DE2133465A1 - Liquid nitrogen prodn - by single-column fractional distillation of air at 6 to 9 bar pressure - Google Patents

Liquid nitrogen prodn - by single-column fractional distillation of air at 6 to 9 bar pressure

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Publication number
DE2133465A1
DE2133465A1 DE19712133465 DE2133465A DE2133465A1 DE 2133465 A1 DE2133465 A1 DE 2133465A1 DE 19712133465 DE19712133465 DE 19712133465 DE 2133465 A DE2133465 A DE 2133465A DE 2133465 A1 DE2133465 A1 DE 2133465A1
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Prior art keywords
column
liquid
nitrogen
air
line
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DE19712133465
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German (de)
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Otto Dipl-Ing Kaiser
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Linde GmbH
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Linde GmbH
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Priority to DE19712133465 priority Critical patent/DE2133465A1/en
Publication of DE2133465A1 publication Critical patent/DE2133465A1/en
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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
    • F25J3/04472—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 cold from cryogenic liquids produced within the air fractionation unit and stored in internal or intermediate storages
    • F25J3/04478—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 cold from cryogenic liquids produced within the air fractionation unit and stored in internal or intermediate storages for controlling purposes, e.g. start-up or back-up procedures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/0423—Subcooling of liquid process streams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04278—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using external refrigeration units, e.g. closed mechanical or regenerative refrigeration units
    • 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
    • F25J3/04763—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.
    • F25J3/04884—Arrangement of reboiler-condensers
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/72—Refluxing the column with at least a part of the totally condensed overhead gas
    • 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
    • F25J2235/42—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being 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
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being 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
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/20—Boiler-condenser with multiple exchanger cores in parallel or with multiple re-boiling or condensing streams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/02—Internal refrigeration with liquid vaporising loop
    • 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
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration

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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

Air cooled to dew point by heat exchange in the sump of the fractionating column is fed to the column at 6-9 bar press. at a point in the lower half of the column. A liquid stream contg. 15-20 mol % O2 is withdrawn from a point in the upper half of the column and used to deep-cool the liquid product N2 and the liquid O2 fraction withdrawn from the column sump. Gaseous N2 is taken off at the head of the column and liquefied in a cryogenerator, about 60% of the liquid N2 being returned to the column head as reflux liquid. The deep-cooled liquid O2 fraction is flashed off and vaporised in a heat exchanger in the column head, to provide additional refrigeration and/or collected as a product stream.

Description

Kennwort: Kryo;enerator Verfahren zum Gewinnen von flüssigem Stickstoff Die Erfindung betrifft ein Verfahren zun Gewinnen von flüssigem Stickstoff durch einstufige Rektifikatlcn von Luft in einer Zerlegungskolonne, bei dem als Kältequelle ein Kryogenerator (Gaskältemaschine) dient.Password: Cryo; enerator Process for the production of liquid nitrogen The invention relates to a method for recovering liquid nitrogen by single-stage rectifications of air in a separation column, in which as a source of cold a cryogenerator (gas refrigerator) is used.

Als Verfahren zum Gewinnen von flüssigem Stickstoff mittels eines Kryogenerators bietet sich die Möglichkeit an, zunächst gasförmigen Stickstoff durch Rektifikatton von Luft zu gewinnen und diesen dann mit dem Kryogenerator zu verflüssigen.As a method for recovering liquid nitrogen by means of a The cryogenerator offers the option of initially carrying out gaseous nitrogen Obtaining rectified clay from air and then liquefying it with the cryogenerator.

Verwendet man zur Luftzerlegung das aufwendige Doppelsäulen-Verfahren, darum fällt der Stickstoff bei nur etwa 1 bar an, sodaß der Kryogenerator bei der entsprechend tiefen Verflüs sigungstemperatur nicht im gUnstigsten Bereich arbeitet. Beim Einsäulenverfahren bietet sich ein Stickstoffdruck von etwa 4 bar an. Der nachgeschaltete Kryogenerator arbeitet dann bei günstigerer Verflüssigungstemperatur. Bei der einstufigen Rektifikation ist jedoch die Luftausbeute schlecht.If the complex double-column process is used for air separation, therefore the nitrogen is only produced at about 1 bar, so that the cryogenerator works at the correspondingly low condensing temperature is not working in the most favorable range. In the case of the single-column method, a nitrogen pressure of around 4 bar is recommended. The downstream The cryogenerator then works at a more favorable condensing temperature. With the single-stage However, in rectification, the air yield is poor.

