JPH05240579A - Nitrogen producing device - Google Patents
Nitrogen producing deviceInfo
- Publication number
- JPH05240579A JPH05240579A JP4043787A JP4378792A JPH05240579A JP H05240579 A JPH05240579 A JP H05240579A JP 4043787 A JP4043787 A JP 4043787A JP 4378792 A JP4378792 A JP 4378792A JP H05240579 A JPH05240579 A JP H05240579A
- Authority
- JP
- Japan
- Prior art keywords
- oxygen
- gas
- rectification section
- pressure rectification
- rich
- 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.)
- Granted
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 8
- 239000001301 oxygen Substances 0.000 claims abstract description 86
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 86
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 78
- 239000007789 gas Substances 0.000 claims abstract description 50
- 239000007788 liquid Substances 0.000 claims abstract description 44
- 229910001873 dinitrogen Inorganic materials 0.000 claims abstract description 23
- 238000010992 reflux Methods 0.000 claims abstract description 13
- 239000002994 raw material Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 10
- 230000008016 vaporization Effects 0.000 claims 1
- 238000001816 cooling Methods 0.000 abstract description 9
- 230000006835 compression Effects 0.000 abstract description 3
- 238000007906 compression Methods 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract 1
- 239000002912 waste gas Substances 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 239000002808 molecular sieve Substances 0.000 description 5
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 5
- 238000005255 carburizing Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000005194 fractionation Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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
- F25J3/04406—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
- F25J3/0443—A main column system not otherwise provided, e.g. a modified double column flowsheet
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
- F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
- F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04151—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
- F25J3/04254—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using the cold stored in external cryogenic fluids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—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
-
- 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
- F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)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
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/04—Mixing or blending of fluids with the feed stream
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/42—Nitrogen
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
- F25J2230/52—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being oxygen enriched compared to air, e.g. "crude 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
- F25J2245/00—Processes or apparatus involving steps for recycling of process streams
- F25J2245/02—Recycle of a stream in general, e.g. a by-pass stream
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、圧縮空気を原料とし
て、精留塔内での精留により製品窒素ガスを製造する方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing product nitrogen gas by rectification in a rectification column using compressed air as a raw material.
【0002】[0002]
【従来の技術】この種の精留塔による窒素ガス製造方法
としては、単式精留塔の塔頂から取り出された窒素ガス
を主熱交換器の寒冷源として使用した後、常温まで加温
された窒素ガスを、原料空気とほぼ同圧の製品窒素ガス
として得る方法が知られている(例えば特公昭54−3
9830号公報)。2. Description of the Related Art As a method for producing nitrogen gas using a rectification tower of this type, nitrogen gas taken out from the top of a single-column rectification tower is used as a cold source for a main heat exchanger and then heated to room temperature. A known method is to obtain such nitrogen gas as product nitrogen gas having almost the same pressure as that of the raw material air (for example, Japanese Patent Publication No. 54-3).
9830).
【0003】このような従来方法においては、主熱交換
器で液化温度付近まで冷却された原料圧縮空気は、頂部
に凝縮器を備えた単式精留塔の下部に導入され、この精
留塔内での精留により、空気より酸素に富む液体空気
(以下、酸素リッチ液体という。)を塔底に、製品であ
る高純度窒素ガスを塔頂に分離する。In such a conventional method, the raw material compressed air cooled to near the liquefaction temperature in the main heat exchanger is introduced into the lower part of the single-column rectification column equipped with a condenser at the top, and inside the rectification column. As a result of the rectification, liquid air (hereinafter referred to as oxygen-rich liquid) richer in oxygen than air is separated at the bottom of the column, and high-purity nitrogen gas as a product is separated at the top of the column.
【0004】塔底の液溜め部に溜められた酸素リッチ液
体は、管路によって取り出され、膨張された後に塔頂部
の凝縮器に寒冷源として導入され、精留塔を上昇して凝
縮器の凝縮管内に到着した窒素ガスの一部を液化して還
流液とする。この熱交換によって酸素リッチ液体は気化
されて低温の酸素リッチガスとなって取り出され、主熱
交換器において圧縮原料空気を冷却した後、常温の廃ガ
スとして大気中に放出されていた。The oxygen-rich liquid stored in the liquid storage section at the bottom of the column is taken out by a pipe line, expanded, and then introduced into the condenser at the top of the column as a cold source, and then rises in the rectification column to move to the condenser. Part of the nitrogen gas arriving in the condensing pipe is liquefied to form a reflux liquid. Due to this heat exchange, the oxygen-rich liquid is vaporized to be taken out as a low-temperature oxygen-rich gas, and after cooling the compressed raw material air in the main heat exchanger, it is discharged into the atmosphere as a waste gas at room temperature.
