Axial tube plate module combined heat exchanger and working method

Abstract

The invention relates to the technical field of heat exchangers, in particular to an axial tube plate module combined heat exchanger and a working method.The heat exchanger comprises two end sockets, a plurality of axial tube plate modules sequentially arranged in series, a first medium inlet, a first medium outlet, a second medium inlet and a second medium outlet, the axial tube plate module comprises a shell, two vertical tube plates arranged in parallel in the axial direction of the shell and a plurality of first heat exchange tubes penetrating through the vertical tube plates, the shell is divided into a middle shell pass cavity and two side tube pass cavities through the two vertical tube plates, partition plates are arranged at the ends of the tube pass cavities, and communicating holes are formed in part of the partition plates, so that shell pass flow channels are sequentially communicated in the multiple modules. Forming a serpentine flow path of the first medium; the shell pass cavities of the adjacent modules communicate with each other to form a second medium flow channel, each axial tube plate module is equivalent to an independent heat exchange unit, multi-stage heat exchange is achieved in a single device through a modular structure, multiple devices and external pipelines are not needed, the heat exchange efficiency is remarkably improved, and the structure is simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchangers, in particular to an axial tube plate module combined heat exchanger and working method. BACKGROUND

[0002] A heat exchanger is a device that utilizes the heat exchange between two different temperature media, widely used in chemical, metallurgical, energy, refrigeration and environmental engineering industries, and its basic principle is to make cold and hot media flow in the tube and shell passages respectively through the interwall structure with heat transfer function, so as to realize energy transfer; in practical application, in order to obtain higher heat efficiency, multiple BXM heat exchangers are often used in series to form a multi-stage cross-flow heat exchange system.

[0003] Although the series connection of multiple devices improves the overall heat transfer effect to some extent, it also introduces many engineering problems, first, the series connection of multiple devices increases the number of medium channels and the system flow resistance, which needs to be compensated by increasing the number of devices or improving the flow rate, thereby increasing energy consumption; second, the medium flow path in the series connection structure is complex, the flow field distribution is uneven, and leakage and bias flow phenomena are easy to occur, which weakens the effective heat transfer area and reduces the heat exchange performance; in addition, the centralized opening and connection structure of multiple devices will cause local stress concentration and processing deformation risk, and under the action of cyclic load, fatigue damage is easy to occur, affecting the overall structural reliability; due to the connection of the shell passage through the external header and multiple pipes, the leakage risk points of the system increase, and the assembly and maintenance difficulty increases.

[0004] The information disclosed in this BACKGROUND section is only intended to enhance the understanding of the general background of the application, and should not be considered as recognition or implicit acknowledgement in any form that this information constitutes prior art known to those skilled in the art. SUMMARY

[0005] The axial tube plate module combined heat exchanger and working method provided in the present application effectively solve the problems pointed out in the background.

[0006] In order to achieve the above purpose, the technical solution adopted by the present application is: An axial tube plate module combined heat exchanger, comprising: two end heads, a plurality of axial tube plate modules arranged in series between the two end heads, a first medium inlet and a first medium outlet located at the two end axial tube plate modules, and a second medium inlet and a second medium outlet arranged on the two end heads respectively; The axial tube plate module comprises a shell, at least two vertical tube plates arranged axially and parallel in the shell, and a plurality of first heat exchange tubes penetrating through the two vertical tube plates; Two vertical tube plates divide the shell into a middle shell-side cavity and two tube-side cavities on both sides of the shell-side cavity; The inner cavity of the first heat exchange tube constitutes part of a tube-side flow channel, and the end of the tube-side cavity is provided with a partition plate, part of which is provided with a communication hole. The tube-side flow channel is sequentially communicated in series in multiple axial tube plate modules through the partition plates with and without the communication hole, forming an approximate serpentine path for the circulation of the first medium. The adjacent two axial tube plate modules are communicated through their adjacent shell-side cavities, and together constitute a shell-side flow channel for the circulation of the second medium.

