JPH0427476B2 - - Google Patents
Info
- Publication number
- JPH0427476B2 JPH0427476B2 JP32021390A JP32021390A JPH0427476B2 JP H0427476 B2 JPH0427476 B2 JP H0427476B2 JP 32021390 A JP32021390 A JP 32021390A JP 32021390 A JP32021390 A JP 32021390A JP H0427476 B2 JPH0427476 B2 JP H0427476B2
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen gas
- heat exchanger
- rectification
- tower
- main heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 130
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 68
- 239000007788 liquid Substances 0.000 claims description 37
- 229910052757 nitrogen Inorganic materials 0.000 claims description 31
- 238000004140 cleaning Methods 0.000 claims description 28
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 20
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 238000010992 reflux Methods 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 8
- 239000002994 raw material Substances 0.000 claims description 8
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- 239000001569 carbon dioxide Substances 0.000 claims description 3
- 238000003860 storage Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- 229910001882 dioxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000000356 contaminant Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002808 molecular sieve Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- 239000002912 waste gas Substances 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005057 refrigeration Methods 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000004781 supercooling Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011084 recovery 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
- F25J3/04248—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
- F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04333—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
- F25J3/04351—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 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
- F25J3/044—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 single pressure main column system only
-
- 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
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/42—Nitrogen
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2245/00—Processes or apparatus involving steps for recycling of process streams
- F25J2245/40—Processes or apparatus involving steps for recycling of process streams the recycled stream being air
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2245/00—Processes or apparatus involving steps for recycling of process streams
- F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen
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)
Description
〔産業上の利用分野〕
本発明は、圧縮空気を原料とし、単式精溜塔に
より製品窒素ガスを製造する窒素ガス製造方法に
関する。
〔従来の技術〕
この種の単式精溜塔利用の窒素ガス製造方法と
しては、精溜塔の塔頂から取出した窒素ガスを主
熱交換器の寒冷源として使用したのち、この常温
まで加温された窒素ガスを原料空気とほぼ同圧の
低圧製品窒素ガスとして取出す方法が知られてい
る（例えば、特公昭54−39830号公報）。
〔発明が解決しようとする課題〕
上記の従来方法による場合は、精溜塔の下部か
ら供給される原料空気と精溜塔の上部から下降す
る還流液との接触による分縮作用により、原料空
気から窒素ガスを精溜分離することができるので
あるが、まだ、原料空気量に対する窒素ガスの回
収率は低く、現行の窒素ガス製造設備における収
率を見てみると、下記の表で示すように37％〜48
％程度の収率である。
[Industrial Application Field] The present invention relates to a method for producing nitrogen gas using compressed air as a raw material and producing a product nitrogen gas using a single rectification column. [Prior art] This type of nitrogen gas production method using a single rectification tower involves using the nitrogen gas taken out from the top of the rectification tower as a cooling source for the main heat exchanger, and then heating it to room temperature. A method is known in which the nitrogen gas thus produced is extracted as a low-pressure product nitrogen gas having approximately the same pressure as the raw material air (for example, Japanese Patent Publication No. 54-39830). [Problems to be Solved by the Invention] In the case of the above-mentioned conventional method, the raw air is However, the recovery rate of nitrogen gas relative to the amount of raw air is still low, and if we look at the yield with current nitrogen gas production equipment, it is as shown in the table below. 37% to 48
% yield.
