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EP0869322A1 - Process and plant for air separation by cryogenic distillation - Google Patents

Process and plant for air separation by cryogenic distillation Download PDF

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Publication number
EP0869322A1
EP0869322A1 EP98400803A EP98400803A EP0869322A1 EP 0869322 A1 EP0869322 A1 EP 0869322A1 EP 98400803 A EP98400803 A EP 98400803A EP 98400803 A EP98400803 A EP 98400803A EP 0869322 A1 EP0869322 A1 EP 0869322A1
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EP
European Patent Office
Prior art keywords
column
liquid
turbine
air
distillation
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.)
Withdrawn
Application number
EP98400803A
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German (de)
French (fr)
Inventor
Martine Pelle
Norbert Rieth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing date
Publication date
Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Publication of EP0869322A1 publication Critical patent/EP0869322A1/en
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
    • F25J3/04096—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of argon or argon enriched 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
    • 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
    • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
    • F25J3/04084—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression 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
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
    • F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04333—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
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04387—Details relating to the work expansion, e.g. process parameter etc. using liquid or hydraulic turbine expansion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • 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
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • 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
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04666—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system
    • F25J3/04672—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system having a top condenser
    • 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
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
    • F25J2240/10—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream the fluid being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
    • F25J2240/12—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream the fluid being nitrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S62/00—Refrigeration
    • Y10S62/902—Apparatus
    • Y10S62/91—Expander

Definitions

  • the present invention relates to a method and an installation for air separation by cryogenic distillation.
  • Air separation by cryogenic means involves the use of a generation of cold or a source of cold.
  • FR-A-2 335 809 describes a device with a single turbine which provides all the frigories necessary for the process.
  • the expanded gas in the turbine can be medium pressure air or nitrogen. Supressed air is liquefied by exchange of heat with pressurized liquid oxygen which vaporizes.
  • US-A-5,564,290 describes a process in which pressurized air, condensed by the vaporization of the pumped liquid oxygen, then vaporizes in a turbine to produce a two-phase flow.
  • the present invention aims to improve performance energy of known devices.
  • a method of air separation by cryogenic distillation in which the air cools in an exchanger main and is sent to a distillation column of an apparatus comprising at least one distillation column where it separates into a liquid enriched in oxygen and nitrogen-enriched vapor, and pressurized liquid flow from the device vaporizes in the main exchanger, the frigories necessary for the process being generated by expansion of a circulating fluid in one or more turbines characterized in that the or all of the turbines the device produces a discharge which is at least 95% liquid, especially 100% liquid.
  • a single hydraulic turbine keeps cold without help of a turbine which expands gas to a pressure below the pressure supercritical. This reduction in investment is made possible by improving the performance of plate heat exchangers (minimum ⁇ T between 2 ° C and 1 ° C) where low spread losses and because of yields improved hydraulic turbines of the latest generations.
  • the invention proves to be particularly advantageous in the case where there is argon production because it improves the reflux rate inside the main column.
  • FIG. 1 The installation for producing gaseous oxygen under pressure shown in Figure 1 essentially includes an exchange line thermal 1 intended to cool the air to be treated by indirect heat exchange at counter current with cold products; an air distillation apparatus 2 of the type double column, consisting essentially of a medium pressure column 4 surmounted by a low pressure column 3, with a vaporizer-condenser 5 relating the indirect heat exchange to the overhead vapor (nitrogen) of column 4 and the tank liquid (oxygen) of column 3, a sub-cooler 6, an air expansion turbine 9 and a liquid oxygen pump 7.
  • an exchange line thermal 1 intended to cool the air to be treated by indirect heat exchange at counter current with cold products
  • an air distillation apparatus 2 of the type double column consisting essentially of a medium pressure column 4 surmounted by a low pressure column 3, with a vaporizer-condenser 5 relating the indirect heat exchange to the overhead vapor (nitrogen) of column 4 and the tank liquid (oxygen) of column 3, a sub-cooler 6, an air expansion turbine 9 and a liquid oxygen pump 7.
  • the rich liquid 31 and the liquid nitrogen 33 withdrawn at the head of column 4 are sub-cooled in sub-cooler 6 by low pressure impure nitrogen 25 produced at the head of column 3 then, after expansion in expansion valves respectively, feed this column low pressure 3.
  • the impure nitrogen low pressure After heating in 6 then in 1 the impure nitrogen low pressure, at room temperature can be used to regenerate a device of purification.
  • This air 13 is expanded at medium pressure in the turbine 9 in order to form a liquid flow.
  • Part of the liquid 19 is sent to the medium pressure column 4 and the rest 17 is relaxed in a valve before being sent to the column low pressure 3.
  • nitrogen gas withdrawn from the head of column 4 is, after heating in 1, recovered via a pipe 21.
  • a production line liquid nitrogen 27 and a liquid oxygen production line 29 are also indicated in Figure 1, a production line liquid nitrogen 27 and a liquid oxygen production line 29.
  • the turbine 9 is braked by an alternator 10 but can also be curbed by other means. Similarly, the turbine wheel 9 can be chocked on the same shaft as that of the pump 7.
  • FIG 4 does not differ from that of figure 1 that in that it comprises an argon column 41 and argon pumps liquid and liquid nitrogen 47, 45.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

