EP3163237A1 - Distillation column system and method for the production of oxygen by cryogenic decomposition of air - Google Patents

Abstract

The distillation column system and method are for generating oxygen by cryogenic separation of air in a distillation column system comprising a high pressure column (101) and a low pressure column (102), a main condenser (103) configured as a condenser-evaporator, and a Auxiliary column (140). A gaseous oxygen-containing fraction (129a) is introduced into the auxiliary column (140). A nitrogen-containing liquid stream (120, 109b) from the high-pressure column (101), the main condenser (103) or the low-pressure column (102) is fed as reflux to the top of the auxiliary column (140). An argon rich stream (158a) from one intermediate point of the low pressure column (102) is introduced into an argon discharge column (152) having an argon discharge head condenser (155). The argon discharge column (152) and the auxiliary column (140) are arranged in a common container (160), which is designed as a dividing wall column and has a vertical dividing wall (161).

Description

The invention relates to a distillation column system for the production of oxygen by cryogenic separation of air according to the preamble of patent claim 1.

The basics of cryogenic separation of air in general and the construction of two-column plants in particular are in the Monograph "Tiefftemperaturtechnik" by Hausen / Linde (2nd edition, 1985 ) and in an essay by Latimer in Chemical Engineering Progress (Vol. 63, No.2, 1967, page 35 ). The heat exchange relationship between the high-pressure column and the low-pressure column of a double column is usually realized by a main condenser in which head gas of the high-pressure column is liquefied against vaporizing bottom liquid of the low-pressure column.

The distillation column system of the invention can basically be designed as a classic two-column system with high-pressure column and low-pressure column. In addition to the two separation columns for nitrogen-oxygen separation, it can have other devices for obtaining other air components, in particular noble gases, for example krypton-xenon recovery.

The main capacitor is formed in the invention as a condenser-evaporator. The term "condenser-evaporator" refers to a heat exchanger in which a first condensing fluid stream undergoes indirect heat exchange with a second evaporating fluid stream. Each condenser-evaporator has a liquefaction space and an evaporation space, which consist of liquefaction passages or evaporation passages. In the liquefaction space, the condensation (liquefaction) of the first fluid flow is performed, in the evaporation space the evaporation of the second fluid flow. Evaporation and liquefaction space are formed by groups of passages that are in heat exchange relationship with each other.

In this case, the main capacitor as a single or multi-storey bath evaporator, in particular as a cascade evaporator (for example, as in EP 1287302 B1 = US Pat. No. 6,748,763 B2 described), or be designed as a falling film evaporator. It can be formed by a single heat exchanger block or by a plurality of heat exchanger blocks, which are arranged in a common pressure vessel.

A "main heat exchanger" serves to cool feed air in indirect heat exchange with recycle streams from the distillation column system. It may be formed from a single or multiple parallel and / or serially connected heat exchanger sections, for example one or more plate heat exchanger blocks. Separate heat exchangers which specifically serve to vaporize or pseudo-evaporate a single liquid or supercritical fluid without heating and / or vaporization of another fluid, do not belong to the main heat exchanger.

The relative spatial terms "top", "bottom", "above", "below", "above", "below", "next to each other", "vertically", "horizontally" etc. refer here to the spatial orientation of the separation columns in normal operation. An arrangement of two columns or pieces of equipment "one above the other" is understood here to mean that the upper end of the lower of the two apparatus parts is at a lower or the same geodetic height as the lower end of the upper of the two apparatus parts and the projections of the two apparatus parts into one overlap horizontal plane. In particular, the two parts of the apparatus are arranged exactly one above the other, that is, the axes of the two columns extend on the same vertical line.

A plant of the type mentioned and a corresponding method are made DE 1136355 B known.

The invention has for its object to provide such a system very energy efficient and with a particularly high capacity for oxygen production at the same time form so compact that they can be prefabricated as far as possible and then transported to the site. For such transports there are strict limitations regarding the height (transport length) and the diameter (Transport width) of the separation columns. For example, column diameters of a maximum of 4.8 m are often specified.