本発明による窒素ガス製造方法は、精溜塔の塔
頂から取出した窒素ガスを過冷却器、主熱交換器
の寒冷源として使用して常温まで加温した後に、
この窒素ガスの少なくとも一部を圧縮した後、主
熱交換器に戻して液化点付近まで冷却し、精溜塔
の底部に設けられた液体窒素洗浄塔の下部に供給
して塔の洗浄部内を上昇させ、洗浄塔頂部に設け
られたコンデンサで精溜塔底部の不純液体酸素に
より冷却液化されて下降する液体窒素と向流状態
で接触させて不純物を洗浄除去した後、洗浄塔の
塔頂から取出し、再び主熱交換器で常温まで加温
して積浄な製品中圧窒素ガスとして取出し、洗浄
塔の底部から取出された液体窒素は前記過冷却器
で過冷却後、膨張させて精溜塔の上部に還流液と
して供給すると共に、全工程中において別途に寒
冷を補給する点に特徴を有し、それによる作用・
効果は次の通りである。
〔作 用〕
精溜塔の塔頂から取出される低圧窒素ガスの寒
冷エネルギーを過冷却器及び主熱交換器での寒冷
源として使用し、窒素ガスを常温にまで加温す
る。この窒素ガスの少なくとも一部を圧縮し、主
熱交換器で冷却した後、精溜塔の底部に設けられ
た液体窒素洗浄塔の下部に供給する。この洗浄塔
内に供給された窒素ガスは上昇して洗浄塔頂部の
コンデンサ内で精溜塔底部の不純液体酸素と熱交
換され、窒素ガスの一部は凝縮して液体窒素とし
て下降する。この液体窒素と洗浄塔の下部に供給
される窒素ガスとが向流状態で接触し、圧縮時に
混入した窒素ガス中のゴミ粒子やその他の汚染物
質が液体窒素にて洗浄除去される。他方、不純液
体酸素は加熱され、この加熱に伴つて蒸発したガ
スは、精溜塔内を下降する液体窒素（還流液）と
向流状態で接触しながら上昇し、酸素は液化して
下降し、窒素に富むガスが上昇して精溜が行われ
る。
前記洗浄塔の頂部から取出される洗浄後の中圧
窒素ガスは主熱交換器での寒冷源として使用され
たのち、清浄な製品中圧窒素ガスとして取出され
る。
又洗浄塔の底部から取出された液体窒素は、過
冷却器で過冷却された後膨張され、原料空気から
窒素成分を精溜分離する上で必要となる還流液と
して精溜塔の上部に供給されるので、窒素ガス収
率の一層の向上に役立つている。
〔発明の効果〕
従つて、精溜塔の塔頂から取出される低圧窒素
ガスを過冷却器及び主熱交換器での寒冷源として
利用した後に圧縮し、かつ、冷却して洗浄塔の下
部からその頂部のコンデンサに供給し、精溜塔底
部の不純液体酸素に対する加熱源として利用する
ことと、洗浄塔の塔頂から取出される中圧窒素ガ
スを主熱交換器での寒冷源としてそれぞれ利用す
ること、並びに、この洗浄塔で液化した液体窒素
を精溜塔での還流液として利用することとの相乗
により、従来の製造方法に比して窒素ガスの収率
向上と単位量当たりの製造コストの低廉化とを図
ることができる。
しかも、洗浄塔内での液体窒素と窒素ガスとの
向流状態での接触により、圧縮時に混入した窒素
ガス中のゴミ粒子やその他の汚染物質を洗浄除去
することができるから、清浄な中圧の製品窒素ガ
スを連続製造することができるのである。
〔実施例〕
先ず、本発明による窒素ガス製造方法を第１図
に基づいて説明する。
空気濾過器（図示せず）で除塵された原料空気
（GA）を圧縮機１で空気分離運転に必要な圧力
（例えば、4.7Kg／cm2Ｇ）まで圧縮した後、この圧
縮原料空気GAを配管Ｐ１を通して冷却・除炭・
乾燥ユニツト２に供給する。この冷却・除炭・乾
燥ユニツト２では、圧縮原料空気GAをアフター
クーラで常温まで冷却したのち、冷凍設備により
約５℃まで冷却し、さらに、二塔よりなるモレキ
ユラーシーブ塔のうちの一方に供給し、原料空気
GA中の炭酸ガス及び水分を吸着除去する。その
間、他方のモレキユラーシーブ塔には後述の主熱
交換器３を通過した廃ガス（不純酸素ガス）を供
給して再生する。
この冷却・除炭・乾燥ユニツト２で炭酸ガス、
水分、その他不純物を除去された原料空気GAを
配管Ｐ２を通して主熱交換器３に供給し、液化点
付近まで冷却した後、配管Ｐ３を通して精溜塔４
下部の原料空気供給部４ａに供給する。又、この
精溜塔４の上部に、寒冷源の一例である液体窒素
LNを配管Ｐ４を通して供給し、精溜塔４内の主
精溜部４ｂにおいて、下部から上昇する原料空気
と精溜塔４内の上部から下降する液体窒素（還流
液）とを向流状態で接触させ、原料空気GAから
酸素を液化させて窒素ガスを精分離する。
前記精溜塔４の塔頂から取出した窒素ガスGN
を配管Ｐ５を通して過冷却器５に、さらに配管Ｐ
６を通して主熱交換器３に供給し、窒素ガスGN
の寒冷エネルギーを過冷却器５及び主熱交換器３
での寒冷源として使用すると共に、窒素ガスGN
を常温にまで加温する。この主熱交換器３から配
管Ｐ２１を通して取出される常温窒素ガスを圧縮
機６に供給し、原料空気GAとぼ同圧の窒素ガス
GN（例えば、4.0Kg／cm2Ｇ）を中圧（例えば、9.0
Kg／cm2Ｇ）にまで圧縮する。
前記圧縮機６から取出される圧縮窒素ガスを配
管Ｐ２２を通して主熱交換器３に戻し、液化点付
近まで冷却した後、配管Ｐ２３を通して精溜塔４
の底部に設けられた液体窒素洗浄塔１２の下部に
供給する。この洗浄塔１２内に供給された窒素ガ
スGNは、洗浄部１２ａを上昇して、洗浄塔１２
の頂部の、精溜塔４底部の不純液体酸素溜部４ｃ
内に位置する状態で設けられたコンデンサ１２ｂ
で不純液体酸素Ｌ０と熱交換され、窒素ガスGN
の一部は凝縮して液体窒素LNとして下降する。
この液体窒素LNと洗浄塔１２の下部部に供給さ
れる窒素ガスGNとが洗浄部１２ａにおいて向流
状態で接触し、圧縮時に混入した窒素ガスGN中
のゴミ粒子やその他の汚染物質が液体窒素LNに
て洗浄除去される。
他方、不純液体酸素Ｌ０は加熱され、この加熱
に伴つて蒸発したガスは、精溜塔４の、原料空気
供給部４ａと不純液体酸素溜部４ｃとの間に介在
された補助精溜部４ｄを通して精溜塔４の上部に
上昇し、精溜塔内を下降する液体窒素（還流液）
と向流状態で接触して、酸素は液化して下降し、
窒素に富むガスが上昇して精溜が行われる。この
ような補助精溜部４ｄ及び主精溜部４ｂでの２段
精溜分離作用により、窒素ガスの率を向上するこ
とができる。
前記洗浄塔１２頂部から配管Ｐ２４を通して取
出される洗浄後の中圧窒素ガスGNを主熱交換器
