Nothing Special   »   [go: up one dir, main page]

EP0768503A2 - Triple column air separation process - Google Patents

Triple column air separation process Download PDF

Info

Publication number
EP0768503A2
EP0768503A2 EP96116124A EP96116124A EP0768503A2 EP 0768503 A2 EP0768503 A2 EP 0768503A2 EP 96116124 A EP96116124 A EP 96116124A EP 96116124 A EP96116124 A EP 96116124A EP 0768503 A2 EP0768503 A2 EP 0768503A2
Authority
EP
European Patent Office
Prior art keywords
pressure column
pressure
column
medium
low
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96116124A
Other languages
German (de)
French (fr)
Other versions
EP0768503A3 (en
EP0768503B1 (en
Inventor
Jürgen Dipl.-Phys. Voit
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.)
Linde GmbH
Original Assignee
Linde GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Linde GmbH filed Critical Linde GmbH
Publication of EP0768503A2 publication Critical patent/EP0768503A2/en
Publication of EP0768503A3 publication Critical patent/EP0768503A3/en
Application granted granted Critical
Publication of EP0768503B1 publication Critical patent/EP0768503B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—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
    • F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low 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
    • F25J3/04436—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 at least a triple pressure main column system
    • F25J3/04448—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 at least a triple pressure main column system in a double column flowsheet with an intermediate 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
    • F25J3/04763—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.
    • F25J3/04878—Side by side arrangement of multiple vessels in a main column system, wherein the vessels are normally mounted one upon the other or forming different sections of the same column
    • 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
    • Y10S62/90—Triple column
    • 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
    • Y10S62/939—Partial feed stream expansion, air

Definitions

  • the invention relates to a method for the low-temperature separation of air in a triple column system, which consists of a high-pressure column, a medium-pressure column and a low-pressure column, with the steps (a) to (i) set out in claim 1.
  • a triple column system has at least three columns for nitrogen-oxygen separation.
  • the term includes systems and processes which have further columns for nitrogen-oxygen separation and / or for the production of other air components such as noble gases, for example a crude argon column.
  • a triple column method of the type mentioned above is known from DE-A-2903089. All of the feed air is compressed to a first pressure that is above the medium pressure column pressure, and some of it is fed into the medium pressure column without further pressure-changing measures, another part is further compressed to a second pressure and introduced into the high pressure column. The rest of the compressed feed air is expanded during work and introduced into the low pressure column. However, this process does not work optimally in terms of energy.
  • the invention is therefore based on the object of specifying a method of the type mentioned with particularly high efficiency.
  • This object is achieved in that the first pressure is lower than the operating pressure of the medium pressure column and in that the second part of the feed air is compressed from the first pressure to a third pressure which is at least equal to the operating pressure of the medium pressure column but is lower than the second pressure .
  • the total amount of feed air is therefore only compressed to a relatively low pressure, which is lower than the pressure prevailing in the medium pressure column.
  • the first air part to be introduced into the medium pressure column must be compressed correspondingly higher in a further compressor; that part of the feed air which is fed directly under the low pressure column operating at lower pressure does not need to be brought up to the high pressure of the high pressure column.
  • the cooling requirement of the system is relatively low, for example because a small part of the products is liquid is obtained or it is a pure gas system, there is a particularly low energy consumption.
  • the third part of the feed air is recompressed upstream of the work relaxation to increase the pressure difference during work relaxation.
  • the pressure upon entering work relaxation is preferably between the first pressure and the pressure of the medium pressure column.
  • the energy obtained in the work-relieving relaxation of the third air part or part thereof should be used for the compression of the third air part.
  • the post-compressor is preferably driven exclusively by this internally generated mechanical energy, so that it does not consume any energy introduced from outside.
  • the post-compressor and expansion machine are mechanically coupled, for example, via a common shaft.
  • the high-pressure column can be operated under a relatively low pressure, which is preferably 4.8 bar or less. This results in a particularly low effort when compressing the feed air.
  • the low pressure column is preferably operated under the lowest possible pressure. This is determined by the fact that the top product of the low-pressure column can be removed from the process under essentially atmospheric pressure, if appropriate after passing through one or more heat exchangers; if this overhead product is used as regeneration gas in a cleaning device (e.g. a molecular sieve system), the pressure of the low pressure column must also enable it to operate.
  • a cleaning device e.g. a molecular sieve system
  • part of the first oxygen-enriched bottom fraction is introduced from the high-pressure column into the medium-pressure column. This means that part of the bottom product from the high-pressure column is further broken down, and a larger amount of nitrogen-enriched fraction is obtained at the top of the medium-pressure column, which is available as reflux liquid in the low-pressure column. This further improves rectification in the low pressure column.
  • the bottom fraction from the high-pressure column is preferably introduced into the medium-pressure column at an intermediate point, that is to say at a point which has at least one practical or theoretical floor above the bottom of the medium pressure column and in particular at least one practical or theoretical floor above the point where the second air part is fed into the medium pressure column.
  • the invention also relates to a device for the low-temperature separation of air according to claims 8 to 11.
  • pure nitrogen can also be produced if a conventional pure nitrogen section is additionally arranged at the top of the low-pressure column.
  • Argon extraction is also possible if the low pressure column is followed by argon rectification in a known manner (see for example EP-B-377117).
  • other noble gases can be generated in a known manner.
  • Feed air 1 is compressed in a main air compressor 2 to a first pressure.
  • the compressed feed air 3 is divided into a first partial flow 101, a second partial flow 201 and a third partial flow 301.
  • the first partial flow is brought to a second pressure and the second partial flow is brought to a third pressure lying between the first and the second pressure.
  • the first partial flow and the second partial flow are first compressed together (4) in the compressor 5 to the third pressure and then the first partial flow 101 alone is further compressed in the compressor 102 to the second pressure.
  • the first and the second partial stream can also be compressed independently of one another.
  • the third partial flow which is fed to the expansion machine 305 or the post-compressor 302, can be branched off downstream of one of the compressors 5 or 102.
  • the resulting higher inlet pressure when relaxing allows the cooling capacity to be increased and / or the amount of air blown directly into the low-pressure column to be reduced.
  • the first partial flow 103, which is under the second pressure, and the second partial flow 201, which is under the third pressure, are cooled in a main heat exchanger 6 against product flows and fed into the high-pressure column 7 and into the medium-pressure column 8 (104 and 202, respectively).
  • the high pressure column 7 is operated under a pressure of 4.5 to 5.5 bar, preferably 4.6 to 4.8 bar
  • the medium pressure column 8 is under 2.5 to 3.5 bar, preferably 2.8 to 3.0 bar.
  • the first pressure (in line 3 behind the main air compressor 2) is significantly lower than the high pressure column pressure; the difference is at least 2.5 bar, preferably 3.0 to 3.2 bar.
  • the second pressure is slightly above the high pressure column pressure (for example about 0.1 bar above the pressure at the feed point into the high pressure column) in order to compensate for the pressure drop in the main heat exchanger 6 and in the lines 103 and 104.
  • the third pressure (downstream of the compressor 5) is slightly above the pressure of the medium pressure column in order to ensure the introduction of the second partial flow 201, 202 into the medium pressure column 8.
  • the third partial flow 301 is optionally post-compressed in a post-compressor 302 to a fourth pressure, which can be between the first pressure and the operating pressure of the medium-pressure column and is, for example, 1.5 to 2.5 bar higher than the first pressure.
  • the fourth pressure is correspondingly higher, that is to say, for example, higher than the pressure of the medium pressure column or even higher than the pressure of the high pressure column; in this case it can be up to to 8 bar or more.
  • Via line 303 it goes to the main heat exchanger 6 and from its cold end further (304) to the relaxation machine 305.
  • the work-relieved air 306 is introduced into the low-pressure column 9 at medium height.
  • each compressor 2, 5, 102, 302 The air is cooled behind each compressor 2, 5, 102, 302 in indirect heat exchange with cooling water, as indicated by the aftercoolers shown in the drawing.
  • intermediate cooling is preferably carried out between two stages.
  • a first nitrogen-enriched top fraction is obtained as the top gas and a first oxygen-enriched fraction as the bottom liquid.
  • Top gas 10 is condensed in a first condenser-evaporator 11 and in part 12 in the high pressure column and in another part 13 - if necessary after subcooling in countercurrent 14 - throttled via line 15 into the low-pressure column 9 (16), the operating pressure of which is 1.1 to 1.5 bar, preferably 1.2 to 1.4 bar.
  • a part of the condensed nitrogen-enriched fraction 13 from the high pressure column can be led via the optional line 17 to the top of the medium pressure column 8.
  • the bottom liquid of the high-pressure column is also released via line 18 into the low-pressure column 9 after optional subcooling (14) (19, 20).
  • the feed point is above that of the air 306 which has been relieved of work.
  • a portion 37 (10 to 30%, preferably 15 to 20%) of the high-pressure column bottom liquid 18 is led into the medium-pressure column.
  • the feed point is at least one practical or theoretical floor, preferably two to five theoretical floors above the feed of the second air part 202.
  • a second nitrogen-enriched top fraction and a second oxygen-enriched bottom liquid are obtained in the medium-pressure column 8.
  • the top gas 21 is condensed in a second condenser-evaporator 22 and throttled to a first part 23 in the medium pressure column and to a second part 24 - possibly after subcooling in countercurrent 14 - in the low pressure column 9 (25).
  • the bottom liquid of the medium-pressure column is expanded via line 26, likewise after optional supercooling (14), into the evaporation space of the second condenser-evaporator 22 (27).
  • the vaporized stream 28 is introduced into the low pressure column 9 (29).
  • the feed point for example, at the same level as that of the sump liquid from the high pressure column or slightly above.
  • Steam 31 for the rectification in the low-pressure column 9 is generated by evaporating bottom liquid 30 in the first condenser-evaporator 11.
  • the condenser-evaporator 11 can be arranged differently from the illustration in the bottom of the low-pressure column 9.
  • nitrogen 32 leaves the low-pressure column 9 is warmed to approximately ambient temperature in the heat exchangers 14 and 6, and is withdrawn at 33.
  • Gaseous product oxygen 35 is removed via line 34 and also heated in the main heat exchanger 6. If necessary, the oxygen product or a part thereof can be withdrawn in liquid form (line 36).
  • the liquid oxygen removed can be pressurized and evaporated (internal compression).
  • the cleaning of the feed air is not shown in the drawing. It can be carried out by any of the known methods, for example in a switchable one Heat exchanger (Revex) or in one or more molecular sieve systems. In the latter case, it is possible to subject the entire feed air (line 3) to cleaning together, to treat the three partial streams 103, 201, 303 in separate systems, or also to jointly treat the first and second partial streams by a compressor immediately downstream of the aftercooler of the compressor 5 to send arranged molecular sieve. In the event that, contrary to the illustration in the drawing, the third partial flow behind one of the compressors 5 or 102 is removed and fed to the post-compressor 302, all three partial flows or at least the first and the third partial flow can be cleaned together.
  • Revex Heat exchanger
  • molecular sieve systems molecular sieve
  • the mass transfer elements in the high-pressure column and in the medium-pressure column are formed by still bottoms, those in the low-pressure column by orderly packing.
  • conventional still bottoms, packing (unordered packing) and / or ordered packing can be used in each of the columns in the invention. Combinations of different types of elements in one column are also possible. Because of the low pressure drop, ordered packings in all columns, especially in the low pressure column, are preferred. These further increase the energy-saving effect of the invention.
  • Table 1 for the production of pure oxygen (99.5%) and Table 2 for the production of medium purity oxygen (95.0%).

