WITHDRAWAL/ INFEED OF GAS FOR INFLUENCING RADIAL LIQUID MIGRATION

Abstract

The invention relates to a heat exchanger for indirect heat exchange between a first medium and a second medium, comprising a shell surrounding a shell space which extends along a longitudinal axis. The shell space serves for accommodating the first medium. A tube bundle is arranged in the shell space having multiple tubes for accommodating the second medium. The tubes are helically coiled in multiple tube layers onto a core tube. The tube bundle has a multiplicity of inner tube layers, surrounding the core tube, and a multiplicity of outer tube layers, surrounding the inner tube layers. The heat exchanger discharges a part of a gaseous phase out of the shell space from the region of the inner tube layers via a gas discharge device, and/or supplies a gaseous phase into the shell space in the region of the outer tube layers via a gas supply device.

Description

The invention relates to a coiled heat exchanger according to Claim 1.

Such coiled heat exchangers are used for example in the case of physical quenches for acid gas removal (e.g. Rectisol processes), in ethylene plants or in plants for producing liquefied natural gas (LNG).

Liquid on the shell side of such heat exchangers with falling film evaporation is, in most cases, diverted in the direction of the outer tube layers of the tube bundle. This incorrect distribution of the liquid leads to a local deficit in the supply of coolant to the tube bundle in the region of the inner tube layers of the tube bundle, and therefore to losses in performance of the heat exchanger.

Taking this as a starting point, it is therefore the object of the present invention to provide a coiled heat exchanger which counteracts such performance losses.

This object is achieved by a heat exchanger having the features of claim 1 and by a method having the features of claim 14. Advantageous refinements of these aspects of the present invention are specified in the corresponding subclaims and will be described below.

According to claim 1, a heat exchanger for the indirect exchange of heat between a first medium, which has a liquid phase and a gaseous phase, and a second medium is disclosed, having

• • a shell which surrounds a shell space and which extends along a longitudinal axis, wherein the shell space serves for accommodating the first medium, and
  • a tube bundle which is arranged in the shell space and which has multiple tubes for accommodating the second medium, which tubes are helically coiled in multiple tube layers onto a core tube of the heat exchanger, which tube bundle extends along the longitudinal axis of the shell in the shell space, wherein the tube bundle has a multiplicity of inner tube layers, which surround the core tube, and a multiplicity of outer tube layers, which surround the inner tube layers and the core tube.

It is now provided according to the invention that the heat exchanger has a gas discharge device by means of which a part of the gaseous phase can be discharged out of the shell space from the region of the inner tube layers, wherein the gas discharge device of the heat exchanger has at least one discharging flow path for the gaseous phase with an inlet opening arranged in the shell space in the region of the inner tube layers, and wherein the at least one discharging flow path is formed by a tube of an inner tube layer of the tube bundle, in particular by a tube of an innermost tube layer of the tube bundle (or has such an inner or innermost tube).

Alternatively or in addition, provision is made according to the invention for the heat exchanger to have a gas supply device via which a gaseous phase of the first medium can be supplied into the shell space in the region of the outer tube layers.

The tube bundle coiled onto the core tube has, as viewed in a radial direction, a multiplicity n of tube layers situated one on top of the other, wherein, in the case of an even number n of tube layers, proceeding from the core tube, all tube layers up to the n/2-th tube layer are understood in the context of the invention to be inner tube layers, whereas the tube layers that follow these toward the outside (that is to say from the (n/2+1)-th tube layer to the n-th tube layer) are regarded as outer tube layers. In the case of an odd number of tube layers, the inner (n−1)/2 two players are understood to be inner tube layers, and the remaining tube layers are understood to be outer tube layers.

In one embodiment of the invention, the discharge of the gaseous phase takes place in the region of the innermost tube layer, and the supply of the gaseous phase takes place in the region of the outermost tube layer.

Owing to the invention, it is advantageously possible for a pressure drop in a radial direction of the tube bundle (outward toward the shell) to be reduced or avoided, such that a pressure which is as far as possible constant in a radial direction prevails in the shell space. This increases the effectiveness of the heat exchanger, because the abovementioned deflection of the liquid is reduced or avoided in this way.

In the present case, the radial direction of the tube bundle refers to a direction which is perpendicular to the longitudinal axis of the shell and which points outward toward the shell, whereas the axial direction coincides with the longitudinal axis. The core tube is preferably arranged in the shell space coaxially with respect to the longitudinal axis, and correspondingly extends in the axial direction.

The liquid phase can in a known manner be applied to the tube bundle from the top. Here, a liquid distributor used for distributing the liquid phase can also at the same time perform a separation of the liquid phase from the gaseous phase of the first medium. The separation of the liquid phase from the gaseous phase may however also be performed in separate units. The liquid distributor can conduct the liquid phase for example via an encircling gap on the shell, or via tubes, into a ring-shaped channel which is situated therebelow and which has distributor arms. Alternatively, the liquid phase can be introduced via a central opening into the core tube and then conducted to a distributor in the form of a pressure distributor. Such liquid distributors are described in detail for example in DE 10 2004 040 974 A1. Other liquid distributors are likewise conceivable.

Furthermore, in one embodiment of the heat exchanger according to the invention, it is conceivable for the at least one discharging flow path to run, at least in sections, in the core tube, for example instead of a discharging flow path, which is formed by a tube of an inner tube layer of the tube bundle, in particular by a tube of an innermost tube layer of the tube bundle (see also above).

