Vacuum heat exchange tube plate and heat exchanger thereof

Abstract

The utility model discloses a vacuum heat exchange tube plate and a heat exchanger thereof, belongs to the field of heat exchange, overcomes the defects that in the prior art, a vacuum heat exchanger used for flue gas heat exchange is prone to corrosion and leakage, and mainly provides the heat exchange tube plate. Comprising heat exchange plates used for exchanging heat with smoke and heat exchange pipes used for exchanging heat with fluid to be subjected to heat exchange, one heat exchange plate is correspondingly connected with at least one heat exchange pipe, each heat exchange plate is formed by welding two thin plates arranged front and back through a plurality of welding parts, and the unwelded parts of the heat exchange plates are away from each other to form a plurality of first flowing cavities. A phase change material is arranged in the first flowing cavity, a second flowing cavity is formed in the heat exchange pipe, and the second flowing cavity communicates with the first flowing cavity through a transition structure. The heat exchanger is mainly used for achieving the effects that the heat exchange element on the smoke side is not prone to corrosion, and the heat exchange element on the fluid side to be subjected to heat exchange is not prone to leakage.

Description

Technical Field

[0001] This application relates to the field of heat exchange, and in particular to a vacuum heat exchange tube sheet and the heat exchanger thereof. Background Technology

[0002] A vacuum heat exchanger is a heat exchange device that operates in a vacuum environment, primarily used to transfer heat between fluids at different temperatures. Its structure typically includes a shell, tube bundle, and tube sheet. The shell ensures the internal vacuum environment, the tube bundle is the main site of heat exchange, and the tube sheet fixes the tube bundle and separates different fluid zones. Its working principle utilizes the special thermophysical properties of fluids under vacuum conditions, such as lower boiling points, allowing the low-temperature fluid to more easily evaporate and absorb heat in a vacuum environment. The high-temperature fluid then transfers heat to the low-temperature fluid through the tube bundle, achieving efficient heat transfer. Vacuum heat exchangers offer many advantages, such as achieving efficient evaporation at lower temperatures, reducing energy consumption, and effectively preventing material oxidation due to the vacuum environment, making them suitable for heating or cooling heat-sensitive materials. They are widely used in industries such as chemical, pharmaceutical, and food processing, and are crucial equipment for improving production efficiency and product quality.

[0003] However, existing vacuum heat exchangers use heat exchange tubes, which have low heat exchange efficiency. To improve heat exchange efficiency, spiral protrusions are formed on the sidewall of the heat exchange tube on the side with higher temperature to increase the contact area and improve heat exchange efficiency. However, when this type of heat exchanger exchanges heat with high-temperature flue gas, the flue gas often accumulates dust on the leeward side of the heat exchange tube on the spiral protrusions, which reduces the heat exchange efficiency on the leeward side. Furthermore, because the temperature changes greatly in the flue gas channel and it may contain water vapor, long-term use may even cause corrosion of the dust accumulation on the heat exchange tube, greatly reducing the life of the heat exchange tube.

[0004] When a single heat exchange plate is used to exchange heat with low-temperature fluid and flue gas, the welding quality of the welded rings is often unstable due to the large number of welded rings on the heat exchange plate. When the fluid on the low-temperature side is unstable, the welded rings on the low-temperature side may break and leak. At this time, the heat exchange plate will leak the low-temperature fluid into the flue during operation, causing a large amount of low-temperature fluid to rush into the flue gas passage, which will cause the entire heat exchanger to fail. Summary of the Invention

[0005] In order to overcome the shortcomings of existing vacuum heat exchangers used for flue gas heat exchange that are prone to corrosion and leakage, this application provides a vacuum heat exchange tube sheet, which achieves the effect that the heat exchange elements on the flue gas side are not prone to corrosion and the heat exchange elements on the fluid to be exchanged are not prone to leakage.

[0006] To achieve the above objectives, this application adopts the following technical solution: a vacuum heat exchange tube sheet, comprising a heat exchange plate for exchanging heat with flue gas and a heat exchange tube for exchanging heat with the fluid to be heat exchanged, wherein one heat exchange plate is connected to at least one heat exchange tube, the heat exchange plate is formed by welding two thin plates arranged one behind the other through several welding parts, the unwelded parts of the heat exchange plate are far apart to form several first flow cavities, the first flow cavities are provided with phase change material, the heat exchange tubes are provided with second flow cavities, and the second flow cavities are connected to the first flow cavities through a transition structure.

