A waste heat recovery device and method for power plants

Abstract

This invention relates to the field of waste heat recovery technology, and more particularly to a waste heat recovery device and method for power plants. The waste heat recovery device for power plants includes: a tank, sealing plates, and heat exchange components; the tank includes a cylindrical body and end caps located at both ends of the cylindrical body; the sealing plates are disposed at both ends of the cylindrical body, and the two sealing plates and the cylindrical body form a heat exchange chamber, the sealing plates and the end caps forming a flue gas chamber; the heat exchange components are disposed within the heat exchange chamber, with both ends rotatably mounted on the sealing plates, including a first heat exchange component and a second heat exchange component, the first heat exchange component being nested within the second heat exchange component; gears are disposed on the sealing plates, and the rotation of the gears can drive the first and second heat exchange components to rotate in opposite directions. This invention allows fluids far from the heat exchange tubes to directly contact the heat exchange tubes, improving heat transfer efficiency and achieving full heat recovery.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a waste heat recovery device and method for power plants. Background Technology

[0002] During thermal power generation, a large amount of high-temperature flue gas is continuously generated. Direct emission of this gas would result in significant heat loss and reduce resource utilization. To address this issue, existing technologies have proposed various waste heat recovery devices to recover the heat from these high-temperature flue gases, achieving a good energy recovery objective.

[0003] The most common type of waste heat recovery device is the shell-and-tube heat exchanger. This heat exchange structure includes a waste heat inlet and outlet, and multiple heat exchange tubes are arranged inside. It also has a heat recovery fluid inlet and outlet. Heat exchange is formed through the contact of the tube walls, thereby obtaining the heat fluid that needs to be recovered.

[0004] However, in existing shell-and-tube structures, the flow of the heat recovery fluid inside the shell is relatively stable. This results in the near-fluid, which is in direct contact with the heat exchange tube, being able to exchange heat directly with the heat exchange tube, while the far-fluid, which cannot be in contact with the heat exchange tube, needs to exchange heat with the near-fluid. As a result, the heat transfer efficiency decreases, thus affecting the recovery and utilization of heat. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a power plant waste heat recovery device to improve the heat transfer efficiency of the waste heat recovery device.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A power plant waste heat recovery device includes: a tank, sealing plates, and heat exchange components; the tank includes a cylindrical body and end caps located at both ends of the cylindrical body; the sealing plates are disposed at both ends of the cylindrical body, the two sealing plates and the cylindrical body form a heat exchange chamber, and the sealing plates and the end caps form a flue gas chamber; the heat exchange components are disposed in the heat exchange chamber, and the two ends of the heat exchange components are rotatably mounted on the sealing plates, including a first heat exchange component and a second heat exchange component, the first heat exchange component being nested within the second heat exchange component; the sealing plates are provided with gears, and the rotation of the gears can drive the first heat exchange component and the second heat exchange component to rotate in opposite directions.

[0008] Preferably, the sealing plate includes an inner plate, an outer plate, and a connecting frame. The inner plate is fitted inside the outer plate, and the inner plate and the outer plate are connected by the connecting frame. The inner plate has a through hole in the middle. The first heat exchange component is rotatably installed in the through hole of the inner plate. There is an annular groove between the inner plate and the outer plate, and the second heat exchange component is rotatably installed in the annular groove.

[0009] Preferably, the connecting frame includes an inner ring, an outer ring, and a connecting rib. The inner ring and the outer ring are coaxially arranged, and the two ends of the connecting rib are respectively connected to the inner ring and the outer ring. The inner ring is detachably connected to the inner plate, and the outer ring is detachably connected to the outer plate.

[0010] Preferably, the through holes of the first heat exchange component and the inner plate are rotary sealed, and the second heat exchange component and the annular groove are rotary sealed.

[0011] Preferably, the first heat exchange assembly includes a first mounting base and a first heat exchange tube. There are two first mounting bases, and both ends of the first heat exchange tube are mounted on the two first mounting bases. The first mounting bases are rotatably connected to the through holes of the inner plate. The second heat exchange assembly includes a second mounting base and a second heat exchange tube. There are two second mounting bases, and both ends of the second heat exchange tube are mounted on the two second mounting bases. The second mounting bases are rotatably connected to the annular groove. One end of the gear meshes with the first heat exchange tube, and the other end meshes with the second heat exchange tube.