This object is solved by the features of patent claim 1. In particular, an argon discharge column and an auxiliary column are used and the columns are combined in a particularly advantageous manner.

An "argon discharge column" here refers to a separation column for argon-oxygen separation, which is not used for obtaining a pure argon product but for discharging argon of the air to be separated into the high-pressure column and low-pressure column. Their circuit differs only slightly from that of a conventional crude argon column, but it contains significantly less theoretical plates, namely less than 40, especially between 15 and 30. As in a crude argon column, the bottom portion of an argon discharge column is connected to an intermediate point of the low pressure column and the argon discharge column becomes cooled by a top condenser on the evaporation side relaxed bottom liquid is introduced from the high pressure column; an argon discharge column has no bottom evaporator.

In the auxiliary column, a part of the feed air is treated, in particular at least part of a turbine-relaxed air flow, which is conducted neither into the high-pressure column nor into the low-pressure column.

In the first place, in view of the endeavor to realize a particularly compact system, it seems absurd to use two additional columns in addition to the usual ones, namely the high-pressure column and the low-pressure column. In the context of the invention, however, it has surprisingly been found that overall both a particularly high capacity and a good buildability results. The inventive combination of auxiliary column, Argonausschleussäule and column arrangement leads to a particularly advantageous investment.

In the invention, the auxiliary column is installed so to speak in the Argonausschleussäule, thereby the height of a column can be saved in the invention or conversely, the throughput in the column at existing height can be increased without the column diameter exceeds the permissible transport dimensions. The combination of Argonausschleussäule and auxiliary column is here as referred to as "common container". This has in its interior a vertical partition. This can basically have any shape, such as cylindrical shape; Preferably, however, a flat partition wall is used. The two subspaces, which are formed by the partition, may be the same or different sizes.

Located on one side of the partition are the Argonausschleussäule, in particular their mass transfer elements, on the other the auxiliary column, in particular their mass transfer elements. The mass transfer processes on both sides of the partition are independent of each other.

At the top of the common container, as is usual with argon columns, the argon discharge column overhead condenser can be arranged. Its liquefaction room here communicates fluidically only with the head of the argon discharge column, but not with the head of the auxiliary column.

At the top of the auxiliary column, preferably a first gaseous nitrogen product is obtained, at the top of the low-pressure column a second gaseous nitrogen product. For example, these two nitrogen products may be combined and heated together to about ambient temperature in a supercooling countercurrent and a main heat exchanger.

In many cases, it is better to pass the first and the second top fraction separately - ie in separate passage groups - through the main heat exchanger and thereby heat these fractions against feed air for the high-pressure column. Then, for example, the head of the low-pressure column can be operated under particularly low pressure of, for example, 1.0 to 1.6 bar, wherein at the top of the auxiliary column a pressure of about 0.1 to 0.3 bar higher pressure of 1.1 to 1, 7 bar, which is sufficient to use the top gas of the first gaseous overhead fraction from the auxiliary column as a regeneration gas for a molecular sieve for air purification. The particularly low low-pressure column pressure reduces the energy consumption of the system.

In general, the method according to the invention is particularly well suited for systems of particularly high oxygen capacity of, for example, 80,000 to 170,000 Nm ³ / h. These and other capacity figures in the text refer to a maximum column diameter of 4.8 m.

It is also favorable if the means for introducing a gaseous fraction whose oxygen content is equal to or higher than that of the air are formed in the auxiliary column as means for introducing turbine-relaxed air into the auxiliary column. As a result, the turbine air must only be partially introduced into the low-pressure column.

In principle, the two subspaces of the common container could communicate at their lower end, as is common practice in dividing wall columns. In the invention, however, the two subspaces are preferably completely separated from each other by the common container and the partition are formed so that the partition completely seals the two subspaces of the common container against each other. Thus, the swamps of argon discharge column and auxiliary column are completely independent of each other, both in chemical composition and in the filling level.