[0007] By adopting the above technical solution, this application has the following advantages: At the structural design level, using heat exchange tubes that do not require welding for heat exchange with the medium to be exchanged not only significantly improves the reliability of the equipment and reduces the risk of damage, but also effectively avoids the situation where the cryogenic fluid flows into the heat exchange tubes first and then enters the flue gas side. Simultaneously, using a heat exchange plate on the flue gas side reduces the leeward area and decreases ash accumulation, thereby ensuring stable heat exchange efficiency. In terms of the heat exchange method, the first flow chamber of the heat exchange plate is filled with a phase change material, which changes from a liquid to a gaseous state within it. The gaseous phase change material flows into the heat exchange tubes, transferring heat to the tubes and then transferring the temperature to the cryogenic fluid, achieving efficient heat exchange. After heat exchange is completed, the phase change material becomes liquid again and falls back into the heat exchange plate, thus indirectly transferring heat from the flue gas side to the fluid to be exchanged in this cycle. In addition, since the second flow chamber is isolated from the cryogenic fluid, even if the welding strength of the heat exchange plate is low and leakage occurs on the flue gas side, only the phase change material will leak out, thus preventing the cryogenic fluid from leaking to the flue gas side. Since the phase change material in the flow chamber is limited, if only the phase change material leaks, the impact on the flue gas side is small. However, the fluid to be exchanged is continuously flowing. If the fluid to be exchanged leaks to the flue gas side, it will cause corrosion of a large number of heat exchange elements, resulting in huge losses. Therefore, this design can minimize equipment losses and extend the service life of the equipment.

[0008] Furthermore, the first flow chamber is a plurality of vertically extending pipes spaced apart along the flue gas flow direction, and each first flow chamber is connected to a heat exchange tube.

[0009] By adopting the aforementioned technical solution, the vertically extending pipe shape provides a specific flow path for the phase change material, which is conducive to the circulation of the phase change material between liquid and gaseous states. It can also exchange heat with multiple independent first flow chambers in sequence, extending the contact path and time between the flue gas and the heat exchange plate. This facilitates the more complete transfer of heat from the flue gas to the phase change material, thereby improving the overall heat exchange efficiency.

[0010] Furthermore, the upper end of the transition structure is adapted to the part connected to the heat exchange tube, and the lower end of the transition structure is adapted to the part connected to the heat exchange plate.

[0011] Using the aforementioned technical solution, the upper end of the transition structure is adapted to the connection point with the heat exchange tube, allowing the upper end of the transition structure to be circular. This enables a good connection with the typically circular heat exchange tube, ensuring a tight and smooth connection. This allows the gaseous phase change material to smoothly enter the heat exchange tube from the transition structure, reducing flow resistance and facilitating heat transfer and phase change material circulation. The lower end of the transition structure is adapted to the connection point with the heat exchange plate, allowing the lower end of the transition structure to be elliptical. The connection point between the transition structure and the heat exchange plate is a elliptical pipe. Because the heat exchange plate is welded from two thin plates and has multiple first flow cavities, the elliptical pipe better matches the outlet shape of the first flow cavities, allowing the phase change material to enter the transition structure more smoothly from the first flow cavities, improving heat transfer efficiency and reducing heat loss at the connection point.

[0012] Furthermore, the shape of the heat exchange tube on the upper and lower projection planes is the same as the shape of the first flow cavity, and the transition structure is integrally formed with the heat exchange tube.

[0013] Using the aforementioned technical solution, the shape of the heat exchange tube on its upper and lower projection surfaces is identical to that of the first flow cavity. The transition structure is integrally formed with the heat exchange tube, allowing the transition structure to be manufactured together with the heat exchange tube and directly connected to the first flow cavity of the heat exchange plate after processing. This enables smoother flow of the phase change material from the transition structure into the heat exchange tube, reducing flow resistance and energy loss caused by abrupt shape changes. This shape design makes the connection between the heat exchange tube and the transition structure tighter and more natural, improving the stability of the entire heat exchange tube sheet structure. Due to the consistency of shape, the strength of the connection points can be better guaranteed under welding or other connection methods, reducing stress concentration problems caused by structural mismatch, lowering the risk of leakage or damage, and extending the service life of the equipment.

