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JP7583417B1 - Nitrogen generator and nitrogen production method - Google Patents

Nitrogen generator and nitrogen production method Download PDF

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JP7583417B1
JP7583417B1 JP2024017348A JP2024017348A JP7583417B1 JP 7583417 B1 JP7583417 B1 JP 7583417B1 JP 2024017348 A JP2024017348 A JP 2024017348A JP 2024017348 A JP2024017348 A JP 2024017348A JP 7583417 B1 JP7583417 B1 JP 7583417B1
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nitrogen
heat exchanger
gas
main heat
rectification column
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マキシム ランシュー
献児 廣瀬
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LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—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
    • F25J3/0423—Subcooling of liquid process streams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
    • F25J3/04206—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product
    • F25J3/04212—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product and simultaneously condensing vapor from a column serving as reflux within the or another column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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    • 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
    • F25J3/04236—Integration of different exchangers in a single core, so-called integrated cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04309—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—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
    • F25J3/04321—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 oxygen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04381—Details relating to the work expansion, e.g. process parameter etc. using work extraction by mechanical coupling of compression and expansion so-called companders
    • 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
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04393—Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
    • 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
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high 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
    • 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
    • F25J2200/54—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column in the low pressure column of a double 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/42—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being nitrogen

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  • Engineering & Computer Science (AREA)
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  • Mechanical Engineering (AREA)
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Abstract

【課題】複式精留塔でのカスケードプロセスにおいて、昇圧膨張プロセスを利用して、第一精留塔から導出される製品窒素の回収率を低下させることなく、熱効率にも優れた窒素製造方法を提供する。。
【解決手段】主熱交換器１と、第一窒素精留塔２と、第一窒素凝縮器３と、第二窒素精留塔４と、第二窒素凝縮器５と、第一窒素ブースター７１、第一窒素膨張タービン７２と、冷却装置８を備える窒素発生装置を用いた窒素製造方法であって、第一窒素精留塔２から導出される第一窒素ガスの一部が、主熱交換器１に導入され、導出された第一製品窒素ガスの少なくとも一部が、第一窒素ブースター７１で昇圧され、冷却装置８で冷却された後で、主熱交換器１の温端から再導入され、主熱交換器１の中間から導出されて第一窒素膨張タービン７２で膨張して冷却されるステップを含む。
【選択図】図１

The present invention provides a nitrogen production method that utilizes a pressure boosting expansion process in a cascade process in a double rectification column, without reducing the recovery rate of the product nitrogen discharged from a first rectification column, and that also has excellent thermal efficiency.
[Solution] A nitrogen production method using a nitrogen generation apparatus equipped with a main heat exchanger 1, a first nitrogen rectification column 2, a first nitrogen condenser 3, a second nitrogen rectification column 4, a second nitrogen condenser 5, a first nitrogen booster 71, a first nitrogen expansion turbine 72, and a cooling device 8, includes the steps of introducing a portion of the first nitrogen gas discharged from the first nitrogen rectification column 2 into the main heat exchanger 1, and at least a portion of the discharged first product nitrogen gas being pressurized in the first nitrogen booster 71 and cooled in the cooling device 8, before being reintroduced from the warm end of the main heat exchanger 1, discharged from the middle of the main heat exchanger 1, and expanded and cooled in the first nitrogen expansion turbine 72.
[Selected Figure] Figure 1

Description

本発明は、窒素発生装置および窒素製造方法に関し、例えば、深冷空気分離装置の内、主に高純度の窒素ガスを大量に製造することを目的とした窒素発生装置および窒素製造方法に関する。 The present invention relates to a nitrogen generator and a nitrogen production method, for example, a nitrogen generator and a nitrogen production method intended to produce large amounts of high-purity nitrogen gas in a cryogenic air separation unit.

大気から窒素を大量に分離精製して供給する適当な方法として、深冷空気分離法が知られている。その中でも窒素を製造するための精留塔を２塔備えた複式精留システムは、精留塔が１塔の単式精留システムと比べて、窒素需要に対して塔径を小さくできることから、精留塔の輸送が容易となって建設コストを低減できるという利点がある。このため、特に大量の窒素需要があり窒素発生装置が大型化する場合は、複式精留システムの内、窒素製造原単位（ＳＰＣ， Ｓｐｅｃｉｆｉｃ Ｐｏｗｅｒ Ｃｏｎｓｕｍｐｔｉｏｎ：比消費電力）が優れたカスケードプロセス、即ち２つの窒素精留塔の各々が窒素凝縮器を頂部に備え、それぞれの窒素精留塔の頂部から製品窒素ガスを供給するプロセスが好適である。 The cryogenic air separation method is known as a suitable method for separating and purifying a large amount of nitrogen from the atmosphere and supplying it. Among them, a double rectification system equipped with two rectification towers for producing nitrogen has the advantage that the tower diameter can be made smaller relative to the nitrogen demand compared to a single rectification system with one rectification tower, making it easier to transport the rectification towers and reducing construction costs. For this reason, when there is a particularly large demand for nitrogen and the nitrogen generation equipment is large, among the double rectification systems, a cascade process with excellent nitrogen production unit consumption (SPC, Specific Power Consumption: specific power consumption) is preferable, that is, a process in which each of two nitrogen rectification towers is equipped with a nitrogen condenser at the top and product nitrogen gas is supplied from the top of each nitrogen rectification tower.

深冷空気分離プロセスを構成するためには、冷熱バランスを維持するように寒冷を供給する必要があって、そのためにはプロセスガスを供給する膨張タービンが適用される。適用されるプロセスガスとしては、原料空気の一部（例えば、特許文献１、２参照）、廃ガスとして系外へ排出される酸素富化ガス（例えば、特許文献５参照）、製品窒素ガスの一部（例えば、特許文献３、４参照）が使用される。 To configure the cryogenic air separation process, it is necessary to supply cold so as to maintain the heat-cold balance, and for this purpose, an expansion turbine is used to supply process gas. The process gases used include a portion of the feed air (see, for example, Patent Documents 1 and 2), oxygen-enriched gas discharged outside the system as waste gas (see, for example, Patent Document 5), and a portion of the product nitrogen gas (see, for example, Patent Documents 3 and 4).

米国特許第５，２３１，８３７号U.S. Pat. No. 5,231,837 米国特許第１１，６７４，７５０号U.S. Pat. No. 11,674,750 特許第４５１５２２５号Patent No. 4515225 米国特許第５，２２８，２９７号U.S. Pat. No. 5,228,297 特開２０１７－７２２８２号公報JP 2017-72282 A

原料空気の一部を寒冷源とする場合、膨張された原料空気は、減圧されない原料空気が導入される精留塔（例えば第一精留塔）よりも低い圧力（例えば第二精留塔）で運転される精留塔に導入せざるを得ない。即ち、原料空気の大部分が導入される精留塔での窒素分離量が減じ、結果的に窒素発生装置の窒素回収率を減少させる。 When part of the feed air is used as the cold source, the expanded feed air must be introduced into a distillation tower that is operated at a lower pressure (e.g., the second distillation tower) than the distillation tower to which the unreduced feed air is introduced (e.g., the first distillation tower). In other words, the amount of nitrogen separated in the distillation tower to which most of the feed air is introduced is reduced, resulting in a decrease in the nitrogen recovery rate of the nitrogen generator.

酸素富化ガスを膨張させるプロセスの場合、カスケードプロセスにおいて、第一窒素凝縮器または第二窒素凝縮器から導出される酸素富化ガスが対象となる。第一窒素凝縮器からの酸素富化ガスは、第二窒素精留塔の底部に供給して第二窒素精留塔の蒸気流とすることができるので、寒冷源として使用するよりも、精留に寄与して窒素の回収量を増量させることが望ましい。第二窒素凝縮器から導出される酸素富化ガスは、窒素発生装置の窒素回収率を高めた場合、圧力が顕著に低下し、膨張して十分な寒冷を稼げるほどの圧力差が得られないので、特に高窒素回収率の窒素発生装置では主要な寒冷源とすることが難しい。 In the case of a process for expanding oxygen-enriched gas, the oxygen-enriched gas extracted from the first nitrogen condenser or the second nitrogen condenser in the cascade process is the target. The oxygen-enriched gas from the first nitrogen condenser can be supplied to the bottom of the second nitrogen rectification tower to become the vapor flow of the second nitrogen rectification tower, so it is preferable to contribute to the rectification and increase the amount of nitrogen recovered rather than using it as a cold source. When the nitrogen recovery rate of the nitrogen generator is increased, the pressure of the oxygen-enriched gas extracted from the second nitrogen condenser drops significantly, and a pressure difference sufficient to expand and provide sufficient cold cannot be obtained, so it is difficult to use it as a main cold source, especially in a nitrogen generator with a high nitrogen recovery rate.

窒素ガスを膨張させるプロセスの場合、既知の方法では第一製品窒素ガスと第二製品窒素ガスの圧力差を使用して寒冷を発生させる。膨張タービンによって得られる動力は、製品窒素ガス等のプロセスガス圧縮に使用することもできるし、発電機等を適用して動力を電力に変換することも可能である。 In the case of a process for expanding nitrogen gas, a known method uses the pressure difference between a first product nitrogen gas and a second product nitrogen gas to generate refrigeration. The power obtained by the expansion turbine can be used to compress a process gas, such as the product nitrogen gas, or the power can be converted to electricity, such as by applying a generator.

しかしながら製品窒素ガスは可能な限り減圧する量を最小化して、需要家に供給することが熱効率上望ましい。 However, from the standpoint of thermal efficiency, it is desirable to minimize the amount of pressure reduction required for the product nitrogen gas before supplying it to consumers.

上記の状況を鑑みて、本開示は、複式精留塔でのカスケードプロセスにおいて、昇圧膨張プロセスを利用して、第一精留塔から導出される製品窒素の回収率を低下させることなく、熱効率にも優れた窒素発生装置および窒素製造方法を提供する。
また、昇圧膨張プロセスに利用する、製品窒素ガス流量を最小化しつつ、窒素回収率と熱効率において優れた窒素発生装置および窒素製造方法を提供する。 In view of the above circumstances, the present disclosure provides a nitrogen generation apparatus and a nitrogen production method that utilize a pressurized expansion process in a cascade process in a double rectification column, thereby achieving excellent thermal efficiency without reducing the recovery rate of the product nitrogen extracted from a first rectification column.
The present invention also provides a nitrogen generator and a nitrogen production method that are excellent in nitrogen recovery rate and thermal efficiency while minimizing the flow rate of the product nitrogen gas used in the boost expansion process.

