A circular heat pipe horizontal shell and tube heat exchanger

Abstract

The present invention provides a circular heat pipe horizontal shell and tube heat exchanger, wherein a sealed vacuum space is formed between the upper chamber, the lower chamber, the steam pipe, and the condenser pipe, and the lower chamber is filled with liquid; the fluid in the shell side heats the heat exchange pipe, and after absorbing heat, the liquid evaporates along the steam pipe, enters the upper chamber, and then returns to the lower chamber along the condenser pipe; at least one of the steam pipe, the condenser pipe, and the upper chamber exchanges heat with a cold source in the heat exchange pipe. The present invention can rapidly evaporate the liquid in the chamber so that the steam fills the entire steam pipe and the condenser pipe, filling the entire heat exchange pipe, thereby widening the heat source distribution range and increasing the heat exchange area with the cold source. At the same time, the heating of the external pipe side and both rapidly heat the cold source in the heat exchange pipe, greatly improving the heat exchange efficiency of the heat exchanger.

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 essential equipment for heat exchange and transfer in chemical production processes. In fields such as petrochemicals, cryogenic refrigeration, air separation, and seawater desalination, it's often necessary to heat low-temperature fluids or cool high-temperature fluids, or to vaporize liquids into steam or condense steam into liquids. These processes are closely related to heat transfer and can therefore be accomplished using 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. Compared with various new plate heat exchangers, this traditional shell-and-tube heat exchanger has many disadvantages, such as low heat transfer efficiency and large heat exchanger size. However, shell-and-tube heat exchangers also have many advantages, 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. Currently, some high-efficiency heat exchangers have been developed in China based on smooth tubes, but the enhanced heat transfer effect is not ideal.

[0004] To date, traditional high-efficiency heat exchangers have mostly employed a single method to enhance heat transfer. One approach involves using roughened surface-enhanced heat exchange tubes. By modifying the wall surface design to create vortex-removing flows, these methods disrupt the boundary layer and improve heat transfer performance within it. Examples include transversely grooved tubes, spirally grooved tubes, longitudinally grooved tubes, corrugated tubes, positively swirling tubes, and finned tubes. Another approach involves using far-wall turbulence elements to generate continuous vortices, which, under the influence of centrifugal force, thoroughly mix the fluid at the tube center with the fluid in the wall boundary layer. However, this single method produces suboptimal heat transfer results.

[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 heat exchange tubes fixed to the tube sheet. A sealed heat exchange chamber is formed within the shell, and the heat exchange tubes are arranged within the heat exchange chamber. The tube sheet divides the heat exchange chamber into a first heat exchange chamber and a second heat exchange chamber. The heat exchange tubes are partially located within the first heat exchange chamber and partially located within the second heat exchange chamber. The first heat exchange chamber has a first fluid inlet and a first fluid outlet; the second heat exchange chamber has a second fluid inlet and a second fluid outlet. The heat exchange tubes are heat pipes. The present invention uses high-efficiency heat pipes to improve the structure of the shell and tube heat exchanger, so that the heat pipes, tube sheets, and the connection between the shell and tube sheets of the heat exchanger do not generate temperature difference stress, and can adapt to heat exchange between fluids with large temperature differences. Both sides adopt horizontal flushing, which has high heat exchange efficiency, simple structure, and convenient layout. The heat exchange tubes in the above-mentioned heat pipe heat exchanger are pure heat pipes, and fluid cannot flow through the heat exchange tubes, making it impossible to heat the fluid.

[0006] Therefore, in order to solve 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 structural heat exchanger to solve the above technical problems.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A circular heat pipe horizontal shell and tube heat exchanger, the heat exchanger includes a tube side and a shell side, the tube side includes a heat exchange tube, and the heat exchange tube includes 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 at the upper part of the tube body, 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.

[0010] As an improvement, the center line of the steam pipe passes through the center of the pipe body.

[0011] As an improvement, the condenser tube is an arc tube formed around the center of the tube body.

