Adjustable injection for realizing different local refrigerant distribution

Description

[0001] The invention relates to a wound heat exchanger. Wound heat exchangers according to the preamble of claim 1 are known, for example, from document EP 3 428 563 A1.

[0002] Such coil-wound heat exchangers (CWHEs) are often used as the core of natural gas liquefaction plants. A refrigerant is added to the shell side and evaporates via a falling film. This evaporation can lead to a so-called maldistribution across the heat exchanger's tube bundle, so that some tubes in the tube bundle receive too much refrigerant, while others receive too little. This maldistribution effect can vary locally across the bundle height and thus has a negative impact of varying magnitude depending on the height.

[0003] Based on this, the present invention is therefore based on the object of providing a wound heat exchanger and a method which counteracts such performance losses.

[0004] This object is achieved by a heat exchanger having the features of claim 1 and by a method having the features of claim 12. Advantageous embodiments of these aspects of the present invention are specified in the corresponding subclaims and are described below.

[0005] According to claim 1, a heat exchanger for indirect heat transfer between a process medium and at least a first refrigerant is disclosed, comprising: a shell which surrounds a shell space and extends along a longitudinal axis, a tube bundle which is arranged in the shell space and which extends along the longitudinal axis of the shell from a lower end to an upper end of the tube bundle in the shell space, wherein the tube bundle has a plurality of first tubes for receiving the first refrigerant, which are arranged in different tube layers, wherein the first tubes are wound helically on a core tube of the heat exchanger which extends along the longitudinal axis of the shell in the shell space.

[0006] According to the invention, the first tubes each have an end formed by at least one nozzle, through which the first refrigerant, e.g., as a two-phase stream (liquid / gaseous), can be introduced or injected into the shell space. The ends are arranged along the longitudinal axis of the shell at different heights between the lower end and the upper end of the tube bundle, and the first tubes, in particular, belong to different tube layers of the tube bundle. Preferably, each first tube is arranged in a different tube layer of the tube bundle.

[0007] According to one embodiment of the heat exchanger, it is provided that the jacket space has a lower section and an upper section with respect to the longitudinal axis (in the case of the intended arrangement of the heat exchanger, in which the longitudinal axis extends along the vertical).

[0008] Furthermore, according to one embodiment of the invention, the heat exchanger comprises a first line leading into the lower section of the shell space, which is connected to each of the first tubes via a valve, so that a volume flow of the first refrigerant introduced into the respective first tube via the first line can be adjusted by means of the respective valve. Thus, said first refrigerant can be specifically injected into the shell space at different heights relative to the longitudinal axis or the vertical, as well as in the radial direction of the tube bundle in different tube layers, in order to counteract an incorrect distribution of the first refrigerant in the shell space.

[0009] Furthermore, according to an embodiment of the heat exchanger, it is provided that the tube bundle has at least one second tube which is connected to the first line, so that the first refrigerant can be introduced via the first line into the at least one second tube of the tube bundle and can be guided via this in particular from the lower section into the upper section of the jacket space, wherein the at least one second tube is fluidly connected to a second line leading out of the upper section of the jacket space, so that the first refrigerant can be withdrawn from the heat exchanger via the second line.

[0010] Furthermore, according to an alternative embodiment of the heat exchanger according to the invention, it is provided that the heat exchanger has a first line leading out of the upper section of the jacket space of the heat exchanger, which first line is connected to the first tubes in each case via a valve, so that a volume flow of the first refrigerant introduced into the respective first tube of the tube bundle via the first line can be adjusted by means of the respective valve.

[0011] Furthermore, according to one embodiment, it is preferably provided that the tube bundle has at least one second tube connected to the first line, so that the first refrigerant can be introduced into the first line via the at least one second tube, wherein the first line is connected to a second line downstream of said valves. The alternative embodiment therefore differs from the embodiment described above in particular in that the first refrigerant is fed into the first tubes from the upper section of the jacket space, whereas in the previously described embodiment it is introduced into the first tubes of the tube bundle from the lower section of the jacket space.

