Flue gas and tail gas waste heat utilization device for power generation of thermal power plant and use method thereof

Abstract

The flue gas and tail gas waste heat utilization device comprises a waste heat utilization box, the bottom of the waste heat utilization box is a cold water tank, the top of the waste heat utilization box is a cold and heat exchange box, a motor drives a transmission rod to rotate, and the transmission rod rotates to push a push plate to move through a second gear, a first gear and a second rotating rod; a push plate moves to push a connecting plate through a first rotating rod to drive a pull rod to move, and the pull rod moves to drive a cleaning plate to scrape condensate water at the top and the bottom of a cold-heat exchange box, so that the condensate water drips into a recycling box through a water collecting groove, and sulfur dioxide or nitric oxide contained in smoke and tail gas is prevented; and meanwhile, a pull rod moves to drive a cleaning plate to scrape off particles, fly ash and other impurities on the top of the cold and heat exchange box, the particles, the fly ash and other impurities fall into a recycling box, cleaning of the particles, the fly ash and other impurities is completed, and the cold and heat exchange efficiency is prevented from being reduced.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology, and in particular to a device for utilizing waste heat from flue gas exhaust in thermal power plants and its usage method. Background Technology

[0002] In thermal power plants, the recovery and utilization of waste heat from flue gas is considered an important means of improving energy efficiency. Since the flue gas emitted from boilers contains a large amount of waste heat, accounting for a significant proportion of the total heat loss in the boiler, the effective recovery and utilization of this heat energy is of great importance for improving unit operating efficiency and reducing coal consumption.

[0003] In existing technologies, heat from boiler exhaust gas is typically transferred to water or other media via heat exchange equipment to achieve waste heat recovery. However, in actual operation, heat exchange plates often face the following problems: Flue gas often carries unburned particulate matter and fly ash, which easily adhere to and deposit on the heat exchange plate surface, forming ash buildup and reducing heat transfer efficiency. If the exhaust gas temperature is lower than the flue gas dew point temperature, water vapor in the flue gas will condense into water droplets on the heat exchange surface. When the flue gas contains sulfur dioxide or nitrogen oxides, these gases dissolve in the condensate to form acidic substances, which can corrode the heat exchange plates and affect the equipment's service life.

[0004] To prevent the above problems from adversely affecting the system's operating efficiency and equipment safety, staff need to regularly clean the dust and particulate matter adhering to the heat exchange plates and drain the condensate in a timely manner to ensure the efficient and stable operation of the heat exchange system. Summary of the Invention

[0005] The purpose of this invention is to provide a waste heat recovery device for flue gas from thermal power plants and its usage method. The device aims to solve the corrosion and ash accumulation problems in waste heat recovery from flue gas in thermal power plants by automatically cleaning condensate and ash, intelligently monitoring dew point temperature, and centrally recovering pollutants, thereby achieving efficient, stable, and reliable waste heat recovery.

[0006] According to one objective of the present invention, the present invention provides a waste heat recovery device for flue gas from a thermal power plant, comprising a waste heat recovery box, a cold water tank at the bottom of the waste heat recovery box, a heat exchange box at the top of the waste heat recovery box, an inlet pipe and an outlet pipe connected to the left and right sides of the heat exchange box respectively, a cover plate bolted to the back of the heat exchange box, a plurality of support rods fixed to the inner side of the cover plate, a heat exchange box connected to the other end of each support rod, and a water absorption assembly connected to each heat exchange box for drawing cold water from the cold water tank into the heat exchange box; a cleaning plate connected to the top and bottom of each heat exchange box, a pull rod fixed to the center of the cleaning plate, the pull rod passing through the cover plate and slidably connected, a connecting plate fixed to the outer end of the cleaning plate, a driving assembly provided above the connecting plate for driving the pull rod to reciprocate; a recovery box connected to the bottom of the cover plate, the recovery box being located below the last heat exchange box.