【0005】そこで本出願人は、大気中に廃棄されてい
た酸素リッチガスをさらに有効に利用するために、常温
まで加温された酸素リッチガスの少くとも一部を圧縮し
た後に原料圧縮空気と合流させて、主熱交換器に送入し
て冷却した後、精留塔の底部に導入するとともに、全低
温工程中のいずれかにおいて寒冷を別途に補給する窒素
ガス製造方法を先に提案した(特願平2−316289
号)。しかしながらこの方法では、酸素リッチガス(酸
素含有量40〜50%程度)をリサイクルガスとして圧
縮しなければならないので、酸素仕様の圧縮機を必要と
し、その価格が高価であるという問題点があった。Therefore, in order to make more effective use of the oxygen-rich gas discarded in the atmosphere, the present applicant compresses at least a part of the oxygen-rich gas warmed to room temperature and then combines it with the raw material compressed air. First, we proposed a nitrogen gas production method, in which it is introduced into the bottom of the rectification column after being sent to the main heat exchanger for cooling, and cold is separately supplied during any of the low temperature steps ( Wishhei 2-316289
issue). However, in this method, an oxygen-rich gas (oxygen content of about 40 to 50%) has to be compressed as a recycled gas, so that there is a problem that a compressor with an oxygen specification is required and its price is expensive.
【0006】[0006]
【発明が解決しようとする課題】本発明は、上記の問題
点を解決するためリサイクルガス用に酸素仕様の高価な
圧縮機を使用することなく、通常の空気圧縮機を使用で
き、したがって設備費を低減することのできる窒素ガス
製造方法を提供することを目的としている。SUMMARY OF THE INVENTION In order to solve the above problems, the present invention can use a normal air compressor without using an expensive oxygen specification compressor for recycled gas, and therefore the equipment cost can be reduced. It is an object of the present invention to provide a method for producing nitrogen gas that can reduce
【0007】[0007]
【課題を解決するための手段】このため本発明の方法
は、液化温度付近まで冷却された原料圧縮空気を精留塔
の中圧精留部の下方に供給し、前記中圧精留部において
精留分離して中圧精留部の上方から製品窒素ガス、中圧
精留部の下方から酸素リッチ液体を取出す工程と、前記
取出した酸素リッチ液体を膨張後、低圧精留部の上方に
還流液として供給し精留しつつ流下させる工程と、前記
低圧精留部における精留によりさらに濃縮された酸素リ
ッチ液体を凝縮器の寒冷源として中圧精留部から送られ
る窒素ガスを液化させて中圧精留部に還流液として送る
とともに自らは気化されて濃縮酸素リッチガスとなる工
程と、前記濃縮酸素リッチガスを取出してその一部を低
圧精留部の下方に戻す工程と、前記濃縮酸素リッチガス
を低圧精留部において精留分離して低圧精留部の上方よ
り空気と同じ又は空気より酸素含有量の少い混合ガスと
して取出す工程を有することを特徴としている。Therefore, according to the method of the present invention, the raw material compressed air cooled to near the liquefaction temperature is supplied below the middle pressure rectification section of the rectification column, and in the middle pressure rectification section. Rectifying and separating product nitrogen gas from above the medium-pressure rectification section, and oxygen-rich liquid from below the medium-pressure rectification section, and after expanding the extracted oxygen-rich liquid, above the low-pressure rectification section. Supplying as a reflux liquid and flowing down while rectifying, and oxygen-rich liquid further concentrated by rectification in the low-pressure rectification section is used as a cold source of a condenser to liquefy nitrogen gas sent from the intermediate-pressure rectification section. And sent to the medium-pressure rectification section as a reflux liquid to vaporize itself into a concentrated oxygen-rich gas; a step of extracting the concentrated oxygen-rich gas and returning a part of the concentrated oxygen-rich gas to the lower part of the low-pressure rectification section; Rich gas in the low pressure rectification section And rectification separation is characterized by having a step of taking out a small mixed gas oxygen content than the same or air and the air from above the lower pressure rectification unit.