３に供給し、この中圧窒素ガスGNの寒冷エネル
ギーーを主熱交換器３での寒冷源として使用する
と共に、中圧窒素ガスGNを常温にまで加温した
後、この主熱交換器３から配管Ｐ２５を通して清
浄な製品中圧窒素ガスを取出す。
又、洗浄塔１２の底部から配管Ｐ１２を通して
取出された液体窒素LNを過冷却器５に供給し、
液体窒素LNを過冷却した後、膨張弁８を有する
配管Ｐ１３に導き、膨張させて精溜塔４の上部に
還流液として供給する。
前記精溜塔４の不純体酸素溜部４ｃの下部から
取出された不純液体酸素Ｌ０を配管Ｐ１４を通し
て過冷却器５に供給し、不純液体酸素Ｌ０を過冷
却した後、膨張弁９を有する配管Ｐ１５に導き、
膨張させて精溜塔４の上部に設けられたコンデン
サ１０に供給する。このコンデンサ１０内で減圧
蒸発される不純液体酸素Ｌ０と精溜塔４内の上部
に存在する低温窒素ガスGNとが熱交換され、低
温窒素ガスGNの一部が液化されて還流液として
下降する。
前記コンデンサ１０で蒸発した不純酸素ガスＧ
０を配管Ｐ１６を通して過冷却器５に、さらに、
配管Ｐ１７を通して主熱交換器３に供給し、不純
酸素ガスＧ０の寒冷エネルギーを過冷却器５及び
主熱交換器３での寒冷源として使用する。この寒
冷放出に伴つて常温まで加温された不純酸素ガス
の廃ガスＧ０は、配管Ｐ１８を通して冷却・除
炭・乾燥ユニツト２の非使用のモレキユラーシー
ブ塔に供給され、再生ガスとして使用された後、
外部に放出される。
尚、上述の実施例では、前記主熱交換器３で最
初に常温まで加温された窒素ガスGNの全てを圧
縮して主熱交換器３に戻し、清浄な中圧窒素ガス
のみを製品として取出したが、この製造方法に限
定されるものではなく、例えば、主熱交換器３で
最初に常温まで加温された窒素ガスGNの一部を
原料空気GAとほぼ同圧の低圧製品窒素ガスとし
て取出し、残部を圧縮して主熱交換器３へ戻し、
清浄な中圧製品窒素ガスとして取出すようにして
もよい。
又、上述の実施例では、全工程中において別途
に寒冷を補給する方法として、外部から精溜塔４
の上部に液体窒素LNを供給したが、この補給方
法に限定されるものではなく、例えば、第２図に
示すように、前記主熱交換器３の、原料空気供給
系の中間から配管Ｐ１９を通して取出された一部
の原料空気GAを膨張タービン１１で断熱膨張し
た後、この膨張タービン１１から配管Ｐ２０を通
して取出される寒冷の原料空気を過冷却器５を通
過した廃ガス（不純酸素ガス）系の配管Ｐ１７に
合流させ、もつて、この原料空気GAの一部を主
熱交換器３の寒冷源として補給してもよい。
更に、上述の各実施例では、原料空気を圧縮す
る圧縮機１と、主熱交換器３で最初に常温まで加
温された窒素ガスを圧縮する圧縮機６との二つの
圧縮機を使用した製造方法について説明したが、
これに限定されるものではない。つまり、これら
二つの圧縮機１，６の圧力レベルを考慮すると、
同一の圧縮機の低圧段を原料空気圧縮用に、そし
て又高圧段を窒素ガス圧縮用にそれぞれ使用する
ことにより、一つの圧縮機を用いて兼用すること
もできる。
尚、特許請求の範囲の項に図面との対照を便利
にする為に符号を記すが、該記入により本発明は
添付図面の構成に限定されるものではない。
In the nitrogen gas production method according to the present invention, nitrogen gas taken out from the top of a rectification column is used as a cold source for a supercooler and a main heat exchanger to warm it to room temperature, and then
After compressing at least a portion of this nitrogen gas, it is returned to the main heat exchanger and cooled to near the liquefaction point, and then supplied to the lower part of the liquid nitrogen cleaning tower installed at the bottom of the rectification tower to clean the inside of the cleaning section of the tower. The liquid nitrogen is cooled and liquefied by impure liquid oxygen at the bottom of the rectification tower in a condenser installed at the top of the cleaning tower, and is brought into contact with the descending liquid nitrogen in a countercurrent state to wash and remove impurities, and then from the top of the cleaning tower. The liquid nitrogen taken out from the bottom of the cleaning tower is subcooled in the supercooler, then expanded and purified. It is characterized by the fact that it is supplied as a reflux liquid to the upper part of the tower, and that refrigeration is supplied separately during the entire process, and the effects and
