FR2861841A1 - METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION - Google Patents

METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION Download PDF

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Publication number
FR2861841A1
FR2861841A1 FR0350779A FR0350779A FR2861841A1 FR 2861841 A1 FR2861841 A1 FR 2861841A1 FR 0350779 A FR0350779 A FR 0350779A FR 0350779 A FR0350779 A FR 0350779A FR 2861841 A1 FR2861841 A1 FR 2861841A1
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Prior art keywords
air
pressure column
column
medium
sent
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FR0350779A
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French (fr)
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FR2861841B1 (en
Inventor
Bihan Herve Le
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Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to FR0350779A priority Critical patent/FR2861841B1/en
Priority to CNB200480030919XA priority patent/CN100538233C/en
Priority to EP04805780A priority patent/EP1690053A1/en
Priority to US10/576,826 priority patent/US20070137248A1/en
Priority to JP2006537385A priority patent/JP2007510879A/en
Priority to PCT/FR2004/050537 priority patent/WO2005045339A1/en
Publication of FR2861841A1 publication Critical patent/FR2861841A1/en
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Publication of FR2861841B1 publication Critical patent/FR2861841B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04163—Hot end purification of the feed air
    • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
    • F25J3/04175—Hot end purification of the feed air by adsorption of the impurities at a pressure of substantially more than the highest pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04048—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams
    • F25J3/04054—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams of 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • F25J3/04296—Claude expansion, i.e. expanded into the main or 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
    • 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
    • F25J3/0446—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 the heat generated by mixing two different phases
    • F25J3/04466—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 the heat generated by mixing two different phases for producing oxygen as a mixing column overhead gas by mixing gaseous air feed and liquid 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
    • F25J3/04872—Vertical layout of cold equipments within in the cold box, e.g. columns, heat exchangers etc.
    • 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
    • F25J2200/04—Processes or apparatus using separation by rectification in a dual pressure main column system
    • F25J2200/06—Processes or apparatus using separation by rectification in a dual pressure main column system in a classical double column flow-sheet, 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
    • 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/50—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being 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
    • F25J2245/50—Processes or apparatus involving steps for recycling of process streams the recycled stream being 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
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/12—Particular process parameters like pressure, temperature, ratios

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  • 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

Dans un procédé de séparation d'air par distillation cryogénique dans une installation comprenant une colonne moyenne pression (3), une colonne basse pression (4) et une colonne de mélange (6), on comprime de l'air dans un compresseur (C01), on le refroidit dans une ligne d'échange (1) et on envoie une première partie (2) de l'air à la cuve de la colonne de mélange, on envoie une deuxième partie de l'air à la colonne moyenne pression où il se sépare, on envoie un liquide enrichi en oxygène (19) et un liquide enrichi en azote (11) de la colonne moyenne pression vers la colonne basse pression, on envoie un liquide riche en oxygène (26) de la colonne basse pression vers la tête de la colonne de mélange, on soutire au moins un débit de liquide (27, 29) de la colonne moyenne ou basse pression, on surpresse la deuxième partie de l'air dans un surpresseur (8), on le refroidit dans la ligne d'échange, on la divise en une première fraction et une deuxième fraction, on refroidit la première fraction de l'air dans la ligne d'échange, on le liquéfie au moins partiellement et on l'envoie à la colonne moyenne pression et/ou la colonne basse pression, on détend la deuxième fraction de l'air dans une turbine Claude (9) et on l'envoie à la colonne moyenne pression et on soutire un débit riche en oxygène (18) de la colonne de mélange et on le réchauffe dans la ligne d'échange.In a process for separating air by cryogenic distillation in an installation comprising a medium pressure column (3), a low pressure column (4) and a mixing column (6), air is compressed in a compressor (C01 ), it is cooled in an exchange line (1) and a first portion (2) of the air is sent to the tank of the mixing column, a second part of the air is sent to the medium pressure column where it separates, an oxygen-enriched liquid (19) and a nitrogen-enriched liquid (11) from the medium-pressure column are sent to the low-pressure column, an oxygen-rich liquid (26) is sent from the low-pressure column towards the head of the mixing column, at least one liquid flow (27, 29) is withdrawn from the medium or low pressure column, the second part of the air is overheated in a booster (8), cooled in the exchange line, divide it into a first fraction and a second fraction, oidit the first fraction of the air in the exchange line, it is liquefied at least partially and sent to the medium pressure column and / or the low pressure column, the second fraction of the air is relaxed in a Claude turbine (9) and is sent to the medium pressure column and a rich oxygen flow (18) is withdrawn from the mixing column and warmed in the exchange line.