[0012] According to a further embodiment of the heat exchanger according to the invention, it is provided that the tube bundle has further first tubes, each of which has an end formed by at least one nozzle, via which the first refrigerant, e.g. as a two-phase flow (liquid / gaseous), can be introduced or injected into the shell space, wherein the ends of the further first tubes are also arranged along the longitudinal axis of the shell at different heights between the lower end and the upper end of the tube bundle (and wherein in particular the further first tubes belong to different tube layers), and wherein the further first tubes are each connected via a valve to the second line, which leads out of the upper section of the shell space (see above), so that a volume flow of the first refrigerant introduced via the second line into the respective further first tube can be adjusted by means of the respective valve.The present embodiment thus differs from the two alternative embodiments presented above in that the introduction of the first refrigerant into the first tubes of the tube bundle or into the further first tubes of the tube bundle takes place from the lower section of the shell space as well as from the upper section of the shell space.

[0013] According to one embodiment, the first refrigerant can be a Joule-Thomson refrigerant (JT refrigerant for short), which becomes two-phase or cools when injected into the jacket space. However, it is also possible for the first refrigerant to be a different (non-JT) refrigerant that is injected from the warm side. In the event that the first refrigerant is a JT refrigerant, according to one embodiment it is preferably provided that the second line is led back into the upper section of the jacket space via a valve, so that the first refrigerant can be introduced into the upper section of the jacket space and injected there into the upper section of the jacket space.

[0014] Furthermore, according to one embodiment of the invention, the tube bundle comprises at least one third tube for receiving a second refrigerant, wherein the second refrigerant can be guided from the lower section of the shell space into the upper section of the shell space via the at least one third tube. If the second refrigerant is not a JT refrigerant, it is then preferably withdrawn from the upper section of the shell space (as is the process medium, see below).

[0015] In the event that the first refrigerant carried in the first or further first tubes is not a JT refrigerant, the second refrigerant can, for example, be designed as a JT refrigerant.In this case, it is preferably provided according to one embodiment of the heat exchanger that the tube bundle has at least one third tube for receiving a second refrigerant, wherein the second refrigerant can be guided from the lower section of the shell space into the upper section of the shell space via the at least one third tube, and wherein the at least one third tube is fluidly connected to a further line leading out of the upper section of the shell space, so that the first refrigerant can be withdrawn from the heat exchanger via the further line, and wherein the further line is led back into the upper section of the shell space via a valve, so that the second refrigerant can be introduced into the upper section of the shell space and can be injected there into the upper section of the shell space.

[0016] In principle, one embodiment of the heat exchanger further provides that the tube bundle has at least one fourth tube for receiving the process medium to be cooled, in particular natural gas, wherein the process medium can be guided from the lower section of the shell space into the upper section of the shell space via the at least one fourth tube. Like the first or further first tubes, the second tubes, the third tubes and the fourth tubes are also preferably wound helically around the core tube of the heat exchanger. The core tube serves in particular to transfer the load of the tubes of the tube bundle. During production of the tube bundle, the tubes are wound onto the horizontally arranged core tube.

[0017] A further aspect of the present invention relates to a method for indirect heat transfer between a process medium, here preferably natural gas, and at least one first refrigerant using a heat exchanger according to the invention, wherein the first refrigerant is injected into the shell space via the nozzles of the first tubes (and optionally via the nozzles of the further first tubes).

[0018] According to an authorized embodiment of the method, it is provided that a distribution of the first refrigerant in the shell space is influenced by positioning the valves assigned to the first tubes both in the vertical direction (ie along the longitudinal axis) and in the radial direction of the tube bundle.

[0019] Furthermore, according to an embodiment of the method, it is provided that alternatively or additionally a distribution of the first refrigerant in the shell space is influenced by positioning the valves assigned to the further first tubes both in the vertical direction and in the radial direction of the tube bundle.

[0020] According to a further embodiment of the method, it is provided that an injection of the first refrigerant via the second line into the upper section of the jacket space is influenced by setting the second valve.