[0012] Preferably, the end caps at both ends are provided with a flue gas inlet and a flue gas outlet, and the cylinder is provided with a fluid inlet and a fluid outlet.

[0013] Preferably, the sealing plate is equipped with a drive motor for rotating the drive gear, and the drive motor is located inside the flue gas chamber with a flue gas outlet.

[0014] Preferably, the first heat exchange assembly includes a first heat exchange tube and a first mounting base, and the second heat exchange assembly includes a second heat exchange tube and a second mounting base. The second heat exchange tube has the same shape as the first heat exchange tube. The first heat exchange tube includes a straight tube section, a transition section, a spiral section, a transition section, and a straight tube section connected in sequence. The straight tube section of the first heat exchange tube is connected to the first mounting base.

[0015] This invention also provides a method for recovering waste heat from a power plant. The waste heat is recovered using the waste heat recovery device described above. Flue gas is introduced into the heat exchange chamber, and flue gas is introduced into the first heat exchange component and the second heat exchange component. The gear is rotated, which drives the first heat exchange component and the second heat exchange component to rotate in opposite directions, thus disturbing the fluid in the heat exchange chamber.

[0016] Preferably, the gear rotates in the opposite direction after a predetermined time.

[0017] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0018] This invention improves heat transfer efficiency and achieves full heat recovery by setting gears on the sealing plate. When the gears rotate, the two nested heat exchange components rotate in opposite directions, thereby disturbing the fluid in the heat exchange chamber. This allows the fluid far from the heat exchange tube to directly contact the heat exchange tube.

[0019] The heat exchange component of the recovery device of this invention rotates while exchanging heat, thus reducing scale formation. Furthermore, the gears on the sealing plate can reverse direction after a predetermined operating time, causing the heat exchange component to also reverse, which can remove some of the scale from the heat exchange tubes, further extending the scale formation time. Simultaneously, during descaling of the heat exchange tubes, the rotating heat exchange component can perform descaling more quickly, reducing downtime of the recovery device.

[0020] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram of the external appearance of the recycling device according to Embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the cylinder and sealing plate installation according to Embodiment 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the inside of the tank according to Embodiment 1 of the present invention;

[0026] Figure 4 This is a schematic diagram of the sealing plate according to Embodiment 1 of the present invention;

[0027] Figure 5 This is a cross-sectional view of the sealing plate according to Embodiment 1 of the present invention;

[0028] Figure 6 This is a schematic diagram of the first heat exchange component according to Embodiment 1 of the present invention;

[0029] Figure 7 This is a schematic diagram of the second heat exchange component according to Embodiment 1 of the present invention;

[0030] Figure 8 This is a half-sectional view of the second heat exchange component in Embodiment 1 of the present invention;

[0031] Figure 9 This is a schematic diagram of the heat exchange component and the sealing plate in Embodiment 1 of the present invention;

[0032] Figure 10 This is a schematic diagram of the gear and heat exchange tube assembly in Embodiment 1 of the present invention;

[0033] Figure 11 This is a schematic diagram of the first heat exchange component in Embodiment 2 of the present invention;

[0034] In the diagram: 1. Tank body; 11. Cylinder body; 111. Flue gas inlet; 112. Flue gas outlet; 12. End cap; 121. Flue gas inlet; 122. Flue gas outlet; 2. Sealing plate; 21. Connecting frame; 22. Inner plate; 23. Outer plate; 3. First heat exchange assembly; 31. First mounting base; 311. First baffle; 312. First mounting plate; 32. First heat exchange tube; 321. Straight pipe section; 322. Transition section; 323. Spiral section; 4. Second heat exchange assembly; 41. Second mounting base; 411. Second baffle; 412. Second mounting plate; 42. Second heat exchange tube; 51. Gear; 52. Drive motor;

[0035] The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only. Detailed Implementation

[0036] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] Terminology Explanation: The terms "installation," "connection," "linking," and "fixing" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to an internal connection between two components, or the interaction between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0039] Example 1:

[0040] As described in the background section, the flow of the heat recovery fluid within the shell in existing shell-and-tube structures is relatively stable, leading to a decrease in heat transfer efficiency and thus affecting heat recovery and utilization. To address the above technical problems, this invention proposes a power plant waste heat recovery device, such as... Figures 1-10 As shown, it includes: a tank body 1, sealing plates 2, and heat exchange components; the tank body 1 includes a cylindrical body 11 and end caps 12 located at both ends of the cylindrical body 11, the sealing plates 2 are disposed at both ends of the cylindrical body 11, the two sealing plates 2 and the cylindrical body 11 form a heat exchange chamber, and the sealing plates 2 and the end caps 12 form a flue gas chamber; the heat exchange components are disposed in the heat exchange chamber, and the two ends of the heat exchange components are rotatably mounted on the sealing plates 2, including a first heat exchange component 3 and a second heat exchange component 4, the first heat exchange component 3 being nested within the second heat exchange component 4; a gear 51 is disposed on the sealing plate 2, and the rotation of the gear 51 can drive the first heat exchange component 3 and the second heat exchange component 4 to rotate in opposite directions.

[0041] like Figure 1 As shown, the end caps 12 at both ends are respectively provided with a flue gas inlet 121 and a flue gas outlet 122, and the cylinder 11 is provided with a fluid inlet 111 and a fluid outlet 112, wherein the fluid can be water. Heat exchange is achieved between the fluid in the heat exchange chamber and the flue gas in the heat exchange components. This invention utilizes a gear 51 on the end cap 2, which causes the two nested heat exchange components to rotate in opposite directions when the gear 51 rotates, thereby disturbing the fluid in the heat exchange chamber. This allows the fluid far from the heat exchange tubes to directly contact the heat exchange tubes, improving heat transfer efficiency and achieving full heat recovery.

[0042] Meanwhile, in order to further improve heat exchange efficiency, multiple heat exchange components can be set in the heat exchange chamber, that is, a third heat exchange component, a fourth heat exchange component, etc. can be set outside the second heat exchange component 4. The third and fourth heat exchange components have the same structure as the second heat exchange component 4, only with a relatively larger diameter.

[0043] Furthermore, due to the hard water and high mineral content in some areas, scale will form on the outer wall of the heat exchange tubes after a period of use, further reducing heat exchange efficiency. The heat exchange components of the present invention rotate during heat exchange, thus reducing scale formation. On the other hand, the gear 51 on the sealing plate 2 can reverse direction after a predetermined operating time, causing the heat exchange components to also reverse. This reverses the force of the fluid relative to the heat exchange tubes, carrying away some of the scale and further prolonging the scale formation time. Simultaneously, when descaling the heat exchange tubes, descaling fluid is introduced into the heat exchange chamber. Rotating the heat exchange components at this time allows for faster descaling compared to a fixed heat exchange tube, reducing downtime of the recovery device.

[0044] like Figure 2 , Figure 4 , Figure 5 As shown, the sealing plate 2 includes an inner plate 22, an outer plate 23, and a connecting frame 21. The inner plate 22 is fitted inside the outer plate 23, and the inner plate 22 and the outer plate 23 are connected by the connecting frame 21. Specifically, the connecting frame 21 includes an inner ring, an outer ring, and a connecting rib. The inner ring and the outer ring are coaxially arranged, and the two ends of the connecting rib are respectively connected to the inner ring and the outer ring. The inner ring is detachably connected to the inner plate 22, and the outer ring is detachably connected to the outer plate 23. The inner plate 22 and the outer plate 23 are connected into a whole by the connecting frame 21. The detachable connection facilitates the installation of the second heat exchange assembly 4.

[0045] The inner plate 22 has a through hole in the middle, and the first heat exchange component 3 is rotatably installed in the through hole of the inner plate 22. An annular groove is formed between the inner plate 22 and the outer plate 23, and the second heat exchange component 4 is rotatably installed in the annular groove. Figure 3 , Figure 9 As shown, the through holes of the first heat exchange component 3 and the inner plate 22 are sealed by a rotary seal, and the second heat exchange component 4 and the annular groove are sealed by a rotary seal. The rotary seal can use existing structures, as long as it can ensure a seal while allowing the heat exchange component and the sealing plate 2 to rotate relative to each other. For example, the rotary seal can consist of a slip ring filled with polytetrafluoroethylene and a rubber O-ring providing elasticity. This rotary seal can be used to seal rods, shafts, pins, rotary joints, etc., that have rotating or oscillating motion.