Air is separated by cryogenic distillation in at least one column (2) to produce oxygen-rich liquid and nitrogen-rich vapour, heat exchanger (1) cooling the air (11) before it enters the column by heat exchange with an outgoing liquid fraction (23), which vapourises in exchanger (1). Cooling of column (2) is effected by a further feed of compressed fluid (13) which is depressurised in at least one turbine (9), the fluid in the turbine(s) being at least 95 and preferably 100% liquid. Also claimed is installation comprising the heat exchanger, distillation column and turbine.

Description

La présente invention est relative à un procédé et une installation de séparation d'air par distillation cryogénique.The present invention relates to a method and an installation for air separation by cryogenic distillation.

La séparation d'air par voie cryogénique implique l'utilisation d'une génération de froid ou d'une source de froid.Air separation by cryogenic means involves the use of a generation of cold or a source of cold.

Il est connu de détendre avec travail extérieur des gaz sous pression, introduits dans une machine de détente à des températures nettement supérieures à leur point de rosée.It is known to relax with external work of gases under pressure, introduced into an expansion machine at clearly temperatures greater than their dew point.

FR-A-2 335 809 décrit un appareil à une seule turbine qui fournit toutes les frigories nécessaires au procédé. Le gaz détendu dans la turbine peut être l'air ou l'azote moyenne pression. De l'air supressé est liquéfié par échange de chaleur avec de l'oxygène liquide sous pression qui se vaporise.FR-A-2 335 809 describes a device with a single turbine which provides all the frigories necessary for the process. The expanded gas in the turbine can be medium pressure air or nitrogen. Supressed air is liquefied by exchange of heat with pressurized liquid oxygen which vaporizes.

US-A-5 564 290 décrit un procédé dans lequel de l'air pressurisé, condensé par la vaporisation de l'oxygène liquide pompé, se vaporise ensuite dans une turbine afin de produire un débit diphasique.US-A-5,564,290 describes a process in which pressurized air, condensed by the vaporization of the pumped liquid oxygen, then vaporizes in a turbine to produce a two-phase flow.

Il est également connu de tenir en froid un appareil au moins partiellement par biberonnage de liquides cryogéniques dans les colonnes de distillation.It is also known to keep an appliance at least cold partially by spraying cryogenic liquids into the columns of distillation.

Les turbines hydrauliques connues produisent un fluide qui est généralement sous forme liquide.Known hydraulic turbines produce a fluid which is usually in liquid form.

La présente invention a pour but d'améliorer les performances énergétiques des appareils connus.The present invention aims to improve performance energy of known devices.