[0021] Further details and advantages of the invention will be explained by the following description of an embodiment with reference to the figures.

[0022] They show: Fig. 1 shows an embodiment of a heat exchanger according to the invention, wherein a first refrigerant is introduced into the shell space from below and there via ends of first tubes of the tube bundle at different heights and in different radial positions into the shell space, wherein the first refrigerant is further injected into an upper section of the shell space. Fig. 2 shows an embodiment of a heat exchanger according to the invention, wherein a first refrigerant is introduced into the shell space from below and there via ends of first tubes of the tube bundle at different heights and in different radial positions into the shell space, wherein a second refrigerant is further injected into an upper section of the shell space; Fig.3 shows an embodiment of a heat exchanger according to the invention, wherein a first refrigerant is introduced into the shell space from above and is introduced into the shell space via ends of first tubes of the tube bundle at different heights and in different radial positions, wherein the first refrigerant is further injected into an upper section of the shell space; Fig. 4 shows an embodiment of a heat exchanger according to the invention, wherein a first refrigerant is introduced into the shell space both from below and from above and is introduced into the shell space via ends of first tubes or further first tubes of the tube bundle at different heights and in different radial positions, wherein the first refrigerant is further injected into an upper section of the shell space; and Fig.5A partially sectioned view of a wound heat exchanger with a tube bundle comprising a plurality of tubes wound on a core tube, wherein an end of a first tube of the tube bundle is shown as an example, via which the first refrigerant is injected into the shell space.

[0023] Figure 1shows an embodiment of a wound heat exchanger 1 according to the invention. If such systems are used to liquefy a process medium P, in particular natural gas, the natural gas to be cooled and liquefied is located in the tube interior, i.e. in tubes 33 of a tube bundle 3 of the heat exchanger 1, in indirect heat exchange with a first refrigerant M, which flows through a jacket space 6 of the heat exchanger 1. In general, such heat exchangers 1 are oriented vertically, with the natural gas M to be cooled and liquefied flowing from bottom to top inside the tubes 33 and the first refrigerant M being distributed as evenly as possible from above in the jacket space 6. As a result of the indirect heat exchange, the temperature of the natural gas P thus decreases from bottom to top over the height of the heat exchanger, while the temperature of the first refrigerant M in the jacket space 6 increases from top to bottom to the same extent.However, due to irregularities in the distribution of the first refrigerant M to the individual tubes 33 or in the distribution of the first refrigerant M in the jacket space 6, undesirable local differences in the temperature profile between individual tubes 33 or corresponding tube layers can develop.

[0024] A continuous controllable injection to different bundle areas is now carried out, for example, according to the Fig.1The embodiment of a heat exchanger according to the invention shown is realized in that individual first tubes 31 of the tube bundle 3, which carry the first refrigerant M, are cut off at different heights and positions during winding in the bundle 3, so that these first tubes 31 each receive an open end 31a acting as a nozzle. These first tubes 31 are then connected to at least one first line 41 and connected to the main flow of the first refrigerant M by means of valves 51. In addition to the local quantitative application of the first refrigerant M via the ends 31a, the Joule-Thomson effect can also be used locally directly during injection.

[0025] Figure 1Thus, in particular, it represents an embodiment of the invention in which the first refrigerant M is used as a Joule Thomson (JT) refrigerant, which is supplied from the warm end (from below) to the first tubes 31. The ends 31a of the first tubes 31, which each preferably form at least one nozzle through which the first refrigerant M can be introduced into the shell space 6, are characterized in particular by the fact that they are arranged along the longitudinal axis z of the shell 5 of the heat exchanger 1 at different heights between a lower end 3c and an upper end 3d of the tube bundle 3 and are preferably also arranged in the radial direction R of the tube bundle 3 in different tube layers of the tube bundle. In this way, by adjusting the individual valves 51, the distribution of the first refrigerant M in the shell space 6 can be specifically influenced. The first refrigerant can, for example, be a mixture refrigerant. The first refrigerant can, for example,contain one or more of the following substances: N 2 , methane, ethane, butane, propane, pentenes. Furthermore, a third refrigerant can also be contained in the tube bundle (depending on the process application).

