Self-cleaning soot flue gas waste heat exchange device

Abstract

This invention provides a self-cleaning flue gas waste heat exchange device, comprising a first flow guide member disposed within the housing near the inlet of the hot fluid, and a second flow guide member disposed within the housing near the outlet of the hot fluid. The first flow guide member includes uniformly and vertically arranged first blades, all of which are connected together by a first connecting rod. A vertical first rotating shaft is connected to the middle of the first connecting rod, and the first rotating shaft is connected to a first rotating motor. The second flow guide member includes uniformly and vertically arranged second blades, all of which are connected together by a second connecting rod. A vertical second rotating shaft is connected to the middle of the second connecting rod, and the second rotating shaft is connected to a second rotating motor. This invention can change the flow direction of the hot fluid, reduce ash accumulation on the heat exchange tube assembly, and improve heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of waste heat, waste energy recovery and efficient utilization technology, and more specifically, to a self-cleaning flue gas waste heat exchange device. Background Technology

[0002] With the increasing severity of the energy crisis and ever-increasing environmental protection requirements, waste heat recovery technology has gradually become a new approach to energy conservation and emission reduction. Waste heat refers to the heat generated during industrial production processes that is not fully utilized. By recovering this waste heat, it can be converted into useful energy, achieving efficient energy utilization and reducing energy consumption.

[0003] Among recoverable waste heat resources, flue gas waste heat accounts for a significant proportion. Effective utilization of flue gas waste heat can substantially reduce primary energy consumption and improve energy efficiency. However, industrial flue gas waste heat often contains a certain concentration of fly ash particles, causing ash accumulation on the heat exchanger tubes when the flue gas enters the heat exchanger. Ash accumulation on the heating surfaces not only increases thermal resistance and decreases the convective heat transfer coefficient, reducing heat transfer capacity, but also affects the stable operation of the system. Blast furnace gas is a byproduct of coke combustion and iron ore reduction reactions during blast furnace ironmaking. Its main components are CO, CO2, H2, and N2, and it is a usable low-calorific-value combustible gas. Currently, in blast furnace gas combustion power generation projects, boiler flue gas, after passing through a gas heater and desulfurization and dust removal, is sent to the chimney by an induced draft fan for discharge. The exhaust temperature is 130℃-140℃, and this portion of heat accounts for approximately 3.6% of the total heat in the entire flue gas process.

[0004] Heat pipe heat exchangers are highly efficient heat transfer devices widely used in waste heat recovery, electronic cooling, aerospace, and other fields. However, despite their many advantages, existing heat pipe heat exchanger technology still has some drawbacks and limitations. The main drawbacks of low-temperature flue gas heat pipe heat exchangers are ash accumulation and corrosion, which reduce heat transfer efficiency and service life. Solving the ash accumulation problem usually requires additional equipment. For example, steam soot blowers use high-pressure steam jets to impact the heat exchange surface and remove ash, but this is energy-intensive and may cause pipe wall corrosion or thermal stress problems. Acoustic soot blowers use the vibration energy of sound waves or infrasound to loosen and remove ash from the surface, but their effectiveness is limited for sticky ash or hard deposits. Other options include gas pulse soot blowers and compressed air soot blowers, all of which increase costs. Utility Model Content

[0005] In view of the above problems, the purpose of this utility model is to provide a self-cleaning flue gas waste heat exchange device, which has a flow guide that can change the flow direction of the hot fluid, so as to avoid the flue gas flow direction always being fixed, reduce the formation of ash on the heat exchange tube assembly, and improve the heat exchange efficiency.

[0006] This utility model provides a self-cleaning flue gas waste heat exchange device, including a shell and a heat exchange tube assembly disposed in the shell. The hot fluid inlet and hot fluid outlet of the shell are located at the left and right ends of the shell, respectively.

[0007] A first flow guide is disposed inside the housing near the hot fluid inlet, and a second flow guide is disposed inside the housing near the hot fluid outlet.

[0008] The first guide member includes vertical first blades evenly arranged along the side of the heat exchange tube assembly facing the hot fluid inlet. The edges of all the first blades facing the hot fluid inlet are connected together by a first connecting rod. A vertical first rotating shaft is connected to the middle of the first connecting rod. The first rotating shaft passes through the housing and is connected to a first rotating motor.