本開示の窒素発生装置（Ａ１、Ａ２、Ａ３）は、主熱交換器（１）と、第一窒素精留塔（２）と、第一窒素凝縮器（３）と、第二窒素精留塔（４）と、第二窒素凝縮器（５）と、第一窒素ブースター（７１）と、第一窒素膨張タービン（７２）と、冷却装置（８）を備える。
前記第一窒素ブースター（７１）と第一窒素膨張タービン（７２）は、第一窒素ブースタータービン（７）の構成であってもい。第一窒素ブースター（７１）は、第一窒素膨張タービン（７２）によって駆動されてもよい。
前記第一窒素ブースター（７１）は、前記第一窒素精留塔（２）の頂部（２３）から導出される第一窒素ガスの一部が、主熱交換器（１）へ導入され、温端から導出された第一製品窒素ガスの少なくとも一部を昇圧する。
前記冷却装置（８）は、前記第一窒素ブースター（７１）で昇圧された第一製品窒素ガスを所定の温度（例えば、約８０℃から約２０℃）へ冷却する。
前記第一窒素膨張タービン（７２）は、前記冷却装置（８）で冷却された後で、前記主熱交換器（１）の温端から再導入され、前記主熱交換器（１）の中間から導出された第一製品窒素ガスを膨張して冷却する。 The nitrogen generation apparatus (A1, A2, A3) of the present disclosure includes a main heat exchanger (1), a first nitrogen rectification column (2), a first nitrogen condenser (3), a second nitrogen rectification column (4), a second nitrogen condenser (5), a first nitrogen booster (71), a first nitrogen expansion turbine (72), and a cooling device (8).
The first nitrogen booster (71) and the first nitrogen expansion turbine (72) may be configured as a first nitrogen booster turbine (7). The first nitrogen booster (71) may be driven by the first nitrogen expansion turbine (72).
The first nitrogen booster (71) introduces a portion of the first nitrogen gas discharged from the top (23) of the first nitrogen rectification column (2) into the main heat exchanger (1), and boosts the pressure of at least a portion of the first product nitrogen gas discharged from the warm end.
The cooling device (8) cools the first product nitrogen gas pressurized by the first nitrogen booster (71) to a predetermined temperature (for example, from about 80° C. to about 20° C.).
The first nitrogen expansion turbine (72) expands and cools the first product nitrogen gas, which is reintroduced from the warm end of the main heat exchanger (1) after being cooled by the cooling device (8) and discharged from the middle of the main heat exchanger (1).

前記窒素発生装置（Ａ１、Ａ２、Ａ３）は、サブクーラ（６）を備えていてもよい。
前記サブクーラ（６）は、前記主熱交換器（１）と一体的な連結構造であってもよく、別体の構造であってもよい。
前記サブクーラ（６）は、前記第一窒素精留塔（２）の底部（２１）から前記第二窒素精留塔（４）の精留部（４２）の中間段へ供給される第一酸素富化液を冷却してもよい。
前記サブクーラ（６）は、前記第一窒素凝縮器（３）から前記第二窒素精留塔（４）の頂部（４３）あるいは気相部へ供給される第一液化窒素（第一窒素精留塔（２）の頂部の気相からの蒸気流を第一窒素凝縮器（３）で凝縮されて第一窒素精留塔（２）へ戻る還流液の一部）を冷却してもよい。
前記サブクーラ（６）は、前記第一窒素凝縮器（３）の冷媒貯留部（３１）から前記第二窒素凝縮器（５）の冷媒貯留部（５１）へ送られる冷媒である第二酸素富化液を冷却してもよい。
前記サブクーラ（６）は、前記第一窒素精留塔（２）の頂部の気相から第一窒素凝縮器（３）へ送られる蒸気流である第一窒素ガス（蒸気流の一部でもよい）を冷却してもよい。冷却された第一窒素ガスは、前記主熱交換器（１）の冷端へ導入され、温端から第一製品窒素ガスとして導出されてもよい。温端から導出された第一製品窒素ガスの一部は、前記第一窒素ブースター（７１）へ送られてもよい。
前記サブクーラ（６）は、前記第二窒素精留塔（４）の頂部の気相から第二窒素凝縮器（５）へ送られる蒸気流である第二窒素ガス（蒸気流の一部でもよい）を冷却してもよい。冷却されてた第二窒素ガスは、前記主熱交換器（１）の冷端へ導入され、温端から、第二製品窒素ガスとして導出されてもよい。
前記サブクーラ（６）は、前記第二窒素凝縮器（５）の気相から導出される第二酸素富化ガスを冷却してもよい。冷却された第二酸素富化ガスは、前記熱交換器（１）の冷端へ導入され、温端から、廃ガスとして導出されてもよい。 The nitrogen generator (A1, A2, A3) may be equipped with a subcooler (6).
The subcooler (6) may be an integrally connected structure with the main heat exchanger (1) or may be a separate structure.
The subcooler (6) may cool a first oxygen-enriched liquid that is fed from the bottom (21) of the first nitrogen rectifier (2) to an intermediate stage of the rectification section (42) of the second nitrogen rectifier (4).
The subcooler (6) may cool the first liquefied nitrogen (a part of the reflux liquid which is a vapor stream from the gas phase at the top of the first nitrogen rectification column (2) condensed in the first nitrogen condenser (3) and returned to the first nitrogen rectification column (2)) supplied from the first nitrogen condenser (3) to the top (43) or the gas phase of the second nitrogen rectification column (4).
The subcooler (6) may cool a second oxygen-enriched liquid, which is a refrigerant sent from the refrigerant reservoir (31) of the first nitrogen condenser (3) to the refrigerant reservoir (51) of the second nitrogen condenser (5).
The subcooler (6) may cool a first nitrogen gas (or a part of the vapor stream) which is a vapor stream sent from the vapor phase at the top of the first nitrogen rectification column (2) to the first nitrogen condenser (3). The cooled first nitrogen gas may be introduced into the cold end of the main heat exchanger (1) and discharged from the warm end as a first product nitrogen gas. A part of the first product nitrogen gas discharged from the warm end may be sent to the first nitrogen booster (71).
The subcooler (6) may cool the second nitrogen gas (which may be a part of the vapor stream) which is a vapor stream sent from the vapor phase at the top of the second nitrogen rectification column (4) to the second nitrogen condenser (5). The cooled second nitrogen gas may be introduced into the cold end of the main heat exchanger (1) and discharged from the warm end as second product nitrogen gas.
The subcooler (6) may cool the second oxygen-enriched gas exiting the gas phase of the second nitrogen condenser (5). The cooled second oxygen-enriched gas may be introduced into the cold end of the heat exchanger (1) and exited from the warm end as waste gas.

前記窒素発生装置（Ａ１、Ａ２）は、第二酸素富化ガス膨張タービン（９）を備えていてもよい。
前記第二酸素富化ガス膨張タービン（９）は、前記第二窒素精留塔（４）の頂部（４３）の気相から導出される第二酸素富化ガスを、前記サブクーラ（６）および／または前記主熱交換器（１）で冷却した後で、膨張し冷却する。膨張し冷却した第二酸素富化ガスは、前記主熱交換器（１）へ再度導入し、温端から廃ガスとして排出されてもよい。 The nitrogen generator (A1, A2) may comprise a second oxygen-enriched gas expansion turbine (9).
The second oxygen-enriched gas expansion turbine (9) expands and cools the second oxygen-enriched gas discharged from the vapor phase at the top (43) of the second nitrogen rectification column (4) after it has been cooled in the subcooler (6) and/or the main heat exchanger (1). The expanded and cooled second oxygen-enriched gas may be reintroduced into the main heat exchanger (1) and discharged as waste gas from the warm end.

本開示の上記窒素発生装置（Ａ１、Ａ２、Ａ３）を用いた窒素製造方法は、
第一窒素精留塔（２）の頂部（２３）から導出される第一窒素ガスの一部（蒸気流の一部）が、主熱交換器（１）の冷端から導入され温端から導出され、温端から導出された第一製品窒素ガスの少なくとも一部が、第一窒素ブースター（７１）で昇圧され、冷却装置（８）で冷却された後で、前記主熱交換器（１）の温端から再導入され、前記主熱交換器（１）の中間から導出されて第一窒素膨張タービン（７２）で膨張して冷却されるステップを含む。
この構成では、主熱交換器（１）に再導入されることによって、主熱交換器（１）を冷却して窒素発生装置（Ａ１）の運転に必要な寒冷を供給することができる。 The nitrogen production method using the nitrogen generation apparatus (A1, A2, A3) of the present disclosure includes the following steps:
The method includes a step in which a portion of the first nitrogen gas (a portion of the vapor stream) discharged from the top (23) of the first nitrogen rectification column (2) is introduced into a cold end of a main heat exchanger (1) and discharged from the warm end, and at least a portion of the first product nitrogen gas discharged from the warm end is pressurized in a first nitrogen booster (71), cooled in a cooling device (8), and then reintroduced into the warm end of the main heat exchanger (1), discharged from the middle of the main heat exchanger (1), and expanded and cooled in a first nitrogen expansion turbine (72).
In this configuration, by being reintroduced into the main heat exchanger (1), it is possible to cool the main heat exchanger (1) and supply the refrigeration required for the operation of the nitrogen generation apparatus (A1).

前記窒素製造方法は、
前記第一窒素膨張タービン（７２）で膨張され減圧され、主熱交換器（１）に再導入された第一製品窒素ガスを、第二窒素精留塔（４）の頂部（４３）から導出され主熱交換器（１）の内の第二窒素ガスと合流し、前記主熱交換器（１）で別物質（例えば、原料空気など）を冷却するステップを含んでいてもよく、また、
前記第一窒素膨張タービン（７２）で膨張され減圧され、前記主熱交換器（１）に再導入された第一製品窒素ガスで、主熱交換器（１）で別物質（例えば、原料空気など）を冷却し、および前記第二窒素精留塔（４）の頂部から導出され主熱交換器（１）へ導入された第二製品窒素ガスで、主熱交換器（１）で別物質（例えば、原料空気など）を冷却するステップを含んでいてもよい。 The nitrogen production method includes:
The first product nitrogen gas expanded and decompressed in the first nitrogen expansion turbine (72) and reintroduced into the main heat exchanger (1) may be combined with the second nitrogen gas discharged from the top (43) of the second nitrogen rectification column (4) in the main heat exchanger (1), and another substance (e.g., feed air, etc.) may be cooled in the main heat exchanger (1),
The method may include a step of cooling another substance (e.g., feed air, etc.) in the main heat exchanger (1) with a first product nitrogen gas expanded and reduced in pressure in the first nitrogen expansion turbine (72) and reintroduced into the main heat exchanger (1), and cooling another substance (e.g., feed air, etc.) in the main heat exchanger (1) with a second product nitrogen gas discharged from the top of the second nitrogen rectification column (4) and introduced into the main heat exchanger (1).

前記窒素製造方法は、
前記第二窒素凝縮器（５）の気相から導出される第二酸素富化ガスを、前記サブクーラ（６）を通過させ、前記主熱交換器（１）に導入し、中間部から導出した後で、第二酸素富化ガス膨張タービン（９）で膨張し冷却し、膨張し冷却した第二酸素富化ガスを、前記主熱交換器（１）へ再度導入し、温端から廃ガスとして排出するステップを含んでいてもよい。 The nitrogen production method includes:
The method may further include a step of passing the second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser (5) through the subcooler (6), introducing it into the main heat exchanger (1), discharging it from an intermediate section, and then expanding and cooling it in a second oxygen-enriched gas expansion turbine (9), and reintroducing the expanded and cooled second oxygen-enriched gas into the main heat exchanger (1) and discharging it from a warm end as waste gas.