[0026] Again Fig. 1 As can be seen, the first line 41 is guided into a lower section 6a of the casing space 6 and is preferably connected to each first tube 31 of the tube bundle 3 via a valve 51, so that a volume flow of the first refrigerant M emerging from the respective end 31a can be separately regulated or controlled. This principle is preferably also applied to the other embodiments described below.

[0027] Furthermore, preference is given to (cf. Fig. 1), that the tube bundle 3 has at least one second tube 32 which is connected to the first line 41, so that the first refrigerant M can be introduced via the first line 41 into the at least one second tube 32 of the tube bundle 3, wherein the at least one second tube 32 is fluidly connected to a second line 42 leading out of an upper section 6b of the jacket space 6, so that the first refrigerant M can be withdrawn from the heat exchanger 1 via the second line 42, wherein the second line 42 is led back into the upper section 6b of the jacket space 6 via a valve 52, so that the first refrigerant M can be injected into the upper section 6b of the jacket space 6 in order to apply the first refrigerant M to the tube bundle 3 from above.

[0028] Furthermore, the tube bundle 3 according to Figure 1preferably at least one third tube 33 for receiving a second refrigerant M', wherein the second refrigerant M' can be guided via the at least one third tube 33 from the lower section 6a of the jacket space 6 into the upper section 6b of the jacket space 6 and can be withdrawn from the heat exchanger 1 there. The second refrigerant M' can in particular exchange heat indirectly with the process medium or natural gas P. The process medium or natural gas P can be guided via at least one fourth tube 34 of the tube bundle 3 from the lower section 6a of the jacket space 6 into the upper section 6b of the jacket space 6, from where it can be withdrawn from the heat exchanger 1. In the embodiments described herein, the heat exchanger 1 preferably has a plurality of first, further first, second, third and fourth tubes 31, 31', 32, 33, 34.The tubes 31, 31', 32, 33, 34 of the tube bundle 3 are each preferably wound helically onto a core tube 300 of the heat exchanger 300, which is shown as an example in FIG. Fig. 5 This arrangement of the tubes 31, 31', 32, 33, 34 preferably applies to all embodiments of the heat exchanger 1 described herein.

[0029] Furthermore, the Fig. 2 an embodiment of the invention in which the first refrigerant M is not the JT stream of the heat exchanger. The first refrigerant M can be a refrigerant that is only used for cooling in the liquifier or subcooler of the system. Figure 2 The first refrigerant M is introduced, which, in contrast to the Fig. 1 not a JT refrigerant, from the warm side of the heat exchanger 1. This is analogous to the Fig. 1the first refrigerant M is guided via a first line 41 into the lower section 6a of the shell space 6 and preferably connected to each first tube 31 of the tube bundle 3 via a valve 51, so that a volume flow of the first refrigerant M emerging from the respective end 31a can in turn be separately regulated or controlled. The tube bundle 3 has according to Figure 2 further comprises at least one second pipe 32 which is connected to the first pipe 41, so that the first refrigerant M can be introduced into the at least one second pipe 32 of the pipe bundle 3 via the first pipe 41, wherein the at least one second pipe 32 is fluidly connected to a second pipe 42 leading out of the upper section 6b of the casing space 6, so that the first refrigerant M can be withdrawn from the heat exchanger 1 via the second pipe 42.

[0030] Furthermore, the tube bundle 3 according to Figure 2preferably at least one third tube 33 for receiving a second refrigerant M', wherein the second refrigerant M' can be guided from the lower section 6a of the jacket space 6 into the upper section 6b of the jacket space 6 via the at least one third tube 33 and can be withdrawn from the heat exchanger 1 there. The second refrigerant M' can in particular exchange heat indirectly with the process medium or natural gas P. The process medium or natural gas P can be guided via at least one fourth tube 34 of the tube bundle 3 from the lower section 6a of the jacket space 6 into the upper section 6b of the jacket space 6, from where it can be withdrawn from the heat exchanger 1.

