EP3290849A1 - Heat exchanger and method for producing at least one pipe of a heat exchanger - Google Patents

Abstract

The invention relates to a heat exchanger (1) for indirect heat transfer between a first and a second fluid, with a jacket (10) surrounding a jacket space (M) for receiving the first fluid and extending along a longitudinal axis (L), and a in the jacket space (M) arranged tube bundle (2) with at least one tube (20) for receiving the second fluid, wherein the at least one tube (20) of a wall (W) enclosed interior (I), and wherein the at least one Tube (20) comprises a turbulator (200) disposed in at least a portion of the interior space (I) of the at least one tube (20), and wherein the tube (20) with the turbulator (200) disposed therein is 3D printed is formed, wherein the turbulator (200) by the 3D printing cohesively with the wall (W) of the at least one tube (20) is formed. The invention further relates to a method for producing at least one tube (20) of a heat exchanger (1).

Description

The invention relates to a heat exchanger and a method for producing at least one tube of a heat exchanger.

Coiled heat exchangers have a pressure-bearing jacket, which surrounds a jacket space for receiving a first fluid and extends along a longitudinal axis, and a core tube extending in the jacket, which extends along the longitudinal axis, which, relative to a heat exchanger arranged as intended, preferably along the Vertical runs. The heat exchanger furthermore has a tube bundle arranged in the jacket space, which tube has at least one tube and serves for receiving the second fluid, wherein this at least one tube is helically wound around the core tube.

Geradrohrwärmeübertrager also have a pressure-bearing jacket, which surrounds a jacket space for receiving a first fluid and extending along a longitudinal axis. They further have in the shell space a plurality of parallel guided along the longitudinal axis arranged tubes, which are arranged between the shell space the front end final tube sheets.

Coiled heat exchangers are currently used in various plants in the process industry, e.g. in LNG plants as natural gas liquefiers, in Rectisol plants as methanol coolers, in replacement systems of air separation plants or petrochemical plants as water bath evaporators and heat energy storage systems as molten salt heat exchangers. Water bath evaporators are designed to evaporate a guided in the tube bundle liquefied gas, wherein the tube bundle is disposed in a water bath located in the shell space.

Heretofore, in wound heat exchangers, smooth tubes are used as helically wound heat transfer surfaces.

Flow turbulators are used in straight tube heat exchangers in the process industry to improve heat transfer. Such turbulators are typically formed as bands extending along a helical path within the tubes. The heat transfer enhancement is primarily accomplished by creating a vortex flow of the tube side fluid which provides a higher velocity near the tube wall and improved fluid mixing. This results in an increase in the heat transfer coefficient and in a pressure drop.

Prior art flow turbulators are retracted into the respective tubes. This is only possible in a straight condition of the pipes. In wound heat exchangers, therefore, the tubes must be stretched before retracting the turbulators and then wound up on the core tube.

In order to allow it to be drawn into the pipes, the cross section of the turbulators must be slightly smaller than the internal cross section of the pipes. This prevents optimal geometry of the turbulators.

In addition, the turbulators may be damaged as they pass through the tubes, particularly turbulators made of reticulated material (e.g., hi-tran inserts).

By winding the tubes with turbulators inserted, it can also lead to mechanical stresses between the turbulator and inner pipe wall. Since the turbulators are usually not fixed within the tube (e.g., by welding or brazing), they can move and contract in the tube. Due to this mechanical stress, the pipes can be damaged, which in the worst case can lead to cracking of the pipes and leakage of the liquid carried in the pipe.

As a result, the object arises to provide an improved in view of the disadvantages mentioned heat exchanger with turbulators, in particular a wound heat exchanger.

This object is achieved by a heat exchanger with the features of independent claim 1 and by the manufacturing method according to independent claim 9. Advantageous embodiments of the heat exchanger are specified in the subclaims 2 to 8; advantageous embodiments of the manufacturing method are given in the subclaims 9 to 11. The embodiments will be described below.

A first aspect of the invention relates to a heat exchanger for indirect heat transfer between a first and a second fluid, the heat exchanger having a jacket which surrounds a jacket space for receiving the first fluid and extending along a longitudinal axis, and wherein the heat exchanger further in the shell space arranged tube bundle having at least one tube for receiving the second fluid, wherein the at least one tube has an inner space enclosed by a wall, and wherein the at least one tube comprises a turbulator, which is arranged in at least a portion of the interior of the at least one tube, and wherein the tube with the turbulator disposed therein is formed by 3D printing, wherein the turbulator is integrally formed by the 3D printing with the wall of the at least one tube.

