Device and method for reducing thermal stress of plate-fin heat exchanger based on graded heat exchange

Abstract

The invention belongs to the technical field of heat exchangers, and particularly relates to a device and method for reducing thermal stress of a plate-fin heat exchanger based on graded heat exchange, comprising a shell, a first pipeline interface, a second pipeline interface, a third pipeline interface, a fourth pipeline interface, a first distributor, a second distributor, a third distributor, a fourth distributor and heat exchange equipment; the heat exchange devices comprise the first heat exchange device, the second heat exchange device, the third heat exchange device, the fourth heat exchange device, the fifth heat exchange device and the sixth heat exchange device. And the first heat exchange equipment, the second heat exchange equipment and the third heat exchange equipment are sequentially arranged at intervals from top to bottom. The method is flexible in structural organization, high in adaptability and particularly suitable for cross-temperature-zone, high-pressure and frequent start and stop occasions, and the method is low in manufacturing cost and convenient to maintain and transport. The heat exchanger is subjected to graded anti-fatigue design, the failure rate of equipment is effectively reduced, the service life of the heat exchanger is prolonged, and the heat exchanger has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchangers, and in particular relates to a device and method for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange. Background Art

[0002] With the transformation of the global energy structure, liquid air energy storage systems have important research significance and broad application prospects due to their low cost and high energy density, as well as their characteristics of being unrestricted by geographical conditions and having high energy conversion efficiency. Plate-fin heat exchangers are used in liquid air energy storage systems as important heat exchange equipment due to their efficient heat exchange capacity. However, the actual operation process of heat exchangers in liquid energy storage systems is different from the past. They often face the challenges of cross-temperature zones, high pressure, and high thermal stress caused by frequent start-ups and shutdowns, which will cause alternating stress cycles inside the heat exchanger. With the action of long-term alternating stress, microcracks may gradually form at stress concentration points or material defect locations, seriously affecting the reliability and service life of the heat exchanger, and ultimately leading to fatigue failure of the heat exchanger, thus posing a serious threat to the safe operation of the system.

[0003] Traditional plate-fin heat exchangers typically utilize a monolithic structure. While simple to manufacture, they are highly susceptible to fatigue damage under alternating stresses, particularly during frequent start-stop operations. Existing plate-fin heat exchanger designs often address high stresses by increasing material thickness and using high-strength materials. However, these solutions often increase the manufacturing cost and volume of the heat exchanger and do not fundamentally address the thermal fatigue issue. Therefore, there is an urgent need for a design solution that can effectively improve the fatigue resistance of heat exchangers without significantly increasing their cost. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide a device and method for reducing the thermal stress of a plate-fin heat exchanger based on graded heat exchange. The plate-fin heat exchanger is designed with a graded structure, and the entire heat exchanger is divided into two or more independent working sections. Each working section can be regarded as a separate plate-fin heat exchanger. The working sections are connected in series or parallel, and insulation measures are applied to each working section and its connecting pipelines. By reducing the temperature difference between the internal fluid, the heat exchanger structure and the various fluids during startup, the thermal stress of the heat exchanger during startup is reduced, thereby solving the problem of frequent start and shutdown.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange, comprising a shell, a first pipe interface, a second pipe interface, a third pipe interface, a fourth pipe interface, a first distributor, a second distributor, a third distributor, a fourth distributor and a heat exchange device;

[0007] A first distributor, a second distributor, a third distributor, a fourth distributor and a plurality of heat exchange devices are respectively provided inside the shell; the plurality of heat exchange devices include a first heat exchange device, a second heat exchange device, a third heat exchange device, a fourth heat exchange device, a fifth heat exchange device and a sixth heat exchange device; the first heat exchange device, the second heat exchange device and the third heat exchange device are sequentially spaced from top to bottom, and the fourth heat exchange device, the fifth heat exchange device and the sixth heat exchange device are sequentially spaced from top to bottom;

[0008] The first heat exchange device and the fourth heat exchange device, the second heat exchange device and the fifth heat exchange device, and the third heat exchange device and the sixth heat exchange device are all connected through heat exchange device connecting pipelines, and automatic valves are provided on the heat exchange device connecting pipelines.