[0007] Further, the second heat exchange tube arranged in a serpentine rotation manner is arranged in the edge space between the first heat exchange tube and the shell, the second heat exchange tube penetrates through multiple axial tube plate modules, and the inlet and outlet of the second heat exchange tube are respectively connected with the shell-side cavities of the axial tube plate modules at both ends, so that the first medium circulates in the second heat exchange tube.

[0008] Further, the serpentine rotation part of the second heat exchange tube is formed in the same axial tube plate module, or the serpentine rotation part of the second heat exchange tube is formed between adjacent axial tube plate modules.

[0009] Further, the first heat exchange tube is a straight tube.

[0010] Further, the first heat exchange tube is a serpentine tube, and the serpentine rotation plane of the serpentine tube is arranged perpendicular to the axis of the shell, or the serpentine rotation plane of the serpentine tube is arranged parallel to the axis of the shell.

[0011] Further, the first heat exchange tube is arranged in staggered layers between adjacent layers.

[0012] Further, the axial tube plate module is provided with two groups of vertical tube plates perpendicular to each other, the first heat exchange tube is arranged between the two groups of vertical tube plates, forming two tube-side flow channels and one shell-side flow channel, and the two tube-side flow channels are independent of each other or connected in series.

[0013] Further, the vertical tube plate is provided with a buffer structure at the connection between the inner side of the shell and the vertical tube plate.

[0014] Further, the buffer structure is an inclined section or a circular arc section arranged along the connecting edge of the vertical tube plate and the inner wall of the shell, and the inclined section or the circular arc section is arranged obliquely in an eight-shaped distribution.

[0015] The application also includes a working method of an axial tube plate module combined heat exchanger, comprising: The first medium is introduced from the first medium inlet, so that the first medium flows sequentially along the tube flow channels in the plurality of axial tube sheet modules, and forms an approximately serpentine flow path through the baffle with connecting holes. The second medium is introduced from the second medium inlet and flows crosswise with the first medium along the shell-side flow channel to exchange heat. After heat exchange, the first medium and the second medium are discharged from their respective first medium outlet and second medium outlets, respectively. The positions of the first medium inlet and the first medium outlet are interchanged as needed; correspondingly, the positions of the second medium inlet and the second medium outlet are interchanged as needed, thereby achieving overall parallel or counter-current heat exchange.

[0016] The technical solution of this invention can achieve the following technical effects: Each axial tube sheet module in this invention is equivalent to an independent BXM heat exchanger in a traditional system. Through modular structure, multi-stage heat exchange is achieved within the same device, enabling the heat exchange process that previously required multiple devices and complex external piping to be completed in a single device. Since each axial tube sheet module has an independent tube-side cavity and shell-side cavity, and the modules are connected by partition holes to form a continuous serpentine flow channel, the first medium can flow back and forth sequentially within the module, simplifying the heat exchanger structure while improving heat exchange efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an axial tube sheet modular heat exchanger. Figure 2 This is a cross-sectional view of an axial tube sheet modular heat exchanger. Figure 3 This is a schematic diagram of the structure of the second heat exchange tube in the heat exchanger. Figure 4 This is a schematic diagram of the first specific embodiment of the first heat exchange tube; Figure 5 This is a schematic diagram of a second specific implementation of the first heat exchange tube; Figure 6 This is a structural schematic diagram of a third specific embodiment of the first heat exchange tube; Figure 7This is a schematic diagram of a specific implementation method in which adjacent layers of the first heat exchange tube are arranged in a staggered manner. Figure 8 This is a schematic diagram of the buffer structure; Figure 9 This is a schematic diagram of the transition angle.