[0007] Furthermore, the water absorption assembly includes water pipes respectively connected to the left and right sides of the heat exchange box, a water supply pipe inserted into the water pipes, a first telescopic water pipe, a water supply pipe, a water pump, a second telescopic water pipe, and a return pipe; the first telescopic water pipe is slidably connected to the water supply pipe, the water supply pipe is connected to the cold water tank and is equipped with the water pump; the second telescopic water pipe is slidably connected to the return pipe, the return pipe is connected to the cold water tank.

[0008] Furthermore, both the first and second telescopic water pipes have fixing blocks on their outer surfaces, and a threaded rod is rotatably connected to the outside of the fixing block. The threaded rod is threadedly connected to the heat exchange box.

[0009] Furthermore, a first mounting plate is fixed to the outer surface of the water pipe, a sealing ring is inserted into the first mounting plate, and a second mounting plate is fixed to the other side of the sealing ring. The second mounting plate is fixedly connected to the outer surface of the water pipe.

[0010] Furthermore, the drive assembly includes a first rotating rod rotatably connected to the connecting plate, a push plate fixed to the first rotating rod, a second rotating rod rotatably connected to the push plate, a first gear fixed to the second rotating rod, a rotating rod coaxially fixed to the first gear, a support plate, a motor, a transmission rod, and a second gear fixed to the transmission rod; the second gear meshes with the first gear, and the motor drives the second gear to rotate through the transmission rod.

[0011] Furthermore, several water collection tanks are arranged at equal intervals on both sides of the heat exchange box.

[0012] Furthermore, the diameter of the smoke inlet pipe is larger than the diameter of the smoke outlet pipe.

[0013] Furthermore, the front of the heat exchange box is provided with a high-temperature resistant observation window; the inside of the cover plate is provided with a number of first high-temperature resistant temperature sensors, each corresponding to one of the heat exchange boxes.

[0014] Furthermore, a high-temperature humidity sensor and a second high-temperature temperature sensor are provided on the top of the inner wall of the heat exchange box; a controller is provided on the side of the waste heat recovery box, which is electrically connected to the humidity sensor, the first high-temperature temperature sensor, the second high-temperature temperature sensor, the motor and the water pump respectively.

[0015] According to another objective of the present invention, the present invention provides a method for utilizing the waste heat of the above-mentioned flue gas exhaust waste heat utilization device, comprising the following steps: Flue gas enters the heat exchange box through the flue pipe, and the water pump sends cold water into the heat exchange box for heat exchange; the humidity RH, temperature T and the surface temperature T1 of the heat exchange box are detected by sensors and transmitted to the controller. The controller calculates the dew point temperature T based on the dew point temperature formula. d When T d When T1 is ≥, start the motor to drive the cleaning plate to scrape off condensate and impurities; Condensate flows into the recycling bin through the water collection tank, and impurities are scraped off into the recycling bin; the recycling bin is cleaned regularly.

[0016] This invention utilizes a motor-driven cleaning mechanism to automatically scrape away condensate and dust from the surface of the heat exchange box, effectively preventing acid corrosion and reduced heat exchange efficiency. Employing a high-temperature sensor and intelligent control system, it monitors temperature and humidity in real time and calculates the dew point temperature, precisely triggering the cleaning action for automated operation. The unique design of the water collection tank and recovery box enables centralized collection and cleaning of condensate and particulate matter. This device not only extends equipment lifespan and reduces maintenance costs but also improves waste heat recovery efficiency and system operational stability, resulting in significant energy-saving and environmental benefits. Attached Figure Description

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

[0018] Figure 1 This is a front view of an embodiment of the present invention. Figure 2 This is a schematic diagram of the right side of an embodiment of the present invention; Figure 3 This is a cross-sectional view of the heat exchange box according to an embodiment of the present invention; Figure 4 This is a cross-sectional structural diagram of an embodiment of the present invention; Figure 5 This is an embodiment of the present invention. Figure 4 Enlarged structural diagram at point A; Figure 6 This is a schematic diagram of the structure of the driving component according to an embodiment of the present invention; Figure 7 This is a cross-sectional view of the back of the heat exchange box according to an embodiment of the present invention; Figure 8 This is a schematic cross-sectional view of the right side of the heat exchange box according to an embodiment of the present invention.