[0009] In actual applications, the volume and weight of each heat exchanger can vary, as can the heat exchange range. The diameter and thickness of the connecting pipes can also vary, and their specifications should be consistent with the connection ports of the heat exchanger they are connected to. Automatic valves are installed between the connecting pipes of each heat exchanger. When the heat exchanger is shut down, the automatic valves are closed; when the heat exchanger is started up, the automatic valves connected to the heat exchanger in use are opened.

[0010] Preferably, the third distributor and the fourth distributor are both arranged on the left side inside the shell, and the third distributor is respectively connected to the third pipe interface on the shell, and the first heat exchange device, the second heat exchange device and the third heat exchange device; the fourth distributor is respectively connected to the fourth pipe interface on the shell, and the first heat exchange device, the second heat exchange device and the third heat exchange device.

[0011] Preferably, the first distributor and the second distributor are both arranged on the right side inside the shell, and the first distributor is respectively connected to the first pipe interface on the shell, and the fourth heat exchange device, the fifth heat exchange device and the sixth heat exchange device; the second distributor is respectively connected to the second pipe interface on the shell, and the fourth heat exchange device, the fifth heat exchange device and the sixth heat exchange device.

[0012] Preferably, the first heat exchange device, the second heat exchange device, the third heat exchange device, the fourth heat exchange device, the fifth heat exchange device and the sixth heat exchange device are all provided with thermocouples, the purpose of which is to detect the temperature of each heat exchange device after shutdown. Each thermocouple is connected to a temperature display, and the temperature display is provided on the outside of the outer shell.

[0013] Preferably, thermal insulation filling materials are provided inside the shell, between the heat exchange devices, between the distributors, and between the connecting pipes of the heat exchange devices.

[0014] Preferably, the internal fluid material of the shell includes but is not limited to air; the first pipeline interface and the third pipeline interface are the first flow inlet and outlet of the device, and the second pipeline interface and the fourth pipeline interface are the second flow inlet and outlet of the device.

[0015] The present invention also provides a method for using a device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange, comprising:

[0016] When the heat exchanger is started for heat exchange, the first fluid pipeline must be connected to the first pipeline interface, the second fluid pipeline must be connected to the fourth pipeline interface, and the automatic valve must be opened; the first fluid flows into the first pipeline interface, flows through the first distributor into the fourth heat exchange device, the fifth heat exchange device, and the sixth heat exchange device, exchanges heat with the second fluid, and then is combined through the third distributor and discharged from the third pipeline interface; the second fluid flows into the fourth pipeline interface, flows through the fourth distributor into the first heat exchange device, the second heat exchange device, and the third heat exchange device, exchanges heat with the first fluid, and then is combined through the second distributor and discharged from the second pipeline interface;

[0017] When the heat exchanger is shut down, the automatic valve needs to be closed. At this time, the heat exchange devices in the heat exchanger are disconnected and reach their respective uniform temperature states over time.

[0018] By adopting the above technical solution: the heat exchanger adopts a hierarchical structure design, the overall heat exchanger is divided into two or more independent working sections, and the working sections are connected in series or parallel. Insulation measures are applied to each working section and its connecting pipelines. By reducing the temperature difference between the internal fluid, the heat exchanger structure and the various fluid streams during startup, the thermal stress of the heat exchanger is reduced, thereby solving the problem of frequent start and stop.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention reduces the thermal stress and improves fatigue resistance by reducing the temperature difference inside the heat exchanger when starting up.

[0021] 2. The present invention adopts a hierarchical design approach, which enables the heat exchanger to adapt to different working environments and is suitable for extreme working conditions such as high temperature difference and pressure.

[0022] 3. The present invention adopts a hierarchical design approach, which has a flexible structure, low manufacturing cost, and is convenient for transportation and maintenance.