Landscapes

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

Abstract

Process for the refrigerated separation of air in a 3 column system comprising a high (7), a medium (8) and a low pressure column (9), having the following steps: (a) Compression (2) of inlet air (1) to a first pressure. (b) Feeding of a first portion (101,103,104) of the compressed air (3) to the high pressure column (7), where this air is compressed (5,102) to a second pressure at least equal to the operating pressure of the high pressure column. (c) Feeding of a second portion (201,202) of air to the medium pressure column (8). (d) Work generating expansion (305) of a third portion (301,303,304) of air. (e) Feeding of expanded air (306) to the low pressure column (9). (f) Feeding (19) of at least one portion of a first oxygen enriched sump fraction (18) from the high to the low pressure column. (g) Condensation (11) of a first nitrogen enriched tops fraction (10) from the high pressure column and feeding condensate from this as reflux to the low pressure column. (h) Feeding (28) of at least one portion of a second oxygen enriched sump fraction (26) from the medium to the low pressure column. (i) Condensation (22) of a second nitrogen enriched tops fraction from the medium pressure column and feeding this condensate as reflux to the low pressure column. (j) The first pressure is lower than the operating pressure of the medium pressure column. (k) The second portion of feed air is compressed from a first to a third pressure, which is at least equal to the operating pressure of the medium pressure column, but lower than the second pressure. Also claimed is a device to carry out the above process.

Description

Die Erfindung betrifft ein Verfahren zur Tieftemperaturzerlegung von Luft in einem Dreifachsäulensystem, das aus einer Hochdrucksäule, einer Mitteldrucksäule und einer Niederdrucksäule besteht, mit den im Patentanspruch 1 angeführten Schritten (a) bis (i).The invention relates to a method for the low-temperature separation of air in a triple column system, which consists of a high-pressure column, a medium-pressure column and a low-pressure column, with the steps (a) to (i) set out in claim 1.

Ein Dreifachsäulensystem weist mindestens drei Säulen Zur Stickstoff-Sauerstoff-Trennung auf. Der Begriff schließt Anlagen und Verfahren ein, die weitere Säulen zur Stickstoff-Sauerstoff-Trennung und/oder zur Gewinnung von anderen Luftbestandteilen wie Edelgasen aufweisen, beispielsweise eine Rohargonsäule. Ein Dreifachsäulenverfahren der oben genannten Art ist aus der DE-A-2903089 bekannt. Die gesamte Einsatzluft wird her auf einen ersten Druck verdichtet, der über dem Mitteldrucksäulendruck liegt, und zu einem Teil ohne weitere druckverändernde Maßnahmen in die Mitteldrucksäule eingespeist, zu einem anderen Teil auf einen zweiten Druck weiter verdichtet und in die Hochdrucksäule eingeführt. Der Rest der verdichteten Einsatzluft wird arbeitsleistend entspannt und in die Niederdrucksäule eingeführt. Dieses Verfahren arbeitet jedoch energetisch nicht vollständig optimal.A triple column system has at least three columns for nitrogen-oxygen separation. The term includes systems and processes which have further columns for nitrogen-oxygen separation and / or for the production of other air components such as noble gases, for example a crude argon column. A triple column method of the type mentioned above is known from DE-A-2903089. All of the feed air is compressed to a first pressure that is above the medium pressure column pressure, and some of it is fed into the medium pressure column without further pressure-changing measures, another part is further compressed to a second pressure and introduced into the high pressure column. The rest of the compressed feed air is expanded during work and introduced into the low pressure column. However, this process does not work optimally in terms of energy.

Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art mit besonders hohem Wirkungsgrad anzugeben.The invention is therefore based on the object of specifying a method of the type mentioned with particularly high efficiency.

Diese Aufgabe wird dadurch gelöst, daß der erste Druck niedriger als der Betriebsdruck der Mitteldrucksäule ist und daß der zweite Teil der Einsatzluft von dem ersten Druck auf einen dritten Druck verdichtet wird, der mindestens gleich dem Betriebsdruck der Mitteldrucksäule, aber niedriger als der zweite Druck ist.This object is achieved in that the first pressure is lower than the operating pressure of the medium pressure column and in that the second part of the feed air is compressed from the first pressure to a third pressure which is at least equal to the operating pressure of the medium pressure column but is lower than the second pressure .

Die Gesamtmenge der Einsatzluft wird also nur auf einen relativ niedrigen Druck verdichtet, der geringer als der in der Mitteldrucksäule herrschende Druck ist. Der in die Mitteldrucksäule einzuführende erste Luftteil muß zwar in einem weiteren Verdichter entsprechend höher verdichtet werden; derjenige Teil der Einsatzluft, der ohnehin direkt unter die bei geringerem Druck arbeitende Niederdrucksäule eingespeist wird, braucht jedoch gar nicht erst auf den hohen Druck der Hochdrucksäule gebracht zu werden. Insbesondere dann, wenn der Kältebedarf der Anlage relativ gering ist, weil beispielsweise ein geringer Teil der Produkte flüssig gewonnen wird oder es sich um eine reine Gasanlage handelt, ergibt sich ein besonders niedriger Energieverbrauch.The total amount of feed air is therefore only compressed to a relatively low pressure, which is lower than the pressure prevailing in the medium pressure column. The first air part to be introduced into the medium pressure column must be compressed correspondingly higher in a further compressor; that part of the feed air which is fed directly under the low pressure column operating at lower pressure does not need to be brought up to the high pressure of the high pressure column. Especially when the cooling requirement of the system is relatively low, for example because a small part of the products is liquid is obtained or it is a pure gas system, there is a particularly low energy consumption.

Dabei ist es günstig, wenn der dritte Teil der Einsatzluft stromaufwärts der arbeitsleistenden Entspannung nachverdichtet wird, um die Druckdifferenz bei der arbeitsleistenden Entspannung zu erhöhen. Der Druck beim Eintritt in die arbeitsleistende Entspannung liegt in diesem Fall vorzugsweise zwischen dem ersten Druck und dem Druck der Mitteldrucksäule.It is advantageous if the third part of the feed air is recompressed upstream of the work relaxation to increase the pressure difference during work relaxation. In this case, the pressure upon entering work relaxation is preferably between the first pressure and the pressure of the medium pressure column.

In diesem Fall sollte die bei der arbeitsleistenden Entspannung des dritten Luftteils gewonnene Energie oder ein Teil davon zur Nachverdichtung des dritten Luftteils verwendet werden. Vorzugsweise wird der Nachverdichter ausschließlich durch diese intern erzeugte mechanische Energie angetrieben, so daß er keine von außen eingebrachte Energie verbraucht. Nachverdichter und Entspannungsmaschine sind beispielsweise über eine gemeinsame Welle mechanisch gekoppelt.In this case, the energy obtained in the work-relieving relaxation of the third air part or part thereof should be used for the compression of the third air part. The post-compressor is preferably driven exclusively by this internally generated mechanical energy, so that it does not consume any energy introduced from outside. The post-compressor and expansion machine are mechanically coupled, for example, via a common shaft.

Bei dem erfindungsgemäßen Verfahren kann die Hochdrucksäule unter einem relativ niedrigen Druck betrieben werden, der vorzugsweise bei 4,8 bar oder weniger liegt. Damit ergibt sich ein besonders geringer Aufwand beim Verdichten der Einsatzluft.In the method according to the invention, the high-pressure column can be operated under a relatively low pressure, which is preferably 4.8 bar or less. This results in a particularly low effort when compressing the feed air.

Die Niederdrucksäule wird vorzugsweise unter dem niedrigstmöglichen Druck betrieben. Dieser ist dadurch bestimmt, daß das Kopfprodukt der Niederdrucksäule - gegebenenfalls nach Durchgang durch einen oder mehrere Wärmetauscher - unter im wesentlichen Atmosphärendruck aus dem Verfahren entfernt werden kann; falls dieses Kopfprodukt als Regeneriergas in einer Reinigungseinrichtung (z.B. einer Molekularsiebanlage) eingesetzt wird, muß der Druck der Niederdrucksäule auch deren Betrieb ermöglichen.The low pressure column is preferably operated under the lowest possible pressure. This is determined by the fact that the top product of the low-pressure column can be removed from the process under essentially atmospheric pressure, if appropriate after passing through one or more heat exchangers; if this overhead product is used as regeneration gas in a cleaning device (e.g. a molecular sieve system), the pressure of the low pressure column must also enable it to operate.

Es ist ferner günstig, wenn ein Teil der ersten sauerstoffangereicherten Sumpffraktion aus der Hochdrucksäule in die Mitteldrucksäule eingeleitet wird. Damit wird ein Teil des Sumpfproduktes aus der Hochdrucksäule weiter vorzerlegt, und damit eine größere Menge von stickstoffangereicherter Fraktion am Kopf der Mitteldrucksäule gewonnen, die als Rücklaufflüssigkeit in der Niederdrucksäule zur Verfügung steht. Dies bewirkt eine weitere Verbesserung der Rektifikation in der Niederdrucksäule.It is also advantageous if part of the first oxygen-enriched bottom fraction is introduced from the high-pressure column into the medium-pressure column. This means that part of the bottom product from the high-pressure column is further broken down, and a larger amount of nitrogen-enriched fraction is obtained at the top of the medium-pressure column, which is available as reflux liquid in the low-pressure column. This further improves rectification in the low pressure column.

Die Sumpffraktion aus der Hochdrucksäule wird vorzugsweise an einer Zwischenstelle in die Mitteldrucksäule eingeführt, das heißt an einer Stelle, die mindestens einen praktischen oder theoretischen Boden oberhalb des Sumpfes der Mitteldrucksäule und insbesondere mindestens einen praktischen oder theoretischen Boden oberhalb der Stelle der Einspeisung des zweiten Luftteils in die Mitteldrucksäule liegt.The bottom fraction from the high-pressure column is preferably introduced into the medium-pressure column at an intermediate point, that is to say at a point which has at least one practical or theoretical floor above the bottom of the medium pressure column and in particular at least one practical or theoretical floor above the point where the second air part is fed into the medium pressure column.

Die Erfindung betrifft außerdem eine Vorrichtung zur Tieftemperaturzerlegung von Luft gemäß den Patentansprüchen 8 bis 11.The invention also relates to a device for the low-temperature separation of air according to claims 8 to 11.

