EP1309827B1 - Low temperature air fractionation system - Google Patents

Abstract

Low temperature air decomposition plant comprises several modules consisting of a heat exchanger unit, a pressure column (2), and a low pressure column (3); and cold boxes formed as a main box and a secondary box. The secondary box contains at least one of the modules. Preferred Features: At least one or no module is present in the module. A pure argon rectification unit is provided in the plant and comprises partial columns (6, 7), a pure argon line, a pump (11) for recycling reflux liquid from the sump to the second partial column, and an argon head condenser (9). The main box is a pure argon column (8).

Description

The invention relates to a cryogenic air separation plant with several modules, the at least one heat exchanger unit, a pressure column and a Low pressure column include, as well as with the respective modules associated Accessories and with at least two cold boxes in which the modules and / or the Accessories are arranged.

For the recovery of argon by cryogenic rectification of the low pressure column a two-column apparatus at an intermediate point a substantially oxygen, Taken from nitrogen and argon fraction and a crude argon column fed. The argon is then freed of oxygen in the crude argon column and taken at the top of the crude argon column as an oxygen-free product. The Crude argon column is usually arranged so that its bottom is about on Height of Argonabstichs the low pressure column is located.

Under certain circumstances, however, the crude argon column has a very large height, so that the erection and orientation of the crude argon column and the column surrounding thermally insulating sheath, a so-called cold box, very becomes expensive. In EP-A-0 628 777 it is therefore proposed to use the crude argon column split into two partial columns, with the first column of the height of the Argon tap extends up to the top of the low-pressure column and the size the second part column is selected according to the process conditions.

EP-A-0 870-524 uses this approach and proposes a Cryogenic air separation plant before, in which the crude argon column is also divided and the columns are arranged so that the coldbox surrounding the columns completed as completely as possible.

However, larger cryogenic air separation plants of this type are not transportable and must therefore be mounted on site. Also at one Division of the plant into a rectification module, which essentially comprises the Oxygen-nitrogen separation takes place, and in an argon module, the soft Including crude argon column with their accessories, the two cold boxes are often so great that these are no longer transportable. A production in the manufacturing plant is not possible.

The object of the present invention is to provide a cryogenic air separation plant develop that is as easy to manufacture as possible

This object is achieved by a system of the type mentioned solved, in which at least one of the cold boxes as the main box and at least one of Coldboxes is designed as a secondary box, the secondary box at least one of Module includes and the accessories of the arranged in the secondary box Module mainly located in the main box.

In the context of the present description, the components of the Cryogenic air separation plant conceptual in modules, accessories and the Piping divided. The modules include all components that are one of the for the Cryogenic air separation allow specific functions. To the thermally too Insulating modules include in particular machines such as e.g. Expansion machines and cryogenic pumps, heat exchange devices, such as e.g. Main heat exchanger, main condenser, top condensers and Secondary condensers, and apparatus for separating the air, such as countercurrents and Rectification columns.

Accessories include in particular the instrumentation, fittings, Measuring devices, e.g. for flow measurements and analysis, measuring lines as well as Inspection facilities and similar constructive devices. The pipelines are not used in this description unless explicitly stated otherwise counted to the accessories, but considered separately.

Coldbox is understood to mean a container, a casing or a casing, which is suitable, one or more components, in particular modules, one Low-temperature air separation plant record and thermally against the Isolate environment. The coldbox is either thermally insulated itself or can filled with suitable thermal insulation material.

According to the invention, the modules to be accommodated in cold boxes, i. the thermally insulated modules, divided into at least two cold boxes. For example, for the two partial columns of a split crude argon column, respectively a separate coldbox be provided. Pressure column and low pressure column can in be housed another coldbox or also on two cold boxes be split. In this way, the coldbox sizes can be reduced, thereby the transport is facilitated.

The division of the modules on the cold boxes is carried out according to the invention so that at least one coldbox is kept as simple as possible. This is in the sense of Invention achieved in that a coldbox is designed as a secondary box in which essentially only modules without their accessories are located. The secondary box is one Main box assigned to the majority of the accessories in the Nebenbox arranged modules includes. The secondary box can be very simple be executed and is easy and inexpensive to manufacture.

The main box is preferably designed so that it not only the accessories of the associated Nebenbox includes, but even includes one of the modules. It is but in some cases also cheap, in the main box only the accessories of Accommodate modules of the secondary boxes.