[0023] 4. The present invention adopts a hierarchical design method, which is flexible in operation, has a large adjustment space, and is suitable for working conditions with a large span. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the connection between the heat exchange device and the automatic valve in the present invention;

[0026] Figure 3 This is a side view of the connection between the heat exchange device and the automatic valve in the present invention;

[0027] Figure 4 This is a flange connection diagram of the pipeline interface and the distributor in the present invention;

[0028] Figure 5 It is an enlarged schematic diagram of the temperature display and thermocouple installation in the present invention.

[0029] Reference numerals:

[0030] 1-shell, 2-first pipeline interface, 3-second pipeline interface, 4-third pipeline interface, 5-fourth pipeline interface, 6-first distributor, 7-second distributor, 8-third distributor, 9-fourth distributor, 10-thermal insulation filling material, 11-heat exchange equipment connecting pipeline, 12-1-first heat exchange equipment, 12-2-second heat exchange equipment, 12-3-third heat exchange equipment, 12-4-fourth heat exchange equipment, 12-5-fifth heat exchange equipment, 12-6-fifth heat exchange equipment, 13-automatic valve, 14-temperature display, 15-thermocouple. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] A device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange, comprising a housing 1, a first pipe interface 2, a second pipe interface 3, a third pipe interface 4, a fourth pipe interface 5, a first distributor 6, a second distributor 7, a third distributor 8, a fourth distributor 9 and a heat exchange device;

[0034] The shell 1 is provided with a first distributor 6, a second distributor 7, a third distributor 8, a fourth distributor 9 and a plurality of heat exchange devices respectively; the plurality of heat exchange devices include a first heat exchange device 12-1, a second heat exchange device 12-2, a third heat exchange device 12-3, a fourth heat exchange device 12-4, a fifth heat exchange device 12-5 and a sixth heat exchange device 12-6; the first heat exchange device 12-1, the second heat exchange device 12-2 and the third heat exchange device 12-3 are arranged in sequence from top to bottom, and the fourth heat exchange device 12-4, the fifth heat exchange device 12-5 and the sixth heat exchange device 12-6 are arranged in sequence from top to bottom;

[0035] The first heat exchanger 12-1 and the fourth heat exchanger 12-4, the second heat exchanger 12-2 and the fifth heat exchanger 12-5, and the third heat exchanger 12-3 and the sixth heat exchanger 12-6 are all connected through a heat exchanger connecting pipeline 11, and an automatic valve 13 is provided on the heat exchanger connecting pipeline 11.

[0036] In actual application, each distributor and each pipeline interface is flange-connected, the volume and weight of each heat exchanger can be different, and the heat exchange range of each heat exchanger can be different; the diameter and thickness of the connecting pipeline of each heat exchanger can be different, and its specifications should be consistent with the connecting port of the heat exchanger to which it is connected. By providing an automatic valve 13 between the connecting pipelines of each heat exchanger, when the heat exchanger is shut down, the automatic valve 13 is closed; when the heat exchanger is started, the automatic valve connected to the part of the heat exchanger in use is opened. The purpose here is to close the automatic valve when the heat exchanger is shut down, so that the heat exchangers on both sides have different average temperatures, narrow the temperature difference between the cold and hot fluids and the heat exchanger structure and the internal fluid temperature of the heat exchanger when starting up, reduce thermal stress, and improve fatigue resistance.

[0037] In addition, in actual application, the heat exchange equipment can be multi-level, not limited to Figure 1 Classification: Classified heat exchange equipment can be used in series and parallel, not limited to Figure 1 When in use, according to project needs, when the actual outlet temperature of the heat exchange equipment cannot meet the ideal demand, the outlet temperature can be adjusted by adding a series heat exchanger; when the heat exchange equipment has a large demand for flow, the required flow can be adapted by adding a parallel heat exchanger.

[0038] It should be noted that grading should be avoided as much as possible in the phase change section of the plate-fin heat exchanger, and grading should be avoided as much as possible in areas with large temperature differences within the same cross-section of the plate-fin heat exchanger. Grading should take economic efficiency into consideration and should not be blindly graded.