Mit dem Verfahren und der Vorrichtung gemäß der Erfindung kann auch reiner Stickstoff produziert werden, wenn am Kopf der Niederdrucksäule zusätzlich ein üblicher Reinstickstoffabschnitt angeordnet wird. Auch die Argongewinnung ist möglich, wenn der Niederdrucksäule auf bekannte Weise (siehe beispielsweise EP-B-377117) eine Argonrektifikation nachgeschaltet ist. Ebenso können weitere Edelgase in bekannter Weise erzeugt werden.With the method and the device according to the invention, pure nitrogen can also be produced if a conventional pure nitrogen section is additionally arranged at the top of the low-pressure column. Argon extraction is also possible if the low pressure column is followed by argon rectification in a known manner (see for example EP-B-377117). Likewise, other noble gases can be generated in a known manner.

Die Erfindung sowie weitere Einzelheiten der Erfindung werden im folgenden anhand eines in der Zeichnung dargestellten bevorzugten Ausführungsbeispiels näher erläutert.The invention and further details of the invention are explained below with reference to a preferred embodiment shown in the drawing.

Einsatzluft 1 wird in einem Hauptluftverdichter 2 auf einen ersten Druck verdichtet. Die verdichtete Einsatzluft 3 wird in einen ersten Teilstrom 101, einen zweiten Teilstrom 201 und einen dritten Teilstrom 301 aufgeteilt. In den Verdichtern 5 und 102 werden der erste Teilstrom auf einen zweiten Druck und der zweite Teilstrom auf einen zwischen dem ersten und dem zweiten Druck liegenden dritten Druck gebracht. Dabei werden der erste Teilstrom und der zweite Teilstrom zunächst gemeinsam (4) im Verdichter 5 auf den dritten Druck und anschließend der erste Teilstrom 101 alleine weiter im Verdichter 102 auf den zweiten Druck komprimiert. Alternativ dazu können der erste und der zweite Teilstrom auch unabhängig voneinander verdichtet werden.Feed air 1 is compressed in a main air compressor 2 to a first pressure. The compressed feed air 3 is divided into a first partial flow 101, a second partial flow 201 and a third partial flow 301. In the compressors 5 and 102, the first partial flow is brought to a second pressure and the second partial flow is brought to a third pressure lying between the first and the second pressure. The first partial flow and the second partial flow are first compressed together (4) in the compressor 5 to the third pressure and then the first partial flow 101 alone is further compressed in the compressor 102 to the second pressure. Alternatively, the first and the second partial stream can also be compressed independently of one another.

Wenn der Kältebedarf der Anlage und/oder die Produktreinheit relativ hoch sind, kann abweichend von der Darstellung in der Zeichnung der dritte Teilstrom, der der Entspannungsmaschine 305 beziehungsweise dem Nachverdichter 302 zugeführt wird, stromabwärts eines der Verdichter 5 oder 102 abgezweigt werden. Durch den damit erreichten höheren Eintrittsdruck beim Entspannen kann die Kälteleistung erhöht und/oder die Menge der direkt in die Niederdrucksäule eingeblasenen Luft verringert werden.If the cooling requirement of the system and / or the product purity are relatively high, in a departure from the illustration in the drawing, the third partial flow, which is fed to the expansion machine 305 or the post-compressor 302, can be branched off downstream of one of the compressors 5 or 102. The resulting higher inlet pressure when relaxing allows the cooling capacity to be increased and / or the amount of air blown directly into the low-pressure column to be reduced.

Der unter dem zweiten Druck stehende erste Teilstrom 103 und der unter dem dritten Druck stehende zweite Teilstrom 201 werden in einem Hauptwärmetauscher 6 gegen Produktströme abgekühlt und in die Hochdrucksäule 7 beziehungsweise in die Mitteldrucksäule 8 eingespeist (104 bzw. 202). Die Hochdrucksäule 7 wird unter einem Druck von 4,5 bis 5,5 bar, vorzugsweise 4,6 bis 4,8 bar betrieben, die Mitteldrucksäule 8 steht unter 2,5 bis 3,5 bar, vorzugsweise 2,8 bis 3,0 bar.The first partial flow 103, which is under the second pressure, and the second partial flow 201, which is under the third pressure, are cooled in a main heat exchanger 6 against product flows and fed into the high-pressure column 7 and into the medium-pressure column 8 (104 and 202, respectively). The high pressure column 7 is operated under a pressure of 4.5 to 5.5 bar, preferably 4.6 to 4.8 bar, the medium pressure column 8 is under 2.5 to 3.5 bar, preferably 2.8 to 3.0 bar.

Der erste Druck (in Leitung 3 hinter dem Hauptluftverdichter 2) ist deutlich niedriger als der Hochdrucksäulendruck; die Differenz beträgt mindestens 2,5 bar, vorzugsweise 3,0 bis 3,2 bar. Der zweite Druck liegt geringfügig über dem Hochdrucksäulendruck (beispielsweise etwa 0,1 bar über dem Druck an der Einspeisestelle in die Hochdrucksäule), um den Druckabfall im Hauptwärmetauscher 6 und in den Leitungen 103 und 104 auszugleichen. Analog dazu liegt der dritte Druck (stromabwärts des Verdichters 5) etwas oberhalb des Drucks der Mitteldrucksäule, um die Einführung des zweiten Teilstroms 201, 202 in die Mitteldrucksäule 8 zu gewährleisten.The first pressure (in line 3 behind the main air compressor 2) is significantly lower than the high pressure column pressure; the difference is at least 2.5 bar, preferably 3.0 to 3.2 bar. The second pressure is slightly above the high pressure column pressure (for example about 0.1 bar above the pressure at the feed point into the high pressure column) in order to compensate for the pressure drop in the main heat exchanger 6 and in the lines 103 and 104. Similarly, the third pressure (downstream of the compressor 5) is slightly above the pressure of the medium pressure column in order to ensure the introduction of the second partial flow 201, 202 into the medium pressure column 8.

Der dritte Teilstrom 301 wird gegebenenfalls in einem Nachverdichter 302 auf einen vierten Druck nachverdichtet, der zwischen dem ersten Druck und dem Betriebsdruck der Mitteldrucksäule liegen kann und beispielsweise 1,5 bis 2,5 bar höher als der erste Druck ist. (Für den Fall, daß der dritte Teilstrom stromabwärts eines der Verdichter 5 oder 102 abgezweigt wird, ist der vierte Druck entsprechend höher, das heißt beispielsweise höher als der Druck der Mitteldrucksäule oder sogar höher als der Druck der Hochdrucksäule; er kann in diesem Fall bis zu 8 bar oder mehr betragen.) Über Leitung 303 geht es zum Hauptwärmetauscher 6 und von dessen kaltem Ende aus weiter (304) zur Entspannungsmaschine 305. Die arbeitsleistend entspannte Luft 306 wird auf mittlerer Höhe in die Niederdrucksäule 9 eingeleitet.The third partial flow 301 is optionally post-compressed in a post-compressor 302 to a fourth pressure, which can be between the first pressure and the operating pressure of the medium-pressure column and is, for example, 1.5 to 2.5 bar higher than the first pressure. (In the event that the third partial flow is branched downstream of one of the compressors 5 or 102, the fourth pressure is correspondingly higher, that is to say, for example, higher than the pressure of the medium pressure column or even higher than the pressure of the high pressure column; in this case it can be up to to 8 bar or more.) Via line 303 it goes to the main heat exchanger 6 and from its cold end further (304) to the relaxation machine 305. The work-relieved air 306 is introduced into the low-pressure column 9 at medium height.