[0019] In the diagram: 1. Waste heat recovery box; 2. Cold water tank; 3. Heat exchanger box; 4. Smoke inlet pipe; 5. Smoke outlet pipe; 6. Cover plate; 7. Heat exchanger box; 71. Water collection tank; 8. Water pipe; 9. First mounting plate; 10. Sealing ring; 11. Second mounting plate; 12. Water supply pipe; 13. First telescopic water pipe; 14. Water supply pipe; 15. Water pump; 16. Second telescopic water pipe; 161. Return pipe; 17. Fixing block; 18. Threaded rod; 19. Recovery box; 20. Cleaning plate; 21. Pull rod; 22. Connecting plate; 23. First rotating rod; 24. Push plate; 25. Second rotating rod; 26. First gear; 27. Rotating rod; 28. Support plate; 29. ​​Motor; 30. Transmission rod; 31. Second gear. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] Furthermore, the terms "first" and "second" 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] Example 1 like Figures 1-8 As shown, a waste heat recovery device for flue gas in a thermal power plant includes a waste heat recovery box 1, a cold water tank 2 at the bottom of the waste heat recovery box 1, a heat exchange box 3 at the top of the waste heat recovery box 1, and a high-temperature resistant observation window fixedly installed on the front of the heat exchange box 3 to facilitate staff to observe the internal conditions of the heat exchange box 3.

[0024] The left and right sides of the heat exchange box 3 are respectively fixedly connected to the inlet pipe 4 and the exhaust pipe 5. The diameter of the inlet pipe 4 is larger than that of the exhaust pipe 5 to reduce the speed at which the flue gas flows out of the heat exchange box 3. The back of the heat exchange box 3 is fixedly connected to the cover plate 6 by bolts. Several support rods are fixedly connected to the inside of the cover plate 6. The other end of each support rod is fixedly connected to the heat exchange box 7. Each heat exchange box 7 is connected to a water absorption assembly on its side. The water absorption assembly is used to draw cold water from the cold water tank 2 into the heat exchange box 7. The water intake assembly includes a water pipe 8, a water delivery pipe 12, a first telescopic water pipe 13, a water supply pipe 14, a water pump 15, a second telescopic water pipe 16, and a return pipe 161. Water pipes 8 are connected to both the left and right sides of the heat exchange box 7. A first mounting plate 9 is fixedly connected to the surface of each water pipe 8. A sealing ring 10 is inserted into the inside of the first mounting plate 9. A second mounting plate 11 is fixedly connected to the other side of the sealing ring 10. The inside of the second mounting plate 11 is fixedly connected to the surface of the water delivery pipe 12, and the inside of both water pipes 8 is inserted into the two water delivery pipes 12. One end of the right-side water delivery pipe 12 is connected to the inside of the first telescopic water pipe 13. The bottom of the first telescopic water pipe 13 is slidably connected to the water supply pipe 14. The other end of the water supply pipe 14 is connected to the cold water tank 2. The inside of the water supply pipe 14 is connected to the water pump 15, allowing the water pump 15 to draw water through the water supply pipe 14. The left... One end of the side water supply pipe 12 is connected to a second telescopic water pipe 16. The bottom of the second telescopic water pipe 16 is slidably connected to a return pipe 161 connected to the cold water tank 2. The surfaces of the second telescopic water pipe 16 and the first telescopic water pipe 13 are both fixedly connected to a fixing block 17. The outer side of the fixing block 17 is rotatably connected to a threaded rod 18, and the surface of the threaded rod 18 is threadedly connected to the heat exchange box 3. By setting up the second mounting plate 11, the water supply pipe 12, the first telescopic water pipe 13, the fixing block 17, and the threaded rod 18, the rotation of the threaded rod 18 pushes the fixing block 17 to move the first telescopic water pipe 13. The movement of the first telescopic water pipe 13 causes the water supply pipe 12 to be inserted into the interior of the water pipe 8. At the same time, the water supply pipe 12 drives the second mounting plate 11 to push the sealing ring 10 into the interior of the first mounting plate 9, thus completing the rapid connection between the water supply pipe 12 and the water pipe 8.