The invention is particularly suitable for a cryogenic tuft removal application having a Rohargonrektifikationseinheit, which a first and a second Partial column, a Rohargonleitung, from the upper part of the first column in the lower portion of the second part column leads, means for returning Return liquid from the sump of the second column to the upper part of the first column Partial column and an argon head condenser whose condensation side with the Upper portion of the second part column is connected comprises.

The crude argon column is divided into two at such a plant to the overall height to reduce. The two partial columns are housed in different cold boxes. The first part of the column has no head capacitor itself, but is from the Sump of the second part column supplied with the necessary return liquid. The The first partial column therefore essentially has only connections for the supply and discharge of Liquid and gas to the low pressure column and the second part column on.

Preferably, now also the accessories to the first part column, such. Bequests, measuring and analyzing equipment, not in the first Partial column containing coldbox, but mainly in the coldbox for the second Partial column arranged. The coldbox with the first part column can thus be very simple be carried out and represents in the context of the present invention, the secondary box. The second coldbox contains as a main box, the second part column, the Argon head condenser and the accessories for both partial columns. The Rohargonrektifikationseinheit can thus be divided into two modules, both do not exceed the permissible transport dimensions, with the first module is particularly easy to prefabricate.

In a particularly preferred embodiment is in the main box with the second Partial column also a Reinargonsäule integrated with their accessories. Especially preferably not only are all accessories, but also the entire Piping of the crude argon rectification unit in the main box.

In addition to the described division of Rohargonrektifikationseinheit in one Secondary box with the first part column and a main box with the second part column has In particular, in very large air separation plants, a division of the Rohargonrektifikationseinheit in a main box with two associated secondary boxes as proved favorable.

In this variant, the Rohargonrektifikationseinheit is also in two partial columns divided. Preferably, both partial columns are each arranged in a secondary box. A first side box comprises the first part column, a second side box the second column with the argon head condenser. For the accessories of both Submodules is provided a main box, the most preferred also the Piping of the two partial columns includes.

If the argon rectification unit is provided with a pure argon column, it is cheap to arrange the pure argon column with accessories in the main box.

Preferably more than 60%, more preferably more than 70% and all more preferably more than 80% of the accessories of the modules of the secondary box in the housed in the associated main box. In other words, located in the secondary box not more than 40% of the fittings, not more than 40% of the instrumentation, maximum 40% of test leads and equipment and 40% of the maximum Inspection facilities. Preferably, the proportion in the secondary box is mentioned accessories a maximum of 30%, more preferably a maximum of 20%.

Most preferably, the piping is located in the secondary box housed module mainly in the associated main box, of Advantage more than 60%, of particular advantage more than 70% and of all particular advantage more than 80% of the piping of the main box are assigned.

For production reasons, it is favorable, the main box and the side box cuboid, i.e. with a rectangular plan, because it makes the connections to the Boxes and the passages through the walls of boxes are easier to manufacture. But it also brings benefits if the shape of the main box and / or the secondary box adapted the shape of the male in the box modules and / or accessories is. So it is beneficial to have a rectification column that is housed in a secondary box is to be, for example, the first column of a split Rohargonrektifikationseinheit to surround with a cylindrical box.

The proven in a split crude argon column, inventive concept of Division into a main box with assigned secondary box is of course also on the nitrogen-oxygen rectification unit transferable. It is equally beneficial to the To arrange pressure column and the low pressure column in each case a secondary box and a Hauptbox provide essentially only the accessories of pressure column and Low pressure column includes. Next is a version that is in the main box the low pressure column, optionally with Unterkühlungsgegenströmer, and in the Nebenbox the pressure column, preferably with main capacitor, located, low. The variant in which the coldbox of the pressure column as the main box and the Low pressure column designed as a secondary box, brings benefits. At all mentioned Variants are also preferred a majority of the piping in the main box arranged.

Figur 1

das Verfahrensschema einer erfindungsgemäßen Luftzerlegungsanlage,

Figuren 2a und 2b

erfindungsgemäße Luftzerlegungsanlagen, bei denen eine geteilte Rohargonsäule in einer Haupt- und einer Nebenbox untergebracht ist,

Figuren 3a und 3b

eine alternative Aufteilung einer geteilten Rohargonsäule auf Haupt- und Nebenboxen und die

Figuren 4 bis 6

analoge Ausführungen bei einer Aufteilung von Druck- und Niederdrucksäule auf Haupt- und Nebenboxen.

