WO2018010851A1 - Method for cold-drawing a container jacket of a heat exchanger - Google Patents

Abstract

The invention relates to a method for cold-drawing a container jacket (11) of a container (10) for a heat exchanger (1) for the indirect transfer of heat between a first medium (M1) and a second medium (M2), wherein the container jacket (11) at least partially encloses a jacket space (12) for receiving the first medium (M1), and wherein an internal pressure (p_i) is provided in the jacket space (12), which is increased in comparison to the ambient pressure (p_u), so that the container jacket (11) is cold-drawn by the internal pressure (p_i). According to the invention, measures are taken, which serve to ensure that at least one additional component is not deformed during cold-drawing.

Description

 description

Method for cold stretching a container shell of a heat exchanger

The invention relates to a method for cold stretching a container shell of a container of a heat exchanger.

Various types of heat exchangers, such as e.g. wound heat exchangers, straight tube heat exchangers and core-in-shell heat exchangers, have pressure-stable containers for holding liquid and / or gaseous media. The

Wall thickness of these containers is designed according to the state of the art according to the required operating pressure, for example in the case of cylindrical containers according to the boiler formula (DIN2413). Due to the high operating pressures required such containers often have large wall thicknesses, which leads to a high weight and high production costs. In the construction of storage containers for cryogenic media, the so-called cold stretching is used according to the prior art (EN13458 Anh. J, DE 36 03 415 A1). In this method, the container is exposed by applying an internal pressure of a tensile stress between yield strength and fracture limit of the material. As a result, the container deforms plastically, with the wall thickness of the container is reduced to the same extent as the strength of the wall material increases. By means of cold stretching, it is possible to produce a container of smaller wall thickness with the same internal volume and the same pressure stability compared to conventionally produced containers. However, deformations of the container are produced by cold stretching, whereby attachment parts are no longer stable in shape and position. This leads in particular to tube sheets to leaks and can thus lead to a functional loss. As a result, the object is to provide a method of the type mentioned, which at least partially mitigates the disadvantages mentioned above. This object by the inventive method for cold stretching a

Container jacket of a container of a heat exchanger to the indirect

Heat transfer between a first medium and a second medium according to claim 1 solved. Preferred embodiments of the invention

Methods are given in subclaims 2 to 12 and are described below.

In the method according to the invention, a container jacket of a container of a heat exchanger for indirect heat transfer between a first medium and a second medium is provided, the container jacket at least partially enclosing a jacket space for receiving the first medium. In the shell space, an increased internal pressure is provided compared to the ambient pressure, so that the tank shell is cold-stretched by the internal pressure, i. deformed at least in sections, is.

In this case, according to the invention, a component mechanically connected to the container jacket is provided, wherein a counterforce acting counter to the internal pressure is exerted on this at least one component, so that the at least one component is stressed by the internal pressure prevailing in the jacket space during cold stretching of the component

Container shell is not deformed.

Alternatively, it is also conceivable that at least one mechanically connected to the container shell component is provided, which with the internal pressure

is acted upon and due to its pressure stability during cold stretching of

Container shell is not deformed.

The provided internal pressure is also referred to as stretching pressure. The internal pressure is adjusted in such a way that a tensile stress acts on the corresponding material of the container, which lies between the yield strength and the fracture limit of the material. In particular, for example, an internal pressure between 1, 5 and 1, 7 times the operating pressure of the container is set. By means of the internal pressure, in particular the wall thickness of the container casing is at least reduced locally by plastic deformation during the cold-stretching process. To provide the internal pressure, for example, a fluid, that is, a liquid or a gas, is introduced into the container at elevated pressure. The cold stretching can in particular in an early manufacturing step of

Heat exchanger can be performed with the container without additional components, with additional components can be grown after cold stretching to the container. Alternatively, the container can be exposed to further components, in particular the finished heat exchanger or a manufacturing intermediate stage, the Kaltreckvorgang.

By cold stretching of the container advantageously the wall thickness of the container can be reduced with constant pressure stability. This reduces the necessary weight of the container in relation to the internal volume. Thus, material costs are saved. In addition, the transport weight of the container is reduced. Due to the lower weight also reduces the cost of subsequent manufacturing steps, especially the production time and lead time, and the required crane loads during assembly. As a result, the manufacturing costs can be lowered.

The cold stretching causes a deformation of the container, which in particular can lead to a shape and position instability of attachments. The use of pressure-stable components or the counterforce provided advantageously prevents such deformation of attachments.