[0019] Reference numerals: 1. Head; 2. Axial tube sheet module; 21. Shell; 22. Vertical tube sheet; 221. Buffer structure; 23. First heat exchange tube; 24. Baffle; 241. Connecting hole; 241a. Transition angle; 25. Tube-side cavity; 26. Shell-side cavity; 27. Edge space; 28. Second heat exchange tube; 281. Serpentine rotating section; 3. First medium inlet; 4. First medium outlet; 5. Second medium inlet; 6. Second medium outlet; 01, First medium; 02, Second medium. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] like Figures 1 to 9 As shown: An axial tube sheet module combined heat exchanger includes: end caps 1 at both ends, a plurality of axial tube sheet modules 2 arranged in series between the two end caps 1, a first medium inlet 3 and a first medium outlet 4 located at the two end axial tube sheet modules 2, and a second medium inlet 5 and a second medium outlet 6 respectively arranged on the two end caps 1. The axial tube sheet module 2 includes a housing 21, at least two vertical tube sheets 22 disposed inside the housing 21 and arranged parallel to the axial direction of the housing 21, and a plurality of first heat exchange tubes 23 penetrating the two vertical tube sheets 22. The two vertical tube plates 22 divide the interior of the shell 21 into the shell-side cavity 26 in the middle, and the two tube-side cavities 25 located on both sides of the shell-side cavity 26. The inner cavity of the first heat exchange tube 23 forms part of the tube-side flow channel. A baffle 24 is provided at the end of the tube-side cavity 25. A connecting hole 241 is provided on part of the baffle 24. Through the baffles 24 with and without connecting holes 241, the tube-side flow channel is connected sequentially in multiple axial tube sheet modules 2 connected in series to form an approximately serpentine path for the flow of the first medium 01. Two adjacent axial tube sheet modules 2 are connected through their adjacent shell-side cavities 26, together forming a shell-side flow channel for the flow of the second medium 02.

[0023] Specifically, by setting end caps 1 at both ends and sequentially connecting multiple axial tube sheet modules 2 in between, each module is structurally independent yet forms a continuous whole in the medium path. This not only facilitates manufacturing and transportation but also allows for flexible combination according to different operating conditions, thereby achieving multi-stage heat exchange. In this embodiment, as shown... Figure 1 As shown, there are four sets of axial tube sheet modules 2 in the middle. Other numbers of axial tube sheet modules 2 can also be designed according to site requirements, all of which are within the protection scope of this application. In a preferred embodiment, the shell 21 can be cylindrical, or other shapes such as polygonal cross-sections. Its material can be carbon steel, stainless steel, titanium alloy, or composite corrosion-resistant metal, depending on the operating environment. The connection between the two vertical tube sheets 22 and the shell 21 can be a fully welded seal or a flange seal to meet the sealing reliability requirements under high pressure and high temperature conditions. Several first heat exchange tubes 23 penetrate the two vertical tube sheets 22 radially along the shell 21, and the tube ends are fixed to the tube sheets by expansion joints or welding to ensure structural stability and heat transfer efficiency. Several baffles 24 are provided at the end of the tube-side cavity 25 of each axial tube sheet module 2 to guide the first medium 01 to flow in a predetermined direction. Some baffles 24 are provided with connecting holes 241, allowing connections at different positions. The through-hole 241 allows the first medium 01 to form an approximately serpentine flow path in multiple modules. By rationally designing the distribution of perforated and non-perforated baffles 24, the first medium 01 can be made to turn back in each module in sequence, thereby extending the flow path of the medium and strengthening the disturbance, thus improving the heat transfer coefficient and reducing heat transfer dead zones. Two adjacent axial tube sheet modules 2 are interconnected through their adjacent shell-side cavities 26. The second medium 02 forms a continuous flow channel between the shell-side cavities 26 of each module. The shell-side connection can be achieved through external flange connection or embedded annular channel. Sealing rings can be set between modules. The sealing material is preferably fluororubber, polytetrafluoroethylene or graphite composite material, so that the module can still maintain a stable seal under high pressure, while facilitating later maintenance and replacement.

[0024] During operation, the first medium 01 enters the tube-side cavity 25 of the frontmost module through the first medium inlet 3, flows sequentially along the serpentine path formed inside the multiple axial tube sheet modules 2, and finally exits from the first medium outlet 4. The second medium 02 enters the shell-side flow channel through the second medium inlet 5, passes through the shell-side cavity 26 between adjacent modules, flows in a direction perpendicular to the first medium 01, and finally exits from the second medium outlet 6. The two media exchange heat on both sides of the heat exchange tube. The flow direction of the second medium 02 is set perpendicular to the first heat exchange tube 23. When the second medium 02 flows through the first heat exchange tube 23, it collides with the first heat exchange tube 23, which prolongs the residence time of the second medium 02 and improves the heat exchange efficiency.