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

FIG. 1

the process diagram of an air separation plant according to the invention,

FIGS. 2a and 2b

Air separation plants according to the invention, in which a divided crude argon column is accommodated in a main and a secondary box,

FIGS. 3a and 3b

an alternative division of a split crude argon column on main and secondary boxes and the

FIGS. 4 to 6

analogous versions with a distribution of pressure and low pressure column on main and secondary boxes.

The air separation plant shown in FIG. 1 has a double column rectifier Main condenser 1, pressure column 2 and low pressure column 3 for the recovery of Nitrogen at the top of the low pressure column 3 and oxygen from the bottom of the Low pressure column 3 on. The double column is in common with the Unterkühlungsgegenströmer 4 and other cold components, not shown, such as e.g. cryogenic pumps, housed in several cold boxes, their arrangement will be explained in more detail with reference to FIGS 2 to 6.

The argon rectification unit consists of two partial columns 6, 7, which are the crude argon column form a pure argon column 8 and the corresponding top condensers 9, 10th The first part of the column 6 is in the usual way by a line 17 through which a in essential oxygen and argon-containing fraction in the first part of the column. 6 can be fed, connected to the low pressure column 3. The return 18 serves for the return of itself in the bottom of the first part of column 6 accumulating Residual liquid to the low pressure column 3. In this return line 18 is a pump 12 for Promotion of the residual liquid provided.

The first partial column 6 has no top condenser. The return fluid for this Column 6 is formed by the bottom liquid of the second partial column 7, which by means of a pump 11 is pumped to the head of the sub-column 6. In the head capacitor 9 is Return liquid for the second part 7 of the crude argon column by condensation of Overhead fraction in indirect heat exchange against bottom liquid from the pressure column 2, which is supplied via line 19, generated. The resulting steam is via line 13 returned to the low pressure column 3. excess Bottom liquid is from the top condenser 9 via line 14 in the Low pressure column 3 fed. In an analogous manner, the head capacitor 10th the pure argon column 8 supplied with bottoms liquid from the pressure column 2. Waste incurred Steam and excess liquid are supplied via lines 15 and 16 which are in the Lines 13 and 14 open, also passed into the low pressure column 3.

All thermally insulated parts of the system are housed in cold boxes, the filled with perlite. The division of the individual modules and accessories is in the The following explained in more detail with reference to Figures 2 to 6. In the drawings 2 to 6 is in each case, the main box outlined in bold, the auxiliary box dashed lines and the Assignment of main and secondary box indicated by a double arrow. The Rectangle symbolizes the cold box 21 for the main heat exchanger 5. In Simple line width drawn squares and rectangles characterize usual Cold boxes without the Hauptbox- or Nebenboxcharakter invention.

In the arrangement according to FIG. 2a, the main heat exchanger 5, the pressure column 2, the low-pressure column 3 and the two partial columns 6, 7 for Rohargonrektifikation respectively housed in their own coldbox 21, 22, 23, 24, 25. The second part of the column 7th containing coldbox 25 is designed as a main box, which is the first part of the column. 6 containing coldbox 24 is assigned as a secondary box. The main box 25 includes in addition to the partial column 7, the argon head condenser 9, the pure argon column 8 and their head capacitor 10. Femer are more than three quarters of the accessories of the first Partial column 6, i. the measuring and control equipment, the fittings and the Inspection facilities, as well as more than three quarters of the casing of the first Partial column arranged in the main box 25.

FIG. 2b shows an alternative embodiment in which a common cold box 26 is provided for the pressure column 2 and the low pressure column 3. The cold boxes 24, 25 the two sub-columns 6 and 7 also have the explained with reference to Figure 2a Main box-auxiliary box ratio.

The individual cold boxes are interconnected via junction boxes in which For example, the connecting lines extend, connected to each other. It is at all arrangements shown in the figures also advantageous, two or more Coldboxes that need to be connected, right next to each other to connect to each other and to the common wall of coldboxes remove so that a single coldbox is created.

The two embodiments of Figure 3a and Figure 3b differ from those Figures 2a and 2b in that the second part of column 7 also in a Secondary box 27 is located. The main box 28 comprises the majority of the Accessories of the two partial columns 6, 7, the pure argon column 8 and the Capacitors 9, 10 and the pure argon column 8. Further, the cold, i. to be isolated Piping of the two Rohargonteilmodule 6, 7 included in the main box 28. The Pressure column 2 and the low pressure column 3 are each in a separate coldbox 22, 23 housed.

