JP3999865B2 - Liquid oxygen purification method and apparatus used therefor - Google Patents
Liquid oxygen purification method and apparatus used therefor Download PDFInfo
- Publication number
- JP3999865B2 JP3999865B2 JP00510598A JP510598A JP3999865B2 JP 3999865 B2 JP3999865 B2 JP 3999865B2 JP 00510598 A JP00510598 A JP 00510598A JP 510598 A JP510598 A JP 510598A JP 3999865 B2 JP3999865 B2 JP 3999865B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- oxygen
- heat exchange
- condenser
- 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 - Fee Related
Links
Description
【０００１】
【発明の属する技術分野】
本発明、不純物含有の液体酸素を超高純度に精製することのできる液体酸素精製方法およびそれに用いる装置に関するものである。
【０００２】
【従来の技術】
一般に、空気分離装置で製造される液体酸素（ＬＯ2 ）には、不純物として、Ｎ2 ：２０ｐｐｍ，Ａｒ：１０００ｐｐｍ，ＣＯ：０．１ｐｐｍ，Ｃn Ｈm ：１５ｐｐｍ程度が含まれており、これら不純物は、半導体最先端工場において悪影響を及ぼすため厳しい規制がなされている。
【０００３】
そこで、液体酸素を超高純度に精製するものとして、特開平２−１５０６８６号公報に示す超高純度酸素製造装置が提案されている。この装置では、まず微量不純物を含む液体酸素（純度９９．６〜９９．９％）を第１精留塔に導入し、この第１精留塔で精留を行い、排出する少量の酸素ガス中に、酸素に比べて低沸点成分である窒素，一酸化炭素，アルゴン等の不純物を含有させて分離し、つぎに大部分の酸素を液体状態で第１精留塔の下部から取り出して第２精留塔に導入し、この第２精留塔で精留を行い、排出する少量の液体酸素中に、酸素に比べて高沸点成分であるクリプトン，キセノン，Ｃn Ｈm 等の不純物を含有させて分離し、大部分の酸素ガスを第２精留塔の塔頂部のコンデンサに通して液体状態で取り出している。
【０００４】
【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、液体酸素中の窒素，一酸化炭素，アルゴン等の不純物を全て第１精留塔で気化させて分離除去することができず、第１精留塔の下部に溜まる液体酸素中には上記不純物の一部が残存する。また、第２精留塔では上記の窒素，一酸化炭素，アルゴン等の不純物を除去しないため、第２精留塔から取り出す液体酸素中には、上記残存不純物のモル分率に相当する不純物が液体状態で存在する。したがって、上記の装置では、不純物濃度がｐｐｍオーダーとなり、ｐｐｂオーダーの製品を得ることは不可能であった。
【０００５】
本発明は、このような事情に鑑みなされたもので、不純物濃度をｐｐｂオーダーにすることのできる液体酸素精製方法およびそれに用いる装置の提供をその目的とする。
【０００６】
【課題を解決するための手段】
上記の目的を達成するため、本発明は、原料液体酸素を第１精留塔に導入し、上記第１精留塔に酸素より高沸点成分を液体のまま溜め、酸素より低沸点成分を気化して酸素ガスとともに取り出し、この取り出した低沸点成分および酸素ガスを第２精留塔に導入し、この第２精留塔で上記低沸点成分と酸素を分離して高純度化し、この高純度酸素ガスを液化して溜め、この溜められた高純度液体酸素を製品液体酸素として取り出すようにし、液体酸素の冷熱で液化する熱交換用気体を圧縮機で圧縮したのち、その一部と、第１精留塔に溜まり酸素より高沸点成分を含有する液体酸素とを熱交換させて、第１精留塔に溜まる液体酸素を気化させるとともに熱交換用気体を液化させ、この液化させた熱交換用気体を第１凝縮器の寒冷として用い、第１精留塔に滞留する酸素ガスを第１凝縮器で液化し還流液として第１精留塔に戻し、第１凝縮器で寒冷としての作用を終えて気化した熱交換用気体をバッファタンクを経由して上記圧縮機に戻すようにし、一方、上記圧縮機で圧縮された熱交換用気体の残部と、第２精留塔に溜まる高純度液体酸素とを熱交換させて、この高純度液体酸素を気化させるとともに熱交換用気体を液化させ、この液化させた熱交換用気体を第２凝縮器の寒冷として用い、第２精留塔に滞留する酸素ガスを第２凝縮器で液化し還流液として第２精留塔に戻し、第２凝縮器で寒冷としての作用を終えて気化した熱交換用気体を上記バッファタンクに導入し、これを経由して、第１凝縮器で寒冷としての作用を終えて気化した熱交換用気体とともに上記圧縮機に戻し、上記バッファタンクに、熱交換用気体を補給する補給パイプを設け、この補給パイプに設けた圧力調節弁で上記バッファタンク内の圧力を検出し、その検出結果に基づき上記圧力を一定に保つように構成した液体酸素精製方法を第１の要旨とし、原料液体酸素導入路と、原料液体酸素導入路からの原料液体酸素を導入し酸素より高沸点成分を液体のまま溜め酸素より低沸点成分を気化して酸素ガスとともに取り出す第１精留塔と、上記第１精留塔から取り出した酸素ガスおよび上記低沸点成分を第２精留塔に導入する導入路と、上記低沸点成分と酸素を分離して高純度化しこの高純度酸素ガスを液化して溜めこの高純度液体酸素を製品液体酸素として取り出す第２精留塔と、第１精留塔の上部に設けた還流液生成用の第１凝縮器と、第１精留塔の下部に設けた液体酸素気化用の第１加熱器と、第２精留塔の上部に設けた還流液生成用の第２凝縮器と、第２精留塔の下部に設けた高純度液体酸素気化用の第２加熱器と、液体酸素の冷熱で液化する熱交換用気体を圧縮したのちその一部を第１加熱器に供給しその残部を第２加熱器に供給する圧縮機と、第１加熱器で液化された熱交換用気体を寒冷として第１凝縮器に導入するパイプと、第２加熱器で液化された熱交換用気体を寒冷として第２凝縮器に導入するパイプと、第１凝縮器で寒冷としての作用を終えて気化した熱交換用気体を上記圧縮機に戻すパイプと、第２凝縮器で寒冷としての作用を終えて気化した熱交換用気体を上記圧縮機に戻すパイプとを備え、第１凝縮器で寒冷としての作用を終えて気化した熱交換用気体をバッファタンクを経由して上記圧縮機に戻し、第２凝縮器で寒冷としての作用を終えて気化した熱交換用気体を上記バッファタンクに導入し、これを経由して、第１凝縮器で寒冷としての作用を終えて気化した熱交換用気体とともに上記圧縮機に戻すように構成し、上記バッファタンクに、熱交換用気体を補給する補給パイプを設け、この補給パイプに設けた圧力調節弁で上記バッファタンク内の圧力を検出し、その検出結果に基づき上記圧力を一定に保つように構成した液体酸素精製装置を第２の要旨とする。