Es ist ferner ein Verfahren bekannt, (Köhler, J.W.L., u. J.A method is also known (Köhler, J.W.L., and J.

van der Stern A small liquid nitrogen plant, using a gas refrigerating machine. Comptes rendus du IX. Congrès Int. du Froid, Paris 1955, Bd. I S. 1057 - 1063) bei dem die Luft einstufig bei atmosphärischem Druck rektifiziert, und der Kolonnenkopf durch einen Kryogenerator gekühlt wird. Der Vorteil dieses Verfahrens besteht darin, daß die Luft nicht verdichtet zu werden braucht. Nachteilig ist auch hier, daß der Krygenerator nicht im günstigsten Bereich arbeitet. Zudem erlaubt die Ausfriermethode für das Wasser und Kohlendioxid der Luft nur kleinere Durchsätze.van der Stern A small liquid nitrogen plant, using a gas refrigerating machine. Comptes rendus du IX. Congrès Int. du Froid, Paris 1955, vol. I p. 1057 - 1063) in which the air is rectified in one stage at atmospheric pressure, and the The top of the column is cooled by a cryogenerator. The advantage of this procedure is that the air does not need to be compressed. Is also disadvantageous here that the crygenerator is not working in the most favorable range. Also allowed the freezing method for the water and carbon dioxide in the air has only smaller throughputs.

Der Erfindung liegt die Aufgabe zugrunde. ein Verfahren zum Gewinnen von flüssigem Stickstoff zu schaffen, bei dem der Kryogenerator in einem günstigen Bereich arbeitet, d.h. bei einer höheren kühltemperatur. Andererseits soll die Rektifikation mit guter Luftausbeute arbeiten.The invention is based on the object. a method of winning of liquid nitrogen to create, in which the cryogenerator in a cheap Area works, i.e. at a higher cooling temperature. On the other hand, the rectification should work with a good air yield.

Gefunden wurde ein Verfahren zum Gewinnen von flüssigem Sticlcstoff durch einstufige Rektifikation vc,r. Luft; in einer Kolonne, deren Kopf durch einen Kryogenerator gekühlt wird. Erfindungsgemäß wird din Rektifikation bei einen Iruck von 6 bis 9 bar durchgeführt Das erfindungsgemäße Verfahren läßt sich besonders vorteilhaft gestalten, wenn aus der Zerlegungskolonne Flüssigkeit mit einem Sauerstoffgehalt von etwa 15 bis 20 Mol.- Prozent entnommen wird.A method for recovering liquid nitrogen has been found by single-stage rectification vc, r. Air; in a column, the head of which by a Cryogenerator is cooled. According to the invention, the rectification is carried out in the event of a pressure carried out from 6 to 9 bar The process according to the invention is particularly useful Make it advantageous if from the decomposition column liquid with an oxygen content from about 15 to 20 mole percent is withdrawn.

Diese Zwischenfraktion wird zum Tiefkühlen des flüssigen Produktstickstoffes und anschließend zum Tiefkühlen der flüssigen Sauerstofffraktion verwendete Die tiefgekühlte Sauerstofffraktion kann entspannt und am Kolonnenkopf verdampft werden. Sie kann aber auch als Produktstrom in einen Speicher geleitet werden.This intermediate fraction is used to freeze the liquid product nitrogen and then used die to freeze the liquid oxygen fraction Frozen oxygen fraction can be expanded and evaporated at the top of the column. However, it can also be fed into a storage facility as a product stream.

Ba1 dieser vor@ellhaften Verfahrensausführung läßt sich der Rektifikations@ruck bei guter Luftausbeute bis auf etwa 9 bar hinauftreiben. Der zugleich benötigte höhere Luftdruck macht sich durch die höhere Kälteleistung und den besseren Wirkung'sgrad der Kältemaschine bezahlt. Die Verflüsslgungsleistung ist etwa 40% größer als bei dem Rektifikationsdruck von 1,5 bar.The rectification jerk can be reduced to this preliminary process execution if the air yield is good, push it up to around 9 bar. The one needed at the same time The higher air pressure is due to the higher cooling capacity and the better degree of effectiveness the chiller paid. The condensing capacity is around 40% greater than that of the rectification pressure of 1.5 bar.