In the case of a discharging flow path which is led at least in sections in the core tube, the inlet opening may be formed in the wall of the core tube. Alternatively, the discharging flow path may be led through a wall of the core tube, wherein the inlet opening is arranged outside the core tube in the region of the inner tube layers, or terminates flush with a surface of the wall of the core tube. Furthermore, the inlet opening may be arranged, in a radial direction of the tube bundle, between the surface of the wall of the core tube and an innermost tube layer.

It is basically possible for the at least one discharging flow path to be formed by a tube line.

Furthermore, in the case of a discharging flow path formed by a tube of an inner or of the innermost tube layer, the inlet opening may be formed in particular in a wall of the respective tube.

Furthermore, in one embodiment of the heat exchanger according to the invention, provision is made for the heat exchanger to have a skirt surrounding the tube bundle, which skirt surrounds the outer tube layers. Such a skirt may have a hollow cylindrical form and serve to prevent a bypass flow of the first medium past the tube bundle in the shell space. For this purpose, the skirt preferably engages tightly around the tube bundle.

Furthermore, in a preferred embodiment of the heat exchanger according to the invention, provision is made for the heat exchanger or the gas supply device to have, for supplying a gaseous phase of the first medium, at least one supplying flow path which has an outlet opening which is arranged in the shell space, or opens into the shell space, in the region of the outer tube layers.

In one embodiment of the heat exchanger according to the invention, provision is made here for the at least one supplying flow path to be led at least in sections on an outwardly pointing outer side of the skirt (that is to say runs further to the outside, in a radial direction, than the skirt, such that there, the skirt runs between the tube bundle and the supplying flow path) or is formed by a tube of an outer tube layer of the tube bundle, in particular by a tube of an outermost tube layer of the tube bundle (or has such an outer or outermost tube).

In the case of a supplying flow path which is led at least in sections on the outer side of the skirt, the outlet opening may be formed in the skirt. Alternatively, the supplying flow path may be led through the skirt, wherein the outlet opening may be arranged, within a shell space section surrounded by the skirt, in the region of the outer tube layers, or may terminate flush with an inner side of the skirt. Furthermore, the outlet opening may be arranged, in a radial direction of the tube bundle, between the inner side of the skirt and an outermost tube layer.

It is basically possible for the at least one supplying flow path to be formed for example by a tube line.

Furthermore, in one embodiment of the heat exchanger according to the invention, provision is made for the heat exchanger or the gas discharge device to have multiple discharging flow paths for the gaseous phase of the first medium within each case one inlet opening, wherein the inlet openings are each arranged in the shell space in the region of the inner tube layers. It is furthermore preferable for the inlet openings to be arranged at different heights along the longitudinal axis. The individual inlet openings may in this case be formed in accordance with one of the variants mentioned above.

In a further embodiment of the heat exchanger according to the invention, provision is preferably made for the heat exchanger or the gas supply device of the heat exchanger to have multiple supplying flow paths for the gaseous phase of the first medium with in each case one outlet opening, wherein the outlet openings are each arranged in the region of the outer tube layers in the shell space, and wherein, in particular, the outlet openings are arranged at different heights along the longitudinal axis.

In particular, a tube or a tube line which constitutes a discharging or a supplying flow path may have multiple inlet or outlet openings, which are for example arranged one behind the other along the respective tube or the respective tube line. In this way, it is possible in each case for a multiplicity of flow paths to the respective inlet or outlet opening to be provided by means of a single tube or a single tube line. It is self-evidently also possible for a separate tube or a separate tube line to be provided for each inlet or outlet opening.

In a further embodiment of the heat exchanger according to the invention, provision is preferably made for the heat exchanger to be designed to control the supply of the gaseous phase via the gas supply device and/or the discharge of the gaseous phase via the gas discharge device in open-loop fashion, or in closed-loop fashion in a manner dependent on an actual pressure distribution measured in the shell space or an actual temperature distribution measured in the shell space.

It is to be noted here that the temperature distribution in the shell space changes in accordance with the pressure distribution, such that the temperature distribution is also suitable for the closed-loop control of the gas discharge or supply.

In the case of closed-loop control, provision may be made in particular for the heat exchanger to control the supply and/or discharge of the gaseous phase in closed-loop fashion such that the actual pressure distribution in the shell space is approximated to a setpoint pressure distribution and/or such that the actual temperature distribution is approximated to a setpoint temperature distribution, wherein, in particular, the pressure of the setpoint pressure distribution is in each case constant in a radial direction of the tube bundle, and wherein, in particular, the temperature of the setpoint temperature distribution is in each case constant in a radial direction, specifically in particular in each case at least at a defined height of the shell space (e.g. at the level of the discharge and/or supply of the gaseous phase) or in a defined shell space section along the longitudinal axis of the shell.

In one embodiment, the heat exchanger is preferably configured such that, over the entire length of the tube bundle along the longitudinal axis, a part of the gaseous phase can be discharged from the region of the inner tube layers via a multiplicity of inlet openings, and/or the gaseous phase of the first medium can, in the region of the outer tube layers, be supplied via a multiplicity of outlet openings, such that, in particular over the entire length of the tube bundle, the actual pressure distribution or the actual temperature distribution is approximated to a setpoint pressure distribution or setpoint temperature distribution respectively, in the case of which the pressure or the temperature respectively is in each case preferably constant in a radial direction and follows a predefined or desired profile in an axial direction (that is to say along the longitudinal axis).