Such a turbulator is configured to fluidize a flow carried in the at least one tube.

The turbulator according to the invention is made in one piece, ie integrally, with the wall of the at least one tube. The at least one tube thus has a defined internal structure, which is in constant contact with the inner tube wall.

The heat exchanger according to the invention has the advantage of a simplified manufacturing process. Thus, in a single manufacturing step, 3D printing can be used to produce tubes with integrated turbulators. These are then wound in a further step, for example, around a core tube in order to obtain a wound heat exchanger. The inclusion of the turbulators in the tubes, and thus the stretching of the tubes can be omitted.

The 3D-printed turbulators according to the invention have an increased mechanical stability and an increased service life. In particular, mechanical damage to the turbulators when they are pulled or wrapped by the turbulators integral with the tubes is avoided.

In addition, the turbulators according to the invention can be formed in any shape and arrangement and arranged in the tubes, which allows optimization of the flow guidance, heat transfer and pressure drop.

The turbulators according to the invention can also be formed of the same material as the tubes.

The at least one tube with the turbulator can be produced in particular by known 3D printing methods, such as e.g. Selective Laser Sintering (SLS), Electron Beam Melting / Electron Beam Additive Manufacturing (EBM / EBAM), Fused Filament Fabrication (FFF), Melt Stratification (eg Fused Deposition Modeling, FDM), Stereolithography (STL, SLA), Digital Light Processing (DLP) ), Multi Jet Modeling (MJM), Polyjet, Film Transfer Imaging (FTI), laser cladding, or Laminated Object Modeling (LOM).

In particular, the heat exchanger according to the invention can have both turbulators 3D-printed tubes and conventional tubes (without turbulator or with conventional turbulators). It is also conceivable that only certain pipe sections with the pipe have 3D-printed turbulators within the pipes. Other pipe sections may in particular be designed with a smooth inner wall and / or conventional turbulators (which are not printed together with the pipe 3D).

According to one embodiment, the turbulator is formed as a band extending along a helical path having first and second edges extending along the helical path, the two edges helically revolving the path, and the two edges being respectively connected to the wall of the at least one a pipe are integrally connected by the 3D printing, so that the interior is divided into two separate subspaces.

According to a further embodiment, the turbulator extends only over a portion of the at least one tube along a tube longitudinal axis in the interior of the at least one tube.

According to a further embodiment, the turbulator extends over the entire length of the at least one tube along a tube longitudinal axis in the interior of the at least one tube.

According to a further embodiment, the at least one tube is formed integrally with the turbulator by 3D printing, in particular laser sintering, of a metal, in particular aluminum.

According to a further embodiment, the at least one tube with the turbulator disposed therein by the 3D printing as a one-piece unit layers of a powdered material, in particular comprising a metal, in particular aluminum, printed, so that the turbulator cohesively with the wall of the at least one Pipe is formed, wherein successively several layers of the material are applied one above the other, each layer is heated before the application of the next following layer by means of a laser beam at a printing position corresponding to a cross-sectional area of the unit to be produced, and is thereby fixed to the underlying layer, in particular merged with this.

According to a further embodiment, the heat exchanger in the shell space on a plurality of parallel guided along the longitudinal axis of the tubes arranged, which are arranged between two the shell space frontally terminating tube sheets. Such heat exchangers are referred to as Geradrohrwärmeübertrager.

According to a further embodiment, the heat exchanger has a core tube arranged in the jacket space, which extends along the longitudinal axis, wherein the at least one tube is helically wound around the core tube. The core tube carries the load of the tube bundle. Such heat exchangers are referred to as wound heat exchangers.

According to a further embodiment, the turbulator has at least one through-hole and / or at least one projection, in particular along the pipe cross-section of the pipe, wherein the at least one through-hole and / or the at least one projection are formed together with the turbulator by the 3D printing or is. The at least one projection is formed cohesively with the turbulator.

This has the advantage that the liquid flowing through the pipe is swirled by means of the at least one through-hole and / or the at least one projection, whereby an improved heat transfer is achieved.

In particular, in the case where the turbulator is designed as a helically wound band, the at least one through-hole connects the first and second sub-spaces of the tube interior, which is formed by the turbulator.

In particular, the turbulator has a plurality of through holes and / or a plurality of projections. These may be distributed uniformly over the surface of the turbulator, or be arranged at certain particularly favorable for generating a turbulence positions.