本開示の窒素発生装置（Ａ１、Ａ２、Ａ３）は、
原料空気が原料空気ライン（Ｌ１）を介して導入される主熱交換器（１）と、
前記主熱交換器（１）で熱交換された原料空気が原料空気ライン（Ｌ１）を介して導入される精留部（２２）あるいは底部（２１）を有する第一窒素精留塔（２）と、
前記第一窒素精留塔（２）の頂部（２３）から導出される第一窒素ガス（蒸気流）を、第一凝縮還流ライン（Ｌ２３１）を介して凝縮し、還流液として前記第一窒素精留塔（２）へ戻す第一窒素凝縮器（３）と、
前記第一窒素精留塔（２）の頂部（２３）から導出される第一窒素ガス（蒸気流）を、（サブクーラ６を通過した後で）少なくとも前記主熱交換器（１）の冷端へ導入し、温端から導出して、第一製品窒素ガスとして取り出す第一製品窒素ガスライン（Ｌ２３）と、
前記第一製品窒素ガスライン（Ｌ２３）の前記主熱交換器（１）の温端よりも下流側から分岐する第一製品窒素分岐ライン（Ｌ２３ａ）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第一製品窒素ガスを昇圧する第一窒素ブースター（７１）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第一窒素ブースター（７１）で昇圧された第一製品窒素ガスを所定温度へ冷却する冷却装置（８）と、
前記冷却装置（８）で冷却された前記第一製品窒素ガスを、前記主熱交換器（１）の温端から導入し、中間部から導出し、膨張し冷却する第一窒素膨張タービン（７２）と、
前記第一窒素凝縮器（３）からの蒸気流が導入される、第二窒素精留塔（４）と、
前記第二窒素精留塔（４）の頂部（４３）から導出される第二窒素ガス（蒸気流）を、第二凝縮還流ライン（Ｌ２３１）を介して凝縮し、還流液として前記第二窒素精留塔（４）へ戻す第二窒素凝縮器（５）と、
前記第二窒素精留塔（４）の頂部（４３）から導出される第二窒素ガス（蒸気流）を、（サブクーラ６を通過した後で）少なくとも前記主熱交換器（１）の冷端へ導入し、温端から導出して、第二製品窒素ガスとして取り出す第二製品窒素ガスライン（Ｌ４３）と、
を備えていてもよい。 The nitrogen generation apparatus (A1, A2, A3) of the present disclosure is
a main heat exchanger (1) into which feed air is introduced via a feed air line (L1);
a first nitrogen rectification column (2) having a rectification section (22) or a bottom section (21) into which the feed air heat-exchanged in the main heat exchanger (1) is introduced via a feed air line (L1);
a first nitrogen condenser (3) for condensing a first nitrogen gas (vapor stream) discharged from a top (23) of the first nitrogen rectification column (2) through a first condensate reflux line (L231) and returning the first nitrogen gas (vapor stream) as a reflux liquid to the first nitrogen rectification column (2);
a first product nitrogen gas line (L23) for introducing the first nitrogen gas (vapor stream) discharged from the top (23) of the first nitrogen rectification column (2) (after passing through a subcooler 6) into at least the cold end of the main heat exchanger (1) and discharging it from the warm end as a first product nitrogen gas;
a first product nitrogen branch line (L23a) branching off from the first product nitrogen gas line (L23) downstream of the warm end of the main heat exchanger (1);
a first nitrogen booster (71) provided in the first product nitrogen branch line (L23a) for boosting the pressure of the first product nitrogen gas;
a cooling device (8) provided in the first product nitrogen branch line (L23a) for cooling the first product nitrogen gas pressurized by the first nitrogen booster (71) to a predetermined temperature;
a first nitrogen expansion turbine (72) which introduces the first product nitrogen gas cooled by the cooling device (8) from a warm end of the main heat exchanger (1), discharges it from an intermediate portion, and expands and cools it;
a second nitrogen rectification column (4) into which the vapor stream from the first nitrogen condenser (3) is introduced;
a second nitrogen condenser (5) for condensing the second nitrogen gas (vapor stream) discharged from the top (43) of the second nitrogen rectification column (4) through a second condensation reflux line (L231) and returning the second nitrogen gas (vapor stream) as a reflux liquid to the second nitrogen rectification column (4);
a second product nitrogen gas line (L43) for introducing the second nitrogen gas (vapor stream) discharged from the top (43) of the second nitrogen rectification column (4) (after passing through a subcooler 6) into at least the cold end of the main heat exchanger (1) and discharging it from the warm end as a second product nitrogen gas;
The device may include:

前記窒素発生装置（Ａ１、Ａ２、Ａ３）において、
前記第一製品窒素ガスは、前記第一窒素膨張タービン（７２）で仕事させた後で、前記主熱交換器（１）に再度導入し、第二製品窒素ライン（Ｌ４３）へ合流させて、第二製品窒素ガスとして取り出されてもよい。第一製品窒素分岐ライン（Ｌ２３ａ）は、第二製品窒素ライン（Ｌ４３）と、主熱交換器（１）の中で合流してもよい。 In the nitrogen generating apparatus (A1, A2, A3),
The first product nitrogen gas may be reintroduced into the main heat exchanger (1) after being worked in the first nitrogen expansion turbine (72), merged with the second product nitrogen line (L43), and taken out as a second product nitrogen gas. The first product nitrogen branch line (L23a) may merge with the second product nitrogen line (L43) in the main heat exchanger (1).

前記窒素発生装置（Ａ１、Ａ２、Ａ３）は、
前記主熱交換器（１）と連結される、あるいは主熱交換器（１）とは別体のサブクーラ（６）と、
前記第一窒素精留塔（２）の底部（２１）から導出される第一酸素富化液を、前記サブクーラ（６）へ導入して導出し、前記第二窒素精留塔（４）の精留部（４２）の中間段へ導入する第一酸素富化液ライン（Ｌ２１）と、
前記第一窒素凝縮器（３）で凝縮された第一液化窒素を、前記サブクーラ（６）へ導入して導出し、前記第二窒素精留塔（４）の頂部（４３）へ導入する第一液化窒素ライン（Ｌ２３１ａ）と、
前記第一窒素凝縮器（３）の冷媒貯留部（３１）から導出される第二酸素富化液を、前記サブクーラ（６）へ導入して導出し、前記第二窒素凝縮器（５）の冷媒貯留部（５１）へ導入する第二酸素富化液ライン（Ｌ３１）と、を備えていてもよい。 The nitrogen generators (A1, A2, A3) are
a subcooler (6) connected to the main heat exchanger (1) or separate from the main heat exchanger (1);
a first oxygen-enriched liquid line (L21) for introducing the first oxygen-enriched liquid discharged from the bottom (21) of the first nitrogen rectification column (2) into the subcooler (6) and for introducing the first oxygen-enriched liquid into an intermediate stage of the rectification section (42) of the second nitrogen rectification column (4);
a first liquefied nitrogen line (L231a) for introducing the first liquefied nitrogen condensed in the first nitrogen condenser (3) into the subcooler (6) and for introducing the first liquefied nitrogen into the top (43) of the second nitrogen rectification column (4);
and a second oxygen-enriched liquid line (L31) through which the second oxygen-enriched liquid discharged from the refrigerant reservoir (31) of the first nitrogen condenser (3) is introduced into the subcooler (6) and then introduced into the refrigerant reservoir (51) of the second nitrogen condenser (5).

前記窒素発生装置（Ａ１）は、
前記第二窒素凝縮器（５）の気相から導出される第二酸素富化ガスを、前記サブクーラ（６）へ導入して導出し、冷却された第二酸素富化ガスを、前記主熱交換器（１）の冷端へ導入され、温端から、廃ガスとして導出する第一廃ガスライン（Ｌ５３）を備えていてもよい。 The nitrogen generator (A1) comprises:
The system may also include a first waste gas line (L53) through which the second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser (5) is introduced into the subcooler (6) and discharged, and the cooled second oxygen-enriched gas is introduced into the cold end of the main heat exchanger (1) and discharged from the warm end as waste gas.

前記窒素発生装置（Ａ２）は、
前記廃ガスライン（Ｌ５３）が、前記主熱交換器（１）の中間部から導出され、再度、主熱交換器（１）へ導入されて、温端から出るように延設されており、
前記中間部から導出された位置に、第二酸素富化ガス膨張タービン（９）を備え、
前記第二酸素富化ガス膨張タービン（９）で、第二酸素富化ガスを膨張し冷却させて、前記主熱交換器（１）へ再度送る構成であってもよい。
前記窒素発生装置（Ａ２）は、
前記第二窒素凝縮器（５）の気相から導出される第二酸素富化ガスを、前記サブクーラ（６）を通過させ、前記主熱交換器（１）に導入し、中間部から導出した後で、第二酸素富化ガス膨張タービン（９）で膨張し冷却し、膨張し冷却した第二酸素富化ガスを、前記主熱交換器（１）へ再度導入し、温端から廃ガスとして排出する第二廃ガスライン（Ｌ５３１）を備えていてもよい。 The nitrogen generator (A2) comprises:
The waste gas line (L53) is led out from an intermediate portion of the main heat exchanger (1), re-introduced into the main heat exchanger (1), and extended so as to exit from the warm end,
a second oxygen-enriched gas expansion turbine (9) disposed at a position derived from the intermediate portion;
The second oxygen-enriched gas may be expanded and cooled in the second oxygen-enriched gas expansion turbine (9) and sent again to the main heat exchanger (1).
The nitrogen generator (A2) comprises:
The second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser (5) is passed through the subcooler (6), introduced into the main heat exchanger (1), discharged from an intermediate section, and then expanded and cooled in a second oxygen-enriched gas expansion turbine (9). A second waste gas line (L531) is provided through which the expanded and cooled second oxygen-enriched gas is reintroduced into the main heat exchanger (1) and discharged from a warm end as waste gas.