【0008】[0008]
【発明の作用】このような本発明の方法においては、窒
素製造方法であるにもかかわらず中圧精留部のほかに低
圧精留部を設け、膨張後の酸素リッチ液体をこの低圧精
留部で精留して、この酸素リッチ液体より低酸素濃度の
混合ガスを低圧精留部の上方に、酸素リッチ液体よりそ
の分だけさらに濃縮された酸素リッチ液体を低圧精留部
の下方に分離し、濃縮酸素リッチ液体は凝縮器の寒冷源
として使用された後に濃縮酸素リッチガスとして取出す
ことができる。In the method of the present invention as described above, a low pressure rectification section is provided in addition to the medium pressure rectification section in spite of the nitrogen production method, and the oxygen-rich liquid after expansion is subjected to this low pressure rectification. Fractionation is performed in the lower part to separate the mixed gas having a lower oxygen concentration than the oxygen-rich liquid above the low-pressure rectification part, and the oxygen-rich liquid further concentrated to that extent than the oxygen-rich liquid below the low-pressure rectification part. However, the concentrated oxygen-rich liquid can be taken out as concentrated oxygen-rich gas after being used as a cold source for the condenser.
【0009】すなわち従来の技術では、単式精留塔の底
部から取出されて膨張された酸素リッチ液体はそのまま
凝縮器の寒冷源として用いられ、自らは気化されて酸素
リッチガスとして排出されていたのが、低圧精留部を設
けることによって、従来の酸素リッチ液体よりさらに濃
縮された濃縮酸素リッチガスと酸素含有量のさらに少い
低酸素混合ガスの2種類のガスとして取出すことができ
るようになった。That is, in the prior art, the oxygen-rich liquid taken out from the bottom of the single-column rectification column and expanded was used as it is as a cold source for the condenser, and was itself vaporized and discharged as oxygen-rich gas. By providing the low-pressure rectification section, it has become possible to extract two types of gas, a concentrated oxygen-rich gas that is more concentrated than the conventional oxygen-rich liquid and a low-oxygen mixed gas that has a smaller oxygen content.
【0010】低圧精留部を構成する精留板の枚数は、精
留によって低圧精留部の上方空間に空気とほぼ同一か、
あるいは空気よりも酸素含有量の少い低酸素空気が製出
されるように定めればよい。以下、本発明の方法の二つ
の実施態様を例として示す図面に基いて説明する。Is the number of rectification plates constituting the low pressure rectification section substantially the same as air in the space above the low pressure rectification section due to rectification?
Alternatively, it may be determined so that low-oxygen air whose oxygen content is smaller than that of air is produced. Hereinafter, two embodiments of the method of the present invention will be described with reference to the drawings.
【0011】[0011]
【実施例】図1に示されたように、フィルタ(図示せ
ず)で除塵された原料空気GAは、空気圧縮機1におい
て、製品窒素ガス圧力で空気分離装置の運転に必要な圧
力(例えば9.5kg/cm2 G)まで圧縮された後、
管路P1を通って冷却・乾燥・除炭ユニット2に供給さ
れる。この冷却・乾燥・除炭ユニットでは切り替え使用
される2本のモレキュラーシーブ塔からなり、1本のモ
レキュラーシーブ塔では、供給された圧縮原料空気GA
中の水分、二酸化炭素の吸着除去が行われ、もう1本の
モレキュラーシーブ塔では、後述する主熱交換器3で加
温された濃縮酸素リッチ廃ガスGWによるモレキュラー
シーブの再生が行われる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, raw air GA, which has been dust-removed by a filter (not shown), is a product nitrogen gas pressure in an air compressor 1 and the pressure required for operating an air separation device (for example, After being compressed to 9.5 kg / cm 2 G),
It is supplied to the cooling / drying / carburizing unit 2 through the pipeline P1. This cooling / drying / carburizing unit consists of two molecular sieve towers that are switched and used. In one molecular sieve tower, the compressed compressed air GA supplied is supplied.
Moisture and carbon dioxide in the inside are adsorbed and removed, and in the other molecular sieve tower, the molecular sieve is regenerated by the concentrated oxygen-rich waste gas GW heated in the main heat exchanger 3 described later.