[0012] 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.

[0013] 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.

[0014] As an improvement, the diameter of the steam pipe is larger than that of the condenser pipe.

[0015] As an improvement, the diameter of the steam pipe is 2-3 times the diameter of the condenser pipe.

[0016] As an improvement, the steam pipe penetrates into the upper cavity to a certain height.

[0017] As an improvement, the length of the steam pipe extending into the upper cavity is 30-50% of the height of the upper cavity.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 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, filling 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, exchange 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 distribution range is wide and the heat exchange area with the cold source is large. At the same time, when the external tube side is heated, both quickly heat the cold source in the heat exchange tube, thereby greatly improving the heat exchange efficiency of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of the shell side of a shell and tube heat exchanger;

[0021] Figure 2 2. It is a schematic diagram of the cross-sectional structure of the heat exchange tube of the present invention;

[0022] Figure 3 1 is a schematic diagram of the cross-sectional structure of the improved heat exchange tube of the present invention;

[0023] Figure 4 This invention Figure 1 Schematic diagram of the axial cross-section of the heat exchange tube. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] A shell and tube heat exchanger, such as Figure 1As shown, the shell-and-tube heat exchanger includes a shell 1, heat exchange tubes 8, a tube-side inlet pipe 9, a tube-side outlet pipe 10, a shell-side inlet pipe 2, and a shell-side outlet pipe 3. A heat exchange tube bundle consisting of multiple 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 header 4, and the rear end of the rear tube sheet 7 is connected to a rear header 5. The tube-side outlet pipe 10 is disposed on the rear header 5; the tube-side inlet pipe 9 is disposed on the front header 4; the shell-side inlet pipe 2 and the shell-side outlet pipe 3 are both disposed on the shell 4. The tube-side fluid enters through the tube-side inlet pipe 9, exchanges heat with the shell-side fluid through the heat exchange tubes, and exits through the tube-side outlet pipe 10. As an improvement, the heat exchange tubes are microchannel heat exchange tubes.

[0026] 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 pipe 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 upper cavity 82 and the lower cavity 83 at the middle position, and the condenser pipe 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 pipe, and the lower cavity 83 is filled with liquid.

[0027] During heat exchange, the heat source in the shell side heats the heat exchange tubes 8, causing the liquid in the lower chamber of the heat exchange tubes to absorb heat and evaporate along the steam tubes, entering the upper chamber, and then returning to the lower chamber along the condenser tubes. The steam tubes, condenser tubes, and at least a portion of the upper chamber exchange heat with the fluid in the heat exchange tubes. Generally, the liquid or vapor-liquid mixture flowing downward in the condenser tubes is condensed after heat exchange.

[0028] 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, the liquid in the chamber can be evaporated quickly so that the steam fills the entire steam pipe and the condenser, filling the entire heat exchange tube. The heat source of the heat pipe is distributed throughout the heat exchange tube, so that the heat source distribution range is wide. The cold source in the heat exchange tube can quickly exchange heat with the steam inside, and at the same time exchange 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 distribution range is wide, and the heat exchange area with the cold source is large. At the same time, when the external tube side is heated, both quickly heat the cold source in the heat exchange tube at the same time, thereby greatly improving the heat exchange efficiency of the heat exchanger.

[0029] 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.

[0030] 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 be evaporated quickly, achieving a suction effect.

[0031] 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.

[0032] As an improvement, the diameter of the steam pipe is larger than that of the condenser, 2-3 times the diameter of the condenser. By setting the steam pipe diameter larger than 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 down the condenser, promoting fluid circulation.

[0033] As an improvement, Figure 3 As shown, the steam pipe is inserted into the upper chamber to a certain height, which is 30-50% of the upper chamber height. By rising to a certain height, it can ensure that all evaporation enters the upper chamber and prevent condensed liquid in the upper chamber from entering the steam pipe.

