Dustproof device for dry slag discharge system of thermal power plant

Abstract

A dust prevention device for a dry slag discharge system of a thermal power plant, comprising a flow guide cylinder arranged between a slag bin and a slag discharge port, a cyclone separation chamber arranged in the flow guide cylinder, a tangential inlet hole connected to a high-pressure air source arranged on a side wall of the flow guide cylinder, and a spiral flow guide rib arranged on an inner wall of the flow guide cylinder; a cooling coil is wound on an outer wall of the flow guide cylinder, and an outlet of the cooling coil is connected to a pipeline of a negative pressure dust collection system through a heat exchanger; a telescopic cylinder is arranged at a bottom of the slag discharge port, an impeller is arranged in the telescopic cylinder, the impeller drives a ring-shaped rotor on an outer wall of the telescopic cylinder to rotate through magnetic coupling, the ring-shaped rotor rubs against a ring-shaped stator to generate electricity, and the ring-shaped rotor supplies power to a conductive thorn ring; a ring-shaped elastic sealing ring with folds and a vertical deformation mechanism are connected to a lower end of the telescopic cylinder; the negative pressure dust collection system comprises two-stage dust collection units arranged below an outer periphery of the flow guide cylinder and an outer periphery of the sealing ring respectively. The dust prevention device utilizes the synergistic effect of cyclone separation, cooling and heat exchange, self-powered electrostatic dust removal and staged negative pressure dust collection, and realizes efficient dust prevention during the slag discharge process.

Description

Technical Field

[0001] This invention relates to a dust prevention device for a dry ash discharge system in a thermal power plant, belonging to the technical field of dry ash discharge technology in thermal power plants. Background Technology

[0002] Dust is inevitably generated during the slag unloading process. With my country’s increasingly stringent requirements for fugitive emissions, thermal power plants have taken measures to control dust during the slag unloading process. The main method is to add negative pressure dust collection at the slag discharge port and send the dust-laden gas to the bag filter. The dust is collected by the bag filter and then disposed of in a unified manner.

[0003] Chinese patent CN117927958A discloses a dust removal device and method for a slag bin in a thermal power plant's dry slag machine. The device includes a dust collection hood installed at the slag discharge port of the slag bin. The dust collection hood is connected to the horizontal section of an air-cooled dry slag machine via a pipe. The negative pressure generated by the horizontal section of the air-cooled dry slag machine provides the suction force required for dust collection. The dust-laden gas collected by the dust collection hood serves as the cooling air for the air-cooled dry slag machine. After cooling the slag on the conveyor belt, the gas is sent into the furnace. A pipe damper is installed on the pipe. During slag discharge from the slag bin, the opening of the pipe damper is adjusted according to the discharge volume and dust levels to regulate the dust collection hood. The solution utilizes the negative pressure of the furnace itself to complete dust removal from the slag bin of the dry slag machine, without the need for additional cold air entering the furnace, and without the need for traditional filter surfaces such as bags. It can adapt to both dry and wet slag discharge conditions. However, this solution still mainly relies on external negative pressure sources and pipeline air volume adjustment to achieve dust collection. It does not pay enough attention to issues such as gas-solid separation during the descent process from the slag bin to the slag truck hopper, condensation or fine ash escape caused by hot and humid airflow, dynamic adaptation of the expansion seal, energy consumption and structural complexity of the dust collection process, and it is difficult to achieve a more thorough and efficient dust prevention and removal effect under complex working conditions. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the existing technology, the present invention provides a dust prevention device for the dry ash discharge system of thermal power plants, which realizes efficient dust prevention during the ash discharge process.

[0005] The technical solution of the present invention is as follows: A dust control device for a dry ash discharge system in a thermal power plant includes a guide cylinder positioned between the ash bin and the ash discharge port. A telescopic cylinder is installed at the bottom of the ash discharge port, and a sealing base is connected to the lower end of the telescopic cylinder, allowing it to extend and retract vertically. A vibrating assembly is fixed externally to the guide cylinder and the telescopic cylinder. The sealing base is positioned between the lower end of the telescopic cylinder and the ash truck hopper, and includes an annular elastic sealing ring connected to the telescopic cylinder and a vertical deformation mechanism for controlling the vertical contraction of the telescopic cylinder. The device also includes a negative pressure dust collection system for collecting discharged ash. The dust generated during the process; the guide tube is equipped with a cyclone separation chamber, and the inner wall of the cyclone separation chamber is evenly distributed with multiple spiral guide ribs along the circumference, and the side wall of the cyclone separation chamber is tangentially opened with multiple air inlets, which are connected to a high-pressure air source; the outer wall of the guide tube is wrapped with a cooling coil, and a cooling medium flows in the cooling coil. The inlet of the cooling coil is connected to a cooling medium supply pump, and the outlet of the cooling coil is connected to a heat exchanger. The other end of the heat exchanger is connected to the pipeline of the negative pressure dust collection system for preheating the airflow entering the negative pressure dust collection system.

[0006] The telescopic cylinder contains an impeller coaxially mounted inside. The impeller includes a hub and multiple blades fixed circumferentially to the outer periphery of the hub. The windward side of the blades faces downward towards the telescopic cylinder, and the leeward side faces towards the guide tube. A magnetically coupled inner magnetic ring is embedded within the hub, with its magnetic poles alternately arranged circumferentially. An annular rotor is rotatably mounted on the outer wall of the telescopic cylinder via bearings. A magnetically coupled outer magnetic ring is embedded in the inner wall of the annular rotor, with its magnetic poles alternately arranged circumferentially and corresponding one-to-one with the magnetic poles of the magnetically coupled inner magnetic ring. The annular rotor and the impeller are driven by magnetic coupling. The annular rotor rotates synchronously with the impeller; an annular stator is fixed at the lower end of the slag discharge port, and the annular stator is sleeved on the outer circumference of the annular rotor; the inner wall surface of the annular stator is covered with a first friction layer, which is a polytetrafluoroethylene film or a perfluoroethylene propylene copolymer film; the outer wall surface of the annular rotor is covered with a second friction layer, which is a nylon film or aluminum foil; the first friction layer and the second friction layer maintain contact or micro-gap contact; the annular stator and the annular rotor are respectively connected to a rectifier energy storage circuit through wires, and the output terminal of the rectifier energy storage circuit is connected to a conductive barbed ring.