[0025] Several water collection tanks 71 are provided on both sides of the heat exchange box 7, and the water collection tanks 71 are arranged at equal intervals on the sides of the heat exchange box 7. The heat exchange boxes 7 are arranged at equal intervals in the internal space of the heat exchange chamber 3. Each heat exchange box 7 has a cleaning plate 20 connected to its top and bottom. A pull rod 21 is fixedly connected to the center of the cleaning plate 20. The surface of the pull rod 21 is slidably connected to the cover plate 6. A connecting plate 22 is fixedly connected to one end of the pull rod 21 that passes through the cover plate 6. The top of the connecting plate 22 is provided with a drive assembly that drives the connecting plate 22 to drive the pull rod 21 to reciprocate. The drive assembly includes a first rotating rod 23, a push plate 24, a second rotating rod 25, a first gear 26, a rotating rod 27, a support plate 28, a motor 29, a transmission rod 30, and a second gear 31. The top of the connecting plate 22 is rotatably connected to the surface of the first rotating rod 23. The top of the first rotating rod 23 is fixedly connected to one side of the push plate 24. The other side of the push plate 24 is rotatably connected to the surface of the second rotating rod 25. The top of the second rotating rod 25 is fixedly connected to the surface of the first gear 26. The center of the first gear 26 is fixedly connected to the surface of the rotating rod 27. The surface of the rotating rod 27 is rotatably connected to the interior of the support plate 28. One side of the support plate 28 is fixedly connected to the top of the heat exchange box 3. The top of the support plate 28 is fixedly connected to the surface of the motor 29. The output shaft of the motor 29 is connected to the transmission rod 30. The surface of the transmission rod 30 is fixedly connected to the interior of the second gear 31. The second gear 31 meshes with the first gear 26. A recycling box 19 is bolted to the bottom of the cover plate 6, and the recycling box 19 is located directly below the last heat exchange box 7; the recycling box 19 is used to recycle impurities and condensate that fall from the heat exchange box 7. Several first high-temperature resistant temperature sensors are fixedly connected to the inner side of the cover plate 6. Each first high-temperature resistant temperature sensor corresponds to a heat exchange box 7, allowing the first high-temperature resistant temperature sensor to detect the surface temperature of the heat exchange box 7. A high-temperature resistant humidity sensor is provided on the top of the inner wall of the heat exchange box 3 to detect whether condensation occurs on the surface of the heat exchange box 7. A second high-temperature resistant temperature sensor is provided on the top of the inner wall of the heat exchange box 3 to detect the internal temperature of the heat exchange box 3. The second high-temperature resistant temperature sensor is used to detect the temperature of the air inside the heat exchange box 3. A controller is fixedly connected to the side of the waste heat recovery box 1. A chip is installed inside the controller, and the chip is used for... The controller processes information from the high-temperature and high-temperature humidity sensors and controls the start and stop of water pump 15 and motor 29 respectively. The chip contains a dew point temperature meter. The controller is electrically connected to the humidity sensor, the first high-temperature humidity sensor, the second high-temperature humidity sensor, motor 29, and water pump 15. By configuring the controller, humidity sensor, and high-temperature temperature sensor, the controller transmits the humidity values ​​detected by the first and second high-temperature humidity sensors and the internal temperature of the heat exchange box 3 detected by the high-temperature temperature sensor to the controller. The controller then calculates the dew point temperature using the dew point temperature calculation formula. To make a comparison, when This can cause condensation to appear on the surface of the heat exchange box 7.