Die Luft wird hinter jedem Verdichter 2, 5,102, 302 in indirektem Wärmeaustausch mit Kühlwasser abgekühlt, wie durch die in der Zeichnung dargestellten Nachkühler angedeutet ist. Bei mehrstufigen Verdichtern wird vorzugsweise zwischen zwei Stufen eine Zwischenkühlung durchgeführt.The air is cooled behind each compressor 2, 5, 102, 302 in indirect heat exchange with cooling water, as indicated by the aftercoolers shown in the drawing. In multi-stage compressors, intermediate cooling is preferably carried out between two stages.

Bei der Rektifikation in der Hochdrucksäule 7 fallen eine erste stickstoffangereicherte Kopffraktion als Kopfgas und eine erste sauerstoffangereicherte Fraktion als Sumpfflüssigkeit an. Kopfgas 10 wird in einem ersten Kondensator-Verdampfer 11 kondensiert und zu einem Teil 12 in die Hochdrucksäule und zu einem anderen Teil 13 - gegebenenfalls nach Unterkühlung im Gegenströmer 14 - über Leitung 15 in die Niederdrucksäule 9 eingedrosselt (16), deren Betriebsdruck 1,1 bis 1,5 bar, vorzugsweise 1,2 bis 1,4 bar, liegt. Ein Teil der kondensierten stickstoffangereicherten Fraktion 13 aus der Hochdrucksäule kann über die optionale Leitung 17 zum Kopf der Mitteldrucksäule 8 geführt werden. Die Sumpfflüssigkeit der Hochdrucksäule wird über Leitung 18 ebenfalls nach optionaler Unterkühlung (14) in die Niederdrucksäule 9 entspannt (19, 20). Die Einspeisestelle liegt oberhalb derjenigen der arbeitsleistend entspannten Luft 306. Vorzugsweise wird ein Teil 37 (10 bis 30 %, vorzugsweise 15 bis 20 %) der Hochdrucksäulen-Sumpfflüssigkeit 18 in die Mitteldrucksäule geführt. Die Einspeisestelle liegt mindestens einen praktischen oder theoretischen Boden, vorzugsweise zwei bis fünf theoretische Böden oberhalb der Einspeisung des zweiten Luftteils 202.During the rectification in the high-pressure column 7, a first nitrogen-enriched top fraction is obtained as the top gas and a first oxygen-enriched fraction as the bottom liquid. Top gas 10 is condensed in a first condenser-evaporator 11 and in part 12 in the high pressure column and in another part 13 - if necessary after subcooling in countercurrent 14 - throttled via line 15 into the low-pressure column 9 (16), the operating pressure of which is 1.1 to 1.5 bar, preferably 1.2 to 1.4 bar. A part of the condensed nitrogen-enriched fraction 13 from the high pressure column can be led via the optional line 17 to the top of the medium pressure column 8. The bottom liquid of the high-pressure column is also released via line 18 into the low-pressure column 9 after optional subcooling (14) (19, 20). The feed point is above that of the air 306 which has been relieved of work. Preferably, a portion 37 (10 to 30%, preferably 15 to 20%) of the high-pressure column bottom liquid 18 is led into the medium-pressure column. The feed point is at least one practical or theoretical floor, preferably two to five theoretical floors above the feed of the second air part 202.

In der Mitteldrucksäule 8 werden eine zweite stickstoffangereicherte Kopffraktion und eine zweite sauerstoffangereicherte Sumpfflüssigkeit gewonnen. Das Kopfgas 21 wird in einem zweiten Kondensator-Verdampfer 22 kondensiert und zu einem ersten Teil 23 in die Mitteldrucksäule und zu einem zweiten Teil 24 - gegebenenfalls nach Unterkühlung im Gegenströmer 14 - in die Niederdrucksäule 9 eingedrosselt (25). Die Sumpfflüssigkeit der Mitteldrucksäule wird über Leitung 26 ebenfalls nach optionaler Unterkühlung (14) in den Verdampfungsraum des zweiten Kondensator-Verdampfers 22 entspannt (27). Der verdampfte Strom 28 wird in die Niederdrucksäule 9 eingeführt (29). Die Einspeisestelle beispielsweise auf derselben Höhe wie diejenige der Sumpfflüssigkeit aus der Hochdrucksäule oder etwas darüber.A second nitrogen-enriched top fraction and a second oxygen-enriched bottom liquid are obtained in the medium-pressure column 8. The top gas 21 is condensed in a second condenser-evaporator 22 and throttled to a first part 23 in the medium pressure column and to a second part 24 - possibly after subcooling in countercurrent 14 - in the low pressure column 9 (25). The bottom liquid of the medium-pressure column is expanded via line 26, likewise after optional supercooling (14), into the evaporation space of the second condenser-evaporator 22 (27). The vaporized stream 28 is introduced into the low pressure column 9 (29). The feed point, for example, at the same level as that of the sump liquid from the high pressure column or slightly above.

Dampf 31 für die Rektifikation in der Niederdrucksäule 9 wird durch Verdampfen von Sumpfflüssigkeit 30 im ersten Kondensator-Verdampfer 11 erzeugt. Der Kondensator-Verdampfer 11 kann abweichend von der Darstellung im Sumpf der Niederdrucksäule 9 angeordnet sein. Als Kopfprodukt verläßt Stickstoff 32 die Niederdrucksäule 9, wird in den Wärmetauschern 14 und 6 auf etwa Umgebungstemperatur angewärmt und bei 33 abgezogen. Gasförmiger Produktsauerstoff 35 wird über Leitung 34 entnommen und ebenfalls im Hauptwärmetauscher 6 erwärmt. Das Sauerstoffprodukt oder ein Teil davon kann bei Bedarf flüssig entnommen werden (Leitung 36). Für die Erzeugung eines Hochdruckprodukts kann der flüssig entnommene Sauerstoff auf Druck gebracht und verdampft werden (Innenverdichtung).Steam 31 for the rectification in the low-pressure column 9 is generated by evaporating bottom liquid 30 in the first condenser-evaporator 11. The condenser-evaporator 11 can be arranged differently from the illustration in the bottom of the low-pressure column 9. As the top product, nitrogen 32 leaves the low-pressure column 9, is warmed to approximately ambient temperature in the heat exchangers 14 and 6, and is withdrawn at 33. Gaseous product oxygen 35 is removed via line 34 and also heated in the main heat exchanger 6. If necessary, the oxygen product or a part thereof can be withdrawn in liquid form (line 36). To produce a high-pressure product, the liquid oxygen removed can be pressurized and evaporated (internal compression).

Die Reinigung der Einsatzluft ist in der Zeichnung nicht dargestellt. Sie kann durch jede der bekannten Methoden erfolgen, beispielsweise in einem umschaltbaren Wärmetauscher (Revex) oder in einer oder mehreren Molekularsiebanlagen. Im letzteren Fall ist es möglich, die gesamte Einsatzluft (Leitung 3) gemeinsam der Reinigung zu unterwerfen, die drei Teilströme 103, 201, 303 in getrennten Anlagen zu behandeln oder auch den ersten und zweiten Teilstrom gemeinsam durch ein unmittelbar stromabwärts des Nachkühlers des Verdichters 5 angeordnetes Molekularsieb zu schicken. Für den Fall, daß abweichend von der Darstellung in der Zeichnung der dritte Teilstrom hinter einem der Verdichter 5 oder 102 abgenommen und dem Nachverdichter 302 zugeleitet wird, können aller drei Teilströme oder zumindest der erste und der dritte Teilstrom gemeinsam gereinigt werden.The cleaning of the feed air is not shown in the drawing. It can be carried out by any of the known methods, for example in a switchable one Heat exchanger (Revex) or in one or more molecular sieve systems. In the latter case, it is possible to subject the entire feed air (line 3) to cleaning together, to treat the three partial streams 103, 201, 303 in separate systems, or also to jointly treat the first and second partial streams by a compressor immediately downstream of the aftercooler of the compressor 5 to send arranged molecular sieve. In the event that, contrary to the illustration in the drawing, the third partial flow behind one of the compressors 5 or 102 is removed and fed to the post-compressor 302, all three partial flows or at least the first and the third partial flow can be cleaned together.