前記窒素発生装置（Ａ３）は、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられる窒素圧縮機（７１１）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記窒素圧縮機（７１１）で圧縮された第一製品窒素ガスを冷却する第三冷却装置（８１）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第三冷却装置（８１）で冷却された前記第一製品窒素ガスを昇圧する第二窒素ブースター（７１ａ）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第二窒素ブースター（７１ａ）で昇圧された第一製品窒素ガスを所定温度へ冷却する第二冷却装置（８ａ）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第二冷却装置（８ａ）で冷却された前記第一製品窒素ガスを昇圧する第一窒素ブースター（７１）と、
前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられ、前記第一窒素ブースター（７１）で昇圧された第一製品窒素ガスを所定温度へ冷却する第一冷却装置（８）と、
前記主熱交換器（１）の冷端より下流の前記第一製品窒素分岐ライン（Ｌ２３ａ）に設けられる減圧弁（１０９）と、
前記減圧弁（１０９）より下流に設けられ、ガス分と液分に分離する気液分離器（１１０）と、
を備えていてもよい。
前記窒素発生装置（Ａ３）は、
前記第二窒素ブースター（７１ａ）より上流の第一製品窒素分岐ライン（Ｌ２３ａ）から分岐して前記第一製品窒素ガスの一部を導出し、前記主熱交換器（１）の温端から導入し、第一中間部（１ａ）から導出される前記第一製品窒素ガスを、膨張し冷却する第二窒素膨張タービン（７２ａ）と、
前記第一冷却装置（８）で冷却され、前記主熱交換器（１）の温端から導入し、前記第一中間部（１ａ）よりも冷端側の第二中間部（１ｂ）から導出される第一製品窒素ガスの一部を、膨張し冷却する第一窒素膨張タービン（７２）と、
を備えていてもよい。
前記窒素発生装置（Ａ３）の前記第一製品窒素分岐ライン（Ｌ２３ａ）は、
窒素圧縮機（７１１）、第三冷却装置（８１）、第二窒素ブースター（７１ａ）、第二冷却装置（８ａ）、第一窒素ブースター（７１）、第一冷却装置（８）を介して、その後に、主熱交換器（１）の温端から導入し、冷端から導出し、その後に、減圧弁（１０９）を介して、気液分離器（１１０）へ導入するためのラインであってもよい。
前記窒素発生装置（Ａ３）は、
前記第二窒素ブースター（７１ａ）より上流の前記第一製品窒素分岐ライン（Ｌ２３ａ）から分岐して前記第一製品窒素ガスの一部を導出し、前記主熱交換器（１）の温端から導入し、第一中間部（１ａ）から導出し、前記第二窒素膨張タービン（７２ａ）で仕事をさせた後で、再び前記主熱交換器（１）の中間部へ導入し、前記主熱交換器（１）の中で、前記第二製品窒素ライン（Ｌ４３）と合流するための第一製品窒素第二分岐ライン（Ｌ２３ｂ）と、
前記主熱交換器（１）の内部の前記第一製品窒素分岐ライン（Ｌ２３ａ）から分岐して前記第一製品窒素ガスの一部を前記主熱交換器（１）の前記第一中間部（１ａ）よりも冷端側の第二中間部（１ｂ）から導出し、前記第一窒素膨張タービン（７２）で前記第一製品窒素ガスを膨張し冷却し、前記主熱交換器（１）へ再度送る（あるいは前記主熱交換器（１）の冷端より上流の前記第二製品窒素ライン（Ｌ４３）へ合流する）ための第一製品窒素第三分岐ライン（Ｌ２３ｃ）と、
を備えていてもよい。
前記第二窒素ブースター（７１ａ）と前記第二窒素膨張タービン（７２ａ）とで、第二窒素ブースタータービン（７ａ）成し、前記第一窒素ブースター（７１）と前記第一窒素膨張タービン（７２）とで、第一窒素ブースタータービン（７）を構成してもよい。 The nitrogen generator (A3) comprises:
A nitrogen compressor (711) provided in the first product nitrogen branch line (L23a);
a third cooling device (81) provided in the first product nitrogen branch line (L23a) for cooling the first product nitrogen gas compressed by the nitrogen compressor (711);
a second nitrogen booster (71a) provided in the first product nitrogen branch line (L23a) for boosting the pressure of the first product nitrogen gas cooled in the third cooling device (81);
a second cooling device (8a) provided in the first product nitrogen branch line (L23a) for cooling the first product nitrogen gas pressurized by the second nitrogen booster (71a) to a predetermined temperature;
a first nitrogen booster (71) provided in the first product nitrogen branch line (L23a) for boosting the pressure of the first product nitrogen gas cooled in the second cooling device (8a);
a first cooling device (8) provided in the first product nitrogen branch line (L23a) for cooling the first product nitrogen gas pressurized by the first nitrogen booster (71) to a predetermined temperature;
a pressure reducing valve (109) provided in the first product nitrogen branch line (L23a) downstream of the cold end of the main heat exchanger (1);
a gas-liquid separator (110) provided downstream of the pressure reducing valve (109) for separating the gas and liquid components;
The device may include:
The nitrogen generator (A3) comprises:
a second nitrogen expansion turbine (72a) which expands and cools a portion of the first product nitrogen gas branched from a first product nitrogen branch line (L23a) upstream of the second nitrogen booster (71a), which is introduced from a warm end of the main heat exchanger (1), and which is discharged from a first intermediate section (1a);
a first nitrogen expansion turbine (72) for expanding and cooling a portion of the first product nitrogen gas that has been cooled by the first cooling device (8), introduced from a warm end of the main heat exchanger (1), and discharged from a second intermediate section (1b) located on the cold end side of the first intermediate section (1a);
The device may include:
The first product nitrogen branch line (L23a) of the nitrogen generation apparatus (A3) is
The line may be a line for introducing the nitrogen gas through a nitrogen compressor (711), a third cooling device (81), a second nitrogen booster (71a), a second cooling device (8a), a first nitrogen booster (71), and a first cooling device (8) from a warm end of the main heat exchanger (1) and discharging the same from a cold end thereof, and then introducing the same through a pressure reducing valve (109) into a gas-liquid separator (110).
The nitrogen generator (A3) comprises:
a first product nitrogen second branch line (L23b) for branching off from the first product nitrogen branch line (L23a) upstream of the second nitrogen booster (71a) to discharge a portion of the first product nitrogen gas, introducing it from the warm end of the main heat exchanger (1), discharging it from the first intermediate section (1a), making it work in the second nitrogen expansion turbine (72a), and then introducing it again into the intermediate section of the main heat exchanger (1) to join the second product nitrogen line (L43) in the main heat exchanger (1);
a first product nitrogen third branch line (L23c) which branches off from the first product nitrogen branch line (L23a) inside the main heat exchanger (1) and outputs a portion of the first product nitrogen gas from a second intermediate section (1b) located on the cold end side of the first intermediate section (1a) of the main heat exchanger (1), expands and cools the first product nitrogen gas in the first nitrogen expansion turbine (72), and sends it again to the main heat exchanger (1) (or joins the second product nitrogen line (L43) upstream of the cold end of the main heat exchanger (1));
The device may include:
The second nitrogen booster (71a) and the second nitrogen expansion turbine (72a) may constitute a second nitrogen booster turbine (7a), and the first nitrogen booster (71) and the first nitrogen expansion turbine (72) may constitute a first nitrogen booster turbine (7).

前記第一製品窒素ガスの圧力は、第二製品窒素ガスの圧力よりも小さくてもよい。
前記窒素発生装置（Ａ１、Ａ２、Ａ３）は、
流量測量器、圧力測定器、温度測定器、液レベル測定器などの各種計測器と、
制御弁、仕切弁などの各種弁と、
各要素間を連結する配管と、
を有していてもよい。 The pressure of the first product nitrogen gas may be less than the pressure of the second product nitrogen gas.
The nitrogen generators (A1, A2, A3) are
Various measuring instruments such as flow rate measuring instruments, pressure measuring instruments, temperature measuring instruments, and liquid level measuring instruments,
Various valves such as control valves and gate valves,
Piping that connects each element;
[0043]

（作用効果）
（１）第一窒素ブースタータービンの構成による寒冷発生を行える。第一製品窒素ガスの一部は、第一膨張タービンによって駆動される第一窒素ブースターよって第一製品窒素ガスの圧力より高い圧力に昇圧されてから、膨張される。この昇圧プロセスは、第一膨張タービンにおける圧力差を大きくすることで、流量あたりの発生寒冷量を高めることができ、結果的に寒冷発生に要する窒素モル流量を低減することができる。さらに、大きな圧力差が得られることで、目的の温度まで窒素ガスを冷却する場合、より高い温度で窒素ガスを第一膨張タービンに導入することができるため、寒冷の発生に有利に働くことになる。
（２）サブクーラの作用により、プロセス液をより低い温度のプロセスガスでサブクールし、減圧時のガス化量を抑制し、精留プロセスに寄与する液量を増量することで、窒素回収率の向上に貢献する。
（３）第二酸素富化ガス膨張タービンの作用により、第二酸素富化ガスを補助的な寒冷源として利用することができ、これにより、第一窒素ブースタータービンへ送る第一製品窒素ガスの量を下げることができる。
（４） (Action and Effect)
(1) Chilling can be generated by the configuration of a first nitrogen booster turbine. A part of the first product nitrogen gas is boosted to a pressure higher than the pressure of the first product nitrogen gas by the first nitrogen booster driven by the first expansion turbine, and then expanded. This boosting process can increase the amount of refrigeration generated per flow rate by increasing the pressure difference in the first expansion turbine, and as a result, the nitrogen molar flow rate required for refrigeration generation can be reduced. Furthermore, by obtaining a large pressure difference, when the nitrogen gas is cooled to the target temperature, the nitrogen gas can be introduced into the first expansion turbine at a higher temperature, which is advantageous for the generation of refrigeration.
(2) The subcooler function subcools the process liquid with a lower temperature process gas, suppressing the amount of gasification during pressure reduction and increasing the amount of liquid contributing to the rectification process, thereby contributing to an improvement in the nitrogen recovery rate.
(3) The operation of the second oxygen-enriched gas expansion turbine allows the second oxygen-enriched gas to be used as an auxiliary refrigeration source, thereby reducing the amount of first product nitrogen gas sent to the first nitrogen booster turbine.
(4)

実施形態１の窒素発生装置を示す図である。FIG. 1 is a diagram showing a nitrogen generating apparatus according to a first embodiment. 実施形態２の窒素発生装置を示す図である。FIG. 13 is a diagram showing a nitrogen generating apparatus according to a second embodiment. 実施形態３の窒素発生装置を示す図である。FIG. 11 is a diagram showing a nitrogen generating apparatus according to a third embodiment.

以下に本開示のいくつかの実施形態について説明する。以下に説明する実施形態は、本開示の一例を説明するものである。本開示は以下の実施形態になんら限定されるものではなく、本開示の要旨を変更しない範囲において実施される各種の変形形態も含む。なお、以下で説明される構成の全てが本開示の必須の構成であるとは限らない。上流や下流は流体の流れ方向を基準にしている。 Several embodiments of the present disclosure are described below. The embodiments described below are examples of the present disclosure. The present disclosure is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present disclosure. Note that not all of the configurations described below are essential configurations of the present disclosure. Upstream and downstream are based on the flow direction of the fluid.

（実施形態１）
実施形態１の窒素発生装置Ａ１を図１を用いて説明する。
窒素製発生置Ａ１は、主熱交換器１と、第一窒素精留塔２と、第一窒素凝縮器３と、第二窒素精留塔４と、第二窒素凝縮器５と、サブクーラ６と、第一窒素ブースタータービン７と、冷却装置８を備える。
本実施形態では、サブクーラ６と主熱交換器１とは一体的な連結構造である。分離ラインを一点鎖線Ｓで示す。また、第一窒素ブースタータービン７は、第一窒素ブースター７１と、第一窒素膨張タービン７２を備え、第一窒素ブースター７１は、第一窒素膨張タービン７２によって駆動される。 (Embodiment 1)
The nitrogen generating apparatus A1 of the first embodiment will be described with reference to FIG.
The nitrogen generation apparatus A1 includes a main heat exchanger 1, a first nitrogen rectification column 2, a first nitrogen condenser 3, a second nitrogen rectification column 4, a second nitrogen condenser 5, a subcooler 6, a first nitrogen booster turbine 7, and a cooling device 8.
In this embodiment, the subcooler 6 and the main heat exchanger 1 have an integrally connected structure. A separation line is indicated by a dashed dotted line S. The first nitrogen booster turbine 7 includes a first nitrogen booster 71 and a first nitrogen expansion turbine 72, and the first nitrogen booster 71 is driven by the first nitrogen expansion turbine 72.