【０００７】
すなわち、本発明の液体酸素精製方法は、原料液体酸素を第１精留塔に導入してこの第１精留塔から酸素および酸素より低沸点成分を気体状態で取り出すことにより、第１精留塔で酸素より高沸点成分を液体状態で分離除去し、つぎに第１精留塔から取り出した酸素および酸素より低沸点成分を気体状態で第２精留塔に導入し、この第２精留塔で酸素より低沸点成分と酸素とを分離している。これにより、第２精留塔に溜まる液体酸素が高純度になり、この高純度な液体酸素を製品として取り出すことができる。このように、第２精留塔に気体状態で酸素および酸素より低沸点成分を導入した場合には、酸素を再液化させることによる効果のため、液体酸素中には殆ど酸素より低沸点成分が含まれなくなる。したがって、第２精留塔で得られる液体は、不純物濃度がｐｐｂオーダーの超高純度な液体酸素となる。一方、本発明の装置によれば、上記方法の実現が容易になり、効率よく液体酸素の精製が行える。
【０００８】
また、本発明の方法では、液体酸素の冷熱で液化する熱交換用気体と第１精留塔に溜まり酸素より高沸点成分を含有する液体酸素とを熱交換させて、第１精留塔に溜まる液体酸素を蒸発させるとともに熱交換用気体を液化させ、この液化させた熱交換用気体を第１凝縮器の寒冷として用い、第１精留塔に滞留する酸素ガスを上記第１凝縮器で液化し還流液として第１精留塔に戻すようにしたため、また、液体酸素の冷熱で液化する熱交換用気体と第２精留塔に溜まる高純度液体酸素とを熱交換させて、高純度液体酸素を蒸発させるとともに熱交換用気体を液化させ、この液化した熱交換用気体を第２凝縮器の寒冷として用い、第２精留塔に滞留する酸素ガスを上記第２凝縮器で液化し還流液として第２精留塔に戻すようにしたため、外部からの寒冷や熱源は不要となる。
【０００９】
また、本発明の方法では、熱交換用気体を圧縮機で圧縮したのち第１精留塔に溜まる液体酸素と熱交換させ、第１凝縮器の寒冷としての作用を終えて気化した熱交換用気体を上記圧縮機に戻すようにしたため、また、熱交換用気体を圧縮機で圧縮したのち第２精留塔に溜まる高純度液体酸素と熱交換させ、第２凝縮器の寒冷としての作用を終えて気化した熱交換用気体を上記圧縮機に戻すようにしたため、熱交換用気体を外部から導入する必要はない。
【００１０】
【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。
【００１１】
図１は本発明の液体酸素精製装置の一実施の形態の構成図を示している。図において、１は原料タンクであり、内部に原料液体酸素（原料ＬＯ2 ）が収容されている。この原料ＬＯ2 は、従来の深冷空気分離装置により製造されたものであり、不純物として、Ｎ2 ：２０ｐｐｍ，Ａｒ：１０００ｐｐｍ，ＣＯ：０．１ｐｐｍ，Ｃn Ｈm ：１５ｐｐｍ等が含まれている。２は第１精留塔であり、その下部から、原料タンク１内の原料ＬＯ2 が供給パイプ７を経て送り込まれる。第１精留塔２内では、送り込まれた原料ＬＯ2 のうち、Ｏ2 やＯ2 （沸点−１８３℃）より低沸点成分であるＮ2 （沸点−１９６℃），Ａｒ（沸点−１８６℃），ＣＯ（沸点−２０５℃）等が第１加熱器３によりガス化して第１精留塔２内を上昇し、Ｏ2 とともに上部に滞留する。また、Ｏ2 およびＯ2 より高沸点成分であるＣＨ4 （沸点−１６１℃）等が液体のまま第１精留塔２の底部に溜まる。７ａは供給パイプ７に設けた液面調節弁であり、液面計（図示せず）による第１精留塔２底部の貯留液体酸素（貯留ＬＯ2 ）６の液面高さの検出結果に基づき、供給パイプ７を通る原料ＬＯ2 の流量を調節し、上記貯留ＬＯ2 ６の液面高さを一定に保持する作用をする。
【００１２】
３は第１加熱器であり、第１精留塔２の下部に設けられている。この第１加熱器３には、圧縮機１０で圧縮されたＮ2 ガス（熱交換用気体）がアフタークーラー１１，送給パイプ１３，第１分岐送給パイプ１４ａ，主熱交換器１２を経て液化温度近くまで冷却され、送り込まれる。このＮ2 ガスは、第１精留塔２の底部に溜まる貯留ＬＯ2 ６を加温し、Ｏ2 およびＮ2 ，Ａｒ，ＣＯ等の低沸点成分を気化して第１精留塔２の上部に滞留させ、ＣＨ4 等の高沸点成分を液体のまま残して貯留ＬＯ2 ６中に濃縮させる。一方、それ自身は貯留ＬＯ2 ６の冷熱により液化されて第１導入パイプ９に導入され、その一部が第１分岐導入パイプ９ａを経て第１蒸発器４に送入され、他部が第２分岐導入パイプ９ｂを経て第２蒸発器２４に送入される。上記第１蒸発器４の内部は、膨張し送入された液体窒素（ＬＮ2 ）によりＯ2 ガスの沸点以下の温度に冷却される。一方、第１精留塔２の上部に滞留するＯ2 ガスは、その一部が第１還流液パイプ８ａを経て第１蒸発器４内の第１凝縮器５に送入される。上記冷却により、第１凝縮器５内に送入されたＯ2 ガスが液化して還流液となり第２還流液パイプ８ｂから第１精留塔２の上部に流下する。
【００１３】
１５はＬＯ2 排出パイプであり、第１精留塔２底部に溜まる貯留ＬＯ2 ６（不純物として、Ｎ2 ：５．３ｐｐｍ，Ａｒ：６２５ｐｐｍ，ＣＯ：０．０４ｐｐｍ，Ｃn Ｈm ：３７５ｐｐｍ等が含まれている）を主熱交換器１２に送り、ここを通る（圧縮機１０からの）Ｎ2 ガスと熱交換させて、貯留ＬＯ2 ６を常温近くまで加温してガス化させ外部に放出する。１５ａはＬＯ2 排出パイプ１５の主熱交換器１２下流部分に設けた流量調節弁であり、流量計（図示せず）によるＬＯ2 排出パイプ１５内のＯ2 ガスの流量の検出結果に基づき、このＯ2 ガスの流量を調節する作用をする。この実施の形態では、ＬＯ2 排出パイプ１５による貯留ＬＯ2 ６の排出量を、後述する導出パイプ１９の流量の約４％に調節しており、Ｃn Ｈm が高く濃縮するのを防いでいる。１６は第１分岐導入パイプ９ａに設けた流量調節弁であり、第１分岐導入パイプ９ａを通るＬＮ2 の流量を調節している。１７は第２分岐導入パイプ９ｂに設けた流量調節弁であり、第２分岐導入パイプ９ｂを通るＬＮ2 の流量を調節する作用をする。