【0012】こうして精製された圧縮原料空気GAは、
管路P2を経て主熱交換器3に送られ、ここで後記する
低温の窒素ガスGN及び濃縮酸素リッチ廃ガスGWとの
熱交換によって液化温度付近まで冷却された後、管路P
3を通って精留塔4の下部に供給される。一方、この精
留塔4の上部には、別途に補給される寒冷として液体窒
素LNが管路P4から供給され、精留塔4の還流液の一
部を構成する。還流液は精留塔4の中圧精留部A内を下
降し、精留塔4下部の液溜め部で気化されて中圧精留部
A内を上昇する酸素リッチガスと向流接触し、酸素リッ
チガス中の酸素を液化して還流液中に取り込み、自らは
気化して酸素リッチガスの未液化部分(窒素ガスに富む
ガス)とともに塔内を上昇し、このようにして精留が行
われる。The compressed raw material air GA thus purified is
After being sent to the main heat exchanger 3 via the pipe P2 and being cooled to near the liquefaction temperature by heat exchange with the low-temperature nitrogen gas GN and the concentrated oxygen-rich waste gas GW described later, the pipe P
It is supplied to the lower portion of the rectification column 4 through 3. On the other hand, liquid nitrogen LN is supplied to the upper part of the rectification tower 4 as a cold supplied separately from the pipe line P4 and constitutes a part of the reflux liquid of the rectification tower 4. The reflux liquid descends in the medium-pressure rectification section A of the rectification tower 4, and is countercurrently contacted with the oxygen-rich gas which is vaporized in the liquid storage section at the lower part of the rectification tower 4 and rises in the intermediate-pressure rectification section A. Oxygen in the oxygen-rich gas is liquefied and taken into the reflux liquid, and is vaporized by itself and rises in the column together with the unliquefied part of the oxygen-rich gas (gas rich in nitrogen gas), and thus rectification is performed.
【0013】中圧精留部A内を上昇するガスは、こうし
て窒素含有量を順次多くし、最後に精留塔4上部に設け
られた凝縮器7に送られる。本発明の方法では凝縮器7
の上方に低圧精留部Bが設けられ、凝縮器7に送られた
純度の高い窒素ガスは、低圧精留部Bの上方8に還流液
として供給される後記の低温酸素リッチ液体LWによっ
て最終冷却を受けて液化し、中圧精留部A内に還流液と
して戻される。製品としての高純度窒素ガスGNは、前
記還流液が戻された位置のわずかに下方に開口する管路
P5によって取出され、主熱交換器3にその寒冷源とし
て送られ、ここで前記のように圧縮原料空気GAを冷却
し、自らは常温まで加温されて、例えば9.0kg/c
m2 Gの製品窒素ガスとして管路P7から取り出され
る。The gas rising in the medium-pressure rectification section A thus gradually increases the nitrogen content, and is finally sent to the condenser 7 provided at the upper part of the rectification column 4. In the method of the present invention, the condenser 7
A low-pressure rectification section B is provided above, and the high-purity nitrogen gas sent to the condenser 7 is supplied to the upper part 8 of the low-pressure rectification section B as a reflux liquid by a low-temperature oxygen-rich liquid LW described later. It is cooled, liquefied, and returned to the medium-pressure rectification section A as a reflux liquid. The high-purity nitrogen gas GN as a product is taken out by a pipe line P5 that opens slightly below the position where the reflux liquid is returned, and is sent to the main heat exchanger 3 as its cold source, where it is as described above. The compressed raw material air GA is cooled to, and is warmed to room temperature, for example, 9.0 kg / c
It is taken out from the pipe P7 as m 2 G product nitrogen gas.