Der elektrische Leistungsbedarf ist nicht hoch.Wird flüssiger Stickstoff allein erzeugt, beträgt er 0s89 kW je Nm3 Flüssigkeit. Werden flüssiger Stickstoff und flüssiger Sauerstoff erzeugt, beträgt er 0,97 kW Je Nm3 Flüssigkeit. Hierbei ist die gesamte Leistung berücksichtigt, also der Energieaufwand für die Luftverdiehtung, den Kryogenerator, die Pumpe und den Erhitzer. Der angegebene Leistungsbedarf ist auf @iefkalte Flüssigkeit bezogen, die bei 1 bar siedet.The electrical power requirement is not high. It becomes liquid nitrogen generated alone, it amounts to 0s89 kW per Nm3 liquid. Become liquid nitrogen and liquid oxygen is generated, it is 0.97 kW per Nm3 liquid. Here the total power is taken into account, i.e. the energy expenditure for air compression, the cryogenerator, the pump and the heater. The specified power requirement is based on a cryogenic liquid that boils at 1 bar.

Zwei Ausführungsbeispeile der Erfindung sollen anhand der belgefügten Zeichnungen erläutert werden.Two exemplary embodiments of the invention should be based on the illustrated Drawings are explained.

Es zeigen: Fig. 1 das Verfahrensschema einer Anlage zum Gewinnen von flüssigem Stickstoff Fig. 2 das Verf.iarensschema einor Anlage zum Gewinnen von flüssigem Stickstoff und flüssigem Sauerstoff.The figures show: FIG. 1 the process diagram of a plant for extracting liquid nitrogen liquid nitrogen and liquid oxygen.

Bei dem in Fig. 1 dargestellten Ausführungsbeispiel wird atmosphärische Luft durch Leitung 1 vom Verdichter 2 angesaugt und auf einen Druck von <) bar verdichtet. Anschl@eßend wird die Luft in den umschaltbaren Adsorbern 3a, 3b von Wasser und Kohlendioxid befreit. Die gereinigte Luft, beispielsweise 100 Nm3/h, gelangt durch Leitung 4 in den Wärmeübertrager 5 und die Sumpfschlange 6, wo sie nahezu au Tautemperatur abgekühlt wird. Danach wird sie in die Kolonne 7 geleitet, die e erfindungagemäß unter einem Druck von 9 bar steht.In the embodiment shown in Fig. 1 is atmospheric Air sucked in through line 1 from the compressor 2 and brought to a pressure of <) bar condensed. Subsequently, the air in the switchable adsorbers 3a, 3b of Freed water and carbon dioxide. The cleaned air, for example 100 Nm3 / h, passes through line 4 in the heat exchanger 5 and the sump coil 6, where it is cooled to almost the dew temperature. It is then passed into column 7, According to the invention, the e is under a pressure of 9 bar.

Aus dem Kolonnenkopf wird durch Leitung 8 gasförmiger Stickstoff und aus dem Kolonnensumpf durch Leitung 9 eine flUssige Sauerstofffraktion abgezogen. Die Sauerstoffraktion setzt sich zusammen aus etwa 80 Mol% Sauerstoff, 3 Mol% Argon und 17 Mol% Stickstoff. Durch Leitung 10 wird ferner aus der Kolonne 7 eine flüssige Zwischenfralction abgezogen, die zu etwa 20 Mol% aus Sauerstoff, 2 Mol% aus Argon und 78 Mol% aus Stickstoff besteht.From the top of the column is gaseous nitrogen and through line 8 A liquid oxygen fraction is drawn off from the bottom of the column through line 9. The oxygen fraction is composed of about 80 mol% oxygen and 3 mol% argon and 17 mole percent nitrogen. Furthermore, the column 7 becomes a liquid through line 10 Intermediate fraction subtracted, about 20 mol% of oxygen, 2 mol% of argon and 78 mole percent consists of nitrogen.