[0014] Furthermore, the first or second flow chamber is provided with a valve that connects or disconnects from the outside, and the valve can be connected to an air extraction device.

[0015] By employing the aforementioned technical solution, a valve is installed in the first or second flow chamber to connect or disconnect it from the outside environment. This valve can be used to connect a pressure-reducing extraction device, which can extract air from the chamber, thereby establishing a low-pressure environment within the chamber. For vacuum heat exchangers, the low-pressure environment allows the fluid to utilize its unique thermophysical properties (such as a lower boiling point) under low pressure, making it easier for the cryogenic fluid to evaporate and absorb heat, thus improving heat exchange efficiency.

[0016] Furthermore, the phase change material includes water, methanol, ethanol, and propane.

[0017] Using the aforementioned technical solution, substances such as water, methanol, ethanol, and propane all possess a certain latent heat of phase change, which can absorb or release a large amount of heat during phase change (from liquid to gas or from gas to liquid). For example, water absorbs a large amount of heat when it evaporates. Through this phase change process, heat can be effectively absorbed from the flue gas and released on the heat exchanger tube side, transferring the heat to the fluid to be exchanged, thus improving heat exchange efficiency and making heat transfer more complete and efficient.

[0018] A heat exchanger includes an upper heat exchange chamber for flowing a fluid to be heat exchanged, a lower heat exchange chamber for flowing high-temperature flue gas, and the aforementioned heat exchange tube sheet. The upper and lower heat exchange chambers are isolated from each other. The heat exchange tubes in the heat exchange tube sheet are located in the upper heat exchange chamber, and the heat exchange plates are located in the lower heat exchange chamber.

[0019] By adopting the aforementioned technical solution, heat exchange tubes are placed in the upper heat exchange chamber for the flow of the fluid to be heat exchanged, and heat exchange plates are placed in the lower heat exchange chamber for the flow of high-temperature flue gas, forming distinct upper and lower heat exchange zones. When the high-temperature flue gas flows through the heat exchange plates, heat can be rapidly transferred to the phase change material inside the heat exchange plates. The phase change material then transfers the heat to the fluid to be heat exchanged in the heat exchange tubes through a transition structure, achieving efficient heat transfer from top to bottom. This fully utilizes the heat exchange characteristics of different components and improves the overall heat exchange efficiency.

[0020] Furthermore, the water inlet of the upper heat exchange chamber is located downstream of the flue gas flow direction, and the water outlet of the upper heat exchange chamber is located upstream of the flue gas flow direction.

[0021] Using the aforementioned technical solution, the inlet of the upper heat exchange chamber is located downstream of the flue gas flow direction, and the outlet is located upstream of the flue gas flow direction, forming a reverse heat exchange method. In reverse heat exchange, after the fluid to be heat exchanged (low-temperature fluid) enters the upper heat exchange chamber, it first comes into contact with the relatively low-temperature heat exchange tube section (because after the previous heat exchange, the heat absorbed by this part of the heat exchange tube from the flue gas has been transferred to the fluid). As the fluid flows in the heat exchange chamber, it gradually flows towards the higher-temperature heat exchange tube section. At this time, the fluid's own temperature is also constantly rising. This ensures that the fluid maintains a large temperature difference with the heat exchange tube throughout the entire heat exchange process, thereby increasing the driving force of heat transfer, enhancing the heat exchange effect, and effectively improving the overall heat exchange efficiency of the heat exchanger.

[0022] Furthermore, the upper heat exchange cavity is provided with several staggered baffles to extend the flow path of the fluid in the upper heat exchange cavity.

[0023] By employing the aforementioned technical solution, the staggered distribution of the baffles effectively extends the flow path of the fluid to be heat-exchanged within the upper heat exchange chamber. The fluid needs to flow along the tortuous channels formed by the baffles, increasing its residence time within the heat exchange chamber. This allows the fluid more time to exchange heat with the heat exchange tubes, enabling more efficient heat transfer from the tubes to the fluid, thereby significantly improving heat exchange efficiency and ensuring effective heat utilization.

[0024] Furthermore, the angle between the heat exchange tube sheet and the horizontal plane is greater than 30°.

