Circular heat pipe horizontal shell-and-tube heat exchanger

Abstract

The invention provides a circular heat pipe horizontal shell-and-tube heat exchanger which is characterized in that a sealed vacuumizing space is formed among an upper cavity, a lower cavity, a steam pipe and a condensation pipe, and the lower cavity is filled with liquid; the fluid in the shell pass heats the heat exchange tube, evaporates along the steam tube after absorbing heat, enters the upper cavity and then returns to the lower cavity along the condensation tube; at least one of the steam pipe, the condensation pipe and the upper cavity exchanges heat with a cold source in the heat exchange pipe. Liquid in the cavity can be evaporated quickly, so that steam fills the whole steam pipe and the condensation pipe and fills the whole heat exchange pipe, the distribution range of a heat source is wide, the heat exchange area with a cold source is large, meanwhile, the cold source in the heat exchange pipe is quickly heated by the heat source and the condensation pipe at the same time during heating of an external pipe pass, and the heat exchange efficiency of the heat exchanger is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of heat exchangers, and in particular relates to a circular heat pipe horizontal shell and tube heat exchanger. Background Art

[0002] Heat exchangers are indispensable equipment for heat exchange and transfer in chemical production. In the fields of petrochemicals, cryogenic refrigeration, air separation, seawater desalination, etc., it is often necessary to heat low-temperature fluids or cool high-temperature fluids, vaporize liquids into steam, or condense steam into liquids. These processes are closely related to heat transfer, and can therefore be completed through heat exchangers.

[0003] Commonly used heat exchangers include shell and tube heat exchangers and plate heat exchangers. Traditional shell and tube heat exchangers mostly use smooth tubes as heat exchanger tubes. This traditional shell and tube heat exchanger has many disadvantages compared with various new plate heat exchangers, such as low heat transfer efficiency and large heat exchanger volume; however, shell and tube heat exchangers also have many advantages of their own, such as simple manufacturing, high temperature and high pressure resistance, and easy maintenance. Therefore, it is urgent to develop a double-sided enhanced high-efficiency heat exchanger based on the traditional shell and tube heat exchanger. At present, some high-efficiency heat exchangers based on smooth tubes have appeared in China for secondary development, but they are not ideal in terms of enhanced heat transfer effect.

[0004] So far, traditional high-efficiency heat exchangers mostly use a single means of heat exchange enhancement. One is to use rough surface enhanced heat exchange tubes, and form vortex removal by improving the wall surface shape design to achieve the purpose of destroying the boundary layer and improving the heat transfer performance in the boundary layer, such as transverse groove tubes, spiral groove tubes, longitudinal groove tubes, corrugated tubes, positive rotation tubes and finned tubes. The second is to use far-wall spoiler elements to generate continuous vortices, so that the fluid in the center of the tube and the fluid in the wall boundary layer are fully mixed under the influence of centrifugal force. However, the heat exchange effect of a single means is not ideal.

[0005] Prior art CN102288055A discloses a heat pipe shell and tube heat exchanger, comprising a shell, a fluid inlet and a fluid outlet provided on the shell, a tube sheet, and a heat exchange tube fixed on the tube sheet. A closed heat exchange cavity is formed in the shell, and the heat exchange tube is arranged in the heat exchange cavity. The tube sheet divides the heat exchange cavity into a first heat exchange cavity and a second heat exchange cavity. The heat exchange tube is partially located in the first heat exchange cavity and partially located in the second heat exchange cavity. The first heat exchange cavity is provided with a first fluid inlet and a first fluid outlet; the second heat exchange cavity is provided with a second fluid inlet and a second fluid outlet, and the heat exchange tube is a heat pipe. The present invention adopts a high-efficiency heat pipe, improves the structure of the shell and tube heat exchanger, and makes the heat pipe, tube sheet, and the connecting part of the shell and tube sheet of the heat exchanger not generate temperature difference stress, and can adapt to heat exchange between fluids with large temperature difference; both sides adopt lateral flushing, and the heat exchange is efficient, the structure is simple, and the layout is convenient. The heat exchange tubes in the above-mentioned heat pipe heat exchanger adopt pure heat pipes, and the fluid cannot flow in the heat exchange tubes, so the fluid cannot be heated.