In dem Ausführungsbeispiel werden die Stoffaustauschelemente in der Hochdrucksäule und in der Mitteldrucksäule durch Destillierböden gebildet, diejenigen in der Niederdrucksäule durch geordnete Packung. Grundsätzlich können jedoch bei der Erfindung in jeder der Säulen konventionelle Destillierböden, Füllkörper (ungeordnete Packung) und/oder geordnete Packung eingesetzt werden. Auch Kombinationen verschiedenartiger Elemente in einer Säule sind möglich. Wegen des geringen Druckverlusts werden geordnete Packungen in allen Säulen, insbesondere in der Niederdrucksäule, bevorzugt. Diese verstärken die energiesparende Wirkung der Erfindung weiter.In the exemplary embodiment, the mass transfer elements in the high-pressure column and in the medium-pressure column are formed by still bottoms, those in the low-pressure column by orderly packing. In principle, however, conventional still bottoms, packing (unordered packing) and / or ordered packing can be used in each of the columns in the invention. Combinations of different types of elements in one column are also possible. Because of the low pressure drop, ordered packings in all columns, especially in the low pressure column, are preferred. These further increase the energy-saving effect of the invention.

Die untenstehenden Tabellen zeigen zwei Zahlenbeispiele für den in der Zeichnung dargestellten Prozeß, Tabelle 1 für die Gewinnung von reinem Sauerstoff (99,5 %) und Tabelle 2 für die Gewinnung von Sauerstoff mittlerer Reinheit (95,0 %).

Figure imgb0001
Figure imgb0002
 The tables below show two numerical examples for the process shown in the drawing, Table 1 for the production of pure oxygen (99.5%) and Table 2 for the production of medium purity oxygen (95.0%).
Figure imgb0001
Figure imgb0002

Claims (11)

