Waste heat recovery heat exchanger

Abstract

The utility model relates to a waste heat recovery heat exchanger, and relates to the field of waste heat recovery technology, the waste heat recovery heat exchanger comprises a shell, the shell is provided with a fluid inlet, a fluid outlet and a heat exchange cavity, the heat exchange cavity is internally provided with an inner ring heat exchange tube set and an outer ring heat exchange tube set from inside to outside, and the fluid inlet is communicated with the heat exchange cavity through a central tube; and the high-temperature fluid enters the heat exchange cavity through the fluid inlet and the central pipe, is cooled after being subjected to radiation type heat exchange with the inner ring heat exchange pipe group and the outer ring heat exchange pipe group, and is discharged from the fluid outlet. According to the heat exchanger, the design of the inner-ring heat exchange pipe set and the outer-ring heat exchange pipe set is adopted, fluid is subjected to sufficient heat exchange with the pipe walls through radiation type heat exchange when flowing through the heat exchanger, so that heat transfer between high-temperature fluid and cooling fluid is more efficient, and the heat exchange efficiency is improved; and the flow path is simple and direct, the loss is reduced, and the consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste heat recovery technology, in particular to a waste heat recovery heat exchanger. BACKGROUND

[0002] With the promotion of the global "double carbon" goal, green ammonia, as a potential carbon-free fuel, has gradually become an important choice in the field of clean energy due to its high energy density, liquid state at room temperature and normal pressure, easy storage and transportation. Compared with hydrogen, green ammonia has significant advantages in storage and transportation, and can be used for fuel cell power generation or directly as an internal combustion engine fuel, providing clean energy for transportation and distributed power generation, and is expected to promote the transformation of energy from traditional fossil fuels to renewable energy.

[0003] In the production process of green ammonia, the waste heat recovery system of synthetic ammonia is the key to improving energy utilization efficiency. Most current waste heat recovery devices use traditional kettle U-tube heat exchanger structures. However, the traditional structure has some limitations, which affects the overall energy utilization efficiency and reduces the production cost.

[0004] Firstly, due to the limitation of the curvature radius of the elbow pipe, the arrangement of the heat exchange pipe is less, and the inner layer pipe spacing in the pipe bundle is larger, which leads to low effective utilization rate of the tube sheet. This limits the heat exchange area of the heat exchanger, reduces the heat exchange capacity, and thus affects the energy recovery efficiency.

[0005] Secondly, the larger spacing of the innermost layer of the pipe bundle is easy to cause short circuit of the shell side fluid during flow, that is, part of the fluid directly flows through the pipe bundle gap without sufficient heat exchange, which not only reduces the heat transfer efficiency of the shell side, but also wastes heat, affecting the heat exchange effect of the whole heat exchanger. In addition, the flow dead angle is easy to form between the inner wall of the pipe box and the pipe bundle in the traditional structure, which reduces the flow rate and causes impurities and precipitates to accumulate, forming fouling, which further affects the heat exchange efficiency.

[0006] In addition, in the high temperature and high pressure environment of the traditional U-tube heat exchanger, due to the temperature difference between the tube side and the shell side, the thermal expansion of the equipment may not be effectively compensated, which may cause deformation of the equipment, loosening of the connection between the pipe bundle and the tube sheet, and even may cause leakage problem, which seriously affects the stable operation of the equipment.

[0007] Therefore, the design and structure of the traditional kettle U-tube heat exchanger have many problems in the production process of synthetic ammonia, and it is urgent to optimize the design to improve the heat exchange efficiency, reduce the energy consumption and enhance the stability of the equipment. CONTENT OF THE INVENTION

[0008] In order to improve the heat exchange efficiency, reduce the energy consumption and enhance the stability of the equipment, the present application provides a waste heat recovery heat exchanger.

