heat exchange tubes

Abstract

This solves the problem of inefficient heat exchange using conventional heat exchange tubes. [Solution] The invention comprises a tube and a porous layer, wherein the tube has a plurality of ribs, the plurality of ribs extending along the axial direction of the tube and forming the inner circumferential wall of the tube, the porous layer has a plurality of pores, the porous layer is located at least on the plurality of ribs, the porous layer has a first layer and a second layer, the first layer covers the plurality of ribs, the second layer is located on the surface of the first layer, and the average pore diameter of the plurality of pores in the second layer is greater than the average pore diameter of the plurality of pores in the first layer. According to the present invention, the efficiency of heat exchange can be increased.

Description

Technical Field

[0001] The present invention relates to a heat exchange tube for performing heat exchange, and particularly to a heat exchange tube used in a reboiler to vaporize a processing liquid by heat exchange.

Background Art

[0002] A reboiler is a heating facility that is widely used in the petrochemical industry and is mainly used for product purification. Briefly speaking, the reboiler is installed at the bottom of a distillation kettle and is used to heat the processing fluid in the distillation kettle. As a result, the processing fluid vaporizes to form rising steam, and a predetermined component is separated from the processing fluid by the phase change of the processing fluid. And the reboiler has a heat exchange tube, which is also called a high flux tube, and the processing fluid can pass through the heat exchange tube to perform the above phase change.

[0003] Specifically, a heat source can supply heat to the heat exchange tube from the outside of the heat exchange tube. When the heat is transmitted to the inner pipe wall of the heat exchange tube, the processing fluid can contact the inner pipe wall of the heat exchange tube to perform heat exchange, thereby causing a phase change to generate steam. However, in the conventional heat exchange tube, only by contacting the processing fluid with the inner pipe wall can the purpose of heat exchange be achieved. Therefore, the heat exchange efficiency of the conventional heat exchange tube is not good.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Based on the above problems, it is necessary to further improve the above-mentioned conventional heat exchange tube.

[0006] To solve the above problems, the object of the present invention is to provide a heat exchange tube that can have relatively good heat exchange efficiency. [Means for solving the problem]

[0007] The terms of directionality or similar terms used throughout the specification of this invention, such as "front," "back," "left," "right," "top," "bottom," "inside," "outside," and "side," primarily indicate direction on the accompanying drawings. Each of these terms is intended to aid in the explanation and understanding of each embodiment of the invention and does not limit the invention.

[0008] The use of the counter words "one" or "one" for parts and components described throughout the specification of this invention is merely for convenience and provides the usual meaning within the scope of this invention, and should be interpreted as including one or at least one; and the concept of a line segment also includes multiple cases, excluding those that clearly represent other meanings.

[0009] Throughout the text of this invention, approximate terms such as "joining," "combining," or "assembling" primarily include configurations in which the members can still be separated without being destroyed after joining, or in which the members cannot be separated after joining, and which can be selected by those with ordinary skill in the art depending on the material of the members to be joined or the requirements of the assembly.

[0010] The heat exchange tube of the present invention comprises a tube body and a porous layer, wherein the tube body has a plurality of ribs, the plurality of ribs extending along the axial direction of the tube body and forming the inner circumferential wall of the tube body, the porous layer has a plurality of pores, the porous layer is located at least on the plurality of ribs, the porous layer has a first layer and a second layer, the first layer covers the plurality of ribs, the second layer is located on the surface of the first layer, and the average pore diameter of the plurality of pores in the second layer is greater than the average pore diameter of the plurality of pores in the first layer.

[0011] As a result, in the heat exchange tube of the present invention, since the inner circumferential wall of the tube body has the plurality of ribs, the processing fluid forms a relatively large contact area with the inner circumferential wall of the tube body, and as the processing fluid flows into the tube body, it can collide with the plurality of ribs and generate turbulence, and the residence time in the tube body can be made relatively long. Furthermore, the plurality of ribs further have the first layer and the second layer in order, and the average hole diameter of the plurality of pores in the second layer is larger than the average hole diameter of the plurality of pores in the first layer, so that the phase change of the processing fluid can be easily caused by the small holes in the first layer, and the large holes in the second layer are made into gas-liquid exchange passages, so that vaporized gas bubbles can leave the second layer even more quickly, and the processing fluid can enter the space of the first layer quickly, thereby increasing the efficiency of heat exchange.

[0012] Furthermore, the material of the tube contains 75-95% by weight of copper and 5-25% by weight of nickel. This allows the tube to have better corrosion resistance.