Selon l'invention, il est prévu un procédé de séparation d'air par distillation cryogénique dans lequel l'air se refroidit dans un échangeur principal et est envoyé à une colonne de distillation d'un appareil comprenant au moins une colonne de distillation où il se sépare en un liquide enrichi en oxygène et une vapeur enrichie en azote, et un débit de liquide pressurisé provenant de l'appareil se vaporise dans l'échangeur principal, les frigories nécessaires au procédé étant générées par détente d'un fluide calorigène dans une ou plusieurs turbines caractérisé en ce que la ou toutes les turbines de l'appareil produisent au refoulement un débit qui est au moins 95 % liquide, notamment 100 % liquide. According to the invention, there is provided a method of air separation by cryogenic distillation in which the air cools in an exchanger main and is sent to a distillation column of an apparatus comprising at least one distillation column where it separates into a liquid enriched in oxygen and nitrogen-enriched vapor, and pressurized liquid flow from the device vaporizes in the main exchanger, the frigories necessary for the process being generated by expansion of a circulating fluid in one or more turbines characterized in that the or all of the turbines the device produces a discharge which is at least 95% liquid, especially 100% liquid.

Selon d'autres aspects de l'invention, il est prévu un procédé dans lequel :

  • le fluide calorigène entre dans la(les) turbine(s) sous forme liquide ou sous une pression au dessus de la pression supercritique.
  • le fluide calorigène entrant dans la(les) turbine(s) provient du bout froid de l'échangeur principal.
  • le fluide calorigène est de l'air ou un fluide provenant de l'appareil de séparation.
  • le liquide pressurisé est enrichi en oxygène, en azote ou en argon.
  • la turbine constitue la seule turbine de l'appareil.
  • deux turbines détendent successivement le même fluide calorigène.
  • l'appareil comprend une double colonne, constituée par une colonne moyenne pression et une colonne basse pression.
  • l'appareil comprend également une colonne argon alimentée par un débit enrichi en argon provenant de la colonne basse pression.
  • on envoie le débit détendu dans la(les) turbine(s) à la colonne moyenne pression et/ou à la colonne basse pression.
According to other aspects of the invention, a method is provided in which:
  • circulating fluid enters the turbine (s) in liquid form or at a pressure above the supercritical pressure.
  • the circulating fluid entering the turbine (s) comes from the cold end of the main exchanger.
  • the circulating fluid is air or a fluid coming from the separation device.
  • the pressurized liquid is enriched with oxygen, nitrogen or argon.
  • the turbine constitutes the only turbine of the device.
  • two turbines successively expand the same circulating fluid.
  • the device comprises a double column, consisting of a medium pressure column and a low pressure column.
  • the apparatus also comprises an argon column supplied with a flow enriched in argon coming from the low pressure column.
  • the expanded flow in the turbine (s) is sent to the medium pressure column and / or to the low pressure column.

Une seule turbine hydraulique permet de tenir en froid sans l'aide d'une turbine qui détend du gaz à une pression en-dessous de la pression supercritique. Cette réduction en investissement est rendue possible par l'amélioration des performances des échangeurs à plaque (ΔT minimal entre 2 °C et 1 °C) d'où de faibles pertes par écart et à cause des rendements améliorés des turbines hydrauliques des dernières générations.A single hydraulic turbine keeps cold without help of a turbine which expands gas to a pressure below the pressure supercritical. This reduction in investment is made possible by improving the performance of plate heat exchangers (minimum ΔT between 2 ° C and 1 ° C) where low spread losses and because of yields improved hydraulic turbines of the latest generations.