The effects are as follows. [Operation] The cold energy of the low-pressure nitrogen gas taken out from the top of the rectification tower is used as a cold source in the supercooler and main heat exchanger to warm the nitrogen gas to room temperature. At least a portion of this nitrogen gas is compressed, cooled in a main heat exchanger, and then supplied to the lower part of a liquid nitrogen cleaning tower provided at the bottom of the rectification tower. The nitrogen gas supplied into the cleaning tower rises and exchanges heat with impure liquid oxygen at the bottom of the rectification tower in a condenser at the top of the cleaning tower, and a portion of the nitrogen gas condenses and descends as liquid nitrogen. This liquid nitrogen and the nitrogen gas supplied to the lower part of the cleaning tower come into contact with each other in a countercurrent state, and dust particles and other contaminants mixed in the nitrogen gas during compression are washed away by the liquid nitrogen. On the other hand, impure liquid oxygen is heated, and the gas that evaporates with this heating rises in countercurrent contact with liquid nitrogen (reflux liquid) descending in the rectification column, and the oxygen liquefies and descends. , the nitrogen-rich gas rises and undergoes rectification. The washed medium pressure nitrogen gas taken out from the top of the washing tower is used as a cooling source in the main heat exchanger and then taken out as a clean product medium pressure nitrogen gas. In addition, the liquid nitrogen taken out from the bottom of the cleaning tower is supercooled in a supercooler, expanded, and then supplied to the top of the rectification tower as a reflux liquid necessary for rectifying and separating nitrogen components from the raw air. This helps to further improve the nitrogen gas yield. [Effect of the invention] Therefore, the low-pressure nitrogen gas taken out from the top of the rectification tower is used as a cold source in the supercooler and the main heat exchanger, and then compressed and cooled to the lower part of the cleaning tower. The gas is supplied to the condenser at the top and used as a heating source for the impure liquid oxygen at the bottom of the rectifying column, and the medium-pressure nitrogen gas taken out from the top of the washing column is used as a cooling source for the main heat exchanger. By combining this and using the liquid nitrogen liquefied in the cleaning tower as the reflux liquid in the rectification tower, the yield of nitrogen gas can be improved and the amount per unit amount can be improved compared to conventional production methods. Manufacturing costs can be reduced. Moreover, the countercurrent contact between liquid nitrogen and nitrogen gas in the cleaning tower makes it possible to wash