[0006] Therefore, in view of the above problems, the present invention provides a heat pipe heat exchanger with a new structure, which greatly improves the heat exchange effect. Summary of the invention

[0007] The present invention provides a new structure heat exchanger, thereby solving the above-mentioned technical problems.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows: A circular heat pipe horizontal shell and tube heat exchanger, the heat exchanger comprises a tube side and a shell side, the tube side comprises a heat exchange tube, the heat exchange tube comprises a circular tube body, characterized in that the fluid in the tube side is a cold source, the fluid in the shell side is a heat source, an upper chamber, a lower chamber, and a steam pipe and a condenser connecting the upper chamber and the lower chamber are arranged in the tube body, the upper chamber is arranged in the upper part of the tube body, the lower chamber is arranged in the lower part of the tube body, the steam pipe connects the middle position of the upper chamber and the lower chamber, and the condenser is arranged on both sides of the steam pipe; a closed vacuum space is formed between the upper chamber, the lower chamber, the steam pipe and the condenser, and the lower chamber is filled with liquid; the fluid in the shell side heats the heat exchange tube, and the liquid evaporates along the steam pipe after absorbing heat, enters the upper chamber, and then returns to the lower chamber along the condenser; at least one of the steam pipe, the condenser and the upper chamber exchanges heat with the cold source in the heat exchange tube.

[0009] As an improvement, the center line of the steam pipe passes through the center of the pipe body.

[0010] As an improvement, the condenser tube is an arc tube formed around the center of the tube body.

[0011] As an improvement, the upper cavity and the lower cavity are arc structures, wherein the upper cavity is an arc curved downward, and the lower cavity is an arc curved upward.

[0012] As an improvement, the line connecting the arc center lines of the upper cavity and the lower cavity passes through the center of the circle.

[0013] As an improvement, the diameter of the steam pipe is larger than that of the condenser pipe.

[0014] As an improvement, the diameter of the steam pipe is 2-3 times the diameter of the condenser pipe.

[0015] As an improvement, the steam pipe penetrates into the upper cavity to a certain height.

[0016] As an improvement, the length of the steam pipe penetrating into the upper cavity is 30-50% of the height of the upper cavity.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention improves the heat exchange tube structure of the heat exchanger. By setting the upper and lower chambers as well as the steam tube and the condenser tube, the liquid in the chamber can be evaporated quickly so that the steam fills the entire steam tube and the condenser tube, and fills the entire heat exchange tube. The cold source in the heat exchange tube can quickly exchange heat with the steam inside, and at the same time, it exchanges heat with the heat source in the shell side outside. The heat source is distributed throughout the heat exchange tube, so that the heat source is widely distributed and the heat exchange area with the cold source is large. At the same time, the external tube side is heated, and both quickly heat the cold source in the heat exchange tube at the same time, which greatly improves the heat exchange efficiency of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of the shell side of a shell and tube heat exchanger; Figure 2 is a schematic diagram of the cross-sectional structure of the heat exchange tube of the present invention; Figure 3 It is a schematic diagram of the cross-sectional structure of the improved heat exchange tube of the present invention; Figure 4 The present invention Figure 1 Schematic diagram of the axial cross-section of the heat exchange tube. DETAILED DESCRIPTION

[0019] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0020] A shell and tube heat exchanger, such as Figure 1As shown, the shell and tube heat exchanger includes a shell 1, a heat exchange tube 8, a tube-side inlet tube 9, a tube-side outlet tube 10, a shell-side inlet pipe 2 and a shell-side outlet pipe 3; a heat exchange tube bundle composed of a plurality of parallel heat exchange tubes 8 is connected to a front tube sheet 6 and a rear tube sheet 7; the front end of the front tube sheet 6 is connected to a front head 4, and the rear end of the rear tube sheet 7 is connected to a rear head 5; the tube-side outlet pipe 10 is arranged on the rear head 5; the tube-side inlet pipe 9 is arranged on the front head 4; the shell-side inlet pipe 2 and the shell-side outlet pipe 3 are both arranged on the shell 4; the tube-side fluid enters from the tube-side inlet pipe 9, exchanges heat with the shell-side fluid through the heat exchange tube, and exits from the tube-side outlet pipe 10. As an improvement, the heat exchange tube is a microchannel heat exchange tube.

[0021] Figure 2-3 A heat exchanger is shown, which includes a circular heat exchange tube. The heat exchange tube 8 includes a circular tube body 81, in which an upper cavity 82, a lower cavity 83, and a steam pipe 84 and a condenser 85 connecting the upper cavity and the lower cavity are arranged. The upper cavity 82 is arranged at the upper part of the tube body 81, and the lower cavity 83 is arranged at the lower part of the tube body. The steam pipe 84 connects the middle position of the upper cavity 82 and the lower cavity 83, and the condenser 85 is arranged on both sides of the steam pipe 84; a closed vacuum space is formed between the upper cavity, the lower cavity, the steam pipe and the condenser, and the lower cavity 83 is filled with liquid.

[0022] When the heat exchanger is exchanging heat, the heat source in the shell heats the heat exchange tube 8, so that the liquid in the lower chamber of the heat exchange tube absorbs heat and evaporates along the steam tube, enters the upper chamber, and then returns to the lower chamber along the condenser tube; the steam tube, the condenser tube and at least a part of the upper chamber exchange heat with the fluid in the heat exchange tube. In general, the downward flow in the condenser tube is the condensed liquid or vapor-liquid mixture after heat exchange.