[0009] The waste heat recovery heat exchanger provided by the application adopts the following technical scheme:

[0010] A waste heat recovery heat exchanger for waste heat recovery of high-temperature fluid, comprising a shell provided with a fluid inlet, a fluid outlet and a heat exchange cavity, wherein an inner circle heat exchange pipe group and an outer circle heat exchange pipe group are arranged in the heat exchange cavity from inside to outside, and the fluid inlet is communicated with the heat exchange cavity through a center pipe; the high-temperature fluid enters the heat exchange cavity through the fluid inlet and the center pipe, and is cooled after radiation heat exchange with the inner circle heat exchange pipe group and the outer circle heat exchange pipe group, and is discharged through the fluid outlet.

[0011] By adopting the above technical scheme, by adopting the design of the inner and outer circle heat exchange pipe groups, the fluid fully exchanges heat with the pipe wall through radiation heat exchange when flowing through the heat exchanger, so that the heat transfer between the high-temperature fluid and the cooling fluid is more efficient, and the heat exchange efficiency is improved; and by adopting the center pipe inlet mode, the fluid can smoothly flow to each heat exchange pipe group after entering from the center pipe, the flow path is simple and direct, thereby reducing the local resistance loss and reducing the power consumption required for the fluid to flow in the waste heat recovery device; in addition, the design of the inner and outer circle arrangement can effectively save space, reduce the floor area occupied by the heat exchanger, and improve the compactness and stability of the equipment, and enhance the stability of the equipment under external vibration, pressure fluctuation and the like.

[0012] In a specific implementable scheme, the inner circle heat exchange pipe group and the outer circle heat exchange pipe group are arranged concentrically.

[0013] By adopting the above technical scheme, the concentric structure of the inner heat exchange pipe group and the outer circle heat exchange pipe group makes the airflow channel inside the heat exchanger uniform, and the heat exchange area between the pipe surfaces is maximized, ensuring that the heat transfer from the fluid to the pipe wall is more sufficient, and improving the overall heat exchange efficiency of the heat exchanger; and the structure of the heat exchanger is more compact, not only saving the volume and floor area of the equipment, but also making the structure of the heat exchanger more stable, facilitating installation and maintenance.

[0014] In a specific implementable scheme, an inner tube plate and an outer tube plate are arranged between the center pipe and the heat exchange cavity, a separation cavity is arranged between the inner tube plate and the outer tube plate, the inner circle heat exchange pipe group and the outer circle heat exchange pipe group are fixed on the inner tube plate and the outer tube plate respectively, the inner tube plate is provided with an air inlet pipe, the center pipe is communicated with the air inlet pipe, the air inlet pipe extends into the inner circle heat exchange pipe group, the outer circle heat exchange pipe group is communicated with the separation cavity, the outer tube plate is provided with an opening, and the separation cavity is communicated with the fluid outlet through the opening.

[0015] By adopting the technical scheme, in the design, the fluid first passes through the inner ring heat exchange pipe group for preliminary cooling, and then passes through the outer ring heat exchange pipe group for further temperature reduction, and the segmented heat exchange mode ensures that the heat exchange of each stage is fully utilized, and the structure of the inner and outer ring heat exchange pipe groups can increase the heat exchange area and improve the heat exchange efficiency.

[0016] In a specific implementable embodiment, an expansion joint is further included, and the fluid inlet is connected to the central pipe through the expansion joint.

[0017] By adopting the technical scheme, the expansion joint can effectively absorb the pipe thermal expansion caused by temperature change, and can reduce the stress of the pipe during the flow of high-temperature fluid, avoid pipe deformation or damage caused by thermal expansion, and prolong the service life of the equipment.

[0018] In a specific implementable embodiment, the central pipe includes a straight pipe section and a gradually expanding pipe section, the expansion joint is connected to the straight pipe section, and the gradually expanding pipe section is arranged close to the heat exchange cavity.

[0019] By adopting the technical scheme, after the fluid enters the central pipe from the inlet, the diameter of the pipe is gradually increased, the flow rate of the fluid is reduced, the flow resistance inside the pipe is reduced, the fluid is evenly distributed to each heat exchange pipe, the power consumption required for the fluid to flow in the heat recovery device is reduced, and the heat exchange efficiency is optimized.