[0034] As an improvement, Figure 3 As shown, multiple rows of condenser tubes are arranged around the center of the tube body, with the diameter of the condenser tubes decreasing as they get closer to the center. By reducing the diameter of the condenser tubes closer to the center, flow resistance in the condenser tubes near the steam pipe is increased, preventing steam from entering the condenser tubes and enhancing fluid circulation. As steam becomes less likely to enter the condenser tubes as they get farther from the center, the tube diameters are increased, enhancing heat transfer while preventing steam from entering the condenser tubes.

[0035] 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.

[0036] As an improvement, Figure 4 As shown, the upper cavity and the lower cavity extend along the axial extension direction of the heat exchange tube.

[0037] 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 the cold source flowing in the heat exchange tube), for example Figure 4Multiple rows of steam pipes are shown in the figure. The diameters of the steam pipes and condensing pipes are getting larger and larger along the flow direction of the cold source. 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, the heat transfer area is increased, so that 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 enhancing heat transfer. In addition, by increasing the pipe diameter, the pressure decreases as the fluid flows, so that 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 is increased, further making the overall heat exchange uniform, achieving a heat exchange effect similar to countercurrent, and achieving the purpose of enhancing heat transfer.

[0038] Along the flow direction of the cold source, the diameters of the steam pipe and condenser pipe are continuously increased, which can further achieve a heat exchange effect similar to counter-flow and achieve the purpose of enhanced heat transfer.

[0039] As an improvement, multiple rows of steam tubes and condenser tubes are arranged along the axial direction of the heat exchange tubes (the direction of the cold source flow). Along the direction of the cold source flow, the distance between adjacent rows of steam tubes and the distance between adjacent rows of condenser tubes decrease. This enhances heat transfer at the rear end, as the temperature increases with the continuous flow of the cold source, and the heat transfer effect deteriorates. By increasing the distribution density and enlarging the heat transfer area, the overall heat transfer in the direction of the cold source flow is uniform, achieving a heat transfer effect similar to countercurrent flow, thereby achieving the purpose of enhanced heat transfer. Furthermore, by increasing the density, the pressure decreases as the fluid flows, allowing more steam to move in the direction of the fluid flow, which can also relieve front-end pressure and balance the overall pressure. Moreover, because the fluid distribution is increased, the heat transfer efficiency along the direction of the fluid flow increases, further uniformizing the overall heat transfer and achieving a heat transfer effect similar to countercurrent flow, thereby achieving the purpose of enhanced heat transfer.

[0040] Along the flow direction of the cold source, the distance between adjacent rows of steam pipes becomes smaller and larger, and the distance between adjacent rows of condenser pipes becomes smaller and larger, which can further achieve a heat exchange effect similar to countercurrent flow and achieve the purpose of enhanced heat transfer.

[0041] As an improvement, the heat exchanger is a horizontal shell and tube heat exchanger. As an improvement, a baffle 11 is provided 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 rate 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 rate in the middle is significantly greater than the heat exchange rate at the tube side inlet and outlet. Therefore, by changing the spacing between the baffles, the heat exchange area between the tube side fluid and the shell side fluid source in the baffle is also changed. Therefore, the uneven heat exchange rate is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0042] As an improvement, along the flow direction of the fluid within the tube, the spacing between the baffles increases in magnitude from the tube inlet to the middle of the tube. Then, from the middle of the tube to the tube outlet, the spacing between the baffles decreases in magnitude. This variation in magnitude makes the heat transfer per unit length of the entire fluid flow more uniform, further improving heat transfer efficiency.

[0043] Although the present invention has been disclosed above with reference to preferred embodiments, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection 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 provided in the tube body. The upper chamber is provided in the upper part of the tube body, and the lower chamber is provided 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 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, wherein The condenser is an arc tube formed around the center of the tube body.

4. The heat exchanger according to claim 1, wherein 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, wherein 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, wherein The steam pipe penetrates into the upper cavity to a certain height.

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