Description

2861841 12861841 1

La présente invention est relative à un procédé et à un appareil de séparation d'air par distillation cryogénique. En particulier il concerne un procédé de séparation d'air utilisant une colonne de mélange pour la production d'oxygène gazeux impur.  The present invention relates to a method and apparatus for air separation by cryogenic distillation. In particular, it relates to an air separation process using a mixing column for the production of impure oxygen gas.

Il est connu de EP-A-0538118 d'utiliser une double colonne et une colonne de mélange pour produire de l'oxygène impur avec un surpresseur dédié d'air pour comprimer l'air à la pression de la colonne de mélange.  It is known from EP-A-0538118 to use a double column and a mixing column to produce impure oxygen with a dedicated air booster to compress the air at the pressure of the mixing column.

La présente invention vise à réduire les coûts d'investissement d'un tel appareil.  The present invention aims to reduce the investment costs of such a device.

Selon un objet de l'invention, il est prévu un procédé de séparation d'air par distillation cryogénique dans une installation comprenant une colonne moyenne pression, une colonne basse pression et une colonne de mélange dans lequel i) on comprime de l'air dans un compresseur, on le refroidit dans une ligne d'échange et on envoie une première partie de l'air à la cuve de la colonne de mélange ii) on envoie une deuxième partie de l'air à la colonne moyenne pression où il se sépare iii) on envoie un liquide enrichi en oxygène et un liquide enrichi en azote de la colonne moyenne pression vers la colonne basse pression iv) on envoie un liquide riche en oxygène de la colonne basse pression vers la tête de la colonne de mélange v) on soutire au moins un débit de liquide de la colonne moyenne ou basse pression vi) on surpresse la deuxième partie de l'air dans un surpresseur, on le refroidit dans la ligne d'échange, on la divise en une première fraction et une deuxième fraction vii) on refroidit la première fraction de l'air dans la ligne d'échange, on le liquéfie au moins partiellement et on l'envoie à la colonne moyenne pression et/ou la colonne basse pression viii) on détend la deuxième fraction de l'air dans une turbine Claude et on l'envoie à la colonne moyenne pression et ix) on soutire un débit riche en oxygène de la colonne de mélange et on le réchauffe dans la ligne d'échange.  According to an object of the invention, there is provided a method of air separation by cryogenic distillation in an installation comprising a medium pressure column, a low pressure column and a mixing column in which i) air is compressed in a compressor, it is cooled in a line of exchange and a first part of the air is sent to the tank of the mixing column ii) a second part of the air is sent to the medium pressure column where it separates iii) an oxygen-enriched liquid and a nitrogen-enriched liquid are sent from the medium-pressure column to the low-pressure column; iv) an oxygen-rich liquid is sent from the low-pressure column to the top of the mixing column; withdraws at least one liquid flow from the medium or low pressure column vi) the second part of the air is overheated in a booster, it is cooled in the exchange line, it is divided into a first fraction and a second fraction action vii) the first fraction of air is cooled in the exchange line, at least partially liquefied and sent to the medium pressure column and / or the low pressure column viii) the second fraction of The air in a Claude turbine is sent to the medium pressure column and ix) a rich oxygen flow is withdrawn from the mixing column and heated in the exchange line.

Selon d'autres aspects facultatifs: 2861841 2 - le liquide soutiré de la colonne moyenne ou basse pression est un produit final - le surpresseur est couplé à la turbine Claude.  According to other optional aspects: 2861841 2 - the liquid withdrawn from the medium or low pressure column is a final product - the booster is coupled to the Claude turbine.

- le surpresseur est un surpresseur froid.  - the booster is a cold booster.

- la colonne de mélange opère à entre 8 et 20 bars abs.  the mixing column operates at between 8 and 20 bar abs.

- tout l'air destiné à la distillation est comprimé à entre 8 et 20 bars abs.  all the air for distillation is compressed to between 8 and 20 bar abs.

- entre 40 et 90 % de l'air destiné à la distillation est surpressé.  - Between 40 and 90% of the air for distillation is overpressed.

- l'air surpressé est surpressé à entre 12 et 30 bars abs.  - the supercharged air is boosted to between 12 and 30 bar abs.