[0025] Each axial tube sheet module 2 in this invention is equivalent to an independent BXM heat exchanger in a traditional system. By connecting multiple such modules in series along the axial direction, the original multiple heat exchangers are integrated. Compared with the traditional cross-flow heat exchange system formed by multiple devices connected in series, this invention achieves multi-stage heat exchange effect within the same device through a modular structure. This allows the heat exchange process that originally required multiple devices and complex external piping to be completed in a single device. Since each axial tube sheet module 2 has an independent tube-side cavity 25 and shell-side cavity 26, and the modules are interconnected... A continuous serpentine flow channel is formed through the connecting holes 241 of the partition 24, allowing the first medium 01 to flow back and forth sequentially within the module, thereby realizing the heat exchange path function of the original multi-stage equipment. This structure not only retains the heat transfer enhancement characteristics of multi-stage heat exchange, but also reduces the number of equipment and system connection points, avoiding uneven flow, leakage and structural stress concentration problems between multiple equipment. At the same time, the modular layout makes unit replacement and maintenance more convenient. Users can flexibly adjust the number of modules according to the working conditions to adapt to different heat exchange loads, realizing the equivalent heat exchange function of the original multi-equipment system in a compact space.

[0026] As a preferred embodiment, a second heat exchange tube 28 is arranged in a serpentine manner within the edge space 27 between the first heat exchange tube 23 and the shell 21. The second heat exchange tube 28 penetrates multiple axial tube sheet modules 2, and its inlet and outlet are respectively connected to the tube-side cavities 25 of the axial tube sheet modules 2 located at both ends, so that the first medium O1 circulates within the second heat exchange tube 28. Specifically, as shown... Figure 3 , 4As shown, since the edge space 27 formed by the first heat exchange tube 23 and the shell 21 is too small to directly install the first heat exchange tube 23, a serpentine second heat exchange tube 28 is designed in this edge space 27. This improves the utilization rate of the edge space 27 inside the equipment, transforming the gap area between the first heat exchange tube 23 and the shell 21 into an effective heat exchange channel, increasing the total heat transfer area. By arranging the second heat exchange tube 28 in a serpentine structure, the first medium 01 generates multiple back-and-forth movements and disturbances during the flow process, enhancing the mixing and turbulence of the first medium 01, reducing temperature stratification, and making the heat exchange more thorough and uniform. At the same time, the second heat exchange tube 28 runs through multiple modules to form a continuous path, enabling the first medium 01 to circulate and exchange heat inside the equipment. This not only extends the heat exchange path but also improves the overall heat exchange efficiency.

[0027] In this embodiment, the serpentine portion 281 of the second heat exchange tube 28 is formed within the same axial tube sheet module 2, or the serpentine portion 281 of the second heat exchange tube 28 is formed between adjacent axial tube sheet modules 2. Specifically, as shown... Figure 3 As shown, one specific implementation of the second heat exchange tube is illustrated, in which the serpentine rotating portion 281 of the second heat exchange tube 28 is formed within the same axial tube sheet module 2. When the serpentine rotating portion 281 is arranged within the same module, multiple flow reversals can be completed within a single module, increasing the residence time of the first medium 01 in the local area and enhancing the turbulence, thereby improving the heat transfer intensity and heat exchange efficiency of the single module. Another specific implementation of the second heat exchange tube (not shown) is that when the thickness of the axial tube sheet module 2 is relatively small and the diameter of the shell 21 is relatively large, the serpentine rotating portion 281 of the second heat exchange tube 28 can be formed between adjacent axial tube sheet modules 2. When passing through the module connection, it makes a reversal, so that the bending section crosses the boundary area of ​​the two modules, allowing the first medium 01 to achieve periodic flow reversal between the modules, extending the overall flow distance of the first medium 01, and realizing the expansion of the overall heat exchange area and the improvement of heat exchange efficiency. The two arrangement methods can be flexibly selected or combined according to the working conditions, so that ideal heat exchange effects can be obtained under different temperature differences, flow rates and installation edge space 27 conditions.