Within the scope of the invention, three spatial arrangements of the columns are particularly preferred.

• die Niederdrucksäule neben der Hochdrucksäule und
• der gemeinsame Behälter, insbesondere mit Argonausschleussäulen-Kopfkondensator, über der Hochdrucksäule angeordnet.

Diese Konfiguration ist für Anlagen mit mittlerer Sauerstoffkapazitätgünstig. Der gemeinsame Behälter nutzt die Höhendifferenz zwischen Hochdrucksäule und Niederdrucksäule aus. Unter "mittlerer Sauerstoffkapazität" wird eine Sauerstoffproduktion von beispielsweise 100.000 bis 140.000 Nm³/h bezeichnet.In a first arrangement are

• the low pressure column next to the high pressure column and
• the common container, in particular with Argonausloumnäulen overhead condenser, arranged above the high-pressure column.

This configuration is beneficial for medium oxygen capacity plants. The common container makes use of the height difference between the high-pressure column and the low-pressure column. By "average oxygen capacity" is meant an oxygen production of, for example, 100,000 to 140,000 Nm ³ / h.

• den Hauptkondensator über der Hochdrucksäule,
• die Niederdrucksäule über dem Hauptkondensator und
• den gemeinsamen Behälter, insbesondere mit Argonausschleussäulen-Kopfkondensator, über der Niederdrucksäule anzuordnen.

A second arrangement provides

• the main condenser above the high pressure column,
• the low pressure column above the main condenser and
• to arrange the common container, in particular with argon discharge column overhead condenser, above the low-pressure column.

High-pressure column, main condenser and low pressure column here form a classic double column. Above are argon discharge column and auxiliary column. Such a configuration has a particularly low footprint. This embodiment of the invention has, for example, a capacity of 70,000 to 85,000 Nm ³ / h of oxygen.

• der Hauptkondensator über der Hochdrucksäule,
• die Niederdrucksäule über dem Hauptkondensator und
• der gemeinsame Behälter, insbesondere mit Argonausschleussäulen-Kopfkondensator, neben der Niederdrucksäule angeordnet sind.

Auch hier bilden Hochdrucksäule, Hauptkondensator und Niederdrucksäule eine klassische Doppelsäule. Der gemeinsame Behälter wird ähnlich einer klassischen Argonsäule aufgestellt oder aufgehängt. Sein unteres Ende befindet sich etwa in Höhe des Argonübergangs der Niederdrucksäule. Auf eine Sauerstoff-Transferpumpe zwischen den Säulen kann hier verzichtet werden. Diese Konfiguration ist für Anlagen mit geringer Sauerstoffkapazitätgünstig. Unter "geringer" Sauerstoffkapazität wird eine Sauerstoffproduktion von beispielsweise 80.000 bis 100.000 Nm³/h verstanden.In a third arrangement will be

• the main condenser above the high pressure column,
• the low pressure column above the main condenser and
• the common container, in particular with argon discharge column head condenser, are arranged next to the low-pressure column.

Here too, the high-pressure column, main condenser and low-pressure column form a classic double column. The common container is placed or suspended similar to a classic argon column. Its lower end is located approximately at the level of the argon transition of the low-pressure column. On an oxygen transfer pump between the columns can be omitted here. This configuration is beneficial for low oxygen capacity plants. By "low" oxygen capacity is meant an oxygen production of, for example, 80,000 to 100,000 Nm ³ / h.

Particularly suitable for a large oxygen capacity is a system with two identical distillation column system according to the invention, which are operated in parallel according to claim 6 and supplied from the same source with feed air. Such a plant with twin columns is in itself EP 2865978 A1 described. A "large oxygen capacity" refers to a plant with an oxygen production of more than 140,000 Nm ³ / h, for example up to 170,000 Nm ³ / h and more.

The invention also relates to a method for producing oxygen by cryogenic separation of air according to claims 8 to 14.