According to a further embodiment of the method, the counterforce is provided by a stabilizing means for a mechanically connected to the container shell component, wherein the stabilizing agent is non-positively, material and / or positively connected to the component.

According to a further embodiment of the method, the counterforce is provided by means of a support structure, wherein the support structure is arranged around the entire container shell. Such a support structure may be, for example, a steel construction, in which the entire container, or the entire heat exchanger, is installed. In particular, attachments (e.g.

Supports) attached to the steel structure. According to a further embodiment of the method, the component is arranged in the jacket space or adjoins it.

 According to a further embodiment of the method, the component is a tube, wherein the counterforce is generated by a counter-pressure provided in the tube, which counteracts the internal pressure. The tube can be a tube for receiving a second medium, wherein during operation of the heat exchanger between the first medium located in the jacket space and that in the tube

located second medium heat is exchanged. In particular, the heat exchanger has a plurality of tubes, wherein the counterforce is generated by a counter-pressure provided in a plurality of tubes.

According to a further embodiment of the method, the component is a

Container shell unilaterally final tube sheet, the at least one opening, in particular a through hole, for connecting a in the shell space

Having running pipe, the counterforce is provided by a back pressure acting on a side facing away from the jacket space of the tube sheet on the tube sheet. Such tube sheets are especially at

Straight tube heat exchangers and wound heat exchangers used.

In particular, the tube plate adjoins a collector, which forms a space for receiving the second medium. By means of the collector, the second medium can be distributed over several tubes through the openings of the tube bottom. In particular, the counter-pressure can be made available in the collector in fluid communication with the openings of the tube bottom.

According to a further embodiment of the method, the tube is designed to receive the second medium so that the two media can exchange heat indirectly.

In this case, the at least one tube is arranged in the jacket space such that, during operation of the heat exchanger, indirect heat is transferred between the first medium located in the jacket space and the second medium flowing through the tube.

According to a further embodiment of the method, the heat exchanger has a plurality of tubes for passing the second medium through the

Shell space, wherein the plurality of tubes substantially parallel along a longitudinal axis of the container casing extends. Such heat exchangers are also referred to as Geradrohrwärmeübertrager.

According to a further embodiment of the method, the tube is helically wound on a core tube arranged in the jacket space. The core tube takes on the load of at least one tube. In particular, the core tube is along a

Longitudinal axis of the shell space extends. Such heat exchangers are also referred to as wound heat exchangers. In a wound heat exchanger, in particular a plurality of tubes are wound on the core tube, so that a tube bundle is formed with a plurality of tube layers whose weight receives the core tube.

According to a further embodiment of the method, the heat exchanger has at least one tube bundle arranged in the jacket space, the at least one tube bundle each having a plurality of tubes for passing the second medium through the jacket space.

According to a further embodiment of the method, the tube is an im

Shell space arranged core tube of a wound heat exchanger. According to another embodiment, the counterforce is provided by providing a back pressure in the core tube.

According to a further embodiment of the method, the at least one component is arranged by a in the shell space of the container shell

Plate heat exchanger formed, wherein the plate heat exchanger at least one in fluid communication with the jacket space first

 A heat transfer passage for receiving the first medium and having at least one second heat transfer passage in thermal contact with the first heat transfer passage, the counter force being generated by a backpressure provided in the second heat transfer passage counteracting the internal pressure. In particular, the back pressure is provided in a header of the plate heat exchanger in fluid communication with the second heat transfer passage. In this case, the liquid phase of the first medium forms during operation of the

Heat exchanger from a bath in which the plate heat exchanger is. The liquid Phase of the first medium can ascend here by means of the thermosiphon effect through the first heat transfer passage, wherein the first medium can evaporate at least partially to form a gaseous phase. In the upper region of the jacket space, this gaseous phase can collect and in particular be withdrawn from the container through a neck of the container jacket. The remaining liquid phase can sink in the shell space, re-enter the first heat transfer passage and rise again.

The heat transfer passages are formed such that heat is indirectly transferable between the first medium and the second medium. Due to the at least partial evaporation of the first medium, the second medium can be cooled during flow through the second heat transfer passage.

In particular, the plate heat exchanger has a plurality of first and second heat transfer passages, e.g. can be arranged alternately.

Further details and advantages of the invention will be explained by the following description of embodiments with reference to figures. 1 shows a schematic representation of one in a holding construction

 arranged heat exchanger,

2 is a schematic representation of a Geradrohrwärmeübertragers, Fig. 3 is a schematic representation of a wound heat exchanger,

Fig. 4 is a schematic representation of a core-in-shell heat exchanger.