Figure 3b corresponds substantially to Figure 3a, but with the pressure column 2 and the low pressure column 3, analogous to the embodiment of Figure 2b, in a common Coldbox 26 are located. The argon rectification unit with the two partial columns 6, 7 becomes on two secondary boxes 24, 27 for the partial columns 6, 7 and a main box 28, the corresponding accessories and the piping contains, split.

FIGS. 4 to 6 show further embodiments of the invention Concept for the distribution of cold boxes in main and secondary boxes.

In Figure 4a, a cryogenic air separation plant is shown in which the coldbox for the double column consisting of pressure column 2 and low pressure column 3 divided according to the invention. In this case, the low pressure column 3 in a Nebenbox 35 housed. The pressure column 2 with the main capacitor and the Accessories of the low-pressure column 3 is located in the main box 34th Die Rohargonsäule is divided and, as already shown in Figure 2, also in two as Main and secondary box running coldboxes 24, 25 arranged. This execution allows the transport of the individual modules with the associated coldboxes.

Figure 4b shows a modification of the arrangement of Figure 4a, in which the Although the crude argon column divided and housed in two cold boxes 31, 32, in which the two cold boxes 31, 32 for the first and the second partial column 6, 7 in conventional Are executed, i. E. in which all of the respective sub-column 6, 7 associated accessories are also located in the corresponding Coldbox 31, 32.

In a further variant 4c of this embodiment, in particular in a system with a smaller argon rectification unit is a common cold box 33 provided for the two partial columns 6, 7 for argon production. The two Partial columns 6, 7 are usually arranged side by side. It has, however also proved to be favorable, the second partial column 7 with the top condenser under the first partial column 6 provide. Since the sump of the first sub-column 6 at the level of Argon deduction from the low pressure column 3 is located in the cold box 33 below the first sub-column 6 space, which is preferably used for the second sub-column 7. To supply the first part of column 6 with return liquid bottoms liquid is made the second part of the column 7 pumped to the head of the first part of the column 6.

Instead of the design of the pressure column box as the main box and the Low-pressure column box as a secondary box, it can also be cheap, vice versa the Drucksäulenbox 29 as a secondary box and the Niederdrucksäulenbox 30 as the main box perform. Various variants of this embodiment are shown in FIGS. 5a to 5c shown. FIGS. 5a to 5c correspond to the arrangements according to FIGS Figures 4a to 4c, wherein only the main box-Nebenbox-relationship between the Pressure column box and the low pressure column box is reversed. The main capacitor can either with the low pressure column 3 and the accessories of the pressure column. 2 and those of the low-pressure column 3 are arranged in the main box 30 or preferably placed on or above the pressure column 2 and in the secondary box 29th to be built in.

FIGS. 6a to 6d show further advantageous variants. According to FIG 6a is a separate main box 36 for the accessories of the pressure column 2 and the Low pressure column 3 is provided. The pressure column 2 and the low pressure column 3 are In contrast, each housed in a secondary box 29, 35. This has the advantage that the Both secondary boxes 29, 35 are easier to manufacture, since they are essentially only the respective rectification column 2, 3 include. In a preferred embodiment while in the secondary box 29 with the pressure column also still the main capacitor integrated. The two partial columns 6, 7 of the crude argon column are also in two over the main box-secondary box principle according to the invention interconnected.

FIGS. 6b and 6c show slight modifications of the arrangement according to FIG. 6a which the two partial columns 6, 7 on the one hand in two conventional, not housed according to the invention cold boxes 31, 32 (Figure 6b) housed are to be found on the other hand in a common coldbox 33 (Figure 6c). Finally, in Figure 6d, an arrangement is shown in which both the pressure 2 and the low-pressure column 3 and the two sub-columns 6, 7 in separate sub-boxes 29, 35, 24, 27 are housed and two main boxes 36, 28 are provided, the on the one hand the secondary boxes 29, 35, on the other hand associated with the secondary boxes 24, 27 are. Not shown, but depending on the number and size of the accessories too advantageous, is an arrangement in which a single main box with the four secondary boxes 29, 35, 24, 27 is connected.

