Tube bundle heat exchanger with assembly / installation element formed of deflection surface and directing section - Patents.com

Abstract

The present invention relates to a tube bundle heat exchanger with built-in elements formed by deflection surfaces, windows, and directing sections. Using these built-in elements, consistent mixing of the product flow during heat transfer is achieved, thereby preventing maldistribution and axial backmixing. At the same time, the flow path is extended, thus improving heat transfer. The product flows in the outer chamber 6 of the tube bundle heat exchanger 1, which has an inlet 2 and an outlet 3 for the product and an inlet 4 and an outlet 5 for the heat carrier in the tube 7. The deflection panels or deflection surfaces 8 comprising the tube bundle heat exchanger are modified so that they leave the windows 12 and 13 open and at least one directing section 10 or 11 is attached to the inlet and outlet sides of the deflection surfaces. These directing sections extend parallel to the tube axis and intersect each other. The flow is divided by the inlet-side directing section and directed in both directions to the windows, then exits the outlet section on both sides and is deflected.

Description

[Technical field]

[0001] The present invention relates to a bundle heat exchanger comprising an assembly (which may or may not be designed as an integrated element) formed of a deflection surface and a directing section in an outer chamber according to the preamble of claim 1. [Background technology]

[0002] Because bundle heat exchangers are typically formed from metallic materials, they are often referred to as deflection panels rather than deflection surfaces, however, in this description the term deflection surfaces is used to clarify that their applicability is not limited to heat exchangers formed from metallic materials.

[0003] The bundle may consist of tubes through which a heat exchange medium (e.g. a heating or cooling medium for heating or cooling a product circulating in the outer chamber) is directed. However, other heat exchange elements combined into a bundle may alternatively be used, such as electric heating rods, electric heating coils and the like. For ease of explanation, the terms "tube" or "tube bundle" are used below, but it should be understood that in this case other elongated heat exchange elements, such as heating rods, are also meant.

[0004] The usual form of deflection panels or deflection surfaces acts as a flow guide by guiding the flow of the fluid in the outer chamber partly transversely and partly parallel to the tubes. These metal sheets have holes corresponding to the tube spacing, perpendicular to the tubes and have segment-shaped windows for the axial passage of the fluid. Other known embodiments consist of alternating disks and rings. They are installed as standard in turbulent (low viscosity fluids) and laminar (viscous fluids) flows. For further functional and structural details, see sections Gg5 and Ob7 of the VDI Heat Atlas (6th edition). These deflection surfaces improve the heat transfer thanks to a more or less pronounced cross-flow to the tubes, but do not cause any mixing of the fluid. This is especially true in the case of laminar flows of viscous fluids. These materials have a low heat transfer coefficient as a result of their properties and therefore need to be guided around the tubes (VDI Heat Atlas, section Ob4). For viscous media that need to be cooled or heated, the viscosity can vary significantly with temperature. Partial flows passing through different temperature-time histories (flow paths) end up with very different properties. This is especially true for viscosity. Without constant mixing, preferential paths and dead zones, known as maldistribution, occur. This can lead to complete failure of the heat exchanger, but also to a deterioration of product properties. The problem is similar if the heat exchanger is intended to be used as a polymerization reactor or for other exothermic reactions with viscous liquid substances. See, for example, Chemical Engineering & Technology (Chem Eng. Technol.) 13 (1990), pp. 214-220. Here again, differences in turnover and viscosity lead to maldistribution. Similar problems occur in tube bundle heat exchangers, where viscous solutions partially evaporate, in the process causing a sudden increase in viscosity.

[0005] Many static mixers, such as the X mixer (SMX, SMXL) or the helical mixer (Kenics mixer), are preferably used with laminar flow in double jacketed tubes to simultaneously improve heat transfer, mixing and residence time distribution. See Process Engineering 34 (2000) No. 1-2, pp. 18-21. There is a narrow limit to the scale-up of these devices, because the ratio of heat transfer surface to product volume decreases with increasing tube diameter, or, if the tube diameter remains the same, the pressure drop increases rapidly with increasing amounts of product. As a solution, attempts have also been made to use static mixers in the tubes of tube bundle heat exchangers, in which the product flows through the tubes. Mixing still occurs in the individual tubes, but the partial flows in the tubes are completely separated from each other, and different flow conditions and product properties can occur in the individual tubes. The result can again be a significant maldistribution in the tubes with the effects described above. This problem is further aggravated by the high pressure drop of the mixing elements. A further disadvantage for reactive products is the additional volume in the hood of the tube bundle devices. There is little or no heat transfer in this space.