The heat exchanger according to the invention may have the sensors described further below for the purposes of measuring an actual pressure distribution or an actual temperature distribution.

Furthermore, in one embodiment of the heat exchanger according to the invention, provision is made for the at least one discharging flow path or the gas discharge device to have a valve for the open-loop or closed-loop control of the discharge of the gaseous phase.

In the same way, the at least one supplying flow path or the gas supply device may have a valve for the open-loop or closed-loop control of the supply of the gaseous phase.

In a further embodiment of the heat exchanger according to the invention, provision is made for the at least one discharging flow path to be connected or connectable in terms of flow via a compressor, in particular a compressor which is controllable in open-loop or closed-loop fashion, to the at least one supplying flow path. In this way, a gaseous phase discharged out of the shell space from the inner layers of the tube bundle can, after corresponding compression, be supplied to the shell space again in the region of the outer tube layers in a variable manner or in a manner controllable in open-loop or closed-loop fashion.

Furthermore, in one embodiment of the heat exchanger according to the invention, provision is made for the individual tube layers to bear against one another via spacers. The core tube preferably accommodates the load of the tubes of the tube bundle, wherein, in particular, the load of the tube layers is dissipated inward via the respective spacers.

In a further embodiment of the heat exchanger according to the invention, provision is made for the heat exchanger to have a first line, via which the first medium is introducible (in particular in two-phase form) into the heat exchanger or the shell space, and/or for the heat exchanger to have a second line, via which the first medium is withdrawable from the heat exchanger or from the shell space of the heat exchanger.

The first line may for example be connected to a connector of the heat exchanger (for example at an upper section of the heat exchanger). The second line may likewise be connected to a connector of the heat exchanger (for example at a lower section of the heat exchanger).

In a further embodiment, the heat exchanger has a first flow connection between the gas discharge device and the first line, such that a gaseous phase of the first medium or a process flow is withdrawable from the gas discharge device, and introducible into the first line, via the first flow connection.

Furthermore, in a further embodiment, the heat exchanger may also have a first flow connection between the gas discharge device and the second line, such that the a gaseous phase of the first medium or a process flow is withdrawable from the gas discharge device, and introducible into the second line, via the first flow connection.

Furthermore, in one embodiment of the invention, provision is made for the heat exchanger to have a second flow connection between the gas supply device and the first line, such that the a gaseous phase of the first medium or a process flow can be introduced from the first line into the gas supply device via the second flow connection.

Furthermore, in a further embodiment, the heat exchanger may also have a second flow connection between the gas supply device and the second line, such that a gaseous phase of the first medium or a process flow can be introduced from the second line into the gas supply device via the second flow connection.

Furthermore, in one embodiment, the first flow connection may also connect the gas discharge device to the shell space remotely from the first or second line (in particular at an arbitrary point of the shell of the heat exchanger).

Analogously to this, it is furthermore also possible, in one embodiment, for the second flow connection to connect the gas discharge device to the shell space remotely from the first or second line (in particular at an arbitrary point of the shell of the heat exchanger).

In one embodiment, it is basically possible for the first and/or the second flow connection to also have a buffer accumulator for a gaseous phase of the first medium, and in particular also a compressor and/or a valve (see also below). By means of the compressor, the first medium can be transported through the respective flow connection. The valve serves for the adjustment or interruption of the flow of the gaseous phase of the first medium.

According to a further aspect of the present invention, an industrial plant is provided which has a heat exchanger according to the invention and a first component and a first flow connection between the gas discharge device and the first component of the plant, such that a process stream of the plant (e.g. a gaseous phase of the first medium) is introducible from the gas discharge device via the flow connection into the first component. In addition or alternatively, the plant may have a second component and a second flow connection between the gas supply device and the second component, such that a process stream (e.g. a gaseous phase of the first medium) is withdrawable from the second component, and introducible into the gas supply device, via the second flow connection.

The first or the second components may each be an apparatus or a planned part of the plant in which the first medium is conducted (e.g. a gas buffer accumulator and/or a compressor) and/or treated in some other way. The first and the second component may furthermore each be a plant part or apparatus from which a gaseous phase of the first medium or a process stream is transported to the gas supply device (e.g. via a line) and/or to which a gaseous phase of the first medium is transported from the gas discharge device (e.g. via a line). The first component may be identical to the second component.

According to a further aspect of the present invention, a method for operating heat a exchanger is proposed, which method uses in particular a heat exchanger according to the invention, wherein a first medium, which has a liquid phase and a gaseous phase, is conducted in a shell space, surrounded by a shell, of the heat exchanger and indirectly exchanges heat with a second medium which is conducted in a tube bundle arranged in the shell space, which tube bundle has multiple tubes for accommodating the second medium, which tubes are helically coiled in multiple tube layers onto a core tube of the heat exchanger, which tube bundle extends along a longitudinal axis of the shell in the shell space, wherein the tube bundle has a multiplicity of inner tube layers, which surround the core tube, and a multiplicity of outer tube layers, which surround the inner tube layers and the core tube, and wherein a part of the gaseous phase is discharged out of the shell space from the region of the inner tube layers (in particular in order to lower a pressure in the shell space there), specifically in particular via the gas discharge device, and/or wherein a gaseous phase of the first medium is supplied into the shell space in the region of the outer tube layers (in particular in order to increase a pressure in the shell space there), specifically in particular via the gas supply device.