Selon un autre aspect de l'invention, il est prévu une installation de séparation d'air par distillation cryogénique dans un appareil comprenant une colonne moyenne pression, une colonne basse pression et une colonne de mélange, une turbine Claude, un surpresseur, des moyens pour comprimer de l'air, des moyens pour envoyer une partie de l'air comprimé de l'air à la colonne de mélange, des moyens pour envoyer une autre partie de l'air comprimé au surpresseur, des moyens pour envoyer une fraction de l'air surpressé à la turbine Claude et pour envoyer l'air détendu à la colonne moyenne pression, des moyens pour envoyer le reste de l'air surpressé à la colonne moyenne pression et/ou basse pression après liquéfaction et détente et des moyens pour soutirer au moins un liquide de la colonne moyenne pression et/ou de la colonne basse pression comme produit final.  According to another aspect of the invention, there is provided an air separation installation by cryogenic distillation in an apparatus comprising a medium pressure column, a low pressure column and a mixing column, a Claude turbine, a booster, means for compressing air, means for feeding a portion of the compressed air from the air to the mixing column, means for sending another part of the compressed air to the booster, means for sending a fraction of the pressurized air to the turbine Claude and to send the expanded air to the medium-pressure column, means for sending the rest of the pressurized air to the medium pressure column and / or low pressure after liquefaction and relaxation and means for withdrawing at least one liquid from the medium pressure column and / or the low pressure column as final product.

Le surpresseur peut être couplé à la turbine Claude.  The booster can be coupled to the Claude turbine.

Un exemple de mise en oeuvre de l'invention vont maintenant être décrits en regard du dessin annexé, sur lequel la figure 1 représente schématiquement un mode de réalisation de l'installation de distillation d'air conforme à l'invention.  An exemplary implementation of the invention will now be described with reference to the accompanying drawing, in which Figure 1 shows schematically an embodiment of the air distillation plant according to the invention.

L'installation de distillation d'air représentée à la figure 1 est destinée à produire de l'oxygène impur OI, par exemple ayant une pureté de 80 à 97 % et de préférence de 85 à 95 % sous une pression déterminée P nettement différente de 6 x 105 Pa abs., par exemple sous 8 à 20 x 105 Pa. L'installation comprend essentiellement une ligne d'échange thermique 1, une double colonne de distillation comprenant elle-même une colonne moyenne pression 3, une colonne basse pression 4 et un condenseurvaporiseur principal 5, et une colonne de mélange 6. La colonne de mélange 6 et la colonne basse pression 4 sont intégrées dans une seule structure. La colonne moyenne pression 3 forme une structure à part et est surmontée du condenseur-vaporiseur 5, comme décrit dans 3 S6385 0. 1/04 EP-A-1978212. Les colonnes 3 et 4 fonctionnent typiquement sous environ 6 x 105 Pa et environ 1 x 105 Pa respectivement.  The air distillation plant shown in FIG. 1 is intended to produce impure oxygen OI, for example having a purity of 80 to 97% and preferably of 85 to 95% at a determined pressure P which is distinctly different from 6 x 105 Pa absolute, for example under 8 to 20 x 105 Pa. The installation essentially comprises a heat exchange line 1, a double distillation column including itself a medium pressure column 3, a low pressure column 4 and a main condenser 5, and a mixing column 6. The mixing column 6 and the low pressure column 4 are integrated in a single structure. The medium pressure column 3 forms a separate structure and is surmounted by the condenser-vaporizer 5, as described in 3 S6385 0. 1/04 EP-A-1978212. Columns 3 and 4 typically operate at about 6 x 105 Pa and about 1 x 105 Pa respectively.

Comme expliqué en détail dans le document US-A-4,022,030, une colonne de mélange est une colonne qui a la même structure qu'une colonne de distillation mais qui est utilisée pour mélanger de façon proche de la réversibilité un gaz relativement volatil, introduit à sa base, et un liquide moins volatil, introduit à son sommet.  As explained in detail in US-A-4,022,030, a mixing column is a column which has the same structure as a distillation column but which is used to mix relatively reversibly a relatively volatile gas introduced at its base, and a less volatile liquid, introduced at its summit.

Un tel mélange produit de l'énergie frigorifique et permet donc de réduire la consommation d'énergie liée à la distillation. Dans le cas présent, ce mélange est mis à profit, en outre, pour produire directement de l'oxygène impur sous la pression P, comme cela sera décrit ci-dessous.  Such a mixture produces cooling energy and thus reduces the energy consumption associated with the distillation. In the present case, this mixture is further exploited to directly produce impure oxygen under pressure P, as will be described below.