Die vom Kolonnensumpf durch Leitung 9 abgezogene Sauerstoffraktion, 22 Nm3/h, wird im Sauerstoff-Tiefkühler 11 tiefgekühlt und im Adsorber 12 von Kohlenwasserstoffen, insbesondere Azetylen, befreit. Sie wird dalln im Drosselventil 13 auf l,'r bar cntspa@nt und in der Kopfschlange 14 verdampft und trägt so zum Kühlon des Kolonnenkopfes bei. Die verdampfte Sauerstofffraktion gelan@t durch Leitung 15 in den Sauerstoff-Tiefkühler 11 und anschlies-@end in den Wärmeübertrager 5, in dem sie auf Umgebungstemperatur angewärmt wird.The oxygen fraction withdrawn from the column bottom through line 9, 22 Nm3 / h, is frozen in the oxygen freezer 11 and hydrocarbons in the adsorber 12, especially acetylene, exempted. It is then in the throttle valve 13 to 1.5 bar cntspa @ nt and evaporates in the head coil 14 and thus contributes to the cooling of the column head at. The vaporized oxygen fraction reaches the oxygen freezer through line 15 11 and then in the heat exchanger 5, in which it is brought to ambient temperature is warmed up.

Der aus dem Kolonnenkopf durch Leitung 8 abgezogene gasförmige Stickstoff, 164 Nm3/h, wird im Kryogenerator 16 verflüssigt, und die Flüssigkeit durch Leitung 17 in den Abscheider 18 geleitet.The gaseous nitrogen withdrawn from the top of the column through line 8, 164 Nm3 / h, is liquefied in the cryogenerator 16, and the liquid through conduit 17 passed into the separator 18.

In der Leitung 17 mitgerissenes Stickstoffgas wird vom Abscheider 18 durch Leitung 19 in die Leitung 8 zurückgegeben, wahrend der verflüssigte Stickstoff durch Leitung 20 aus dem Abscheider 18 abgezogen wird. Ein Teilstrom, 102 Nm3/h, des verflüssigten Stickstoffes gelangt durch Leitung 21 zur Pumpe 22, wird auf den Kolonnenkopf gefördert und dient als Rücklaufflüssigkeit für die Rektiftkation. Der Rste, 62 Nm3/h, ist das Stickstoffprodukt. Es strömt durch Leitung 25 zum Stickstoff-Tiefkühler 26, wo es tiefgekUhlt wird. Anschließend wird das Stickstoffprodukt in dem Regelventil 27 a auf den Druck des Tarks entspannt und diesem durch das Absperrventil 27b zugeleitet.Nitrogen gas entrained in line 17 is removed from the separator 18 returned through line 19 into line 8, while the liquefied nitrogen is withdrawn from the separator 18 through line 20. A partial flow, 102 Nm3 / h, the liquefied nitrogen passes through line 21 to pump 22, is on the The top of the column is promoted and serves as a reflux liquid for the rectification cation. The remainder, 62 Nm3 / h, is the nitrogen product. It flows through line 25 to the nitrogen freezer 26, where it is frozen. Then the nitrogen product is in the control valve 27 a relaxed to the pressure of the tark and fed to it through the shut-off valve 27b.

Die Stickstoffreinheit wird mit der Rücklaufmenge geregelt. Dies Geschieht durch Betätigen des Regelventiles 23 in der Beipaßleitung 24.The nitrogen purity is regulated with the return volume. This happens by actuating the control valve 23 in the bypass line 24.

Um beim Anfaliren rasch reinen Stickstoff zu erhalten, wird der Rücklauf im Oberteil der Kolonne durch öffnen von Ventil 31 verstärkt. Die entnommene Flüssigkeit gelangt durch die Anfahrleitung 30 ins Preie. Eventuell unreines Stickstoffprodukt wird durch Leitung 28 ins Freie abgeführt, indem man Ventil 27b schließt und Ventil 29 öffnet.In order to obtain pure nitrogen quickly when starting up, the return flow is used Reinforced in the upper part of the column by opening valve 31. The removed liquid comes through the starting line 30 into the price. Possibly impure nitrogen product is discharged to the outside through line 28 by closing valve 27b and valve 29 opens.

Die durch Leitung 10 abgezogene flüssige Zwischenfraktion, 16 Nm3/h, wird im Drosselventil 32 auf 1,5 bar entspannt und verdampft im Stickstoff-Tiefkühler 26 und Sauerstoff-Tiefkühler 11.The liquid intermediate fraction withdrawn through line 10, 16 Nm3 / h, is expanded to 1.5 bar in the throttle valve 32 and evaporates in the nitrogen freezer 26 and oxygen freezer 11.

