JPH0668435B2 - Air liquefaction separation method - Google Patents

Air liquefaction separation method

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Publication number
JPH0668435B2
JPH0668435B2 JP61036102A JP3610286A JPH0668435B2 JP H0668435 B2 JPH0668435 B2 JP H0668435B2 JP 61036102 A JP61036102 A JP 61036102A JP 3610286 A JP3610286 A JP 3610286A JP H0668435 B2 JPH0668435 B2 JP H0668435B2
Authority
JP
Japan
Prior art keywords
rectification column
sub
gas
air
pipe
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
Application number
JP61036102A
Other languages
Japanese (ja)
Other versions
JPS62194178A (en
Inventor
秀幸 本田
Original Assignee
日本酸素株式会社
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Filing date
Publication date
Application filed by 日本酸素株式会社 filed Critical 日本酸素株式会社
Priority to JP61036102A priority Critical patent/JPH0668435B2/en
Publication of JPS62194178A publication Critical patent/JPS62194178A/en
Publication of JPH0668435B2 publication Critical patent/JPH0668435B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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
    • F25J3/04436—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 at least a triple pressure main column system
    • F25J3/04448—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 at least a triple pressure main column system in a double column flowsheet with an intermediate pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04309—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/24—Processes or apparatus using other separation and/or other processing means using regenerators, cold accumulators or reversible heat exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/30—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
    • F25J2240/42—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval the fluid being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
    • F25J2240/44—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval the fluid being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/40—Processes or apparatus involving steps for recycling of process streams the recycled stream being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、酸素及び窒素を同時に採取する空気液化分離
方法に関する。Description: TECHNICAL FIELD The present invention relates to an air liquefaction separation method for simultaneously collecting oxygen and nitrogen.

〔従来の技術〕[Conventional technology]

酸素，窒素を同時に採取する従来の空気液化分離方法と
しては、例えば第３図及び第４図に示す方法がある。As a conventional air liquefaction separation method for simultaneously collecting oxygen and nitrogen, there is a method shown in FIGS. 3 and 4, for example.

第３図及び第４図に示す方法は、空気圧縮機１と、リバ
ーシング熱交換器２と、上部塔3aと下部塔3bとの間に凝
縮器3cを介在させ、かつ上部塔3aの上部に高純窒素精留
塔3dを設けた複精留塔３と、膨張タービン４とを備えて
なる空気分離装置における空気液化分離方法を示すもの
である。In the method shown in FIGS. 3 and 4, the air compressor 1, the reversing heat exchanger 2, the condenser 3c between the upper tower 3a and the lower tower 3b, and the upper part of the upper tower 3a are used. 2 shows an air liquefaction separation method in an air separation device including a double rectification column 3 in which a high-purity nitrogen rectification column 3d is provided and an expansion turbine 4.

まず、第３図に示す方法を説明すると、空気圧縮機１で
圧縮された原料空気は、管５からリバーシング熱交換器
２に導入され、ここで冷却されて水，炭酸ガスが除去さ
れ、管6,7を通って下部塔3bの下部に導入され、ここで
空気の予備精留が行なわれる。First, explaining the method shown in FIG. 3, the raw material air compressed by the air compressor 1 is introduced from the pipe 5 to the reversing heat exchanger 2, where it is cooled to remove water and carbon dioxide gas, It is introduced into the lower part of the lower tower 3b through the pipes 6 and 7, where the pre-rectification of air is carried out.

そして、下部塔3b頂部から高純液化窒素が抜出され管８
により高純窒素精留塔3d上部に導入され、また、下部塔
3bの中間部及び底部から不純液体窒素及び液体空気が抜
出され、管9,10より、夫々上部塔3aの中間部及び上部に
導入され、ここで精留が行なわれる。Then, high-purity liquefied nitrogen was extracted from the top of the lower tower 3b and the pipe 8
Introduced into the upper part of the high-purity nitrogen rectification column 3d,
Impure liquid nitrogen and liquid air are extracted from the middle part and the bottom part of 3b and introduced into the middle part and the upper part of the upper tower 3a through pipes 9 and 10, respectively, where rectification is carried out.