Verfahren zur Tieftemperaturzerlegung von Luft in einem Dreifachsäulensystem, das aus einer Hochdrucksäule (7), einer Mitteldrucksäule (8) und einer Niederdrucksäule (9) besteht, mit folgenden Schritten: (a) Verdichtung (2) von Einsatzluft (1) auf einen ersten Druck (b) Einleitung eines ersten Teils (101, 103, 104) der verdichteten Einsatzluft (3) in die Hochdrucksäule (7), wobei der erste Teil der Einsatzluft von dem ersten Druck auf einen zweiten Druck verdichtet (5, 102) wird, der mindestens gleich dem Betriebsdruck der Hochdrucksäule (7) ist (c) Einleitung eines zweiten Teils (201, 202) der verdichteten Einsatzluft (3) in die Mitteldrucksäule (8) (d) arbeitsleistende Entspannung (305) eines dritten Teils (301, 303, 304) der verdichteten Einsatzluft (3) (e) Einleitung der arbeitsleistend entspannten Einsatzluft (306) in die Niederdrucksäule (9) (f) Einleitung (19) mindestens eines Teils einer ersten sauerstoffangereicherten Sumpffraktion (18) aus der Hochdrucksäule (7) in die Niederdrucksäule (9) (g) Kondensation (11) einer ersten stickstoffangereicherten Kopffraktion (10) aus der Hochdrucksäule (7) und Einleitung von dabei gewonnenem Kondensat (13, 15) als Rücklauf in die Niederdrucksäule (9) (h) Einleitung (28) mindestens eines Teils einer zweiten sauerstoffangereicherten Sumpffraktion (26) aus der Mitteldrucksäule (8) in die Niederdrucksäule (9) (i) Kondensation (22) einer zweiten stickstoffangereicherten Kopffraktion (21) aus der Mitteldrucksäule (8) und Einleitung (25) von dabei gewonnenem Kondensat (24) als Rücklauf in die Niederdrucksäule (9) dadurch gekennzeichnet, daß (j) der erste Druck niedriger als der Betriebsdruck der Mitteldrucksäule (8) ist und (k) der zweite Teil der Einsatzluft von dem ersten Druck auf einen dritten Druck verdichtet (5) wird, der mindestens gleich dem Betriebsdruck der Mitteldrucksäule (8), aber niedriger als der zweite Druck ist. Method for the low-temperature separation of air in a triple column system consisting of a high pressure column (7), a medium pressure column (8) and a low pressure column (9), with the following steps: (a) Compression (2) of feed air (1) to a first pressure (b) introducing a first part (101, 103, 104) of the compressed feed air (3) into the high-pressure column (7), the first part of the feed air being compressed (5, 102) from the first pressure to a second pressure which is at least equal to the operating pressure of the high pressure column (7) (c) introducing a second part (201, 202) of the compressed feed air (3) into the medium pressure column (8) (d) work-relieving relaxation (305) of a third part (301, 303, 304) of the compressed feed air (3) (e) introduction of the work-relaxed air (306) into the low pressure column (9) (f) introducing (19) at least part of a first oxygen-enriched bottom fraction (18) from the high-pressure column (7) into the low-pressure column (9) (g) condensation (11) of a first nitrogen-enriched top fraction (10) from the high-pressure column (7) and introduction of the condensate (13, 15) thus obtained as return into the low-pressure column (9) (h) introducing (28) at least part of a second oxygen-enriched bottom fraction (26) from the medium-pressure column (8) into the low-pressure column (9) (i) condensation (22) of a second nitrogen-enriched top fraction (21) from the medium pressure column (8) and introduction (25) of the condensate (24) obtained thereby as return into the low pressure column (9) characterized in that (j) the first pressure is lower than the operating pressure of the medium pressure column (8) and (k) the second part of the feed air is compressed (5) from the first pressure to a third pressure which is at least equal to the operating pressure of the medium pressure column (8) but lower than the second pressure. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der dritte Teil (301) der Einsatzluft stromaufwärts der arbeitsleistenden Entspannung (305) nachverdichtet (302) wird.A method according to claim 1, characterized in that the third part (301) of the feed air is post-compressed (302) upstream of the work relaxation (305). Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß bei der arbeitsleistenden Entspannung (305) des dritten Luftteils (304) gewonnene Energie zur Nachverdichtung (302) des dritten Luftteils (301) verwendet wird.Method according to Claim 2, characterized in that the energy obtained in the work-relieving relaxation (305) of the third air part (304) is used for post-compression (302) of the third air part (301). Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Betriebsdruck am Kopf der Hochdrucksäule etwa 4,8 bar oder weniger beträgt.Method according to one of claims 1 to 3, characterized in that the operating pressure at the top of the high pressure column is approximately 4.8 bar or less. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Niederdrucksäule (9) unter einem nur knapp überatmosphärischen Druck betrieben wird, der ausreicht, um die Kopffraktion (32, 33) der Niederdrucksäule (9) - gegebenenfalls nach Durchgang durch einen oder mehrere Wärmetauscher (14, 6) - unter im wesentlichen Atmosphärendruck aus dem Verfahren zu entfernen und/oder als Regeneriergas in einer Reinigungseinrichtung einzusetzen.Method according to one of claims 1 to 4, characterized in that the low-pressure column (9) is operated under a slightly superatmospheric pressure which is sufficient to remove the top fraction (32, 33) of the low-pressure column (9) - if appropriate after passage through one or several heat exchangers (14, 6) - to be removed from the process at substantially atmospheric pressure and / or to be used as regeneration gas in a cleaning device. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß ein Teil (37) der ersten sauerstoffangereicherten Sumpffraktion (18) aus der Hochdrucksäule (7) in die Mitteldrucksäule (8) eingeleitet wird.Method according to one of claims 1 to 5, characterized in that a part (37) of the first oxygen-enriched bottom fraction (18) from the high pressure column (7) is introduced into the medium pressure column (8). Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß der Teil (37) der ersten sauerstoffangereicherten Sumpffraktion aus der Hochdrucksäule an einer Zwischenstelle in die Mitteldrucksäule (8) eingeführt wird.Method according to claim 6, characterized in that the part (37) of the first oxygen-enriched bottom fraction from the high pressure column is introduced at an intermediate point into the medium pressure column (8). Vorrichtung zur Tieftemperaturzerlegung von Luft in einem Dreifachsäulensystem, das eine Hochdrucksäule (7), eine Mitteldrucksäule (8) und eine Niederdrucksäule (9) aufweist, mit (a) einem Hauptluftverdichter (2) zur Verdichtung von Einsatzluft (1) auf einen ersten Druck, (b) mit einer ersten Teilstromleitung (101, 103, 104), die mit dem Austritt des Hauptluftverdichters (2) und mit der Hochdrucksäule (7) verbunden ist, wobei die erste Teilstromleitung durch Mittel (5, 102) zur Verdichtung von Einsatzluft von dem ersten Druck auf einen zweiten Druck, der mindestens gleich dem Betriebsdruck der Hochdrucksäule (7) ist, führt (c) mit einer zweiten Teilstromleitung (201, 202), die mit dem Austritt des Hauptluftverdichters (2) und mit der Mitteldrucksäule (8) verbunden ist, (d) mit einer dritten Teilstromleitung (301, 303, 304, 306), die mit dem Austritt des Hauptluftverdichters (2) verbunden ist und durch eine Entspannungsmaschine (305) zur Niederdrucksäule (9) führt, (e) mit Mitteln zur Einleitung (13, 15, 16; 24, 25) von Flüssigkeit vom Kopf der Hochdrucksäule (7) und vom Kopf der Mitteldrucksäule (8) in die Niederdrucksäule (9) sowie zur Einleitung (18, 19, 20; 26, 27, 28 29) von Sumpfflüssigkeit aus der Hochdrucksäule (7) und aus der Mitteldrucksäule (8) in die Niederdrucksäule (9), gekennzeichnet durch (f) Mittel (5) zur Verdichtung von Einsatzluft (4) von dem ersten Druck auf einen dritten Druck, der mindestens gleich dem Betriebsdruck der Mitteldrucksäule (8) ist, deren Eintritt mit dem Austritt des Hauptluftverdichters (2) und deren Austritt mit der zweiten Teilstromleitung (201, 202) verbunden ist. Device for the low-temperature separation of air in a triple column system, which has a high pressure column (7), a medium pressure column (8) and a low pressure column (9) (a) a main air compressor (2) for compressing feed air (1) to a first pressure, (b) with a first partial flow line (101, 103, 104) which is connected to the outlet of the main air compressor (2) and to the high pressure column (7), the first partial flow line being provided by means (5, 102) for compressing feed air from the first pressure to a second pressure which is at least equal to the operating pressure of the high pressure column (7) (c) with a second partial flow line (201, 202) which is connected to the outlet of the main air compressor (2) and to the medium pressure column (8), (d) with a third partial flow line (301, 303, 304, 306), which is connected to the outlet of the main air compressor (2) and leads to a low-pressure column (9) through an expansion machine (305), (e) with means for introducing (13, 15, 16; 24, 25) liquid from the top of the high-pressure column (7) and from the top of the medium-pressure column (8) into the low-pressure column (9) and for introducing (18, 19, 20 ; 26, 27, 28 29) of sump liquid from the high pressure column (7) and from the medium pressure column (8) into the low pressure column (9), marked by (f) means (5) for compressing feed air (4) from the first pressure to a third pressure which is at least equal to the operating pressure of the medium-pressure column (8), the entry of which occurs with the outlet of the main air compressor (2) and the exit of which with the second partial flow line (201, 202) is connected. Vorrichtung nach Anspruch 10, gekennzeichnet durch einen Nachverdichter (302), der in der dritten Teilstromleitung (301, 303) stromaufwärts der Entspannungsmaschine (305) angeordnet ist.Apparatus according to claim 10, characterized by a post-compressor (302) which is arranged in the third partial flow line (301, 303) upstream of the expansion machine (305). Vorrichtung nach Anspruch 9, gekennzeichnet durch Mittel zur Übertragung von mechanischer Energie von der Entspannungsmaschine (305) auf den Nachverdichter (302).Apparatus according to claim 9, characterized by means for the transmission of mechanical energy from the expansion machine (305) to the post-compressor (302). Vorrichtung nach einem der Ansprüche 8 bis 10, gekennzeichnet durch Mittel (37) zur Einleitung von Sumpfflüssigkeit aus der Hochdrucksäule (7) in die Mitteldrucksäule (8).Device according to one of claims 8 to 10, characterized by means (37) for introducing sump liquid from the high pressure column (7) into the medium pressure column (8).
EP96116124A 1995-10-11 1996-10-09 Triple column air separation process Expired - Lifetime EP0768503B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19537913 1995-10-11
DE19537913A DE19537913A1 (en) 1995-10-11 1995-10-11 Triple column process for the low temperature separation of air

Publications (3)

Publication Number Publication Date
EP0768503A2 true EP0768503A2 (en) 1997-04-16
EP0768503A3 EP0768503A3 (en) 1998-02-04
EP0768503B1 EP0768503B1 (en) 2001-07-25

Family

ID=7774605

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96116124A Expired - Lifetime EP0768503B1 (en) 1995-10-11 1996-10-09 Triple column air separation process

Country Status (3)

Country Link
US (1) US5730004A (en)
EP (1) EP0768503B1 (en)
DE (2) DE19537913A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0838647A2 (en) * 1996-10-25 1998-04-29 Air Products And Chemicals, Inc. A three column cryogenic cycle for the production of impure oxygen and pure nitrogen
FR2774753A1 (en) * 1998-02-06 1999-08-13 Air Liquide AIR DISTILLATION SYSTEM COMPRISING MULTIPLE CRYOGENIC DISTILLATION UNITS OF THE SAME TYPE
GB2334085B (en) * 1998-02-06 2001-12-12 Air Liquide Air distillation plant
DE19933558B4 (en) * 1999-07-16 2007-09-13 Linde Ag Three-column process and apparatus for the cryogenic separation of air