【0014】精留部Aでの精留により分離され、精留塔
4底部の液溜め部に溜められた酸素リッチ液体LWは管
路P6によって取り出され、膨張弁5によって例えば
3.5kg/cm2 Gまで膨張後、前記のように低圧精
留部Bの上方8に送られ、低圧精留部Bで精留されつつ
流下し、凝縮器7の寒冷源として利用され自らは気化さ
れる。前記の気化ガスはこの低圧精留部Bによって精留
され、低圧精留部Bの上方8には空気とほぼ同じ組成又
はさらに酸素含有量の少い混合ガスGMが、下方6には
さらに酸素が濃縮された酸素リッチ廃ガスGWが分離さ
れる。この濃縮酸素リッチ廃ガスGWは、管路P8によ
って低圧精留部Bの下方6から取り出されて主熱交換器
3に送られ、前記窒素ガスGNとともに原料圧縮空気G
Aを冷却し、自らは常温まで加温されて少くともその一
部は冷却・乾燥・除炭ユニット2のモレキュラーシーブ
の再生に使用され、管路P9から排出される。The oxygen-rich liquid LW separated by the rectification in the rectification section A and stored in the liquid storage section at the bottom of the rectification column 4 is taken out by a pipe line P6 and is expanded by the expansion valve 5 to, for example, 3.5 kg / cm. After expanding to 2 G, it is sent to the upper part 8 of the low pressure rectification section B as described above, flows down while being rectified in the low pressure rectification section B, is used as a cold source of the condenser 7, and is itself vaporized. The vaporized gas is rectified by the low pressure rectification section B, and a mixed gas GM having almost the same composition as that of air or a lower oxygen content is provided in the upper part 8 of the low pressure rectification section B, and further oxygen is provided in the lower part 6. The oxygen-rich waste gas GW in which the oxygen is concentrated is separated. The concentrated oxygen-rich waste gas GW is taken out from the lower portion 6 of the low pressure rectification section B by a pipe line P8 and sent to the main heat exchanger 3, where it is compressed together with the nitrogen gas GN into the raw material compressed air G.
After cooling A, it is heated to room temperature and at least a part of it is used for regeneration of the molecular sieve of the cooling / drying / carburizing unit 2 and is discharged from the pipe P9.
【0015】低圧精留部Bの上方8に分離された低酸素
混合ガスGMはその頂部から管路P10によって取り出
されて副熱交換器9に送られ、ここで後記の圧縮低酸素
混合ガスGMを冷却し、自らは加温されて副熱交換器9
から管路P11を経て圧縮機10に供給される。混合ガ
スGMは、この圧縮機10によって精留塔4の運転圧
力、例えば9.5kg/cm2 Gまで圧縮されて、管路
P12により前記のように副熱交換器9に送られ、液化
温度近くまで冷却された後、管路P13を経て冷却原料
圧縮空気管路3に合流し、精留塔4の底部に供給され
る。The low oxygen mixed gas GM separated in the upper part 8 of the low pressure rectification section B is taken out from the top of the low pressure rectification section B by a pipe line P10 and sent to a sub heat exchanger 9, where a compressed low oxygen mixed gas GM described later is obtained. And is heated by itself, and the sub heat exchanger 9
Is supplied to the compressor 10 via the pipe line P11. The mixed gas GM is compressed by the compressor 10 to the operating pressure of the rectification column 4, for example, 9.5 kg / cm 2 G, and sent to the sub heat exchanger 9 as described above by the pipe line P12, and the liquefaction temperature is increased. After being cooled to the vicinity, it is joined to the cooling raw material compressed air pipeline 3 via the pipeline P13 and supplied to the bottom of the rectification tower 4.
【0016】このように本発明の方法によれば、従来方
法では少くともその一部をリサイクルガスとして圧縮機
にかけていた酸素リッチガスを、精留塔4の上部に位置
する凝縮器7の上方に複数枚の精留部Bを新たに設けて
精留することによって、空気とほぼ同一又はさらに酸素
含有量の少い低酸素混合ガスGMと、その分だけ酸素に
富んだ濃縮酸素リッチ廃ガスGWとに分離することがで
きるので、圧縮機にかける必要があるリサイクルガスと
しては低酸素混合ガスを用い、濃縮酸素リッチ廃ガスは
圧縮することなく主熱交換器3の寒冷源として用いれ
ば、圧縮機10を酸素仕様の特殊なものとせず、通常の
空気圧縮機とすることが可能となる。As described above, according to the method of the present invention, a plurality of oxygen-rich gases, which have been subjected to the compressor by using at least a part of them as recycled gas in the conventional method, are provided above the condenser 7 located above the rectification column 4. By newly providing a rectification section B of one sheet and rectifying, a low-oxygen mixed gas GM having almost the same oxygen content as that of air or a smaller oxygen content, and a concentrated oxygen-rich waste gas GW rich in oxygen by that amount. Therefore, if a low oxygen mixed gas is used as the recycle gas that needs to be applied to the compressor and the concentrated oxygen rich waste gas is used as a cold source of the main heat exchanger 3 without being compressed, It is possible to use a normal air compressor without making 10 a special oxygen specification.