[0013] Furthermore, each of the ribs has opposing side walls, and each rib has a thickness between the side walls, with two adjacent ribs having a first thickness and a second thickness, and the ratio of the first thickness to the second thickness is 1:1 to 3. As a result, multiple ribs of various thicknesses can be formed on the inner circumferential wall of the pipe, so that after the processing fluid hits the multiple ribs, it can form an even more irregular flow.

[0014] Furthermore, each of the ribs has opposing side walls, each rib has a thickness between the side walls, two adjacent ribs have a first thickness and a second thickness, there is a gap between two adjacent ribs, and the sum of the first and second thicknesses is twice the gap. This allows the processing fluid to form an even more irregular flow after it strikes the multiple ribs.

[0015] Furthermore, a recess is formed between two adjacent ribs, and the two adjacent ribs have a first and second protrusion height relative to the recess, with the ratio of the first to the second protrusion height being 1:1 to 4. As a result, multiple ribs with various protrusion heights can be formed on the inner circumferential wall of the pipe, thereby preventing the processing fluid from flowing smoothly into the pipe.

[0016] Furthermore, a recess is formed between two adjacent ribs, and the two adjacent ribs have a first and second protrusion height relative to the recess, respectively. The recess has a radial thickness in the pipe body, and the sum of the first and second protrusion heights is three times the radial thickness. This allows the processing fluid to form an even more irregular flow after it strikes the multiple ribs.

[0017] Furthermore, the total thickness of the porous layers is 0.125 to 0.3 times the wall thickness of the tube. This prevents the combined thickness of the first porous layer and the second porous layer from becoming excessive, thereby preventing a decrease in heat conduction efficiency.

[0018] Furthermore, the wall thickness of the tube is 1 to 3 mm. This allows heat to easily pass through the wall of the tube and be conducted into the tube.

[0019] Furthermore, the first layer is formed by mixing a first metal powder with a binder and sintering it, and the second layer is formed by mixing a second metal powder with the binder and sintering it, wherein the average particle size of the first metal powder is smaller than the average particle size of the second metal powder. As a result, the first layer and the second layer can form a two-layer porous structure on the inner wall of the tube, with pores ranging from small to large in sequence.

[0020] Further, the binder is selected from the group consisting of polypropylene, polyethylene, polystyrene, polyethylene terephthalate, polymethacrylic acid, acetone, and xylene. Thereby, since the binder can be used as a carrier for collecting the metal powder, it can help to apply the metal powder to the inner wall of the tube body.

[0021] Further, the first metal powder contains 75 to 95% by weight of copper and 5 to 25% by weight of nickel. Thereby, the first layer and the inner wall of the tube body 1 can have better bonding properties.

[0022] Further, the second metal powder contains 75 to 95% by weight of copper and 5 to 25% by weight of nickel. Thereby, the second layer and the first layer can have better bonding properties.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view of the first embodiment of the present invention. [Figure 2] It is an end view of the first embodiment of the present invention. [Figure 3] It is an enlarged view of part A in FIG. 2. [Figure 4] It is an end view of the second embodiment of the present invention.

Best Mode for Carrying Out the Invention

[0024] In order to further clarify and make the above and other objects, features, and advantages of the present invention more understandable, the embodiments of the present invention will be described in detail below with reference to the drawings. In addition, the same reference numerals in different drawings are regarded as the same, and the description thereof will be omitted.

[0025] As shown in FIGS. 1 and 2, in the first embodiment of the heat exchange tube of the present invention, it includes a tube body 1 and a porous layer 2, and the porous layer 2 is located on the inner wall of the tube body 1.

[0026] The tube 1 is surrounded by an annular wall to form a space S, allowing the processing fluid to absorb heat from outside the tube 1 through heat conduction within the space S and perform heat exchange. The wall thickness of the tube 1 may be 1 to 3 mm, and the tube 1 may be a straight or curved tube. Furthermore, the cross-section of the tube 1 may have a geometric shape such as a circle or a square, and is not limited to these in the present invention. The material of the tube 1 may be a metal material that is advantageous for conducting heat into the tube 1. For example, the material of the tube 1 may be a copper alloy such as red copper, cupronickel, or brass, or a material with thermal conductivity such as iron or an iron alloy. Preferably, the material of the tube 1 contains at least 75% by weight of copper to form good thermal conductivity. In this embodiment, since the material of the tube 1 is a copper-nickel alloy, the tube 1 has relatively good corrosion resistance and can be applied to most chemical liquids. The copper-nickel alloy may contain 75 to 95% by weight of copper and 5 to 25% by weight of nickel.