Sie wird dann im Wärmeübertrager 5 auf Umgebungstemperatur angewärmt, im Erhitzer 40 aufgeheizt und dient als Regeneriergas flir die umschaltbaren Adsorber 3a, 3b. Durch Leitung 33 verläßt sie die Anlage. Beim Umschalten der -Adsorber 3a und Db ist das Ventil 35 geöffnet, sodaß das Regeneriergas durch die Beipaßleitung 34 abströmen kann.It is then heated to ambient temperature in the heat exchanger 5, heated in the heater 40 and serves as regeneration gas for the switchable adsorber 3a, 3b. It leaves the system through line 33. When switching the adsorber 3a and Db the valve 35 is open, so that the regeneration gas through the bypass line 34 can flow off.

Bei dem in Fig. 2 dar@estellten Verfahren wird nicht nur flüssiger Stickstoff sondern auch flüssiger Sauerstoff gewonnen.In the case of the method shown in FIG. 2, not only does it become more fluid Nitrogen but also liquid oxygen is obtained.

Dazu muß die Rektifikation im Untertell der Kolonne verbessert werden. Dies geschieht durch die höhere Verdichtung der Luft auf 24 bar, scdaß sie sich in der Sumpfschlange 6 verflüssigt.To this end, the rectification in the lower part of the column must be improved. This is done by the higher compression of the air to 24 bar, scdaß it liquefied in the swamp snake 6.

Im übrigen sird die Verfahren nach Fig. 1 und Fig. 2 sehr Shnlich, es wurden deshalb b die gleichen Bezugszeichen für gleiche Anlagenteile verwendet. aegenüber dem Verfahren nach Fig. J entfallen das Drosselventil )3 die Kopfschlange 11 und die Leitung 15. Die Beschreibung wird auf die von dem Verfahren nach Fig. 1 abweichenden Verfahrensmerkmale beschränkt.Otherwise, the methods according to Fig. 1 and Fig. 2 are very similar, The same reference numerals have therefore been used for the same parts of the plant. Compared to the method according to FIG. J, the throttle valve 3 and the head coil are omitted 11 and line 15. The description is based on that of the method according to FIG. 1 restricted procedural features.

Die atmosphärische Luft wird durch Leitung 1 vom Verdichter 2 angesaugt und auf 24 bar verdichtet. Sie gelangt durch die umschaltbaren Adsorber 3a, 3b, Leitung 4 Wärmeübertrager 5 und die Sumpfschlange 6 zum Drosselventil 36, wo sie in flüssigem Zustand auf den Rektifikationsdruck von 9 bar entspannt wird.The atmospheric air is sucked in by the compressor 2 through line 1 and compressed to 24 bar. It passes through the switchable adsorbers 3a, 3b, Line 4 heat exchanger 5 and the sump coil 6 to the throttle valve 36, where they is expanded in the liquid state to the rectification pressure of 9 bar.

In der Kolonne 7 werden beispielsweise 304 Nm3/h zerlegt. Reiner gasförmiger Stickstoff wird durch Leitung 8 aus dem Kolonnenkopf, flüssiger .Sauerstoff durch Leitung 9 aus dem Kolonnensumpf abgezogen. Durch Leitung 10 wird ferner aus der Kolonne 7 eine flüssige Zwischenfraktion entnommen, die zu etwa 15 Mole aus Sauerstoff, 4,6 Mol% aus Argon und 80,4 Mol% aus Stickstoff besteht.In the column 7, for example, 304 Nm3 / h are broken down. Purely gaseous Nitrogen is through line 8 from the top of the column, liquid. Oxygen through Line 9 withdrawn from the column bottom. Through line 10 is also from the Column 7 removed a liquid intermediate fraction, which to about 15 moles of oxygen, 4.6 mole percent argon and 80.4 mole percent nitrogen.