主熱交換器１は、温端から導入された原料空気を冷却し、冷端から導出する。冷却された原料空気は、原料空気ラインＬ１を介して窒素精留塔２へ導入される。
第一窒素精留塔２は、底部２１と、精留部２２と、頂部２３を備える。原料空気ラインＬ１は、底部２１に接続される。
底部２１に貯留された酸素富化液は、第一酸素富化液ラインＬ２１を介して、サブクーラ６へ送られ、次いで、第二窒素精留塔４の精留部４２の中間部へ送られる。 The main heat exchanger 1 cools the feed air introduced from the hot end and discharges it from the cold end. The cooled feed air is introduced into the nitrogen rectification column 2 via the feed air line L1.
The first nitrogen rectification column 2 comprises a bottom 21, a rectification section 22, and a top 23. The feed air line L1 is connected to the bottom 21.
The oxygen-enriched liquid stored in the bottom 21 is sent to the subcooler 6 via the first oxygen-enriched liquid line L21, and then sent to an intermediate portion of the rectification section 42 of the second nitrogen rectification column 4.

第一窒素凝縮器３は、頂部２３の上方に設けられる。第一窒素凝縮器３は、第一窒素精留塔２の頂部２３から導出される第一窒素ガス（蒸気流）が第一凝縮還流ラインＬ２３１を介して導入され、酸素富化液との熱交換によって冷却（凝縮）し液化窒素にする。液化窒素は還流液として第一窒素精留塔２の頂部２３へ戻る。
第一液化窒素ラインＬ２３１ａは、第一凝縮還流ラインＬ２３１から分岐する。第一液化窒素ラインＬ２３１ａは、第一窒素凝縮器３で凝縮された第一液化窒素を、サブクーラ６へ導入して導出し、第二窒素精留塔４の頂部４３へ導入するラインである。
第二酸素富化液ラインＬ３１は、第一窒素凝縮器３の冷媒貯留部３１から導出される第二酸素富化液を、サブクーラ６へ導入して導出し、第二窒素凝縮器５の冷媒貯留部５１へ導入するラインである。 The first nitrogen condenser 3 is provided above the top 23. The first nitrogen condenser 3 receives the first nitrogen gas (vapor flow) discharged from the top 23 of the first nitrogen rectification column 2 via the first condensate reflux line L231, and cools (condenses) the first nitrogen gas by heat exchange with the oxygen-enriched liquid to produce liquefied nitrogen. The liquefied nitrogen returns to the top 23 of the first nitrogen rectification column 2 as a reflux liquid.
The first liquefied nitrogen line L231a branches off from the first condensate reflux line L231. The first liquefied nitrogen line L231a is a line through which the first liquefied nitrogen condensed in the first nitrogen condenser 3 is introduced into the subcooler 6, discharged therefrom, and introduced into the top 43 of the second nitrogen rectification column 4.
The second oxygen-enriched liquid line L31 is a line that introduces the second oxygen-enriched liquid discharged from the refrigerant reservoir 31 of the first nitrogen condenser 3 to the subcooler 6, and then introduces it into the refrigerant reservoir 51 of the second nitrogen condenser 5.

第一製品窒素ガスラインＬ２３は、第一窒素精留塔２の頂部２３から導出される第一窒素ガス（蒸気流）を、サブクーラ６を通過した後で、主熱交換器１の冷端へ導入し、温端から導出して、第一製品窒素として取り出すラインである。
第一窒素精留塔２の頂部２３から導出される第一製品窒素ガス（蒸気流）は、第一製品窒素ガスラインＬ２３を介して、サブクーラ６へ送られ、その中間部から導出されて主熱交換器１の冷端から導入され、温端から導出されて高圧窒素ガスとして導出される。
第一窒素ブースター７１は、第一製品窒素ガスラインＬ２３の主熱交換器１の温端より下流側から分岐した第一製品窒素ガスは、第一製品窒素分岐ラインＬ２３ａを介して導入されて、第一製品窒素ガスを昇圧する。 The first product nitrogen gas line L23 is a line through which the first nitrogen gas (vapor flow) discharged from the top 23 of the first nitrogen rectification column 2 is introduced into the cold end of the main heat exchanger 1 after passing through the subcooler 6, and discharged from the warm end thereof as first product nitrogen.
The first product nitrogen gas (vapor flow) discharged from the top 23 of the first nitrogen rectification column 2 is sent to the subcooler 6 via the first product nitrogen gas line L23, discharged from the intermediate portion thereof, introduced into the cold end of the main heat exchanger 1, and discharged from the warm end as high-pressure nitrogen gas.
The first nitrogen booster 71 introduces the first product nitrogen gas branched off from the first product nitrogen gas line L23 downstream of the warm end of the main heat exchanger 1 via the first product nitrogen branch line L23a, and boosts the pressure of the first product nitrogen gas.

冷却装置８は、第一窒素ブースター７１で昇圧された第一製品窒素を、第一製品窒素分岐ラインＬ２３ａを介して導入されて、所定温度へ冷却する。冷却された第一製品窒素は、主熱交換器１の温端へ再導入され、中間部から導出される。 The cooling device 8 cools the first product nitrogen pressurized by the first nitrogen booster 71 to a predetermined temperature by introducing it through the first product nitrogen branch line L23a. The cooled first product nitrogen is reintroduced into the warm end of the main heat exchanger 1 and discharged from the middle section.

第一窒素膨張タービン７２は、第一製品窒素分岐ラインＬ２３ａを介して主熱交換器１の中間部から導出した第一製品窒素を膨張し冷却する。膨張された第一製品窒素は、再び、第一製品窒素分岐ラインＬ２３ａを介して主熱交換器１の中間部へ導入され、温端から導出される。図１では、主熱交換器１の内部で第二製品窒素ガスラインＬ４３へ合流する。 The first nitrogen expansion turbine 72 expands and cools the first product nitrogen discharged from the middle part of the main heat exchanger 1 via the first product nitrogen branch line L23a. The expanded first product nitrogen is again introduced into the middle part of the main heat exchanger 1 via the first product nitrogen branch line L23a and discharged from the warm end. In FIG. 1, it merges with the second product nitrogen gas line L43 inside the main heat exchanger 1.

第二窒素精留塔４は、第一窒素凝縮部３の気相からの蒸気流が導入され、精留する。第二窒素精留塔４は、精留部４２、頂部４３を備える。
第二製品窒素ガスラインＬ４３は、第二窒素精留塔４の頂部４３から導出される第二窒素ガス（蒸気流）を、サブクーラ６を通過した後で、主熱交換器１の冷端へ導入し、温端から導出して、第二製品窒素として取り出すラインである。第一製品窒素ガスの圧力は、第二製品窒素ガスの圧力よりも高圧である。 The second nitrogen rectification column 4 receives the vapor flow from the vapor phase of the first nitrogen condenser section 3 and performs rectification. The second nitrogen rectification column 4 includes a rectification section 42 and a top 43.
The second product nitrogen gas line L43 is a line through which the second nitrogen gas (vapor flow) discharged from the top 43 of the second nitrogen rectification column 4 is introduced into the cold end of the main heat exchanger 1 after passing through the subcooler 6, and discharged from the warm end as second product nitrogen. The pressure of the first product nitrogen gas is higher than the pressure of the second product nitrogen gas.

第二窒素凝縮器５は、頂部４３の上方に設けられる。第二窒素凝縮器５は、第二窒素精留塔４の頂部４３から導出される第二窒素ガス（蒸気流）が、第二凝縮還流ラインＬ４３１を介して導入され、酸素富化液との熱交換によって冷却（凝縮）し液化窒素にする。液化窒素は還流液として第二窒素精留塔４の頂部４３へ戻る。
第一廃ガスラインＬ５３は、第二窒素凝縮器５の気相５３から導出される第二酸素富化ガスを、サブクーラ６へ導入して導出し、冷却された第二酸素富化ガスを、主熱交換器１の冷端へ導入され、温端から廃ガスとして導出するラインである。 The second nitrogen condenser 5 is provided above the top 43. The second nitrogen condenser 5 receives the second nitrogen gas (vapor flow) discharged from the top 43 of the second nitrogen rectification column 4 via the second condensate reflux line L431, and cools (condenses) the second nitrogen gas by heat exchange with the oxygen-enriched liquid to produce liquefied nitrogen. The liquefied nitrogen returns to the top 43 of the second nitrogen rectification column 4 as reflux liquid.
The first waste gas line L53 is a line through which the second oxygen-enriched gas discharged from the gas phase 53 of the second nitrogen condenser 5 is introduced into the subcooler 6 and discharged, and the cooled second oxygen-enriched gas is introduced into the cold end of the main heat exchanger 1 and discharged from the warm end as waste gas.

（実施形態２）
実施形態２の窒素発生装置Ａ２を図２を用いて説明する。実施形態１と同じ符号は、同じ機能を有するので、説明を省略する場合がある。
窒素発生装置Ａ２は、主熱交換器１と、第一窒素精留塔２と、第一窒素凝縮器３と、第二窒素精留塔４と、第二窒素凝縮器５と、サブクーラ６と、第一窒素ブースタータービン７（７１，７２）と、冷却装置８、第二酸素富化ガス膨張タービン９を備える。 (Embodiment 2)
A nitrogen generating device A2 of the second embodiment will be described with reference to Fig. 2. The same reference numerals as those in the first embodiment have the same functions, and therefore the description thereof may be omitted.
The nitrogen generation apparatus A2 includes a main heat exchanger 1, a first nitrogen rectification column 2, a first nitrogen condenser 3, a second nitrogen rectification column 4, a second nitrogen condenser 5, a subcooler 6, a first nitrogen booster turbine 7 (71, 72), a cooling device 8, and a second oxygen-enriched gas expansion turbine 9.

第二廃ガスラインＬ５３１は、第二窒素凝縮器５の気相５３から導出される第二酸素富化ガスを、サブクーラ６へ導入して導出し、冷却された第二酸素富化ガスを主熱交換器１の冷端へ導入し、中間部から導出し、第二酸素富化ガス膨張タービン９へ送り、第二酸素富化ガス膨張タービン９で膨張し冷却し、膨張し冷却した第二酸素富化ガスを、再度、主熱交換器１へ導入し、温端から廃ガスとして導出するラインである。 The second waste gas line L531 is a line that introduces the second oxygen-enriched gas discharged from the gas phase 53 of the second nitrogen condenser 5 to the subcooler 6, introduces the cooled second oxygen-enriched gas to the cold end of the main heat exchanger 1, discharges it from the middle section, sends it to the second oxygen-enriched gas expansion turbine 9, expands and cools it in the second oxygen-enriched gas expansion turbine 9, introduces the expanded and cooled second oxygen-enriched gas back into the main heat exchanger 1, and discharges it from the warm end as waste gas.