【００１４】
１９は導出パイプであり、上記第１精留塔２の上部空間のＯ2 ガス（不純物として、Ｎ2 ：２１ｐｐｍ，Ａｒ：１０１６ｐｐｍ，ＣＯ：０．１ｐｐｍ等が含まれている）を導出して第２精留塔２０に送り込む。第２精留塔２０内では、送り込まれたＯ2 ガスのうち、Ｎ2 ，Ａｒ，ＣＯ等の低沸点成分が気体のまま上昇し上部に滞留する。また、Ｏ2 ガスが液化して下降し底部に溜まる。１９ａは導出パイプ１９に設けた流量調節弁であり、流量計（図示せず）による導出パイプ１９内のＯ2 ガスの流量の検出結果に基づき、このＯ2 ガスの流量を調節する作用をする。
【００１５】
２１は第２加熱器であり、第２精留塔２０の底部に設けられている。この第２加熱器２１には、圧縮機１０で圧縮されたＮ2 ガスがアフタークーラー１１，送給パイプ１３，第２分岐送給パイプ１４ｂ，主熱交換器１２を経て液化温度近くまで冷却され、送り込まれる。このＮ2 ガスは、第２精留塔２０の底部に溜まる貯留ＬＯ2 ２２を加温し、Ｏ2 ガスを気化して上部に滞留させ、貯留ＬＯ2 ２２を超高純度にする。一方、それ自身は貯留ＬＯ2 ２２の冷熱によって液化し、第２導入パイプ２３を経て第２蒸発器２４に送入される。この第２蒸発器２４の内部は、第２分岐導入パイプ９ｂを経て膨張し送入されたＬＮ2 および第２導入パイプ２３を経て膨張し送入されたＬＮ2 でＯ2 ガスの沸点以下の温度に冷却される。一方、第２精留塔２０の上部空間のＯ2 ガスは、その一部が第３還流液パイプ２５ａを経て第２蒸発器２４内の第２凝縮器２６に送入される。上記冷却により、第２凝縮器２６内に送入されたＯ2 ガスが液化して還流液となり、第４還流液パイプ２５ｂから第２精留塔２０の上部に流下する。２３ａは第２導入パイプ２３を通るＬＮ2 の流量を調節する流量調節弁である。
【００１６】
２７はＯ2 ガス取出パイプであり、第２精留塔２０の上部空間に滞留するＯ2 ガス（不純物として、Ｎ2 ：１８０ｐｐｍ，Ａｒ：８８６３ｐｐｍ，ＣＯ：０．８６ｐｐｍ等が含まれている）を主熱交換器１２に送り、ここを通る（圧縮機１０からの）Ｎ2 ガスと熱交換させて、Ｏ2 ガスを常温に昇温して外部に放出する。２７ａはＯ2 ガス取出パイプ２７の主熱交換器１２下流部分に設けた流量調節弁であり、流量計（図示せず）によるＯ2 ガス取出パイプ２７内のＯ2 ガスの流量の検出結果に基づき、このＯ2 ガスの流量を調節する作用をする。２８は製品ＬＯ2 取出パイプであり、第２精留塔２０の底部の超高純度な貯留ＬＯ2 ２２を製品ＬＯ2 として取り出し製品タンク２９に導入する。２８ａは製品ＬＯ2 取出パイプ２８に設けた液面調節弁であり、液面計（図示せず）による第２精留塔２０底部の貯留ＬＯ2 ２２の液面高さの検出結果に基づき、製品ＬＯ2 取出パイプ２８を通る貯留ＬＯ2 ２２の流量を調節し、上記貯留ＬＯ2 ２２の液面高さを一定に保持する作用をする。
【００１７】
３３は第１蒸発器４上部から延びる第１Ｎ2 ガス取出パイプであり、第１蒸発器４の上部空間に溜まるＮ2 ガス（第１蒸発器４内に送り込まれたＬＮ2 が第１凝縮器５内を通るＯ2 ガスで気化されて上部空間に溜まったもの）を主熱交換器１２に送り、ここを通る（圧縮機１０からの）Ｎ2 ガスと熱交換させてＮ2 ガスを常温に昇温し、取出パイプ３５を経て第１バッファタンク３０に送る。３３ａは第１Ｎ2 ガス取出パイプ３３の主熱交換器１２下流部分に設けた圧力調節弁であり、圧力計（図示せず）による第１蒸発器４の上部空間の内圧の検出結果に基づき、第１Ｎ2 ガス取出パイプ３３を通るＮ2 ガスの流量を調節し、上記内圧を一定に保持する作用をする。３４は第２蒸発器２４上部から延びる第２Ｎ2 ガス取出パイプであり、第２蒸発器２４の上部空間に溜まるＮ2 ガス（第２蒸発器２４内に送り込まれたＬＮ2 が第２凝縮器２６内を通るＯ2 ガスで気化されて上部空間に溜まったもの）を主熱交換器１２に送り、ここを通る（圧縮機１０からの）Ｎ2 ガスと熱交換させてＮ2 ガスを常温に昇温し、取出パイプ３５を経て第１バッファタンク３０に送る。３４ａは第２Ｎ2 ガス取出パイプ３４の主熱交換器１２下流部分に設けた圧力調節弁であり、圧力計（図示せず）による第２蒸発器２４の上部空間の内圧の検出結果に基づき、第２Ｎ2 ガス取出パイプ３４を通るＮ2 ガスの流量を調節し、上記内圧を一定に保持する作用をする。
【００１８】
３６はＮ2 ガスを第１バッファタンク３０に補給する補給パイプである。３７は第１バッファタンク３０を第２バッファタンク３１に連通する連通パイプである。第１バッファタンク３０は補給パイプ３６に設けられており、第２バッファタンク３１は送給パイプ１３に設けられている。第１バッファタンク３０は、取出パイプ３５を経て送られたＮ2 ガスと補給パイプ３６を通るＮ2 ガスとを合流させて緩衝させる作用をする。第２バッファタンク３１は、連通パイプ３７を経て送られたＮ2 ガスと送給パイプ１３を通るＮ2 ガスとを合流させて緩衝させる作用をする。３６ａは補給パイプ３６に設けた圧力調節弁であり、第１バッファタンク３０内の圧力の検出結果に基づき、圧力を一定に保つ作用をする。３７ａは連通パイプ３７に設けた圧力調節弁であり、第２バッファタンク３１内の圧力の検出結果に基づき、圧力を一定に保つ作用をする。４０は真空パーライト断熱箱であり、内部に原料タンク１、両精留塔２，２０、両凝縮蒸発器４，２４、主熱交換器１２および製品タンク２９が収容されている。この真空パーライト断熱箱４０の内部は真空状態に保持されており、かつパーライト（図示せず）が充填されている。
【００１９】