[0028] Among them, the first heat exchange tube 23 is a straight tube, as shown in the reference. Figure 4 As a first specific implementation of the first heat exchange tube 23, the first heat exchange tube 23 is a straight tube structure. The straight tube form of the first heat exchange tube 23 has the advantages of low flow resistance, high arrangement density, convenient processing and assembly, and reduced cost. It can form a regular and uniform tube bundle distribution within the limited edge space 27, making the fluid flow in the tube smoother and avoiding local pressure loss and fluid stagnation caused by the curved structure.

[0029] As a preferred embodiment, the first heat exchange tube 23 is a serpentine tube, with the serpentine rotation plane perpendicular to the axis of the housing 21, or the serpentine rotation plane is parallel to the axis of the housing 21, such as... Figure 5 As shown, in a second specific embodiment of the first heat exchange tube 23, the serpentine tube not only effectively extends the length of the first heat exchange tube 23 within the shell 21, but also increases the heat exchange area, thereby enhancing the heat exchange between the two media. Furthermore, the flow direction of the second medium 02 is perpendicular to the serpentine rotation plane. During the flow process, the fluid will continuously collide and split with the surface of the serpentine tube, causing multiple disturbances to the fluid within the shell side. The flow path continuously changes direction, thereby enhancing the turbulence intensity and fluid mixing effect of the second medium 02 on the shell side. Due to the staggered impact and shearing action between the second medium 02 and the surface of numerous serpentine tubes in the flow channel, the heat transfer boundary layer of the second medium 02 on the shell side is periodically broken and renewed, greatly improving the convective heat transfer coefficient. The multiple rotations of the serpentine tube not only extend the heat exchange path but also multiply the heat transfer area within the limited edge space 27, which is beneficial for improving the heat transfer efficiency per unit volume. Figure 6 As shown, the third specific implementation of the first heat exchange tube 23 is that the serpentine rotation plane of the serpentine tube is set parallel to the axis of the shell 21, which also extends the flow distance of the fluid, increases the heat exchange area per unit volume, and causes the fluid to turn, accelerate and mix multiple times in the tube, thereby improving the degree of turbulence and the local heat transfer coefficient.

[0030] As a preferred embodiment of the above, the first heat exchange tubes 23 are arranged in a staggered manner between adjacent layers.

[0031] One specific implementation method for the first heat exchange tube 23 is a staggered arrangement between adjacent layers, such as... Figure 7 As shown, the axial tube sheet module 2 is provided with two sets of vertical tube sheets 22 that are perpendicular to each other. The first heat exchange tube 23 is respectively arranged between the two sets of vertical tube sheets 22, forming two tube-side flow channels and one shell-side flow channel. The two tube-side flow channels are independent of each other or connected in series. Specifically, each module has four vertical tube sheets 22, and the two sets of vertical tube sheets 22 are arranged vertically to form two tube sides. These two tube sides can be independent of each other or connected in series, which are all within the protection scope of this application.

[0032] On the one hand, by setting two sets of mutually perpendicular vertical tube plates 22 within the same module, and arranging the first heat exchange tubes 23 between the two sets of vertical tube plates 22 respectively, a single module can form two independent tube-side flow channels and one shell-side flow channel, resulting in a more compact structure. On the other hand, the heat exchange tubes are arranged between the two sets of vertical tube plates 22, allowing the tube side to be arranged in sections on the shell 21 cross-section. When the second medium 02 flows between the two shell-side regions, it generates more lateral impact and turbulence, improving the flow field distribution and thus increasing the heat transfer coefficient and effective heat transfer area utilization rate on the shell side. Furthermore, the two sets of mutually perpendicular vertical tube plates 22 form a U-shaped support within the shell 21, acting as internal reinforcing ribs. This facilitates the uniform transmission of internal pressure loads, reduces stress concentration in the shell 21 and tube plate areas, improves deformation resistance and fatigue life, and enhances the reliability of equipment operation.