In one embodiment of the method according to the invention, provision is made for the discharge and/or the supply of the gaseous phase to be controlled in open-loop fashion, or in closed-loop fashion in a manner dependent on an actual pressure distribution or actual temperature distribution measured in the shell space (see above). The actual pressure distribution may be measured by means of a multiplicity of pressure sensors provided in the shell space, or by means of a fiber-optic sensor laid through the shell space. Here, in a known manner, effects of the pressure on a light-conducting fiber (e.g. glass fiber) are measured. Alternatively or in addition, an actual temperature distribution may be measured in the shell space by means of a fiber-optic sensor or by means of at least one light-conducting fiber (e.g. glass fiber) of a sensor of said type. It is conceivable to measure both an actual temperature distribution and an actual pressure distribution by means of a fiber-optic sensor.

In particular if an actual temperature distribution is measured by means of the fiber-optic sensor (and said actual temperature is distribution is used for the closed-loop control of the supply or discharge of the gaseous phase), the fiber-optic sensor or a light-conducting fiber, in particular glass fiber, of the sensor may be laid along the tubes of the tube bundle, such that a 3D actual temperature distribution can be measured.

In the case of closed-loop control, provision may be made in particular for the heat exchanger to control the supply and/or discharge of the gaseous phase in closed-loop fashion such that the actual pressure distribution in the shell space is approximated to a setpoint pressure distribution or such that the actual temperature distribution in the shell space is approximated to a setpoint temperature distribution, wherein, in particular, the pressure of the setpoint pressure distribution is in each case constant in a radial direction of the tube bundle, specifically in particular at least at a defined height of the shell space (e.g. at the level of the discharge and/or supply of the gaseous phase) or in a defined shell space section along the longitudinal axis of the shell. In the same way, it is in particular the case that the temperature of the setpoint temperature distribution is constant in a radial direction, specifically in particular at least at a defined height of the shell space (e.g. at the height of the discharge and/or supply of the gaseous phase) or in a defined shell space section along the longitudinal axis of the shell.

Preferably, over the entire length of the tube bundle along the longitudinal axis, a part of the gaseous phase is discharged from the region of the inner tube layers via a multiplicity of inlet openings, and/or the gaseous phase of the first medium is, in the region of the outer layers, supplied via a multiplicity of outlet openings, such that, in particular over the entire length of the tube bundle, the actual pressure distribution or the actual temperature distribution is approximated to a setpoint pressure distribution or setpoint temperature distribution respectively, in the case of which the pressure or the temperature respectively is in each case constant in a radial direction and follows a predefined profile in an axial direction (that is to say along the longitudinal axis).

Finally, according to a further aspect of the present invention, a heat exchanger for the indirect exchange of heat between a first medium, which has a liquid phase and a gaseous phase, and a second medium is disclosed, having

• • a shell which surrounds a shell space and which extends along a longitudinal axis, wherein the shell space serves for accommodating the first medium, and
  • a tube bundle which is arranged in the shell space and which has multiple tubes for accommodating the second medium, which tubes are helically coiled in multiple tube layers onto a core tube of the heat exchanger, which tube bundle extends along the longitudinal axis of the shell in the shell space, wherein the tube bundle has a multiplicity of inner tube layers, which surround the core tube, and a multiplicity of outer tube layers, which surround the inner tube layers and the core tube,
  • wherein the heat exchanger is designed to
    • discharge a part of the gaseous phase out of the shell space from the region of the inner tube layers via a gas discharge device, and/or
      • supply a gaseous phase of the first medium into the shell space in the region of the outer tube layers via a gas supply device.

A heat exchanger of said type may likewise be refined by means of the features or embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention shall be elucidated through the following figure description of an exemplary embodiment by reference to the figures, in which:

FIG. 1 shows embodiments of the heat exchanger according to the invention in which a gaseous phase is withdrawable from the shell space in the region of the innermost tube layer via the core tube;

FIG. 2 shows further embodiments of the heat exchanger according to the invention in which a gaseous phase is introducible into the shell space in the region of the outermost tube layer via the skirt;

FIG. 3 shows a further embodiment, in which both the supply and the discharge of the gaseous phase as per FIGS. 1 and 2 is possible; and

FIG. 4 shows a modification of the embodiment shown in FIG. 3;

FIG. 5 shows a perspective view of the tube bundle of the heat exchanger shown in FIGS. 1 to 4;

FIG. 6 shows a multiplicity of different embodiments with regard to flow connections of the gas supply or gas discharge device to components of the heat exchanger or of a plant in which the heat exchanger may be incorporated; and

FIG. 7 further embodiments with regard to flow connections of the gas supply or gas discharge device to components of the heat exchanger or of a plant in which the heat exchanger may be incorporated.

FIGS. 1 to 4 each show an embodiment of a coiled heat exchanger 1 according to the invention. In the respective embodiment, the coiled heat exchanger 1 has in each case a shell 5, which is preferably cylindrical at least in sections and which surrounds a shell space 6 of the heat exchanger 1, and a tube bundle 3, which is arranged in the shell space 6 and which may have multiple tubes 30 which may be helically coiled on a core tube 300, wherein the core tube 300 is arranged in particular coaxially with respect to a longitudinal axis z of the heat exchanger 1 or of the shell 5, along which longitudinal axis the shell 5 extends.