[0027] As shown in Figures 2 and 4, the pipe body 1 has a plurality of ribs 11, which are located in the space S, and the plurality of ribs 11 extend along the axial direction of the pipe body 1 and are formed on the inner circumferential wall of the pipe body 1. As a result, the plurality of ribs 11 allow the processing fluid to form a relatively large contact area with the inner circumferential wall of the pipe body 1, resulting in better heat exchange efficiency. In addition, as the processing fluid flows into the pipe body 1, it can collide with the plurality of ribs 11, generating turbulence, which increases the residence time in the pipe body 1, thereby increasing the heat exchange rate. The plurality of ribs 11 may be distributed over the entire inner circumferential wall of the pipe body 1, or they may be distributed over a part of the inner circumferential wall of the pipe body 1 (as shown in Figure 4), and the present invention is not limited thereto.

[0028] As shown in Figure 3, in the radial direction of the pipe body 1, each rib 11 has opposing side walls 12, and each rib 11 has a thickness between the side walls, which can be 0.5 to 3 mm. Furthermore, two adjacent ribs 11 can each have a first thickness W1 and a second thickness W2. For example, the first thickness W1 and the second thickness W2 can be the same, and a plurality of ribs 11 of the same specification can be formed on the inner circumferential wall of the pipe body 1, making it easy to manufacture the pipe body 1. Alternatively, the first thickness W1 and the second thickness W2 can be different, preferably the ratio of the first thickness W1 to the second thickness W2 can be 1:1 to 3. As a result, a plurality of ribs 11 with various thicknesses can be formed on the inner circumferential wall of the pipe body 1, so that after the processing fluid hits the plurality of ribs 11, it can form an irregular flow, and the processing fluid can increase the residence time of the processing fluid in the pipe body 1 by hindering the smooth flow of the processing fluid in the pipe body 1. Preferably, there can be a maximum spacing W3 between two adjacent ribs 11. For example, if the cross-section of the pipe 1 is circular, the maximum spacing W3 can be the distance between two adjacent ribs 11 in the circumferential direction, and if the cross-section of the pipe 1 is rectangular, the maximum spacing W3 can be the distance between two adjacent ribs 11 in the linear direction perpendicular to the side walls 12. The sum of the first thickness W1 and the second thickness W2 can be 1 to 2 times the maximum spacing W3. In this way, the irregularity of the flow after the processing fluid strikes the plurality of ribs 11 can be further increased.

[0029] In addition, since a recess 13 is formed between two adjacent ribs 11, the two adjacent ribs 11 can have a first protrusion height H1 and a second protrusion height H2 with respect to the recess 13, and the first protrusion height H1 and the second protrusion height H2 can be 1 to 4 mm. For example, the first protrusion height H1 and the second protrusion height H2 can be the same, and the inner circumferential wall of the pipe body 1 can form multiple ribs 11 of a single specification, making it easy to manufacture the pipe body 1. Alternatively, the first protrusion height H1 and the second protrusion height H2 can be different, preferably the ratio of the first protrusion height H1 to the second protrusion height H2 can be 1:1 to 4. As a result, multiple ribs 11 of various thicknesses can be formed on the inner circumferential wall of the pipe body 1, and the residence time of the processing fluid in the pipe body 1 can be increased by further hindering the smooth flow of the processing fluid in the pipe body 1. Preferably, the recess 13 has a radial thickness H3 in the pipe body 1, and the sum of the first protrusion height H1 and the second protrusion height H2 can be 2 to 5 times the radial thickness H3. This allows the processing fluid to form an even more irregular flow after it strikes the plurality of ribs 11.

[0030] As shown in Figures 2 and 3, the porous layer 2 can be located on the inner circumferential wall of the pipe body 1, that is, the porous layer 2 can cover the plurality of ribs 11. Furthermore, if the plurality of ribs 11 are distributed on a portion of the inner circumferential wall of the pipe body 1, the porous layer 2 can simultaneously cover the plurality of ribs 11 and the wall surface without the plurality of ribs 11. More specifically, the porous layer 2 has a first layer 21, the first layer 21 has a first average thickness D1, and the first average thickness D1 can be 0.1 to 0.6 mm. In another embodiment, the first average thickness D1 can be 0.1 mm. The first layer 21 can be formed by sintering a first metal powder, for example, by mixing the first metal powder with a binder to form a slurry, the binder being selected from the group consisting of polypropylene (PP), polyethylene (PE), polystyrene, polyethylene terephthalate (PET), polymethacrylic acid, acetone, and xylene. The binder can be used as a carrier for collecting the metal powder. Thus, the slurry can be applied to the inner circumferential wall of the tube 1, then sintered to form the first layer 21, and the first layer 21 is formed to have multiple pores due to the gaps between each metal particle in the first metal powder.