[0039] Specifically, the third distributor 8 and the fourth distributor 9 are both arranged on the left side of the shell 1, and the third distributor 8 is respectively connected to the third pipe interface 4 on the shell 1, and the first heat exchange device 12-1, the second heat exchange device 12-2 and the third heat exchange device 12-3; the fourth distributor 9 is respectively connected to the fourth pipe interface 5 on the shell 1, and the first heat exchange device 12-1, the second heat exchange device 12-2 and the third heat exchange device 12-3.

[0040] Specifically, the first distributor 6 and the second distributor 7 are both arranged on the right side inside the outer shell 1, and the first distributor 6 is respectively connected to the first pipe interface 2 on the outer shell 1, and the fourth heat exchange device 12-4, the fifth heat exchange device 12-5 and the sixth heat exchange device 12-6; the second distributor 7 is respectively connected to the second pipe interface 3 on the outer shell 1, and the fourth heat exchange device 12-4, the fifth heat exchange device 12-5 and the sixth heat exchange device 12-6.

[0041] Specifically, the first heat exchange device 12-1, the second heat exchange device 12-2, the third heat exchange device 12-3, the fourth heat exchange device 12-4, the fifth heat exchange device 12-5 and the sixth heat exchange device 12-6 are all provided with thermocouples 15, the purpose of which is to detect the temperature of each heat exchange device after shutdown. Each thermocouple 15 is connected to a temperature display 14, and the temperature display 14 is provided on the outside of the outer casing 1.

[0042] Specifically, thermal insulation filling materials 10 are provided inside the shell 1, between each heat exchange device, between each distributor, and between each heat exchange device connecting pipeline.

[0043] Specifically, the internal fluid material of the shell 1 includes but is not limited to air; the first pipeline interface 2 and the third pipeline interface 4 are the first flow inlet and outlet of the device, and the second pipeline interface 3 and the fourth pipeline interface 5 are the second flow inlet and outlet of the device.

[0044] A method for using a device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange, comprising:

[0045] When the heat exchanger is started for heat exchange, the first fluid pipeline must first be connected to the first pipeline interface 2, the second fluid pipeline must be connected to the fourth pipeline interface 5, and the automatic valve 13 must be opened; the first fluid flows into the first pipeline interface 2, flows through the first distributor 6 into the fourth heat exchange device 12-4, the fifth heat exchange device 12-5, and the sixth heat exchange device 12-6, exchanges heat with the second fluid, and then is combined through the third distributor 8 and discharged from the third pipeline interface 4; the second fluid flows into the fourth pipeline interface 5, flows through the fourth distributor 9 into the first heat exchange device 12-1, the second heat exchange device 12-2, and the third heat exchange device 12-3, exchanges heat with the first fluid, and then is combined through the second distributor 7 and discharged from the second pipeline interface 3;

[0046] When the heat exchanger is shut down, the automatic valve 13 needs to be closed. At this time, the heat exchange devices in the heat exchanger are disconnected and reach their respective uniform temperature states over time.