[0007] The conductive barb ring is fixedly installed on the inner wall of the telescopic cylinder. The conductive barb ring includes an annular insulating base and multiple conductive barbs that are uniformly fixed on the annular insulating base along the circumference. The tips of the conductive barbs face the inner wall of the telescopic cylinder. The cross-section of the annular insulating base is wedge-shaped, and its upper surface is an inwardly inclined slope covered with a dust-repellent coating. The telescopic cylinder is connected to the ground through a grounding wire.

[0008] The cyclone separation chamber includes a cylindrical section and a conical section. The air inlet and the spiral guide rib are opened on the side wall of the cylindrical section. The cross-section of the spiral guide rib is trapezoidal and the pitch gradually decreases from top to bottom. The bottom opening of the conical section is connected to the slag discharge port, and the inner wall of the conical section is covered with a ceramic wear-resistant coating.

[0009] The negative pressure dust collection system includes a first negative pressure dust collection unit and a second negative pressure dust collection unit. The first negative pressure dust collection unit is located on the outer periphery of the guide tube and includes a first dust collector and a first negative pressure fan. The first dust collector is connected to the negative pressure suction port on the guide tube and is also connected to the first negative pressure fan. The second negative pressure dust collection unit includes a suction hood, a second dust collector, and a second negative pressure fan. The second suction hood is arranged around the lower outer periphery of the annular elastic sealing ring and is connected to the second dust collector. The second dust collector is also connected to the second negative pressure fan. The outlets of the first and second negative pressure fans are connected to the same instrument compressed air source.

[0010] The vertical deformation mechanism includes at least two circumferentially distributed electric push rods and a pressure-sensitive trigger switch. The cylinder end of each electric push rod is fixed to the lower end face of the slag discharge port, and the push rod end of each electric push rod extends vertically downward and is fixedly connected to the lower end of the telescopic cylinder. The pressure-sensitive trigger switch is installed on the bottom surface of the annular elastic sealing ring and electrically connected to the control end of each electric push rod. When the pressure-sensitive trigger switch detects that the bottom pressure is lower than a first preset threshold, it controls the push rod of each electric push rod to drive the annular elastic sealing ring down to fit the edge of the slag truck hopper. When the pressure-sensitive trigger switch detects that the bottom pressure is higher than a second preset threshold, it controls the push rod of each electric push rod to retract synchronously, causing the annular elastic sealing ring to rise and disengage from the edge of the slag truck hopper.

[0011] The annular elastic sealing ring is made of elastic rubber or elastic fabric, and its lower end hangs down naturally to form a free end. The annular elastic sealing ring remains in a contracted state in its natural state. The cylindrical wall of the annular elastic sealing ring is uniformly provided with multiple pleats along the circumference, so that the annular elastic sealing ring has the ability to expand elastically in the radial and circumferential directions.

[0012] The present invention has the following beneficial effects: This invention features a cyclone separation chamber inside the guide tube. Multiple spiral guide ribs are evenly distributed circumferentially on the inner wall of the cyclone separation chamber, and multiple air inlets connected to a high-pressure air source are tangentially opened on the side wall of the cyclone separation chamber. This allows for gas-solid pre-separation after the dry slag enters the guide tube, causing coarse slag to slide down the wall and fine ash to accumulate in the central area. This reduces the fine ash content entering the downstream telescopic cylinder and lowers the subsequent dust removal burden.

[0013] This invention uses a cooling coil wound around the outer wall of a guide tube. The inlet of the cooling coil is connected to a cooling medium supply pump, and the outlet is connected to a heat exchanger. The other end of the heat exchanger is connected to the pipeline of a negative pressure dust collection system. This achieves the transfer of excess heat from the wall of the guide tube to the airflow of the negative pressure dust collection system, thereby suppressing the dust aggravation caused by gas expansion inside the guide tube and preheating the airflow to improve the working conditions of the dust collector.

[0014] This invention utilizes an impeller coaxially mounted inside a telescopic cylinder, with the impeller blades facing downwards from the telescopic cylinder and leewards towards the guide cylinder. A magnetically coupled inner magnetic ring is embedded in the impeller hub. A ring rotor is mounted on the outer wall of the telescopic cylinder via bearings, and a magnetically coupled outer magnetic ring is embedded in the inner wall of the ring rotor. The ring rotor and impeller are driven by magnetic coupling. A ring stator is fixed at the lower end of the slag discharge port. The inner wall of the ring stator is covered with a first friction layer, and the outer wall of the ring rotor is covered with a second friction layer. The ring stator and ring rotor are connected to a rectifier energy storage circuit via wires. The output of the rectifier energy storage circuit is connected to a conductive barbed ring. This invention achieves the effect of using the falling slag flow to drive the impeller to rotate, and through magnetic coupling, driving the ring rotor and ring stator to generate electricity through friction, providing the electrical energy required for electrostatic dust removal to the conductive barbed ring. This results in self-powered electrostatic dust removal without the need for an external power source.

[0015] This invention uses conductive barbed rings fixedly installed on the inner wall of a telescopic cylinder. The tips of the conductive barbs face the inner wall of the telescopic cylinder and maintain a gap with the inner wall. The telescopic cylinder is connected to the ground through a grounding wire, which realizes the formation of a corona discharge area between the tips of the barbs and the inner wall of the telescopic cylinder. This causes the falling fine ash to be charged and adsorbed on the wall surface, achieving the effect of continuous electrostatic capture of fine ash in the airflow during the slag discharge process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the dust prevention device for a dry ash discharge system in a thermal power plant according to the present invention. Figure 2 This is a schematic diagram of the internal structure of the guide tube of the present invention; Figure 3 This is a schematic diagram of the internal structure of the telescopic cylinder of the present invention.