A second aspect of the invention relates to a method for producing at least one tube of a heat exchanger, in particular according to the first aspect of the invention, wherein the at least one tube is formed together with the turbulator therein by 3D printing and thereby by the 3D printing of the turbulator cohesively connected to a wall of the at least one tube. In this case, the turbulator is formed cohesively with the wall of the at least one tube.

According to one embodiment of the method, the at least one tube is formed together with the turbulator arranged therein by 3D printing, in particular laser sintering, of a metal, in particular aluminum.

According to a further embodiment, the at least one tube, together with the turbulator disposed therein, is printed as a one-piece unit in layers of a powdered material, in particular comprising a metal, in particular aluminum, wherein successively several layers of the material be applied over each other, each layer is heated prior to the application of the next following layer by means of a laser beam at a printing position corresponding to a cross-sectional area of the unit to be produced, and is thereby fixed to the underlying layer, in particular merged with this.

The application of the layers may e.g. take place in a cross-sectional plane of the tube with turbulator, wherein successively cross-sectional layers of the tube are printed with turbulator. Alternatively, the layers may also be applied in another direction, in particular perpendicular to the cross-sectional plane, wherein the layers of at least one section of the tube are formed in the longitudinal direction of the tube.

A suitable 3D printing device has at least one laser source for generating a laser beam, a material supply for providing the material and a transport device, wherein the transport device is adapted to the workpiece, so the partially finished tube with the turbulator, against the laser source and the To move material supply and / or to move the laser source and the material supply to the workpiece.

The invention described above will now be explained in detail prior to the background in question with reference to the accompanying drawings, which show specific embodiments.

Fig. 1

einen gewickelten Wärmeübertrager,

Fig. 2

eine perspektivische Ansicht eines 3D-dedruckten Rohres mit einem stoffschlüssig mit dem Rohr verbunden Turbulator.

Show it

Fig. 1

a wound heat exchanger,

Fig. 2

a perspective view of a 3D printed pipe with a cohesively connected to the pipe turbulator.

FIG. 1 shows in connection with FIG. 2 a heat exchanger 1 according to the invention, which is characterized in that it comprises a tube bundle 2 with at least one tube 20 (see, in particular Fig. 2 ), which runs along a longitudinal axis L of the heat exchanger 1 and thereby helically wound around or on a core tube 21 of the heat exchanger 1, so that it along an imaginary Helical orbit B runs in the FIG. 1 is indicated. In the at least one tube 20 is a cohesively connected to a wall W of the tube turbulator 200 is arranged (see. FIG. 2 ), wherein the turbulator 200 is helically wound along a tube longitudinal axis I _R.

In detail, the heat exchanger 1 according to the invention FIGS. 1 and 2 said core tube 21 on which the tubes 20 of the tube bundle 2 are wound so that the core tube 21 carries the load of the tubes 20. However, the invention is also generally applicable to wound heat exchanger without core tube, in which the tubes 20 are helically wound around the longitudinal axis L. The heat exchanger 1 is designed for indirect heat transfer between a first and a second fluid and has a jacket 10 which surrounds a jacket space M for receiving the first fluid, for example via an inlet port 101 on the shell 10 in the shell space M introduced and, for example via a corresponding outlet port 102 on the jacket 10 again from the shell space M is removable.

The jacket 10 extends along the said longitudinal axis L, which preferably extends along the vertical with respect to a heat exchanger 1 arranged as intended. In the shell space M, the tube bundle 2 is further arranged with a plurality of tubes 20 for receiving the second fluid. These tubes 20 are preferably helically wound in several layers 22 on the core tube 21, wherein the core tube 21 also extends along the longitudinal axis L and is arranged concentrically in the shell space M. Several tubes 20 of the tube bundle 2 can each form a tube group (in the FIG. 1 three such pipe groups are shown), wherein the tubes of a tube group can be summarized in an associated tube plate 104, wherein the second fluid introduced via inlet ports 103 on the shell 10 in the tubes 20 of the respective tube group and outlet ports 105 from the tubes 20 of the corresponding tube group can be deducted. Thus, heat can be transferred indirectly between the two fluids.