Figuren 1a bis 1c

ein erstes Ausführungsbeispiel der Erfindung mit Anordnung von Argonausschleussäule und Hilfssäule über der Hochdrucksäule beziehungsweise über dem Hauptkondensator in drei Varianten,

Figur 2

ein zweites Ausführungsbeispiel mit Zwillingssäulen, bei dem in jedem Teilsystem alle Säulen übereinander angeordnet sind, und

Figur 3

ein drittes Ausführungsbeispiel, bei dem der gemeinsame Behälter neben einer klassischen Doppelsäule angeordnet ist.

The invention and further details of the invention are explained below with reference to embodiments schematically illustrated in the drawings. Hereby show:

FIGS. 1a to 1c

A first embodiment of the invention with arrangement of Argonausschleussäule and auxiliary column above the high-pressure column or over the main capacitor in three variants,

FIG. 2

a second embodiment with twin columns, in which all columns are arranged one above the other in each subsystem, and

FIG. 3

a third embodiment, in which the common container is arranged next to a classic double column.

In FIG. 1a is to see a plant with a single distillation column system. In particular, it has a "mean oxygen capacity" of, for example, 100,000 to 140,000 Nm ³ / h. The distillation column system of the embodiment of the FIG. 1a comprises a high-pressure column 101, a low-pressure column 102, a main condenser 103, an argon discharge column 152 and an auxiliary column 140.

The main capacitor 103 is formed in the example by a six-stage cascade evaporator, so a multi-level pocket evaporator. The pair of columns 101/102 is not arranged in the form of a double column, but next to each other.

The argon discharge column 152 and the auxiliary column are housed according to the invention in a common container 160 with a vertical partition wall 161. The partition wall 161 is flat in the example and extends from the lid to the bottom of the container, so that the two subspaces forming the argon discharge column 152 and the auxiliary column 140 are completely separated; For example, different levels can also form in the sump, as shown in the drawing. An argon discharge head condenser 155 is located immediately above the common container 160; he is here designed as a single-storey bath evaporator.

In the FIG. 1 a shown system comprises an inlet filter 302 for atmospheric air (AIR), a main air compressor 303, an air pre-cooling unit 304, an air cleaning unit 305 (usually formed by a pair of molecular sieve adsorbers), an air compressor 306 (Booster Air Compressor - BAC) with intermediate and aftercoolers and a main heat exchanger 308 on. A total compressed air flow 100 from the cold end of the main heat exchanger 308 is introduced into the high pressure column 101.

The air recompressed in the final compressor 306 to its final pressure is liquefied in the main heat exchanger 308 (or, if its pressure is supercritical, pseudo-liquefied) and fed via lines 311/111 to the distillation column system.

A nitrogen gas stream 104, 114 from the high-pressure column 101 is introduced into the liquefaction space of the main condenser 103. There, liquid nitrogen 115 is generated therefrom, which is passed to the high-pressure column 101 at least to a first part as a first liquid nitrogen stream 105.

A liquid oxygen stream 106 from the bottom of the low-pressure column 102 is conveyed to at least part 106 by means of a pump 106a into the evaporation space of the main condenser 103. Gaseous oxygen 106c formed in the evaporation space of the main condenser 103 is introduced into the first low-pressure column 102 where it forms the rising vapor. If necessary, a second part can be obtained directly as a gaseous oxygen product and heated in the main heat exchanger 308 (not realized in this embodiment). A portion 106d of the liquid oxygen from the pump 106a may be cooled in a subcooling countercurrent 123 and subsequently recovered as a liquid product (LOX).