（実施形態３）
実施形態３の窒素発生装置Ａ３を図３を用いて説明する。実施形態１、２と同じ符号は、同じ機能を有するので、説明を省略する場合がある。
窒素発生装置Ａ３は、窒素圧縮機７１１、第三冷却装置８１、第一製品窒素第二分岐ラインＬ２３ｂ、第一製品窒素第三分岐ラインＬ２３ｃ、第一窒素ブースター７１、第二窒素ブースター７１ａ、第一冷却装置８ａ、第二冷却装置８ｂ、第一窒素膨張タービン７２と、第二窒素膨張タービン７２ａ、減圧弁１０９、気液分離器１１０を備えている。サブクーラ６は、主熱交換器１とは物理的に別体で構成されている。 (Embodiment 3)
A nitrogen generator A3 according to the third embodiment will be described with reference to Fig. 3. The same reference numerals as those in the first and second embodiments have the same functions, and therefore the description thereof may be omitted.
The nitrogen generation apparatus A3 includes a nitrogen compressor 711, a third cooling apparatus 81, a first product nitrogen second branch line L23b, a first product nitrogen third branch line L23c, a first nitrogen booster 71, a second nitrogen booster 71a, a first cooling apparatus 8a, a second cooling apparatus 8b, a first nitrogen expansion turbine 72, a second nitrogen expansion turbine 72a, a pressure reducing valve 109, and a gas-liquid separator 110. The subcooler 6 is configured as a body physically separate from the main heat exchanger 1.

第一製品窒素分岐ラインＬ２３ａは、窒素圧縮機７１１、第三冷却装置８１、第二窒素ブースター７１ａ、第二冷却装置８ａ、第一窒素ブースター７１、第一冷却装置８を介して、その後に、主熱交換器１の温端から導入し、冷端から導出し、その後に、減圧弁１０９を介して、気液分離器１１０へ導入するためのラインである。
第一製品窒素第二分岐ラインＬ２３ｂは、第二窒素ブースター７１ａより上流の第一製品窒素分岐ラインＬ２３ａから分岐して第一製品窒素ガスの一部を導出し、主熱交換器１の温端から導入し、第一中間部１ａから導出し、第二窒素膨張タービン７２ａで仕事をさせた後で、再び主熱交換器１の中間部へ導入し、主熱交換器１の中で、第二製品窒素ラインＬ４３と合流するためのラインである。
第一製品窒素第三分岐ラインＬ２３ｃは、主熱交換器１の内部の第一製品窒素分岐ラインＬ２３ａから分岐して第一製品窒素ガスの一部を主熱交換器１の第一中間部１ａよりも冷端側の第二中間部１ｂから導出し、第一窒素膨張タービン７２で第一製品窒素ガスを膨張し冷却し、主熱交換器１の冷端より上流の第二製品窒素ラインＬ４３へ合流するためのラインである。 The first product nitrogen branch line L23a is a line for introducing nitrogen through a nitrogen compressor 711, a third cooling device 81, a second nitrogen booster 71a, a second cooling device 8a, a first nitrogen booster 71, and a first cooling device 8, and then from the warm end of the main heat exchanger 1, discharging it from the cold end, and then introducing it into the gas-liquid separator 110 via a pressure reducing valve 109.
The first product nitrogen second branch line L23b branches off from the first product nitrogen branch line L23a upstream of the second nitrogen booster 71a to extract a portion of the first product nitrogen gas, introduce it from the warm end of the main heat exchanger 1, extract it from the first intermediate section 1a, and after doing work in the second nitrogen expansion turbine 72a, introduce it again into the intermediate section of the main heat exchanger 1 and merge with the second product nitrogen line L43 within the main heat exchanger 1.
The first product nitrogen third branch line L23c is a line that branches off from the first product nitrogen branch line L23a inside the main heat exchanger 1 to extract a portion of the first product nitrogen gas from the second intermediate section 1b which is closer to the cold end than the first intermediate section 1a of the main heat exchanger 1, expands and cools the first product nitrogen gas in the first nitrogen expansion turbine 72, and merges with the second product nitrogen line L43 upstream of the cold end of the main heat exchanger 1.

第一窒素ブースター７１と第一窒素膨張タービン７２とで、第一窒素ブースタータービン７を構成し、第二窒素ブースター７１ａと第二窒素膨張タービン７２ａとで、第二窒素ブースタータービン７ａを構成する。
窒素圧縮機７１１は、第一製品窒素分岐ラインＬ２３ａに設けられ、所定圧力に第一製品窒素ガスを昇圧する。第三冷却装置８１は、第一製品窒素分岐ラインＬ２３ａに設けられ、窒素圧縮機７１１で圧縮された第一製品窒素ガスを所定の温度に冷却する。
第二窒素ブースター７１ａは、第一製品窒素分岐ラインＬ２３ａに設けられ、第三冷却装置８１で冷却された第一製品窒素ガスを所定の圧力に昇圧する。第二冷却装置８ａは、第一製品窒素分岐ラインＬ２３ａに設けられ、第二窒素ブースター７１ａで昇圧された第一製品窒素ガスを所定温度へ冷却する。
第一窒素ブースター７１は、第一製品窒素分岐ラインＬ２３ａに設けられ、第二冷却装置８ａで冷却された第一製品窒素ガスを所定の圧力に昇圧する。第一冷却装置８は、第一製品窒素分岐ラインＬ２３ａに設けられ、第一窒素ブースター７１で昇圧された第一製品窒素ガスを所定温度へ冷却する。 The first nitrogen booster 71 and the first nitrogen expansion turbine 72 constitute a first nitrogen booster turbine 7, and the second nitrogen booster 71a and the second nitrogen expansion turbine 72a constitute a second nitrogen booster turbine 7a.
The nitrogen compressor 711 is provided in the first product nitrogen branch line L23a and pressurizes the first product nitrogen gas to a predetermined pressure. The third cooling device 81 is provided in the first product nitrogen branch line L23a and cools the first product nitrogen gas compressed by the nitrogen compressor 711 to a predetermined temperature.
The second nitrogen booster 71a is provided in the first product nitrogen branch line L23a and boosts the first product nitrogen gas cooled in the third cooling device 81 to a predetermined pressure. The second cooling device 8a is provided in the first product nitrogen branch line L23a and cools the first product nitrogen gas boosted in the second nitrogen booster 71a to a predetermined temperature.
The first nitrogen booster 71 is provided in the first product nitrogen branch line L23a and boosts the first product nitrogen gas cooled by the second cooling device 8a to a predetermined pressure. The first cooling device 8 is provided in the first product nitrogen branch line L23a and cools the first product nitrogen gas boosted by the first nitrogen booster 71 to a predetermined temperature.

減圧弁１０９は、主熱交換器１の冷端より下流の第一製品窒素分岐ラインＬ２３ａに設けられ、第一製品窒素ガスを膨張する。減圧弁１０９で、第一製品窒素ガスが膨張され、ガス分と液分の混合状態となり、下流の気液分離器１１０へ送られる。気液分離器１１０は、ガス分と液分とに分離する。ガス分は、第二製品窒素ラインＬ４３へ合流し、主熱交換器１へ再び導入される。液分は、液化窒素として取り出すことができる。 The pressure reducing valve 109 is provided in the first product nitrogen branch line L23a downstream from the cold end of the main heat exchanger 1, and expands the first product nitrogen gas. The first product nitrogen gas is expanded by the pressure reducing valve 109, becoming a mixture of gas and liquid, which is sent to the downstream gas-liquid separator 110. The gas-liquid separator 110 separates the gas and liquid. The gas portion merges with the second product nitrogen line L43 and is introduced again into the main heat exchanger 1. The liquid portion can be extracted as liquefied nitrogen.

第二窒素膨張タービン７２ａは、第二窒素ブースター７１ａより上流の第一製品窒素分岐ラインＬ２３ａから分岐して第一製品窒素ガスの一部を導出し、主熱交換器１の温端から導入し、第一中間部１ａから導出される第一製品窒素ガスを、膨張し冷却する。
第一窒素膨張タービン７２は、第一冷却装置８で冷却され、主熱交換器１の温端から導入し、第一中間部１ａよりも冷端側の第二中間部１ｂから導出される第一製品窒素ガスの一部を、膨張し冷却する。 The second nitrogen expansion turbine 72a branches off from the first product nitrogen branch line L23a upstream of the second nitrogen booster 71a, extracts a portion of the first product nitrogen gas, introduces it from the warm end of the main heat exchanger 1, and expands and cools the first product nitrogen gas extracted from the first intermediate section 1a.
The first nitrogen expansion turbine 72 expands and cools a portion of the first product nitrogen gas that is cooled by the first cooling device 8, introduced from the warm end of the main heat exchanger 1, and discharged from the second intermediate section 1b, which is closer to the cold end than the first intermediate section 1a.

窒素発生装置Ａ３によれば、第一製品窒素ガスの少なくとも一部が、窒素圧縮機７１１で昇圧された後に、第一、第二窒素ブースター７１、７１ａで昇圧され、主熱交換器１で冷却された後に第二窒素ガスの圧力まで減圧され、液化される。この液化窒素流は、多少の気体成分を含むので、減圧弁１０９および気液分離器１１０に導入されて液体と気体に分離される。気体成分は第二窒素ガス流と合流される。
第二窒素ブースター７１ａは、窒素圧縮機７１１から供給される圧縮窒素ガスの一部を主熱交換器１へ導入して第一中間部１ａで導出された後で、第二窒素膨張タービン７２ａにより膨張することによって駆動される。
第一窒素ブースター７１は、第一、第二窒素ブースター７１、７１ａで昇圧された窒素ガスの一部を主熱交換器１へ導入して第二中間部１ｂで導出された後で、第一窒素膨張タービン７２により膨張することによって駆動される。
液化窒素の需要に応えるため、第一窒素ブースタータービン（７１、７２）に追加して、窒素圧縮機７１１と、第二窒素ブースタータービン（７１ａ、７２ａ）を組み合わせた構成である。窒素液化のために、窒素を超臨界圧（例えば５０ｂａｒＡ）まで、窒素圧縮機７１１、第一、第二窒素ブースター７１、７１ａで、圧縮した後に主熱交換器１で冷却し、減圧弁１０９で膨張して液化する。液化に求められる寒冷は、圧縮窒素ガスの一部を第一、第二窒素膨張タービン７２、７２ａで膨張することによって駆動原として使用できる。 According to the nitrogen generator A3, at least a part of the first product nitrogen gas is pressurized by the nitrogen compressor 711, then pressurized by the first and second nitrogen boosters 71, 71a, cooled by the main heat exchanger 1, and then reduced in pressure to the pressure of the second nitrogen gas, and liquefied. Since this liquefied nitrogen stream contains some gas components, it is introduced into the pressure reducing valve 109 and the gas-liquid separator 110 and separated into liquid and gas. The gas components are merged with the second nitrogen gas stream.
The second nitrogen booster 71a is driven by introducing a portion of the compressed nitrogen gas supplied from the nitrogen compressor 711 into the main heat exchanger 1, being discharged through the first intermediate section 1a, and then being expanded by the second nitrogen expansion turbine 72a.
The first nitrogen booster 71 is driven by introducing a portion of the nitrogen gas pressurized in the first and second nitrogen boosters 71, 71a into the main heat exchanger 1, and then being discharged through the second intermediate section 1b, and then being expanded by the first nitrogen expansion turbine 72.
In order to meet the demand for liquefied nitrogen, a nitrogen compressor 711 and a second nitrogen booster turbine (71a, 72a) are combined in addition to the first nitrogen booster turbine (71, 72). For nitrogen liquefaction, nitrogen is compressed to supercritical pressure (e.g., 50 barA) by the nitrogen compressor 711 and the first and second nitrogen boosters 71, 71a, then cooled by the main heat exchanger 1 and expanded by the pressure reducing valve 109 to liquefy. The refrigeration required for liquefaction can be used as a driving source by expanding a portion of the compressed nitrogen gas by the first and second nitrogen expansion turbines 72, 72a.