この装置を用い、例えばつぎのようにしてＬＯ2 を超高純度ＬＯ2 に精製することができる。すなわち、まず、原料タンク１から原料ＬＯ2 を供給パイプ７を経て第１精留塔２の下部に導入し、第１精留塔２内で主にＯ2 やＣＨ4 等の高沸点成分を液体のまま底部に溜める。上記原料ＬＯ2 の導入量は液面調節弁７ａで自動的に制御され、これにより、第１精留塔２の底部に溜まる貯留ＬＯ2 ６の液面が一定に保持される。ついで、圧縮機１０で加圧したＮ2 ガスをアフタークーラー１１，主熱交換器１２を経て第１精留塔２の底部の第１加熱器３に一定量を送り込む。このＮ2 ガスで第１精留塔２の底部の貯留ＬＯ2 ６は気化し、Ｏ2 ガスとなり、Ｎ2 ，Ａｒ，ＣＯ等の低沸点成分とともに上昇し上部に滞留する。また、ＣＨ4 等の高沸点成分が貯留ＬＯ2 ６に残り濃縮する。一方、第１加熱器３内で液化したＬＮ2 を第１導入パイプ９に導出し、その一部を第１分岐導入パイプ９ａを経て第１蒸発器４内に送り込み、第１凝縮器５の寒冷用として用いる。つぎに、第１精留塔２の上部に滞留するＯ2 ガスの一部を第１還流液パイプ８ａを経て第１凝縮器５に送り込み、ここで上記寒冷によって液化し、還流液として第１精留塔２に戻す。そして、この還流液を第１精留塔２内を流下させ、上昇するＯ2 ガスと向流接触させて精留し、Ｏ2 ガス中のＣＨ4 等の高沸点成分を液化させ、Ｏ2 ガスやＮ2 ，Ａｒ，ＣＯ等の低沸点成分等を気体として上部に滞留させる。このようにして、ＣＨ4 等の高沸点成分を略完全に除去したＯ2 ガスを導出パイプ１９から取り出して第２精留塔２０に送り込み、一方、第１精留塔２底部に溜まる貯留ＬＯ2 ６の約４％程度をＬＯ2 排出パイプ１５により排出する。
【００２０】
第２精留塔２０では、送り込まれたＯ2 ガスのうち、Ｎ2 ，Ａｒ，ＣＯ等の低沸点成分を上昇させて上部に滞留させ、高沸点成分であるＯ2 ガス等を液化して下降させ第２精留塔２０の底部に溜める。つぎに、圧縮機１０で加圧したＮ2 ガスをアフタークーラー１１，主熱交換器１２を経て第２精留塔２０の底部の第２加熱器２１に一定量を送り込む。このＮ2 ガスで第２精留塔２０底部の貯留ＬＯ2 ２２を気化させることにより、Ｎ2 ，Ａｒ，ＣＯ等の低沸点成分が略完全に除去される。
【００２１】
一方、第２加熱器２１内で液化したＬＮ 2 を第２導入パイプ２３を経て第２蒸発器２４内に送り込み、第２凝縮器２６の寒冷用として用いる。また、第１加熱器３内で液化したＬＮ 2 を第２分岐導入パイプ９ｂを経て第２蒸発器２４内に送り込み、第２凝縮器２６の寒冷用として用いる。そして、第２精留塔２０の上部に滞留するＯ 2 ガスを第３還流液パイプ２５ａを経て第２凝縮器２６に送り込み、ここで上記寒冷によって液化し、還流液として第２精留塔２０に戻す。そして、この還流液を第２精留塔２０内を流下させ、上昇するＯ 2 ガスと向流接触させて精留し、Ｏ 2 ガスを液化させ、Ｎ 2 ，Ａｒ，ＣＯ等の低沸点成分を気体として上部に滞留濃縮させる。この濃縮量を決定する主要因は原料ＬＯ 2 と第２精留塔２０上部からＯ 2 ガス取り出しパイプ２７により排出するＯ 2 ガスとの比であり、この実施の形態では、原料ＬＯ 2 の約１１％を排出している。
【００２２】
このようにして得られた超高純度な（不純物濃度がｐｐｂオーダーの）貯留ＬＯ 2 ２２を、その液面を一定にコントロールするようにして、製品ＬＯ 2 取出パイプ２８から製品として自動的に取り出す。
【００２３】
一方、第１および第２蒸発器４，２４から排出した低温Ｎ 2 ガスを主熱交換器１２に通し、ここを通る（圧縮機１０からの）Ｎ 2 ガスと熱交換させてＮ 2 ガスを液化温度近くまで冷却し、それ自体を常温近くまで加温して圧縮機１０に送り、この圧縮機１０で加圧して再度主熱交換器１２に送り込む。このように、Ｎ 2 ガスは循環サイクルを形成している。
【００２４】
上記のように、この実施の形態では、不純物濃度がｐｐｂオーダーの超高純度ＬＯ 2 を得ることができる。
【００２５】
しかも、超高純度ＬＯ 2 製造量は第１精留塔２から第２精留塔２０へ供給されるＯ 2 ガスの流量のみで決定されるため、ＬＯ 2 等の流量測定が困難であった従来の液体の流量測定が不要となり、運転が非常に簡素化されるとともに、信頼性がアップする。
【００２６】
図２は本発明の液体酸素精製装置の他の実施の形態の構成図を示している。この実施の形態では、図１に示す実施の形態における、第１蒸発器４を第２蒸発器２４で兼用している。このため、この実施の形態では、第１蒸発器４，第１導入パイプ９，第１分岐導入パイプ９ａ，第２分岐導入パイプ９ｂ，第１Ｎ2 ガス取出パイプ３３を無くし、第２蒸発器２４内に第１凝縮器５を配設している。また、第１および第２の凝縮器５，２６を第２蒸発器２４に連結する導入パイプ５０および流量調節弁５０ａを設けている。それ以外の部分は図１に示す実施の形態と同様であり、同様の部分には同じ符号を付している。また、この実施の形態でも、図１に示す実施の形態と同様の作用・効果を奏する。
【００２７】
【発明の効果】
以上のように、本発明の液体酸素精製方法によれば、第１精留塔で原料液体酸素中の酸素および酸素より低沸点成分を気体状態で取り出し、第２精留塔の原料としているため、第２精留塔で得られる液体中には酸素より低沸点成分が液化して混入していることは殆どない。したがって、第２精留塔で得られる液体は、不純物濃度がｐｐｂオーダーの超高純度な液体酸素となる。一方、本発明の装置によれば、上記方法の実現が容易になり、効率よく液体酸素の精製が行える。
【図面の簡単な説明】
【図１】本発明の一実施の形態を示す液体酸素精製装置の構成図である。
【図２】本発明の他の実施の形態を示す液体酸素精製装置の構成図である。
【符号の説明】
２ 第１精留塔
２０ 第２精留塔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid oxygen purification method and an apparatus used therefor, which can purify impurity-containing liquid oxygen to ultrahigh purity.
[0002]
[Prior art]
In general, liquid oxygen (LO 2 ) produced by an air separation device contains impurities such as N 2 : 20 ppm, Ar: 1000 ppm, CO: 0.1 ppm, C n H m : 15 ppm. Impurities are adversely affected at cutting-edge semiconductor factories, and are therefore strictly regulated.