[0023] The present invention improves the structure of the heat exchanger. By setting the upper and lower chambers as well as the steam pipe and the condenser pipe, the liquid in the chamber can be quickly evaporated so that the steam fills the entire steam pipe and the condenser pipe, and fills the entire heat exchange pipe. The heat source of the heat pipe is distributed throughout the heat exchange pipe, so that the heat source distribution range is wide. The cold source in the heat exchange pipe can quickly exchange heat with the steam inside, and at the same time, it exchanges heat with the heat source in the shell side outside. The heat source is distributed throughout the heat exchange pipe, so that the heat source distribution range is wide, and the heat exchange area with the cold source is large. At the same time, the external pipe side is heated, and both quickly heat the cold source in the heat exchange pipe at the same time, which greatly improves the heat exchange efficiency of the heat exchanger.

[0024] As an improvement, Figure 2 As shown, the center line of the steam pipe passes through the center of the pipe body. Figure 2As shown, the condenser tube is an arc tube formed around the center of the tube body. The above arrangement can make the overall heat evenly distributed in the heat exchange tube, making the overall heat exchange effect uniform and improving the heat exchange effect.

[0025] As an improvement, Figure 2 As shown, the upper chamber and the lower chamber are arc structures, wherein the upper chamber is an arc curved downward, and the lower chamber is an arc curved upward. By setting the arc shape, the liquid can evaporate quickly and achieve the effect of suction.

[0026] As an improvement, the line connecting the arc center lines of the upper cavity and the lower cavity passes through the center of the circle. The above arrangement can make the overall heat evenly distributed in the heat exchange tube, making the overall heat exchange effect uniform and improving the heat exchange effect.

[0027] As an improvement, the diameter of the steam pipe is larger than that of the condenser, which is 2-3 times the diameter of the condenser. By setting the diameter of the steam pipe larger than that of the condenser, the flow resistance of the steam pipe is smaller than that of the condenser, which can promote steam to flow from the steam pipe and flow down the condenser, thereby promoting the circulation of the fluid.

[0028] As an improvement, Figure 3 As shown, the steam pipe goes deep into the upper chamber to a certain height, which is 30-50% of the height of the upper chamber. By rising to a certain height, it can ensure that the evaporation enters the upper chamber and prevent the condensed liquid in the upper chamber from entering the steam pipe.

[0029] As an improvement, Figure 3 As shown, multiple rows of condensers are arranged around the center of the tube body, wherein the closer the distance to the center of the circle, the smaller the diameter of the condenser. By setting the condenser to have a smaller diameter as it is closer to the center of the circle, the flow resistance of the condenser close to the steam pipe can be increased to prevent steam from entering the condenser, thereby enhancing fluid circulation. As the distance from the center of the circle increases, it is less likely for steam to enter the condenser, so the diameter of the pipe is set larger to prevent steam from entering the condenser to achieve the purpose of enhancing heat transfer.

[0030] As an improvement, the closer the distance to the center of the circle, the smaller the diameter of the condenser tube becomes. The above arrangement can further prevent steam from entering the condenser tube and enhance heat transfer at the same time.

[0031] As an improvement, Figure 4 As shown, the upper chamber and the lower chamber extend along the axial extension direction of the heat exchange tube.

[0032] As an improvement, multiple rows of steam pipes and condenser pipes are arranged along the axial direction of the heat exchange tube (the direction of flow of the cold source in the heat exchange tube), for example Figure 4Multiple rows of steam pipes are shown in the figure. Along the flow direction of the cold source, the diameters of the steam pipes and condenser pipes are getting larger and larger. By setting the pipe diameter to gradually increase, the heat transfer is enhanced at the back, because as the cold source continues to flow, the temperature becomes higher and higher, and the heat exchange effect becomes worse and worse. By increasing the pipe diameter and increasing the heat transfer area, the overall heat exchange in the flow direction of the cold source is uniform, and a heat exchange effect similar to countercurrent is achieved, thereby achieving the purpose of enhanced heat transfer. In addition, by increasing the pipe diameter, as the fluid flow pressure decreases, more steam moves in the direction of fluid flow, which can also relieve the front end pressure and balance the overall pressure. Moreover, because the fluid distribution increases, the heat exchange efficiency along the fluid flow direction is increased, which further makes the overall heat exchange uniform, achieving a heat exchange effect similar to countercurrent, thereby achieving the purpose of enhanced heat transfer.

[0033] Along the flow direction of the cold source, the diameters of the steam pipe and the condenser pipe are increasing more and more, which can further achieve a counter-current heat exchange effect and achieve the purpose of enhanced heat transfer.