The reflux liquid 109a for the low pressure column 102 is formed by a nitrogen-enriched liquid 120 which is withdrawn at the high pressure column 101 from an intermediate point (or alternatively directly from the top) and cooled in the subcooling countercurrent 123. From the top of the low-pressure column 102, impure nitrogen 110a is withdrawn and passed as residual gas through the supercooling countercurrent 123 and via the line 32 to the main heat exchanger 308. Another part 109b of the nitrogen-enriched liquid 120 from the high-pressure column 101 is fed to the top of the auxiliary column 140. From the top of the auxiliary column 140 also impure nitrogen 110b is withdrawn and mixed with the impure nitrogen 110a from the low pressure column. The bottom liquid 159 of the auxiliary column 140 is guided to the intermediate point of the low-pressure column 102, at which the bottoms liquid 154a of the high-pressure column 101 is also fed.

From the high-pressure column 101, an oxygen-enriched bottoms liquid stream 151 is withdrawn and cooled in the subcooling countercurrent 123. A first part 154a of the cooled bottom liquid 153 is supplied to the low-pressure column 102. The remainder 154b of the cooled bottom liquid 153 is introduced into the evaporation space of the argon discharge head top condenser 155. The vaporized in the top condenser 155 portion 156 and the remaining liquid portion 157 are the low-pressure column 102 fed. The argon-enriched "product" 163 of the argon column is withdrawn in gaseous form from the argon column 152 or its overhead condenser 155 and passed through the main heat exchanger 308 through a separate passage group via line 164. The bottom liquid 158b of the argon discharge column 152 is led to the intermediate point of the low-pressure column 102, on which the gaseous insert 158a for the argon discharge column 152 is withdrawn.

Alternatively, the argon-enriched fraction 163 could be mixed with the impure nitrogen 110 and the mixture passed through the main heat exchanger.

The liquid air 311 from the main heat exchanger is fed via the line 111 to the high-pressure column 101 at an intermediate point. At least one part 127 is removed again immediately and introduced through the subcooler 123 and via the line 128 into the low-pressure column 102, above the feed of the sump fraction 153. Via line 129 is further gaseous air from a Einblaseturbine 137 in the auxiliary column 140 (line 129a) and / or introduced into the low-pressure column 102 (line 129b). The feed into the low-pressure column takes place at the same point as the feed of the crude oxygen 154a. In a first variant of the embodiment, the entire air 129 is introduced from the injection turbine 137 in the auxiliary column 140. Deviating from this, in a second variant, the air 129 is divided between the two lines 129a and 129b.

As the main product of the distillation column system liquid oxygen 141 is withdrawn from the bottom of the low pressure column 102 and fed via line 14 at least partially to an internal compression. In this case, the liquid oxygen 14 is brought by means of a pump 15 to a high product pressure, evaporated under this high product pressure in the main heat exchanger 308 or (if its pressure is supercritical) pseudo-evaporated, warmed to about ambient temperature and finally stripped off as gaseous pressure oxygen product GOXIC. This represents the main product of the system of the embodiment.

As another product of the system, pressurized nitrogen is withdrawn directly from the top of the high-pressure column 101 (lines 104, 142), passed via line 42 to the main heat exchanger 308, warmed there and finally recovered as gaseous pressure nitrogen product MPGAN. Part of it can be used as sealing gas (seal gas). In addition, a portion 143 of the liquid nitrogen produced in the main condenser 103 may be supplied via line 43 to an internal compression (pump 16) and recovered as gaseous high pressure nitrogen product GANIC. The plant can also supply liquid products LOX, LIN.

The system of FIG. 1a is designed as a two-turbine method with a medium-pressure turbine 138 and an injection turbine 137.

FIG. 1b is different from this FIG. 1a that in FIG. 1b only one injection turbine 137, but no intermediate-pressure turbine is provided.

In addition to the characteristics of FIG. 1 a rejects the system of Figure 1c in the auxiliary column two mass transfer sections 140a and 140b. Between these two sections, a portion 128b of the liquid air 128 is introduced into the auxiliary column. The use of an additional (third) packing section (in Figure 1c not shown) in the auxiliary column below 140b and 129a is possible in principle; then a portion of the gas stream 156 is introduced from the argon overhead condenser at the bottom of the auxiliary column.