[0046] like Figure 6As shown, the first heat exchange assembly 3 includes a first mounting base 31 and a first heat exchange tube 32. The first heat exchange tube 32 is a straight tube. There are two first mounting bases 31, and both ends of the first heat exchange tube 32 are mounted on the two first mounting bases 31. The first mounting bases 31 are rotatably connected to the through hole of the inner plate 22. Specifically, the first mounting base 31 includes a first baffle 311 and a first mounting plate 312. The first baffle 311 is snapped onto the back of the through hole of the inner plate 22, as shown. Figure 9 As shown. The first heat exchange tubes 32 are connected to the first mounting plate 312 in a circumferential array, and the ends of the first heat exchange tubes 32 are welded and fixed to the first mounting plate 312.

[0047] like Figure 7 As shown, the second heat exchange assembly 4 includes a second mounting base 41 and a second heat exchange tube 42. The second heat exchange tube 42 is a straight tube. There are two second mounting bases 41, and both ends of the second heat exchange tube 42 are mounted on the two second mounting bases 41. The second mounting bases 41 are rotatably connected to the annular groove. Figure 8 , Figure 9 As shown, the second mounting base 41 includes a second baffle 411 and a second mounting plate 412. The second baffle 411 is mounted on the back of the annular groove. The second heat exchange tubes 42 are connected to the second mounting plate 412 in a circumferential array. The ends of the second heat exchange tubes 42 are welded and fixed to the second mounting plate 412.

[0048] like Figure 10 As shown, one end of the gear 51 meshes with the first heat exchange tube 32, and the other end meshes with the second heat exchange tube 42. When the gear 51 rotates, the upper teeth of the gear 51 cause the first heat exchange tube 32 to rotate, and the lower teeth of the gear 51 cause the second heat exchange tube 42 to rotate in the opposite direction to the first heat exchange tube 32, thereby disturbing the fluid in the heat exchange chamber.

[0049] like Figure 9 As shown, a drive motor 52 for rotating a drive gear 51 is installed on the sealing plate 2. The drive motor 52 is located in the flue gas chamber with a flue gas outlet 122. Since the hot flue gas is transformed into low-temperature flue gas after heat exchange in the heat exchange chamber and discharged from the flue gas chamber with a flue gas outlet 122, placing the drive motor 52 in the flue gas chamber with a flue gas outlet 122 can provide a low-temperature environment for the drive motor 52 to ensure the normal operation of the drive motor 52.

[0050] Example 2:

[0051] The difference between this embodiment and embodiment one lies in the structure of the heat exchange tubes. In embodiment one, both the first heat exchange tube 32 and the second heat exchange tube 42 are straight tubes. In this embodiment, the second heat exchange tube 42 has the same shape as the first heat exchange tube 32, but the helical radius of the second heat exchange tube 42 is larger than that of the first heat exchange tube 32; for example... Figure 11 As shown, the first heat exchange tube 32 includes a straight tube section 321, a transition section 322, a spiral section 323, and a straight tube section 321 connected in sequence, wherein the spiral section 323 is the longest. The straight tube section 321 of the first heat exchange tube 32 is connected to the first mounting base 31. By setting the position near the first mounting base 31 as a straight tube section 321, it is convenient to mesh with the gear 51, thereby causing the first heat exchange assembly 3 to rotate under the drive of the gear 51. By setting the middle part of the first heat exchange tube 32 as a spiral shape, the length of the heat exchange tube is extended, the heat exchange area is increased, and the heat exchange efficiency is improved.

[0052] Furthermore, since the ends of the heat exchange tubes and the mounting base are fixed by welding, the expansion and contraction of the heat exchange tubes during thermal changes will cause stress at the weld joints, especially before and after maintenance shutdowns. Therefore, after prolonged use, leaks may occur at the weld joints. Therefore, this invention configures the heat exchange tubes in a spiral shape, and the end without gear 51 ( Figure 3 The mounting base at the left end of the tube can rotate freely relative to the sealing plate 2. When the heat exchange tube expands and contracts with heat, the longer spiral section 323 converts the thermal expansion into the relative rotation of the mounting bases at both ends. The relative rotation of the mounting base at the left end relative to the mounting base at the right end compensates for the thermal expansion of the heat exchange tube and avoids the problem of leakage at the weld.