Der aus dem Kolonnensumpr durch Leitung 9 abgezogene flUssige Sauerstoff, 55,6 Nm3/h, wird im Sauerstoff-Tiefkühler 11 tiefgekUhlt und im Adsorber 12 von Kohlenwasserstoffen, insbesondere Azetylen, befreit. Im Regelventil 37a wird er dann auf den Druck des Sauerstofftanks entspannt und diesem durch das Absperrventil 37 b zugeleitet. Die Reinheit des Produktsauerstoffes beträgt 99,7%.The liquid oxygen withdrawn from the column volume through line 9, 55.6 Nm3 / h, is frozen in the oxygen freezer 11 and in the adsorber 12 of Hydrocarbons, especially acetylene, freed. In the control valve 37a he is then relaxed to the pressure of the oxygen tank and this through the shut-off valve 37 b forwarded. The purity of the product oxygen is 99.7%.

Der aus dem Kolonnenkopf durch Leitung 8 abgezo,gene gasförmige Stickstoff wird genau so behandelt wie i>ei dem Verfahren nach Fig. 1. Nach Entspannung im Regelventil 27a gelangen 192,8 Nm3/h flüssiger Stickstoff in den stiekstofftant. Eventuell unreines Sauerstoffprodukt wird durch Leitung 33 ins Freie abgeführt, indem man Ventil 37b schließt und Ventil 39 öffnet.The gaseous nitrogen withdrawn from the top of the column through line 8 is treated exactly as i> ei the method according to Fig. 1. After relaxation 192.8 Nm3 / h of liquid nitrogen enter the fuel tank in the control valve 27a. Any impure oxygen product is discharged into the open through line 33, by closing valve 37b and opening valve 39.

Auch die durch Leitung 10 von der Rektifizierkolonne abgezogene flüssige Zwischenfraktion 55,6 Nm)/h wird genauso behandelt wie im Verfahren gemäß Fig. 1.Also the liquid withdrawn from the rectification column through line 10 Intermediate fraction 55.6 Nm) / h is treated in the same way as in the method according to FIG. 1.

Die beiden Verfahren nach Fig. 1 und 2 @assen sich auch in einer einzigen Anlage verwirklichen. Bei gefülltem Sauerstofftank kann dann die Produlction von Flüssigsauerstoff eingestellt werden.The two methods according to FIGS. 1 and 2 can also be used in a single one Realize the plant. When the oxygen tank is full, the production of Liquid oxygen can be adjusted.

Claims (1)

A N S P R Ü C H E EXPECTATIONS Verfahren zum Gewinnen von flüssigem Stickstoff durch einstufige Rektifikation von Luft in einer Kolonue, deren Kopf durch einen Kryogenerator gekühlt wird, dadurch gekennzeichnet, daß die Rektifikation bei einem Druck von 6 bis 9 bar durchgeführt wird.Process for the recovery of liquid nitrogen by single-stage rectification of air in a column, the head of which is cooled by a cryogenerator, through it characterized in that the rectification is carried out at a pressure of 6 to 9 bar will. 2, Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß aus der Kolonne Flüss@gkeit mit einem Sauerstoffgehalt von etwa 15 b.s 20 Mol-Prozen; entnommen und zum Tiefidihlen des flüssigen Produktstickstoffes und der aus dem Kolonnensumpf abgezogenen flüssigen Sauerstofffraktion verwendet wird.2, method according to claim 1, characterized in that from the Column liquid with an oxygen content of about 15 to 20 mol percent; taken and for deep-idling the liquid product nitrogen and that from the column bottom withdrawn liquid oxygen fraction is used. 3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß die tiefgekühlte Sauersto£ffraktion entspannt und am Kolonnenkopf verdampft wir.3. The method according to claim 2, characterized in that the frozen Oxygen fraction relaxed and we evaporated at the top of the column. 4. Verfahren nach Anspruch 2, dadurch gel:ennzeichnet, daß die tiefgekühlt Sauerstofffraktion als Produktstrom in einen Speicherbehälter geleitet wird.4. The method according to claim 2, characterized in that the gel: indicates that the frozen Oxygen fraction is passed as a product stream into a storage container.
DE19712133465 1971-07-06 1971-07-06 Liquid nitrogen prodn - by single-column fractional distillation of air at 6 to 9 bar pressure Pending DE2133465A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2390604A1 (en) * 2010-05-27 2011-11-30 Linde AG Method and device for separating a fluid mixture using deep temperature distillation, in particular for acquiring pure krypton

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2390604A1 (en) * 2010-05-27 2011-11-30 Linde AG Method and device for separating a fluid mixture using deep temperature distillation, in particular for acquiring pure krypton

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