The tube 30 of the tube bundles 3 are in particular coiled helically onto the core tube 300 in multiple tube layers, wherein the individual tube layers are supported against one another by means of spacer elements 10, such that the entire weight of the tube layers can ultimately be dissipated through the core tube 300. The tube bundle 3 therefore correspondingly has, in a radial direction R, an innermost tube layer 4aa, which is arranged adjacent to the core tube 300, and an outermost tube layer 4bb in the radial direction R. The tube layers of the tube bundle 3 may in this case be divided into inner tube layers 4a and outer tube layers 4b in accordance with the definition given above.

The tube bundle 3 of FIGS. 1 to 4 may for example be formed as per FIG. 5, wherein here, for the sake of clarity, the gas discharge device 43 and the gas supply device 53 (see below) are not shown.

The said longitudinal axis z runs preferably parallel to the vertical. Furthermore, the coiled heat exchanger 1 has an in particular cylindrical skirt 7, which surrounds the tube bundle 3. Here, the skirt 7 has an inner side 7a, which faces toward the tube bundle 3, in particular the outermost tube layer 4bb, and an outer side 7b, which is averted from the inner side 7a and which faces toward the shell 5. The skirt 7 serves for preventing a bypass flow in the shell space 6 past the tube bundle 3.

A liquid phase F of a first medium M is applied to the tube bundle 3 from the top by means of a liquid distributor V, which first medium then comes into indirect heat-exchanging contact with a second medium M′ conducted in the tubes 30 of the tube bundle 3. The liquid distributor V may have multiple arms A, which are fed with liquid F for example via the core tube 300.

For the sake of clarity, the liquid distributor V is shown only in FIG. 1, but is also provided in the embodiments as per FIGS. 2 to 5 and configured in the manner of FIG. 1.

In the case of a coiled heat exchanger 1, an uneven distribution of the liquid phase F of the first medium M may arise, in the case of which the liquid phase F is forced outward toward the shell 5. This gives rise, in particular in a radial direction R of the tube bundle 3, to a pressure drop in the direction of the shell 6 or a corresponding temperature distribution, which is detrimental to the efficiency of the heat exchanger 1.

Here, the respective radial direction R is perpendicular to the longitudinal axis z or to the core tube 300, wherein the longitudinal axis z coincides with the axial direction of the tube bundle 3.

To compensate such a pressure drop of an actual pressure distribution P which is measurable in the shell space, in a first embodiment, shown in FIG. 1, of the heat exchanger 1 according to the invention, provision is made for the heat exchanger 1 to be designed to discharge a part of the gaseous phase G out of the shell space 6 from the region of the inner tube layers 4a, 4aa by means of a gas discharge device 43. Here, FIG. 1 illustrates two alternative variants, which will be described in more detail below.

In particular, in a first variant as per FIG. 1, the gas discharge device 43 of the heat exchanger 1 has at least one discharging flow path 40 for the gaseous phase G with an inlet opening 41 arranged in the shell space 6 in the region of the inner tube layers 4a, wherein, for example, the at least one discharging flow path 40 is formed by a tube 30 of an inner tube layer 4a, in particular of an innermost tube layer 4aa of the tube bundle 3.

As an alternative to this, the heat exchanger 1 or the gas discharge device 43 may, in a second variant (cf. FIG. 1), have a discharging flow path 40 for the gaseous phase G, which discharging flow path runs at least in sections in an interior space of the core tube 300 and has an inlet opening 41 arranged in the shell space 6 in the region of the inner tube layers 4a, which inlet opening is in the present case formed for example in a wall of the core tube 300.

Thus, by means of the discharging flow path 40, at least a part of the gaseous phase G of the first medium M can be withdrawn from the shell space, specifically in the present case in the region of the innermost tube layer 4aa. In this way, at the withdrawal point, that is to say at the inlet opening 41, the actual pressure distribution P generated in FIG. 1 can be generated, which has an as far as possible constant pressure in a radial direction R. Such withdrawal points or inlet openings 41 may, in FIG. 1, be provided along the entire length of the tube bundle 3 along the longitudinal axis z, in order to realize, for the entire tube bundle 3, a pressure which is as far as possible constant in a radial direction R or a temperature which is as far as possible constant in a radial direction R. Closed-loop control of the discharge of the gaseous phase G may be realized by means of a valve 8. This applies in particular both to the discharging flow path 40 which has said tube 30 of the inner or innermost tube layer 4a, 4aa (first variant), and to the discharging flow path 40 which runs at least in sections in the interior space of the core tube 300 (second variant). For the sake of simplicity, the valve 8 is shown in FIG. 1 only for the flow path 40 running in the interior space of the core tube 300.

The valve 8 is preferably adjusted such that an actual temperature distribution measured in the shell space 6 is approximated to a desired setpoint temperature distribution. Alternatively, the closed-loop control may also be performed such that a measured actual pressure distribution is approximated to a desired setpoint pressure distribution. The temperature or the pressure may be measured in the shell space for example in a known manner by means of a light-conducting fiber L or other suitable sensors (see also above). A light-conducting fiber L may for example be laid along the tubes 30, and is schematically indicated in FIG. 1.