Selon l'invention, il est également prévu une installation de séparation d'air par distillation cryogénique comprenant :

  • au moins une colonne de distillation,
  • un échangeur de chaleur,
  • des moyens pour envoyer de l'air à l'échangeur de chaleur et de l'échangeur de chaleur à une colonne de distillation,
  • des moyens pour soutirer un liquide d'une colonne de distillation et pour le pressuriser,
  • des moyens pour envoyer le liquide pressurisé à l'échangeur de chaleur,
  • une ou plusieurs turbines de détente, alimentée(s) par un fluide calorigène
    •    caractérisée en ce que la seule (ou les seules) turbine(s) de l'installation sont capables de produire au refoulement un débit qui est au moins 95 % liquide.According to the invention, an air separation installation is also provided by cryogenic distillation comprising:
  • at least one distillation column,
  • a heat exchanger,
  • means for sending air to the heat exchanger and from the heat exchanger to a distillation column,
  • means for withdrawing a liquid from a distillation column and for pressurizing it,
  • means for sending the pressurized liquid to the heat exchanger,
  • one or more expansion turbines, supplied with circulating fluid
    • characterized in that the only (or only) turbine (s) of the installation are capable of producing a discharge which is at least 95% liquid.

    L'invention se révèle particulièrement avantageuse dans le cas où il y a une production d'argon, car elle améliore le taux de reflux à l'intérieur de la colonne principale.The invention proves to be particularly advantageous in the case where there is argon production because it improves the reflux rate inside the main column.

    Dans le cas où le fluide calorigène destiné à la turbine hydraulique soit du bout froid de l'échangeur, ceci permet une réduction des coûts de fabrication de l'échangeur.In the event that the circulating fluid intended for the hydraulic turbine is from the cold end of the exchanger, this reduces the costs of manufacture of the exchanger.

    Des exemples de mise en oeuvre vont maintenant être décrits en regard des dessins annexés, sur lesquels :

  • - les figures 1 à 4 représentent respectivement, de façon schématique, quatre modes de réalisation selon l'invention.
    • Examples of implementation will now be described with reference to the appended drawings, in which:
  • - Figures 1 to 4 show respectively, schematically, four embodiments according to the invention.

    • L'installation de production d'oxygène gazeux sous pression représentée sur la figure 1 comprend essentiellement une ligne d'échange thermique 1 destinée à refroidir l'air à traiter par échange de chaleur indirect à contre-courant avec des produits froid; un appareil de distillation d'air 2 du type à double colonne, constitué essentiellement d'une colonne moyenne pression 4 surmontée d'une colonne basse pression 3, avec un vaporiseur-condenseur 5 mettant en relation d'échange thermique indirect la vapeur de tête (azote) de la colonne 4 et le liquide de cuve (oxygène) de la colonne 3, un sous-refroidisseur 6, une turbine de détente d'air 9 et une pompe d'oxygène liquide 7.The installation for producing gaseous oxygen under pressure shown in Figure 1 essentially includes an exchange line thermal 1 intended to cool the air to be treated by indirect heat exchange at counter current with cold products; an air distillation apparatus 2 of the type double column, consisting essentially of a medium pressure column 4 surmounted by a low pressure column 3, with a vaporizer-condenser 5 relating the indirect heat exchange to the overhead vapor (nitrogen) of column 4 and the tank liquid (oxygen) of column 3, a sub-cooler 6, an air expansion turbine 9 and a liquid oxygen pump 7.

    De l'air à traiter 11 à entre 5 et 7 bars entre dans la ligne d'échange 1 et est refroidi jusqu'à environ sa température de rosée. Cet air entre alors dans la colonne moyenne pression 5 où il est séparé en un « liquide riche » (air enrichi en oxygène) et en azote. Le liquide riche 31 et l'azote liquide 33 soutiré en tête de la colonne 4 sont sous-refroidis dans le sous-refroidisseur 6 par l'azote impur basse pression 25 produit en tête de la colonne 3 puis, après détente dans des vannes de détente respectivement, alimentent cette colonne basse pression 3. Après réchauffement en 6 puis en 1 l'azote impur basse pression, à la température ambiante peut servir à régénérer un appareil d'épuration.Air to be treated 11 to between 5 and 7 bars enters the exchange line 1 and is cooled to approximately its dew point temperature. This air then enters the medium pressure column 5 where it is separated into a "rich liquid" (air enriched in oxygen) and nitrogen. The rich liquid 31 and the liquid nitrogen 33 withdrawn at the head of column 4 are sub-cooled in sub-cooler 6 by low pressure impure nitrogen 25 produced at the head of column 3 then, after expansion in expansion valves respectively, feed this column low pressure 3. After heating in 6 then in 1 the impure nitrogen low pressure, at room temperature can be used to regenerate a device of purification.