[0053] Example 3:

[0054] Based on the power plant waste heat recovery device of Embodiment 1 or Embodiment 2, this Embodiment 3 proposes a power plant waste heat recovery method. Flue gas is introduced into the heat exchange chamber, and flue gas is introduced into the first heat exchange component 3 and the second heat exchange component 4. Rotating the gear 51 causes the first heat exchange component 3 and the second heat exchange component 4 to rotate in opposite directions, disturbing the fluid in the heat exchange chamber to improve heat exchange efficiency. Furthermore, the gear 51 rotates in the opposite direction after a predetermined time.

[0055] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A power plant waste heat recovery device, characterized in that, include: Tank body, sealing plates, and heat exchange components; The tank body includes a cylindrical body and end caps located at both ends of the cylindrical body; The sealing plates are disposed at both ends of the cylinder, and the two sealing plates and the cylinder form a heat exchange chamber, while the sealing plates and the end caps form a flue gas chamber. The heat exchange assembly is disposed in the heat exchange cavity, and both ends of the heat exchange assembly are rotatably mounted on the sealing plate. It includes a first heat exchange assembly and a second heat exchange assembly, with the first heat exchange assembly nested inside the second heat exchange assembly. The sealing plate is provided with gears, and the rotation of the gears can drive the first heat exchange assembly and the second heat exchange assembly to rotate in opposite directions. The first heat exchange assembly includes a first heat exchange tube and a first mounting base; the second heat exchange assembly includes a second heat exchange tube and a second mounting base; the second heat exchange tube has the same shape as the first heat exchange tube; the first heat exchange tube includes a straight tube section, a transition section, a spiral section, another transition section, and a straight tube section connected in sequence; the straight tube section of the first heat exchange tube is connected to the first mounting base. The mounting base at the end of the spiral heat exchange tube without the gear can rotate freely relative to the sealing plate.

2. The power plant waste heat recovery device as described in claim 1, characterized in that, The sealing plate includes an inner plate, an outer plate, and a connecting frame. The inner plate is fitted inside the outer plate, and the inner plate and the outer plate are connected by the connecting frame. The inner plate has a through hole in the middle. The first heat exchange component is rotatably installed in the through hole of the inner plate. There is an annular groove between the inner plate and the outer plate, and the second heat exchange component is rotatably installed in the annular groove.

3. The power plant waste heat recovery device as described in claim 2, characterized in that, The connecting frame includes an inner ring, an outer ring, and a connecting rib. The inner ring and the outer ring are coaxially arranged, and the two ends of the connecting rib are respectively connected to the inner ring and the outer ring. The inner ring is detachably connected to the inner plate, and the outer ring is detachably connected to the outer plate.

4. The power plant waste heat recovery device as described in claim 2, characterized in that, The first heat exchange component and the through hole of the inner plate are rotary sealed, and the second heat exchange component and the annular groove are rotary sealed.

5. The power plant waste heat recovery device as described in claim 2, characterized in that, The first heat exchange assembly includes a first mounting base and a first heat exchange tube. There are two first mounting bases, and both ends of the first heat exchange tube are mounted on the two first mounting bases. The first mounting bases are rotatably connected to the through holes of the inner plate. The second heat exchange assembly includes a second mounting base and a second heat exchange tube. There are two second mounting bases, and both ends of the second heat exchange tube are mounted on the two second mounting bases. The second mounting bases are rotatably connected to the annular groove. One end of the gear meshes with the first heat exchange tube, and the other end meshes with the second heat exchange tube.

6. The power plant waste heat recovery device as described in claim 1, characterized in that, The end caps at both ends are respectively provided with a flue gas inlet and a flue gas outlet, and the cylinder is provided with a fluid inlet and a fluid outlet.

7. The power plant waste heat recovery device as described in claim 6, characterized in that, The sealing plate is equipped with a drive motor that drives the gear to rotate, and the drive motor is located in the flue gas chamber with the flue gas outlet.

8. A method for recovering waste heat from a power plant, characterized in that, Waste heat is recovered using the power plant waste heat recovery device as described in any one of claims 1-7. Flue gas is introduced into the heat exchange chamber, and flue gas is introduced into the first heat exchange component and the second heat exchange component. The gear is rotated, and the gear drives the first heat exchange component and the second heat exchange component to rotate in opposite directions, thereby disturbing the fluid in the heat exchange chamber.

9. The power plant waste heat recovery method as described in claim 8, characterized in that, The gear rotates in the opposite direction after a predetermined time.

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