[0003]
Therefore, as an apparatus for purifying liquid oxygen to ultrahigh purity, an ultrahigh purity oxygen production apparatus disclosed in JP-A-2-150686 has been proposed. In this apparatus, first, liquid oxygen (purity: 99.6 to 99.9%) containing a small amount of impurities is introduced into the first rectification column, rectification is performed in the first rectification column, and a small amount of oxygen gas is discharged. It contains and separates impurities such as nitrogen, carbon monoxide, and argon, which are components having a lower boiling point than oxygen, and then most of the oxygen is taken out from the lower part of the first rectification column in a liquid state. 2 Introduce into the rectification column, perform rectification in the second rectification column, and discharge impurities such as krypton, xenon and C n H m that are higher boiling point components than oxygen into the small amount of liquid oxygen discharged. The majority of the oxygen gas is taken out in a liquid state through a condenser at the top of the second rectifying column.
[0004]
[Problems to be solved by the invention]
However, in the above apparatus, impurities such as nitrogen, carbon monoxide, and argon in the liquid oxygen cannot be all separated and removed by vaporization in the first rectification column, and the liquid collected in the lower portion of the first rectification column. Part of the impurities remains in oxygen. In addition, since impurities such as nitrogen, carbon monoxide, and argon are not removed in the second rectifying column, impurities corresponding to the molar fraction of the remaining impurities are present in the liquid oxygen extracted from the second rectifying column. Exists in a liquid state. Therefore, in the above apparatus, the impurity concentration is in the order of ppm, and it is impossible to obtain a product in the ppb order.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid oxygen purification method capable of setting the impurity concentration to the ppb order and an apparatus used therefor.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention introduces raw liquid oxygen into a first rectifying column, stores a component having a higher boiling point than oxygen in the first rectifying column as a liquid, and removes a component having a lower boiling point from oxygen. The low boiling point component and oxygen gas taken out are introduced into the second rectifying column, and the low boiling point component and oxygen are separated and purified in this second rectifying column. Oxygen gas is liquefied and stored, and the stored high-purity liquid oxygen is taken out as product liquid oxygen, and the heat exchange gas that is liquefied by the cold heat of liquid oxygen is compressed by a compressor. Heat exchange with liquid oxygen that has a boiling point component higher than oxygen accumulated in one rectification column vaporizes the liquid oxygen collected in the first rectification column and liquefies the heat exchange gas, and this liquefied heat exchange Use the gas for the cooling of the first condenser, Oxygen gas staying in the rectification column first returned to the rectification column as liquefied reflux in the first condenser, the heat exchange gas vaporized finishing action as cold in the first condenser via a buffer tank and then returned to the compressor, while the remainder of the heat exchange gas compressed by the compressor, and a high purity liquid oxygen collected in the second rectification column by heat exchange, the high purity liquid oxygen And the heat exchange gas is liquefied, and the liquefied heat exchange gas is used as the cooling temperature of the second condenser, and the oxygen gas staying in the second rectifying column is liquefied by the second condenser and refluxed. To the second rectification column, the gas for heat exchange vaporized after the action of the second condenser as a cold is introduced into the buffer tank, and the action of the first condenser as the cold through this it returns to the compressor with a heat exchange gas vaporized finishing, on A buffer tank, a replenishing pipe for replenishing a gas heat exchanger arranged to detect the pressure of the buffer tank by the pressure regulating valve provided in the supply pipe, configured to maintain the pressure on the basis of the detection result to the constant The liquid oxygen refining method is the first gist, and the raw liquid oxygen is introduced from the raw liquid oxygen introducing passage and the raw liquid oxygen introducing passage, and the high boiling point component is stored as a liquid while the low boiling point component is vaporized from oxygen. A first rectifying column taken out together with oxygen gas, an introduction path for introducing the oxygen gas taken out from the first rectifying column and the low boiling point component into the second rectifying column, and the low boiling point component and oxygen are separated. The second rectifying column for liquefying and storing the high-purity oxygen gas and collecting the high-purity liquid oxygen as product liquid oxygen, and the first condensing for generating the reflux liquid provided at the upper portion of the first rectifying column. And the first rectification tower A first heater for vaporizing liquid oxygen provided in the lower part, a second condenser for producing a reflux liquid provided in the upper part of the second rectifying column, and a high-purity liquid oxygen provided in the lower part of the second rectifying column A second heater for vaporization, a compressor for compressing a heat exchange gas liquefied by the cold of liquid oxygen, supplying a part thereof to the first heater and supplying the remainder to the second heater, A pipe for introducing the heat exchange gas liquefied in the first heater into the first condenser as cold; a pipe for introducing the heat exchange gas liquefied in the second heater into the second condenser as cold; A pipe for returning the vaporized heat exchange gas after the action as cold in one condenser to the compressor and a heat exchange gas vaporized after the action as cold in the second condenser are returned to the compressor. and a pipe, a heat exchange gas vaporized finishing action as cold in the first condenser Baffata The heat exchange gas that has been vaporized after the action of cooling in the second condenser is introduced into the buffer tank via the second condenser, and is cooled in the first condenser via this. The buffer tank is provided with a replenishment pipe for replenishing the heat exchange gas, and the pressure control valve provided on the replenishment pipe provides the above A liquid oxygen purification apparatus configured to detect the pressure in the buffer tank and keep the pressure constant based on the detection result is a second gist.
[0007]
That is, in the liquid oxygen purification method of the present invention, the raw liquefied oxygen is introduced into the first rectification column, and oxygen and a component having a lower boiling point than oxygen are taken out from the first rectification column in a gas state. In the column, high boiling components from oxygen are separated and removed in a liquid state, and then oxygen extracted from the first rectifying column and components having lower boiling points than oxygen are introduced into the second rectifying column in a gaseous state. The tower separates the low-boiling components and oxygen from oxygen. Thereby, the liquid oxygen which accumulates in the 2nd fractionator becomes high purity, and this high purity liquid oxygen can be taken out as a product. Thus, when oxygen and a low-boiling component lower than oxygen are introduced into the second rectification column in a gaseous state, the liquid oxygen contains almost no lower-boiling component than oxygen due to the effect of reliquefying oxygen. It will not be included. Therefore, the liquid obtained in the second rectification column becomes ultrahigh-purity liquid oxygen having an impurity concentration of ppb order. On the other hand, according to the apparatus of the present invention, the above method can be easily realized, and liquid oxygen can be purified efficiently.
[0008]
In the method of the present invention, the heat exchange gas that is liquefied by the cold heat of liquid oxygen and the liquid oxygen that is stored in the first rectification column and that contains a component having a boiling point higher than oxygen are heat-exchanged to the first rectification column. The liquid oxygen that accumulates is evaporated and the heat exchange gas is liquefied, and the liquefied heat exchange gas is used as the cooling of the first condenser, and the oxygen gas that is retained in the first rectification tower is used in the first condenser. since the so liquefied returned to the first rectification column as a reflux liquid, also the high purity liquid oxygen collected in the heat exchange gas and a second rectification column to liquefy at cold of liquid oxygen is heat exchanged, high The liquid oxygen is evaporated and the heat exchange gas is liquefied. The liquefied heat exchange gas is used as the cooling temperature of the second condenser, and the oxygen gas staying in the second rectifying column is liquefied by the second condenser. because the refluxing solution was returned to the second rectification column, from the outside Cold and heat source is not required.