and remove dust particles and other contaminants from the nitrogen gas mixed in during compression. It is possible to continuously produce nitrogen gas as a product. [Example] First, a method for producing nitrogen gas according to the present invention will be explained based on FIG. After compressing raw air (GA) from which dust has been removed using an air filter (not shown) to the pressure required for air separation operation (for example, 4.7 Kg/cm 2 G) using compressor 1, this compressed raw air GA is Cooling, carbon removal,
Supplied to drying unit 2. In this cooling/removal/drying unit 2, compressed feed air GA is cooled to room temperature in an aftercooler, then cooled to approximately 5°C in a refrigeration equipment, and then cooled in one of the two molecular sieve towers. feedstock air
Adsorbs and removes carbon dioxide and moisture in GA. Meanwhile, waste gas (impure oxygen gas) that has passed through the main heat exchanger 3 (described later) is supplied to the other molecular sieve tower for regeneration. This cooling/removal/drying unit 2 removes carbon dioxide gas,
The raw air GA from which moisture and other impurities have been removed is supplied to the main heat exchanger 3 through pipe P2, cooled to near the liquefaction point, and then passed through pipe P3 to the rectification tower 4.
It is supplied to the lower raw material air supply section 4a. In addition, liquid nitrogen, which is an example of a cold source, is placed in the upper part of the rectification column 4.
LN is supplied through the pipe P4, and in the main rectification section 4b of the rectification column 4, the feed air rising from the bottom and liquid nitrogen (reflux liquid) descending from the top of the rectification column 4 are countercurrently flowed. Contact is made to liquefy oxygen from raw air GA and separate nitrogen gas. Nitrogen gas GN taken out from the top of the rectification column 4
to the supercooler 5 through the pipe P5, and then to the supercooler 5 through the pipe P5.
6 to the main heat exchanger 3, nitrogen gas GN
The cold energy is transferred to the supercooler 5 and the main heat exchanger 3.
In addition to being used as a cold source in
Warm to room temperature. The room-temperature nitrogen gas taken out from the main heat exchanger 3 through the pipe P21 is supplied to the compressor 6, and the nitrogen gas at almost the same pressure as the raw air GA is supplied.
GN (e.g. 4.0Kg/cm 2 G) to medium pressure (e.g. 9.0
Kg/cm 2 G). The compressed nitrogen gas taken out from the compressor 6 is returned to the main heat exchanger 3 through pipe P22, cooled to near the liquefaction point, and then passed through pipe P23 to the rectification tower 4.