In FIG. 2 is a plant with two distillation column systems (twin columns) shown, which is formed according to the invention. It has a "large oxygen capacity" with an oxygen production of, for example, 140,000 to 170,000 Nm ³ / h.

The first distillation column system of the embodiment of the FIG. 2 has a first high-pressure column 101, a first low-pressure column 102, a first main capacitor 103, a first auxiliary column 140 and a first Argonausschleussäule 152 on. A second high-pressure column 201, a second low-pressure column 202, a second main condenser 203, a second auxiliary column 240 and a second argon column 252 belong to the second distillation column system of FIG FIG. 2 illustrated plant. In both distillation column systems, the argon discharge column 152/262 and the auxiliary column 140/240 are each arranged in a common container 160/260 with partition wall 161/261. Both distillation column systems are constructed identically.

Both main capacitors 103, 203 are formed in the example by a three-stage cascade evaporator. The pairs of columns 101/102, 201/202 are arranged in the form of two double columns. The common container 160/260 are each arranged above the double columns, so that one can speak of triple columns. The argon column head condensers 155, 255 sit directly above the common containers 140/240 and are designed as a bath evaporator.

A total compressed air flow 99 from the cold end of the main heat exchanger 308 is branched into a first compressed air partial flow 100 and a second compressed air partial flow 200. The first compressed air sub-stream 100 is introduced into the first high-pressure column 101, the second compressed air sub-stream 200 into the second high-pressure column 201.

The air recompressed in the final compressor 306 to its final pressure is liquefied in the main heat exchanger 308 (or, if its pressure is supercritical, pseudo-liquefied) and fed via line 311 to the distillation column systems where it branches into the streams 111 and 211.

The argon-enriched "product" 163, 263 of the argon column is removed in gaseous form from the argon discharge column 152, 252 or its top condenser 155, 255 and passed via line 164 through a separate passage group through the main heat exchanger 308.

Alternatively, the argon-enriched fractions 163, 263 could be mixed with the impure nitrogen 110a, 110b, 210a, 201b, 32 and the mixture passed through the main heat exchanger.

As the main product of the distillation column systems, liquid oxygen 141, 241 is withdrawn from the evaporation spaces of the main condensers 103, 203, combined and fed via line 14 at least partially to an internal compression. In this case, the liquid oxygen 14 is pumped by a pump 15 to a high product pressure, vaporized under this high product pressure in the main heat exchanger 308 or (if its pressure is supercritical) pseudo-evaporated, warmed to about ambient temperature and finally withdrawn as gaseous pressure oxygen product GOXIC. This represents the main product of the system of the embodiment.

As another product of the plant, pressurized nitrogen is withdrawn directly from the head of the high-pressure columns 101, 201 (lines 142 and 242), together via line 42 to the main heat exchanger 308, where it is warmed up and finally recovered as gaseous compressed nitrogen product MPGAN. Part of it can be used as sealing gas (seal gas). In addition, in each case a part 143, 243 of the liquid nitrogen produced in the main condensers 103, 203 can be supplied via line 43 to an internal compression (pump 16) and can be obtained as gaseous high-pressure nitrogen product GANIC.

The plant can also supply liquid products LOX, LIN. These can be removed separately from each distillation column system as shown.

In a concrete example, the mass transfer elements in the two low-pressure columns 102, 202 are formed exclusively by ordered packing. The oxygen sections of the two low-pressure columns 102, 202 are provided with an ordered packing having a specific surface area of 750 m ² / m ³ or alternatively 1200 m ² / m ³ , in the remaining sections the packing has a specific surface area of 750 or 500 m ² / m ³ on. In addition, the two low pressure columns 102, 202 may have a nitrogen section above the mass transfer areas shown in the drawing; this can then also be equipped with a particularly dense packing (for example with a specific surface area of 1200 m ² / m ³ for the purpose of reducing the height of the column). By way of derogation, it is possible to combine ordered packing of different specific surface area within each of said sections. The argon columns 152, 252 contain in the exemplary embodiment exclusively pack with a specific Surface of 1200 m ² / m ³ or alternatively 750 m ² / m ³ , as well as the auxiliary columns 140 and 240.