上部塔3aの頂部からは管11により不純窒素ガス（廃窒素
ガス）が抜出され、リバーシング熱交換器２を通して大
気に放出される。上部塔3aの底部からは管12により酸素
ガスが抜出され、リバーシング熱交換器２を通して常温
にされ製品酸素ガスとして取出される。また、高純窒素
精留塔3dの頂部からは管13により高純窒素ガスが抜出さ
れ、リバーシング熱交換器２を通して常温にされ、製品
窒素ガスとして取出される。Impurity nitrogen gas (waste nitrogen gas) is extracted from the top of the upper tower 3a through a pipe 11 and is discharged to the atmosphere through the reversing heat exchanger 2. Oxygen gas is taken out from the bottom of the upper tower 3a through a pipe 12, and is brought to room temperature through the reversing heat exchanger 2 to be taken out as product oxygen gas. Further, from the top of the high-purity nitrogen rectification column 3d, high-purity nitrogen gas is extracted through a pipe 13, is brought to room temperature through the reversing heat exchanger 2, and is taken out as product nitrogen gas.

そして、装置の寒冷バランスをとるため、管６から管14
により空気の一部が抜出され、リバーシング熱交換器２
で再熱された後、管15より膨張タービン４に導入され、
寒冷を発生させ、膨張した空気は管16より上部塔3aの中
間部に導入されている。And to balance the cold of the device, pipe 6 to pipe 14
Part of the air is extracted by the reversing heat exchanger 2
After being reheated in, it is introduced into the expansion turbine 4 from the pipe 15,
The air that has generated cold and is expanded is introduced into the middle part of the upper tower 3a through the pipe 16.

次に第４図に示す方法は、前記第３図に示す装置の寒冷
バランスのとり方を変更したもので、下部塔3bの中間部
より管17により不純窒素ガスを抜出し、これをリバーシ
ング熱交換器２で再熱した後、管18により膨張タービン
４に導入し、膨張した空気を管19より管11の廃窒素ガス
中に逃がすようにしたものである。Next, the method shown in FIG. 4 is a modification of the cold balance of the apparatus shown in FIG. 3, in which impure nitrogen gas is extracted from the middle part of the lower tower 3b through a pipe 17 and is used for reversing heat exchange. After reheated in the vessel 2, it is introduced into the expansion turbine 4 through the pipe 18 and the expanded air is allowed to escape from the pipe 19 into the waste nitrogen gas in the pipe 11.

〔発明が解決しようとする問題点〕[Problems to be solved by the invention]

ところで、このような従来の空気液化分離方法では、上
部塔3aの上に高純窒素精留塔3dを設けており、この高純
窒素精留塔3dは、精留段毎の差圧により圧力が多少低く
なるが、基本的には上部塔3aの運転圧力と等しい圧力で
運転していた。By the way, in such a conventional air liquefaction separation method, a high-purity nitrogen rectification column 3d is provided on the upper column 3a, and the high-purity nitrogen rectification column 3d is pressured by the differential pressure of each rectification stage. Was slightly lower, but basically the pressure was equal to the operating pressure of the upper tower 3a.

ところが、装置設計上、製品窒素ガス出口圧力を大気圧
以上の圧力に保つためには、製品窒素ガス圧力＋装置内
流動圧損＋高純窒素精留塔3d及び上部塔3a圧損によって
定まる上部塔3aの底部圧力が、一般に廃窒素ガスや製品
酸素ガスの装置内流動圧損等によって要求される上部塔
3a底部圧力より高くなり、この結果、空気圧縮機１吐出
圧力を上昇させる必要があるため、製品原単位が悪くな
る欠点があった。However, in the equipment design, in order to maintain the product nitrogen gas outlet pressure at a pressure higher than atmospheric pressure, the product nitrogen gas pressure + in-apparatus flow pressure loss + high-purity nitrogen rectification column 3d and upper column 3a The bottom pressure of the upper column is generally required due to the pressure loss of waste nitrogen gas and product oxygen gas flowing inside the equipment.
3a It becomes higher than the bottom pressure, and as a result, it is necessary to increase the discharge pressure of the air compressor 1, so that there is a drawback that the product unit consumption becomes worse.

