WOUND HEAT EXCHANGER, METHOD FOR PRODUCING A WOUND HEAT EXCHANGER AND METHOD FOR EXCHANGING HEAT BETWEEN A FIRST FLUID AND A SECOND FLUID

Abstract

The invention relates to a wound heat exchanger having a core tube extending along a longitudinal axis in an axial direction and having a tube bundle, which has a plurality of tubes for conducting a first fluid, wherein the tubes are wound about the core tube in a plurality of windings, the tubes being arranged in a radial direction perpendicular to the axial direction in a plurality of tube layers, adjacent windings of at least one tube layer having different axial distances in the axial direction and/or tube layers adjacent in the radial direction having different radial distances from each other in a cross-sectional plane perpendicular to the longitudinal axis. The invention further relates to a method for producing a wound heat exchanger and to a method for transferring heat between a first fluid and a second fluid by means of the heat exchanger.

Claims

1. A wound heat exchanger (1) having a core tube (21) extending along a longitudinal axis (L) in an axial direction (a) and having a tube bundle (2) which has a plurality of tubes (20) for conducting a first fluid, wherein the tubes (20) are wound about the core tube (21) in a plurality of windings (23), and wherein the tubes (20) are arranged in a radial direction (r) perpendicular to the axial direction (a) in a plurality of tube layers (22), wherein adjacent windings (23) of at least one tube layer (22) have different axial distances (T) in the axial direction (a), wherein the axial distances (T) of the adjacent windings (23) of said tube layer (22) grow monotonically in the axial direction (a), at least in a section of the tube bundle (2), and/or tube layers (22) adjacent to each other in the radial direction (r) have different radial distances (D) from one another in a cross-sectional plane perpendicular to the longitudinal axis (L), wherein the radial distances (D) of the adjacent tube layers (22) grow monotonically in the radial direction (r), at least in a section of the tube bundle (2).

2. The wound heat exchanger according to claim 1, wherein the windings (23) of at least one tube layer (22) have different radial distances (D) from the longitudinal axis (L) in the radial direction (r).

3. The wound heat exchanger according to claim 2, wherein the radial distances (D) of the windings (23) of said tube layer (22) from the longitudinal axis (L) grow monotonically in the axial direction (a), at least in a section of the tube bundle (2).

4. The wound heat exchanger (1) according to claim 1, wherein the tube bundle (2) has a first section (31) and a second section (32) adjacent to the first section (31) in the axial direction (a), wherein the adjacent windings (23) of said tube layer (22) in the first section (31) have an axial distance (T) which differs from an axial distance (T) of the adjacent windings (23) of said tube layer (22) in the second section (32).

5. The wound heat exchanger (1) according to claim 4, wherein said tube layer (22) has in the first section (31) a first number (n.sub.1) of windings (23), a first height (h.sub.1) extending in the axial direction (a) and a first packing density (p.sub.1), wherein the first packing density (p.sub.1) is equal to the quotient (n.sub.1/h.sub.1) of the first number (n.sub.1) and the first height (h.sub.1), and wherein said tube layer (22) has in the second section (32) a second number (n.sub.2) of windings (23), a second height (h.sub.2) extending in the axial direction (a) and a second packing density (p.sub.2), wherein the second packing density (p.sub.2) is equal to the quotient (n.sub.2/h.sub.2) of the second number (n.sub.2) and the second height (h.sub.2), and wherein the first packing density (p.sub.1) differs from the second packing density (p.sub.2).

6. The wound heat exchanger (1) according to claim 4, wherein the first section (31) is formed by a central section (35) of the tube bundle (2), wherein the second section (32) is formed by an end section (36) of the tube bundle (2).

7. The wound heat exchanger (1) according to claim 1, wherein the tube bundle (2) has an inner region (41) and an outer region (42) which surrounds the inner region (41) in a cross-sectional plane perpendicular to the longitudinal axis (L), wherein the tube layers (22) of the inner region (41) adjacent to one another in the radial direction (r) have radial distances (D) from one another in the cross-sectional plane that differ from the radial distances (D) in the cross-sectional plane between the tube layers (22) of the outer region (42) adjacent to one another in the radial direction (r).