[0031] Furthermore, since the metal particles of the first layer 21 have a particle size of 25 to 150 μm, the average pore size of the multiple pores in the first layer 21 can be 18 to 110 μm. The first metal powder can be sintered onto the inner wall of the tube body 1 so as to cover the multiple ribs 11. The first metal powder may be a copper alloy such as red copper, cupronickel, or brass, or a powder of iron or an iron alloy. In this embodiment, the first metal powder may be a copper-nickel alloy powder containing 75 to 95% by weight of copper and 5 to 25% by weight of nickel. As a result, the first layer 21 and the tube body 1 can be made of the same material, and thus the first layer 21 and the inner wall of the tube body 1 can have better bonding properties.

[0032] The porous layer 2 has a second layer 22, which is located on the inner surface of the first layer 21, and the second layer 22 has a second average thickness D2, which can be 0.18 to 0.72 mm. In another embodiment, the second average thickness D2 can be 0.18 mm. The total thickness of the first layer 21 and the second layer 22 is D1 + D2, and the relationship with the wall thickness of the tube 1, i.e., the radial thickness H3, can be 0.125H3 ≤ D1 + D2 ≤ 0.3H3, which prevents the total thickness of the first layer 21 and the second layer 22 from becoming excessive, thus preventing a decrease in the efficiency of heat conduction.

[0033] The second layer 22 can be formed by sintering a second metal powder in the manner described above, and the second layer 22 has multiple pores due to the gaps between each metal particle in the second metal powder. It should be noted that the average pore diameter of the multiple pores in the second layer 22 is larger than the average pore diameter of the multiple pores in the first layer 21, and furthermore, the metal particles in the second layer 22 can have a particle size of 45 to 180 μm, and the average pore diameter of the multiple pores in the second layer 22 can be 30 to 125 μm. In this embodiment, the second metal powder may be a copper-nickel alloy powder containing 75 to 95% by weight of copper and 5 to 25% by weight of nickel, thereby allowing the second layer 22 and the first layer 21 to have relatively better bonding properties.

[0034] In addition, the porosity of the pores in the first layer 21 and the pores in the second layer 22 can be the same or different, and can be adjusted according to the type of processing fluid, thereby producing the best phase change effect for each type of processing fluid. For example, the porosity of the first layer 21 can be 60.3%, and the porosity of the second layer 22 can be 35.73%. In yet another embodiment, the porosity of the first layer 21 can be 59.8%, and the porosity of the second layer 22 can be 34.9%. Thus, the porosity of the pores in the first layer 21 and / or the second layer 22 can be adjusted by adding a pore-forming agent. The pore-forming agent is selected from, but is not limited to, the group consisting of, for example, iron(II) sulfate, iron(III) sulfate, Mackinawite, marcasite, pyrite, troilite, pyrrhotite, greigite, amorphous iron(II) sulfide, lead sulfide, coal, silicon dioxide, sodium silicate, sodium oxide, calcium oxide, magnesium oxide, potassium hydroxide, sodium hydroxide, ammonium nitrate, and potassium sulfate.

[0035] As a result, the first layer 21 and the second layer 22 can form a two-layer porous structure on the inner wall of the pipe body 1, with pore sizes ranging from small to large in sequence. When the processing fluid comes into contact with the second layer 22 inside the pipe body 1, the second layer 22 has pores with relatively large diameters, allowing multiple fluid molecules of the processing fluid to easily enter the pores of the second layer 22. Furthermore, since the first layer 21 has pores with relatively small diameters, multiple fluid molecules of the processing fluid can each enter into the pores of the first layer 21, forming small particle molecules, which makes it easier for a phase change to occur after heat exchange. In addition, the first layer 21 can be formed with a relatively large total surface area by metal particles with relatively small particle sizes, thus providing a better heat exchange effect. After these fluid molecules vaporize, the relatively large pores of the second layer 22 allow these vaporized molecules to easily separate, thus enabling the pores of the first layer 21 to quickly allow other liquid molecules to enter, thereby improving the efficiency of the phase change.