FIG. 2 shows a modification of the embodiment shown in FIG. 1, wherein, by contrast to FIG. 1, provision is made for the gaseous phase G not to be withdrawn from the shell space 6 in the region of the inner tube layers 4a, 4aa but introduced into the shell space 6 in the region of the outer tube layers 4b, in particular in the region of the outermost tube layer 4b.

For this purpose, the heat exchanger 1 as per FIG. 2 has a gas supply device 53 with at least one supplying flow path 50 for the gaseous phase G, which in a first variant runs on the outer side 7b of the skirt 7, and within the shell space 6. It is self-evidently also conceivable for a flow path 50 of said type to be laid outside the shell 5 and to then lead through the shell 5 and the skirt 7. Furthermore, it is alternatively possible, in a second variant which is likewise shown in FIG. 2, for a flow path 50 of said type to be formed by a tube 30 of an outer tube layer 4b of the tube bundle 3, in particular by a tube 30 of an outermost tube layer 4bb of the tube bundle 3.

As shown in FIG. 2, the at least one supplying flow path 50 has an outlet opening 51 which, in the present case, is formed in the skirt 7 (or alternatively in said tube 30 of the outer or outermost tube layer 4b, 4bb), such that the introduced gaseous phase G in the present case impinges on the outermost tube layer 4bb. In this way, in particular in the region of the outer tube layers 4b, the pressure in the shell space 6 can be increased, such that, overall, a pressure P which is as far as possible constant in a radial direction R is realized as a result. Also, in FIG. 2, it is self-evidently possible for multiple inlet openings 51 to be provided along the longitudinal axis z, such that, as already described above on the basis of FIG. 1, the pressure can be positively influenced over the entire length of the tube bundle along the longitudinal axis z. Also, in FIG. 2, closed-loop control of the supply of the gaseous phase G can be performed by means of a valve 8, specifically in particular both for the supplying flow path 50 which has said tube 30 of the outer or outermost tube layer 4b, 4bb and alternatively for the supplying flow path 50 which runs on the outer side 7b of the skirt 7. For the sake of simplicity, the valve 8 is shown in FIG. 2 only for the flow path 50 running on the outer side 7b of the skirt 7.

The valve 8 is preferably adjusted such that an actual pressure distribution P measured in the shell space 6, or alternatively a measured actual temperature distribution, is approximated to a corresponding setpoint pressure distribution or setpoint temperature distribution.

Furthermore, as per FIG. 3, it is self-evidently also possible for the respective embodiments as per FIG. 1 and FIG. 2 to be combined, such that a gaseous phase G of the first medium M can be both withdrawn from and supplied to the shell space 6.

In this regard, FIG. 4 shows a modification of the embodiment shown in FIG. 3, wherein here, for the closed-loop control of the discharge of the gaseous phase G via the at least one discharging flow path 40 and for the closed-loop control of the supply of the gaseous phase G via the at least one supplying flow path 50, provision is made for the two flow paths 40, 50 to be connected in terms of flow by means of a compressor 9 which is controllable in closed-loop fashion, such that a gaseous phase G which is withdrawn from the shell space 6 in the region of the inner tube layers 4a is variably compressible by means of the compressor 9 and introducible into the shell space 6 again in the region of the outer tube layers 4b. Here, the gaseous medium G is thus conducted in a circuit. For the sake of simplicity, the compressor 9 is shown in FIG. 4 only for the flow path 40 running in the interior space of the core tube 300 and the flow path 50 running on the outer side 7b of the skirt 7, though said compressor may self-evidently also be used if the two flow paths 40, 50 are formed by a tube 30 of an inner or innermost tube layer 4a, 4aa and by a tube 30 of an outer or outermost tube layer 4b, 4bb.

Instead of closed-loop control of the supply and discharge of the gaseous phase G, it is self-evidently also possible in FIGS. 1 to 4 for open-loop control of said supply or discharge of the gaseous phase G to be provided.

Instead of additional flow paths 40, 50 which, in some embodiments as per FIGS. 1 to 4, are used in addition to the tube bundle 3 to withdraw a gaseous phase G from the shell space 6 in spatially targeted fashion or introduce a gaseous phase G into the shell space 6 in spatially targeted fashion in order to influence pressure or temperature profiles in targeted fashion, it is self-evidently basically also possible, as described above, for example, to use individual tubes 30 of the tube bundle 3 which are situated at the desired point, for example a tube 30 from the outermost tube layer 4bb for introducing the gaseous phase G or a tube 30 from the innermost tube layer 4aa for discharging gaseous phase G.

In addition to the possibilities, already presented above, of a flow connection of the gas discharge device 43 and gas supply device 53 to components of the heat exchanger 1, FIGS. 6 and 7 show further embodiments of a heat exchanger 1 according to the invention or of a plant 2 which has the heat exchanger 1, which embodiments relate to the interconnection of the gas discharge and gas supply device 43, 53.

Accordingly, as per FIG. 6, provision may be made for the heat exchanger 1 to have a first line 411, via which the first medium M on the shell side is fed (in particular in two-phase form) for example into an upper section of the heat exchanger 1 or into the shell space 6.

Furthermore, the heat exchanger 1 may have a second line 511, via which the first medium M on the shell side can be withdrawn from the shell space 6 or heat exchanger. The second line 511 may for example be provided at a lower section of the heat exchanger 1.