[0009] The second guide includes vertical second blades evenly arranged along the side of the heat exchange tube assembly toward the hot fluid outlet. The edges of all the second blades toward the hot fluid outlet are connected together by a second connecting rod. A vertical second rotating shaft is connected to the middle of the second connecting rod. The second rotating shaft passes through the housing and is connected to a second rotating motor.

[0010] The first blade and the second blade have the same shape and size.

[0011] The first blade includes a trapezoidal plate and a rectangular plate connected to the long base of the trapezoidal plate. The length of the rectangular plate is the same as the long base of the trapezoidal plate. The rectangular plate and the trapezoidal plate are on the same plane. The short base of the trapezoidal plate is perpendicularly connected to the first connecting rod.

[0012] The length of the rectangular plate is adapted to the inner height of the shell.

[0013] The spacing between adjacent first blades is the same as the spacing between adjacent second blades.

[0014] The number of both the first connecting rod and the second connecting rod is at least two.

[0015] The lengths of both the first connecting rod and the second connecting rod are less than the width of the housing.

[0016] Both ends of the first rotating shaft extend out of the housing and are rotatably connected to the housing via a first sealing ring; both ends of the second rotating shaft extend out of the housing and are rotatably connected to the housing via a second sealing ring.

[0017] Both the first sealing ring and the second sealing ring are sealed bearings.

[0018] The lower ends of the first rotating shaft and the second rotating shaft are respectively connected to the rotating shafts of the first rotating motor and the second rotating motor.

[0019] As described above, the self-cleaning flue gas waste heat exchange device provided by this invention has a first guide member installed near the hot fluid inlet inside the shell, and a second guide member installed near the hot fluid outlet inside the shell. The blades of both the first and second guide members are rotatable, changing the flow direction and path of the fluid within the shell. This prevents flue gas from being blown towards a fixed position on the heat exchange tubes for extended periods, reducing ash accumulation on the heat exchange tube assembly. The multi-directional blowing also removes existing ash buildup. This invention can automatically reduce and clean ash accumulation on the heat exchange tubes, while simultaneously improving heat exchange efficiency, reducing low-temperature corrosion, and extending equipment lifespan. Attached Figure Description

[0020] Other objects and results of this invention will become more apparent and readily understood upon referring to the following description taken in conjunction with the accompanying drawings, and with a more complete understanding of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of the self-cleaning flue gas waste heat exchange device according to Embodiment 1 of this utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the first flow guide according to Embodiment 1 of the present invention;

[0023] Figure 3 for Figure 1 AA section view;

[0024] Figure 4 This is a schematic diagram of the flow path of the self-cleaning flue gas waste heat exchange device according to Embodiment 2 of this utility model;

[0025] Figure 5 This is a schematic diagram of the flow path of the self-cleaning flue gas waste heat exchange device according to Embodiment 3 of this utility model;

[0026] Among them, 1-first guide component, 11-first blade, 111-trapezoidal plate, 112-rectangular plate, 12-first connecting rod, 13-first rotating shaft, 14-first rotating motor, 2-second guide component, 21-second blade, 22-second connecting rod, 23-second rotating shaft, 24-second rotating motor, 3-first sealing ring, 4-second sealing ring, 5-heat exchanger tube assembly, 6-shell, 7-hot fluid inlet, 8-hot fluid outlet;

[0027] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0028] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for ease of description of one or more embodiments.

[0029] This invention can be modified in various ways and has various embodiments, with specific embodiments illustrated in the accompanying drawings. However, this invention is not limited to this specific implementation and all modifications, equivalents, and substitutions falling within the spirit and technical scope of this invention are to be understood as included.

[0030] Ordinal terms such as "first," "second," etc., may be used to describe various constituent elements, but the constituent elements are not limited to these terms. The terms are used only to distinguish one constituent element from another. For example, without departing from the scope of the claims of this utility model, a second constituent element may be named a first constituent element, and similarly, a first constituent element may be named a second constituent element. Terms and / or include combinations of multiple associated items or one of multiple associated items.

[0031] It should be understood that when referring to a constituent element being "connected" or "in contact" with other constituent elements, this includes not only cases where it is directly connected or in contact with other constituent elements, but also cases where other constituent elements exist between them. Conversely, when referring to a constituent element being "directly connected" or "directly in contact" with other constituent elements, it should be understood that no other constituent elements exist between them.

[0032] In the description of the embodiments, when it is stated that a certain component is formed "on or under" other components, "on or under" includes both two components that are in direct contact with each other and at least one other component that is configured to be formed between the two components. Furthermore, when expressed as "on or under", based on a certain component, it refers not only to the upper direction but may also include the lower direction.