[0033] Another specific implementation of the staggered arrangement between adjacent layers of the first heat exchange tube 23 is as follows: when there are only two vertical tube plates 22, the adjacent two layers of first heat exchange tubes 23 can be staggered in spatial position, that is, the two adjacent first heat exchange tubes 23 are not vertically aligned. For the second medium 02, it will alternately contact and impact the outer wall of the serpentine tubes of different layers during the shell-side flow, so the flow path is fluctuating, which enhances the disturbance and mixing effect of the fluid and makes the temperature field distribution in the shell-side more uniform.

[0034] As a preferred embodiment of the above, such as Figure 8 As shown, a buffer structure 221 is provided on the vertical tube sheet 22. The buffer structure 221 is located at the connection between the inner side of the shell 21 and the vertical tube sheet 22. The buffer structure 221 is configured to compensate for the alignment error between the heat exchange tubes by the local slight deformation of the tube sheet when welding multiple heat exchange tubes to the tube sheet, so as to prevent welding stiffness.

[0035] The buffer structure 221 is an inclined or arc-shaped section set along the edge connecting the inner wall of the shell 21 and the vertical tube plate 22. The inclined or arc-shaped section is set at an inclination and distributed in a figure-eight shape, forming a controllable flexible zone between the vertical tube plate 22 and the shell 21. When multiple first heat exchange tubes 23 have slight alignment errors with the tube plate holes due to manufacturing tolerances, this structure allows the tube plate to undergo a small amount of elastic adaptive deformation, thereby absorbing and compensating for this error. This fundamentally avoids the generation of residual assembly stress inside the tube body during the welding and fixing process, and greatly improves the welding quality and reliability.

[0036] As a preferred embodiment of the above, such as Figure 9As shown, transition angles 241a are provided on both sides of the connecting hole 241 to guide the flow of the first medium 01 and reduce resistance. Specifically, when the first medium 01 switches between adjacent modules along the pipe flow channel through the connecting hole 241, the guiding effect of the transition angle 241a makes the fluid streamline conform to the hole wall for a smooth transition, thereby reducing the local pressure drop caused by the abrupt change of direction.

[0037] The present invention also includes a method for operating the axial tube sheet module 2 combined heat exchanger as described above, comprising: S10: The first medium 01 is introduced from the first medium inlet 3, so that the first medium 01 flows sequentially along the tube flow channels in the multiple axial tube sheet modules 2, and forms an approximately serpentine flow path through the partition 24 with the connecting hole 241. S20: The second medium 02 is introduced from the second medium inlet 5 and flows perpendicularly to the first medium 01 along the shell-side flow channel for heat exchange. S30: The first medium 01 and the second medium 02 after heat exchange are discharged from the corresponding first medium outlet 4 and second medium outlet 6, respectively. The positions of the first medium inlet 3 and the first medium outlet 4 can be interchanged as needed; correspondingly, the positions of the second medium inlet 5 and the second medium outlet 6 can also be interchanged as needed, thereby achieving overall parallel or counter-current heat exchange.