[0020] In a specific implementable embodiment, a cooling water inlet is further included, a water storage cavity is formed between the inner and outer walls of the shell, the cooling water inlet is in communication with the water storage cavity, and the water storage cavity is arranged along the circumferential side of the heat exchange cavity.

[0021] By adopting the technical scheme, after the cooling water enters the water storage cavity, it starts to contact the inner and outer ring heat exchange pipe groups, the high-temperature fluid flows through the heat exchange pipe, and the cooling water absorbs heat by contacting the heat exchange pipe wall and can efficiently exchange heat with the heat exchange pipe of the high-temperature synthetic ammonia gas. The arrangement of the water storage cavity helps to improve the uniformity of the cooling water flow, thereby improving the heat exchange efficiency and ensuring the long-term stable operation of the equipment.

[0022] In a specific implementable embodiment, a steam-water separator and a steam outlet are further included, the steam-water separator is used to separate the steam-water mixture formed after heat exchange, and the separated steam is discharged through the steam outlet.

[0023] By adopting the above technical scheme, in the heat exchange process, the shell transmits the high-temperature three-dimensional heat to the cooling water in the water storage cavity, the cooling water contacts the pipe wall to generate multiple turns and disturbances, the cooling water continuously absorbs heat to become a steam-water mixture, the steam-water separator separates the mixture to remove the water therein and separates out pure steam; after being treated by the steam-water separator, the pure steam is discharged through the steam outlet, and the steam can be used for subsequent industrial processes, power generation and other applications.

[0024] In a specific implementable embodiment, the overall outer edge shape of the inner circle heat exchange pipe group is hexagonal.

[0025] By adopting the above technical scheme, the hexagonal arrangement can fully utilize the space and provide better fluid flow distribution, reduce fluid dead zones, optimize fluid flow and heat exchange effect, thereby improving the performance of the entire heat exchanger.

[0026] In a specific implementable embodiment, the overall inner edge shape and the overall outer edge shape of the outer circle heat exchange pipe group are both hexagonal.

[0027] By adopting the above technical scheme, the outer circle heat exchange pipe group adopts the combination of the hexagonal outer edge shape and the inner edge shape, which can maximize the utilization rate of space, reduce the volume of the heat exchanger, increase the heat exchange surface area between the heat exchange pipes, ensure the uniformity of fluid flow, reduce flow dead zones, and improve heat exchange efficiency.

[0028] In a specific implementable embodiment, the inner circle heat exchange pipe group and the outer circle heat exchange pipe group are both composed of a plurality of U-shaped heat exchange pipes.

[0029] By adopting the above technical scheme, the structure of the U-shaped pipe is conducive to increasing the residence time of the fluid and the heat exchange area with the pipe wall, which can effectively improve the heat transfer efficiency, especially when the fluid flow speed is low, which is conducive to better heat exchange.

[0030] In summary, the present application includes at least one of the following beneficial technical effects:

[0031] 1. The inner and outer circle radiation type pipe arrangement is adopted, the flow direction and speed of the gas and water are constantly changed, the heat transfer effect is enhanced, the heat transfer coefficient is improved; at the same time, the contact opportunity of the cooling water with the heat exchange pipe is increased, the convective heat transfer coefficient on the water side is improved, and the inverse flow heat exchange mode is approached;

[0032] 2. The inner and outer circle radiation type pipe arrangement optimizes the space utilization, increases the number of heat exchange pipes and the heat transfer area, improves the waste heat recovery efficiency, improves the system stability, reduces the faults caused by vibration and thermal stress, and prolongs the service life of the equipment;

[0033] 3. The gradual expansion of the center tube inlet design reduces fluid flow rate, reduces local impact, improves fluid distribution uniformity, and reduces energy consumption;

[0034] 4. The design of the pipe expansion joint can absorb thermal expansion stress, prevent pipe rupture and leakage in high temperature and high pressure environment, and greatly improve the safety and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a structural schematic diagram of the waste heat recovery heat exchanger of the embodiment of the present application.

[0036] Figure 2 is a structural schematic diagram for showing the inner circle heat exchange tube group and the outer circle heat exchange tube group.