1 shows a heat exchanger 1 with a container 10 for receiving a first medium M1, which has a jacket space 12 enclosed by a container jacket 11. The heat exchanger 1 further has mechanically connected components 20 with the container jacket 1 1.

In a cold stretching operation of the container shell 1 1 prevails in the shell space 12 with respect to the ambient pressure pu increased internal pressure p ,. In consequence of the Internal pressure p, the container casing 1 1 is deformed, in particular the

Wall thickness of the container shell 1 1 is reduced. It is by the

Internal pressure p, a force exerted on the components 20. FIG. 1 also shows stabilizing means 30 arranged on the components 20, which are in particular mechanically, materially and / or positively mechanically connected to the respective component 20. The heat exchanger 1 shown in Figure 1 is supported by a support structure 40, e.g. a steel structure, surrounded, where the

Stabilizing means 30 by means of brackets 41 with the support structure 40th

mechanically connected. By means of the stabilizing agent 30 is a

Counteracting force F _g exerted on the components 20, which counteracts the pressure prevailing in the shell space 12 internal pressure p, so that the components 20 by in consequence of

Internal pressure p, acting force can not be deformed. The components 20 may be e.g. to handle 20 fixed to the container shell (for example, for supplying or removing process media) or to container bottoms 20 of the container 10. Of course, it is also possible to treat only a single component 20 (e.g., nozzle or container bottom) according to the invention. FIG. 2 shows a heat exchanger 1 designed as a straight tube heat exchanger. The heat exchanger 1 has a substantially hollow-cylindrical container 10, which extends along a longitudinal axis L and has a

Container shell 1 1, which encloses a jacket space 12 for receiving a first medium M1. The container shell 1 1 further has a first

Nozzle 14 for filling the first medium M1 in the shell space 12 and a second nozzle 15 for removing the first medium M1 from the shell space 12.

Within the shell space 12, a plurality of parallel to each other along the longitudinal axis L extended tubes 50 are arranged for receiving a second medium M2, wherein the tubes 50 between two at the end faces of

Container shell 1 1 arranged tube plates 51 extend. The tubesheets 51 are mechanically connected to the container shell 1 1, in particular welded. The ends of the individual tubes 50 are respectively disposed in respective through-holes of the tubesheets 51. At the tube plates 51 close to the front side collectors 13, each forming a space for receiving a second medium M2. The two collectors 13 are in fluid communication with one another via the tubes 50, so that the second medium M2 can flow from one collector 13 through the tubes 50 into the other collector 13. The collectors 13 further have a third port 16 and a fourth

Stub 17 for filling or removal of the second medium M2.

During operation of the heat exchanger 1, heat is indirectly exchanged between the first medium M1 located in the jacket space 12 and the second medium M2 flowing through the tubes 50 in the jacket space 12.

As an alternative to the straight tube heat exchanger shown here, the

inventive method also with a straight tube heat exchanger with only one jacket space 12 on one side concluding tube plate 51, a subsequent to the tube plate 51 collector 13 and U-shaped extending through the shell space 12 tubes 50 are executed.

During a cold stretching operation of the container shell 1 1, an internal pressure p, for deforming the container shell 1 1 is applied in the shell space 12. The internal pressure p, acts in particular on the tubes 50 extending in the jacket space 12 and on the tube plates 51 closing off the jacket space 12 on both sides and exerts a force on them. In order to prevent deformation of the tubes 50 and tubesheets 51, a back pressure p _g is applied during the cold stretching operation in the collectors 13 and / or within the tubes 50, which compensates for the internal pressure p.

The internal pressure p 1 can be made available, in particular, by introducing a first fluid into the jacket space 12, for example by means of the first nozzle 14 and / or the second nozzle 15. The back pressure p _g can be provided in particular by introducing a fluid into the collector 13, for example through the third port 16 and / or the fourth port 17.

FIG. 3 shows a formed as a wound heat exchanger 1

Heat exchanger 1. The heat exchanger 1 has a along a longitudinal axis L upright arranged container 10 with a container shell 1 1, the one Jacket space 12 for receiving a first medium M1 encloses. Of the

 Container jacket 1 1 has a first port 14 for filling the first

 Medium M1 and a second nozzle 15 for withdrawing the first medium M1. In the shell space 12 a along the longitudinal axis L extended core tube 53 is arranged. On the core tube 53 a plurality of tubes 50 are helically wound, so that a tube bundle 52 is formed, which serves for receiving a second medium M2. The core tube 53 takes on the load of the tubes 50. In particular, the tubes 50 may be wound in several tube layers on the core tube 53, wherein spacers may be provided between adjacent tube layers.