【0017】次に図2の実施態様を参照すると、低圧精
留部Bの下方6から取り出された濃縮酸素リッチ廃ガス
GWは、図1の場合と同様に管路P8によって主熱交換
器3に寒冷源として供給されるが、この実施態様では、
濃縮酸素リッチ廃ガスGWの少くとも一部は管路P14
によって主熱交換器3の中間から取り出され、膨張ター
ビン11で膨張された後、別途に補給される寒冷として
管路P15を通って再び主熱交換器3に導入される。し
たがって図2の実施態様の場合、図1において示され
た、管路P4から精留塔4上部への液体窒素LNの供給
は不要である。図3の実施態様は図1の実施態様の変形
であり、副熱交換器9に代えて主熱交換器3に、低酸素
混合ガスGM用の通路が設けられている。したがって管
路P10によって低圧精留部Bの上方8から取出された
低酸素混合ガスGMは熱交換器3に送られて、後記の圧
縮低酸素混合ガスGMが合流された原料圧縮空気GAを
冷却し、自らは加温されて管路11によって熱交換器3
を離れ、圧縮機10によって精留塔4の運転圧力まで圧
縮されて、管路12を経て管路P2の圧縮原料空気と合
流し、主熱交換器3に送られる。Next, referring to the embodiment of FIG. 2, the concentrated oxygen-rich waste gas GW taken out from the lower portion 6 of the low-pressure rectification section B is supplied to the main heat exchanger 3 through the pipe line P8 as in the case of FIG. Is supplied as a cold source in this embodiment, in this embodiment,
At least a part of the concentrated oxygen-rich waste gas GW is a pipe line P14.
Is taken out from the middle of the main heat exchanger 3, expanded by the expansion turbine 11, and then introduced into the main heat exchanger 3 again as cold supplied separately through the pipe line P15. Therefore, in the case of the embodiment of FIG. 2, the supply of liquid nitrogen LN from the line P4 to the upper part of the rectification column 4 shown in FIG. 1 is unnecessary. The embodiment of FIG. 3 is a modification of the embodiment of FIG. 1, and instead of the auxiliary heat exchanger 9, the main heat exchanger 3 is provided with a passage for the low oxygen mixed gas GM. Therefore, the low-oxygen mixed gas GM taken out from the upper part 8 of the low-pressure rectification section B by the pipe P10 is sent to the heat exchanger 3 to cool the raw material compressed air GA with which the compressed low-oxygen mixed gas GM described later is joined. However, the heat exchanger 3 is heated by the pipe line 11 by itself.
, And is compressed to the operating pressure of the rectification column 4 by the compressor 10, merges with the compressed feed air in the pipe P2 via the pipe 12, and is sent to the main heat exchanger 3.
【0018】次に図4の実施態様は図2の実施態様の変
形であり、図3の実施態様と同様に副熱交換器9に代え
て主熱交換器3に、低酸素混合ガスGM用の通路を設け
たものである。したがってこの実施態様における低酸素
混合ガスGMの流れは図3の場合と同様なので説明は省
略する。Next, the embodiment shown in FIG. 4 is a modification of the embodiment shown in FIG. 2. As in the embodiment shown in FIG. 3, the main heat exchanger 3 is replaced by the main heat exchanger 3 instead of the auxiliary heat exchanger 9 for the low oxygen mixed gas GM. The passage is provided. Therefore, the flow of the low oxygen mixed gas GM in this embodiment is the same as that in the case of FIG.
【0019】図1ないし図4の実施態様では、中圧精留
部A、低圧精留部B及び凝縮器7は、すべて精留塔4内
に設けられている。しかし製作の便宜上、図5に示すよ
うにこれらを別個に設けて、管路によって接続すること
もできる。In the embodiment of FIGS. 1 to 4, the medium pressure rectification section A, the low pressure rectification section B and the condenser 7 are all provided in the rectification column 4. However, for manufacturing convenience, they may be provided separately and connected by a conduit as shown in FIG.