[0047] In summary, the present invention boasts a flexible structure and strong adaptability, making it particularly suitable for applications involving cross-temperature ranges, high pressures, and frequent starts and stops. Furthermore, this method offers low manufacturing costs and facilitates maintenance and transportation. By implementing a graded anti-fatigue design for the heat exchanger, the present invention effectively reduces equipment failure rates and extends its service life, demonstrating its broad potential for application.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange, characterized in that: The heat exchange device comprises a housing (1), a first pipeline interface (2), a second pipeline interface (3), a third pipeline interface (4), a fourth pipeline interface (5), a first distributor (6), a second distributor (7), a third distributor (8), a fourth distributor (9), and a heat exchange device; The shell (1) is provided with a first distributor (6), a second distributor (7), a third distributor (8), a fourth distributor (9) and a plurality of heat exchange devices; the plurality of heat exchange devices include a first heat exchange device (12-1), a second heat exchange device (12-2), a third heat exchange device (12-3), a fourth heat exchange device (12-4), a fifth heat exchange device (12-5) and a sixth heat exchange device (12-6); the first heat exchange device (12-1), the second heat exchange device (12-2) and the third heat exchange device (12-3) are arranged in sequence from top to bottom, and the fourth heat exchange device (12-4), the fifth heat exchange device (12-5) and the sixth heat exchange device (12-6) are arranged in sequence from top to bottom; The first heat exchange device (12-1) and the fourth heat exchange device (12-4), the second heat exchange device (12-2) and the fifth heat exchange device (12-5), and the third heat exchange device (12-3) and the sixth heat exchange device (12-6) are all connected via a heat exchange device connecting pipeline (11), and an automatic valve (13) is provided on the heat exchange device connecting pipeline (11).

2. The device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to claim 1, characterized in that: The third distributor (8) and the fourth distributor (9) are both arranged on the left side of the interior of the shell (1); the third distributor (8) is respectively connected to the third pipe interface (4) on the shell (1), and the first heat exchange device (12-1), the second heat exchange device (12-2), and the third heat exchange device (12-3); the fourth distributor (9) is respectively connected to the fourth pipe interface (5) on the shell (1), and the first heat exchange device (12-1), the second heat exchange device (12-2), and the third heat exchange device (12-3).

3. The device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to claim 2, characterized in that: The first distributor (6) and the second distributor (7) are both arranged on the right side of the interior of the shell (1); the first distributor (6) is respectively connected to the first pipe interface (2) on the shell (1), and the fourth heat exchange device (12-4), the fifth heat exchange device (12-5), and the sixth heat exchange device (12-6); the second distributor (7) is respectively connected to the second pipe interface (3) on the shell (1), and the fourth heat exchange device (12-4), the fifth heat exchange device (12-5), and the sixth heat exchange device (12-6).

4. The device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to claim 1, characterized in that: The first heat exchange device (12-1), the second heat exchange device (12-2), the third heat exchange device (12-3), the fourth heat exchange device (12-4), the fifth heat exchange device (12-5), and the sixth heat exchange device (12-6) are all provided with thermocouples (15), each thermocouple (15) is connected to a temperature display (14), and the temperature display (14) is provided on the outside of the housing (1).

5. The device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to claim 1, characterized in that: Thermal insulation filling materials (10) are provided inside the shell (1), between the heat exchange devices, between the distributors, and between the connecting pipes of the heat exchange devices.

6. The device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to claim 1, characterized in that: The internal fluid material of the housing (1) includes air; the first pipeline interface (2) and the third pipeline interface (4) are the first flow inlet and outlet of the device, and the second pipeline interface (3) and the fourth pipeline interface (5) are the second flow inlet and outlet of the device.

7. A method for using a device for reducing thermal stress of a plate-fin heat exchanger based on staged heat exchange according to any one of claims 1 to 6, characterized in that: include: When the heat exchanger is started for heat exchange, the first fluid pipeline must be connected to the first pipeline interface (2), the second fluid pipeline must be connected to the fourth pipeline interface (5), and the automatic valve (13) must be opened; the first fluid flows into the first pipeline interface (2), flows through the first distributor (6) into the fourth heat exchange device (12-4), the fifth heat exchange device (12-5) and the sixth heat exchange device (12-6), exchanges heat with the second fluid, and then flows through the third distributor (8) and is discharged from the third pipeline interface (4); the second fluid flows into the fourth pipeline interface (5), flows through the fourth distributor (9) into the first heat exchange device (12-1), the second heat exchange device (12-2) and the third heat exchange device (12-3), exchanges heat with the first fluid, and then flows through the second distributor (7) and is discharged from the second pipeline interface (3); When the heat exchanger is shut down, the automatic valve (13) needs to be closed. At this time, the heat exchange devices in the heat exchanger are disconnected and reach their respective uniform temperature states over time.

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