[0025] Using the aforementioned technical solution, when the angle between the heat exchanger tube sheet and the horizontal plane is greater than 30°, it facilitates the circulation of the phase change material (PCM) between the gaseous and liquid states within the first flow chamber of the heat exchanger plate. The gaseous PCM rises into the heat exchanger tubes upon heating, releases heat within the tubes, and then returns to a liquid state. Due to the tilt angle, the liquid PCM can more smoothly flow back into the first flow chamber of the heat exchanger plate under gravity, ensuring continuous circulation of the PCM and maintaining a stable heat exchange effect. If the angle is too small, the backflow of the liquid PCM may be hindered, affecting circulation efficiency and thus reducing heat exchange efficiency. Attached Figure Description

[0026] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0027] Figure 1 This is a schematic diagram of a vacuum heat exchanger tube sheet according to this application;

[0028] Figure 2 This is a schematic diagram of a heat exchanger;

[0029] Figure 3 for Figure 2 The right view;

[0030] Figure 4 for Figure 3 A sectional view along the AA direction.

[0031] Figure descriptions: 1. Heat exchange plate; 11. First flow chamber; 2. Heat exchange tube; 21. Second flow chamber; 3. Transition structure; 4. Valve; 5. Upper heat exchange chamber; 51. Inlet; 52. Outlet; 53. Baffle; 6. Lower heat exchange chamber. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0033] The terms "first," "second," etc. (if present) in the specification and claims of this application are used to distinguish similar objects, not to describe a specific order or sequence. Even if "second" is used before a technical feature for distinction, it does not necessarily imply the presence of "first." It should be understood that in this application, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. It should be understood that in this application, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, X and / or Y can represent: X alone, X and Y simultaneously, and Y alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Containing X, Y, and Z," "Containing X, Y, and Z" means that all three X, Y, and Z are included; "Containing X, Y, or Z" means that one of X, Y, and Z is included; "Containing X, Y, and / or Z" means that any one, two, or three of X, Y, and Z are included.

[0034] The technical solutions of this application will be described in detail below with specific embodiments. The following specific embodiments can be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0035] like Figures 1 to 4 As shown, this application provides a vacuum heat exchanger tube sheet, including a heat exchange plate 1 for exchanging heat with flue gas and a heat exchange tube 2 for exchanging heat with the fluid to be heat exchanged. Each heat exchange plate 1 is connected to at least one heat exchange tube 2. The heat exchange plate 1 is formed by welding two thin plates arranged one behind the other through several welding parts. The unwelded parts of the heat exchange plate 1 are far apart from each other to form several first flow cavities 11. The first flow cavities 11 are provided with phase change material. The heat exchange tube 2 is provided with a second flow cavity 21. The second flow cavity 21 is connected to the first flow cavity 11 through a transition structure 3.

[0036] By adopting the above technical solution, this application has the following advantages: At the structural design level, using the heat exchange tube 2, which requires no welding, for heat exchange with the medium to be exchanged not only significantly improves the reliability of the equipment and reduces the risk of damage, but also effectively avoids the situation where the low-temperature fluid first flows into the heat exchange tube 2 and then enters the flue gas side. Simultaneously, using the heat exchange plate 1 on the flue gas side reduces the leeward area and the degree of ash accumulation, thereby ensuring stable heat exchange efficiency. In terms of the heat exchange method, the first flow cavity 11 of the heat exchange plate 1 is filled with a phase change material, which changes from liquid to gas within it. The gaseous phase change material flows into the heat exchange tube 2, transferring heat to the heat exchange tube 2, and then transferring the temperature to the low-temperature fluid, achieving efficient heat exchange. After heat exchange is completed, the phase change material becomes liquid again and falls back into the heat exchange plate 1, thus indirectly transferring heat from the flue gas side to the fluid to be exchanged in this cycle. In addition, since the second flow chamber 21 is isolated from the cryogenic fluid, even if the welding strength of the heat exchange plate 1 is low and leakage occurs on the flue gas side, only the phase change material will leak out, thus preventing the cryogenic fluid from leaking to the flue gas side. Since the phase change material in the flow chamber is limited, if only the phase change material leaks, the impact on the flue gas side will be small. However, the fluid to be exchanged is flowing continuously. If the fluid to be exchanged leaks to the flue gas side, it will cause corrosion of a large number of heat exchange elements, resulting in huge losses. Therefore, this design can minimize equipment losses and extend the service life of the equipment.