The jacket 10 and the core tube 21 can furthermore be of cylindrical design, at least in sections, so that the longitudinal axis L forms a cylinder axis of the jacket 10 and of the concentric core tube 21 extending therein. In the shell space M, a shirt 3 can further be arranged, which the tube bundle. 2 or the at least one tube 200 encloses, so that between the tube bundle 2 and that shirt 3, a gap surrounding the tube bundle 2 or tube 200 is formed. The shirt 3 serves, if necessary, to suppress a bypass flow of the first fluid guided in the jacket space M, with which the tube bundle 2 / tube 200 is acted upon, as far as possible to suppress the tube bundle 2 / tube 200. The first fluid is thus preferably guided in the jacket space M in the region of the jacket space M surrounded by the shirt 3. Furthermore, the individual pipe layers 22 (in particular in the case of horizontal support of the tube bundle 2) can be supported on spacer elements 6 extending along the longitudinal axis L and on the core tube 21 in each case, wherein a plurality of spacer elements 6 can be arranged one above the other in the radial direction R of the tube bundle 2.

The FIG. 2 shows an approximately half-finished tube 20 of a heat exchanger 1 according to the invention during the 3D-pressure of the tube 20 together with the turbulator 200. The tube 20 has a turbulator 200, which integrally executed by 3D printing of the tube 20 together with the turbulator 200 is, wherein the turbulator 200 is materially connected to the wall W of the tube 20.

Furthermore, the shows FIG. 2 a laser source 30 for generating a laser beam 31 and a fabric feeder 40 for feeding a material 41. The laser source 30 and the fabric feeder 40 are aligned with the partially finished pipe 20 so that the material 41 at a printing position 203 on the partially completed Tube 20 can be applied, wherein the laser beam 31 is directed to the respective printing position 203, so that the material 41 is melted by means of the laser beam 31 and the material 41 is applied to the tube 20 and connected to this materially. By relative movement of the partially finished tube 20 with respect to the laser source 30 and the fabric feeder 40 (eg, the fabric feeder 40 and laser source 30 or laser beam 31 can be moved with the workpiece or tube resting), the structure of the tube may be layered 20 and the turbulator 200, so that the finished tube 20 is completely printed with the turbulator 200.

In the presentation of the FIG. 2 the tube 20 is printed in layers along with the turbulator 200, with the printed layers along the Pipe longitudinal axis I _R run. However, it is also conceivable that the printed layers run along the tube cross-section.
When the respective tube 20 with the turbulator 200 is completely printed, it is brought into its helically wound state, for example by being wound onto the core tube 21. Alternatively, the tube 20 can also be printed onto a core tube 21 or a support structure in such a way that it simultaneously receives its helical course around the core tube 21 as a result of the 3D printing. The tube 20 then no longer has to be bent or wound.

The present invention is not limited to the 3D printing technique described above, but any suitable 3D printing techniques for printing the pipe 20 with the turbulator 200 may be used.

Like in the FIG. 2 For example, the turbulator 200 may be embodied in the form of an elongated belt that is helically twisted. That is, the band 200 extends according to FIG. 2 along a pipe longitudinal axis I _R , wherein mutually opposite edges 201,202 of the belt 200 respectively helically rotate around this pipe longitudinal axis I _R. If the tube 20 is completed, the two edges 201, 202 are firmly bonded to the inside of the wall W of the tube 20 and subdivide the interior of the tube 20 into a corresponding first and a second subspace T, T '.

The turbulator 200 also has a through-hole 204 which connects the first and second sub-chambers T, T 'and thus allows the liquid flowing through the tube 20 to flow from the first sub-chamber T into the second sub-chamber T' and vice versa. This leads to a Strömungsverwirbelung, a better mixing and therefore to improved heat transfer. In particular, the turbulator 200 may include a plurality of through holes 204 that are evenly or nonuniformly distributed across the surface of the turbulator 200.

The in FIG. 2 Turbulator 200 shown further comprises a projection 205, which is in particular in the cross-sectional plane of the tube 20 extends. In the presentation of the FIG. 2 the projection 205 has a quadrangular cross-sectional area which extends in the tube cross-sectional plane. But there are also other forms conceivable. Of the Projection 205 results in a flow swirl and a better mixing of the liquid flowing through the tube 20 and therefore to an improved heat transfer. In particular, the turbulator 200 may include a plurality of protrusions 205 that are evenly or non-uniformly distributed across the surface of the turbulator 200.

If the respective tube 20 is being printed and is then wound onto the core tube 21, the tube longitudinal axis I _R (initially or before winding) has a helical course after the tube 20 has been wound onto the core tube 21, the two now Edges 201, 202 in turn run helically around this path B (see. FIG. 1 ).