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6205815B1 (en) 1997-04-11 2001-03-27 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Plant for separation of a gas mixture by distillation
DE10103968A1 (en) * 2001-01-30 2002-08-01 Linde Ag Three-pillar system for the low-temperature separation of air
DE10113791A1 (en) * 2001-03-21 2002-10-17 Linde Ag Recovery of argon comprises using air decomposition system consisting of high pressure column, low pressure column and middle pressure column
US6397631B1 (en) * 2001-06-12 2002-06-04 Air Products And Chemicals, Inc. Air separation process
JP5425100B2 (en) * 2008-01-28 2014-02-26 リンデ アクチエンゲゼルシャフト Cryogenic air separation method and apparatus
DE102009023900A1 (en) 2009-06-04 2010-12-09 Linde Aktiengesellschaft Method for cryogenic separation of air with distillation column system for nitrogen-oxygen separation, involves producing oxygen-enriched fraction and nitrogen fraction in high pressure column, and supplying nitrogen to low pressure column
FR2946735B1 (en) * 2009-06-12 2012-07-13 Air Liquide APPARATUS AND METHOD FOR AIR SEPARATION BY CRYOGENIC DISTILLATION.
FR2953915B1 (en) * 2009-12-11 2011-12-02 Air Liquide METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION
US8978413B2 (en) * 2010-06-09 2015-03-17 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Rare gases recovery process for triple column oxygen plant

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2903089A1 (en) * 1979-01-26 1980-07-31 Linde Ag METHOD FOR OBTAINING OXYGEN FROM AIR
EP0377117B1 (en) * 1988-12-01 1992-03-25 Linde Aktiengesellschaft Air separation process and apparatus
GB2284880A (en) * 1993-12-15 1995-06-21 Boc Group Plc Air separation using triple column rectification
EP0694745A1 (en) * 1994-07-25 1996-01-31 The BOC Group plc Air separation

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2854508C2 (en) * 1978-12-16 1981-12-03 Linde Ag, 6200 Wiesbaden Method and device for the low-temperature decomposition of a gas mixture
DE3817244A1 (en) * 1988-05-20 1989-11-23 Linde Ag METHOD FOR DEEP TEMPERATURE DISPOSAL OF AIR
US5069699A (en) * 1990-09-20 1991-12-03 Air Products And Chemicals, Inc. Triple distillation column nitrogen generator with plural reboiler/condensers
US5233838A (en) * 1992-06-01 1993-08-10 Praxair Technology, Inc. Auxiliary column cryogenic rectification system
GB9213776D0 (en) * 1992-06-29 1992-08-12 Boc Group Plc Air separation
US5471843A (en) * 1993-06-18 1995-12-05 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process and installation for the production of oxygen and/or nitrogen under pressure at variable flow rate
US5341646A (en) * 1993-07-15 1994-08-30 Air Products And Chemicals, Inc. Triple column distillation system for oxygen and pressurized nitrogen production
US5386692A (en) * 1994-02-08 1995-02-07 Praxair Technology, Inc. Cryogenic rectification system with hybrid product boiler
GB9414938D0 (en) * 1994-07-25 1994-09-14 Boc Group Plc Air separation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2903089A1 (en) * 1979-01-26 1980-07-31 Linde Ag METHOD FOR OBTAINING OXYGEN FROM AIR
EP0377117B1 (en) * 1988-12-01 1992-03-25 Linde Aktiengesellschaft Air separation process and apparatus
GB2284880A (en) * 1993-12-15 1995-06-21 Boc Group Plc Air separation using triple column rectification
EP0694745A1 (en) * 1994-07-25 1996-01-31 The BOC Group plc Air separation

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0838647A2 (en) * 1996-10-25 1998-04-29 Air Products And Chemicals, Inc. A three column cryogenic cycle for the production of impure oxygen and pure nitrogen
EP0838647A3 (en) * 1996-10-25 1998-10-21 Air Products And Chemicals, Inc. A three column cryogenic cycle for the production of impure oxygen and pure nitrogen
FR2774753A1 (en) * 1998-02-06 1999-08-13 Air Liquide AIR DISTILLATION SYSTEM COMPRISING MULTIPLE CRYOGENIC DISTILLATION UNITS OF THE SAME TYPE
GB2334085B (en) * 1998-02-06 2001-12-12 Air Liquide Air distillation plant
DE19904527B4 (en) * 1998-02-06 2007-07-05 L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude Air distillation unit with several cryogenic distillation units of the same type
DE19904526B4 (en) * 1998-02-06 2008-06-26 L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude Air distillation plant and associated cold box
DE19964549B4 (en) * 1998-02-06 2010-07-15 L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude Air distillation plant and associated cold box
DE19933558B4 (en) * 1999-07-16 2007-09-13 Linde Ag Three-column process and apparatus for the cryogenic separation of air
DE19933558C5 (en) * 1999-07-16 2010-04-15 Linde Ag Three-column process and apparatus for the cryogenic separation of air

Also Published As

Publication number Publication date
DE59607348D1 (en) 2001-08-30
DE19537913A1 (en) 1997-04-17
EP0768503A3 (en) 1998-02-04
EP0768503B1 (en) 2001-07-25
US5730004A (en) 1998-03-24

Similar Documents

Publication Publication Date Title
EP1139046B1 (en) Process and device for producing high pressure oxygen product by cryogenic air separation
EP1243882B1 (en) Production of argon using a triple pressure air separation system with an argon column
EP1067345B1 (en) Process and device for cryogenic air separation
DE69105601T3 (en) Air separation.
EP1031804B1 (en) Air separation process with nitrogen recycling
EP1074805B1 (en) Process for producing oxygen under pressure and device therefor
DE19908451A1 (en) A low temperature air fractionating system uses a rectification unit comprising pressure and low pressure columns and a nitrogen fraction recycle to the system air feed inlet, to provide bulk nitrogen
EP1376037A1 (en) Air separation process and apparatus with a mixing column and krypton and xenon recovery
EP2236964A1 (en) Method and device for low-temperature air separation
WO2016131545A1 (en) Method and apparatus for obtaining a compressed nitrogen product
EP0768503B1 (en) Triple column air separation process
EP1146301A1 (en) Process and apparatus for the production of high pressure nitrogen from air separation
EP3290843A2 (en) Method and device for extracting pressurised nitrogen and pressurised nitrogen by cryogenic decomposition of air
EP0948730A1 (en) Method and device for producing compressed nitrogen
DE19609490A1 (en) Oxygen-production process with reduced energy requirement
DE19951521A1 (en) Recovering pressurized product by low temperature decomposition of air in rectification system comprises cold compressing heat carrier stream before introducing into mixing column
EP2053331A1 (en) Method and device for low-temperature air separation
DE69512821T2 (en) Method and device for producing oxygen by rectification of air
DE19933558C5 (en) Three-column process and apparatus for the cryogenic separation of air
DE10052180A1 (en) Three-column system for the low-temperature separation of air
DE19725821A1 (en) Air separation process
DE102010056569A1 (en) Method for recovery of pressurized nitrogen product in distilling column system, involves making secondary portion of vaporized/pseudo-vaporized nitrogen flow in indirect heat exchange with oxygen-enriched liquid of high pressure column
DE19543395A1 (en) Double column process and device for the low temperature separation of air
DE19623322A1 (en) Double column air sepn. plant
DE2307004A1 (en) Liquefied nitrogen - with liquefied natural gas as refrigerant

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE ES FR GB IT

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE ES FR GB IT

17P Request for examination filed

Effective date: 19980706

17Q First examination report despatched

Effective date: 20000426

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR GB IT

REF Corresponds to:

Ref document number: 59607348

Country of ref document: DE

Date of ref document: 20010830

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20011012

ET Fr: translation filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20020131

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20021008

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20021009

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20021011

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20031009

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040501

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20031009

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040630

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20051009