[0006] German Patent No. 2839564 provides an apparatus for heat transfer and static mixing. In this mixer-heat exchanger or reactor (known as SMR reactor), the product also flows around the tubes in the outer chamber through a flow channel with a bundle of tubes. The tubes are bent in a serpentine manner to form a coiled tube. The tubes are at 45° to the flow direction and cross each other to form a mixer structure. The individual tube coils are guided outwards through the channel wall to a collector. As a result, simultaneous mixing in the outer chamber and good heat transfer are achieved, but with great effort and many drawbacks. The mixing effect is less compared to known mixers consisting of cross sections and occurs only in one direction in the bundle or mixing element. For practical reasons, the tube bundles should be as long as possible. As a result, only a few bundles that are rotated by 90° can be used in the flow channel. Each mixing element or coil bundle needs its own collector for the heat carrier. Due to the long coils and the many bends in the tubes, the pressure loss on the heat carrier side in the tubes is high. Different coil lengths can lead to uneven flow distribution on the heat carrier side, which can cause maldistribution on the product side.

[0007] Due to the structure of the bundle, favorable countercurrent flow of the heat carrier and the product or evaporation or condensation within the tubes is also not possible.

[0008] A further solution to this problem is sought in EP 1067352. Mixing elements with cross sections according to the known SMX structure are provided with holes corresponding to the tube spacing of the tube bundle heat exchanger, the tubes being inserted into the sections. Associating the mixing structure with the tube arrangement limits the freedom of tube spacing and size on the one hand and the mixer structure on the other hand. This structure is also rather weak mechanically if the sections are not rigidly connected to the tubes. From a process technology point of view, this heat exchanger may be superior to the design according to the previous paragraph, but its manufacture is very complex and demanding. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] German Patent No. 2839564 [Patent Document 2] German Patent No. 2839564 [Patent Document 3] European Patent No. 1067352 [Non-patent literature]

[0010] [Non-Patent Document 1] Chemical Engineering&Technology(ChemEng.Technol.)13(1990), pp.214-220 [Non-Patent Document 2] Process Engineering 34(2000)No.1-2, pp.18-21 Summary of the Invention [Means for solving the problem]

[0011] The object of the present invention is to provide a tube bundle heat exchanger, mixer heat exchanger or mixer reactor of the type mentioned at the beginning, which avoids the disadvantages of the prior art. This object is achieved by the characterizing features of claim 1.

[0012] The tube bundle heat exchanger according to the invention is particularly suitable for viscous products and can be manufactured very cheaply. In said tube bundle heat exchanger products can be heated, cooled or evaporated and exothermic reactions can be carried out with intensive mixing at the same time. The tube bundle heat exchanger has no moving parts due to low axial backmixing and low pressure losses. The formation of maldistribution is prevented and tools for cleaning from the outside are easily accessible if necessary. The device can also be very easily expanded. The arrangement and number of elongated (axially aligned) tubes (or other heat exchange elements) through which the flow passes can be freely selected.

[0013] Advantageous embodiments of the invention are illustrated in the accompanying drawings and are explained in more detail below. [Brief description of the drawings]

[0014] [Figure 1] 1 is a longitudinal sectional view of a tube bundle heat exchanger according to the present invention; [Diagram 2] FIG. 2 is a perspective view of the tube bundle heat exchanger. [Diagram 3] FIG. 2 is a view of the inlet side of the built-in element according to FIG. 1; [Figure 4] FIG. 2 is a view of the inlet side of the subsequent built-in element in the flow direction. [Diagram 5] FIG. 13 is an inlet side view of an alternative embodiment of an integrated element. [Figure 6] 4 shows a further embodiment of the inlet side of the built-in element. [Figure 7] 4 shows a further embodiment of the inlet side of the built-in element. [Figure 8] 4 shows a further embodiment of the inlet side of the built-in element. [Figure 9] 1A-1D are various views of an embodiment of the present invention; [Figure 10] FIG. 1 is a diagram of an embodiment of the present invention. [Figure 11] FIG. 1 is a diagram of an embodiment of the present invention. [Figure 12] FIG. 2 is a cross-sectional view of an embodiment of the present invention. [Figure 13] FIG. 2 is a cross-sectional view of an embodiment of the present invention. [Figure 14] FIG. 2 is a cross-sectional view of an embodiment of the present invention. [Figure 15] FIG. 2 is a cross-sectional view of an embodiment of the present invention. [Figure 16] FIG. 2 is a cross-sectional view of an embodiment of the present invention. [Figure 17] FIG. 17 is a perspective view of the embodiment according to FIGS. 9-16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] With general reference to the drawing, the product flows in the casing space of a tube bundle heat exchanger known per se with an inlet 2 and an outlet 3 for the product in the outer chamber 6. An inlet 4 and an outlet 5 are provided for the heat carrier flowing in the tubes 7. According to the invention, the deflection panels (or deflection faces) 8, which are usually present and are perpendicular to the axis of the tubes or heat exchanger and have holes 7' for the tubes, are modified in such a way that they leave two or more windows 12, 13 open for the axial passage of the product from the inlet side to the outlet side of the deflection face. At least one directing section 10 or 11 is attached to the inlet or outlet side. These directing sections run parallel to the tubes and divide the cross section of the tube bundle into approximately equal sized parts. If necessary, the deflection faces can also be set at an angle to the heat exchanger or tube axis (see reference number 9).