Instead of in the FIG. 2 Of course, other turbulators, in particular the turbulators described herein, may also be used. <U> REFERENCE LIST </ u> Heat exchanger 1 coat 10 inlet port 101,103 outlet 102 tube sheet 104 outlet 105 tube bundle 2 pipe 20 core tube 21 pipe layer 22 turbulator 200 edge 201,202 print position 203 Through Hole 204 head Start 205 shirt 3 laser source 30 laser beam 31 fuel supply 40 material 41 spacer 6 tape B inner space I longitudinal axis L tube longitudinal axis I _R shell space M Radial direction R First subspace T Second subspace T ' wall W

Claims (11)

Heat exchanger (1) for indirect heat transfer between a first and a second fluid, with a jacket (10) surrounding a jacket space (M) for receiving the first fluid and extending along a longitudinal axis (L), a tube bundle (2) arranged in the jacket space (M) with at least one tube (20) for receiving the second fluid, wherein the at least one tube (20) has an interior space (I) enclosed by a wall (W), and wherein the at least one tube (20) has a turbulator (200) arranged in at least a portion of the interior space (I) of the at least one tube (20), characterized,
in that the tube (20) with the turbulator (200) arranged therein is formed by 3D printing, wherein the turbulator (200) is formed by the 3D printing with the wall (W) of the at least one tube (20). Heat exchanger (1) according to claim 1, characterized in that the turbulator (200) is formed as a band extending along a helical path (B) , having a first and a second edge (201, 202) extending along the helical path (B) ), wherein the two edges (201, 202) helically surround the web (B), and wherein the two edges (201, 202) are each materially bonded to the wall (W) of the at least one tube (20), so that the interior (I) is divided into two separate subspaces (T, T '). Heat exchanger (1) according to claim 1 or 2, characterized in that the turbulator (200) only over a portion of the at least one tube (20) along a pipe longitudinal axis (I _R ) in the interior (I) of the at least one tube (20). extends. Heat exchanger (1) according to claim 1 or 2, characterized in that the turbulator (200) over the entire length of the at least one tube (20) along a tube longitudinal axis (I _R ) in the interior (I) of the at least one tube (20). extends. Heat exchanger (1) according to one of the preceding claims, characterized in that the at least one tube (20) by 3D printing, in particular laser sintering, of a metal, in particular aluminum, is integrally formed with the turbulator (200). Heat exchanger (1) according to any one of the preceding claims, characterized in that the at least one tube (20) with the turbulator (200) arranged therein by the 3D printing as a one-piece unit layers of a powdery material (41), in particular having a Metal, in particular aluminum, is printed, so that the turbulator (200) is integrally formed with the wall (W) of the at least one tube (20), wherein successively several layers of the material (41) are applied one above the other, each layer before the Applying the next layer by means of a laser beam (31) at a printing position (203) corresponding to a cross-sectional area of the unit to be produced, is heated and is fixed to the underlying layer, in particular fused thereto. Heat exchanger (1) according to one of the preceding claims, characterized in that the heat exchanger (1) has a jacket tube (M) arranged in the core tube (21) which extends along the longitudinal axis (L), wherein the at least one tube (20) helically around the core tube (21) is wound. Heat exchanger (1) according to one of the preceding claims, characterized in that the turbulator (200) at least one through hole (204) and / or at least one, in particular along the tube cross-section of the tube (20) extended, projection (205), wherein the at least one through hole (204) and / or the at least one Projection (205) is formed together with the turbulator (200) by the 3D printing. Method for producing at least one tube (20) of a heat exchanger (1), in particular according to one of claims 1 to 8, wherein the at least one tube (20) together with the turbulator (200) arranged therein is formed by 3D printing and thereby the 3D printing of the turbulator (200) is materially connected to a wall (W) of the at least one tube (20). The method of claim 9, wherein the at least one tube (20) is formed together with the turbulator therein by 3D printing, in particular laser sintering, of a metal, in particular aluminum. The method of claim 9 or 10, wherein the at least one tube (20) together with the turbulator (200) arranged therein as a one-piece unit in layers of a powdery material (41), in particular comprising a metal, in particular aluminum, is printed, wherein successively a plurality of layers of the material (41) are applied to one another, wherein each layer before the application of the next following layer by means of a laser beam (31) at a printing position (203) corresponding to a cross-sectional area of the unit to be produced, and thereby fixed to the underlying layer is, in particular, merged with this.

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