L'air à séparer par distillation est comprimé à 15 x 105 Pa (en général entre 8 et 20 x 105 Pa) dans un compresseur C01 et convenablement épuré, est divisé en deux. Une partie de cet air constituant entre 40 et 90% de l'air est surpressée dans un surpresseur 8 jusqu'à une pression d'entre 12 et 30 x 105 Pa, refroidie dans la ligne d'échange 1 et divisé en deux fractions. Une fraction poursuit son refroidissement dans la ligne d'échange 1 où elle se liquéfie au moins partiellement avant d'être introduite à la colonne moyenne pression 3 par une conduite 7. Une partie ou tout cet air liquéfié peut être envoyé à la colonne basse pression 4. Une autre fraction de l'air surpressé en 8 puis refroidie, est détendue à la moyenne pression dans une turbine Claude 9 couplée au surpresseur 8, puis envoyé en cuve de la colonne moyenne pression 3 sous forme gazeuse, quelques plateaux en dessous du point d'arrivée de la conduite 7. Du liquide riche (air enrichi en oxygène), prélevé en cuve de la colonne 3 est, après détente dans une vanne de détente 10, introduit dans la colonne 4. Du liquide pauvre (azote impur) 11 prélevé en haut de la colonne 3 est, après détente dans une vanne de détente 12, introduit au sommet de la colonne 4, et le gaz produit en tête de la colonne 4 constituant le gaz résiduaire NI de l'installation est réchauffé dans la ligne d'échange 1 et évacué de l'installation.  The air to be distilled off is compressed at 15 × 10 5 Pa (usually between 8 and 20 × 10 5 Pa) in a C01 compressor and suitably purified, is divided in half. Part of this air constituting between 40 and 90% of the air is overpressed in a booster 8 to a pressure of between 12 and 30 x 105 Pa, cooled in the exchange line 1 and divided into two fractions. A fraction continues cooling in the exchange line 1 where it liquefies at least partially before being introduced to the medium pressure column 3 by a pipe 7. Part or all of this liquefied air can be sent to the low pressure column 4. Another fraction of the compressed air 8 and cooled, is relaxed at medium pressure in a Claude 9 turbine coupled to the booster 8, then sent to the bottom of the medium pressure column 3 in gaseous form, some trays below the arrival point of the pipe 7. The rich liquid (oxygen-enriched air) taken from the bottom of column 3 is, after expansion in an expansion valve 10, introduced into column 4. Lean liquid (impure nitrogen) 11 taken at the top of the column 3 is, after expansion in an expansion valve 12, introduced at the top of the column 4, and the gas produced at the top of the column 4 constituting the waste gas NI of the facility is rec haggled in the exchange line 1 and evacuated from the installation.

De l'oxygène liquide, plus ou moins pur suivant le réglage de la double colonne, est soutiré en cuve de la colonne 4, envoyé par la conduite 24 au condenseur-vaporiseur 5 où il se vaporise partiellement formant un gaz 25 qui est renvoyé à la colonne basse pression 4. Du liquide 26 est soutiré du condenseur 5, porté par une pompe 13 à une pression P1, légèrement supérieure à la pression P S6385 01/04 précitée pour tenir compte des pertes de charge (Pl-P inférieur à 1 x 105 Pa), et en partie introduit au sommet de la colonne 6. Une partie 27 de l'oxygène liquide peut être envoyé à un stockage. De l'air auxiliaire provenant du compresseur C01, comprimé à une pression largement au-dessus de la moyenne pression et refroidi partiellement dans la ligne d'échange 1, est introduit à la base de la colonne de mélange 6. De cette dernière sont soutirés trois courants de fluide: à sa base, du liquide voisin du liquide riche et réuni à ce dernier via une conduite 15 munie d'une vanne de détente 15A; en un point intermédiaire, un mélange essentiellement constitué d'oxygène et d'azote, qui est renvoyé en un point intermédiaire de la colonne basse pression 4 via une conduite 16 munie d'une vanne de détente 17; et à son sommet de l'oxygène impur, qui, après réchauffement dans la ligne d'échange thermique, est évacué, sensiblement à la pression P, de l'installation via une conduite 18 en tant que gaz de production 01.  Liquid oxygen, more or less pure according to the setting of the double column, is withdrawn in the vat of column 4, sent via line 24 to condenser-vaporizer 5 where it vaporizes partially forming a gas 25 which is returned to the low pressure column 4. Liquid 26 is withdrawn from the condenser 5, carried by a pump 13 at a pressure P1, slightly greater than the aforementioned pressure P S6385 01/04 to take account of the pressure drops (P1-P less than 1 x 105 Pa), and partly introduced at the top of the column 6. Part 27 of the liquid oxygen can be sent to a storage. Auxiliary air from the compressor C01, compressed at a pressure well above the medium pressure and partially cooled in the exchange line 1, is introduced at the base of the mixing column 6. From the latter are withdrawn three fluid streams: at its base, liquid adjacent the rich liquid and joined to the latter via a pipe 15 provided with an expansion valve 15A; at an intermediate point, a mixture consisting essentially of oxygen and nitrogen, which is returned to an intermediate point of the low pressure column 4 via a pipe 16 provided with an expansion valve 17; and at its top impure oxygen, which, after heating in the heat exchange line, is evacuated, substantially at the pressure P, from the installation via a pipe 18 as a production gas 01.