[0031] As further stated in the Fig. 2As can be seen, the at least one third pipe 33 for the second refrigerant M' is fluidly connected to a further line 43 leading out of the upper section 6b of the jacket space 6, so that the second refrigerant M' can be withdrawn from the heat exchanger 1 via the further line 43, wherein the further line 43 is led back into the upper section 6b of the jacket space 6 via a valve 53, so that the second refrigerant M' can be injected into the upper section 6b of the jacket space 6.

[0032] The Figure 3 shows a further embodiment of the invention, in which, in contrast to the embodiments according to the Figures 1 and 2 the supply of the first refrigerant M into the relevant bundle area between the upper end 3d and the lower end 3c takes place from above, ie from the cold side of the heat exchanger 1, whereby Fig. 3especially shows the situation where the first refrigerant M is the cold high-pressure refrigerant (from the tube side). Alternatively (not in the Fig. 3 shown), the refrigerant can also be distributed via the low-pressure side (shell side).

[0033] According to Fig. 3It is particularly provided that the tube bundle 3 of the heat exchanger 1 has at least one second tube 32, which is fed with the first refrigerant M from the lower end of the heat exchanger 1, wherein the at least one second tube 32 is guided in the shell space 6 into the upper section 6a and is connected there to a first line 41 leading out of the upper section 6a of the shell space 6, which first line 41 is in turn connected to the first tubes 31 via a valve 51, so that a volume flow of the first refrigerant M introduced into the respective first tube 31 via the first line 41 can be adjusted by means of the respective valve 51 and can be guided in the respective first tube 31 from top to bottom to the respective end 31a or nozzle 31a and can be introduced there into the shell space M. The first line 41 is further connected to a second line 42 downstream of the valves 52 or merges into this, wherein this second line 42 according to Fig. 3via a valve 52 into the upper section 6b of the shell space 6, so that the first refrigerant M can continue to be injected into the upper section 6b of the shell space 6 and can thereby be applied from above to the tube bundle 3. As already described above, the tube bundle 3 further comprises at least one third tube 33 for receiving a second refrigerant M', wherein the second refrigerant M' can be guided from the lower section 6a of the shell space 6 into the upper section 6b of the shell space 6 via the at least one third tube 33. The second refrigerant M' can thereby indirectly exchange heat with the process medium P or natural gas P, which can be guided in at least one fourth tube 34 of the tube bundle from the lower section 6a of the shell space 6 into the upper section 6b of the shell space 6 and can be withdrawn from the heat exchanger 1 there. In the embodiments according to Figures 1 to 4It is preferably provided that the process medium or natural gas P are each guided in cocurrent from bottom to top in the jacket space 6 of the heat transfer in the respective tube 33, 34 of the tube bundle 3.

[0034] Fig. 4 Finally, it shows a further development of the Figure 1shown embodiment, in which, in addition to the first tubes 31 of the tube bundle 3, further first tubes 31' of the tube bundle 3 are provided, which likewise each have an end 31'a formed by at least one nozzle through which the first refrigerant M can be introduced into the jacket space 6, wherein the ends 31'a of the further first tubes 31' are likewise arranged at different heights between the lower end 3c and the upper end 3d of the tube bundle 3 along the longitudinal axis z of the jacket 5 and are preferably also located in different tube layers. In this case, the further first tubes 31' are likewise each connected to the second line 42 via a valve 54, so that a volume flow of the first refrigerant M introduced into the respective further first tube 31' via the second line 42 can be adjusted by means of the respective valve 54.In the further first tubes 31', the first refrigerant M is guided from top to bottom in the jacket space 6. Downstream of the valves 54, the first refrigerant M can, as shown in the . Fig. 1 shown, via the second line 42 and the valve 52 into the upper section 6b of the shell space 6. The second refrigerant M as well as the process medium or natural gas P can be fed into the third and fourth tubes 33, 34 of the tube bundle 3 according to Figure 1 be conducted.