（実施例）
実施形態１の窒素発生装置の物理シミュレーションの結果を示す。
原料空気が温度２０．０℃、圧力９．９ｂａｒＡ、流量９６２Ｎｍ３／ｈで主熱交換器１の温端から導入され、－１６３．３℃まで冷却されて第一窒素精留塔２に導入される。
第一窒素精留塔２は、頂部２３に第一窒素凝縮器３を備え、頂部２３の窒素ガスを凝縮して第一窒素精留塔２の頂部２３に返す。
その一部の液体窒素５２Ｎｍ３／ｈを導出してサブクーラ６で、－１７９．２℃まで冷却し、第二窒素精留塔４の頂部４３に供給する。第一窒素精留塔２の頂部２３にたまった窒素ガスは、第一製品窒素ガスとして３４６Ｎｍ３／ｈで導出され、主熱交換器１で１９．０℃まで加温され、９．６ｂａｒＡの圧力で導出される。
第一窒素精留塔２の底部２１からは、酸素濃度３５．８％の第一酸素富化液が５６４Ｎｍ３／ｈで導出され、サブクーラ６で－１６８．８℃まで冷却された後に、第二窒素精留塔４の中間に導入される。 (Example)
4 shows the results of a physical simulation of the nitrogen generating apparatus of the first embodiment.
Feed air is introduced from the warm end of the main heat exchanger 1 at a temperature of 20.0° C., a pressure of 9.9 barA and a flow rate of 962 Nm 3 /h, cooled to −163.3° C. and introduced into the first nitrogen rectification column 2 .
The first nitrogen rectification column 2 is equipped with a first nitrogen condenser 3 at its top 23 , and the nitrogen gas at the top 23 is condensed and returned to the top 23 of the first nitrogen rectification column 2 .
A portion of this liquid nitrogen, 52 Nm 3 /h, is discharged and cooled to -179.2°C in subcooler 6 and supplied to top 43 of second nitrogen rectification column 4. Nitrogen gas accumulated in top 23 of first nitrogen rectification column 2 is discharged at 346 Nm 3 /h as first product nitrogen gas, heated to 19.0°C in main heat exchanger 1, and discharged at a pressure of 9.6 barA.
A first oxygen-enriched liquid having an oxygen concentration of 35.8% is discharged from the bottom 21 of the first nitrogen rectification column 2 at a rate of 564 Nm 3 /h, cooled to −168.8° C. in the subcooler 6 , and then introduced into the middle of the second nitrogen rectification column 4 .

第二窒素精留塔４は、頂部４３に第二窒素凝縮器５を備え、頂部４３の窒素ガスを凝縮して第二窒素精留塔４の頂部４３に返す。第二窒素精留塔４の頂部４３にたまった窒素ガスは、第二製品窒素ガスとして３４９Ｎｍ３／ｈで導出され、サブクーラ６を冷却した後、主熱交換器１で１９．０℃まで加温され、４．１ｂａｒＡの圧力で導出される。
第二窒素精留塔４の底部（第一窒素凝縮器３の冷媒貯留部３１）からは、酸素濃度７５．５％の第二酸素富化液が２６７Ｎｍ３／ｈ導出され、サブクーラ６で－１７９．２℃まで冷却された後に、第二窒素凝縮器５の低温側（冷媒貯留部５１）に導入される。第二酸素富化液は、第二窒素凝縮器５で蒸発されて第二酸素富化ガスとなり、サブクーラ６を冷却した後、主熱交換器１で１９．０℃まで加温され、１．２ｂａｒＡの圧力で導出される。
第一製品窒素ガスの内、７０Ｎｍ３／ｈは、第一窒素ブースター７１で１４．６ｂａｒＡまで昇圧され、冷却装置８（アフタークーラ）で３５．０℃まで冷却された後に主熱交換器１の温端から導入され、－７８．４℃まで冷却された後に第一窒素膨張タービン７２で４．２ｂａｒＡまで膨張され、－１２９．６℃まで冷却されて主熱交換器１に導入される。この膨張された窒素ガスは、第二製品窒素ガスと合流して、主熱交換器１から導出される。 The second nitrogen rectification column 4 is equipped with a second nitrogen condenser 5 at its top 43, and the nitrogen gas at the top 43 is condensed and returned to the top 43 of the second nitrogen rectification column 4. The nitrogen gas accumulated at the top 43 of the second nitrogen rectification column 4 is discharged at 349 Nm3 /h as second product nitrogen gas, cooled in the subcooler 6, heated to 19.0°C in the main heat exchanger 1, and discharged at a pressure of 4.1 barA.
A second oxygen-enriched liquid having an oxygen concentration of 75.5% is discharged at 267 Nm3 /h from the bottom of the second nitrogen rectification column 4 (refrigerant reservoir 31 of the first nitrogen condenser 3) and is cooled to -179.2°C in the subcooler 6 before being introduced into the low-temperature side (refrigerant reservoir 51) of the second nitrogen condenser 5. The second oxygen-enriched liquid is evaporated in the second nitrogen condenser 5 to become a second oxygen-enriched gas, which cools the subcooler 6, is heated to 19.0°C in the main heat exchanger 1, and is discharged at a pressure of 1.2 barA.
Of the first nitrogen gas product, 70 Nm3 /h is boosted to 14.6 barA in a first nitrogen booster 71, cooled to 35.0°C in a cooling device 8 (aftercooler), introduced into the warm end of the main heat exchanger 1, cooled to -78.4°C, expanded to 4.2 barA in a first nitrogen expansion turbine 72, cooled to -129.6°C, and introduced into the main heat exchanger 1. This expanded nitrogen gas is combined with the second nitrogen gas product and discharged from the main heat exchanger 1.

第一窒素ブースタータービン７の構成では、第一窒素膨張タービン７１で１．２１ｋＷの寒冷を発生させることができる。従来技術において同等の寒冷を発生させるためには、第一製品窒素ガスを１０９Ｎｍ３／ｈで導出し、－９６．８℃の温度で導出してから膨張させる必要があった。即ち実施例によって寒冷を発生させるために膨張される製品窒素ガス量を３５．８％削減することができた。これにより、その分、窒素圧縮機で再圧縮する動力も削減することができる（窒素圧縮機を削減できる）。 In the configuration of the first nitrogen booster turbine 7, the first nitrogen expansion turbine 71 can generate 1.21 kW of refrigeration. In the prior art, to generate an equivalent amount of refrigeration, it was necessary to output the first product nitrogen gas at 109 Nm 3 /h and expand it after outputting it at a temperature of -96.8°C. In other words, according to the embodiment, the amount of product nitrogen gas expanded to generate refrigeration can be reduced by 35.8%. As a result, the power required for recompression by the nitrogen compressor can also be reduced accordingly (the number of nitrogen compressors can be reduced).

（別実施形態）
（１）特に明示していないが、各配管ラインに圧力調整装置、流量制御装置などが設置され、圧力調整または流量調整が行われていてもよい。
（２）特に明示していないが、各ラインに制御弁、仕切弁などが設置されていてもよい。
（３）特に明示していないが、各塔に圧力調整装置、温度測定装置などが設置され、圧力調整または温度調整が行われていてもよい。
（４）実施形態１、２では、主熱交換器１とサブクーラ６とが連結されている構成であったがこれに制限されず、物理的に分離された別体として構成されていてもよい。
（５）実施形態３では、主熱交換器１とサブクーラ６とが連結されていない構成であったがこれに制限されず、実施形態１、２と同様に連結されていてもよい。 (Another embodiment)
(1) Although not specifically stated, a pressure regulator, a flow rate controller, etc. may be installed in each piping line to adjust the pressure or flow rate.
(2) Although not specifically stated, control valves, gate valves, etc. may be installed on each line.
(3) Although not specifically stated, each tower may be provided with a pressure regulator, a temperature measuring device, etc., for pressure or temperature regulation.
(4) In the first and second embodiments, the main heat exchanger 1 and the subcooler 6 are configured to be connected to each other. However, the present invention is not limited to this. They may be configured as separate entities that are physically separated from each other.
(5) In the third embodiment, the main heat exchanger 1 and the subcooler 6 are not connected to each other. However, the present invention is not limited to this. The main heat exchanger 1 and the subcooler 6 may be connected to each other as in the first and second embodiments.

１ 熱交換器
２ 第一窒素精留塔
３ 第一窒素凝縮器
４ 第二窒素精留塔
５ 第二窒素凝縮器
６ サブクーラ
７１ 第一窒素ブースター
７２ 第一窒素膨張タービン
８ 冷却装置
９ 第二酸素富化ガス膨張タービン Reference Signs List 1 Heat exchanger 2 First nitrogen rectification column 3 First nitrogen condenser 4 Second nitrogen rectification column 5 Second nitrogen condenser 6 Subcooler 71 First nitrogen booster 72 First nitrogen expansion turbine 8 Cooling device 9 Second oxygen-enriched gas expansion turbine

Claims (6)