With regard to the line 411 or 511, provision may be made for the gas discharge device 43 to be connected via a first flow connection 410 to the first line 411, such that a part of a gaseous phase G of the first medium M can be withdrawn from the shell space 6 of the heat exchanger 1, and fed into the first line 411, via the gas discharge device 43 and the first flow connection 410.

As an alternative to this, the gas discharge device 43 may be connected via a first flow connection 410 to the second line 511, such that a part of the gaseous phase G of the first medium M can be withdrawn from the shell space 6 of the heat exchanger 1, and fed into the second line 511, via the gas discharge device 43 and the first flow connection 410.

Furthermore, it is also possible for the gas supply device 53 to be connected via a second flow connection 510 to the first line 411, such that a part of the gaseous phase G of the first medium M can be fed from the first line 411 into the gas supply device 53 via the second flow connection 510.

As an alternative to this, it is possible for the gas supply device 53 to be connected via a second flow connection 510 to the second line 511, such that a part of the gaseous phase G of the first medium M can be fed from the second line 511 into the gas supply device 53 via the second flow connection 510.

As per FIG. 6, the first and the second flow connection 410, 510 may have a gas buffer accumulator 90, a compressor 9 and in particular a valve 8, by means of which the flow of the gaseous phase G of the first medium M can be adjusted or interrupted. Here, the heat exchanger 1, together with the respective gas buffer accumulator 90, compressor 9 and valve 8, thus forms an industrial plant 2 or a part of such a plant 2, in which the first medium M constitutes a process stream. If the heat exchanger 1 or the plant 2 is, for example as per one exemplary embodiment, used for the liquefaction of natural gas, the first medium M on the shell side is a mixture of refrigerants. The first medium M may basically also be a process stream from another plant part of the plant 2.

With regard to FIG. 6, it is to be noted that, for the sake of simplicity, FIG. 6 combines different embodiments in one figure, that is to say shows all possible flow connections 410 and 510 between the gas supply and the gas discharge device 53, 43 and the first and the second line 411, 511, wherein, however, the gas discharge device 43 is in particular connected only via one of the two stated flow connections 410 to the first line 411 and to the second line 511. The same applies in particular to the gas supply device 53 with regard to the two flow connections 510 that are shown.

Furthermore, as per FIG. 7, provision may also be made for the gas discharge device 43 to be connected to the shell space 6 of the heat exchanger 1 at an arbitrary point (in particular remotely from the two lines 411, 511) via the first flow connection 410, such that the first medium M is withdrawable from the shell space 6, and introducible into the shell space 6 again, via the gas discharge device 43 (and in particular via the valve 8, the gas buffer accumulator 90 and the compressor 9). Similarly, as per FIG. 7, the gas supply device 53 may likewise be connected to the shell space 6 of the heat exchanger 1 at an arbitrary point (in particular remotely from the two lines 411, 511) via the second flow connection 510, such that the first medium M is withdrawable from the shell space 6 via the second flow connection 510 (in particular via the gas buffer accumulator 90, the compressor 9 and the valve 8), and introducible into the shell space 6 again, via the gas supply device 53. The flow connections 410, 510 shown in FIGS. 6 and 7 may self-evidently also be combined with one another in any desired manner.

If additional flow paths 40, 50 are used, the present invention has the further advantage that existing coiled heat exchangers can be particularly easily retrofitted with said flow paths 40, 50, such that, in this case, too, a performance improvement can be achieved.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

In the foregoing and in the examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.

The entire disclosures of all applications, patents and publications, cited herein and of corresponding European application No. 17020286.5, filed Jul. 10, 2017, are incorporated by reference herein.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

List of reference numerals
1       Heat exchanger
3       Tube bundle
4a, 4aa Inner tube layer
4b, 4bb Outer tube layer
5       Shell
6       Shell space
7       Skirt
7a      Inner side
7b      Outer side
8       Valve
9       Compressor
10      Spacer
30      Tubes
43      Gas discharge device
40      Discharging flow path
41      Inlet opening
53      Gas supply device
50      Supplying flow path
51      Outlet opening
300     Core tube
410     First flow connection
411     First line
510     Second flow connection
511     Second line
90      Gas buffer store
F       Liquid phase
G       Gaseous phase
M       First medium
M′      Second medium
P       Actual pressure distribution
L       Light-conducting fiber, or fiber-optic sensor
R       Radial direction
Z       Longitudinal axis

Claims

1. Heat exchanger (1) for the indirect exchange of heat between a first medium (M), which has a liquid phase (F) and a gaseous phase (G), and a second medium (W), having a shell (5) which surrounds a shell space (6) and which extends along a longitudinal axis (z), wherein the shell space serves for accommodating the first medium,a tube bundle (3) which is arranged in the shell space (6) and which has multiple tubes (30) for accommodating the second medium (M′), which tubes are helically coiled in multiple tube layers onto a core tube (300) of the heat exchanger (1), which tube bundle extends along the longitudinal axis (z) of the shell (5) in the shell space (6), wherein the tube bundle (3) has a multiplicity of inner tube layers (4a, 4aa), which surround the core tube (300), and a multiplicity of outer tube layers (4b, 4bb), which surround the inner tube layers (4a, 4aa) and the core tube (300),characterizedin that the heat exchanger (1) is designed to discharge a part of the gaseous phase (G) out of the shell space (6) from the region of the inner tube layers (4a, 4aa) via a gas discharge device (43), wherein the gas discharge device (43) of the heat exchanger (1) has at least one discharging flow path (40) for the gaseous phase (G) with an inlet opening (41) arranged in the shell space (6) in the region of the inner tube layers (4a), and wherein the at least one discharging flow path (40) is formed by a tube (30) of an inner tube layer (4a) of the tube bundle (3),and/orsupply a gaseous phase (G) of the first medium (M) into the shell space (6) in the region of the outer tube layers (4b, 4bb) via a gas supply device (53).