[0037] Understandably, in other embodiments, the first flow chambers 11 in the same heat exchange plate 1 are interconnected so that all air inside the same heat exchange plate can be extracted through only one interface to achieve the effect of reducing air pressure.

[0038] Understandably, in other embodiments, the second flow chambers 21 in the heat exchange tubes 2 on the same heat exchange plate 1 are interconnected, so that all the air inside the same heat exchange plate can be extracted through only one interface to achieve the effect of reducing air pressure.

[0039] Understandably, in other embodiments, the first flow chambers 11 in the same heat exchange plate 1 are interconnected, and the second flow chambers 21 connected to the first flow chambers 11 in the same heat exchange plate 1 are also interconnected, so that all the air inside the same heat exchange plate can be extracted through only one interface to achieve the effect of reducing air pressure.

[0040] Furthermore, the first flow chamber 11 consists of multiple vertically extending pipes spaced apart along the flue gas flow direction, and each first flow chamber 11 is connected to a heat exchange tube 2.

[0041] By adopting the aforementioned technical solution, the vertically extending pipe shape provides a specific flow path for the phase change material, which is conducive to the circulation of the phase change material between the liquid and gas states. It can also exchange heat with multiple independent first flow chambers 11 in sequence, extending the contact path and time between the flue gas and the heat exchange plate 1. This facilitates the more complete transfer of heat from the flue gas to the phase change material, thereby improving the overall heat exchange efficiency.

[0042] Furthermore, the upper end of the transition structure 3 is adapted to the part connected to the heat exchange tube 2, and the lower end of the transition structure 3 is adapted to the part connected to the heat exchange plate 1.

[0043] Using the aforementioned technical solution, the upper end of the transition structure 3 is adapted to the connection point with the heat exchange tube 2, allowing the upper end of the transition structure 3 to be circular. This enables a good connection with the typically circular heat exchange tube 2, ensuring a tight and smooth connection. This allows the gaseous phase change material to smoothly enter the heat exchange tube 2 from the transition structure 3, reducing flow resistance and facilitating heat transfer and the circulation of the phase change material. The lower end of the transition structure 3 is adapted to the connection point with the heat exchange plate 1, allowing the lower end of the transition structure 3 to be made into a near-elliptical pipe. Because the heat exchange plate 1 is welded from two thin plates and has multiple first flow cavities 11 inside, the near-elliptical pipe can better fit the outlet shape of the first flow cavities 11, making it easier for the phase change material to enter the transition structure 3 from the first flow cavities 11. This improves the efficiency of heat transfer and reduces heat loss at the connection point.

[0044] Furthermore, the shape of the heat exchange tube 2 on the upper and lower projection planes is the same as the shape of the first flow cavity 11, and the transition structure 3 is integrally formed with the heat exchange tube 2.

[0045] Using the aforementioned technical solution, the shape of the heat exchange tube 2 on its upper and lower projection surfaces is the same as that of the first flow cavity 11, and the transition structure 3 is integrally formed with the heat exchange tube 2. This allows the transition structure 3 to be manufactured together with the heat exchange tube 2, and after manufacturing, it can be directly connected to the first flow cavity 11 of the heat exchange plate 1. This enables the phase change material to flow more smoothly from the transition structure 3 into the heat exchange tube 2, reducing flow resistance and energy loss caused by abrupt shape changes. This shape design makes the connection between the heat exchange tube 2 and the transition structure 3 tighter and more natural, improving the stability of the entire heat exchange tube plate structure. Due to the consistency of shape, the strength of the connection parts can be better guaranteed under welding or other connection methods, reducing stress concentration problems caused by structural mismatch, lowering the risk of leakage or damage, and extending the service life of the equipment.

[0046] Furthermore, the first flow chamber 11 or the second flow chamber 21 is provided with a valve that connects or disconnects from the outside, and the valve 4 can be connected to an air extraction device.

[0047] Using the aforementioned technical solution, a valve 4 is provided in the first flow chamber 11 or the second flow chamber 21 to connect or disconnect from the outside. The valve 4 can be used to connect to a pressure-reducing evacuation device, which can extract air from the chamber, thereby establishing a low-pressure environment within the chamber. For vacuum heat exchangers, the low-pressure environment utilizes the special thermophysical properties of fluids at low pressure (such as a lower boiling point), making it easier for the cryogenic fluid to evaporate and absorb heat, thus improving heat exchange efficiency. Understandably, when evacuation is needed, the valve 4 is connected to the evacuation device for evacuation, and when evacuation is not needed, the valve 4 is disconnected from the evacuation device.