[0016] The inlet and outlet directing sections 10, 11 of the deflection surface are preferably at 90° to each other. The product flows divided in both directions by the inlet directing section 10 and flows across the tube to the window 12, 13, through which the deflection surface passes in the axial direction and opens on both sides of the outlet directing section 11 and is deflected preferably by 90° in the direction of the directing section. The flow direction of the partial flow across the tube on the outlet side is again opposite on both sides of the directing section 11. The deflection surface with the window and the intersecting directing section respectively forms an insert element A or B. The directing sections 11, 10' of successive insert elements (A, B) in the flow direction preferably intersect each other at 90°. The closed partial surfaces 8, 8' of successive insert elements A, B alternate with the windows 12, 12' and 13, 13'.

[0017] In each built-in element, the flow is split into partial flows with laminar flow and mixed so that the number of layers at each built-in element is at least doubled (with two partial flows or one directing section at the inlet and outlet side) with simultaneous intensive heat transfer. Throughout the device, the number of layers formed increases exponentially from the inlet to the outlet, and the number of built-in elements follows each other in the flow direction. This process can be demonstrated on the basis of tests with a fast-setting, robust polyester resin. In the case of turbulent flow, the turbulence leads to intensified mixing. The axial distance between successive deflection surfaces preferably corresponds to the height of two directing sections with no distance between them. However, the installation can also be made at intervals or the directing sections can be pushed together to shorten them. Instead of two windows with directing sections between the inlet and outlet side, the deflection surface can also have several windows 25, 26, 27 and many pairs of directing sections (21, 22 and 23, 24). It can also be envisaged that the number of directing sections on the inlet and outlet side or their heights are different. This increases the intensity of mixing but also increases the effort and pressure drop.

[0018] The flow path in the outer chamber is extended by the directing section according to the invention. This also increases the flow rate and the heat transfer around the tubes. The intensive mixing simultaneously prevents axial backmixing. The higher the number of successive assembly / integration elements in the heat exchanger and therefore the more streamlined the device, the narrower the residence time distribution, similar to a cascade of stirred tank reactors. In contrast to the fixture according to the invention, all already known deflection panels (or deflection surfaces) for heat exchangers do not cause any mixing in the case of laminar flows or viscous products. The heat transfer is only improved as a result of a good cross-flow to the tubes. The product flow is only diverted, not split and mixed.

[0019] FIG. 1 shows, by way of example, an integrated element A, B according to the invention formed from deflection surfaces and associated orientation sections in a U-tube heat exchanger with an extensible tube bundle. The casing 1 of the device is shown cut open in the axial direction a little forward of the center of the integrated element or in front of the orientation section 11 on the outlet side, and furthermore the integrated element is shown in the figure. The integrated element consists of closed part surfaces, windows and associated orientation sections on the inlet and outlet side. The integrated element can be loosely or fully or partly rigidly connected to the tubes by soldering, welding or gluing. The individual parts of the integrated element are also at least partially connected in this way.

[0020] In a further embodiment, the fixtures are connected to each other and to the device by holding rods, as is customary for normal deflection panels. It is also possible to manufacture the partial elements consisting of the orientation section and the closed partial surface by bending from sheet metal. The arrangement shown with the U-tube is only illustrative. Of course, the integrated element is also suitable for all other tube bundle heat exchangers, such as those with fixed straight tubes and tube sheets, or for multi-threaded devices. Non-circular (e.g. square or rectangular) device cross sections are also possible. Instead of tubes with heat carriers, electric heating rods or heating coils can also be used to heat the liquid.