[0017] The reference numerals in the figure are as follows: 1. Slag bin; 2. Flow guide cylinder; 21. Spiral flow guide rib; 22. Air inlet; 23. Cooling coil; 24. Cooling medium supply pump; 25. Heat exchanger; 3. Telescopic cylinder; 31. Blades; 32. Magnetic coupling inner magnetic ring; 33. Annular rotor; 34. Magnetic coupling outer magnetic ring; 35. Annular stator; 36. Annular insulating substrate; 37. Conductive barbs; 4. Sealing base; 41. Annular elastic sealing ring; 5. Vibration assembly; 51. First dust collector; 52. First negative pressure fan; 53. Negative pressure dust suction port; 54. Second dust suction hood; 55. Second dust collector; 56. Second negative pressure fan; 6. Electric push rod. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] Please see Figures 1 to 3 The invention provides a technical solution: A dust control device for a dry ash discharge system in a thermal power plant includes a guide tube 2 installed between the ash bin 1 and the ash discharge port. The guide tube 2 serves as the primary channel for dry ash to enter downstream equipment from the ash bin 1. It is equipped with a cyclone separation chamber. The inner wall of the cyclone separation chamber has multiple spiral guide ribs 21 evenly distributed circumferentially, and multiple air inlets 22 are tangentially opened on the side wall of the cyclone separation chamber. The air inlets 22 are connected to a high-pressure gas source. When the high-pressure gas is injected from the tangential air inlets 22, a high-speed rotating airflow is formed in the cyclone separation chamber. After the dry ash enters the cyclone separation chamber, the coarse ash is thrown against the wall under the action of centrifugal force and slides down along the spiral guide ribs 21, while the fine ash accumulates in the central area. The purpose of cyclone separation is to separate coarse slag and fine ash before they enter the downstream, so as to prevent fine ash from being mixed with coarse slag and falling down and escaping over a large area at the slag discharge port. Without this pre-separation, a large amount of fine ash will fall down with the coarse slag and be swept up by the falling airflow at the slag discharge port, forming serious dust. After cyclone separation, most of the fine ash has been concentrated in the central area and can be efficiently sucked away by the negative pressure dust collection system. The ash content in the remaining coarse slag is greatly reduced, and even if there is a small amount of dust, it is easy to control. A telescopic cylinder 3 is installed at the bottom of the slag discharge port. The lower end of the telescopic cylinder 3 is connected to a sealing base 4 and can extend and retract in the vertical direction. The function of the telescopic cylinder 3 is to adjust the distance between the slag discharge port and the slag bucket according to the actual height of the slag truck bucket, so as to shorten the free fall of the dry slag as much as possible and reduce the dust caused by the fall impact. The guide cylinder 2 and the telescopic cylinder 3 are fixed with a vibrating component 5. The function of the vibrating component 5 is to apply mechanical impact to the wall surface of the guide cylinder 2 and the telescopic cylinder 3 periodically or continuously, shake off the slag adhering to the wall surface, prevent the slag from thickening and causing the channel to be blocked or the telescopic cylinder 3 to get stuck. At the same time, the vibration also helps to break the scale layer that may form on the wall surface and keep the channel unobstructed. The sealing base 4 is located between the lower end of the telescopic cylinder 3 and the slag truck bucket. The sealing base 4 includes an annular elastic sealing ring 41 connected to the telescopic cylinder 3 and a vertical deformation mechanism for controlling the vertical contraction of the telescopic cylinder 3. The annular elastic sealing ring 41 remains contracted in its natural state. When the telescopic cylinder 3 descends and the sealing ring contacts the bucket or the material surface, the annular elastic sealing ring 41 expands elastically under the contact pressure and fits the material surface to form a dynamic seal. The vertical deformation mechanism adjusts the height of the telescopic cylinder 3 in real time according to the change of the bottom pressure of the annular elastic sealing ring 41, so that the annular elastic sealing ring 41 always maintains an appropriate contact pressure with the material surface, neither too tight, which would cause too much wear, nor too loose, which would cause ash leakage. Cooling coil 23 is wound around the outer wall of guide tube 2. The inlet of cooling coil 23 is connected to cooling medium supply pump 24, and the outlet of cooling coil 23 is connected to the hot side inlet of heat exchanger 25. The hot side outlet of heat exchanger 25 is connected to the return pipeline of cooling medium supply pump 24. Cooling medium circulates between cooling coil 23, the hot side of heat exchanger 25 and cooling medium supply pump 24, carrying the heat absorbed by the wall of guide tube 2 to the heat exchanger 25 for release. The cold side inlet of heat exchanger 25 is connected to the air inlet pipeline of negative pressure dust collection system. The dust-laden airflow drawn into the guide tube 2 by the negative pressure dust collection system passes through the cold side channel of heat exchanger 25 before entering the first dust collector 51. After absorbing the heat released by the cooling medium, it is preheated. The preheated airflow flows out from the cold side outlet of heat exchanger 25 and then enters the first dust collector 51 for purification. The cooling coil 23 serves two purposes: Firstly, when the high-temperature dry slag flows inside the guide tube 2, it heats the tube wall and the internal air. The heated air expands, and the resulting hot airflow inside the guide tube 2 intensifies the dispersion of fine ash. That is, thermal expansion leads to an increase in internal pressure. The cooling coil 23 absorbs this excess heat, inhibits gas expansion, and thus reduces heat-induced dust. Secondly, the heat absorbed by the cooling coil 23 is not wasted. Instead, it is transferred to the dust-laden airflow drawn by the negative pressure dust collection system through the heat exchanger 25. This increases the temperature and reduces the relative humidity of the airflow entering the first dust collector 51. The dry airflow keeps the fine ash particles loose and prevents them from agglomerating and settling. At the same time, the preheated gas density decreases and the volumetric flow rate increases. Under the same fan power, the flow velocity increases, enhancing the ability to carry fine ash. This improves the overall efficiency of the dust collection system and helps prevent condensation and bag clogging inside the dust collector due to excessively low temperatures in wet slag discharge or low-temperature environments.

[0020] It should be noted that although the cooling coil 23 is wrapped around the outer wall of the guide tube 2 and continuously absorbs heat, its cooling medium inlet temperature is controlled within a certain margin above the dew point temperature of the airflow inside the guide tube 2 through the joint regulation of the cooling medium supply pump 24 and the heat exchanger 25. Therefore, the inner wall temperature of the guide tube 2 is always kept above the dew point temperature, and there will be no problem of water vapor in the dust-laden hot airflow condensing on the wall surface due to excessive wall cooling. Specifically, the cooling coil 23 only absorbs excess heat from the wall surface of the guide tube 2, reducing the wall surface temperature from an extremely high temperature to a reasonable intermediate temperature, rather than reducing the wall surface to a low temperature close to the cooling medium inlet temperature. At the same time, the high-temperature dry slag and hot airflow inside the guide tube 2 continue to flow downwards, constantly replenishing the heat to the wall surface, so that the wall surface temperature is maintained within a dynamic equilibrium range and will not continue to decrease. Furthermore, the cooling channels inside the spiral guide ribs 21 are also supplied with cooling medium through the cooling medium supply pump 24. The cooling medium temperature shares the same circulation loop as the cooling coil 23. Therefore, the rib surface temperature of the spiral guide ribs 21 is also controlled within a range above the dew point, preventing fine dust from condensing and adhering on the rib surface due to localized overcooling. This temperature control design allows the cooling coil 23 and spiral guide ribs 21 to suppress heat-induced dust and drive thermophoretic separation while avoiding the risk of dust accumulation and scaling caused by condensation.