The different figures are supposed to be the kind of for the different modules used cold boxes, i. whether a main box, a secondary box or a conventional cold box is used, clarify. Their arrangement to each other is not necessarily reproduced correctly in the figures. Preferably, the Coldboxes arranged so that the coldboxes, between which many Pipe connections and other connecting lines run as close as possible stand together. So it is advantageous, for example, the cold box 21 with the Main heat exchanger next to the low pressure column box to arrange and the Pressure column box and the crude argon column box (s) to the low pressure column box to be bordered. The connection of the cold boxes with each other via isolated connection boxes or by joining the affected cold boxes and removing the partition.

Claims (13)

1. Low-temperature air fractionation system having a plurality of modules which comprise at least a heat exchanger unit, a pressure column and a low-pressure column, and having the accessories associated with the respective modules, and having at least two coldboxes, in which the modules and/or the accessories are arranged, characterized in that at least one of the coldboxes is designed as a main box (25, 28, 30, 34, 36) and at least one of the coldboxes is designed as an auxiliary box (24, 27, 29, 35), the auxiliary box (24, 27, 29, 35) containing at least one of the modules (2, 3, 6, 7), and the accessories of the module (2, 3, 6, 7) which is arranged in the auxiliary box (24, 27, 29, 35) being located predominantly in the main box (25, 28, 30, 34, 36).
2. Low-temperature air fractionation system according to Claim 1, characterized in that at least one module (2, 3, 7) is located in the main box (25, 30, 34).
3. Low-temperature air fractionation system according to Claim 1, characterized in that there is no module in the main box (28, 36).
4. Low-temperature air fractionation system according to one of Claims 1 to 3, characterized in that a crude argon rectification unit is provided, which comprises a first and a second part-column (6, 7), a crude argon line, which leads from the upper region of the first part-column (6) into the lower region of the second part-column (7), means (11) for returning reflux liquid from the bottom of the second part-column (7) into the upper region of the first part-column (6) and an argon top condenser (9), the condensation side of which is connected to the upper region of the second part-column (7), the auxiliary box (24) containing the first part-column (6) and the main box (25) containing the second part-column (7) and the argon top condenser (9) as well as the majority of the accessories of the first part-column (6).
5. Low-temperature air fractionation system according to Claim 4, characterized in that the main box (25) contains a pure argon column (8).
6. Low-temperature air fractionation system according to one of Claims 1 to 3, characterized in that a crude argon rectification unit is provided, which comprises a first and a second part-column (6, 7), a crude argon line, which leads from the upper region of the first part-column (6) into the lower region of the second part-column (7), means (11) for returning reflux liquid from the bottom of the second part-column (7) into the upper region of the first part-column (6) and an argon top condenser (9), the condensation side of which is connected to the upper region of the second part-column (7), the main box (28) containing the majority of the accessories of the crude argon rectification unit and the first part-column (6) being accommodated in a first auxiliary box (24) and the second part-column (7) and the argon top condenser (9) being accommodated in a second auxiliary box (27).
7. Low-temperature air fractionation system according to Claim 6, characterized in that the second auxiliary box (27) contains a pure argon column (8).
8. Low-temperature air fractionation system according to one of Claims 1 to 7, characterized in that more than 60%, preferably more than 70%, particularly preferably more than 80%, of the accessories are located in the main box (25, 28, 30, 34, 36).
9. Low-temperature air fractionation system according to one of Claims 1 to 8, characterized in that the pressure column (2) and the low-pressure column (3) are each located in their own auxiliary box (29, 35) and the main box (36) contains substantially only the accessories of the pressure column (2) and the low-pressure column (3).
10. Low-temperature air fractionation system according to one of Claims 1 to 8, characterized in that the low-pressure column (3) is located in the main box (30) and the pressure column (2) is located in the auxiliary box (29).
11. Low-temperature air fractionation system according to one of Claims 1 to 8, characterized in that the pressure column (2) is located in the main box (34) and the low-pressure column (3) is located in the auxiliary box (35).
12. Low-temperature air fractionation system according to one of Claims 1 to 11, characterized in that an auxiliary box which contains a crude argon rectification unit is provided.
13. Low-temperature air fractionation system according to one of Claims 1 to 12, characterized in that the piping assigned to the module (2, 3, 6, 7) which is arranged in the auxiliary box (24, 29, 35) is predominantly located in the main box (25, 28, 30, 34, 36).

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