[0036] In summary, according to the heat exchange tube of the present invention, since the inner circumferential wall of the tube has the plurality of ribs, the processing fluid forms a relatively large contact area with the inner circumferential wall of the tube, and as the processing fluid flows into the tube, it can collide with the plurality of ribs to generate turbulence, and the residence time in the tube can be made relatively long. Furthermore, the plurality of ribs further have the first layer and the second layer in order, and the average hole diameter of the plurality of pores in the second layer is larger than the average hole diameter of the plurality of pores in the first layer, so that the phase change of the processing fluid can be easily caused by the small holes in the first layer, and the large holes in the second layer are used as gas-liquid exchange passages, so that vaporized bubbles can leave the second layer even more quickly, and the processing fluid can enter the space of the first layer quickly, thereby increasing the efficiency of heat exchange.

[0037] Although the present invention has already been presented using comparable examples described above, it is not limited to the present invention. As long as any person familiar with this art does not deviate from the spirit and scope of the invention, any changes or modifications made in accordance with the above-described examples will still fall within the scope of the art protected by the present invention. Therefore, the scope of protection of the present invention should naturally include changes within the meaning and equivalent scope described in the claims of the appended patent. Furthermore, if combinations of the above-described examples are possible, the present invention includes embodiments in any combination thereof. [Explanation of Symbols]

[0038] 1. Body 11 Ribs 12 Side wall 13 recess 2 porous layer 21 First layer 22 Second layer S Space W1 First thickness W2 Second thickness W3 Maximum Interval H1 First projection height H2 Second projection height H3 Radial thickness D1 First mean thickness D2 Second mean thickness

Claims

1. It includes a tubular body and a porous layer, The tube has a plurality of ribs, which extend along the axial direction of the tube and are formed on the inner circumferential wall of the tube. A heat exchange tube characterized in that the porous layer has a plurality of pores, the porous layer is located on at least the plurality of ribs, the porous layer has a first layer and a second layer, the first layer covers the plurality of ribs, the second layer is located on the surface of the first layer, and the average pore diameter of the plurality of pores in the second layer is larger than the average pore diameter of the plurality of pores in the first layer.

2. The heat exchange tube according to claim 1, characterized in that the material of the tube body contains 75 to 95% by weight of copper and 5 to 25% by weight of nickel.

3. The heat exchange tube according to claim 1, characterized in that each of the ribs has opposing side walls, each of the ribs has a thickness between the side walls, two adjacent ribs each have a first thickness and a second thickness, and the ratio of the first thickness to the second thickness is 1:1 to 3.

4. The heat exchange tube according to claim 1, characterized in that each of the ribs has opposing side walls, each of the ribs has a thickness between the side walls, two adjacent ribs have a first thickness and a second thickness, there is a gap between two adjacent ribs, and the sum of the first thickness and the second thickness is twice the gap.

5. The heat exchange tube according to claim 1, characterized in that a recess is formed between two adjacent ribs, the two adjacent ribs have a first protrusion height and a second protrusion height with respect to the recess, and the ratio of the first protrusion height to the second protrusion height is 1:1 to 4.

6. The heat exchange tube according to claim 1, characterized in that a recess is formed between two adjacent ribs, the two adjacent ribs have a first protrusion height and a second protrusion height with respect to the recess, the recess has a radial thickness in the tube body, and the sum of the first protrusion height and the second protrusion height is three times the radial thickness.

7. The heat exchange tube according to claim 1, characterized in that the total thickness of the porous layer is 0.125 to 0.3 times the wall thickness of the tube.

8. The heat exchange tube according to claim 7, characterized in that the wall thickness of the tube body is 1 to 3 mm.

9. The heat exchange tube according to claim 1, characterized in that the first layer is formed by mixing a first metal powder with a binder and sintering, the second layer is formed by mixing a second metal powder with the binder and sintering, and the average particle size of the first metal powder is smaller than the average particle size of the second metal powder.

10. The heat exchange tube according to claim 9, characterized in that the binder is selected from the group consisting of polypropylene, polyethylene, polystyrene, polyethylene terephthalate, polymethacrylic acid, acetone, and xylene.

11. The heat exchange tube according to claim 9, characterized in that the first metal powder contains 75 to 95% by weight of copper and 5 to 25% by weight of nickel.

12. The heat exchange tube according to claim 9, characterized in that the second metal powder contains 75 to 95% by weight of copper and 5 to 25% by weight of nickel.

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