8. The wound heat exchanger (1) according to claim 1, wherein the heat exchanger (1) has a plurality of webs (6) extending in the axial direction (a), wherein the webs (6) each form a distance in the radial direction (r) between two respective adjacent tube layers (22), wherein the webs (6) have different thicknesses (d) in the radial direction (r).

9. The wound heat exchanger (1) according to claim 8, wherein the thickness (d) of at least one of the webs (6) varies along the axial direction (r).

10. A method for producing a wound heat exchanger (1), in particular according to claim 1, wherein the tubes (20) are wound around the core tube (21) in such a way that adjacent windings (23) of at least one tube layer (22) have different axial distances (T) in the axial direction (a), and/or tube layers (22) adjacent to one another in the radial direction (r) have different radial distances (D) from one another in a cross-sectional plane perpendicular to the longitudinal axis (L).

11. A method for exchanging heat between a first fluid and a second fluid by means of a wound heat exchanger (1) according to claim 1, wherein the first fluid flows through the tubes (20) of the tube bundle (2), and wherein the second fluid is provided in a shell space (M) in which the tube bundle (2) of the heat exchanger (1) is arranged so that heat is exchanged between the first fluid and the second fluid.

12. The method for exchanging heat according to claim 11, wherein in a first section (31) of the tube bundle (2) in which turbulence or a pressure loss of the second fluid provided in the shell space (M) influences the heat exchange between the first fluid and the second fluid, the adjacent windings (23) of at least one tube layer (22) have an axial distance (T) that differs from an axial distance (T) of the adjacent windings (23) of the respective tube layer (22) in a second section (32) of the tube bundle (2) adjacent to the first section (31) in the axial direction (a), wherein in the second section (32), the turbulence or pressure loss of the second fluid causes a reduced influence on the heat exchange between the first fluid and the second fluid, wherein in particular the axial distance (T) of the adjacent windings (23) of said tube layer (22) in the first section (31) of the tube bundle (2) is smaller than the axial distance (T) of the adjacent windings (23) of said tube layer (22) in the second section (32) of the tube bundle (2).

13. The method for exchanging heat according to claim 11 or 12, wherein in a first section (31) of the tube bundle (2) in which turbulence or a pressure loss of the second fluid provided in the shell space (M) influences the heat exchange between the first fluid and the second fluid, the windings (23) of at least one tube layer (22) have a radial distance (D) from the longitudinal axis (L) that differs from a radial distance (D) of the windings (23) of the respective tube layer (22) from the longitudinal axis (L) in a second section (32) of the tube bundle (2) adjacent to the first section (31) in the axial direction (a), wherein in the second section (32), the turbulence or pressure loss of the second fluid causes a reduced influence on the heat exchange between the first fluid and the second fluid, wherein in particular the radial distance (D) of the windings (23) of said tube layer (22) from the longitudinal axis (L) in the first section (31) of the tube bundle (2) is smaller than the radial distance (D) of the windings (23) of said tube layer (22) from the longitudinal axis (L) in the second section (32) of the tube bundle (2).

Description

[0060] The Following are Shown:

[0061] FIG. 1 a partially sectional view of a wound heat exchanger;

[0062] FIG. 2 a schematic illustration of a part of a tube bundle of a wound heat exchanger according to the prior art;

[0063] FIG. 3 a schematic illustration of a part of a tube bundle of a wound heat exchanger according to this invention with different axial distances between adjacent windings;

[0064] FIG. 4 a schematic illustration of a part of a tube bundle of a wound heat exchanger according to this invention with different axial distances between adjacent windings between the central section and end section;

[0065] FIG. 5 a schematic illustration of a part of a tube bundle of a wound heat exchanger according to this invention with different radial distances between adjacent tube layers of an inner and an outer region;

[0066] FIG. 6 a schematic illustration of a part of a tube bundle of a wound heat exchanger according to this invention with different radial distances of the tube layers from the longitudinal axis.