[0037] Figure 3 is a structural schematic diagram for showing the fluid inlet, the center tube, the expansion joint, the inner tube plate, and the outer tube plate.

[0038] BRIEF DESCRIPTION OF DRAWINGS: 1, shell; 11, pipe box; 12, kettle body; 13, fluid inlet; 14, fluid outlet; 15, heat exchange cavity; 16, cooling water inlet; 17, water storage cavity; 18, steam outlet; 2, inner circle heat exchange tube group; 3, outer circle heat exchange tube group; 4, expansion joint; 5, center tube; 51, straight tube section; 52, gradual expansion type tube section; 6, steam-water separator; 7, inner tube plate; 71, air inlet pipe; 8, outer tube plate; 9, partition cavity. DETAILED DESCRIPTION

[0039] The following will be described in detail in combination with the accompanying Figures 1-3 Further detailed description will be made to the present application.

[0040] Reference Figure 1 and Figure 2 , the embodiment of the present application discloses a waste heat recovery heat exchanger for waste heat recovery of high temperature fluid, which is not limited to be applied to waste heat recovery of synthetic ammonia in the embodiment, and the temperature of the synthetic ammonia can be as high as 400-600℃;

[0041] The waste heat recovery heat exchanger comprises a shell 1, in the embodiment, the shell 1 is horizontally arranged, the shell 1 is composed of a pipe box 11 and a kettle body 12, the shell 1 is provided with a fluid inlet 13, a fluid outlet 14 and a heat exchange cavity 15, in the embodiment, the fluid inlet 13 and the fluid outlet 14 are vertically arranged on the pipe box 11, the heat exchange cavity 15 is arranged in the kettle body 12, and the fluid inlet 13, the fluid outlet 14 and the heat exchange cavity 15 are in communication;

[0042] The fluid inlet 13 is connected with the heat exchange cavity 15 through the central pipe 5. In the embodiment, the central pipe 5 is horizontally arranged in the pipe box 11, and the central pipe 5 introduces the high-temperature fluid into the heat exchange cavity 15. In the direct introduction mode of the central pipe 5, the fluid can smoothly flow to each heat exchange pipe group after entering the central pipe 5, and the flow path is simple and direct, thereby reducing the local resistance loss and reducing the power consumption required for the fluid to flow in the waste heat recovery device;

[0043] The inner circle heat exchange pipe group 2 and the outer circle heat exchange pipe group 3 are arranged in the heat exchange cavity 15 along the radial direction of the kettle body 12 from inside to outside, and both are horizontally arranged, and the inner and outer circle pipes are arranged around. The high-temperature fluid exchanges heat with the pipe wall through the two groups of pipes, thereby realizing waste heat recovery.

[0044] The inner circle heat exchange pipe group 2 and the outer circle heat exchange pipe group 3 are arranged concentrically. The concentric structure of the inner heat exchange pipe group and the outer circle heat exchange pipe group 3 makes the airflow channel in the heat exchanger uniform, and the heat exchange area between the pipe surfaces is maximized, which ensures that the heat transfer from the fluid to the pipe wall is more sufficient. The optimized layout of the concentric structure effectively improves the overall heat exchange efficiency of the heat exchanger. The design of the concentric pipe layout makes the structure of the heat exchanger more compact, and the space utilization between the pipes is more efficient. Not only the volume and the floor area of the equipment are saved, but also the structure of the heat exchanger is more stable, which is convenient for installation and maintenance.

[0045] During work, the high-temperature fluid enters the heat exchanger from the fluid inlet 13, and flows into the heat exchange cavity 15 through the central pipe 5. The central pipe 5 directly guides the high-temperature fluid to the inner circle heat exchange pipe group 2. Then, the fluid is preliminarily cooled after the heat exchange process of the inner circle heat exchange pipe group 2. The fluid enters the outer circle heat exchange pipe group 3 after flowing out of the inner circle heat exchange pipe group 2, and continues to be cooled and further transfers heat to the pipe wall through radiation heat exchange.