[0033] The terminology used in this application is for illustrative purposes only and is not intended to limit the scope of the invention. Unless the context clearly specifies otherwise, singular expressions include plural expressions. In this application, terms such as "comprising" or "having" are used to specify the presence of features, numbers, steps, operations, constituent elements, components, or combinations thereof described in the specification, and do not preclude the presence or additional possibilities of one or more other features, numbers, steps, operations, constituent elements, components, or combinations thereof.

[0034] Unless otherwise defined, including technical or scientific terms, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Terms as defined in commonly used dictionaries should be interpreted in a meaning consistent with their meaning in the context of the relevant art, and should not be construed as having an ideal or overly formal meaning unless explicitly defined in this application.

[0035] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0036] Example 1

[0037] like Figures 1-3 As shown in the figure, the self-cleaning flue gas waste heat exchange device proposed in this embodiment can be used for the recovery and utilization of waste heat from industrial flue gas, as well as for the recovery and utilization of waste heat from other gases containing particulate matter.

[0038] The existing flue gas waste heat exchange device includes a shell 6 and a heat exchange tube assembly 5 disposed within the shell 6. The hot fluid inlet 7 and hot fluid outlet 8 of the shell 6 are located at the left and right ends of the shell 6, respectively. During normal heat exchange, when the airflow passes through the heat exchange tube assembly 5, vortices or low-velocity zones are formed behind the tube wall, especially on the leeward side of the tube, where particulate matter in the airflow easily deposits and accumulates. Ash accumulation negatively impacts the performance, operating efficiency, and lifespan of the heat exchange tubes. Ash forms a heat insulation layer on the surface of the heat exchange tubes, increasing thermal resistance and reducing heat transfer efficiency. Due to the reduced heat transfer efficiency, the overall heat exchange capacity of the heat exchange tube assembly 5 decreases, leading to increased system energy consumption. Furthermore, certain components in the ash (such as sulfates and chlorides) may absorb moisture, forming a corrosive medium that causes corrosion on the surface of the heat exchange tubes, shortening the equipment's service life.

[0039] This self-cleaning flue gas waste heat exchanger is an improvement on the existing flue gas waste heat exchanger. A first guide element 1 and a second guide element 2 are added to the windward and leeward sides of the heat exchange tube assembly 5, respectively. The guiding direction of the first guide element 1 and the second guide element 2 can be changed according to the ash accumulation or at regular intervals to alter the flow direction and velocity of the flue gas. Changing the flow direction prevents particulate matter from always drifting to a fixed position on the heat exchange tubes, while the change in velocity increases the turbulence intensity of the flue gas, improving the suspension capacity of the particulate matter and making it less prone to deposition. The high-speed flow phase can also flush away some of the deposited dust.

[0040] Existing flue gas waste heat exchangers have an upper shell above the outer shell 6. The upper part of each heat exchange tube in the heat exchange tube assembly 5 is inserted into the upper shell, transferring the heat obtained from absorbing waste heat to the fluid in the upper shell, thus recovering and utilizing the waste heat from the flue gas. This self-cleaning flue gas waste heat exchanger eliminates the need for an additional soot blower, automatically eliminating ash accumulation on the heat exchange tubes, keeping the heat exchange tubes clean, improving the efficiency of flue gas waste heat recovery, and protecting the equipment.

[0041] A first guide element 1 is provided inside the shell 6 near the hot fluid inlet 7, and a second guide element 2 is provided inside the shell 6 near the hot fluid outlet 8. The first guide element 1 and the second guide element 2 are respectively located at the inlet and outlet of the flue gas flow, and cooperate with each other to change the flue gas flow path and speed.

[0042] In order to effectively guide the flue gas, the first guide member 1 and the second guide member 2 can have the same structure and be arranged opposite to each other.

[0043] The first guide element 1 may include vertical first blades 11 uniformly arranged along the side of the heat exchange tube assembly 5 toward the hot fluid inlet 7. The edges of all the first blades 11 toward the hot fluid inlet 7 are connected together by a first connecting rod 12. A vertical first rotating shaft 13 is connected to the middle of the first connecting rod 12. The first rotating shaft 13 extends out of the housing 6 and is connected to the first rotating motor 14.