[0021] In addition, the temperature of the cooled dry slag decreases when it enters the telescopic cylinder 3. The temperature change of the dry slag directly affects its physical form. High-temperature dry slag has high surface activity and strong electrostatic effect, and the adhesion between fine ash particles and between fine ash and the wall is large, making it easy to form scale and accumulate. After appropriate cooling, the electrostatic effect of the dry slag weakens, the adhesion between particles decreases, and it becomes looser, which is conducive to subsequent vibration cleaning and pneumatic conveying. At the same time, the loose dry slag is less likely to form large clumps when falling into the hopper, reducing secondary dust during the unloading process. It also includes a negative pressure dust collection system, which is used to collect the dust generated during the slag discharge process. The negative pressure dust collection system forms a negative pressure area near the guide cylinder 2 and the sealing base 4, which draws the escaping dust-laden airflow into the dust collector for purification. When the airflow, which has been preheated by the heat exchanger 25, enters the negative pressure dust collection system at a suitable temperature, it will not damage the filter bag due to excessive temperature, and it is also conducive to preventing condensation and bag clogging inside the first dust collector 51 due to excessively low temperature in a low-temperature environment, ensuring the long-term stable operation of the dust collection system.

[0022] An impeller is coaxially mounted inside the telescopic cylinder 3. The impeller includes a hub and multiple blades 31 fixed circumferentially around the outer periphery of the hub. The blades 31 adopt an axial flow upward blade design, with the windward side of the blades 31 facing downwards from the telescopic cylinder 3 and the leeward side facing towards the guide cylinder 2. On one hand, the falling dry slag and swirling gas entering the telescopic cylinder 3 from the guide cylinder 2 through the slag discharge port impact the windward side of the blades 31, driving the impeller to rotate continuously. The driving force comes from the inherent slag flow and airflow during the slag discharge process itself. As long as slag discharge is in progress, the impeller will not stop rotating. On the other hand, when the impeller rotates, the leeward side of the blades 31 generates an upward airflow toward the guide tube 2. This upward airflow blows the fine dust that has not yet settled inside the telescopic tube 3 back into the area of ​​the guide tube 2, allowing the fine dust to re-enter the dust collection range of the first negative pressure dust collection unit of the negative pressure dust collection system. At the same time, the local low-pressure area formed by the leeward side of the blades 31 during rotation will also have a suction effect on the surrounding airflow, sucking in the dust-laden airflow near the wall of the telescopic tube 3 and transporting it upward.

[0023] A magnetic coupling inner magnetic ring 32 is embedded in the hub. The magnetic poles of the magnetic coupling inner magnetic ring 32 are arranged alternately in the circumferential direction. An annular rotor 33 is rotatably fitted on the outer wall of the telescopic cylinder 3 through a bearing. A magnetic coupling outer magnetic ring 34 is embedded in the inner wall of the annular rotor 33. The magnetic poles of the magnetic coupling outer magnetic ring 34 are arranged alternately in the circumferential direction and correspond one-to-one with the magnetic poles of the magnetic coupling inner magnetic ring 32. The annular rotor 33 and the impeller are driven by magnetic coupling, so that the annular rotor 33 rotates synchronously with the impeller. The advantage of magnetic coupling transmission is that the rotational torque of the impeller can be transmitted to the annular rotor 33 outside without contact through the pipe wall of the telescopic cylinder 3. It is not necessary to open any holes in the pipe wall or penetrate the shaft seal, thereby completely avoiding the risk of dust leakage from the transmission part. At the same time, the magnetic coupling itself does not produce mechanical wear, has a long service life, and requires little maintenance.

[0024] An annular stator 35 is fixed at the lower end of the slag discharge port. The annular stator 35 is sleeved on the outer periphery of the annular rotor 33. The inner wall of the annular stator 35 is covered with a first friction layer, which is made of polytetrafluoroethylene film or perfluoroethylene-propylene copolymer film. The outer wall of the annular rotor 33 is covered with a second friction layer, which is made of nylon film or aluminum foil. The first friction layer and the second friction layer maintain contact or micro-gap contact. When the annular rotor 33 rotates continuously with the impeller, the second friction layer continuously slides relative to the fixed first friction layer. Friction occurs when two different friction layers come into contact and separate, resulting in charge transfer. Polytetrafluoroethylene or perfluoroethylene-propylene copolymer has a strong affinity for electrons and easily gains electrons, becoming negatively charged. Nylon or aluminum foil has a weak affinity for electrons and easily loses electrons, becoming positively charged. As sliding friction continues, opposite charges accumulate on the surfaces of the two friction layers, forming a potential difference between the annular stator 35 and the annular rotor 33. This potential difference is transmitted to the rectifier and energy storage circuit through wires, and after rectification and energy storage, it is converted into usable direct current.