[0046] During the whole heat exchange process, the design of the inner circle heat exchange pipe group 2 and the outer circle heat exchange pipe group 3 realizes efficient heat transfer. The radiation heat exchange process between the inner and outer circle pipes and the fluid effectively reduces the temperature of the fluid, improves the working efficiency of the heat exchanger, and finally, the cooled fluid is discharged from the heat exchanger through the fluid outlet 14. Through the reasonable layout of the inner and outer circle heat exchange pipe groups, the fluid can obtain sufficient heat exchange in the heat exchanger, enhance the efficiency of heat transfer, improve the heat exchange effect, and reduce energy loss.

[0047] In addition, the design of the inner and outer circle arrangement can effectively save space, reduce the floor area of the heat exchanger, and improve the compactness and stability of the equipment. The inner and outer circle structure improves the heat load bearing capacity of the equipment, which is beneficial to increase the processing capacity of the heat exchanger. The design of the inner and outer circle heat exchange pipe groups also provides a more stable structure, which enhances the stability of the equipment under external vibration, pressure fluctuation and other conditions.

[0048] Referring toFigure 1 And Figure 3 In the embodiment, the expansion joint 4 is arranged vertically, and is arranged between the fluid inlet 13 and the central pipe 5 and communicates the fluid inlet 13 and the central pipe 5. The expansion joint 4 can effectively absorb the thermal expansion of the pipe caused by temperature change, reduce the stress of the pipe, and avoid deformation or damage of the pipe due to thermal expansion. This not only improves the service life of the equipment, but also enhances the stability of the heat exchanger in a high-temperature working environment.

[0049] In the embodiment, the central pipe 5 includes a straight pipe section 51 and a gradually expanding pipe section 52. The gradually expanding pipe section 52 gradually increases in diameter from one side close to the expansion joint 4 to one side close to the heat exchange cavity 15. After the fluid enters the central pipe 5 from the fluid inlet 13, the fluid gradually enters the gradually expanding pipe section 52 after passing through the straight pipe section 51. The diameter of the pipe gradually increases, and the flow rate of the fluid gradually decreases. This design reduces the flow resistance, ensures that the fluid can be uniformly distributed to each heat exchange pipe group, improves the heat exchange effect of the fluid, and effectively reduces the energy consumption and wear of the system.

[0050] The inner tube plate 7 and the outer tube plate 8 are arranged between the central pipe 5 and the heat exchange cavity 15. In the embodiment, the inner tube plate 7 and the outer tube plate 8 are fixed by bolts, and a partition cavity 9 is formed between the inner tube plate 7 and the outer tube plate 8. One end of the inner circle heat exchange pipe group 2 and the outer circle heat exchange pipe group 3 is fixed on the inner tube plate 7 and the outer tube plate 8, respectively. The inner tube plate 7 is provided with an air inlet pipe 71, the central pipe 5 communicates with the air inlet pipe 71, the air inlet pipe 71 extends into the inner circle heat exchange pipe group 2, the outer circle heat exchange pipe group 3 communicates with the partition cavity 9, and the outer tube plate 8 is provided with an opening. The partition cavity 9 communicates with the fluid outlet 14 through the opening.

[0051] In the working process, the high-temperature fluid first enters the inner circle heat exchange pipe group 2 through the air inlet pipe 71, is cooled, and then flows to the outer circle heat exchange pipe group 3 for further cooling. The outer circle heat exchange pipe group 3 is connected with the partition cavity 9, the cooled fluid is connected with the fluid outlet 14 through the opening in the partition cavity 9, and finally discharged from the heat exchanger. In this design, the fluid is first cooled by the inner circle heat exchange pipe group 2, and then further cooled by the outer circle heat exchange pipe group 3. This segmented heat exchange mode ensures that the heat exchange at each stage is fully utilized. The structure of the inner and outer circle heat exchange pipe groups can increase the heat exchange area and improve the heat exchange efficiency.