    Le reste de l'air 13 (constituant 30 % environ de l'air) est surpressé à entre 7 et 100 bars et se refroidit en traversant toute la ligne d'échange 1, d'où ils sort soit sous forme liquide soit sous forme de gaz dense si sa pression dépasse 36 bars.The rest of the air 13 (constituting approximately 30% of the air) is overpressed to between 7 and 100 bars and cools across the entire exchange line 1, hence they come out either in liquid form or in the form of dense gas if its pressure exceeds 36 bars.

    Cet air 13 est détendu à la moyenne pression dans la turbine 9 afin de former un débit liquide.This air 13 is expanded at medium pressure in the turbine 9 in order to form a liquid flow.

    Une partie du liquide 19 est envoyée à la colonne moyenne pression 4 et le reste 17 est détendu dans une vanne avant d'être envoyé à la colonne basse pression 3.Part of the liquid 19 is sent to the medium pressure column 4 and the rest 17 is relaxed in a valve before being sent to the column low pressure 3.

    L'oxygène de production est soutiré sous forme liquide de la cuve de la colonne basse pression 3, amené en 7 à la pression de production (entre 1,8 et 100 bars), vaporisé par échange de chaleur avec l'air 13, réchauffé jusqu'à la température ambiante et récupéré sous forme d'oxygène gazeux via une conduite 23.The production oxygen is drawn off in liquid form from the tank of the low pressure column 3, brought in 7 to the production pressure (between 1.8 and 100 bars), vaporized by heat exchange with air 13, heated to the room temperature and recovered in the form of gaseous oxygen via a driving 23.

    Par ailleurs de l'azote gazeux soutiré de la tête de la colonne 4 est, après réchauffement en 1, récupéré via une conduite 21.Furthermore, nitrogen gas withdrawn from the head of column 4 is, after heating in 1, recovered via a pipe 21.

    On a également indiqué sur la figure 1, une conduite de production d'azote liquide 27 et une conduite de production d'oxygène liquide 29.Also indicated in Figure 1, a production line liquid nitrogen 27 and a liquid oxygen production line 29.

    La turbine 9 est freinée par un alternateur 10 mais peut également être freinée par d'autres moyens. De même, la roue de la turbine 9 peut être calée sur le même arbre que celui de la pompe 7.The turbine 9 is braked by an alternator 10 but can also be curbed by other means. Similarly, the turbine wheel 9 can be chocked on the same shaft as that of the pump 7.

    L'installation représentée sur la figure 2 ne diffère de celle de la figure 1 que par le fait que le fluide calorigène alimentant la turbine 9 est de l'azote 21 soutiré de la colonne 4, comprimé par le compresseur 35 à entre 7 et 100 bars après réchauffement à la température ambiante et refroidi en 1 pour se retrouver liquide ou sous pression supercritique à l'entrée de la turbine 9. Le liquide ainsi produit après détente dans la turbine 9 est envoyé en tête de la colonne moyenne pression 4.The installation shown in Figure 2 does not differ from that of Figure 1 only by the fact that the circulating fluid supplying the turbine 9 is nitrogen 21 withdrawn from column 4, compressed by compressor 35 to between 7 and 100 bars after warming up to room temperature and cooled in 1 to find liquid or under supercritical pressure at the inlet of the turbine 9. The liquid thus produced after expansion in the turbine 9 is sent to the top of the medium pressure column 4.

    Ceci permet de produire un débit d'azote 37 à pression élevée.This makes it possible to produce a flow of nitrogen 37 at high pressure.