[0021] 2 shows a three-dimensional view of a bundle of tubes with an installation element according to the invention, which comprises windows 12, 13, closed partial surfaces 8 and orientation sections 10, 11. The closed partial surfaces and the windows of successive installation elements respectively cover each other and successive orientation sections preferably intersect each other at an angle of 90°.

[0022] Figure 3 shows a view of the inlet side of an integrated element A according to the invention with a deflection surface 8 and two directing sections 10, 11 as well as two windows 12, 13 and holes 7' for tubes in the closed part surface. The surface area of ​​the windows usually corresponds approximately to the closed part surface. However, the windows can also be much smaller or have a different shape, such as slots or holes, in order to create special flow effects or additional pressure losses or to prevent the formation of strands.

[0023] 4 shows a view of the inlet side of the following inventive integrated element B according to the invention in the flow direction with a deflection surface 8' and two directing sections 10', 11' as well as two windows 12', 13 and holes 7' for the tubes. The closed part surfaces and the windows are offset with respect to the preceding integrated element shown in FIG.

[0024] Another embodiment is shown in figure 5. This is a view of the inlet side of an integrated element according to the invention with a deflection surface 8 with holes 7' for tubes and two orientation sections 10, 11 as well as two windows 12, 13, in this case the windows having a substantially smaller surface area than the deflection surface and of any shape.

[0025] FIG. 6 shows an inlet side view of a further integrated element according to the invention with a deflection surface 8 and four orientation sections 21, 22, 23, 24 as well as three windows 25, 26, 27 and a hole 7' for a tube.

[0026] FIG. 7 shows the inlet side of an integrated element according to the invention with a deflection surface 8 and with only one orientation section 10 on the inlet side, two orientation sections 23, 24 as well as three windows 25, 26, 27 and a hole 7' for a tube.

[0027] Figure 8 is a view of the inlet side of an integrated element according to the invention following the integrated element in front of it according to figure 7 with deflection surface 8 and with only one directing section 10' on the inlet side, two directing sections 23', 24', as well as three windows 25', 26', 27' and holes 7' for tubes. The windows are offset from each other with respect to the element according to figure 7, so that no direct axial passage is possible if the elements are placed one after the other in the flow direction.

[0028] Detailed views of the variants of the invention according to figures 7 and 8 are shown in figures 9 to 17, not all to the same scale. The casing 1 has been omitted for the sake of illustration. Figure 9 shows a plan view of a tube bundle of a heat exchanger with deflection surfaces, windows and directing sections according to the invention. The heat exchange medium (heat or coolant) flows through the tubes in the direction of the arrow 28. The directing sections are here referenced 10a to 10e. Further directing sections 10a', 10a" to 10e', 10e" are positioned at an angle of 90° thereto, said directing sections then being connected at right angles to the deflection surfaces 8a', 8a"; 8b'; 8c', 8c"; 8d'; 8e', 8e", respectively. The references 8a', 8a"; 8b'; 8c', 8c"; 8d'; 8e', 8e" indicate part surfaces with openings or holes for the tubes to pass through. The deflection surfaces are also interrupted by windows 12a'; 12b', 12b"; 12c'; 12d', 12d"; 12e'. As will be explained in more detail below, the shapes of the deflection surfaces and the windows cut by them alternate from deflection surface to deflection surface.

[0029] Figure 10 shows the same structure as Figure 9, but this time viewed in the direction of arrow X in Figure 9. Figure 11 is a plan view taken in the direction of arrow XI in Figure 9, with sections marked XII-XII and XIII-XIII, which sections can be found in Figures 12 and 13, respectively.

[0030] Also shown in Figure 9 are sections XIV-XIV, XV-XV and XVI-XVI, which are shown in Figures 14, 15 and 16, respectively. The sections show successive deflection surfaces, each having a complementary shape to the preceding (or next) deflection surface to ensure optimal mixing of the products to be mixed. The deflection surface shown in FIG. 14 therefore has (covered) partial surfaces 8a', 8a" that divert the product flow and have only one hole for the tube. Between them there is an (open) window 12a', which does not offer any resistance to the flow and is only crossed by two tubes. The deflection surface shown in FIG. 15 is complementary to the deflection surface of FIG. 14, i.e. it has a partial surface with a window located on the deflection surface of FIG. 14 and a partial surface with a window located on the deflection surface of FIG. 14. In each case the opposite applies to the lower half of the deflection surface, which is not numbered. The products flowing through the mixer / heat exchanger are therefore forced to take a different path from deflection surface to deflection surface, which results in an optimal mixing of the fluids. The third section according to FIG. 16 again corresponds to the section of FIG. 14.