[0025] The output terminal of the rectifier energy storage circuit is connected to a conductive barb ring 37. The conductive barb ring 37 is fixedly installed on the inner wall surface of the telescopic cylinder 3. The conductive barb ring 37 includes an annular insulating base 36 and multiple conductive barbs 37 uniformly fixed on the annular insulating base 36 in the circumferential direction. The conductive barb 37 is a rigid conical metal body with its tip facing the inner wall of the telescopic cylinder 3 and maintaining a constant gap of 1 to 3 mm with the inner wall of the telescopic cylinder 3, without direct contact. The annular insulating substrate 36 is made of a radially elastic material. Its slight elastic deformation is used to absorb the mechanical vibration transmitted from the rapping assembly 5 to the barb ring and to compensate for the assembly error of the inner wall of the telescopic cylinder 3. It can form a non-uniform electric field region between the tip of the barb and the grounded inner wall of the telescopic cylinder 3. When high voltage is applied to the barb, the electric field strength near the tip is extremely high, which is enough to ionize the surrounding air and form a corona discharge, generating a large number of positive and negative ions. When the falling fine dust passes through this region, it collides with the ions and becomes charged. The charged fine dust migrates to the grounded inner wall of the telescopic cylinder 3 under the action of electric field force and is captured on the wall surface, thereby achieving the purpose of electrostatic dust removal and avoiding dust. Then the fine dust adsorbed on the wall surface is further cleaned and discharged. It should be noted that the electrostatic dust removal and the rapping component 5 do not work simultaneously, but rather work in sequence according to the slag discharge process. During the slag discharge process, the dry slag continues to fall, the impeller continues to rotate, and the conductive barbs 37 ring continuously generate corona discharge. After being charged, the fine ash continuously migrates to the inner wall of the telescopic cylinder 3 and is adsorbed onto the wall surface. At this time, the rapping component 5 maintains low-frequency operation or stops operation to avoid the mechanical vibration generated by the rapping interfering with the normal adsorption process of the fine ash on the wall surface, and at the same time avoids the rapping shaking off the unstable ash layer too early, causing secondary dust. When the slag discharge is completed and all the dry slag is discharged into the slag truck hopper, the telescopic cylinder 3 rises and resets under the drive of the vertical deformation mechanism, and the annular elastic sealing ring 41 disengages from the hopper. At this time, the negative pressure dust collection system continues to operate, and the first negative pressure dust collection unit and the second negative pressure dust collection unit continue to suck up, maintaining a negative pressure environment inside and around the guide cylinder 2 and the telescopic cylinder 3. Then, the rapping component 5 starts high-frequency rapping to shake off the fine ash layer adsorbed and accumulated on the inner wall surface of the telescopic cylinder 3 during the slag discharge process. The shaken-off fine ash is sucked into the negative pressure dust collection system under the influence of the negative pressure airflow and discharged after being purified by the dust collector.

[0026] If the tip of the barb comes into direct contact with the inner wall, a short circuit will be formed, and corona discharge cannot be generated. Therefore, maintaining a gap is necessary. The length of the conductive barb 37 is controlled between 3 and 8 mm, and the spacing between adjacent barbs is controlled between 2 and 5 mm. This size range takes into account both discharge intensity and processing feasibility. If the barb is too short, the discharge area will be small and the dust removal efficiency will be low. If the barb is too long, it will be easy to deform under the impact of airflow, resulting in unstable gap. If the spacing is too large, a discharge blind zone will appear. If the spacing is too small, the adjacent barbs will shield each other, which will reduce the discharge efficiency.

[0027] The cross-section of the annular insulating substrate 36 is wedge-shaped, and its upper surface is an inwardly inclined slope. The annular insulating substrate 36 is located on the inner wall of the telescopic cylinder 3 and will inevitably come into contact with the dust-laden airflow. If the upper surface of the substrate is flat, dust will easily accumulate after falling on it, and over time a dust layer will form. The dust layer may affect the positioning accuracy of the barbs, and may also cause a decrease in insulation performance due to the absorption of moisture by the dust, or even cause high voltage leakage or creepage. The wedge-shaped slope allows the dust falling on it to slide off naturally under the action of gravity. The dust-repellent coating further reduces the adhesion between the dust and the substrate surface. Even if a small amount of dust is attached, it is easily blown away by the airflow, thereby maintaining the cleanliness of the substrate surface and the stability of the insulation performance. The telescopic cylinder 3 is connected to the ground via a grounding wire, providing a grounded electrode for electrostatic dust removal. At the same time, it unifies the potential reference of the triboelectric nanogenerator and the electrostatic dust removal system to the ground potential, ensuring the safety of personnel and equipment.

[0028] The cyclone separation chamber includes a cylindrical section and a conical section. The air inlet 22 and the spiral guide rib 21 are opened on the side wall of the cylindrical section. The cross section of the spiral guide rib 21 is trapezoidal and the pitch gradually decreases from top to bottom. This gradually changing pitch design makes the rotation speed of the airflow gradually increase during the downward flow, and the centrifugal separation effect is continuously enhanced. Fine ash is more fully separated into the central area, while coarse slag slides down the wall under the combined action of centrifugal force and gravity. The bottom opening of the conical section connects to the slag discharge port, and the inner wall of the conical section is covered with a ceramic wear-resistant coating. This is because the conical section is the area where coarse slag falls in concentrated form. The high-speed rotating coarse slag particles cause severe scouring and wear on the wall surface. The ceramic coating has high hardness and high wear resistance, which can significantly extend the service life of the cyclone separator. At the same time, the smooth ceramic surface is not easy to adhere to slag accumulation, which is also conducive to keeping the flow channel of the cyclone separator unobstructed.

[0029] Preferably, the spiral guide rib 21 is made of thermally conductive material, and a cooling channel is formed inside it along the length of the rib. The cooling channel is connected to the cooling medium circulation loop of the cooling coil 23 through a rotary joint. Specifically, the spiral guide rib 21 is made of ceramic matrix composite material or ceramic-filled engineering plastic, and a cooling channel is opened inside it along the length of the rib. The cooling channel is connected to the cooling medium circulation loop of the cooling coil 23 through a rotary joint.

[0030] The material selection for the spiral guide rib 21 has two considerations: First, the material needs to have a moderate thermal conductivity so that the cooling medium in the cooling channel can reduce the rib surface temperature to a level lower than the airflow temperature at the center of the guide tube 2, and form a radial temperature gradient pointing towards the rib surface in the normal direction of the rib surface, providing a driving force for the thermophoresis effect. At the same time, the moderate thermal conductivity avoids excessive homogenization of the rib surface temperature or condensation caused by the temperature falling below the airflow dew point. Second, the material itself or the surface coating needs to have a high dielectric constant (greater than 10) to meet the requirements of the dielectric electrophoresis effect for the establishment of an insulating electric field.

[0031] The cooling medium supplied by the cooling medium supply pump 24 to the cooling channel inside the spiral guide rib 21 has a temperature that makes the rib surface temperature of the spiral guide rib 21 lower than the central airflow temperature of the guide cylinder 2, forming a radial temperature gradient pointing towards the rib surface in the normal direction of the rib surface of the spiral guide rib 21.

[0032] The basic principle of thermophoresis is that when suspended particles are in a gas with a temperature gradient, the average kinetic energy of gas molecules on the high-temperature side is greater than that on the low-temperature side. The collision momentum of the particles from the gas molecules on the high-temperature side is greater than that on the low-temperature side, thus generating a net force from the high-temperature region to the low-temperature region, which is the thermophoretic force. For micron-sized and submicron-sized fine dust particles, the thermophoretic force is sufficient to cause them to migrate in a directional manner in the temperature gradient field.