    L'installation représentée sur la figure 3 ne diffère de celle de la figure 1 qu'en ce qu'elle comprend deux turbines hydrauliques 9, 39. La turbine 39 remplace la vanne sur la ligne 15 et est alimentée par du liquide provenant du refoulement de la turbine 9.The installation shown in Figure 3 does not differ from that of Figure 1 that in that it comprises two hydraulic turbines 9, 39. The turbine 39 replaces the valve on line 15 and is supplied with liquid from the turbine discharge 9.

    L'installation représentée sur la figure 4 ne diffère de celle de la figure 1 qu'en ce qu'elle comprend une colonne argon 41 et des pompes à argon liquide et à azote liquide 47, 45.The installation shown in figure 4 does not differ from that of figure 1 that in that it comprises an argon column 41 and argon pumps liquid and liquid nitrogen 47, 45.

    Pour simplifier le dessin, la ligne de liquide riche servant à refroidir le condenseur de tête de la colonne argon n'est pas montrée.To simplify the drawing, the line of rich liquid used to cool the argon column condenser is not shown.

    Il est également envisageable de prévoir deux turbines hydrauliques pour fournir les frigories, dont une détend un débit d'air et l'autre le débit d'azote de cycle.It is also possible to envisage two hydraulic turbines to supply frigories, one of which expands an air flow and the other the flow cycle nitrogen.

    Claims (12)

    Procédé de séparation d'air par distillation cryogénique dans lequel l'air se refroidit dans un échangeur principal (1) et est envoyé à une colonne de distillation d'un appareil comprenant au moins une colonne de distillation où il se sépare en un liquide enrichi en oxygène et une vapeur enrichie en azote, et un débit de liquide pressurisé provenant de l'appareil se vaporise dans l'échangeur principal, des frigories nécessaires au procédé étant générées par détente d'un fluide calorigène dans une ou plusieurs turbine (9, 39) caractérisé en ce que la ou toutes les turbines de l'appareil produisent au refoulement un débit qui est au moins 95 % liquide, notamment 100 % liquide.Method of air separation by cryogenic distillation in which the air cools in a main exchanger (1) and is sent to a column of distillation of an apparatus comprising at least one distillation column where it separates into a liquid enriched in oxygen and a vapor enriched in nitrogen, and a flow of pressurized liquid from the device vaporizes in the main exchanger, frigories necessary for the process being generated by expansion of circulating fluid in one or more turbines (9, 39) characterized in that the or all the turbines of the apparatus produce at the discharge a flow rate which is at least 95% liquid, in particular 100% liquid. Procédé selon la revendication 1 dans lequel le fluide calorigène entre dans la(les) turbine(s) sous forme liquide ou sous une pression au dessus de la pression supercritique.The method of claim 1 wherein the circulating fluid enters the turbine (s) in liquid form or under pressure at above the supercritical pressure. Procédé selon la revendication 1 ou 2 dans lequel le fluide calorigène entrant dans la(les) turbine(s) provient du bout froid de l'échangeur principal (1).The method of claim 1 or 2 wherein the fluid circulating fluid entering the turbine (s) comes from the cold end of the exchanger main (1). Procédé selon l'une des revendications précédentes dans lequel le fluide calorigène est de l'air ou un fluide provenant de l'appareil de séparation.Method according to one of the preceding claims, in which the circulating fluid is air or a fluid from the separation device. Procédé selon l'une des revendications précédentes dans lequel le liquide pressurisé est enrichi en oxygène, en azote ou en argon.Method according to one of the preceding claims, in which the pressurized liquid is enriched with oxygen, nitrogen or argon. Procédé selon l'une des revendications précédentes dans lequel la turbine (9) constitue la seule turbine de l'appareil.Method according to one of the preceding claims, in which the turbine (9) constitutes the only turbine of the device. Procédé selon l'une des revendications 1 à 5 dans lequel deux turbines détendent successivement le même fluide calorigène, ce fluide calorigène étant l'air.Method according to one of claims 1 to 5 wherein two turbines successively expand the same circulating fluid, this fluid circulating being air. Procédé selon l'une des revendications précédentes dans lequel l'apareil comprend une double colonne, constituée par une colonne moyenne pression et une colonne basse pression.Method according to one of the preceding claims, in which the device includes a double column, consisting of a medium column pressure and a low pressure column. Procédé selon la revendication 8 dans lequel l'appareil comprend également une colonne argon alimentée par un débit enrichi en argon provenant de la colonne basse pression. The method of claim 8 wherein the apparatus comprises also an argon column fed by a flow enriched in argon from the low pressure column. Procédé selon la revendication 8 ou 9 dans lequel on envoie le débit détendu dans la(les) turbine(s) à la colonne moyenne pression et/ou à la colonne basse pression.Method according to claim 8 or 9 in which the expanded flow in the turbine (s) at the medium pressure column and / or at the low pressure column. Installation de séparation d'air par distillation cryogénique comprenant : au moins une colonne de distillation (2), un échangeur de chaleur (1), des moyens pour envoyer de l'air à l'échangeur de chaleur et de l'échangeur de chaleur à une colonne de distillation, des moyens pour soutirer un liquide d'une colonne de distillation et pour le pressuriser, des moyens pour envoyer le liquide pressurisé à l'échangeur de chaleur, une ou plusieurs turbines de détente, alimentée(s) par un fluide calorigène    caractérisée en ce que la seule (ou les seules) turbine(s) de l'installation sont capables de produire au refoulement un débit qui est au moins 95 % liquide.Installation of air separation by cryogenic distillation comprising: at least one distillation column (2), a heat exchanger (1), means for sending air to the heat exchanger and from the heat exchanger to a distillation column, means for withdrawing a liquid from a distillation column and for pressurizing it, means for sending the pressurized liquid to the heat exchanger, one or more expansion turbines, supplied with circulating fluid characterized in that the only (or only) turbine (s) of the installation are capable of producing a discharge which is at least 95% liquid. Installation selon la revendication 11 comprenant une double colonne de distillation et éventuellement une colonne argon.Installation according to claim 11 comprising a double distillation column and optionally an argon column.
    EP98400803A 1997-04-03 1998-04-03 Process and plant for air separation by cryogenic distillation Withdrawn EP0869322A1 (en)