The liquid nitrogen is supplied to the lower part of the liquid nitrogen cleaning tower 12 provided at the bottom of the tank. The nitrogen gas GN supplied into the cleaning tower 12 ascends through the cleaning section 12a and enters the cleaning tower 12.
Impure liquid oxygen reservoir section 4c at the top of the rectification column 4 bottom
The capacitor 12b is located inside the capacitor 12b.
heat exchanged with impure liquid oxygen L0 and nitrogen gas GN
Some of it condenses and descends as liquid nitrogen LN.
This liquid nitrogen LN and the nitrogen gas GN supplied to the lower part of the cleaning tower 12 come into contact with each other in a countercurrent state in the cleaning section 12a, and dust particles and other contaminants in the nitrogen gas GN mixed in during compression are removed from the liquid nitrogen. Washed and removed with LN. On the other hand, the impure liquid oxygen L0 is heated, and the gas evaporated as a result of this heating is transferred to the auxiliary rectification section 4d interposed between the raw air supply section 4a and the impure liquid oxygen storage section 4c of the rectification column 4. Liquid nitrogen (reflux liquid) rises to the top of the rectification column 4 through the column and descends inside the rectification column.
In countercurrent contact with the oxygen, the oxygen liquefies and descends,
The nitrogen-rich gas rises and undergoes rectification. Due to the two-stage rectification separation action in the auxiliary rectification section 4d and the main rectification section 4b, the rate of nitrogen gas can be improved. The washed medium-pressure nitrogen gas GN taken out from the top of the washing tower 12 through the pipe P24 is supplied to the main heat exchanger 3, and the cold energy of this medium-pressure nitrogen gas GN is used as a cold source in the main heat exchanger 3. After the medium pressure nitrogen gas GN is heated to room temperature during use, clean product medium pressure nitrogen gas is taken out from the main heat exchanger 3 through the pipe P25. Further, liquid nitrogen LN taken out from the bottom of the cleaning tower 12 through the pipe P12 is supplied to the supercooler 5,
After supercooling the liquid nitrogen LN, it is introduced into a pipe P13 having an expansion valve 8, expanded, and supplied to the upper part of the rectification column 4 as a reflux liquid. The impure liquid oxygen L0 taken out from the lower part of the impurity oxygen reservoir section 4c of the rectification column 4 is supplied to the supercooler 5 through the pipe P14, and after supercooling the impure liquid oxygen L0, the pipe having the expansion valve 9 Lead to P15,
It is expanded and supplied to a condenser 10 provided at the top of the rectification column 4. The impure liquid oxygen L0 evaporated under reduced pressure in the condenser 10 and the low-temperature nitrogen gas GN present in the upper part of the rectification column 4 exchange heat, and a part of the low-temperature nitrogen gas GN is liquefied and descends as a reflux liquid. . Impure oxygen gas G evaporated in the condenser 10
0 to the supercooler 5 through the pipe P16, and further,
It is supplied to the main heat exchanger 3 through the pipe P17, and the cold energy of the impure oxygen gas G0 is used as a cold source in the supercooler 5 and the main heat exchanger 3. The waste gas G0 of impure oxygen gas that has been warmed to room temperature as a result of this cold release is supplied to the unused molecular sieve tower of the cooling/carburization/drying unit 2 through the pipe P18 and is used as regeneration gas. After
released to the outside. In the above-mentioned embodiment, all of the nitrogen gas GN that was initially heated to room temperature in the main heat exchanger 3 is compressed and returned to the main heat exchanger 3, and only clean medium-pressure nitrogen gas is produced as a product. However, the production method is not limited to this method. For example, a part of the nitrogen gas GN that was first heated to room temperature in the main heat exchanger 3 may be converted into a low-pressure product nitrogen gas having approximately the same pressure as the raw material air GA. The remainder is compressed and returned to the main heat exchanger 3.
It may also be taken out as a clean intermediate pressure product nitrogen gas. In addition, in the above-mentioned embodiment, as a method of separately supplying cold during the entire process, the rectification tower 4 is supplied from the outside.