2. Heat exchanger according to claim 1, characterized in that the heat exchanger (1) has a skirt (7) which surrounds the tube bundle (3) and which surrounds the outer tube layers (4b, 4bb).

3. Heat exchanger according to claim 1, characterized in that the gas supply device (53) of the heat exchanger (1) has, for the gaseous phase (G), at least one supplying flow path (50) which has an outlet opening (51) arranged in the region of the outer tube layers (4b) in the shell space (6).

4. Heat exchanger according to claim 3, characterized in that the at least one supplying flow path (50) is, at least in sections, led on an outwardly pointing outer side (7b) of the skirt (7) or through a tube (30) of an outer tube layer (4b) of the tube bundle, in particular through a tube (30) of an outermost tube layer (4bb) of the tube bundle (3).

5. Heat exchanger according to claim 1, characterized in that the gas discharge device (43) of the heat exchanger (1) has multiple discharging flow paths (40) for the gaseous phase (G) of the first medium (M) with in each case one inlet opening (41), wherein the inlet openings (41) are each arranged in the shell space (6) in the region of the inner tube layers (4a), and wherein, in particular, the inlet openings (41) are arranged at different heights along the longitudinal axis (z).

6. Heat exchanger according to claim 1, characterized in that the gas supply device (53) of the heat exchanger (1) has multiple supplying flow paths (50) for the gaseous phase (G) of the first medium (M) with in each case one outlet opening (51), wherein the outlet openings (51) are each arranged in the region of the outer tube layers (4b) in the shell space (6), and wherein, in particular, the outlet openings (51) are arranged at different heights along the longitudinal axis (z).

7. Heat exchanger according to claim 1, characterized in that the heat exchanger (1) is designed to control the supply of the gaseous phase (G) via the gas supply device (53) and/or the discharge of the gaseous phase (G) via the gas discharge device (41) in open-loop fashion, or in closed-loop fashion in a manner dependent on an actual pressure distribution (P), or actual temperature distribution, measured in the shell space (6).

8. Heat exchanger according to claim 1, characterized in that the at least one discharging flow path (40) has a valve (8) for the open-loop or closed-loop control of the discharge of the gaseous phase (G), and/or in that the at least one supplying flow path (50) has a valve (8) for the open-loop or closed-loop control of the supply of the gaseous phase (G).

9. Heat exchanger according to claim 1, characterized in that the at least one discharging flow path (40) is connected in terms of flow via a compressor (9) to the at least one supplying flow path (50).

10. Heat exchanger according to claim 1, characterized in that the individual tube layers (4a, 4b) bear against one another via spacers (10).

11. Heat exchanger according to claim 1, characterized in that the core tube (300) accommodates the load of the tubes (30) of the tube bundle (3).

12. Plant (2) having a heat exchanger (1) according to claim 1, and having a first component (90) and a first flow connection (410) between the gas discharge device (43) and the first component (90) of the plant, such that a process stream (M) of the plant, which has in particular a gaseous phase (G) of the first medium (M), is introducible from the gas discharge device (41) via the flow connection (410) into the first component (90), and/or in that the plant (2) has a second component (90) and a second flow connection (510) between the gas supply device (53) and the second component (90), such that a process stream (M) of the plant (2), which has in particular a gaseous phase (G) of the first medium (M), is withdrawable from the second component (90), and introducible into the gas supply device (53), via the second flow connection (510).

13. Method for operating a heat exchanger (1) according to claim 1, wherein a first medium (M), which has a liquid phase (F) and a gaseous phase (G), is conducted in a shell space (6), surrounded by a shell (5), of the heat exchanger (1) and indirectly exchanges heat with a second medium (M′) which is conducted in a tube bundle (3) arranged in the shell space (6), which tube bundle has multiple tubes (30) for accommodating the second medium (M′), which tubes are helically coiled in multiple tube layers (4a, 4b) onto a core tube (300) of the heat exchanger (1), which tube bundle extends along a longitudinal axis (z) of the shell (5) in the shell space (6), wherein the tube bundle (3) has a multiplicity of inner tube layers (4a), which surround the core tube (300), and a multiplicity of outer tube layers (4b), which surround the inner tube layers (4a) and the core tube (300), and wherein a part of the gaseous phase (G) is discharged out of the shell space (6) from the region of the inner tube layers (4a, 4aa), and/or wherein a gaseous phase (G) of the first medium (M) is supplied into the shell space (6) in the region of the outer tube layers (4b, 4bb).

14. The method as claimed in claim 13, wherein the discharge and/or the supply of the gaseous phase (G) is controlled in open-loop fashion, or in closed-loop fashion in a manner dependent on an actual pressure distribution (P), or actual temperature distribution, measured in the shell space (6).