[0048] Furthermore, the phase change material includes water, methanol, ethanol, and propane.

[0049] Using the aforementioned technical solution, substances such as water, methanol, ethanol, and propane all possess a certain latent heat of phase change, which can absorb or release a large amount of heat during phase change (from liquid to gas or from gas to liquid). For example, water absorbs a large amount of heat when it evaporates. Through this phase change process, heat can be effectively absorbed from the flue gas and released on both sides of the heat exchange tube, transferring it to the fluid to be exchanged, thus improving heat exchange efficiency and making heat transfer more complete and efficient.

[0050] A heat exchanger includes an upper heat exchange chamber 5 for flowing a fluid to be heat exchanged, a lower heat exchange chamber 6 for flowing high-temperature flue gas, and the aforementioned heat exchange tube sheet. The upper heat exchange chamber 5 and the lower heat exchange chamber 6 are isolated from each other. The main body of the heat exchange tube 2 in the heat exchange tube sheet is located in the upper heat exchange chamber 5, and the heat exchange plate 1 is located in the lower heat exchange chamber 6.

[0051] By adopting the aforementioned technical solution, heat exchange tube 2 is placed in the upper heat exchange chamber 5 for the flow of the fluid to be heat exchanged, and heat exchange plate 1 is placed in the lower heat exchange chamber 6 for the flow of high-temperature flue gas, forming a distinct upper and lower heat exchange zone. When the high-temperature flue gas flows through the heat exchange plate 1, the heat can be rapidly transferred to the phase change material inside the heat exchange plate 1. The phase change material then transfers the heat to the fluid to be heat exchanged in the heat exchange tube 2 through the transition structure 3, realizing efficient heat transfer from top to bottom, making full use of the heat exchange characteristics of different components, and improving the overall heat exchange efficiency.

[0052] Specifically, the channel between the two adjacent heat exchange plates 1 is used to circulate high-temperature flue gas.

[0053] Furthermore, the water inlet 51 of the upper heat exchange chamber 5 is located downstream in the flue gas flow direction, and the water outlet 52 of the upper heat exchange chamber 5 is located upstream in the flue gas flow direction.

[0054] Using the aforementioned technical solution, the inlet 51 of the upper heat exchange chamber 5 is located downstream of the flue gas flow direction, and the outlet 52 is located upstream of the flue gas flow direction, forming a reverse heat exchange method. In reverse heat exchange, after the heat exchange fluid (low-temperature fluid) enters the upper heat exchange chamber 5, it first comes into contact with the relatively low-temperature part of the heat exchange tube 2 (because after the previous heat exchange, the heat absorbed by this part of the heat exchange tube 2 from the flue gas has been transferred to the fluid). As the fluid flows in the heat exchange chamber, it gradually flows towards the higher-temperature part of the heat exchange tube 2. At this time, the temperature of the fluid itself is also constantly rising. This ensures that the fluid maintains a large temperature difference with the heat exchange tube 2 throughout the entire heat exchange process, thereby increasing the driving force of heat transfer, enhancing the heat exchange effect, and effectively improving the overall heat exchange efficiency of the heat exchanger.

[0055] Furthermore, the upper heat exchange cavity 5 is provided with several staggered baffles 53 to extend the flow path of the fluid in the upper heat exchange cavity 5.

[0056] By employing the aforementioned technical solution, the staggered distribution of the baffles 53 effectively extends the flow path of the fluid to be heat-exchanged within the upper heat exchange chamber 5. The fluid needs to flow along the tortuous channels formed by the baffles 53, increasing the residence time of the fluid within the heat exchange chamber. This allows the fluid more time to exchange heat with the heat exchange tubes 2, enabling more efficient heat transfer from the heat exchange tubes 2 to the fluid, thereby significantly improving heat exchange efficiency and ensuring effective heat utilization.

[0057] Furthermore, the angle between the heat exchange tube sheet and the horizontal plane is greater than 30°.