    Applications Claiming Priority (2)

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    FR9704083A FR2761762B1 (en) 1997-04-03 1997-04-03 METHOD AND INSTALLATION FOR AIR SEPARATION BY CRYOGENIC DISTILLATION

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    EP3620739A1 (en) * 2018-09-05 2020-03-11 Linde Aktiengesellschaft Method for the low-temperature decomposition of air and air separation plant

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    FR2848650A1 (en) * 2002-12-13 2004-06-18 Air Liquide Cryogenic fluid expansion procedure and apparatus, for use in distillation separation process, uses two expansion units to produce liquid and diphasic flows
    EP1972875A1 (en) * 2007-03-23 2008-09-24 L'AIR LIQUIDE, S.A. pour l'étude et l'exploitation des procédés Georges Claude Process and apparatus for the separation of air by cryogenic distillation

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    EP3620739A1 (en) * 2018-09-05 2020-03-11 Linde Aktiengesellschaft Method for the low-temperature decomposition of air and air separation plant
    WO2020048634A1 (en) 2018-09-05 2020-03-12 Linde Aktiengesellschaft Method for the low-temperature separation of air and air separation plant

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    CZ98798A3 (en) 1998-12-16
    PL325664A1 (en) 1998-10-12
    SG72799A1 (en) 2000-05-23
    AU723241B2 (en) 2000-08-24
    AR012326A1 (en) 2000-10-18
    US5901577A (en) 1999-05-11
    CA2234435A1 (en) 1998-10-03
    AU5950398A (en) 1998-10-08
    TW364943B (en) 1999-07-21
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    JPH1172286A (en) 1999-03-16
    BR9801005A (en) 1999-10-26

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