventional example. FIG. 2 is a configuration diagram of an embodiment of the present invention. FIG. 3 is a configuration diagram of another embodiment. FIG. 4 is a configuration diagram of still another embodiment. [Explanation of symbols] 9 Air compressor 12 adsorption cylinder 13,14 heat exchanger 15 rectification tower 16 decompressor 18 Stored liquid air 23 Liquid nitrogen storage tank 24 First Inlet Pipe 25 Level gauge 26 valves 27 Take-out pipe 28 Main pipe 30 Back-up line system 30a Second introduction path pipe 31 Liquid Nitrogen Evaporator 33, 33a Pressure control valve

Claims (1)

(57)【特許請求の範囲】 １．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つて圧縮された圧縮空気中の
炭酸ガスと水分とを除去する除去手段と、この除去手段
を経た圧縮空気を超低温に冷却する熱交換手段と、この
熱交換手段により超低温に冷却された圧縮空気の一部を
液化して底部に溜め窒素のみを上部側から気体として取
り出す精留塔を備えた窒素ガス製造装置において、精留
塔の上部に設けられ液体窒素の冷熱により還流液をつく
りこれを連続的に精留塔内へ流下させる分縮器と、装置
外から液体窒素の供給を受けこれを貯蔵する液体窒素貯
蔵手段と、この液体窒素貯蔵手段内の液体窒素を寒冷源
として上記精留塔内に導く導入路と、上記分縮器に対す
る上記液体窒素貯蔵手段からの液体窒素の供給量を制御
することにより上記分縮器内の液体窒素の液面を一定に
制御する制御手段と、上記精留塔から気体として取り出
される窒素ガスおよび上記精留塔内において寒冷源とし
ての作用を終え気化した上記液体窒素を上記熱交換手段
を経由させ上記圧縮空気と熱交換させることにより温度
上昇させ製品窒素ガスとする窒素ガス取出路を備えたこ
とを特徴とする窒素ガス製造装置。(57) [Claims] Air compression means for compressing air taken in from the outside, removal means for removing carbon dioxide gas and moisture in the compressed air compressed by this air compression means, and compressed air passed through this removal means to an ultralow temperature In a nitrogen gas production apparatus equipped with a heat exchange means for liquefying a part of the compressed air cooled to an ultra-low temperature by this heat exchange means and collecting it in the bottom part and extracting only nitrogen as gas from the upper side, A condenser provided in the upper part of the distillation tower to make a reflux liquid by the cold heat of liquid nitrogen and continuously flow it down into the rectification tower, and a liquid nitrogen storage means for receiving liquid nitrogen from outside the device and storing it. And an introduction path for introducing the liquid nitrogen in the liquid nitrogen storage means into the rectification column as a cold source and the decompressor.
Controlling the amount of liquid nitrogen supplied from the liquid nitrogen storage means
To keep the liquid surface of the liquid nitrogen in the dephlegmator constant.
Control means for controlling, nitrogen gas taken out as a gas from the rectification tower and the liquid nitrogen vaporized after finishing the action as a cold source in the rectification tower are exchanged with the compressed air through the heat exchange means. An apparatus for producing nitrogen gas, comprising a nitrogen gas take-out path for raising the temperature of the product to produce product nitrogen gas.
JP5198415A 1993-08-10 1993-08-10 Nitrogen gas production equipment Expired - Lifetime JP2672251B2 (en)

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JP5198415A JP2672251B2 (en) 1993-08-10 1993-08-10 Nitrogen gas production equipment

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Application Number Priority Date Filing Date Title
JP5198415A JP2672251B2 (en) 1993-08-10 1993-08-10 Nitrogen gas production equipment

Related Parent Applications (1)

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JP2417888A Division JP2540244B2 (en) 1990-12-28 1990-12-28 Nitrogen gas production equipment

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JPH06341760A JPH06341760A (en) 1994-12-13
JP2672251B2 true JP2672251B2 (en) 1997-11-05

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07305952A (en) * 1994-12-22 1995-11-21 Daido Hoxan Inc Preparation of nitrogen gas
CN1070385C (en) * 1997-05-14 2001-09-05 中国石油化工总公司 Improved segregation fractionating column system
JP5005894B2 (en) 2005-06-23 2012-08-22 エア・ウォーター株式会社 Nitrogen generation method and apparatus used therefor
FR2903483B1 (en) * 2006-07-04 2014-07-04 Air Liquide METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1463075A (en) * 1973-04-13 1977-02-02 Cryoplants Ltd Air separation
DE2542468A1 (en) * 1975-09-24 1977-04-07 Bayer Ag HERBICIDAL AGENT

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