[0038] Specifically, the first medium 01 enters through the first medium inlet 3 and flows sequentially along the tube-side channels within multiple axial tube sheet modules 2. Guided by the connecting holes 241 on the partition plates 24 of each module, it forms an approximately serpentine flow path, thereby extending the fluid flow distance, increasing the heat exchange area and contact time with the tube wall, making the flow within the tube side more thorough and uniform, and improving heat exchange efficiency. The second medium 02 enters through the second medium inlet 5 and continuously traverses multiple modules in the direction intersecting with the first medium 01, forming a multi-stage cross-flow or cross-current heat exchange structure. The fluid within the shell side... As the medium flows through the tube bundle, it is constantly disturbed and mixed, which enhances the convective heat transfer effect. After heat exchange, the two media are discharged from their respective outlets, completing the energy transfer process. Through the above working method, the flow of the first medium 01 and the second medium 02 in the tube side and shell side are coupled with each other, which not only ensures the sufficiency of heat exchange, but also reduces the overall pressure drop and energy loss. Compared with the traditional method of multiple heat exchangers operating in series, this method has a compact structure, high energy efficiency, low flow resistance, reduces external connection pipelines and potential leakage points, and improves the safety, stability and maintenance convenience of the system operation.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An axial tube sheet modular heat exchanger, characterized in that, The application relates to a heat exchanger, comprising: two end covers, a plurality of axial tube plate modules arranged in series between the two end covers, a first medium inlet and a first medium outlet located at the axial tube plate modules at two ends, and a second medium inlet and a second medium outlet arranged on the two end covers respectively; the axial tube plate module comprises a shell, at least two vertical tube plates arranged in the shell and axially parallel to the shell, and a plurality of first heat exchange tubes penetrating through the two vertical tube plates; the two vertical tube plates divide the shell into a middle shell-side cavity and two tube-side cavities located at two sides of the shell-side cavity; the inner cavity of the first heat exchange tube constitutes part of a tube-side flow channel, the end of the tube-side cavity is provided with a partition plate, part of the partition plate is provided with a communication hole, and the tube-side flow channel is sequentially communicated in the plurality of axial tube plate modules through the partition plates provided with the communication holes and the partition plates not provided with the communication holes, so that an approximate serpentine path for circulating the first medium is formed; two adjacent axial tube plate modules are communicated through their adjacent shell-side cavities and jointly constitute a shell-side flow channel for circulating the second medium. The edge space between the first heat exchange tube and the shell is provided with a second heat exchange tube arranged in a serpentine rotary manner, the second heat exchange tube penetrates through the plurality of axial tube plate modules, and the inlet and the outlet of the second heat exchange tube are connected with the shell-side cavities of the axial tube plate modules at two ends respectively, so that the first medium circulates and flows in the second heat exchange tube. The serpentine rotary part of the second heat exchange tube is formed in the same axial tube plate module, or the serpentine rotary part of the second heat exchange tube is formed between adjacent axial tube plate modules. The first heat exchange tube is a straight tube. The first heat exchange tube is a serpentine tube, the serpentine rotary plane of the serpentine tube is arranged perpendicular to the axis of the shell, or the serpentine rotary plane of the serpentine tube is arranged parallel to the axis of the shell. The first heat exchange tube is arranged in a staggered manner between adjacent layers.

2. The axial tube sheet modular heat exchanger of claim 1, wherein, The axial tube plate module is provided with two groups of vertical tube plates perpendicular to each other, the first heat exchange tubes are arranged between the two groups of vertical tube plates respectively, two tube-side flow channels and one shell-side flow channel are formed, and the two tube-side flow channels are independent of each other or are connected in series.

3. The axial tube sheet modular heat exchanger of claim 2, wherein, The vertical tube plate is provided with a buffer structure at the connection between the inner side of the shell and the vertical tube plate.

4. The axial tube-on-plate modular heat exchanger of claim 1, wherein, The buffer structure is an inclined section or a circular arc section arranged along the connecting edge of the vertical tube plate and the inner wall of the shell, and the inclined section or the circular arc section is arranged in an inclined manner and in an eight-shaped distribution.

5. The axial tube-on-plate modular heat exchanger of claim 1, wherein, The application further relates to a heat exchange method, comprising the following steps: introducing the first medium from the first medium inlet, making the first medium flow in the tube-side flow channels in the plurality of axial tube plate modules in sequence, and forming an approximate serpentine flow path through the partition plates provided with the communication holes; introducing the second medium from the second medium inlet, making the second medium cross-flow with the first medium along the shell-side flow channel, and performing heat exchange; and discharging the first medium and the second medium after heat exchange from the corresponding first medium outlet and the second medium outlet respectively.

6. The axial tube-on-plate modular heat exchanger of claim 1, wherein, ​ 7. The axial tube-on-plate modular heat exchanger of claim 6, wherein, ​ 8. The axial tube-on-plate modular heat exchanger of claim 1, wherein, ​ 9. The axial tube-on-plate modular heat exchanger of claim 8, wherein, ​ 10. A method of operating an axial-tube-sheet modular heat exchanger as defined in claim 1, wherein, ​ ​ ​ ​ The first medium inlet and the first medium outlet interchange positions as needed; correspondingly, the second medium inlet and the second medium outlet interchange positions as needed, so as to realize parallel flow or counter flow heat exchange as a whole.

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