[0067] FIG. 1 shows a wound heat exchanger 1 that has a tube bundle 2 with a plurality of tubes 20, wherein the tubes 20 run along a longitudinal axis L of the heat exchanger 1 and are helically wound around a core tube 21 or onto the core tube 21 so as to run along an imaginary helical path B indicated in FIG. 1.

[0068] In particular, the heat exchanger 1 according to the invention according to FIG. 1 has said core tube 21 onto which the tubes 20 of the tube bundle 2 are wound so that the core tube 21 bears the load of the tubes 20. However, the invention is also in principle applicable to wound heat exchangers 1 without a core tube 21 in which the tubes 20 are wound helically around the longitudinal axis L.

[0069] The heat exchanger 1 is designed for indirect heat exchange between a first and a second fluid and has a shell 10 which surrounds a shell space M for receiving the second fluid which can for example be introduced into the shell space M via an inlet connection 101 in the shell 10 and, for example, can be removed from the shell space M again via a corresponding outlet connection 102 in the shell 10. The shell 10 extends along said longitudinal axis L, which preferably runs along the vertical relative to a heat exchanger 1 arranged as intended. Furthermore, the tube bundle 2 with a plurality of tubes 20 for conducting the first fluid is arranged in the shell space M. These tubes 20 are wound helically on the core tube 21 in a plurality of tube layers 22, wherein the core tube 21 likewise also extends along the longitudinal axis L and is arranged concentrically in the shell space M.

[0070] A plurality of tubes 20 of the tube bundle 2 can each form a tube group 7 (three such tube groups 7 are shown in FIG. 1), wherein the tubes 20 of a tube group 7 can be combined in an associated tube bottom 104, wherein the first fluid can be introduced into the tubes 20 of the respective tube group 7 via inlet connections 103 in the shell 10 and removed from the tubes 20 of the corresponding tube group 7 via outlet connections 105.

[0071] Heat can thus be transferred indirectly between the two fluids. The shell 10 and the core tube 21 can furthermore be cylindrical at least in sections so that the longitudinal axis L forms a cylinder axis of the shell 10 and of the core tube 21 running concentrically therein. Furthermore, a skirt 3 which encloses the tube bundle 2 or the tubes 20 can be arranged in the shell space M so that a gap surrounding the tube bundle 2 or the tubes 20 is formed between the tube bundle 2 and said skirt 3. The skirt 3 serves where appropriate to suppress, as far as possible, a bypass flow past the tube bundle 2 of the second fluid fed to the tubes 20 and conducted in the shell space M. The second fluid is therefore conducted in the shell space M preferably in the region of the shell space M surrounded by the skirt 3. Furthermore, the individual tube layers 22 can be supported on one another or on the core tube 21 (in particular when the tube bundle 2 is mounted horizontally) via webs 6 (also referred to as spacer elements) extending along the longitudinal axis L.

[0072] FIG. 2 shows a schematic illustration of a part of a tube bundle 2 of the prior art wound around a core tube 21 in a longitudinal section. A tube layer 22 having a plurality of windings 23 is schematically illustrated. The adjacent windings 23 of the tube layer 22 all have the same axial distance T in the axial direction a. Likewise, the adjacent tube layers 22 in the radial direction r all have the same radial distance D from the longitudinal axis L.

[0073] FIG. 3 shows a schematic illustration of a part of a tube bundle 2 wound around a core tube 21 according to a first embodiment of the present invention in a longitudinal section. A tube layer 22 having a plurality of windings 23 is schematically illustrated. The adjacent windings 23 have different axial distances T from one another in the axial direction a.

[0074] Furthermore, a first section 31 and a second section 32 of the tube bundle 2 adjacent to the first section in the axial direction a are shown. The adjacent tube layers 23 of the first section 31 have greater axial distances T from one another than the adjacent tube layers 23 of the second section 32. In particular, the distances T in the axial direction a can grow monotonically from top to bottom in the vertical, for example in a section 32, 31 of the tube bundle 2 (see FIG. 3). This monotonic growth in sections can also take place from bottom to top in the vertical or along the axial direction a.