[0033] In this device, the high-temperature dry slag keeps the central airflow of the guide tube 2 at a high temperature, while the spiral guide rib 21 has a significantly lower rib surface temperature than the central airflow temperature due to the continuous cooling of the internal cooling channel. Therefore, a stable radial temperature gradient is formed in the normal direction of the rib surface of the spiral guide rib 21. When the dust-laden airflow flows downward along the spiral channel of the spiral guide rib 21, the fine dust particles migrate directionally to the lower temperature rib surface of the spiral guide rib 21 under the action of thermophoretic force and are deposited on the rib surface, thus realizing the passive separation of fine dust and airflow. Thermophoretic separation does not require any external energy and is driven entirely by the temperature difference created by the cooling coil 23, and has a high collection efficiency for micron-sized fine dust.

[0034] The fine ash deposited on the surface of the spiral guide rib 21 continues to accumulate during the slag discharge process. After the slag discharge is completed and all the dry slag is discharged into the slag truck hopper, the rapping component 5 starts high-frequency rapping to shake off the fine ash layer deposited on the surface of the spiral guide rib 21 and discharge it.

[0035] The pitch of the spiral guide rib 21 gradually decreases from top to bottom, causing the airflow rotation speed to gradually increase downwards. The thermophoretic force and centrifugal force are superimposed radially, meaning the centrifugal force pushes particles towards the outer wall, while the thermophoretic force pulls particles towards the low-temperature rib surface. Together, they push fine ash towards the wall and rib surfaces of the guide tube 2, further improving the separation efficiency of fine ash. This design reverses the thermophoretic effect, usually considered the culprit for ash accumulation on the heat exchanger surface, and utilizes it as an effective means of fine ash separation. By integrating the cooling channel inside the spiral guide rib 21, the spiral guide rib 21 simultaneously possesses three functions: flow guidance, heat exchange, and thermophoretic settling. This achieves enhanced separation of fine ash within the cyclone separation chamber without adding extra moving parts or external energy.

[0036] As a preferred embodiment, the rib surface of the spiral flow guide rib 21 is covered with a dielectric coating, the relative permittivity of which is greater than 10; the output terminal of the rectifier energy storage circuit is also connected to the rib surface of the spiral flow guide rib 21 via a high-voltage wire, so that a non-uniform electric field is formed between the rib surface of the spiral flow guide rib 21 and the grounded wall surface of the flow guide cylinder 2; the pitch of the spiral flow guide rib 21 gradually decreases from top to bottom, so that the temperature gradient field at the upper part of the flow guide cylinder 2 is stronger than the electric field strength, and the non-uniformity of the electric field at the lower part of the flow guide cylinder 2 is stronger than the temperature gradient. When the dust-laden airflow flows downward along the spiral channel of the spiral guide rib 21, under the combined action of the temperature gradient field and the electric field gradient field, the fine dust particles are simultaneously subjected to thermophoretic force and dielectric force, and the directions of both forces are pointing towards the rib surface of the spiral guide rib 21. The thermophoretic force is proportional to the first power of the particle diameter, while the viscous drag force is proportional to the square of the diameter. Therefore, the ratio of thermophoretic force to drag force is greater for submicron-sized fine ash particles, resulting in a more significant thermophoretic deposition effect. The dielectric force is proportional to the cube of the particle diameter. Therefore, the dielectric force is relatively stronger for micron-sized fine ash particles, resulting in a more significant electrophoretic deposition effect. In the upper region of the guide tube 2, the temperature gradient dominates, and submicron fine ash migrates and deposits towards the low-temperature rib surface under the dominance of thermophoretic force; in the lower region of the guide tube 2, the electric field non-uniformity dominates, and micron fine ash migrates and deposits towards the high electric field strength rib surface under the dominance of dielectric force; the two physical fields each dominate in different particle size ranges and cooperate with each other, so that fine ash in the entire particle size range is guided to be deposited on the rib surface, and the deposited fine ash is shaken off by the rapping component 5 and flows into the coarse slag for discharge.

[0037] Specifically, the decreasing pitch of the spiral guide ribs 21 causes the airflow rotation speed to gradually increase downwards, and the centrifugal force to gradually strengthen. On the other hand, the decreasing pitch causes the curvature of the spiral guide ribs 21 to gradually increase downwards, forming a natural non-uniform electric field region at the rib tips and edges, where the electric field strength reaches its maximum value, and the dielectric force also reaches its maximum value. More importantly, the design of the gradually decreasing pitch from top to bottom creates two regions with different physical field characteristics inside the guide tube 2. In the upper region of the guide tube 2, the rib spacing is larger, the airflow rotation speed is slower, and the temperature gradient field is relatively stronger, guiding submicron fine dust to be deposited on the low-temperature rib surface under the dominant effect of thermophoretic force. In the lower region of the guide tube 2, the rib spacing is smaller, the airflow rotation speed is faster, and the non-uniformity of the electric field at the rib tips is significantly enhanced, guiding micron fine dust to be deposited in the high electric field intensity rib tip region under the dominant effect of dielectric force.