[0044] The heat exchanger tube assembly 5 includes several vertically arranged pipes that almost cover the width of the shell 6. The first blades 11 of the first guide member 1 are evenly spaced along the width of the shell 6. The spacing can be determined according to specific conditions such as flue gas velocity and pipe density. The height of the first blades 11 is slightly less than the height of the shell 6, so as to guide the flow upwards to the entire heat exchanger tube assembly 5. All the first blades 11 are connected as a whole, and the first blades 11 face the heat exchanger tube assembly 5. When the flue gas enters, it is guided along the first blades 11.

[0045] To adjust the flow direction of the first blade 11, the first flow guide 1 is driven to rotate by the first rotating motor 14. The shaft of the first rotating motor 14 is connected to the first connecting rod 12 in the middle of the first flow guide 1, causing the first flow guide 1 to rotate about the vertical centerline. The first blade 11 is perpendicular to the first connecting rod 12, and several first blades 11 are arranged side by side along the first connecting rod 12. When the first rotating motor 14 returns to its original position, the first connecting rod 12 is along the width direction of the housing 6, and the first blades 11 are all facing the heat exchange tube assembly 5, so the incoming flue gas flows perpendicularly towards the heat exchange tube assembly 5; when the first rotating motor 14 is rotated, the angle between the first connecting rod 12 and the width direction of the housing 6 can be adjusted, so the first blades 11 are all tilted towards the heat exchange tube assembly 5, so the incoming flue gas flows obliquely towards the heat exchange tube assembly 5.

[0046] The first rotating motor 14 is located outside the housing 6, making it easy to control.

[0047] The second guide member 2 may include vertical second blades 21 uniformly arranged along the side of the heat exchange tube assembly 5 toward the hot fluid outlet 8. The edges of all the second blades 21 toward the hot fluid outlet 8 are connected together by a second connecting rod 22. A vertical second rotating shaft 23 is connected to the middle of the second connecting rod 22. The second rotating shaft 23 extends out of the housing 6 and is connected to the second rotating motor 24.

[0048] The second blades 21 of the second guide member 2 are evenly spaced along the width direction of the housing 6, and the spacing can be the same as the spacing between the first blades 11. The height of the second blades 21 is slightly less than the height of the housing 6. The second blades 21 and the first blades 11 cooperate to guide the flue gas into different flow directions. All the second blades 21 are connected as a whole, and the second blades 21 face the heat exchange tube assembly 5. When the flue gas flows out of the housing 6 along the second blades 21...

[0049] To adjust the flow direction of the second blade 21, the second flow guide 2 is driven to rotate by the second rotating motor 24. The shaft of the second rotating motor 24 is connected to the second connecting rod 22 in the middle of the second flow guide 2, causing the second flow guide 2 to rotate about the vertical centerline. The second blade 21 is perpendicular to the second connecting rod 22, and several second blades 21 form a parallel arrangement along the second connecting rod 22. When the second rotating motor 24 returns to its original position, the second connecting rod 22 is along the width direction of the housing 6, and the second blades 21 are all facing the heat exchange tube assembly 5, with the flue gas flowing out perpendicular to the heat exchange tube assembly 5. When the second rotating motor 24 is rotated, the angle between the second connecting rod 22 and the width direction of the housing 6 can be adjusted, and the second blades 21 are all tilted towards the heat exchange tube assembly 5, with the flue gas flowing out at an angle.

[0050] The second rotating motor 24 is located outside the housing 6, making it easy to control.

[0051] In one specific embodiment of this utility model, in order to achieve a good cooperation between the first flow guide 1 and the second flow guide 2, the first blade 11 and the second blade 21 are of the same shape and size. The first blade 11 and the second blade 21 of the same shape can cooperate better to guide the flow and achieve the required flow direction and velocity.

[0052] In one specific embodiment of this utility model, for ease of airflow guidance, the first blade 11 includes an isosceles trapezoidal plate 111 and a rectangular plate 112 connected to the long base of the trapezoidal plate 111. The length of the rectangular plate 112 is equal to the long base of the trapezoidal plate 111. The rectangular plate 112 and the trapezoidal plate 111 are on the same plane. The short base of the trapezoidal plate 111 is perpendicularly connected to the first connecting rod 12, and the short base of the trapezoidal plate 111 is slightly shorter than the long base. The blade is basically rectangular, which facilitates the guidance of flue gas in the housing 6. Both the first blade 11 and the second blade 21 are made of heat-resistant and corrosion-resistant materials.