すなわち、前記第３図及び第４図に示す従来方法では、
一般に、製品窒素ガス出口圧力を300mmAqとし、高純窒
素精留塔3d頂部出口より装置出口までの流動圧損を1800
mmAq、高純窒素精留塔3dと上部塔3aの圧損を2600mmAq程
度必要とすることから、上部塔3a底部の圧力は0.47Kg／
cm2Gの圧力が必要となり、凝縮器3cで上部塔3a底部に溜
る液化酸素を蒸発させるために必要な下部塔3bの頂部圧
力は4.75Kg／cm2Gとなり、空気系統の圧力損失を加えた
空気圧縮機１吐出圧力は5.0Kg／cm2Gとなる。That is, in the conventional method shown in FIG. 3 and FIG.
Generally, the product nitrogen gas outlet pressure is 300 mmAq, and the flow pressure loss from the high pure nitrogen rectification column 3d top outlet to the equipment outlet is 1800.
mmAq, pressure loss of high-purity nitrogen rectification column 3d and upper column 3a is required to be about 2600 mmAq. Therefore, the pressure at the bottom of upper column 3a is 0.47 Kg /
Since a pressure of cm 2 G is required, the top pressure of the lower tower 3b required to evaporate the liquefied oxygen accumulated at the bottom of the upper tower 3a in the condenser 3c is 4.75 Kg / cm 2 G, and the pressure loss of the air system is added. The discharge pressure of the air compressor 1 is 5.0 kg / cm 2 G.

一方、廃窒素ガス系統を基準とした場合の上部塔3a底部
圧力は、同様にして求めると、0.40Kg／cm2Gで充分であ
り、空気圧縮機１吐出圧力は、4.80Kg／cm2Gとなり、前
記5.0Kg／cm2Gとの差は、製品酸素ガス10000Nm3／ｈの
装置で年間電力費で約１千万円の差を生ずる。On the other hand, the bottom pressure of the upper tower 3a based on the waste nitrogen gas system is 0.40 Kg / cm 2 G when calculated similarly, and the discharge pressure of the air compressor 1 is 4.80 Kg / cm 2 G. Therefore, the difference from the above-mentioned 5.0 kg / cm 2 G is about 10 million yen in the annual electric power cost in a device with a product oxygen gas of 10,000 Nm 3 / h.

本発明は上記の点に鑑み、上部塔底部圧力を従来のよう
な製品窒素ガス系統で決定する必要をなくし、廃窒素ガ
ス又は酸素ガス系統（一般には廃窒素ガス系統）によっ
て決定するようにし、上部塔底部圧力及び空気圧縮機吐
出圧力を低下させて、製品原単位を良くした空気液化分
離方法を提供することを目的とする。In view of the above points, the present invention eliminates the need to determine the upper column bottom pressure in the conventional product nitrogen gas system, and determines the waste nitrogen gas or oxygen gas system (generally waste nitrogen gas system). An object of the present invention is to provide an air liquefaction separation method in which the product basic unit is improved by lowering the pressure at the bottom of the upper tower and the discharge pressure of the air compressor.

〔問題点を解決するための手段〕[Means for solving problems]

上記目的を達成するため、本発明方法は、従来の高純窒
素精留塔を上部塔より離して副精留塔とし、これを基本
的には上部塔上部圧力より高い圧力で運転し、膨張ター
ビン（タービンバイパスも含む）で処理された低圧ガス
を副精留塔下部に導入して副精留塔の上昇ガスとし、副
精留塔下部に溜る液を還流液として、その組成に応じて
上部塔の適当な位置に供給するようにしたことを特徴と
している。In order to achieve the above object, the method of the present invention, the conventional high-purity nitrogen rectification column is separated from the upper column to form a sub-rectification column, which is basically operated at a pressure higher than the upper column upper pressure and expanded. The low-pressure gas processed by the turbine (including turbine bypass) is introduced into the lower part of the sub-rectification column as the rising gas of the sub-rectification column, and the liquid accumulated in the lower part of the sub-rectification column is used as the reflux liquid, depending on its composition. The feature is that it is supplied to an appropriate position in the upper tower.