[0038] The negative pressure dust collection system includes a first negative pressure dust collection unit and a second negative pressure dust collection unit. The first negative pressure dust collection unit is located on the outer periphery of the guide tube 2. The first negative pressure dust collection unit includes a first dust collector 51 and a first negative pressure fan 52. The first dust collector 51 is connected to the negative pressure suction port 53 provided on the guide tube 2. The first dust collector 51 is connected to the first negative pressure fan 52. The first negative pressure fan 52 keeps running during the slag discharge process. It continuously extracts the fine dust that has accumulated in the central area after cyclone separation in the guide tube 2 through the negative pressure suction port 53, completing the first-stage primary adsorption dust removal. The suction force of this stage is designed to be relatively mild. The main purpose is to first suck away most of the suspended fine dust in the airflow to prevent it from continuing to diffuse downstream. At the same time, the mild suction force will not interfere with the airflow organization in the cyclone separation chamber and the normal falling of the dry slag. The second negative pressure dust collection unit includes a second dust suction hood 54, a second dust collector 55, and a second negative pressure fan 56. The second dust suction hood 54 is arranged around the lower outer periphery of the annular elastic sealing ring 41. The second dust suction hood 54 is connected to the second dust collector 55, and the second dust collector 55 is connected to the second negative pressure fan 56. The second negative pressure fan 56 has two suction power settings. The first suction power is equivalent to or slightly greater than that of the first negative pressure fan 52, while the second suction power is much greater than that of the first negative pressure fan 52. This design is based on the consideration that if it operates at the second high suction power from the beginning, the strong negative pressure will suck the unstable dry slag and fine dust in the truck bed into the dust collection system through the gap between the sealing ring and the truck bed. This will not only increase the burden on the dust collector but may also disrupt the normal accumulation process of the dry slag. Therefore, in the early and middle stages of slag discharge, the second negative pressure dust collection unit only operates at the first setting. At this time, its main function is to assist the electrostatic dust removal system in removing the small amount of fine dust that has escaped from the periphery of the sealing ring. The suction unit works in synergy with the electrostatic precipitator. The electrostatic precipitator charges the fine dust in the airflow inside the telescopic cylinder 3 and adsorbs it onto the wall surface. The second negative pressure dust collection unit is responsible for capturing any fine dust that may escape. When the slag discharge is completed and all the dry slag is discharged into the slag truck hopper, the annular elastic sealing ring 41 disengages from the hopper. At this time, the second negative pressure dust collection unit switches to the second gear and operates with high suction power. At the same time, the rapping component 5 starts high-frequency rapping to shake off the fine dust layer that was adsorbed and accumulated on the inner wall surface of the telescopic cylinder 3 during the slag discharge process. The fine dust that is shaken off is directly sucked into the second dust collector 55 for purification under the strong negative pressure airflow of the second negative pressure dust collection unit, instead of being allowed to drift into the environment. This phased and geared operation strategy ensures the continuity and efficiency of dust removal during the slag discharge process and avoids the interference of excessive negative pressure on the normal slag discharge process. The outlets of the first negative pressure fan 52 and the second negative pressure fan 56 are connected to the same instrument compressed air source.

[0039] The vertical deformation mechanism includes at least two circumferentially evenly distributed electric push rods 6 and a pressure-sensitive trigger switch. The cylinder end of each electric push rod 6 is fixed to the lower end face of the slag discharge port, and the push rod end of each electric push rod 6 extends vertically downward and is fixedly connected to the lower end of the telescopic cylinder 3. Compared with springs or cylinders, the electric push rod 6 has the advantage that the extension and retraction amount and thrust of the push rod can be precisely controlled, and it has a self-locking ability after power failure, and will not drift due to gravity or external force. This is especially important for slag discharge conditions that require maintaining a fixed position for a long time. The pressure-sensitive trigger switch is installed on the bottom surface of the annular elastic sealing ring 41 and is electrically connected to the control end of each electric push rod 6. When the pressure-sensitive trigger switch detects the bottom... When the pressure is lower than the first preset threshold, it indicates that the contact pressure between the annular elastic sealing ring 41 and the dump truck hopper or the material surface is insufficient, resulting in a gap for ash leakage. At this time, the push rods of each electric push rod 6 are controlled to extend synchronously, pushing the telescopic cylinder 3 to extend downward, so that the annular elastic sealing ring 41 descends to fit the edge of the dump truck hopper or the material surface. When the pressure sensor trigger switch detects that the bottom pressure is higher than the second preset threshold, it indicates that the annular elastic sealing ring 41 is over-compressed. At this time, the push rods of each electric push rod 6 are controlled to retract synchronously, so that the telescopic cylinder 3 shortens upward, and the annular elastic sealing ring 41 rises and detaches from the edge of the dump truck hopper or the material surface, thereby preventing the sealing ring from aging or deforming due to prolonged excessive pressure. It should be noted that the extension and retraction of the electric push rod 6 is not a frequent start-stop operation. Instead, it is adjusted to the correct position once before the slag discharge begins, and then minor adjustments are made during the slag discharge process based on the height changes caused by material accumulation. These adjustments are typically only a few millimeters to tens of millimeters in size and occur at a very low frequency. Therefore, the power consumption and wear of the electric push rod 6 are very low, resulting in a long service life. The annular elastic sealing ring 41 is made of elastic rubber or elastic fabric. The lower end of the annular elastic sealing ring 41 hangs down naturally, forming a free end. In its natural state, the annular elastic sealing ring 41 remains in a contracted state, and the inner diameter of its lower free end is smaller than the outer diameter of the slag truck hopper. The cylinder wall of the annular elastic sealing ring 41 has multiple pleats evenly arranged circumferentially. These pleats give the annular elastic sealing ring 41 the ability to expand elastically in both the radial and circumferential directions. When the telescopic cylinder 3 descends and the free end of the annular elastic sealing ring 41 contacts the edge of the hopper or the material surface, the free end expands elastically in the radial direction under the contact pressure. The folds unfold, allowing the annular elastic sealing ring 41 to fit tightly against the contact surface. As material continues to accumulate and the pushing force increases, the annular elastic sealing ring 41 further expands to accommodate a larger contact surface. Simultaneously, the vertical deformation mechanism slightly raises the telescopic cylinder 3 based on the signal from the pressure-sensing trigger switch, preventing the sealing ring from being buried by material or overstretched. When the slag discharge ends and the telescopic cylinder 3 rises and resets, the annular elastic sealing ring 41 automatically retracts back to its original size and shape under the guidance of its own elastic restoring force, preparing for the next slag discharge cycle. This design does not require a complex radial drive mechanism, nor does it require a motor or connecting rod to control the expansion and contraction of the annular elastic sealing ring 41. It relies entirely on the elasticity of the material itself and the guiding effect of the folds to achieve self-adaptive sealing. The structure is simple, highly reliable, and has low maintenance costs. At the same time, the fold structure also increases the axial stiffness of the annular elastic sealing ring 41, preventing it from easily flipping or twisting when pushed by material, thus maintaining a good sealing posture.