【0020】図5では、中圧精留部Aの下方から管路P
6で取出された酸素リッチ液体LWは、膨張弁5で膨張
後、低圧精留部Bの上方8に供給され、低圧精留部Bで
の精留により上方8に分離された低酸素混合ガスGMは
管路10か取出され、下方6に分離された濃縮酸素リッ
チ液体は管路P17により凝縮器7に送られ、中圧精留
部Aの上方から管路19を経て凝縮器7に入る窒素ガス
を液化して管路20から中圧精留部Aの還流液として戻
し、自らは気化されて管路8から取出されて一部は主熱
交換器へその寒冷源として送られ、残部は管路18を経
て低圧精留部Bの下方6に戻されて精留にかけられるの
である。In FIG. 5, the conduit P is drawn from below the medium pressure rectification section A.
The oxygen-rich liquid LW taken out in 6 is expanded in the expansion valve 5 and then supplied to the upper part 8 of the low-pressure rectification section B, and the low-oxygen mixed gas separated in the upper part 8 by the rectification in the low-pressure rectification section B. The GM is taken out from the pipe line 10, the concentrated oxygen-rich liquid separated into the lower part 6 is sent to the condenser 7 by the pipe line P17, and enters the condenser 7 from above the intermediate pressure rectification section A via the pipe line 19. The nitrogen gas is liquefied and returned from the pipe 20 as the reflux liquid of the medium-pressure rectification section A, and is vaporized by itself, taken out from the pipe 8 and partly sent to the main heat exchanger as its cold source, and the rest. Is returned to the lower part 6 of the low-pressure rectification section B via a line 18 and subjected to rectification.
【0021】なお図2及び図4においては、酸素リッチ
廃ガスGWの全量を膨張させて主熱交換器3に戻してい
るので、管路P5によって取り出される窒素ガス以外
に、管路P16によて液体窒素LNも取り出すことがで
きる。2 and 4, the whole amount of the oxygen-rich waste gas GW is expanded and returned to the main heat exchanger 3. Therefore, in addition to the nitrogen gas taken out by the line P5, the line P16 is used. Liquid nitrogen LN can also be taken out.
【0022】[0022]
【発明の効果】本発明の方法は前記のような構成を有す
るので、凝縮器空間内で気化された酸素リッチガスを凝
縮器上方の低圧精留部で精留し、空気とほぼ同一又はさ
らに酸素含有量の少い低酸素混合ガスと、その分だけ酸
素が濃縮された酸素リッチ廃ガスとに分離できるので、
圧縮を必要とするリサイクルガスとしては低酸素混合ガ
スを用いることができる。したがってリサイクルガス圧
縮用の圧縮機として通常の空気圧縮機を用いることが可
能となり、従来方法で使用されていた酸素仕様の特殊な
圧縮機に比べて設備費を低減することができる。Since the method of the present invention has the above-mentioned constitution, the oxygen-rich gas vaporized in the condenser space is rectified in the low pressure rectification section above the condenser, and is almost the same as the air or more oxygen. Since it can be separated into a low-oxygen mixed gas with a small content and an oxygen-rich waste gas in which oxygen is concentrated by that amount,
A low-oxygen mixed gas can be used as a recycle gas that requires compression. Therefore, an ordinary air compressor can be used as a compressor for recycle gas compression, and the equipment cost can be reduced as compared with the special compressor of oxygen specification used in the conventional method.
【図1】本発明の一実施態様を示すフローシート。FIG. 1 is a flow sheet showing an embodiment of the present invention.
【図2】本発明の他の実施態様を示すフローシート。FIG. 2 is a flow sheet showing another embodiment of the present invention.
【図3】図1の実施態様の一変形を示すフローシート。FIG. 3 is a flow sheet showing a modification of the embodiment of FIG.
【図4】図2の実施態様の一変形を示すフローシート。FIG. 4 is a flow sheet showing a modification of the embodiment of FIG.
【図5】図1又は図3の精留塔の一変形を示すフローシ
ート。5 is a flow sheet showing a modification of the rectification column of FIG. 1 or FIG.