[0075] In FIG. 3, a first height h.sub.1 of the first section 31 and a second height h.sub.2 of the second section 32 are also shown. The packing density p.sub.1 of the first section 31 and the packing density p.sub.2 of the second section 32 can be calculated based on the first height h.sub.1 and the second height h.sub.2 according to the formulas p.sub.1=n.sub.1/h.sub.1 and p.sub.2=n.sub.2/h.sub.2, where n.sub.1 designates the number of windings 23 of the first section 31, and n.sub.2 the number of windings 23 of the second section 32.

[0076] In the second section 32, for example turbulence or pressure loss of the first fluid conducted in the shell space M of the heat exchanger 1 can influence the heat exchange between the first and the second fluid. This is optimized here by a more constricted tube layout, that is to say smaller axial distances T.

[0077] FIG. 4 shows the embodiment of the tube bundle 2 shown in FIG. 3, wherein a central section 33 and an end section 34 of the tube bundle 2 are identified here. In this case, the axial distances T of the adjacent windings 23 are greater in the end section 34 than in the central section 33. This can enable reduced weight for example in the end section 34, which can have, in particular, structural mechanical advantages when assembling the heat exchanger 1.

[0078] FIG. 5 shows a further embodiment of the tube bundle 2 of the heat exchanger 1 according to the invention in a cross-section with respect to the longitudinal axis L (see FIG. 1-4). The core tube 21 and the tube layers 22a, 22b, 22c, 22d, 22e are shown. Furthermore, an inner region 41 (between the core tube 21 and the inner dashed circular line) and an outer region 42 (between the inner and the outer dashed circular line) are shown. The inner region 41 runs concentrically around the core tube 21 in the shown cross-sectional plane, and the outer region 42 runs concentrically around the inner region 41 in the cross-sectional plane. In particular, the radial distances D of the adjacent tube layers 22a, 22b, 22c, 22d, 22e can grow monotonically in the radial direction r from inside to outside at least in a section of the tube bundle 2 (relative to the longitudinal axis L).

[0079] The adjacent tube layers 22a/22b and 22b/22c of the inner region 41 have a smaller radial distance D from one another in the radial direction r than the adjacent tube layers 22d/22e of the outer region 42.

[0080] FIG. 6 shows a schematic illustration of a part of a tube bundle 2 wound around a core tube 21 according to a further embodiment of the present invention in a longitudinal section. Two tube layers 22 of the tube bundle 2 adjacent to one another in the radial direction r and each having a plurality of windings 23 are schematically illustrated. The two shown tube layers 22 have different radial distances D from the longitudinal axis L (i.e., the central axis of the core tube 21) along the axial direction a, so that the tube layers 22 do not run parallel to the longitudinal axis L.

[0081] Furthermore, an optional web 6 is shown between the tube layers 22 and has a different thickness d in the radial direction r along the axial direction a (in which its longitudinal direction of extension runs). The web 6 contacts the adjacent tube layers 22 and functions as a spacer between the tube layers 22 in the radial direction r. Such a web 6 can be attached to the tube layers 22 for example by means of tack welding.

[0082] The distances between the tube layers 22 formed by the webs 6 allow a better distribution of the second fluid provided in the shell space M between the tube layers 22 so that a more effective heat exchange between the second fluid and the first fluid conducted in the tubes 20 can take place. Naturally, further webs 6 not shown here may be present.

[0083] Of course, the embodiments shown in FIG. 3/FIG. 4, FIG. 5 and FIG. 6 can also be combined with one another, i.e., both different axial distances T and different radial distances D can be provided.

LIST OF REFERENCE SIGNS

[0084]

TABLE-US-00001 1 Wound heat exchanger 2 Tube bundle 3 Skirt 6 Web 7 Tube group 20 Tube 21 Core tube 22, 22a, 22b, 22c, 22d, 22e Tube layer 23 Winding 31 First section 32 Second section 33 Central section 34 End section 41 Inner region 42 Outer region 101 Inlet connection 102 Outlet connection 103 Inlet connection 104 Tube bottom 105 Outlet connection L Longitudinal axis a Axial direction r Radial direction T Axial distance D Radial distance d Thickness M Shell space