Un débit d'azote liquide est soutiré en tête de la colonne moyenne pression 3 comme produit final.  A flow of liquid nitrogen is withdrawn at the top of the medium pressure column 3 as the final product.

On a également représenté sur la figure 1 des échangeurs de chaleur auxiliaires 19, 20 assurant la récupération du froid disponible dans les fluides en circulation dans l'installation.  FIG. 1 also shows auxiliary heat exchangers 19, 20 for recovering the cold available in the fluids circulating in the installation.

II sera aisément compris que la double colonne composée des colonnes 3 et 4 peut former une seule structure de façon classique, la colonne de mélange 6 formant une structure à part.  It will be readily understood that the double column composed of the columns 3 and 4 can form a single structure in a conventional manner, the mixing column 6 forming a separate structure.

Eventuellement un débit d'oxygène liquide pressurisé et/ou un débit d'azote liquide pressurisé peut se vaporiser dans la ligne d'échange 1 ou dans un vaporiseur dédié.  Optionally a flow of pressurized liquid oxygen and / or a flow of pressurized liquid nitrogen may vaporize in the exchange line 1 or in a dedicated vaporizer.

Claims (10)

REVENDICATIONS 1. Procédé de séparation d'air par distillation cryogénique dans une installation comprenant une colonne moyenne pression (3), une colonne basse pression (4) et une colonne de mélange (6) dans lequel i) on comprime de l'air dans un compresseur (C01), on le refroidit dans une ligne d'échange (1) et on envoie une première partie (2) de l'air à la cuve de la colonne de mélange ii) on envoie une deuxième partie de l'air à la colonne moyenne pression où il se sépare iii) on envoie un liquide enrichi en oxygène (19) et un liquide enrichi en azote (11) de la colonne moyenne pression vers la colonne basse pression iv) on envoie un liquide riche en oxygène (26) de la colonne basse pression vers la tête de la colonne de mélange v) on soutire au moins un débit de liquide (29) de la colonne moyenne ou basse pression vi) on surpresse la deuxième partie de l'air dans un surpresseur (8), on le refroidit dans la ligne d'échange, on la divise en une première fraction et une deuxième fraction vii) on refroidit la première fraction de l'air dans la ligne d'échange, on le liquéfie au moins partiellement et on l'envoie à la colonne moyenne pression et/ou la colonne basse pression viii) on détend la deuxième fraction de l'air dans une turbine Claude (9) et on l'envoie à la colonne moyenne pression et ix) on soutire un débit riche en oxygène (18) de la colonne de mélange et on le réchauffe dans la ligne d'échange.  A method of separating air by cryogenic distillation in an installation comprising a medium pressure column (3), a low pressure column (4) and a mixing column (6) in which i) air is compressed in a compressor (C01), is cooled in an exchange line (1) and sends a first portion (2) of air to the tank of the mixing column ii) a second part of the air is sent to the middle pressure column where it separates iii) an oxygen-enriched liquid (19) and a nitrogen-enriched liquid (11) from the medium-pressure column are sent to the low-pressure column iv) an oxygen-rich liquid is sent (26). ) from the low pressure column to the top of the mixing column v) at least one liquid flow (29) is withdrawn from the medium or low pressure column vi) the second part of the air is overpressed in a booster (8) ), it is cooled in the exchange line, it is divided into a first fraction and a second fraction vii) the first fraction of air is cooled in the exchange line, at least partially liquefied and sent to the medium pressure column and / or the low pressure column viii) the second fraction is expanded air in a Claude turbine (9) and sent to the medium pressure column and ix) a rich oxygen flow (18) is withdrawn from the mixing column and warmed in the exchange line. 2. Procédé selon la revendication 1 dans lequel le liquide (27, 29) soutiré de la colonne moyenne ou basse pression est un produit final.  2. Method according to claim 1 wherein the liquid (27, 29) withdrawn from the medium or low pressure column is a final product. 