[0040] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A dust prevention device for a dry ash discharge system in a thermal power plant, characterized in that: The system includes a guide tube (2) positioned between the slag bin (1) and the slag discharge port, a telescopic tube (3) installed at the bottom of the slag discharge port, a sealing base (4) connected to the lower end of the telescopic tube (3) and capable of telescopic extension and retraction in the vertical direction, and a vibrating assembly (5) fixed to the outside of the guide tube (2) and the telescopic tube (3); the sealing base (4) is positioned between the lower end of the telescopic tube (3) and the slag truck hopper, and the sealing base (4) includes an annular elastic sealing ring (41) connected to the telescopic tube (3) and a vertical deformation mechanism for controlling the vertical contraction of the telescopic tube (3); it also includes a negative pressure dust collection system, which is used to collect dust generated during the slag discharge process; The guide tube (2) is equipped with a cyclone separation chamber. Multiple spiral guide ribs (21) are evenly distributed along the circumference of the inner wall of the cyclone separation chamber. Multiple air inlets (22) are tangentially opened on the side wall of the cyclone separation chamber. The air inlets (22) are connected to a high-pressure air source. The outer wall of the guide tube (2) is wrapped with a cooling coil (23). Cooling medium flows inside the cooling coil (23). The inlet of the cooling coil (23) is connected to a cooling medium supply pump (24). The outlet of the cooling coil (23) is connected to a heat exchanger (25). The other end of the heat exchanger (25) is connected to the pipeline of the negative pressure dust collection system for preheating the airflow entering the negative pressure dust collection system.

2. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: An impeller is coaxially arranged inside the telescopic cylinder (3). The impeller includes a hub and multiple blades (31) fixed circumferentially to the outer periphery of the hub. The windward side of the blades (31) faces the lower part of the telescopic cylinder (3), and the leeward side of the blades (31) faces the direction of the guide cylinder (2). A magnetic coupling inner magnetic ring (32) is embedded in the hub, and the magnetic poles of the magnetic coupling inner magnetic ring (32) are alternately arranged circumferentially. An annular rotor (33) is rotatably fitted on the outer wall of the telescopic cylinder (3) through a bearing. A magnetic coupling outer magnetic ring (34) is embedded in the inner wall of the annular rotor (33), and the magnetic poles of the magnetic coupling outer magnetic ring (34) are alternately arranged circumferentially and correspond one-to-one with the magnetic poles of the magnetic coupling inner magnetic ring (32). The annular rotor (33) and the inner wall of the hub are coaxially arranged with the outer wall of the telescopic cylinder (3). The impeller is driven by magnetic coupling, causing the annular rotor (33) to rotate synchronously with the impeller; an annular stator (35) is fixed at the lower end of the slag discharge port, and the annular stator (35) is sleeved on the outer periphery of the annular rotor (33); the inner wall of the annular stator (35) is covered with a first friction layer, which is a polytetrafluoroethylene film or a perfluoroethylene propylene copolymer film; the outer wall of the annular rotor (33) is covered with a second friction layer, which is a nylon film or aluminum foil; the first friction layer and the second friction layer are in contact or in micro-gap contact; the annular stator (35) and the annular rotor (33) are respectively connected to a rectifier energy storage circuit through wires, and the output end of the rectifier energy storage circuit is connected to a conductive barbed ring.

3. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 2, characterized in that: The conductive barb ring is fixedly installed on the inner wall of the telescopic cylinder (3). The conductive barb ring includes an annular insulating base (36) and multiple conductive barbs (37) uniformly fixed on the annular insulating base (36) along the circumference. The tips of the conductive barbs (37) face the inner wall of the telescopic cylinder (3). The cross-section of the annular insulating base (36) is wedge-shaped, and its upper surface is an inwardly inclined slope covered with a dust-repellent coating. The telescopic cylinder (3) is connected to the ground through a grounding wire.

4. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: The cyclone separation chamber includes a cylindrical section and a conical section. An air inlet (22) and a spiral guide rib (21) are opened on the side wall of the cylindrical section. The cross section of the spiral guide rib (21) is trapezoidal and the pitch gradually decreases from top to bottom. The bottom opening of the conical section is connected to the slag discharge port, and the inner wall of the conical section is covered with a ceramic wear-resistant coating.

5. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: The negative pressure dust collection system includes a first negative pressure dust collection unit and a second negative pressure dust collection unit. The first negative pressure dust collection unit is located on the outer periphery of the guide tube (2). The first negative pressure dust collection unit includes a first dust collector (51) and a first negative pressure fan (52). The first dust collector (51) is connected to the negative pressure suction port (53) provided on the guide tube (2). The first dust collector (51) is connected to the first negative pressure fan (52). The second negative pressure dust collection unit includes a dust suction hood (54), a second dust collector (55), and a second negative pressure fan (56). The second dust suction hood (54) is arranged around the lower periphery of the annular elastic sealing ring (41). The second dust suction hood (54) is connected to the second dust collector (55). The second dust collector (55) is connected to the second negative pressure fan (56). The outlets of the first negative pressure fan (52) and the second negative pressure fan (56) are connected to the same instrument compressed air source.

6. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: The vertical deformation mechanism includes at least two electric push rods (6) evenly distributed circumferentially and a pressure-sensitive trigger switch; the cylinder end of each electric push rod (6) is fixed to the lower end face of the slag discharge port, and the push rod end of each electric push rod (6) extends vertically downward and is fixedly connected to the lower end of the telescopic cylinder (3); the pressure-sensitive trigger switch is installed on the bottom surface of the annular elastic sealing ring (41) and electrically connected to the control end of each electric push rod (6); when the pressure-sensitive trigger switch detects that the bottom pressure is lower than the first preset threshold, it controls the push rod of each electric push rod (6) to drive the annular elastic sealing ring (41) to descend to fit the edge of the slag truck bucket; when the pressure-sensitive trigger switch detects that the bottom pressure is higher than the second preset threshold, it controls the push rod of each electric push rod (6) to retract synchronously, so that the annular elastic sealing ring (41) rises and disengages from the edge of the slag truck bucket.

7. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: The annular elastic sealing ring (41) is made of elastic rubber or elastic fabric. The lower end of the annular elastic sealing ring (41) hangs down naturally to form a free end. The annular elastic sealing ring (41) remains in a contracted state in its natural state. The cylindrical wall of the annular elastic sealing ring (41) is uniformly provided with multiple folds along the circumference, so that the annular elastic sealing ring (41) has the ability to expand elastically in the radial and circumferential directions.

8. A dust control device for a dry ash discharge system in a thermal power plant as described in claim 1, characterized in that: The spiral guide rib (21) is made of thermally conductive material and has a cooling channel inside along the length of the rib. The cooling channel is connected to the cooling medium circulation loop of the cooling coil (23) through a rotary joint. The cooling medium supplied by the cooling medium supply pump (24) to the cooling channel inside the spiral guide rib (21) is so that the rib surface temperature of the spiral guide rib (21) is lower than the central airflow temperature of the guide tube (2), forming a radial temperature gradient pointing towards the rib surface in the normal direction of the rib surface of the spiral guide rib (21).

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