[0052] Referring to Figure 1 And Figure 2In the embodiment, the inner circle heat exchange pipe group 2 and the outer circle heat exchange pipe group 3 are both composed of several U-shaped heat exchange pipes; the design of the U-shaped pipes makes the fluid stay in the pipes for a longer time, increases the heat exchange area with the pipe wall, and effectively improves the heat transfer efficiency; and the bending structure of the U-shaped pipes further makes the pipeline layout more compact, facilitates the installation of more heat exchange pipes in a limited space, improves the heat exchange surface area, and thus improves the overall heat exchange efficiency of the heat exchanger.

[0053] To further improve the heat exchange efficiency and space utilization, the overall outer edge of the inner circle heat exchange pipe group 2 and the overall inner and outer edges of the outer circle heat exchange pipe group 3 in the embodiment are arranged in a hexagonal pattern; the hexagonal arrangement maximizes the space utilization between the heat exchange pipe groups, reduces the gap between the pipes, improves the uniformity of the fluid flow, optimizes the heat exchange effect, and the compactness of the hexagonal structure also reduces the floor area of the heat exchanger and improves the overall stability of the equipment.

[0054] Referring to Figure 1 The heat exchanger further comprises a cooling water inlet 16, and a water storage cavity 17 is formed between the inner and outer walls of the shell 1; in the embodiment, the water storage cavity 17 is formed between the inner and outer walls of the kettle body 12, the cooling water inlet 16 is in communication with the water storage cavity 17, and the water storage cavity 17 is arranged around the periphery of the heat exchange cavity 15; after the cooling water enters the water storage cavity 17, the high-temperature fluid flows through the heat exchange pipes, and the cooling water absorbs heat by contacting the heat exchange pipe wall, so that the cooling water can efficiently exchange heat with the heat exchange pipes of the high-temperature synthetic ammonia gas; the arrangement of the water storage cavity 17 helps to improve the uniformity of the cooling water flow, thereby improving the heat exchange efficiency and ensuring the long-term stable operation of the equipment;

[0055] The heat exchanger further comprises a steam-water separator 6 and a steam outlet 18; the steam-water separator 6 is used for separating the steam-water mixture formed after heat exchange, and the separated mixture is discharged through the steam outlet 18;

[0056] In operation, the high-temperature fluid enters the heat exchanger through the fluid inlet 13, enters the center pipe 5 through the expansion joint 4, and then enters the inner circle heat exchange pipe group 2 through the inlet pipe 71; after the fluid is cooled in the inner circle heat exchange pipe group 2, it flows to the outer circle heat exchange pipe group 3 for further cooling, and the heat is transferred to the pipe wall through radiation heat exchange;

[0057] In the heat exchange process, the cooling water enters the water storage cavity 17, the heat of the high-temperature fluid in the heat exchange cavity 15 of the kettle body 12 is transferred to the cooling water in the water storage cavity 17, the cooling water contacts the pipe wall and is repeatedly turned and disturbed, and the cooling water continuously absorbs heat, so that the cooling water can efficiently exchange heat with the heat exchange pipes of the high-temperature synthetic ammonia gas to achieve cooling;

[0058] In this process, the cooling water will form a mixture of steam and water, and then enter the upper end of the steam-water separator 6 for separation, the steam-water separator 6 can effectively separate the generated steam-water mixture, remove the moisture, leave the pure steam, and finally discharge through the steam outlet 18; The dry steam discharged can be further used in industrial processes or power generation systems to improve energy utilization efficiency, and the arrangement of the steam-water separator 6 not only ensures the quality of the steam, but also ensures the long-term stable operation of the equipment.

[0059] The waste heat recovery heat exchanger of the present application, after technical transformation, adopts inner and outer ring arrangement of heat exchange pipe group, the heat transfer coefficient can be increased by 20%-30%, under the same heat transfer area requirement, the volume can be reduced by 30%-40%, the cost can be reduced by 20%-30%;

[0060] The waste heat recovery heat exchanger of the present application adopts inner and outer ring radiation type pipe arrangement, not only enhances the heat exchange effect of gas and water, improves the heat transfer coefficient by 20%-30%, but also optimizes the space utilization, increases more heat exchange pipes in limited space, and improves the heat transfer area, so as to more efficiently recover the waste heat in the synthesis ammonia process; At the same time, the inner and outer ring structure provides better stability, reduces the failure risk caused by vibration and deformation; The gradually expanding center pipe 5 design reduces the flow rate of the fluid, reduces the local impact and flow unevenness, thereby reducing power consumption; The arrangement of the pipe expansion joint 4 effectively absorbs the stress caused by thermal expansion, enhances the stability of the system, and reduces the damage risk of the pipeline caused by thermal stress; The overall scheme optimizes the heat transfer efficiency, energy saving and consumption reduction, improves the system stability, prolongs the service life of the equipment, and effectively reduces the failure risk.