[0026] The waste heat recovery device for flue gas from thermal power plants, as described in this invention, is used as follows: The flue gas and exhaust gas enter the interior of the heat exchange box 3 through the flue gas inlet pipe 4. At the same time, the controller controls the water pump 15 to start, so that the water pump 15 delivers the cold water in the cold water tank 2 to the interior of the first telescopic water pipe 13 through the water supply pipe 14. Then, the cold water enters the interior of the heat exchange box 7 through the first telescopic water pipe 13, the water supply pipe 12, and the water pipe 8 in sequence. At the same time, the interior of the heat exchange box 3 is filled with flue gas and exhaust gas and exchanges heat with the heat exchange box 7. The heat in the flue gas and exhaust gas heats the cold water inside the heat exchange box 7. The heated water is discharged from the water pipe 8 on the other side of the heat exchange box 7. The heated water is discharged into the interior of the cold water tank 2 through the water pipe 8 on the right side, the water supply pipe 12, the second telescopic water pipe 16, and the return pipe 161 in sequence, completing the cold water circulation inside the cold water tank 2. The flue gas and exhaust gas entering the heat exchange box 3 continuously heat the cold water. When the flue gas and exhaust gas first enter the heat exchanger 3, cold water exchanges heat with the flue gas and exhaust gas, reducing their temperature. The humidity value is then detected by a high-temperature humidity sensor. The first high-temperature resistant temperature sensor detects the temperature value T inside the heat exchange box 3, and the second high-temperature resistant temperature sensor detects the temperature value T1 on the surface of the heat exchange box 7. These values ​​are transmitted to the controller, which then calculates the dew point temperature using the formula: ; T, T1, T d The unit is ℃; The unit is: % 6.112 is the reference saturated vapor pressure, in hPa; 7.62 Empirical coefficients of the Magnus formula; 243.12 Empirical coefficients of the Magnus formula, in °C; Calculate the dew point temperature T d To make a comparison, when T d When T1 is greater than or equal to 1, condensation will appear on the surface of the heat exchange box 7. The controller starts the motor 29, which drives the transmission rod 30 to rotate. The rotation of the transmission rod 30 drives the second gear 31 to rotate, which in turn drives the first gear 26 to rotate. The rotation of the first gear 26 pushes the push plate 24 to move via the second rotating rod 25. The movement of the push plate 24 pushes the connecting plate 22 via the first rotating rod 23, which in turn moves the pull rod 21. The pull rod 21 moves along with the cleaning plate 20, which scrapes away the condensate from the top and bottom of the heat exchange box 7. At the same time, the water collection tank 71 on the side of the heat exchange box 7 collects the condensate, which drips into the inside of the recovery box 19. This prevents sulfur dioxide or nitrogen oxides in the flue gas and exhaust gas from dissolving in the condensate to form an acidic solution, which could then corrode the heat exchange box 7. When the flue gas and exhaust gas first enter the interior of the heat exchange box 3, unburned particulate matter, fly ash and other impurities in the flue gas and exhaust gas are deposited on the surface of the heat exchange plate. At the same time, the drive component drives the recovery box 19 through the connecting plate 22 and the pull rod 21 to push the particulate matter, fly ash and other impurities on the top of the heat exchange box 7 into the recovery box 19, thus cleaning the particulate matter, fly ash and other impurities and preventing the efficiency of heat exchange from decreasing.

[0027] Staff need to periodically remove the recycling bin 19 from inside the heat exchange box 3 and clean out any impurities inside the recycling bin 19.

[0028] This invention uses a motor to drive a transmission rod to rotate, which in turn drives a second gear to rotate, which in turn drives a first gear to rotate. The rotation of the first gear, in turn, drives a push plate to move via a second rotating rod. The movement of the push plate, in turn, drives a connecting plate via the first rotating rod, which in turn drives a pull rod to move. The pull rod's movement causes a cleaning plate to scrape away the condensate from the top and bottom of the heat exchange box. Simultaneously, a water collection tank on the side of the heat exchange box collects the condensate, allowing it to drip into the inside of the recovery tank. This prevents sulfur dioxide or nitrogen oxides in the flue gas and exhaust gas from dissolving in the condensate to form an acidic solution that could corrode the heat exchange box. The pull rod's movement also causes the cleaning plate to scrape away particulate matter, fly ash, and other impurities from the top of the heat exchange box, which then fall into the recovery tank. This completes the cleaning of particulate matter, fly ash, and other impurities, preventing a decrease in the efficiency of the heat exchange.