3. Procédé selon la revendication 1 ou 2 dans lequel le surpresseur (8) est couplé à la turbine Claude (9).  3. Method according to claim 1 or 2 wherein the booster (8) is coupled to the Claude turbine (9). 15 20 25 2861841 6  15 20 25 2861841 6 4. Procédé selon la revendication 1, 2 ou 3 dans lequel le surpresseur est un surpresseur froid.4. The method of claim 1, 2 or 3 wherein the booster is a cold booster. 5. Procédé selon l'une des revendications précédentes dans lequel la colonne de mélange (6) opère à entre 8 et 20 bars abs.  5. Method according to one of the preceding claims wherein the mixing column (6) operates at between 8 and 20 bar abs. 6. Procédé selon l'une des revendications précédentes dans lequel tout l'air destiné à la distillation est comprimé à entre 8 et 20 bars abs.  6. Method according to one of the preceding claims wherein all the air for distillation is compressed to between 8 and 20 bar abs. 7. Procédé selon l'une des revendications précédentes dans lequel entre 40 et 90 % de l'air destiné à la distillation est surpressé.  7. Method according to one of the preceding claims wherein between 40 and 90% of the air for distillation is overpressed. 8. Procédé selon l'une des revendications précédentes dans lequel l'air surpressé est surpressé à entre 12 et 30 bars abs.  8. Method according to one of the preceding claims wherein the pressurized air is boosted to between 12 and 30 bar abs. 9. Installation de séparation d'air par distillation cryogénique dans un appareil comprenant une colonne moyenne pression (3), une colonne basse pression (4) et une colonne de mélange (6), une turbine Claude (9), un surpresseur (8), des moyens pour comprimer de l'air (CO1), des moyens (2) pour envoyer une partie de l'air comprimé de l'air à la colonne de mélange, des moyens pour envoyer une autre partie de l'air comprimé au surpresseur, des moyens pour envoyer une fraction de l'air surpressé à la turbine Claude et pour envoyer l'air détendu à la colonne moyenne pression, des moyens pour envoyer le reste de l'air surpressé à la colonne moyenne pression et/ou basse pression après liquéfaction et détente et des moyens pour soutirer au moins un liquide (27, 29) de la colonne moyenne pression et/ou de la colonne basse pression comme produit final.  9. Apparatus for separating air by cryogenic distillation in an apparatus comprising a medium pressure column (3), a low pressure column (4) and a mixing column (6), a Claude turbine (9), a booster (8) ), means for compressing air (CO1), means (2) for feeding a portion of the compressed air from the air to the mixing column, means for sending another part of the compressed air the booster, means for sending a fraction of the air pressure to the turbine Claude and to send the expanded air to the medium pressure column, means for sending the rest of the pressurized air to the medium pressure column and / or low pressure after liquefaction and expansion and means for withdrawing at least one liquid (27, 29) from the medium pressure column and / or the low pressure column as final product. 10. Installation selon la revendication 9 dans lequel le surpresseur (8) est couplé à la turbine Claude (9).  10. Installation according to claim 9 wherein the booster (8) is coupled to the Claude turbine (9).
FR0350779A 2003-11-04 2003-11-04 METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION Expired - Fee Related FR2861841B1 (en)

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CNB200480030919XA CN100538233C (en) 2003-11-04 2004-10-26 The method and apparatus of separating air by cryogenic distillation
EP04805780A EP1690053A1 (en) 2003-11-04 2004-10-26 Method and device for separating air by cryogenic distillation
US10/576,826 US20070137248A1 (en) 2003-11-04 2004-10-26 Method and apparatus for separating air by cryogenic distillation
JP2006537385A JP2007510879A (en) 2003-11-04 2004-10-26 Method and apparatus for separating air by cryogenic distillation
PCT/FR2004/050537 WO2005045339A1 (en) 2003-11-04 2004-10-26 Method and device for separating air by cryogenic distillation

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EP1690053A1 (en) 2006-08-16
WO2005045339A1 (en) 2005-05-19
FR2861841B1 (en) 2006-06-30

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