In the high-pressure columns 101, 201, the mass transfer elements are preferably formed by ordered packing with a specific surface area of 1200 m ² / m ³ or 750 m ² / m ³ . Alternatively, at least a portion of the mass transfer elements could be formed in one or both high pressure columns 101, 201 by conventional distillation trays, for example through sieve trays.

The system of FIG. 2 is analogous to FIG. 1a is formed as a two-turbine method with a medium-pressure turbine 138 and an injection turbine 137. Alternatively, in the system of FIG. 2 only one injection turbine can be used (see FIG. 1c) ,

Each of the two distillation column systems is independently regulated. The pressure in the low-pressure columns, for example, can be set and controlled separately. Through this decoupling, the overall control effort is made easier and any manufacturing tolerances in both double columns can be better compensated.

The plant of FIG. 3 shows how FIG. 1 a only a single distillation column system on. However, in this case the high-pressure column 101, the main condenser 103 and the low-pressure column 102 are arranged one above the other in the form of a classic double column. The common container 160 with partition 161, auxiliary column 140 and argon discharge column 152 is disposed adjacent to the low-pressure column 102 at a height that allows the bottom liquids 159, 158b of these columns to be introduced into the low-pressure column 102 without pumps. The common container can either be arranged on a scaffold or laterally connected to the low-pressure column 102 or its cold box. An oxygen transfer pump can be omitted since the columns are arranged one above the other.

Claims (14)