[0035] The invention can be used, for example, in a wound heat exchanger 1 according to the type of Fig. 5 be applied. As described in the Fig. 5As shown by way of example, the heat exchanger 1 has a shell 5 extending along the (vertical during operation) longitudinal axis z, which surrounds a shell space 6 of the heat exchanger 1, which serves to receive the first refrigerant M, wherein the tube bundle 3 is arranged in the shell space 6. The tube bundle 3 has a plurality of tubes 31, 32, 33, 34, which are arranged in tube layers, which are arranged one above the other in the radial direction R, starting from an innermost tube layer 3a and ending with an outermost tube layer 3b. The tubes 31, 32, 33, 34 are wound around a core tube 300 extending along the longitudinal axis z and arranged in the shell space 6, wherein in the Figure 5 exemplary embodiment according to Fig. 3 is shown, in which the first tubes 31 carry the first refrigerant M from above and inject it into the shell space. The corresponding valves and lines of the heat exchanger 1 outside the shell 5 are shown in the Fig. 5 not shown.

[0036] As in the Figure 5 As further indicated, the tubes 31, 32, 33, 34 are wound onto an outer side of the core tube 300 with webs 10 interposed therebetween. The core tube 300 thereby transfers the load of the tube bundle 3 downwards.

[0037] Furthermore, nozzles in flow connection with the jacket space 6 can be provided on the jacket 5, which serve to introduce or withdraw the first medium M. The first medium M can be guided from top to bottom or from bottom to top in the jacket space 6.

[0038] In order to prevent a bypass flow of the first medium M past the tube bundle 3 in the jacket space 6, the tube bundle 3 can be surrounded by a shirt 7. List of reference symbols 1 heat exchanger 3 Tube bundle 5 Coat 6 mantle space 3a Innermost pipe layer 6 mantle space 7 Shirt 10 web 11 gap 31 First pipe 31' Another first pipe 31a End or nozzle 32 Second pipe 33 Third pipe 34 Fourth pipe 41 First line 42 Second line 51, 52, 53, 54 valve 300 core tube M first refrigerant M' second refrigerant R Radial direction Z Axial direction or longitudinal axis P Process medium, especially natural gas

Claims

1. Heat exchanger (1) for indirect heat transfer between a process medium (P) and at least a first refrigerant (M), the heat exchanger comprising: - a shell (5) which surrounds a shell space (6) and extends along a longitudinal axis (z), - a pipe bundle (3) which is arranged in the shell space (6) and extends along the longitudinal axis (z) of the shell (5) from a lower end (3c) to an upper end (3d) of the pipe bundle (3) in the shell space (6), wherein the pipe bundle (3) has a plurality of first pipes (31) for receiving the first refrigerant (M), which first pipes are arranged in different pipe layers, wherein the first pipes (31) are wound helically onto a core pipe (300) of the heat exchanger (1), which core pipe extends along the longitudinal axis (z) of the shell (5) in the shell space (6), characterized in that the first pipes (31) each have an end (31a) which is formed by at least one nozzle via which the first refrigerant (M) can be introduced into the shell space (6), wherein the ends (31a) are arranged along the longitudinal axis (z) of the shell (5) at different heights between the lower end (3c) and the upper end (3d) of the pipe bundle (3).

2. Heat exchanger according to claim 1, characterized in that the shell space (6) has a lower portion (6a) and an upper portion (6b) relative to the longitudinal axis (z).

3. Heat exchanger according to claim 2, characterized in that the heat exchanger (1) has a first line (41) which is guided into the lower portion (6a) of the shell space (6) and is connected to the first pipes (31) via a valve (51) in each case, so that a volume flow of the first refrigerant (M) introduced into the relevant first pipe (31) via the first line (41) can be set by means of the relevant valve (51).

4. Heat exchanger according to claim 3, characterized in that the pipe bundle (3) has at least one second pipe (32) which is connected to the first line (41), so that the first refrigerant (M) can be introduced into the at least one second pipe (32) of the pipe bundle (3) via the first line (41), and wherein the at least one second pipe (32) is fluidly connected to a second line (42) leading out of the upper portion (6b) of the shell space (6), so that the first refrigerant (M) can be withdrawn from the heat exchanger (1) via the second line (42).