Although liquid nitrogen LN is supplied to the upper part of the main heat exchanger 3, it is not limited to this replenishment method. For example, as shown in FIG. A part of the extracted raw material air GA is adiabatically expanded in the expansion turbine 11, and then the cold raw material air is extracted from the expansion turbine 11 through the pipe P20 and is passed through the supercooler 5 to form a waste gas (impure oxygen gas) system. The raw air GA may be made to join the pipe P17, and then a part of this raw air GA may be supplied as a cold source for the main heat exchanger 3. Furthermore, in each of the above embodiments, two compressors were used: compressor 1 for compressing raw air and compressor 6 for compressing nitrogen gas that was first heated to room temperature in main heat exchanger 3. I explained the manufacturing method, but
It is not limited to this. In other words, considering the pressure levels of these two compressors 1 and 6,
By using the low pressure stage of the same compressor for raw air compression and the high pressure stage for nitrogen gas compression, a single compressor can be used for both purposes. Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.
第１図および第２図は本発明に係る実施例を示
し、第１図は窒素ガス製造方法を示す配管系統
図、第２図は別実施例を示す配管系統図である。
３…主熱交換器、４…精溜塔、４ａ…原料空気
供給部、４ｂ…主精溜部、４ｃ…不純液体酸素溜
部、４ｄ…補助精溜部、５…過冷却器、１０…コ
ンデンサ、１１…膨張タービン、１２…液体窒素
洗浄塔、１２ａ…洗浄部、１２ｂ…コンデンサ。
1 and 2 show an embodiment according to the present invention, FIG. 1 is a piping system diagram showing a nitrogen gas production method, and FIG. 2 is a piping system diagram showing another embodiment. 3... Main heat exchanger, 4... Rectifying column, 4a... Raw air supply section, 4b... Main rectifying section, 4c... Impure liquid oxygen reservoir section, 4d... Auxiliary rectifying section, 5... Supercooler, 10... Condenser, 11... Expansion turbine, 12... Liquid nitrogen cleaning tower, 12a... Cleaning section, 12b... Condenser.
Claims (1)
除去した後、主熱交換器３において液化点付近ま
で冷却して精溜塔４の下部に供給し、精溜により
塔頂から製品窒素ガスを取出し、製造系外へ導出
する窒素ガス製造方法であつて、精溜塔４の塔頂
から取出した窒素ガスを過冷却器５、主熱交換器
３の寒冷源として使用して常温まで加温し、この
窒素ガスの少なくとも一部を圧縮した後、主熱交
換器３に戻して液化点付近まで冷却し、精溜塔４
の底部に設けられた液体窒素洗浄塔１２の下部に
供給して塔の洗浄部１２ａ内を上昇させ、洗浄塔
１２頂部に設けられたコンデンサ１２ｂで精溜塔
４底部の不純液体酸素により冷却液化されて下降
する液体窒素と向流状態で接触させて不純物を洗
浄除去した後、洗浄塔１２の塔頂から取出し、再
び主熱交換器３で常温まで加温して清浄な製品中
圧窒素ガスとして取出し、洗浄塔１２の底部から
取出された液体窒素は前記過冷却器５で過冷却
後、膨張させて精溜塔４の上部に還流液として供
給すると共に、全工程中において別途に寒冷を補
給することを特徴とする窒素ガス製造方法。 ２ 前記不純液体酸素から蒸発したガスを精溜塔
４の、原料空気供給部４ａと不純液体酸素溜部４
ｃとの間に介在された補助精溜部４ｄを通して精
溜塔４の主精溜部４ｂに上昇させる特許請求の範
囲第１項に記載の窒素ガス製造方法。 ３ 前記別途補給される寒冷が、外部から精溜塔
４の上部に供給される液体窒素である特許請求の
範囲第１項又は第２項に記載の窒素ガス製造方
法。 ４ 前記別途補給される寒冷が、主熱交換器３の
中間から取出されて膨張タービン１１で膨張さ
れ、精溜塔４の上部に設けられたコンデンサ１０
から取出され、過冷却器５で加温された廃ガスで
ある不純酸素ガスと合流して主熱交換器３の寒冷
源として用いられる原料空気の一部である特許請
求の範囲第１項又は第２項に記載の窒素ガス製造
方法。 ５ 前記主熱交換器３で最初に常温まで加温され
た窒素ガスの所要量を原料空気とほぼ同圧の低圧
製品窒素ガスとして取出し、残部を圧縮して主熱
交換器３へ戻す特許請求の範囲第３項又は第４項
に記載の窒素ガス製造方法。[Claims] 1. Compressed air is used as a raw material, and after removing moisture, carbon dioxide, etc., it is cooled to near the liquefaction point in the main heat exchanger 3, and then supplied to the lower part of the rectification column 4, where it is rectified into the column. A nitrogen gas production method in which product nitrogen gas is taken out from the top and led out of the production system, and the nitrogen gas taken out from the top of the rectification column 4 is used as a cooling source for the supercooler 5 and the main heat exchanger 3. After compressing at least a portion of this nitrogen gas, it is returned to the main heat exchanger 3 and cooled to near the liquefaction point, and then passed through the rectification column 4.