〔実施例〕〔Example〕

以下、本発明の実施例を第１図及び第２図に基づいて説
明する。尚、第３図及び第４図に示す従来例と同一要素
のものには同一符号を付して説明する。An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same elements as those of the conventional example shown in FIGS. 3 and 4 are designated by the same reference numerals for description.

第１図は本発明の第１実施例を示すもので、空気圧縮機
１で4.8Kg／cm2Gに圧縮された41500Nm3／ｈの原料空気
は、管５よりリバーシング熱交換器２に導入され、ここ
で冷却されて原料空気中の水，炭酸ガスが除去され、管
6,7を通って上部塔3a,凝縮器3c及び下部塔3bより構成さ
れる複精留塔３の下部塔3bの下部に導入される。FIG. 1 shows a first embodiment of the present invention, in which 41500 Nm 3 / h of raw material air compressed to 4.8 kg / cm 2 G by the air compressor 1 is supplied to the reversing heat exchanger 2 through the pipe 5. Introduced, cooled here to remove water and carbon dioxide in the raw material air,
It is introduced into the lower part of the lower column 3b of the double rectification column 3 composed of the upper column 3a, the condenser 3c and the lower column 3b through 6,7.

下部塔3bでは、空気の予備精留が行なわれ、下部塔3bの
頂部から高純液化窒素が管８により抜出され、弁20を介
して副精留塔21の上部に還流液として供給される。ま
た、下部塔3b中間部及び底部から不純液体窒素及び液体
空気が管9,10を通して抜出され、夫々上部塔3aの上部及
び中間部に弁22,23を介して還流液として導入される。In the lower tower 3b, preliminary rectification of air is carried out, and highly pure liquefied nitrogen is extracted from the top of the lower tower 3b by a pipe 8 and supplied as a reflux liquid to the upper portion of the sub-rectification tower 21 via a valve 20. It Further, impure liquid nitrogen and liquid air are withdrawn from the middle and bottom of the lower tower 3b through pipes 9 and 10, respectively, and introduced as reflux into the upper and middle parts of the upper tower 3a via valves 22 and 23, respectively.

上部塔3aでは導入された還流液が流下し、凝縮器3cにお
いて0.40Kg／cm2Gの液体酸素の気化と、一方下部塔3bか
らの4.75Kg／cm2Gの上昇窒素ガスの凝縮が行なわれる。The introduced reflux liquid flows down in the upper tower 3a, vaporizing 0.40 Kg / cm 2 G of liquid oxygen in the condenser 3c, and condensing the rising nitrogen gas of 4.75 Kg / cm 2 G from the lower tower 3b. Be done.

そして、上部塔3aの頂部より管11にて不純窒素ガス（廃
窒素ガス）が抜出され、リバーシング熱交換器２を通し
て大気に放出される。また、上部塔3aの底部より管12に
て製品酸素ガスが抜出され、リバーシング熱交換器２を
通して常温にされ、取出される。Then, impure nitrogen gas (waste nitrogen gas) is extracted from the top of the upper tower 3a through the pipe 11, and is discharged to the atmosphere through the reversing heat exchanger 2. Further, the product oxygen gas is taken out from the bottom of the upper tower 3a through the pipe 12, is brought to room temperature through the reversing heat exchanger 2, and is taken out.

一方、装置の寒冷バランスを保つため、管14により管６
を通る空気の一部が分岐され、リバーシング熱交換器２
で再熱された後、管15より膨張タービン４に入り寒冷を
発生させる。膨張した空気は管16により副精留塔21に導
入され、上昇ガスとなり、前記管８により導入された還
流高純液化窒素との精留作用により、高純窒素ガスとな
って副精留塔21頂部の管13より抜出され、リバーシング
熱交換器２を通して常温にされ、取出される。On the other hand, in order to maintain the cold balance of the device, the pipe 14
A part of the air passing through is branched and the reversing heat exchanger 2
After being reheated in, the pipe 15 enters the expansion turbine 4 to generate cold. The expanded air is introduced into the sub-rectification column 21 through the pipe 16 and becomes ascending gas, and by the rectification action with the reflux highly pure liquefied nitrogen introduced through the pipe 8, it becomes high-purity nitrogen gas and becomes the sub-rectification column. 21 It is taken out from the pipe 13 at the top, passed through the reversing heat exchanger 2 to room temperature, and taken out.