During operation of the heat exchanger 1, the second medium M2 is passed through the tubes 50. In the shell space 12, heat can be exchanged between the second medium M2 and the first medium M1 located in the shell space 12.

During cold stretching of the container jacket 1 1 of the wound heat exchanger 1, an internal pressure p i is provided in the jacket space 12. To a deformation of the

Pipes 50 by the internal pressure p counteract, it can be made available in the tubes 50, a back pressure p _g . Additionally or alternatively, a back pressure p _g may be applied in the core tube 53 to prevent deformation of the core tube 53.

The internal pressure p 1 may be made available, in particular, by introducing a first fluid into the jacket space 12, for example by means of the first nozzle 14 and / or the second nozzle 15. The back pressure p _g can be realized in particular by introducing a second fluid into the tubes 50 and / or the core tube 53.

FIG. 4 schematically shows a heat exchanger 1 designed as a so-called core-in-shell heat exchanger. Such heat exchangers 1 are also referred to as block-in-shell, block-in-kettle or chain-type heat exchangers.

The heat exchanger 1 has a container 10 with a container shell 1 1, which encloses a jacket space 12 for receiving a first medium M1. Of the Container jacket 1 1 further comprises a first port 14 for filling the first medium M1 and a second port 15 for withdrawing the first medium M1.

In the shell space 12, a plate heat exchanger 60 is arranged. Of the

Plate heat exchanger 60 has a plurality of plates arranged one above the other, wherein a heat conduction structure (for example in the form of a corrugated plate), also referred to as fin, is arranged between every two adjacent plates. The plates thus define a plurality of heat transfer passages, in particular first

Heat transfer passages 61 and second heat transfer passages 62. The first heat transfer passages 61 are in flow communication with the jacket space 12, so that the first medium M1 during operation of the

Heat exchanger 1 from bottom to top through the first

Heat transfer passages 61 can flow.

The second heat transfer passages 62 are shown in the illustration with two headers 63 in fluid communication, each forming a space for receiving the second medium M2, so that by means of the header 63, the second medium M2 can be introduced into the second heat transfer passages 62 and from the second heat transfer passages 62 can be deducted.

The headers 63 are in each case connected via a connecting piece 64 with a first line 66 or via a connecting piece 65 with a second line 67 in fluid communication.

In particular, by means of the first line 66, the second medium M2 can be supplied to the second heat transfer passages 62 via the branch 64 and the header 63 and withdrawn from the second heat transfer passages 62 via the header 63 and the branch 65 by means of the second line 67.

If a first medium M1 is located in the shell space 12, the liquid phase of the first medium M1 forms, in particular, a bath in which the

Plate heat exchanger 60 is. The liquid phase of the first medium M1 can rise during operation of the heat exchanger 1 by means of the thermosyphon effect through the first heat transfer passages 61, wherein the first medium M1 can evaporate at least partially to form a gaseous phase. In the upper region of the shell space 12, this gaseous phase can collect and be withdrawn from the container 10 in particular by a nozzle, not shown here. The remaining liquid phase may drop in the shell space 12, reenter the first heat transfer passage 61, and ascend again in the first heat transfer passage 61.

The heat transfer passages 61, 62 are formed or alternately arranged such that heat is indirectly transferable between the first medium M1 and the second medium M2, when the first medium M1 is in the first

Heat transfer passages 61 is located and the second medium M2 is in the second heat transfer passages 62. Due to the at least partial evaporation of the first medium M1 while the second medium M2 at

Flow through the second heat transfer passages 62 are cooled.

During cold stretching of the container jacket 11 of the container 10 of the heat exchanger 1 shown in FIG. 4, an internal pressure p is provided in the jacket space 12. In this case, the internal pressure p, due to the existing effect

Flow connection, in particular, to the first heat transfer passages 61 of the plate heat exchanger 60 arranged in the jacket space 12. In order to counteract deformation of the plates of the plate heat exchanger 60, a back pressure p _g , which counteracts the internal pressure p, can be provided in the second heat transfer passages 62 of the plate heat exchanger 60.

The internal pressure p 1 may be made available, in particular, by introducing a first fluid into the jacket space 12, for example by means of the first nozzle 14 and / or the second nozzle 15. The back pressure p _g can be realized in particular by introducing a second fluid through the first line 66 and / or the second line 67 into the second heat transfer passages 62.