[0053] In one specific embodiment of this utility model, in order to guide the flue gas comprehensively, the length of the rectangular plate 112 is adapted to the inner height of the shell 6. The length of the rectangular plate 112 is almost the same as the inner height of the shell 6 and not less than the height of the heat exchange tube assembly 5, which can more effectively guide the flue gas diffused into the shell 6 and prevent the flue gas from depositing at any position of the heat exchange tube assembly 5.

[0054] In one specific embodiment of this utility model, in order to guide the flow more smoothly, the spacing between adjacent first blades 11 is the same as the spacing between adjacent second blades 21, and the arrangement of all first blades 11 and all second blades 21 is the same.

[0055] like Figure 1 As shown, when the first rotating motor 14 and the second rotating motor 24 return to their original positions, all the first blades 11 and all the second blades 21 are symmetrically arranged. In this state, the flue gas has low running resistance and flows in a straight line, forming a vortex and a low-speed zone directly behind the heat exchanger tube assembly 5. This state is one type of flow guidance. Several other flow guidance methods operate alternately with this flow guidance method, which can prevent particulate matter in the flue gas from adhering to the heat exchanger tube assembly 5.

[0056] In one specific embodiment of this utility model, the number of first connecting rods 12 and second connecting rods 22 is at least two. A first connecting rod 12 can be connected to the upper and lower ends of the back edge of each of the first blades 11, and a first connecting rod 12 can be connected to the upper and lower ends of the back edge of each of the second blades 21. The first connecting rods 12 and second connecting rods 22 can securely connect all the first blades 11 and second blades 21.

[0057] In one specific embodiment of this utility model, in order for the first guide member 1 and the second guide member 2 to rotate smoothly within the housing 6, the lengths of both the first connecting rod 12 and the second connecting rod 22 are less than the width of the housing 6. The lengths of the first connecting rod 12 and the second connecting rod 22 must be sufficient to allow free rotation in the width direction of the housing 6 while also connecting all the blades.

[0058] In one specific embodiment of this utility model, for stable vertical rotation of the shafts, both ends of the first shaft 13 extend through the housing 6 and are rotatably connected to the housing 6 via a first sealing ring 3. Both ends of the second shaft 23 extend through the housing 6 and are rotatably connected to the housing 6 via a second sealing ring 4. Both ends of the first shaft 13 / second shaft 23 are limited by the housing 6, allowing for stable vertical rotation. The first shaft 13 / second shaft 23 are sealed to the housing 6 using the first sealing ring 3 / second sealing ring 4, preventing flue gas leakage.

[0059] In one specific embodiment of this utility model, both the first sealing ring 3 and the second sealing ring 4 can be sealed bearings. A sealed bearing is a bearing with sealing rings or seals on both its inner and outer sides. It can prevent flue gas leakage and the intrusion of external impurities, and also ensure the stable and smooth rotation of the first rotating shaft 13 / second rotating shaft 23.

[0060] In one specific embodiment of this utility model, in order to facilitate the control of the rotation of the first guide member 1 and the second guide member 2, the lower ends of the first rotating shaft 13 and the second rotating shaft 23 are respectively connected to the rotating shafts of the first rotating motor 14 and the second rotating motor 24. The first rotating motor 14 and the second rotating motor 24 are both located outside the lower part of the housing 6, which is convenient for control.

[0061] The rotation patterns of the first rotating motor 14 and the second rotating motor 24 can be set separately to control the direction changes of the blades of the first guide member 1 and the second guide member 2, so as to guide the flow velocity of flue gas in multiple directions within the shell 6.

[0062] Example 2

[0063] Figure 4 This is a schematic diagram of the flow path of the self-cleaning flue gas waste heat exchange device according to Embodiment 2 of this utility model.

[0064] like Figure 4 As shown, the self-cleaning flue gas waste heat exchange device provided in this embodiment, based on embodiment 1, controls the rotation of the first rotating motor 14 and the second rotating motor 24 respectively, and adjusts the blade direction of the first guide member 1 and the second guide member 2 to achieve the guide form of this embodiment.

[0065] In this embodiment, the first rotating motor 14 and the second rotating motor 24 can be controlled to rotate, so that the first connecting rod 12 of the first guide member 1 forms an acute angle with the width direction of the housing 6, and the second connecting rod 22 of the second guide member 2 forms an acute angle with the width direction of the housing 6, and the first connecting rod 12 and the second connecting rod 22 are parallel. This flow guiding form creates a vortex and a low-speed zone in the lower right of the heat exchange tube assembly 5, causing the flue gas to flow in an S-shaped path, avoiding ash accumulation and ensuring sufficient heat exchange.