[0061] The above are preferred embodiments of the present application, not limited to the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A waste heat recovery heat exchanger for waste heat recovery of a high temperature fluid, characterized by: The application relates to a high-temperature fluid radiative heat exchange device, which comprises a shell (1) provided with a fluid inlet (13), a fluid outlet (14) and a heat exchange cavity (15), wherein an inner ring heat exchange pipe group (2) and an outer ring heat exchange pipe group (3) are arranged in the heat exchange cavity (15) from inside to outside, and the fluid inlet (13) is communicated with the heat exchange cavity (15) through a center pipe (5); high-temperature fluid enters the heat exchange cavity (15) through the fluid inlet (13) and the center pipe (5), is radiatively heat exchanged with the inner ring heat exchange pipe group (2) and the outer ring heat exchange pipe group (3) to be cooled, and is discharged through the fluid outlet (14).

2. The waste heat recovery heat exchanger of claim 1, wherein: The inner ring heat exchange pipe group (2) and the outer ring heat exchange pipe group (3) are concentrically arranged.

3. The waste heat recovery heat exchanger of claim 1, wherein: The center pipe (5) and the heat exchange cavity (15) are provided with an inner pipe plate (7) and an outer pipe plate (8), the inner pipe plate (7) and the outer pipe plate (8) are provided with a partition cavity (9), the inner ring heat exchange pipe group (2) and the outer ring heat exchange pipe group (3) are fixed on the inner pipe plate (7) and the outer pipe plate (8) respectively, the inner pipe plate (7) is provided with an air inlet pipe (71), the center pipe (5) is communicated with the air inlet pipe (71), the air inlet pipe (71) extends into the inner ring heat exchange pipe group (2), the outer ring heat exchange pipe group (3) is communicated with the partition cavity (9), the outer pipe plate (8) is provided with an opening, and the partition cavity (9) is communicated with the fluid outlet (14) through the opening.

4. The waste heat recovery heat exchanger of claim 1, wherein: The application further comprises an expansion joint (4), and the fluid inlet (13) is connected with the center pipe (5) through the expansion joint (4).

5. The waste heat recovery heat exchanger of claim 4, wherein: The center pipe (5) comprises a straight pipe section (51) and a gradually expanding pipe section (52), the expansion joint (4) is connected with the straight pipe section (51), and the gradually expanding pipe section (52) is arranged close to the heat exchange cavity (15).

6. The waste heat recovery exchanger of claim 1, wherein: The application further comprises a cooling water inlet (16), a water storage cavity (17) is formed between the inner wall and the outer wall of the shell (1), the cooling water inlet (16) is communicated with the water storage cavity (17), and the water storage cavity (17) is arranged along the circumferential side of the heat exchange cavity (15).

7. The waste heat recovery heat exchanger of claim 6, wherein: The application further comprises a steam-water separator (6) and a steam outlet (18), the steam-water separator (6) is used for separating steam-water mixture formed after heat exchange, and the separated steam-water mixture is discharged through the steam outlet (18).

8. The waste heat recovery exchanger of claim 1, wherein: The overall outer edge shape of the inner ring heat exchange pipe group (2) is hexagonal.

9. The waste heat recovery exchanger of claim 8, wherein: The overall inner edge shape and the overall outer edge shape of the outer ring heat exchange pipe group (3) are both hexagonal.

10. The waste heat recovery exchanger of claim 1, wherein: The inner ring heat exchange pipe group (2) and the outer ring heat exchange pipe group (3) are both composed of a plurality of U-shaped heat exchange pipes.

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