[0031] For further explanation, Figure 17 is a perspective view of the tube bundle heat exchanger last described with reference to Figures 9 to 16, where arrows 28 indicate the product flow direction (see Figure 9). For clarity, reference numbers are not provided in this figure, but are derived from Figures 9 to 16.

[0032] The assembly or mounting elements and their components, such as the deflection surfaces and the directing sections, can be manufactured from steel and welded in a manner known per se. However, cast parts can also be used. Finally, manufacture from plastics can also be envisaged, for example by injection moulding or by additive manufacturing, such as 3D printing.

Claims

1. 1. A bundle heat exchanger for simultaneously supplying or dissipating heat and mixing a product flow, the bundle heat exchanger comprising: at least two bundles of elongated heat exchange elements; An outer chamber; and an inlet opening and an outlet opening, the inlet and the outlet being arranged such that product flow within the outer chamber can flow from the inlet opening to the outlet opening; at least two stationary assemblies, each of the at least two stationary assemblies including at least two partial deflection surfaces and at least two windows, each of the at least two windows being disposed within one of the partial deflection surfaces or between the partial deflection surfaces, each of the at least two windows directing the product flow from an inlet side to an outlet side of the at least two partial deflection surfaces; Including, Each of the partial deflection surfaces of each of the at least two fixing assemblies includes a first directing section and a second directing section parallel to the elongated heat exchange element, the first directing section being attached to the inlet side of the at least two partial deflection surfaces, and the second directing section being attached to the outlet side of the at least two partial deflection surfaces; the at least two partial deflection surfaces each include at least one portion without a window leading from the inlet side to the outlet side of the deflection surface, the at least one portion having one or more holes or openings for the passage of the elongated heat exchange elements according to their spacing in the bundle; A bundle heat exchanger, wherein the first directing section on the inlet side and the second directing section on the outlet side intersect each other at an angle of 90 degrees.

2. 2. The bundle heat exchanger of claim 1, wherein said bundle heat exchanger has a circular cross section.

3. 2. The bundle heat exchanger of claim 1, wherein an axial distance between successive ones of the deflection surfaces corresponds to a height of two directing sections of the first directing section and the second directing section with no distance between the two directing sections.

4. The bundle heat exchanger of claim 1 , wherein the at least two windows are disposed on opposite sides of the first directing section or disposed on opposite sides of the second directing section.

5. the at least two fastening assemblies include a first fastening assembly and a second fastening assembly; the deflection surfaces of the first and second stationary assemblies stand transversely to the elongated heat exchange element, the deflection surfaces of the first and second stationary assemblies being arranged one behind the other in a flow direction; the windows of the deflection surface of the first fixation assembly alternate with the at least one portion of the deflection surface of the second fixation assembly that does not include a window; The bundle heat exchanger of claim 1 , wherein the at least one portion of the deflection surface of the first stationary assembly that does not include a window alternates with the windows of the deflection surface of the second stationary assembly.

6. the deflection surfaces of the first and second stationary assemblies each include the first and second orientation sections; 6. The bundle heat exchanger of claim 5, wherein the first or second directing section of the first stationary assembly intersects with the first or second directing section of the second stationary assembly at a 90° angle.

7. 2. The bundle heat exchanger of claim 1, wherein the cross section of the bundle is divided into partial surfaces of approximately equal size by the first and second orientation sections of the stationary assembly.

8. 2. The bundle heat exchanger of claim 1, wherein for at least one of the deflection surfaces, a portion having the at least two windows leading from the inlet side to the outlet side is smaller than the at least one portion having no window leading from the inlet side to the outlet side.

9. 13. A method comprising the step of operating the bundle heat exchanger of claim 1 for heat transfer with a viscous product.

10. 13. A method comprising the step of operating the bundle heat exchanger of claim 1 as a reactor in an exothermic or endothermic reaction.

11. The bundle heat exchanger of claim 1 , wherein a number of the first directing sections and the second directing sections differs between the inlet side and the outlet side.

12. The bundle heat exchanger of claim 1 , wherein heights of the first directing section and the second directing section are different on the inlet side and the outlet side.

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