[0009]
In the method of the present invention, the heat exchange gas is compressed by the compressor and then exchanged with the liquid oxygen accumulated in the first rectification column. After the action as the cold of the first condenser is completed, the heat exchange gas is vaporized. because gas was returned to the compressor, also a gas heat exchanger high purity liquid oxygen is heat exchanged accumulated in the second rectification column after compressed by the compressor, it acts as a refrigeration second condenser since you returned to the compressor vaporized heat exchange gas finishing, it is not necessary to introduce a gas heat exchanger from the outside.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows a configuration diagram of an embodiment of a liquid oxygen purification apparatus of the present invention. In the figure, reference numeral 1 denotes a raw material tank, in which raw material liquid oxygen (raw material LO 2 ) is accommodated. This raw material LO 2 is produced by a conventional cryogenic air separation device, and impurities include N 2 : 20 ppm, Ar: 1000 ppm, CO: 0.1 ppm, C n H m : 15 ppm, and the like. Yes. Reference numeral 2 denotes a first rectification tower, from which a raw material LO 2 in the raw material tank 1 is fed through a supply pipe 7. In the first rectification tower 2, N 2 (boiling point-196 ° C.) and Ar (boiling point-186 ° C.) which are lower boiling components than O 2 and O 2 (boiling point-183 ° C.) of the raw material LO 2 fed. ), CO (boiling point -205 ° C.) and the like are gasified by the first heater 3 and rise in the first rectifying column 2 and stay in the upper part together with O 2 . Further, O 4 and CH 4 (boiling point −161 ° C.), which is a component having a higher boiling point than O 2 , remain in the bottom of the first rectifying column 2 in a liquid state. Reference numeral 7a denotes a liquid level control valve provided in the supply pipe 7. The liquid level control valve 7a detects the liquid level height of the stored liquid oxygen (stored LO 2 ) 6 at the bottom of the first fractionator 2 by a liquid level gauge (not shown). Based on this, the flow rate of the raw material LO 2 passing through the supply pipe 7 is adjusted, and the liquid level of the storage LO 2 6 is kept constant.
[0012]
3 is a 1st heater, and is provided in the lower part of the 1st rectification tower 2. As shown in FIG. In the first heater 3, N 2 gas (heat exchange gas) compressed by the compressor 10 passes through the aftercooler 11, the supply pipe 13, the first branch supply pipe 14 a, and the main heat exchanger 12. Cooled to near liquefaction temperature and fed. The N 2 gas warms the stored LO 2 6 accumulated at the bottom of the first rectifying column 2 and vaporizes low boiling components such as O 2 and N 2 , Ar, CO, etc. It is allowed to stay in the upper part, and the high boiling point component such as CH 4 is left in a liquid state and concentrated in the stored LO 2 6. On the other hand, it is liquefied by the cold heat of the stored LO 2 6 and introduced into the first introduction pipe 9, a part of which is sent to the first evaporator 4 through the first branch introduction pipe 9 a, and the other part is the first. It is fed into the second evaporator 24 through the two-branch introduction pipe 9b. The inside of the first evaporator 4 is cooled to a temperature below the boiling point of the O 2 gas by liquid nitrogen (LN 2 ) expanded and fed. On the other hand, a part of the O 2 gas staying in the upper part of the first rectifying column 2 is sent to the first condenser 5 in the first evaporator 4 through the first reflux liquid pipe 8a. By the cooling, the O 2 gas sent into the first condenser 5 is liquefied to become a reflux liquid, and flows down from the second reflux liquid pipe 8b to the upper portion of the first rectifying column 2.
[0013]
Reference numeral 15 denotes an LO 2 discharge pipe, and stored LO 2 6 collected at the bottom of the first rectification column 2 (as impurities, N 2 : 5.3 ppm, Ar: 625 ppm, CO: 0.04 ppm, C n H m : 375 ppm, etc. Is transferred to the main heat exchanger 12 and heat-exchanged with N 2 gas (from the compressor 10) passing through the main heat exchanger 12 to heat the stored LO 2 6 to near normal temperature and gasify it. To release. 15a is a flow regulating valve provided on the main heat exchanger 12 downstream portion of the LO 2 discharge pipe 15, on the basis of the O 2 gas flow rate detection result of the flow meter LO 2 discharge pipe 15 by (not shown), The O 2 gas flow rate is adjusted. In this embodiment, the discharge amount of the stored LO 2 6 by the LO 2 discharge pipe 15 is adjusted to about 4% of the flow rate of the outlet pipe 19 to be described later, so that C n H m is prevented from being concentrated high. Yes. Reference numeral 16 denotes a flow rate adjusting valve provided in the first branch introduction pipe 9a, which regulates the flow rate of LN 2 passing through the first branch introduction pipe 9a. Reference numeral 17 denotes a flow rate adjusting valve provided in the second branch introduction pipe 9b, which acts to adjust the flow rate of LN 2 passing through the second branch introduction pipe 9b.
[0014]
Reference numeral 19 denotes a lead-out pipe that leads out the O 2 gas in the upper space of the first rectifying column 2 (impurities include N 2 : 21 ppm, Ar: 1016 ppm, CO: 0.1 ppm, etc.). It is sent to the second rectification tower 20. In the second rectifying column 20, low-boiling components such as N 2 , Ar, and CO out of the fed O 2 gas rise as they are and stay in the upper part. Also, the O 2 gas liquefies and descends and accumulates at the bottom. Reference numeral 19a denotes a flow rate adjusting valve provided on the outlet pipe 19, which operates to adjust the flow rate of the O 2 gas based on the detection result of the flow rate of O 2 gas in the outlet pipe 19 by a flow meter (not shown). .
[0015]
Reference numeral 21 denotes a second heater, which is provided at the bottom of the second rectifying column 20. In the second heater 21, the N 2 gas compressed by the compressor 10 is cooled to near the liquefaction temperature via the aftercooler 11, the supply pipe 13, the second branch supply pipe 14 b, and the main heat exchanger 12. , Sent. The N 2 gas warms the stored LO 2 22 that accumulates at the bottom of the second rectifying column 20, vaporizes the O 2 gas, and retains it in the upper portion, thereby making the stored LO 2 22 ultrapure. On the other hand, the liquid itself is liquefied by the cold heat of the stored LO 2 22, and is sent to the second evaporator 24 through the second introduction pipe 23. The second evaporator 24 inside the inflated fed been LN expanded through 2 and a second inlet pipe 23 fed by in LN 2 O 2 gas below the boiling point via the second branch injection pipe 9b Cooled to temperature. On the other hand, a part of the O 2 gas in the upper space of the second rectification column 20 is sent to the second condenser 26 in the second evaporator 24 through the third reflux liquid pipe 25a. By the cooling, the O 2 gas sent into the second condenser 26 is liquefied to become a reflux liquid, and flows down from the fourth reflux liquid pipe 25 b to the upper portion of the second rectifying column 20. Reference numeral 23 a denotes a flow rate adjusting valve that adjusts the flow rate of LN 2 passing through the second introduction pipe 23.