[0029] This invention transmits the humidity values ​​detected by the first and second high-temperature humidity sensors and the internal temperature of the heat exchange box detected by the high-temperature temperature sensor to the controller. The controller then calculates the dew point temperature according to the dew point temperature calculation formula and compares the results. When the surface temperature of the heat exchange box is less than or equal to the dew point temperature, condensation will occur on the surface of the heat exchange box, thus achieving accurate detection of condensation on the surface of the heat exchange box.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for utilizing waste heat from flue gas generated in a thermal power plant, characterized in that, The device includes a waste heat recovery box, with a cold water tank at the bottom and a heat exchange box at the top. A flue gas inlet pipe and an exhaust pipe are connected to the left and right sides of the heat exchange box, respectively. A cover plate is bolted to the back of the heat exchange box, and several support rods are fixed inside the cover plate. Each support rod is connected to a heat exchange box at its other end, and each heat exchange box is connected to a water absorption assembly for drawing cold water from the cold water tank into the heat exchange box. A cleaning plate is connected to the top and bottom of each heat exchange box, with a pull rod fixed to the center of the cleaning plate. The pull rod passes through the cover plate and is slidably connected. A connecting plate is fixed to the outer end of the cleaning plate, and a driving assembly is located above the connecting plate to drive the pull rod in reciprocating motion. A recycling box is connected to the bottom of the cover plate and is located below the last heat exchange box.

2. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The water absorption assembly includes water pipes connected to the left and right sides of the heat exchange box, a water supply pipe inserted into the water pipes, a first telescopic water pipe, a water supply pipe, a water pump, a second telescopic water pipe, and a return pipe; the first telescopic water pipe is slidably connected to the water supply pipe, the water supply pipe is connected to the cold water tank and is equipped with the water pump; the second telescopic water pipe is slidably connected to the return pipe, the return pipe is connected to the cold water tank.

3. The waste heat recovery device for flue gas from thermal power plants according to claim 2, characterized in that, Both the first and second telescopic water pipes have fixing blocks on their outer surfaces. A threaded rod is rotatably connected to the outside of the fixing block, and the threaded rod is threadedly connected to the heat exchange box.

4. The waste heat recovery device for flue gas from thermal power plants according to claim 2, characterized in that, A first mounting plate is fixed to the outer surface of the water pipe, a sealing ring is inserted into the first mounting plate, and a second mounting plate is fixed to the other side of the sealing ring. The second mounting plate is fixedly connected to the outer surface of the water pipe.

5. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The drive assembly includes a first rotating rod rotatably connected to a connecting plate, a push plate fixed to the first rotating rod, a second rotating rod rotatably connected to the push plate, a first gear fixed to the second rotating rod, a rotating rod coaxially fixed to the first gear, a support plate, a motor, a transmission rod, and a second gear fixed to the transmission rod; the second gear meshes with the first gear, and the motor drives the second gear to rotate through the transmission rod.

6. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, Several equally spaced water collection tanks are opened on both sides of the heat exchange box.

7. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The diameter of the smoke inlet pipe is larger than the diameter of the smoke outlet pipe.

8. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The front of the heat exchange box is provided with a high-temperature resistant observation window; the inside of the cover plate is provided with a number of first high-temperature resistant temperature sensors, each corresponding to one of the heat exchange boxes.

9. The waste heat recovery device for flue gas from thermal power plants according to claim 8, characterized in that, The top of the inner wall of the heat exchange box is equipped with a high-temperature humidity sensor and a second high-temperature temperature sensor; the side of the waste heat recovery box is equipped with a controller, which is electrically connected to the humidity sensor, the first high-temperature temperature sensor, the second high-temperature temperature sensor, the motor and the water pump respectively.

10. The waste heat utilization method of the waste heat utilization device for flue gas exhaust gas from thermal power plants according to any one of claims 1-9, characterized in that, Includes the following steps: Flue gas enters the heat exchange box through the flue pipe, and the water pump sends cold water into the heat exchange box for heat exchange; the humidity RH, temperature T and the surface temperature T1 of the heat exchange box are detected by sensors and transmitted to the controller. The controller calculates the dew point temperature T based on the dew point temperature formula. d When T d When T1 is ≥, start the motor to drive the cleaning plate to scrape off condensate and impurities; Condensate flows into the recycling bin through the water collection tank, and impurities are scraped off into the recycling bin; the recycling bin is cleaned regularly.

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