尚、この高純窒素ガスは従来300mmAqで送出されていた
が、本実施例では副精留塔21は下部で約0.35Kg／cm2Gで
運転され、送出高純窒素ガス圧力800mmAqとすることが
できる。また、膨張タービン４での必要量が副精留塔21
の所要量に満たない場合は管14から分岐した管24により
空気を加給し、逆に過剰の場合は管16から分岐した破線
で示す管25により、上部塔3aの適切な段に過剰量を振り
分けるようにするとよい。Incidentally, this high-purity nitrogen gas was conventionally delivered at 300 mmAq, but in this embodiment, the sub-rectification column 21 is operated at about 0.35 kg / cm 2 G in the lower part, and the delivery high-purity nitrogen gas pressure is 800 mmAq. You can In addition, the required amount in the expansion turbine 4 is 21
If it is less than the required amount of the above, air is supplied by a pipe 24 branched from the pipe 14, and conversely, if it is excessive, an excess amount is supplied to an appropriate stage of the upper tower 3a by a pipe 25 shown by a broken line branched from the pipe 16. You should sort them.

副精留塔21の底部に溜る液体空気は管26により抜出さ
れ、上部塔3aの組成に見合った段（約0.25Kg／cm2G）へ
導入される。The liquid air accumulated at the bottom of the sub-rectification column 21 is extracted by a pipe 26 and introduced into a stage (about 0.25 kg / cm 2 G) corresponding to the composition of the upper column 3a.

次に第２図は本発明の第２実施例を示し、寒冷発生源で
ある膨張タービン44の処理流体として、上述の第１実施
例の如く管６から分岐した空気を用いることなく、下部
塔3bの中間部から管17により抜出した不純窒素ガスを用
いたもので、この管17により抜出した不純窒素ガスを、
リバーシング熱交換器２で再熱した後、管18により膨張
タービン４に導入し、膨張した空気を管19より副精留塔
21の下部に導入して上昇ガスとしたものである。Next, FIG. 2 shows a second embodiment of the present invention, which does not use the air branched from the pipe 6 as the treatment fluid of the expansion turbine 44 which is the cold generation source, as in the above-mentioned first embodiment. Impurity nitrogen gas extracted from the middle part of 3b by a pipe 17 is used, and the impurity nitrogen gas extracted by this pipe 17 is
After reheated by the reversing heat exchanger 2, it is introduced into the expansion turbine 4 through the pipe 18, and the expanded air is supplied through the pipe 19 to the sub-rectification column.
It was introduced into the lower part of 21 and used as rising gas.

そしてこのとき、膨張タービン４での必要量が副精留塔
21の所要量に満たない場合は、管17から分岐した管24に
より不純窒素ガスを加給し、逆に膨張タービン４からの
処理流体量が多い場合は、管19からの窒素ガスを破線で
示す管27を通して管11の廃ガス中に逃がし、また副精留
塔21の底部に溜った不純液体窒素は管26により上部塔3a
の所望位置へ導入するようにしている。And at this time, the required amount in the expansion turbine 4 is the sub-rectification column.
When the required amount of 21 is not satisfied, impure nitrogen gas is added by the pipe 24 branched from the pipe 17, and conversely, when the amount of treated fluid from the expansion turbine 4 is large, the nitrogen gas from the pipe 19 is indicated by a broken line. Impurity liquid nitrogen released through the pipe 27 into the waste gas of the pipe 11 and accumulated at the bottom of the sub-rectification column 21 is fed by the pipe 26 to the upper column 3a.
It is designed to be introduced at the desired position.