5. Heat exchanger according to claim 2, characterized in that the heat exchanger (1) has a first line (41) which is lead out of the upper portion (6a) of the shell space (6) and is connected to the first pipes (31) via a valve (51) in each case, so that a volume flow of the first refrigerant (M) introduced into the relevant first pipe (31) via the first line (41) can be set by means of the relevant valve (51).

6. Heat exchanger according to claim 5, characterized in that the pipe bundle (3) has at least one second pipe (32) which is connected to the first line (41), so that the first refrigerant (M) can be introduced into the first line (41) via the at least one second pipe (32), wherein the first line (41) is connected to a second line (42).

7. Heat exchanger according to claim 4, characterized in that the pipe bundle (3) has further first pipes (31'), each having an end (31a) which is formed by at least one nozzle via which the first refrigerant (M) can be introduced into the shell space (6), wherein the ends (31'a) of the further first pipes (31') are arranged along the longitudinal axis (z) of the shell (5) at different heights between the lower end (3c) and the upper end (3d) of the pipe bundle (3), and wherein the further first pipes (31') are connected to the second line (42) via a valve (54) in each case, so that a volume flow of the first refrigerant (M) introduced into the relevant further first pipe (31') via the second line (42) can be set by means of the relevant valve (54).

8. Heat exchanger according to any of claims 4, 6, 7, characterized in that the second line (42) is led back into the upper portion (6b) of the shell space (6) via a valve (52), so that the first refrigerant (M) can be injected into the upper portion (6b) of the shell space (6).

9. Heat exchanger according to claim 2 or any of claims 3 to 8 when dependent on claim 2, characterized in that the pipe bundle (3) has at least one third pipe (33) for receiving a second refrigerant (M'), wherein the second refrigerant (M') can be guided from the lower portion (6a) of the shell space (6) into the upper portion (6b) of the shell space (6) via the at least one third pipe (33).

10. Heat exchanger according to any of claims 3, 5, 7, characterized in that the pipe bundle (3) has at least one third pipe (33) for receiving a second refrigerant (M'), wherein the second refrigerant (M') can be guided from the lower portion (6a) of the shell space (6) into the upper portion (6b) of the shell space (6) via the at least one third pipe (33), and wherein the at least one third pipe (33) is fluidly connected to a further line (43) leading out of the upper portion (6b) of the shell space (6), so that the second refrigerant (M') can be withdrawn from the heat exchanger (1) via the further line (43), and wherein the further line (43) is led back into the upper portion (6b) of the shell space (6) via a valve (53), so that the second refrigerant (M') can be injected into the upper portion (6b) of the shell space (6).

11. Heat exchanger according to claim 2 or any of claims 3 to 10 when dependent on claim 2, characterized in that the pipe bundle (3) has at least one fourth pipe (34) for receiving the process medium (P) to be cooled, in particular natural gas, wherein the process medium (P) can be guided from the lower portion (6a) of the shell space (6) into the upper portion (6b) of the shell space (6) via the at least one fourth pipe (34).

12. Method for indirect heat transfer between a process medium (P) and at least one first refrigerant (M) using a heat exchanger (1) according to any of the preceding claims, wherein the first refrigerant (M) is injected into the shell space (6) via the nozzles (31a) of the first pipes (31).

13. Method according to claim 12, wherein a distribution of the first refrigerant (M) in the shell space (6) is influenced by positioning the valves (51) assigned to the first pipes (31) both in the vertical direction (z) and in the radial direction (R) of the pipe bundle (3).

14. Method according to either claim 12 or claim 13, wherein a distribution of the first refrigerant (M) in the shell space (6) is influenced by positioning the valves (54) assigned to the further first pipes (31') both in the vertical direction (z) and in the radial direction (R) of the pipe bundle (3).

15. Method according to any of claims 12 to 14, wherein an injection of the first refrigerant (M) into the upper portion (6b) of the shell space (6) via the second line (42) is influenced by positioning the second valve (52).