[0058] Using the aforementioned technical solution, when the angle between the heat exchanger tube sheet and the horizontal plane is greater than 30°, it facilitates the circulation of the phase change material (PCM) between the gaseous and liquid states within the first flow chamber 11 of the heat exchanger plate 1. The gaseous PCM rises into the heat exchanger tube 2 upon heating, releases heat within the tube 2, and then returns to a liquid state. Due to the tilt angle, the liquid PCM can more smoothly flow back into the first flow chamber 11 of the heat exchanger plate 1 under gravity, ensuring continuous circulation of the PCM and maintaining a stable heat exchange effect. If the angle is too small, the return flow of the liquid PCM may be hindered, affecting the circulation efficiency and thus reducing the heat exchange efficiency.

[0059] Furthermore, the heat exchange plate 1 includes the welded portion and the connecting portion, the welded portion separating the two sides of the first flow chamber 11, and the connecting portion connecting two adjacent first flow chambers 11.

[0060] Furthermore, the connecting portion is located above the liquid surface of the liquid phase change material.

[0061] By adopting the aforementioned technical solution, since the location of the connecting section increases the risk of leakage compared to the original structure, placing the connecting section above the liquid surface reduces the risk of liquid phase change material leaking into other chambers. Even if leakage occurs, the gaseous accompanying material will leak first, and the losses caused by the gaseous phase change material entering the flue gas channel are far less than the impact of the liquid phase change material. Furthermore, pressure balance within the system is crucial during the flow and heat transfer of the gaseous phase change material. Having the connecting section above the liquid surface facilitates pressure balance between adjacent chambers. The gaseous phase change material can quickly flow from a higher-pressure chamber to a lower-pressure chamber through the connecting section, resulting in a more uniform pressure distribution throughout the system and avoiding problems such as poor flow of the phase change material or system instability caused by pressure imbalances.

[0062] In addition to the preferred embodiments described above, this application has other implementation methods. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection claimed in this application.

Claims

1. A vacuum heat exchanger tube sheet, characterized in that, It includes a heat exchange plate for exchanging heat with flue gas and a heat exchange tube for exchanging heat with the fluid to be heated. Each heat exchange plate is connected to at least one heat exchange tube. The heat exchange plate is formed by welding two thin plates arranged one behind the other through several welding parts. The unwelded parts of the heat exchange plate are far apart to form several first flow cavities. The first flow cavities are provided with phase change material. The heat exchange tube is provided with a second flow cavity. The second flow cavity is connected to the first flow cavity through a transition structure.

2. The vacuum heat exchanger tube sheet according to claim 1, characterized in that, The first flow chamber consists of multiple vertically extending pipes spaced apart along the flue gas flow direction, and each first flow chamber is connected to a heat exchange tube.

3. The vacuum heat exchanger tube sheet according to claim 1, characterized in that, The transition structure is an intermediate pipe, the upper end of which is adapted to the part connected to the heat exchange tube, and the lower end of which is adapted to the part connected to the heat exchange plate.

4. A vacuum heat exchanger tube sheet according to claim 1, characterized in that, The shape of the heat exchange tube on the upper and lower projection planes is the same as the shape of the first flow cavity, and the transition structure is integrally formed with the heat exchange tube.

5. A vacuum heat exchanger tube sheet according to claim 1, characterized in that, The first or second flow chamber is equipped with a valve that connects to or disconnects from the outside world, and the valve can be connected to an air extraction device.

6. A vacuum heat exchanger tube sheet according to claim 1, characterized in that, The phase change material includes water, methanol, ethanol, and propane.

7. A heat exchanger, characterized in that, It includes an upper heat exchange chamber for flowing the fluid to be heat exchanged, a lower heat exchange chamber for flowing high-temperature flue gas, and a heat exchange tube sheet as described in any one of claims 1 to 6, wherein the upper heat exchange chamber and the lower heat exchange chamber are isolated from each other, and the heat exchange tube body in the heat exchange tube sheet is located in the upper heat exchange chamber and the heat exchange plate is located in the lower heat exchange chamber.

8. A heat exchanger according to claim 7, characterized in that, The water inlet of the upper heat exchange chamber is located downstream of the flue gas flow direction, and the water outlet of the upper heat exchange chamber is located upstream of the flue gas flow direction.

9. A heat exchanger according to claim 7, characterized in that, The upper heat exchange cavity is provided with several staggered baffles to extend the flow path of the fluid in the upper heat exchange cavity.

10. A heat exchanger according to claim 7, characterized in that, The angle between the heat exchange tube sheet and the horizontal plane is greater than 30°.

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