An inventive cold stretching process of a container shell 1 1 of the heat exchanger 1 shown in Figures 1 -4 is usually performed before starting the operation of the heat exchanger 1. During the cold stretching operation, therefore, there is in particular no first medium M1 in the jacket space 12 or in the first heat transfer passages 61 and no second medium M2 in the tubes 50 or in the second heat transfer passages 62. When a first fluid is used to provide the internal pressure p, this may be identical to the first medium M1 and / or the second medium M2, respectively. Alternatively, the first fluid may be a substance different from the first medium M1 and / or the second medium M2. If a second fluid is used to provide the back pressure p _g , it may be identical to the first medium M1 and / or the second medium M2. Alternatively, the first fluid may be a substance different from the first medium M1 and / or the second medium M2.

LIST OF REFERENCES

1 heat exchanger

 10 containers

 1 1 container jacket

 12 jacket space

 13 collectors

 14 First nozzle

 15 second nozzle

 16 Third nozzle

 17 Fourth nozzle

 20 component

 30 stabilizer

 40 retaining construction

 41 bracket

 50 pipe

 51 tubesheet

 52 tube bundles

 53 core tube

 60 plate heat exchangers

 61 First heat transfer passage

62 Second heat transfer passage

63 headers

 64 sockets

 65 nozzles

 66 First line

 67 Second line

 M1 First medium

 M2 second medium

 Pi internal pressure

 Pu ambient pressure

 Pg back pressure

F _q counterforce

 L longitudinal axis

Claims

claims 1 . Method for cold stretching a container casing (1 1) of a container (10) of a heat exchanger (1) for indirect heat transfer between a first medium (M1) and a second medium (M2), the container casing (1 1) at least partially forming a casing space (12 ) for receiving the first  Medium (M1) encloses, and wherein in the shell space (12) compared to the ambient pressure (pu) increased internal pressure (p,) is provided so that the container shell (1 1) by the internal pressure (p,) is cold-stretched, wherein the heat exchanger (1) has at least one component (20) which is mechanically connected to the container jacket (1 1), one component corresponding to the internal pressure (p,) counteracting counterforce (F _g ) is exerted on the at least one component (20), so that the at least one component (20) by the  Mantelraum (12) prevailing internal pressure (p,) during cold stretching of  Container shell (1 1) is not deformed. 2. The method of claim 1, wherein said counterforce (F _g ) by a  Stabilizing means (30) for a with the container shell (1 1) mechanically connected component (20) is provided, wherein the stabilizing means (30) non-positively, material and / or positively connected to the component (20). A method according to claim 1 or 2, wherein said counterforce (F _g ) is provided by means of a support structure (40), and wherein  Holding structure (40) around the entire container shell (1 1) around is arranged. 4. The method according to any one of claims 1 to 3, wherein the component (20) in  Jacket space (12) is arranged or adjacent to this. 5. The method according to any one of claims 1 to 4, wherein the component (20) a Pipe (50) is, and wherein the counterforce (F _g ) by a in the tube (50) provided back pressure (p _g ) is generated, which counteracts the internal pressure (p,). 6. The method according to any one of claims 1 to 4, wherein the component (20) is a container shell (1 1) unilaterally terminating tube plate (51), the at least one opening for connecting a in the jacket space (12) extending Pipe (50), wherein the counter-force (F _g ) by a back pressure (p _g ) is provided which acts on a side facing away from the jacket space (12) of the tube bottom (51) on the tube plate (51). The method of claim 5 or 6, wherein the tube (50) is adapted to receive the second medium (M2) so that the two media (M1, M2) can exchange heat indirectly. The method of claim 5, wherein the tube (50) is helical to an im Sheath space (12) arranged core tube (53) is wound. The method of claim 5 wherein the tube (50) is a coiled tubing core tube (53) of a coiled heat exchanger. The method of claim 1, wherein the at least one component (20) by a in the shell space (12) of the container shell (1 1) arranged Plate heat exchanger (60) is formed, wherein the A plate heat exchanger (60) having at least one first heat transfer passage (61) in fluid communication with the shell space (12) for receiving the first medium (M1) and at least one second heat transfer passage (62) in thermal contact with the first heat transfer passage (61) the counterforce (F _g ) provided by one in the second heat transfer passage (62) Counterpressure (p _g ) is generated, which counteracts the internal pressure (p,).