原料空気が原料空気ラインを介して導入される主熱交換器と、前記主熱交換器で熱交換された原料空気が原料空気ラインを介して導入される第一窒素精留塔と、前記第一窒素精留塔から導出される第一窒素ガスを凝縮し、還流液として前記第一窒素精留塔へ戻す第一窒素凝縮器と、前記第一窒素凝縮器で蒸発された冷媒からなる蒸気流がその底部に導入される第二窒素精留塔と、前記第二窒素精留塔の頂部から導出される第二窒素ガスを凝縮し、還流液として前記第二窒素精留塔へ戻す第二窒素凝縮器と、第一窒素ブースターと、第一窒素膨張タービンと、冷却装置を備える窒素発生装置を用いた窒素製造方法であって、
前記第一窒素精留塔の頂部から導出される第一窒素ガスの一部が、前記主熱交換器へ導入され導出された第一製品窒素ガスの少なくとも一部が、前記第一窒素ブースターで昇圧され、前記冷却装置で冷却された後で、前記主熱交換器の温端から再導入され、前記主熱交換器の中間から導出されて前記第一窒素膨張タービンで膨張して冷却されるステップを含む、窒素製造方法。 A method for producing nitrogen using a nitrogen generating apparatus including a main heat exchanger into which feed air is introduced via a feed air line , a first nitrogen rectification column into which the feed air heat-exchanged in the main heat exchanger is introduced via a feed air line, a first nitrogen condenser which condenses a first nitrogen gas discharged from the first nitrogen rectification column and returns the first nitrogen rectification column as a reflux liquid , a second nitrogen rectification column into the bottom of which a vapor flow consisting of a refrigerant evaporated in the first nitrogen condenser is introduced , a second nitrogen condenser which condenses a second nitrogen gas discharged from the top of the second nitrogen rectification column and returns the second nitrogen rectification column as a reflux liquid , a first nitrogen booster, a first nitrogen expansion turbine, and a cooling device,
a first nitrogen gas discharged from the top of the first nitrogen rectification column is introduced into the main heat exchanger, and at least a portion of the discharged first product nitrogen gas is pressurized in the first nitrogen booster, cooled in the cooling device, and then reintroduced from the warm end of the main heat exchanger, discharged from the middle of the main heat exchanger, and expanded and cooled in the first nitrogen expansion turbine. 前記第二窒素凝縮器の気相から導出される第二酸素富化ガスを、サブクーラを通過させ、前記主熱交換器に導入し、中間部から導出した後で、第二酸素富化ガス膨張タービンで膨張し冷却し、膨張し冷却した第二酸素富化ガスを、前記主熱交換器へ再度導入し、温端から廃ガスとして排出するステップを含む、請求項１に記載の窒素製造方法。 The nitrogen production method according to claim 1, comprising the steps of passing the second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser through a subcooler, introducing it into the main heat exchanger, discharging it from an intermediate section, expanding and cooling it in a second oxygen-enriched gas expansion turbine, and reintroducing the expanded and cooled second oxygen-enriched gas into the main heat exchanger and discharging it from a warm end as waste gas. 原料空気が原料空気ラインを介して導入される主熱交換器と、前記主熱交換器で熱交換された原料空気が原料空気ラインを介して導入される第一窒素精留塔と、前記第一窒素精留塔から導出される第一窒素ガスを凝縮し、還流液として前記第一窒素精留塔へ戻す第一窒素凝縮器と、前記第一窒素凝縮器で蒸発された冷媒からなる蒸気流がその底部に導入される第二窒素精留塔と、前記第二窒素精留塔の頂部から導出される第二窒素ガスを凝縮し、還流液として前記第二窒素精留塔へ戻す第二窒素凝縮器と、第一窒素ブースターと、第一窒素膨張タービンと、冷却装置を備える窒素発生装置であって、
前記第一窒素ブースターは、前記第一窒素精留塔の頂部から導出される第一窒素ガスの一部が、主熱交換器へ導入され、温端から導出された第一製品窒素ガスの少なくとも一部を昇圧し、
前記冷却装置は、前記第一窒素ブースターで昇圧された第一製品窒素ガスを所定の温度へ冷却し、
前記第一窒素膨張タービンは、前記冷却装置で冷却された後で、前記主熱交換器の温端から再導入され、前記主熱交換器の中間から導出された第一製品窒素を膨張して冷却する、窒素発生装置。 A nitrogen generating apparatus comprising: a main heat exchanger into which feed air is introduced via a feed air line ; a first nitrogen rectification column into which the feed air heat-exchanged in the main heat exchanger is introduced via a feed air line ; a first nitrogen condenser which condenses a first nitrogen gas discharged from the first nitrogen rectification column and returns the first nitrogen rectification column as a reflux liquid ; a second nitrogen rectification column into the bottom of which a vapor stream consisting of a refrigerant evaporated in the first nitrogen condenser is introduced ; a second nitrogen condenser which condenses a second nitrogen gas discharged from a top of the second nitrogen rectification column and returns the second nitrogen rectification column as a reflux liquid ; a first nitrogen booster; a first nitrogen expansion turbine; and a cooling device,
The first nitrogen booster is configured to introduce a portion of the first nitrogen gas discharged from the top of the first nitrogen rectification column into a main heat exchanger and to boost the pressure of at least a portion of the first product nitrogen gas discharged from a hot end;
The cooling device cools the first product nitrogen gas pressurized by the first nitrogen booster to a predetermined temperature,
A nitrogen generating apparatus, wherein the first nitrogen expansion turbine expands and cools first product nitrogen that has been cooled by the cooling device and then reintroduced from the warm end of the main heat exchanger and discharged from the middle of the main heat exchanger. 原料空気が原料空気ラインを介して導入される主熱交換器と、
前記主熱交換器で熱交換された原料空気が原料空気ラインを介して導入される第一窒素精留塔と、
前記第一窒素精留塔から導出される第一窒素ガスを凝縮し、還流液として前記第一窒素精留塔へ戻す第一窒素凝縮器と、
前記第一窒素精留塔から導出される第一窒素ガスを、少なくとも前記主熱交換器を介して第一製品窒素として取り出す第一製品窒素ガスラインと、
前記第一製品窒素ガスラインの前記主熱交換器の温端よりも下流側から分岐する第一製品窒素分岐ラインと、
前記第一製品窒素分岐ラインに設けられ、前記第一製品窒素を昇圧する第一窒素ブースターと、
前記第一製品窒素分岐ラインに設けられ、前記第一窒素ブースターで昇圧された第一製品窒素を所定温度へ冷却する冷却装置と、
前記冷却装置で冷却された前記第一製品窒素ガスを、前記主熱交換器の温端から導入し、中間部から導出し、膨張し冷却する第一窒素膨張タービンと、
前記第一窒素凝縮器で蒸発された冷媒からなる蒸気流がその底部に導入される第二窒素精留塔と、
前記第二窒素精留塔の頂部から導出される第二窒素ガスを凝縮し、還流液として前記第二窒素精留塔へ戻す第二窒素凝縮器と、
前記第二窒素精留塔から導出される第二窒素ガスを、少なくとも前記主熱交換器の冷端へ導入し、温端から導出して、第二製品窒素として取り出す第二製品窒素ガスラインと、を備える、窒素発生装置。 a main heat exchanger into which feed air is introduced via a feed air line;
a first nitrogen rectification column into which the feed air that has been heat exchanged in the main heat exchanger is introduced via a feed air line;
a first nitrogen condenser for condensing the first nitrogen gas discharged from the first nitrogen rectification column and returning the condensed first nitrogen gas to the first nitrogen rectification column as a reflux liquid;
a first product nitrogen gas line for extracting the first nitrogen gas discharged from the first nitrogen rectification column as first product nitrogen through at least the main heat exchanger;
a first product nitrogen branch line branching off from the first product nitrogen gas line downstream of the warm end of the main heat exchanger;
a first nitrogen booster provided in the first product nitrogen branch line and configured to boost the pressure of the first product nitrogen;
a cooling device provided in the first product nitrogen branch line and configured to cool the first product nitrogen pressurized by the first nitrogen booster to a predetermined temperature;
a first nitrogen expansion turbine which introduces the first product nitrogen gas cooled by the cooling device from a warm end of the main heat exchanger, discharges the first product nitrogen gas from an intermediate portion, and expands and cools the first product nitrogen gas;
a second nitrogen rectification column into whose bottom a vapor stream consisting of the refrigerant evaporated in the first nitrogen condenser is introduced ;
a second nitrogen condenser for condensing the second nitrogen gas discharged from the top of the second nitrogen rectification column and returning the second nitrogen gas to the second nitrogen rectification column as a reflux liquid;
a second product nitrogen gas line through which the second nitrogen gas discharged from the second nitrogen rectification column is introduced at least into the cold end of the main heat exchanger, discharged from the warm end, and taken out as second product nitrogen. 前記主熱交換器と連結される、あるいは主熱交換器とは別体のサブクーラと、
前記第一窒素精留塔から導出される第一酸素富化液を、前記サブクーラを介して、前記第二窒素精留塔へ導入する第一酸素富化液ラインと、
前記第一窒素凝縮器で凝縮された第一液化窒素を、前記サブクーラを介して、前記第二窒素精留塔へ導入する第一液化窒素ラインと、
前記第一窒素凝縮器の冷媒貯留部から導出される第二酸素富化液を、前記サブクーラを介して、前記第二窒素凝縮器の冷媒貯留部へ導入する第二酸素富化液ラインと、
前記第二窒素凝縮器の気相から導出される第二酸素富化ガスを、前記サブクーラを介して冷却された第二酸素富化ガスを、前記主熱交換器を介して廃ガスとして導出する第一廃ガスラインと、を備える、請求項４に記載の窒素発生装置。 a subcooler coupled to the main heat exchanger or separate from the main heat exchanger;
A first oxygen-enriched liquid line for introducing a first oxygen-enriched liquid discharged from the first nitrogen rectification column into the second nitrogen rectification column via the subcooler;
a first liquefied nitrogen line for introducing the first liquefied nitrogen condensed in the first nitrogen condenser into the second nitrogen rectification column via the subcooler;
A second oxygen-enriched liquid line that introduces the second oxygen-enriched liquid discharged from the refrigerant reservoir of the first nitrogen condenser into the refrigerant reservoir of the second nitrogen condenser via the subcooler;
a first waste gas line for discharging the second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser and cooled via the subcooler as a waste gas via the main heat exchanger. 前記主熱交換器と連結される、あるいは主熱交換器とは別体のサブクーラと、
前記第一窒素精留塔から導出される第一酸素富化液を、前記サブクーラを介して、前記第二窒素精留塔へ導入する第一酸素富化液ラインと、
前記第一窒素凝縮器で凝縮された第一液化窒素を、前記サブクーラを介して、前記第二窒素精留塔へ導入する第一液化窒素ラインと、
前記第一窒素凝縮器の冷媒貯留部から導出される第二酸素富化液を、前記サブクーラを介して、前記第二窒素凝縮器の冷媒貯留部へ導入する第二酸素富化液ラインと、
前記第二窒素凝縮器の気相から導出される第二酸素富化ガスを、前記サブクーラを通過させ、前記主熱交換器に導入し、中間部から導出した後で、第二酸素富化ガス膨張タービンで膨張し冷却し、膨張し冷却した第二酸素富化ガスを、前記主熱交換器へ再度導入し、温端から廃ガスとして排出する第二廃ガスラインを備える、請求項４に記載の窒素発生装置。


 a subcooler coupled to the main heat exchanger or separate from the main heat exchanger;
A first oxygen-enriched liquid line for introducing a first oxygen-enriched liquid discharged from the first nitrogen rectification column into the second nitrogen rectification column via the subcooler;
a first liquefied nitrogen line for introducing the first liquefied nitrogen condensed in the first nitrogen condenser into the second nitrogen rectification column via the subcooler;
A second oxygen-enriched liquid line that introduces the second oxygen-enriched liquid discharged from the refrigerant reservoir of the first nitrogen condenser into the refrigerant reservoir of the second nitrogen condenser via the subcooler;
5. The nitrogen generation apparatus according to claim 4, further comprising a second waste gas line through which the second oxygen-enriched gas discharged from the gas phase of the second nitrogen condenser is passed through the subcooler, introduced into the main heat exchanger, discharged from an intermediate section, and then expanded and cooled in a second oxygen-enriched gas expansion turbine, and the expanded and cooled second oxygen-enriched gas is reintroduced into the main heat exchanger and discharged from a warm end as waste gas.
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