[0066] Example 3

[0067] Figure 5 This is a schematic diagram of the flow path of the self-cleaning flue gas waste heat exchange device according to Embodiment 3 of this utility model.

[0068] like Figure 5 As shown, the self-cleaning flue gas waste heat exchange device provided in this embodiment, based on embodiment 1, controls the rotation of the first rotating motor 14 and the second rotating motor 24 respectively, and adjusts the blade direction of the first guide member 1 and the second guide member 2 to achieve the guide form of this embodiment.

[0069] In this embodiment, the first rotating motor 14 and the second rotating motor 24 can be controlled to rotate, so that the first connecting rod 12 of the first guide member 1 forms an acute angle with the width direction of the housing 6, and the second connecting rod 22 of the second guide member 2 forms an acute angle with the width direction of the housing 6, and the first connecting rod 12 and the second connecting rod 22 are symmetrical. This guiding form increases the flow velocity above the heat exchange tube assembly 5, and the flue gas flows in an arc-shaped path.

[0070] The alternating flue gas velocity makes it difficult for particulate matter to adhere stably to the surface of the heat exchange tube, thus reducing ash accumulation to some extent. The high-speed flow stage can also flush away the already deposited dust, removing some of the ash.

[0071] The controller can also rotate the first rotating motor 14 and the second rotating motor 24 to other angles to achieve different flow patterns for the first guide member 1 and the second guide member 2, thereby automatically eliminating the ash accumulation in the flue gas waste heat exchange device.

[0072] The self-cleaning flue gas waste heat exchange device according to the present invention is described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the self-cleaning flue gas waste heat exchange device proposed in the present invention without departing from the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. A self-cleaning flue gas waste heat exchange device, comprising a shell and a heat exchange tube assembly disposed within the shell, wherein the hot fluid inlet and hot fluid outlet of the shell are respectively located at the left and right ends of the shell, characterized in that, A first flow guide is provided inside the housing near the inlet of the hot fluid, and a second flow guide is provided inside the housing near the outlet of the hot fluid. The first guide member includes first blades that are uniformly and vertically arranged along the side of the heat exchange tube assembly toward the hot fluid inlet. The edges of all the first blades toward the hot fluid inlet are connected together by a first connecting rod. A vertical first rotating shaft is connected to the middle of the first connecting rod. The first rotating shaft passes through the housing and is connected to a first rotating motor. The second guide includes second blades that are uniformly and vertically arranged along the side of the heat exchange tube assembly toward the hot fluid outlet. The edges of all the second blades toward the hot fluid outlet are connected together by a second connecting rod. A vertical second rotating shaft is connected to the middle of the second connecting rod. The second rotating shaft passes through the housing and is connected to a second rotating motor.

2. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, The first blade and the second blade have the same shape and size.

3. The self-cleaning flue gas waste heat exchanger as described in claim 2, characterized in that, The first blade includes a trapezoidal plate and a rectangular plate connected to the long base of the trapezoidal plate. The length of the rectangular plate is the same as the long base of the trapezoidal plate. The rectangular plate and the trapezoidal plate are on the same plane. The short base of the trapezoidal plate is perpendicularly connected to the first connecting rod.

4. The self-cleaning flue gas waste heat exchanger as described in claim 3, characterized in that, The length of the rectangular plate is adapted to the inner height of the shell.

5. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, The spacing between adjacent first blades is the same as the spacing between adjacent second blades.

6. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, The number of both the first connecting rod and the second connecting rod is at least two.

7. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, The lengths of both the first connecting rod and the second connecting rod are less than the width of the housing.

8. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, Both ends of the first rotating shaft extend out of the housing and are rotatably connected to the housing via a first sealing ring; Both ends of the second rotating shaft extend out of the housing and are rotatably connected to the housing via a second sealing ring.

9. The self-cleaning flue gas waste heat exchanger as described in claim 8, characterized in that, Both the first sealing ring and the second sealing ring are sealed bearings.

10. The self-cleaning flue gas waste heat exchanger as described in claim 1, characterized in that, The lower ends of the first rotating shaft and the second rotating shaft are respectively connected to the rotating shafts of the first rotating motor and the second rotating motor.

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