Distillation column system for generating oxygen by cryogenic separation of air with - A high pressure column (101) and a low pressure column (102) and - A main capacitor (103), which is designed as a condenser-evaporator, wherein - The liquefaction space of the main condenser (103) with the head of the high pressure column (101) in flow communication (104, 114, 115, 105) and the evaporation space of the main condenser (103) with the low pressure column (102) in flow communication (106, 106b, 106c ), and with an oxygen product line (41, 141, 241) connected to the low pressure column (102, 202), an auxiliary column (140), - Means for introducing a gaseous fraction (129a) whose oxygen content is equal to or higher than that of the air, in the auxiliary column (140) and - A return fluid line (120,109b) for introducing a liquid stream from the high pressure column (101), the main condenser (103) or the low pressure column (102) as reflux to the head of the auxiliary column (140), wherein the liquid stream has a nitrogen content which is at least equal to the one who is airborne, marked by an argon discharge column (152) which is in fluid communication (158a, 158b) with an intermediate point of the low-pressure column (102), an argon discharge column head condenser (155) formed as a condenser-evaporator, the liquefaction space of the argon discharge head condenser (155) being in flow communication with the head of the argon discharge column (152), and - A raw oxygen line (151, 153, 154b) for introducing liquid crude oxygen from the sump of the high-pressure column (101) in the evaporation space of the argon discharge column head capacitor (155), wherein - The argon discharge column (152) and the auxiliary column (140) are arranged in a common container (160) which is formed as a dividing wall column and a vertical partition wall (161), the two subspaces from each other separates, wherein the first subspace the argon discharge column (152) and the second subspace form the auxiliary column (140). A distillation column system according to claim 1, characterized in that the means for introducing a gaseous fraction whose oxygen content is equal to or higher than that of the air are formed in the auxiliary column as means for introducing turbine-relaxed air (129, 129a) into the auxiliary column (140) are. Distillation column system according to one of claims 1 or 6, characterized in that the partition wall (161) completely seals the two subspaces of the common container (160) against each other. Distillation column system according to one of claims 1 to 3, characterized in that - The low pressure column (102) next to the high pressure column (101) and the common container (160) is arranged above the high-pressure column (101), in particular above the main capacitor (103), - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160). Distillation column system according to one of claims 1 to 3, characterized in that the main condenser (103) above the high pressure column (101), - The low-pressure column (102) above the main capacitor (103) and the common container (160) is arranged above the low-pressure column (102), - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160). Cryogenic air separation plant with a first distillation column system according to one of claims 1 to 5, in particular according to claim 5, a second distillation column system according to one of claims 1 to 5, in particular according to claim 5, a main air compressor system (303) for compressing feed air to a feed air pressure, a main heat exchanger system (308) for cooling compressed feed air, - A first air line (100) for introducing feed air into the HDS (101) of the first distillation column system and with a second air line (200) for introducing feed air into the HDS (201) of the second distillation column system. Distillation column system according to one of claims 1 to 3, characterized in that the main condenser (103) above the high pressure column (101), - The low-pressure column (102) above the main capacitor (103) and the common container (160) is arranged next to the low-pressure column (102), - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160). Method of producing oxygen by cryogenic decomposition of air in a distillation column system, the a high pressure column (101) and a low pressure column (102), - A main condenser (103) which is designed as a condenser-evaporator, wherein the liquefaction space of the main condenser (103) with the head of the high-pressure column (102) in flow communication (104, 114, 115, 105) and the evaporation space of the main capacitor (103 ) with the low-pressure column (102) in flow communication (106, 106 b, 106 c), and an auxiliary column (140) having, - An oxygen stream (41, 141, 241) is withdrawn from the low pressure column (102) and recovered as an oxygen product. - A gaseous fraction (129a) whose oxygen content is equal to or higher than that of the air, is introduced into the auxiliary column (140) and a liquid stream (120, 109b) from the high-pressure column (101), the main condenser (103) or the low-pressure column (102) as reflux to the Top of the auxiliary column (140) is applied, wherein the liquid flow has a nitrogen content which is at least equal to that of the air, characterized in that an argon-rich stream (158a) is introduced from an intermediate point of the low-pressure column (102) into an argon discharge column (152), Return line for the argon discharge column (152) is generated in an argon discharge column head condenser (155), which is designed as a condenser-evaporator, wherein the liquefaction space of the argon discharge column top condenser (155) is in flow communication (38) with the head of the argon discharge column (152) stands, - Raw oxygen (151, 153, 154b) from the bottom of the high-pressure column (101) in the evaporation space of the argon discharge column head capacitor (155) is introduced and - The argon discharge column (152) and the auxiliary column (140) are arranged in a common container (160) which is formed as a dividing wall column and a vertical partition wall (161) which separates two subspaces from each other, wherein the first subspace, the Argonausschleussäule (152 ) and the second subspace form the auxiliary column (140). A method according to claim 8, characterized in that the gaseous fraction whose oxygen content is equal to or higher than that of the air, is formed by turbine-relaxed air (129, 129a). Method according to one of claims 8 or 9, characterized in that the dividing wall (161) completely seals the two subspaces of the common container from one another. Method according to one of claims 8 to 10, characterized in that - The low pressure column (102) next to the high pressure column (101) and - The common container (160) are arranged above the high-pressure column, - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160). Method according to one of claims 8 to 10, characterized in that the main condenser (103) above the high pressure column (101), - The low-pressure column (102) above the main capacitor (103) and the common container (160) is arranged above the low-pressure column (102), - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160). Method according to one of claims 8 to 12, which is carried out in a cryogenic air separation plant according to claim 6 and in which - feed air in a main air compressor system (303) is compressed to a feed air pressure " at least a portion of the compressed feed air is cooled to a main heat exchanger system (308), - A first portion of the cooled feed air through a first air line (100) is introduced into the HDS (101) of the first distillation column system and - A second portion of the cooled feed air is introduced through a second air line (200) in the HDS (201) of the second distillation column system. Method according to one of claims 8 to 13, characterized in that the main condenser (103) above the high pressure column (101), - The low-pressure column (102) above the main capacitor (103) and the common container (160) is arranged next to the low-pressure column (102), - In particular, the argon discharge column head capacitor (155) is arranged directly above the common container (160).

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