尚、以上の実施例では、リバーシング熱交換器２を使用
した場合について述べたが、それに代えて吸着器を使用
してもよい。また、膨張タービン４の出口温度が高い場
合は副精留塔21の下部または凝縮器3cの液体酸素中にリ
ボイラーを設け、該リボイラーを通して温度を下げた
後、副精留塔21に導入すれば、副精留塔21を安定に運転
することができる。さらに、下部塔3bの上部から管８で
供給される高純液化窒素が副精留塔21の還流液量として
過剰な場合（既設装置に副精留塔21を設けた場合など）
は、高純液化窒素の一部を管９の不純液化窒素に混入し
て上部塔3aへ供給するようにしてもよい。In the above embodiments, the case where the reversing heat exchanger 2 is used has been described, but an adsorber may be used instead. If the outlet temperature of the expansion turbine 4 is high, a reboiler is provided in the lower part of the sub-rectification column 21 or in the liquid oxygen of the condenser 3c, and the temperature is lowered through the reboiler before being introduced into the sub-rectification column 21. The sub-rectification column 21 can be operated stably. Further, when the highly pure liquefied nitrogen supplied from the upper part of the lower column 3b through the pipe 8 is excessive as the reflux liquid amount of the sub-rectification column 21 (when the sub-rectification column 21 is provided in the existing device, etc.)
May be mixed with part of the highly pure liquefied nitrogen in the impure liquefied nitrogen in the pipe 9 and supplied to the upper column 3a.

本実施例は以上のように構成したので、原料空気圧力を
従来方法に比べ約0.2Kg／cm2G低下でき、従ってこの分
電力消費量を削減できる。また、製品窒素送出圧力を従
来の300mmAq以上に上昇でき窒素ガス送出圧縮機を小さ
くできるとともに、消費動力を削減できる。さらに、既
設装置に副精留塔21を追加すれば、既設空気圧縮機の吐
出圧を変えずに運転することも可能となる。Since the present embodiment is configured as described above, the raw material air pressure can be reduced by about 0.2 Kg / cm 2 G as compared with the conventional method, and therefore the power consumption can be reduced accordingly. In addition, the product nitrogen delivery pressure can be raised above the conventional 300 mmAq, and the nitrogen gas delivery compressor can be made smaller and the power consumption can be reduced. Furthermore, if the sub-rectification column 21 is added to the existing device, it is possible to operate without changing the discharge pressure of the existing air compressor.

〔発明の効果〕〔The invention's effect〕

本発明の空気液化分離方法は、以上のように複精留塔の
下部塔上部より高純液化窒素を抜出して、副精留塔上部
に還流液として導入し、膨張タービンからの処理ガスの
全部又は一部を前記副精留塔へ導入して上昇ガスとし、
該副精留塔頂部より高純窒素ガスを抜出すとともに、副
精留塔下部に溜る液をその組成に応じて上部塔の適切な
段に還流液として導入せしめるようにしたから、副精留
塔の操作圧を上部塔と無関係に設定することができ、上
部塔は通常装置の高純窒素精留段分（前記副精留塔該当
分）だけ低い圧力で運転でき、上部塔底部圧力を従来の
ような製品窒素ガス系統で決定する必要がなく、廃窒素
ガス又は酸素ガス系統によって決定すればよく、その結
果、上部塔底部圧力、空気圧縮機吐出圧力を低下させる
ことができ、製品原単位が良くなる。The air liquefaction separation method of the present invention, as described above, extracts highly pure liquefied nitrogen from the upper part of the lower part of the double rectification column and introduces it as a reflux liquid into the upper part of the secondary rectification column, and all of the processed gas from the expansion turbine is extracted. Alternatively, a part of the gas is introduced into the sub-rectification column to generate rising gas,
High-purity nitrogen gas was extracted from the top of the sub-rectification column, and the liquid accumulated in the lower part of the sub-rectification column was introduced as a reflux liquid into an appropriate stage of the upper column according to its composition. The operating pressure of the column can be set independently of the upper column, and the upper column can be operated at a lower pressure by the high pure nitrogen rectification stage of the equipment (corresponding to the sub-rectification column), and the upper column bottom pressure It is not necessary to determine with the conventional product nitrogen gas system, but it may be determined with the waste nitrogen gas or oxygen gas system, and as a result, the pressure at the bottom of the upper tower and the discharge pressure of the air compressor can be reduced, and The unit improves.