[0016]
27 is an O 2 gas take-out pipe, and O 2 gas staying in the upper space of the second rectifying column 20 (impurities include N 2 : 180 ppm, Ar: 8863 ppm, CO: 0.86 ppm, etc.) Is sent to the main heat exchanger 12 to exchange heat with N 2 gas (from the compressor 10) passing therethrough, and the O 2 gas is heated to room temperature and released to the outside. 27a is a flow regulating valve provided on the main heat exchanger 12 downstream portion of the O 2 gas takeout pipe 27, the O 2 gas flow rate detection result of the flow meter O 2 gas takeout pipe 27 by (not shown) Based on this, the flow rate of the O 2 gas is adjusted. 28 is a product LO 2 take-out pipe, which takes out the ultra-high purity storage LO 2 22 at the bottom of the second rectifying column 20 as the product LO 2 and introduces it into the product tank 29. 28a is a liquid level control valve provided in the product LO 2 take-out pipe 28, and based on the detection result of the liquid level of the stored LO 2 22 at the bottom of the second rectifying column 20 by a liquid level gauge (not shown), The flow rate of the storage LO 2 22 passing through the product LO 2 take-out pipe 28 is adjusted, and the liquid level of the storage LO 2 22 is kept constant.
[0017]
Reference numeral 33 denotes a first N 2 gas extraction pipe extending from the upper part of the first evaporator 4, and N 2 gas accumulated in the upper space of the first evaporator 4 (LN 2 fed into the first evaporator 4 is converted into the first condenser. 5 in being vaporized in O 2 gas through the ones collected in the upper space) the feed to the main heat exchanger 12, passes through here (from the compressor 10) N 2 gas and is heat exchanged N 2 gas at normal temperature The temperature is raised to the first buffer tank 30 via the take-out pipe 35. 33a is a pressure regulating valve provided in the downstream portion of the main heat exchanger 12 of the first N 2 gas extraction pipe 33, and based on the detection result of the internal pressure in the upper space of the first evaporator 4 by a pressure gauge (not shown), The flow rate of N 2 gas passing through the first N 2 gas extraction pipe 33 is adjusted, and the internal pressure is kept constant. Reference numeral 34 denotes a second N 2 gas extraction pipe extending from the upper part of the second evaporator 24. N 2 gas accumulated in the upper space of the second evaporator 24 (LN 2 fed into the second evaporator 24 is converted into the second condenser 24). is vaporized in O 2 gas that collected in the upper space) the feed to the main heat exchanger 12 through 26, through here (from the compressor 10) N 2 gas and is heat exchanged N 2 gas at normal temperature The temperature is raised to the first buffer tank 30 via the take-out pipe 35. 34a is a pressure control valve provided in the downstream part of the main heat exchanger 12 of the second N 2 gas extraction pipe 34, based on the detection result of the internal pressure of the upper space of the second evaporator 24 by a pressure gauge (not shown), The flow rate of N 2 gas passing through the second N 2 gas extraction pipe 34 is adjusted, and the internal pressure is kept constant.
[0018]
Reference numeral 36 denotes a supply pipe for supplying N 2 gas to the first buffer tank 30. A communication pipe 37 communicates the first buffer tank 30 with the second buffer tank 31. The first buffer tank 30 is provided in the supply pipe 36, and the second buffer tank 31 is provided in the supply pipe 13. The first buffer tank 30 acts to buffer by merging the N 2 gas through the N 2 gas and supply pipe 36 sent through the takeout pipe 35. The second buffer tank 31 acts to buffer by merging the N 2 gas through the N 2 gas and feed pipe 13 sent through the communication pipe 37. Reference numeral 36 a denotes a pressure control valve provided in the refill pipe 36, which acts to keep the pressure constant based on the detection result of the pressure in the first buffer tank 30. 37a is a pressure control valve provided in the communication pipe 37, and acts to keep the pressure constant based on the detection result of the pressure in the second buffer tank 31. Reference numeral 40 denotes a vacuum pearlite heat insulating box, in which the raw material tank 1, both rectification towers 2, 20, both condensation evaporators 4, 24, the main heat exchanger 12 and the product tank 29 are accommodated. The inside of the vacuum pearlite heat insulation box 40 is kept in a vacuum state and is filled with pearlite (not shown).
[0019]
Using this apparatus, for example, LO 2 can be purified to ultrapure LO 2 as follows. That is, first, the raw material LO 2 is introduced from the raw material tank 1 through the supply pipe 7 into the lower portion of the first rectifying column 2, and high boiling components such as O 2 and CH 4 are mainly contained in the first rectifying column 2. Accumulate liquid at the bottom. The introduction amount of the raw material LO 2 is automatically controlled by the liquid level control valve 7 a, whereby the liquid level of the stored LO 2 6 that accumulates at the bottom of the first fractionator 2 is kept constant. Next, a certain amount of N 2 gas pressurized by the compressor 10 is sent to the first heater 3 at the bottom of the first rectifying column 2 through the aftercooler 11 and the main heat exchanger 12. The stored LO 2 6 at the bottom of the first rectifying column 2 is vaporized by this N 2 gas, becomes O 2 gas, rises with low-boiling components such as N 2 , Ar, CO, etc., and stays in the upper part. Further, high boiling point components such as CH 4 remain in the stored LO 2 6 and are concentrated. On the other hand, LN 2 liquefied in the first heater 3 is led out to the first introduction pipe 9, and a part thereof is sent into the first evaporator 4 through the first branch introduction pipe 9a. Used for refrigeration. Next, a part of the O 2 gas staying in the upper part of the first rectifying column 2 is sent to the first condenser 5 through the first reflux liquid pipe 8a, where it is liquefied by the above-mentioned cooling and is used as the reflux liquid. Return to rectification tower 2. Then, the reflux liquid is flowing down first fractionator 2, and fractionated by O 2 gas and the countercurrent contact to rise, to liquefy the high-boiling components CH 4, etc. of the O 2 gas, O 2 A gas or a low boiling point component such as N 2 , Ar, or CO is retained as a gas in the upper portion. In this way, the O 2 gas from which the high-boiling components such as CH 4 are substantially completely removed is taken out from the outlet pipe 19 and sent to the second rectifying column 20, while the stored LO that accumulates at the bottom of the first rectifying column 2. about 4% of 2 6 discharged by LO 2 discharge pipe 15.
[0020]
In the second fractionator 20, of the O 2 gas were fed, N 2, Ar, raising the low-boiling components such as CO is retained in the upper, liquefying the O 2 gas or the like which is a high boiling point component Lower and collect at the bottom of the second fractionator 20. Next, a certain amount of N 2 gas pressurized by the compressor 10 is sent to the second heater 21 at the bottom of the second fractionator 20 through the aftercooler 11 and the main heat exchanger 12. By this N 2 gas vaporizing reservoir LO 2 22 of the second fractionator 20 bottoms, N 2, Ar, low-boiling components such as CO is Ru are substantially completely removed.