A、B 精留部 1、10 空気圧縮機 2 冷却・乾燥・除炭ユニット 3 主熱交換器 4 単式精留塔 5 膨張弁 6 精留部Bの下方 7 凝縮器 8 精留部Bの上方 9 副熱交換器 11 膨張タービン P1〜P20 管路 A, B Fractionation section 1, 10 Air compressor 2 Cooling / drying / carburizing unit 3 Main heat exchanger 4 Single-column rectification column 5 Expansion valve 6 Below rectification section B 7 Condenser 8 Above rectification section B 9 Secondary heat exchanger 11 Expansion turbine P1-P20 Pipeline
Claims (1)
気を精留塔の中圧精留部(A)の下方の供給し、前記中
圧精留部(A)において精留分離して中圧精留部(A)
の上方から製品窒素ガス、中圧精留部(A)の下方から
酸素リッチ液体を取出す工程と、前記取出した酸素リッ
チ液体を膨張後、低圧精留部(B)の上方に還流液とし
て供給し精留しつつ流下させる工程と、前記低圧精留部
(B)における精留によりさらに濃縮された酸素リッチ
液体を凝縮器(7)の寒冷源として中圧精留部(A)か
ら送られる窒素ガスを液化させて中圧精留部(A)に還
流液として送るとともに自らは気化されて濃縮酸素リッ
チガスとなる工程と、前記濃縮酸素リッチガスを取出し
てその一部を低圧精留部(B)の下方に戻す工程と、前
記濃縮酸素リッチガスを低圧精留部(B)において精留
分離して低圧精留部(B)の上方(8)より空気と同じ
又は空気より酸素含有量の少い混合ガスとして取出す工
程を有する窒素製造方法。1. A raw material compressed air cooled to around a liquefaction temperature is supplied below a middle pressure rectification section (A) of a rectification column, and is rectified and separated in the intermediate pressure rectification section (A). Pressure rectification section (A)
Of the product nitrogen gas from above, and the oxygen-rich liquid from below the medium-pressure rectification section (A), and after the extracted oxygen-rich liquid is expanded, supplied as reflux liquid above the low-pressure rectification section (B). The oxygen-rich liquid further concentrated by the step of rectifying and flowing down and the rectification in the low-pressure rectification section (B) is sent from the medium-pressure rectification section (A) as a cold source of the condenser (7). A step of liquefying nitrogen gas and sending it to the medium-pressure rectification section (A) as a reflux liquid, and vaporizing itself to become a concentrated oxygen-rich gas; ), And the concentrated oxygen-rich gas is rectified and separated in the low-pressure rectification section (B) to have the same oxygen content as that of air or a lower oxygen content than air from above (8) above the low-pressure rectification section (B). Made of nitrogen that has a process to extract it as a mixed gas Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4043787A JP2810819B2 (en) | 1992-02-28 | 1992-02-28 | Nitrogen production method and apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4043787A JP2810819B2 (en) | 1992-02-28 | 1992-02-28 | Nitrogen production method and apparatus |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH05240579A true JPH05240579A (en) | 1993-09-17 |
JP2810819B2 JP2810819B2 (en) | 1998-10-15 |
Family
ID=12673464
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4043787A Expired - Lifetime JP2810819B2 (en) | 1992-02-28 | 1992-02-28 | Nitrogen production method and apparatus |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2810819B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2819046A1 (en) * | 2001-01-03 | 2002-07-05 | Air Liquide | Cryogenic distillation air separation plant uses compressor to compress nitrogen-rich flow with inlet temperature below that of heat exchanger |
JP2007003097A (en) * | 2005-06-23 | 2007-01-11 | Air Water Inc | Nitrogen generating method and device using the same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62155486A (en) * | 1985-12-27 | 1987-07-10 | 株式会社日立製作所 | Method of separating air |
-
1992
- 1992-02-28 JP JP4043787A patent/JP2810819B2/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62155486A (en) * | 1985-12-27 | 1987-07-10 | 株式会社日立製作所 | Method of separating air |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2819046A1 (en) * | 2001-01-03 | 2002-07-05 | Air Liquide | Cryogenic distillation air separation plant uses compressor to compress nitrogen-rich flow with inlet temperature below that of heat exchanger |
JP2007003097A (en) * | 2005-06-23 | 2007-01-11 | Air Water Inc | Nitrogen generating method and device using the same |
US8549878B2 (en) | 2005-06-23 | 2013-10-08 | Air Water Inc. | Method of generating nitrogen and apparatus for use in the same |
Also Published As
Publication number | Publication date |
---|---|
JP2810819B2 (en) | 1998-10-15 |
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