The liquid nitrogen is supplied to the lower part of the cleaning tower 12 installed at the bottom of the tower, and is raised inside the cleaning section 12a of the tower, and is cooled and liquefied by the impure liquid oxygen at the bottom of the rectification tower 4 in the condenser 12b installed at the top of the cleaning tower 12. After cleaning and removing impurities by contacting the descending liquid nitrogen in a countercurrent state, it is taken out from the top of the cleaning tower 12, and heated to room temperature again in the main heat exchanger 3 to produce a clean medium-pressure nitrogen gas product. The liquid nitrogen taken out from the bottom of the cleaning tower 12 is supercooled in the supercooler 5, expanded, and supplied to the upper part of the rectification tower 4 as a reflux liquid. A method for producing nitrogen gas, characterized by supplying nitrogen gas. 2 The gas evaporated from the impure liquid oxygen is transferred to the raw air supply section 4a and the impure liquid oxygen storage section 4 of the rectification column 4.
The method for producing nitrogen gas according to claim 1, wherein the nitrogen gas is raised to the main rectification section 4b of the rectification column 4 through the auxiliary rectification section 4d interposed between the nitrogen gas and the auxiliary rectification section 4d. 3. The nitrogen gas production method according to claim 1 or 2, wherein the separately supplied cold is liquid nitrogen supplied to the upper part of the rectification column 4 from the outside. 4 The separately replenished cold is taken out from the middle of the main heat exchanger 3 and expanded in the expansion turbine 11, and then transferred to the condenser 10 provided at the upper part of the rectification column 4.
Claim 1, or The method for producing nitrogen gas according to item 2. 5. A patent claim in which the required amount of nitrogen gas that is first heated to room temperature in the main heat exchanger 3 is taken out as a low-pressure product nitrogen gas having approximately the same pressure as the raw material air, and the remainder is compressed and returned to the main heat exchanger 3. The method for producing nitrogen gas according to item 3 or 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32021390A JPH03230079A (en) | 1990-11-22 | 1990-11-22 | Preparation of nitrogen gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32021390A JPH03230079A (en) | 1990-11-22 | 1990-11-22 | Preparation of nitrogen gas |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5095186A Division JPS62206373A (en) | 1986-03-07 | 1986-03-07 | Manufacture of nitrogen gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03230079A JPH03230079A (en) | 1991-10-14 |
| JPH0427476B2 true JPH0427476B2 (en) | 1992-05-11 |
Family
ID=18118983
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32021390A Granted JPH03230079A (en) | 1990-11-22 | 1990-11-22 | Preparation of nitrogen gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03230079A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5511380A (en) * | 1994-09-12 | 1996-04-30 | Liquid Air Engineering Corporation | High purity nitrogen production and installation |
| DE10157544A1 (en) * | 2001-11-23 | 2003-06-12 | Messer Ags Gmbh | Method and device for producing nitrogen from air |
| JP5005894B2 (en) * | 2005-06-23 | 2012-08-22 | エア・ウォーター株式会社 | Nitrogen generation method and apparatus used therefor |
-
1990
- 1990-11-22 JP JP32021390A patent/JPH03230079A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03230079A (en) | 1991-10-14 |
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