[0034] As an improvement, multiple rows of steam pipes and condenser tubes are arranged along the axial direction of the heat exchange tube (the flow direction of the cold source), wherein the distance between adjacent rows of steam pipes and the distance between adjacent rows of condenser tubes are getting smaller and smaller along the flow direction of the cold source. This strengthens the heat transfer at the back, because as the cold source continues to flow, the temperature becomes higher and higher, and the heat exchange effect becomes worse and worse. By increasing the distribution density and enlarging the heat transfer area, the overall heat exchange in the flow direction of the cold source is uniform, achieving a heat exchange effect similar to countercurrent, and achieving the purpose of strengthening heat transfer. In addition, by increasing the density, as the fluid flow pressure decreases, more steam moves in the direction of fluid flow, which can also relieve the front end pressure and balance the overall pressure. Moreover, because the fluid distribution increases, the heat exchange efficiency along the flow direction of the fluid increases, further making the overall heat exchange uniform, achieving a heat exchange effect similar to countercurrent, and achieving the purpose of strengthening heat transfer.

[0035] Along the flow direction of the cold source, the distance between adjacent rows of steam pipes is getting smaller and larger, and the distance between adjacent rows of condenser pipes is getting smaller and larger. This can further achieve a countercurrent-like heat exchange effect and achieve the purpose of enhanced heat transfer.

[0036] As an improvement, the heat exchanger is a horizontal shell and tube heat exchanger. As an improvement, a baffle 11 is arranged in the tube side of the heat exchanger. The shell side and the tube side are countercurrent flows, and along the flow direction of the fluid in the tube side, the spacing of the baffles increases continuously from the tube side inlet to the middle position of the tube side. Then from the middle position of the tube side to the tube side outlet, the spacing of the baffles decreases continuously. Because in the countercurrent process, the heat exchange of the shell side and the tube side per unit length along the flow process of the fluid is relatively uniform, so that the overall heat exchange effect is the best. However, it was found in experiments and simulations that the heat exchange of the middle part is significantly greater than the heat exchange of the tube side inlet and outlet. Therefore, by changing the spacing of the baffles, the heat exchange area of ​​the tube side fluid in the baffle and the shell side fluid source also changes. Therefore, the uneven heat exchange is compensated by the change of the area, so as to further improve the heat exchange efficiency.

[0037] As an improvement, along the flow direction of the fluid in the tube, from the tube entrance to the middle of the tube, the distance between the baffles increases continuously. Then, from the middle of the tube to the tube exit, the distance between the baffles decreases continuously. The above changes in the range can make the heat exchange per unit length of the entire fluid movement more uniform, further improving the heat exchange efficiency.

[0038] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A circular heat pipe horizontal shell and tube heat exchanger, the heat exchanger comprising a tube side and a shell side, the tube side comprising a heat exchange tube, the heat exchange tube comprising a circular tube body, characterized in that: The fluid in the tube side is a cold source, and the fluid in the shell side is a heat source. An upper chamber, a lower chamber, and a steam pipe and a condenser connecting the upper chamber and the lower chamber are arranged in the tube body. The upper chamber is arranged at the upper part of the tube body, and the lower chamber is arranged at the lower part of the tube body. The steam pipe connects the middle position of the upper chamber and the lower chamber, and the condenser is arranged on both sides of the steam pipe; a closed vacuum space is formed between the upper chamber, the lower chamber, the steam pipe and the condenser, and the lower chamber is filled with liquid; the fluid in the shell side heats the heat exchange tube, and the liquid absorbs heat and evaporates along the steam pipe, enters the upper chamber, and then returns to the lower chamber along the condenser; at least one of the steam pipe, the condenser and the upper chamber exchanges heat with the cold source in the heat exchange tube.

2. The heat exchanger according to claim 1, characterized in that The center line of the steam pipe passes through the center of the pipe body.

3. The heat exchanger according to claim 1, characterized in that The condenser tube is an arc tube formed around the center of the tube body.

4. The heat exchanger according to claim 1, characterized in that The upper cavity and the lower cavity are arc structures, wherein the upper cavity is an arc curved downward, and the lower cavity is an arc curved upward.

5. The heat exchanger according to claim 4, characterized in that The line connecting the arc center lines of the upper cavity and the lower cavity passes through the center of the circle.

6. The heat exchanger according to claim 1, characterized in that The diameter of the steam pipe is larger than that of the condenser pipe.

7. The heat exchanger according to claim 6, characterized in that The diameter of the steam pipe is 2-3 times the diameter of the condenser pipe.

8. The heat exchanger according to claim 1, characterized in that The steam pipe penetrates into the upper cavity to a certain height.

9. The heat exchanger according to claim 8, characterized in that The length of the steam pipe penetrating into the upper cavity is 30-50% of the height of the upper cavity.

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