【図面の簡単な説明】[Brief description of drawings]

第１図は本発明方法の第１実施例を示す系統図、第２図
は第２実施例を示す系統図、第３図及び第４図は従来の
空気液化分離方法の系統図である。 １……空気圧縮機、２……リバーシング熱交換器、３…
…複精留塔、3a……上部塔、3b……下部塔、3c……凝縮
器、４……膨張タービン、21……副精留塔FIG. 1 is a system diagram showing a first embodiment of the method of the present invention, FIG. 2 is a system diagram showing a second embodiment, and FIGS. 3 and 4 are system diagrams of a conventional air liquefaction separation method. 1 ... Air compressor, 2 ... Reversing heat exchanger, 3 ...
… Double rectification tower, 3a …… Upper tower, 3b …… Lower tower, 3c …… Condenser, 4 …… Expansion turbine, 21 …… Sub-rectification tower

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】原料空気を加圧，冷却し、水及び炭酸ガス
を除去して精製し、複精留塔に導入して液化精留を行な
い、酸素，窒素を採取するとともに、寒冷バランスを膨
張タービンからの処理ガスにて保つようにした空気液化
分離方法において、前記複精留塔の下部塔上部より高純
液化窒素を抜出して、副精留塔上部に還流液として導入
し、前記膨張タービンからの処理ガスの全部又は一部を
前記副精留塔へ導入して上昇ガスとし、該副精留塔頂部
より高純窒素ガスを抜出すとともに、副精留塔下部に溜
る液をその組成に応じて上部塔の適切な段に還流液とし
て導入せしめることを特徴とする空気液化分離方法。1. A raw material air is pressurized and cooled to remove water and carbon dioxide gas for purification, and then introduced into a double rectification column for liquefaction rectification to collect oxygen and nitrogen, and to maintain a cold balance. In the air liquefaction separation method so as to keep the treated gas from the expansion turbine, high-purity liquefied nitrogen is extracted from the upper part of the lower part of the double rectification column, and introduced as a reflux liquid in the upper part of the sub-rectification column, and the expansion is performed. All or a part of the treated gas from the turbine is introduced into the sub-rectification column to be an ascending gas, and high-purity nitrogen gas is extracted from the top of the sub-rectification column, and the liquid accumulated in the lower part of the sub-rectification column is An air liquefaction separation method characterized by introducing as a reflux liquid into an appropriate stage of an upper tower depending on the composition. 【請求項２】原料空気の一部又は下部塔からの不純窒素
ガスの一部を前記副精留塔に導入して上昇ガスとしたこ
とを特徴とする特許請求の範囲第１項記載の空気液化分
離方法。2. The air according to claim 1, wherein a part of the raw material air or a part of the impure nitrogen gas from the lower column is introduced into the sub-rectification column to be a rising gas. Liquefaction separation method.
JP61036102A 1986-02-20 1986-02-20 Air liquefaction separation method Expired - Fee Related JPH0668435B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61036102A JPH0668435B2 (en) 1986-02-20 1986-02-20 Air liquefaction separation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61036102A JPH0668435B2 (en) 1986-02-20 1986-02-20 Air liquefaction separation method

Publications (2)

Publication Number Publication Date
JPS62194178A JPS62194178A (en) 1987-08-26
JPH0668435B2 true JPH0668435B2 (en) 1994-08-31

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ID=12460402

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Application Number Title Priority Date Filing Date
JP61036102A Expired - Fee Related JPH0668435B2 (en) 1986-02-20 1986-02-20 Air liquefaction separation method

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Country Link
JP (1) JPH0668435B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4519010B2 (en) * 2005-06-20 2010-08-04 大陽日酸株式会社 Air separation device
US9103587B2 (en) * 2009-12-17 2015-08-11 L'Air Liquide Société Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude Process and apparatus for the separation of air by cryogenic distillation

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5413469A (en) * 1977-07-01 1979-01-31 Hitachi Ltd Controlling method for air separation plant
JPS5439397A (en) * 1977-09-05 1979-03-26 Hitachi Ltd Method of controlling coarse argon column attached to air liquefaction separator
JPS5644577A (en) * 1979-09-19 1981-04-23 Hitachi Ltd Method of sampling pressurized nitrogen for air separator

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