[0021]
On the other hand, LN 2 liquefied in the second heater 21 is sent into the second evaporator 24 through the second introduction pipe 23 and used for cooling the second condenser 26. Further, LN 2 liquefied in the first heater 3 is sent into the second evaporator 24 through the second branch introduction pipe 9b and used for cooling the second condenser 26. Then, the O 2 gas staying in the upper part of the second rectifying column 20 is sent to the second condenser 26 through the third reflux liquid pipe 25a, where it is liquefied by the above-mentioned cooling and is liquefied as the reflux liquid. Return to. Then, the reflux liquid is caused to flow down in the second rectifying column 20 and brought into countercurrent contact with the rising O 2 gas to perform rectification, to liquefy the O 2 gas, and low boiling point components such as N 2 , Ar, and CO. Is retained and concentrated at the top as a gas. The main factor determining the concentration amount is the ratio of O 2 gas discharged from a source LO 2 and O 2 gas extraction pipe 27 from the second fractionator 20 top, in this embodiment, about the raw materials LO 2 11% is discharged .
[0022]
Ultra high purity was obtained as this (the impurity concentration of the order of ppb) storage LO 2 22, so as to control the liquid level constant, automatically from the product LO 2 takeout pipe 28 as a product Take out .
[0023]
On the other hand, through a low-temperature N 2 gas discharged from the first and second evaporators 4,24 to main heat exchanger 12, the passes (from the compressor 10) N 2 gas and by heat exchange N 2 gas here It cools to near liquefaction temperature, heats itself to near normal temperature, sends it to the compressor 10, pressurizes with this compressor 10, and sends it to the main heat exchanger 12 again. Thus, N 2 gas forms a circulation cycle .
[0024]
As described above, in this embodiment, Ru can be impurity concentration obtain ultrapure LO 2 order of ppb.
[0025]
Moreover, since the production amount of ultra-high purity LO 2 is determined only by the flow rate of O 2 gas supplied from the first rectification column 2 to the second rectification column 20, it is difficult to measure the flow rate of LO 2 and the like. Conventional liquid flow measurement is not required, operation is greatly simplified, and reliability is improved .
[0026]
FIG. 2 shows a configuration diagram of another embodiment of the liquid oxygen purifying apparatus of the present invention. In this embodiment, the first evaporator 4 in the embodiment shown in FIG. For this reason, in this embodiment, the first evaporator 4, the first introduction pipe 9, the first branch introduction pipe 9a, the second branch introduction pipe 9b, and the first N 2 gas extraction pipe 33 are eliminated, and the second evaporator 24 is removed. The 1st condenser 5 is arrange | positioned in the inside. In addition, an introduction pipe 50 and a flow rate adjusting valve 50a for connecting the first and second condensers 5 and 26 to the second evaporator 24 are provided. Other parts are the same as those of the embodiment shown in FIG. 1, and the same reference numerals are given to the same parts. Also in this embodiment, there are the same operations and effects as the embodiment shown in FIG.
[0027]
【The invention's effect】
As described above, according to the liquid oxygen purification method of the present invention, oxygen in the raw material liquid oxygen and components having lower boiling points than oxygen are taken out in a gaseous state in the first rectifying column and used as a raw material for the second rectifying column. In the liquid obtained in the second rectification column, the component having a lower boiling point than oxygen is rarely liquefied and mixed. Therefore, the liquid obtained in the second rectification column becomes ultrahigh-purity liquid oxygen having an impurity concentration of ppb order. On the other hand, according to the apparatus of the present invention, the above method can be easily realized, and liquid oxygen can be purified efficiently.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a liquid oxygen purifying apparatus showing an embodiment of the present invention.
FIG. 2 is a configuration diagram of a liquid oxygen purifying apparatus showing another embodiment of the present invention.
[Explanation of symbols]
2 First rectification tower 20 Second rectification tower
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00510598A JP3999865B2 (en) | 1998-01-13 | 1998-01-13 | Liquid oxygen purification method and apparatus used therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00510598A JP3999865B2 (en) | 1998-01-13 | 1998-01-13 | Liquid oxygen purification method and apparatus used therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11201635A JPH11201635A (en) | 1999-07-30 |
| JP3999865B2 true JP3999865B2 (en) | 2007-10-31 |
Family
ID=11602094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00510598A Expired - Fee Related JP3999865B2 (en) | 1998-01-13 | 1998-01-13 | Liquid oxygen purification method and apparatus used therefor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3999865B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6912872B2 (en) * | 2002-08-23 | 2005-07-05 | The Boc Group, Inc. | Method and apparatus for producing a purified liquid |
| JP6734621B2 (en) * | 2014-02-20 | 2020-08-05 | オルガノ株式会社 | Ozone water supply method and ozone water supply device |
-
1998
- 1998-01-13 JP JP00510598A patent/JP3999865B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11201635A (en) | 1999-07-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0719727A (en) | Separation of air | |
| US4805412A (en) | Krypton separation | |
| JP2001509246A (en) | High pressure nitrogen production method and apparatus | |
| EP0798524B1 (en) | Ultra high purity nitrogen and oxygen generator unit | |
| US9546815B2 (en) | Method and device for separating a gas mixture by cryogenic distillation | |
| US5743112A (en) | Ultra high purity nitrogen and oxygen generator unit | |
| JP3999865B2 (en) | Liquid oxygen purification method and apparatus used therefor | |
| JPH10132458A (en) | Method and equipment for producing oxygen gas | |
| JP5005894B2 (en) | Nitrogen generation method and apparatus used therefor | |
| US6050106A (en) | Ultra high purity nitrogen and oxygen generator unit | |
| JPH0842962A (en) | Method and equipment for separating air at low temperature | |
| JPH0217795B2 (en) | ||
| US4530708A (en) | Air separation method and apparatus therefor | |
| JP3644918B2 (en) | Air separation device and air separation method | |
| JP3667875B2 (en) | Air liquefaction separation method | |
| JP3884240B2 (en) | Air separation device and control operation method thereof | |
| JP3976188B2 (en) | Product gas production method using air separation device | |
| JP4960277B2 (en) | Method for producing ultra-high purity oxygen | |
| JPH09217982A (en) | Method for liquefying and separating air and apparatus therefor | |
| JP2008057804A (en) | Manufacturing method of refined argon | |
| JPH07218121A (en) | Method and apparatus for manufacturing high purity nitrogen gas | |
| JP3181482B2 (en) | High-purity nitrogen gas production method and apparatus used therefor | |
| JP2000180051A (en) | Manufacture of ultrahigh purity nitrogen | |
| JP3306668B2 (en) | Air liquefaction separation method and apparatus | |
| JP3513667B2 (en) | Air liquefaction separation method and apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20040323 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20040524 |
|
| A911 | Transfer of reconsideration by examiner before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A911 Effective date: 20040713 |
|
| A912 | Removal of reconsideration by examiner before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A912 Effective date: 20040820 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070810 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100817 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110817 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110817 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120817 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120817 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130817 Year of fee payment: 6 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |