Fly ash dioxin removal device and method

Abstract

The application discloses a fly ash dioxin removal device and method, relates to the technical field of fly ash treatment, and solves the problems of low removal efficiency, complicated process and high cost in the process of removing dioxin in fly ash. The system comprises an air duct for introducing high-temperature flue gas, a circulating desorption device and a secondary air duct, a first temperature sensor installed in the air duct, a fan, a second temperature sensor and a particulate matter detector installed in the secondary air duct, and a controller. The system can utilize the high-temperature flue gas of the incinerator in the existing garbage incineration process to perform cyclic desorption on dioxin in fly ash, greatly improves the desorption effect of dioxin in fly ash, mixes the desorbed dioxin with air to return to the incinerator for high-temperature oxidation, and ingeniously utilizes the existing garbage incineration process, fully utilizes online production conditions, has no secondary large energy input, and thus effectively reduces the cost.

Description

Technical Field

[0001] This application relates to the field of fly ash treatment technology, and in particular to a fly ash dioxin removal device and method. Background Technology

[0002] Fly ash is a substance containing various pollutants, typically collected by baghouse dust collectors after a series of treatments following high-temperature incineration. Source industries include waste incineration and hazardous waste incineration. For example, in the waste incineration industry: with the increasing prevalence of municipal solid waste incineration, my country's fly ash production is also continuously increasing. Fly ash has a complex composition, adsorbing high concentrations of organic and inorganic pollutants from flue gas. In particular, fly ash contains highly carcinogenic, teratogenic, and mutagenic dioxins and heavy metals. If not properly treated, these pollutants will be transported from the emission source to various locations through the atmosphere and rainwater, polluting the air and water sources, entering the food chain, and causing harm to humans. Therefore, achieving the harmless disposal and resource utilization of fly ash is one of the urgent environmental problems that needs to be solved.

[0003] Currently, the main technologies for treating dioxins in fly ash include solidification and landfill, biodegradation, chemical removal, low-temperature pyrolysis, and high-temperature treatment. Among these, solidification and landfill may become a potential source of dioxin pollution for landfills; biodegradation and low-temperature pyrolysis have the advantages of being environmentally friendly and low-cost, but their dioxin degradation efficiency is not high; chemical removal has the advantages of low energy consumption and high efficiency, but it poses the problem of secondary pollution. Co-processing fly ash in cement kilns is currently the mainstream high-temperature treatment technology. To strictly control the chlorine content, the amount of fly ash adulterated is very low; therefore, cement kilns can only achieve limited resource utilization of fly ash.

[0004] In addition, water washing is also common, but this process removes less dioxins. Studies have found that the highest toxicity equivalent in ash washing wastewater is 2,3,7,8-TCDD, accounting for 33.93% of the total toxicity equivalent in ash washing wastewater. The migration rate from raw ash to ash washing wastewater is only 0.26%, so this method cannot effectively remove dioxins.

[0005] Existing dioxin removal processes often require high-temperature desorption and re-oxidation using equipment, or the use of inert gases for high-temperature desorption. Both of these require the introduction of third-party equipment and processes, making the processes cumbersome, difficult to operate, and increasing the cost of dioxin removal and treatment.

[0006] For example, the patent with publication number TW200736549A, titled "Treatment Equipment and Method for Degrading Dioxin-like Compounds by Medium-Temperature Desorption Combined with High-Temperature Plasma Oxidation," uses a temperature between 450-850℃ for desorption. The desorbed gas then enters a high-temperature plasma oxidation chamber at at least 1200℃, where a plasma torch oxidizes and destroys the dioxin-like compounds in the gas stream—a process known as plasma torching. The gas is then discharged after passing through a quench tower, a lime reaction tower, an activated carbon injection device, and a filter bag dust collector. Summary of the Invention

[0007] The purpose of this application is to overcome the problems of low removal efficiency, complicated process and high cost in the existing technology for removing dioxins from fly ash, and to provide a fly ash dioxin removal device and method.

[0008] In a first aspect, a fly ash dioxin removal device is provided, comprising an exhaust duct with a temperature regulating component, one end of the exhaust duct being connected to an incineration system, and the other end of the exhaust duct being connected to a circulating desorption device, the flue gas outlet of the circulating desorption device being connected to a secondary air duct of the incinerator through a second air duct, a first temperature sensor being installed inside the circulating desorption device, a fan being installed in the exhaust duct, a second temperature sensor and a particulate matter detector being installed in the second air duct, and the first temperature sensor, the fan, the second temperature sensor and the particulate matter detector being electrically connected to a controller;

[0009] The circulating desorption device includes a housing, with a base hinged to the lower end of the housing. A hydraulic cylinder is hinged to the base, and the piston rod of the hydraulic cylinder is hinged to the housing. One end of the housing has a fly ash inlet and a flue gas outlet, with the flue gas outlet connected to the secondary air duct of the incinerator via a second air duct. The bottom of the other end of the housing has a fly ash outlet. A rotatable drum is installed inside the housing, with accumulation plates densely distributed on its inner wall. A mesh cylinder is fixed inside the drum via several first connecting rods, and a auger blade is fixed inside the mesh cylinder via second connecting rods. The end of the auger blade near the fly ash outlet is rotatably connected to the housing. A conveying cylinder is fitted around the auger blade and is fixedly connected to the housing. The conveying cylinder has a feed port at one end near the fly ash discharge port and a discharge port at the other end. An annular air outlet is fixedly fitted on the outside of the conveying cylinder near the feed port. The annular air outlet is connected to a flue gas inlet, which is connected to an exhaust pipe. A first baffle is hinged inside the shell at one end near the fly ash discharge port, and a second baffle is hinged on the inner wall of the shell at one end near the fly ash feed port. Both the first and second baffles are connected to a power source. A gear ring is fixedly fitted on the outer wall of the drum. A motor is fixed on the outer wall of the shell. A gear meshing with the gear ring is installed on the shaft of the motor. The hydraulic controller, motor, and power source of the hydraulic cylinder are all electrically connected to the controller.

[0010] In some possible implementations, the incineration system includes an incinerator, a primary waste heat recovery device, and a secondary waste heat recovery device. The induced draft duct includes a first duct, one end of which is connected to the flue gas inlet of the circulating desorption device, and the other end of which is connected to a first branch duct and a second branch duct. The first branch duct is used to connect the pipeline between the incinerator and the primary waste heat recovery device, and the second branch duct is used to connect the pipeline between the primary waste heat recovery device and the secondary waste heat recovery device. The temperature control component includes a first air valve and a second air valve, the first air valve being installed in the first branch duct and the second air valve being installed in the second branch duct.

[0011] In some possible implementations, the number of circulating desorption devices is set to at least two and the circulating desorption devices are arranged in parallel. The first air valve and the second air valve are both electrically controlled valves and are electrically connected to the controller. Because the circulating desorption device of this application needs to stop feeding fly ash after a certain amount of fly ash is fed into the circulating desorption device, and fly ash can only be fed again after the desorbed fly ash is discharged after a certain amount of fly ash has been circulated and desorbed, the fly ash processing is intermittent. By setting at least two circulating desorption devices in parallel, when one of them is in the state of circulating desorption and cannot feed fly ash, the other pair of circulating desorption devices can feed fly ash and perform circulating desorption of fly ash, thereby ensuring the continuous operation of fly ash processing. Secondly, by setting the first air valve and the second air valve as electrically controlled valves, the first air valve and the second air valve can be automatically controlled according to the temperature data inside the circulating desorption device detected by the first temperature sensor.

[0012] In some possible implementations, the fly ash inlet of the circulating desorption device is connected to the output end of a rotary feeder, the input end of which is used to connect to an ash source, and the rotary feeder is electrically connected to a controller. The rotary feeder is used to feed fly ash from the ash source (e.g., a transfer ash silo) into the circulating desorption device.

[0013] In some possible implementations, the housing includes an inner housing and an outer housing, with an auxiliary heating space reserved between the inner housing and the outer housing. The auxiliary heating space is provided with an auxiliary heating air inlet and an auxiliary heating air outlet. The first temperature sensor is installed on the inner wall of the inner housing. By introducing high-temperature flue gas into the auxiliary heating space between the inner housing and the outer housing, the heat preservation effect of the circulating desorption device can be achieved, which helps to maintain the desorption environment in the circulating desorption device within the temperature range of 650℃-750℃, thereby further improving the desorption effect.

[0014] In some possible implementations, a material level sensor is installed inside the inner shell, and a space for installing a roller is reserved in the middle of the inner shell. A first limiting ring is fixedly sleeved on the outer wall of both ends of the roller, and a second limiting ring that cooperates with the first limiting ring is fixed inside both ends of the inner shell. The material level sensor is electrically connected to the controller. The material level sensor can detect the amount of fly ash in the circulating desorption device in real time. Based on the amount of fly ash, the feeding of fly ash can be automatically controlled. When the amount of fly ash in the circulating desorption device reaches a preset value, the feeding of fly ash will automatically stop. Furthermore, the mutual limiting effect of the first and second limiting rings allows the roller to rotate freely without deviation. At the same time, the first and second limiting rings can also play a sealing role to minimize the leakage of flue gas in the circulating desorption device.

[0015] In some possible implementations, a dust baffle is installed on the inner wall of the housing near the flue gas outlet. The dust baffle is installed directly below the flue gas outlet and a certain distance is reserved between them so that the flue gas cannot enter the flue gas outlet in a straight line, but instead detours around the sides of the dust baffle to the flue gas outlet and is discharged, thereby minimizing the fly ash content in the flue gas output from the flue gas outlet.

[0016] In a second aspect, a method for removing dioxins from fly ash is provided, applied to the apparatus described in the first aspect, the method comprising:

[0017] Start the fan and adjust the opening of the first and second air valves according to the detection data of the first temperature sensor to adjust the temperature in the circulating desorption device to 650℃-750℃.

[0018] Start the star feeder and control the ash feeding rate of the star feeder according to the amount of fly ash detected by the material level sensor;

[0019] The motor speed is adjusted according to the detection data of the particulate matter detector so that the flue gas output from the flue gas outlet carries a preset amount of fly ash.

[0020] Adjust the opening of the first and second valves according to the detection data of the second temperature sensor to regulate the flue gas temperature in the second duct to no less than 550℃.

[0021] In some possible implementations, the rotational speed of the drum and the angle of the shell are adjusted according to the physical properties of the fly ash so that the material accumulation plate on the inner wall of the drum can feed the fly ash at the bottom of the drum to the top of the drum and then drop it. The rotational speed of the drum is 10 r / min-100 r / min, the tilt angle of the shell is 5°-87°, and the aperture of the mesh cylinder is 1 cm-10 cm.

[0022] In some possible implementations, the air volume in the first duct is 1000m³. 3 / h-5000m 3 The ash feeding rate of the star feeder is 1.2t / h-1.6t / h, the reaction time between flue gas and fly ash in the circulating desorption device is 15min-90min, and the amount of fly ash carried in the flue gas output from the flue gas outlet is 5%-10% of the original fly ash amount.

[0023] This application has the following beneficial effects:

[0024] 1. The system of this application can be organically combined with the existing waste incineration system. It utilizes the high-temperature flue gas of the incinerator in the existing waste incineration process to desorb dioxins from fly ash, and then mixes the desorbed dioxins with air and returns them to the furnace for high-temperature oxidation. It cleverly utilizes the existing waste incineration process, makes full use of online production conditions, and has no secondary large energy input, thereby effectively reducing costs.

[0025] 2. By setting up a circulating desorption device, this application can use the auger blades to circulate and transport the fly ash at the bottom to the other end, and use the material accumulation plate on the inner wall of the drum to carry the fly ash at the bottom of the drum to a high place and then drop it down, so that the fly ash collides with the screen cylinder to achieve the crushing of large particles of fly ash. At the same time, the fly ash can fully contact and react with the high-temperature flue gas blown out of the annular exhaust duct, achieving efficient desorption of dioxins in the fly ash. In addition, the flue gas blown out of the annular exhaust duct can also play a back-flushing role to prevent fly ash from accumulating and clogging at the screen cylinder.

[0026] 3. The method of this application can automatically control the corresponding valve opening, the ash feeding rate of the rotary feeder, the tilt angle of the circulating desorption device, and the rotation speed of the drum and auger blades based on the detection data of the first temperature sensor, the second temperature sensor, and the particulate matter detector. This achieves automated control of the fly ash dioxin removal device, greatly simplifies the control process, and effectively ensures the desorption rate of dioxins in fly ash by controlling the fly ash desorption temperature within the range of 650℃-750℃, thereby improving the dioxin removal efficiency in fly ash. Furthermore, it can transport most of the incompletely desorbed dioxins back to the incinerator through the second air duct with an internal temperature of not less than 550℃, effectively avoiding dioxin regeneration and eliminating secondary pollution. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a structural block diagram of the fly ash dioxin removal device of Embodiment 1 of this application;

[0030] Figure 2 This is a structural block diagram of an existing waste incineration system;

[0031] Figure 3 This is a circuit block diagram of the fly ash dioxin removal device of Embodiment 1 of this application;

[0032] Figure 4 This is a model diagram of the type I adsorption isotherm of dioxins in fly ash;

[0033] Figure 5 This is a type I adsorption isobaric model diagram of dioxins in fly ash;

[0034] Figure 6 This is a schematic diagram of the circulating desorption device in the fly ash dioxin removal device of Embodiment 1 of this application;

[0035] Figure 7 This is a front view of the circulating desorption device in the fly ash dioxin removal device of Embodiment 1 of this application;

[0036] Figure 8 This is a cross-sectional view of the circulating desorption device in the fly ash dioxin removal device of Embodiment 1 of this application;

[0037] Figure 9 This is a cross-sectional view of the circulating desorption device in the fly ash dioxin removal device of Embodiment 1 of this application;

[0038] Figure 10 yes Figure 9 Enlarged view of the structure at point A in the middle;

[0039] Figure 11 This is a longitudinal cross-sectional view of the circulating desorption device in the fly ash dioxin removal device of Embodiment 1 of this application;

[0040] Figure 12 This is a cross-sectional view of the conveying cylinder in the fly ash dioxin removal device of Embodiment 1 of this application;

[0041] Figure 13 This is a schematic diagram of the structure of the drum in the fly ash dioxin removal device of Embodiment 1 of this application;

[0042] Figure 14 This is a cross-sectional view of the drum in the fly ash dioxin removal device of Embodiment 1 of this application;

[0043] Figure 15 This is a longitudinal cross-sectional view of the drum in the fly ash dioxin removal device of Embodiment 1 of this application;

[0044] Figure 16 This is a flowchart of the fly ash dioxin removal method of Embodiment 2 of this application.

[0045] Figure label:

[0046] 1. Temperature control assembly; 101. First air valve; 102. Second air valve; 2. Exhaust duct; 201. First branch air duct; 202. Second branch air duct; 203. First air duct; 3. Incineration system; 301. Incinerator; 302. Secondary air duct; 303. Primary waste heat recovery equipment; 304. Secondary waste heat recovery equipment; 305. Slag silo; 306. Waste pit; 307. Primary air duct; 30 8. Exhaust gas pretreatment equipment; 309. Baghouse dust collector; 310. Transfer ash silo; 311. Exhaust gas post-treatment equipment; 312. Exhaust stack; 313. Ash silo; 4. Circulating desorption device; 401. Shell; 4011. Inner shell; 4012. Outer shell; 402. Base; 403. Hydraulic cylinder; 404. Fly ash inlet; 405. Flue gas outlet; 406. Fly ash outlet; 407. 408. Drum; 409. Accumulation plate; 410. First connecting rod; 411. Mesh cylinder; 412. Second connecting rod; 413. Drone blade; 414. Conveying cylinder; 415. Feed port; 416. Discharge port; 417. Annular exhaust duct; 418. Flue gas inlet; 419. First baffle; 420. Second baffle; 421. Power source; 422. Gear ring; 423. Motor; 424. Gear; 425. Auxiliary heating space; 426. Auxiliary heating air inlet; 427. Auxiliary heating air outlet; 428. First limit ring; 409. Second limit ring; 400. Hydraulic controller; 5. Dust baffle; 6. Material level sensor; 7. Second air duct; 8. First temperature sensor; 9. Fan; 10. Second temperature sensor; 11. Particulate matter detector; 12. Rotary feeder; 13. Mixing chamber; 14. Controller. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0048] Example 1

[0049] like Figure 2As shown, the incineration system includes an incinerator 301, a secondary air duct 302, a primary waste heat recovery device 303, a secondary waste heat recovery device 304, a slag silo 305, a waste pit 306, a primary air duct 307, a flue gas pretreatment device 308, a bag filter 309, a flue gas post-treatment device 311, and an exhaust stack 312. Existing waste incineration processes generally involve storing the waste to be incinerated in the waste pit 306, transporting the waste to the incinerator 301 for incineration, utilizing the primary waste heat recovery device 303 to recover heat from the flue gas, and then utilizing the secondary waste heat recovery device 304 to further recover heat from the flue gas. Secondary recycling is carried out. The slag is transported to the slag silo 305 for storage. The flue gas is treated by the tail gas pretreatment equipment 308 and then enters the bag filter 309 to filter out the solid particles in the flue gas. These solid particles are called fly ash. The gas is discharged into the atmosphere through the exhaust stack 312 after passing through the tail gas posttreatment equipment 311. In order to avoid the waste gas in the waste pit 306 and the slag silo 305 from polluting the environment, the waste needs to be introduced into the incinerator 301 through the primary air duct 307 and the secondary air duct 302, respectively. On the one hand, it provides the oxygen required for combustion in the incinerator 301, and on the other hand, it avoids the waste from polluting the surrounding environment.

[0050] It should be noted that the oxygen content of the flue gas after incinerator 301 is low, approximately 6%, creating a relatively inert environment that is conducive to the desorption of dioxins from fly ash. The adsorption of dioxins in fly ash meets the requirements as follows: Figure 4 The type I adsorption isotherm model shown, converted to an adsorption isobaric line as follows: Figure 5 As shown, the higher the temperature, the lower the adsorption capacity of dioxins in fly ash. Therefore, the desorption of dioxins from fly ash can be achieved by increasing the ambient temperature of fly ash and reducing the oxygen content in the environment to decrease the adsorption capacity of dioxins in fly ash.

[0051] Furthermore, the results show that the concentration of dioxins in fly ash increases with decreasing particle size. Therefore, dioxins tend to accumulate in fly ash with smaller particle sizes. As the component density increases, the carbon content gradually decreases, indicating that the carbon component in fly ash is mainly distributed in the low-density fraction.

[0052] The boiling point temperature range of dioxins is 315℃-537℃. Research results show that when heated to 400℃, 98% of dioxins volatilize from fly ash into the gas phase. The volatilization process during the heating process between 300℃ and 800℃ is the main mechanism for the removal of dioxins from the solid phase. Further treatment of the volatile phase is required at a heat treatment temperature above 800℃ to decompose and destroy the dioxin macromolecules.

[0053] like Figure 1As shown in the embodiment of this application, a fly ash dioxin removal device includes an exhaust duct 2 with a temperature control component 1. The exhaust duct 2 includes a first duct 203, one end of which is connected to a circulating desorption device 4. The other end of the first duct 203 is connected to a first branch duct 201 and a second branch duct 202. The first branch duct 201 is used to connect the incinerator 301 and the primary waste heat recovery device 303. The second branch duct 202 is used to connect the primary waste heat recovery device 303 and the secondary waste heat recovery device 304. The temperature control component 1 includes a first air valve 101 and a second air valve 102. The first air valve 101 is installed on the first branch duct 201, and the second air valve 102 is installed on the second branch duct 202. The air flows from the incinerator through the first branch duct 201. High-temperature flue gas is drawn out from 301. Under normal circumstances, the temperature inside the incinerator 301 is about 900℃-1050℃. Medium-temperature flue gas is drawn out from the primary waste heat recovery equipment 303 through the second branch duct 202. Under normal circumstances, the temperature of the flue gas after treatment by the primary waste heat recovery equipment 303 is about 200℃-700℃. The temperature of the introduced flue gas can be adjusted by regulating the ratio of high-temperature flue gas to medium-temperature flue gas by adjusting the opening of the first valve and the second valve. The other end of the duct 2 is connected to a circulating desorption device 4. The flue gas outlet 405 of the circulating desorption device 4 is connected to the secondary air duct 302 of the incinerator 301 through the second duct 7. The circulating desorption device 4 is equipped with a first temperature sensor 8. The duct 2 is equipped with a fan 9. The second duct 7 is equipped with a second temperature sensor 10 and a particulate matter detector 11. Figure 3 As shown, the first temperature sensor 8, the fan 9, the second temperature sensor 10, and the particulate matter detector 11 are all electrically connected to the controller 14. The first temperature sensor 8 is installed in the circulating desorption device 4 to detect the temperature of the desorption environment in the circulating desorption device 4, so as to control the temperature during the desorption of dioxins from fly ash. The second temperature sensor 10 is installed in the second gas pipe to detect the temperature of the mixture of gas, dioxins, and a small amount of fly ash that flows back to the incinerator 301, so as to control the temperature of the mixture and prevent the regeneration of dioxins during the recirculation process due to excessively low temperature. The controller 14 can control the operation and output power of the fan 9.

[0054] like Figures 6-15As shown, the circulating desorption device 4 includes a housing 401, with a base 402 hinged to the lower end of the housing 401. A hydraulic cylinder 403 is hinged to the base 402, and the piston rod of the hydraulic cylinder 403 is hinged to the housing 401. One end of the housing 401 is provided with a fly ash inlet 404 and a flue gas outlet 405. The flue gas outlet 405 is connected to the secondary air duct 302 of the incinerator 301 through a second air duct 7. The bottom of the other end of the housing 401 is provided with a fly ash outlet 406. A rotatable drum 407 is installed inside the housing 401. The two ends of the drum 407 are dynamically sealed to the housing 401, meaning that the drum 407 can rotate freely relative to the housing 401, and the fly ash and flue gas inside the housing 401 will not escape from the drum. The connection between the roller 407 and the housing 401 escapes. For example, a dynamic seal between the roller 407 and the housing 401 can be achieved through a structure such as a sealed bearing or a limiting ring. The inner wall of the roller 407 is densely covered with material accumulation plates 408. The function of the material accumulation plates 408 is to push the fly ash at the bottom of the roller 407 to the top of the roller 407 as the roller 407 rotates and then scatter it down. On the one hand, this allows the fly ash to fully contact and react with the high-temperature flue gas blown out of the annular exhaust duct 416, using the high-temperature flue gas to achieve the desorption of dioxins in the fly ash. On the other hand, the fly ash is broken up by impact with the mesh cylinder 410 to improve the desorption effect of dioxins in the fly ash. The mesh cylinder 410 is fixed inside the roller 407 by several first connecting rods 409. A auger blade 412 is fixed inside the casing 410 via a second connecting rod 411. The end of the auger blade 412 near the fly ash outlet 406 is rotatably connected to the casing 401. This rotatable connection means the auger blade 412 can rotate freely relative to the casing 401 along its axis. A conveying cylinder 413 is sleeved around the auger blade 412. The conveying cylinder 413 is fixedly connected to the casing 401; for example, one end of the conveying cylinder 413 is fixed to the inner wall of the casing 401, and the middle is fixed by a support frame to increase the stability of the conveying cylinder 413. A feed port 414 is reserved at the end of the conveying cylinder 413 near the fly ash outlet 406, and a discharge port 415 is reserved at the end of the conveying cylinder 413 away from the feed port 414. An annular air outlet duct 416 is fixedly fitted onto the outside of one end of the feed inlet 414. The annular air outlet duct 416 is connected to a flue gas inlet 417, which is connected to an exhaust pipe 2. A first baffle 418 is hinged to the inside of the end of the housing 401 near the fly ash discharge port 406, and a second baffle 419 is hinged to the inner wall of the end of the housing 401 near the fly ash feed inlet 404. Both the first baffle 418 and the second baffle 419 are connected to a power source 420. The power source 420 can be an electric motor, an electric push rod, a pneumatic rod, or a hydraulic rod, etc. For example, the electric motor drives the first baffle 418 and the second baffle 419 to rotate along the hinge, thereby blocking the fly ash discharge port 406 and the fly ash feed inlet 404.Alternatively, the first baffle 418 and the second baffle 419 can be flipped using an electric push rod. A gear ring 421 is fixedly sleeved on the outer wall of the roller 407, and a motor 422 is fixedly mounted on the outer wall of the housing 401. The shaft of the motor 422 is fitted with a gear 423 that meshes with the gear ring 421. The hydraulic controller 409 of the hydraulic cylinder 403, the motor 422, and the power source 420 are all electrically connected to the controller 14.

[0055] In order to enable the controller 14 to control the first air valve 101 and the second air valve 102, both the first air valve 101 and the second air valve 102 are electrically controlled valves. Both the first air valve 101 and the second air valve 102 are electrically connected to the controller 14. The controller 14 can control the opening and closing of the first air valve 101 and the second air valve 102 and the opening degree, thereby facilitating the automatic adjustment of the temperature of the flue gas introduced from the incineration system 3.

[0056] In the incineration system 3, a bag filter 309 is used to collect fly ash from the flue gas. The collected fly ash is sent to a transfer ash silo 310 for storage via a hopper and fly ash conveyor belt. The transfer ash silo 310 serves as the ash source for the star feeder 12, providing fly ash to the star feeder 12. The fly ash inlet 404 of the circulating desorption device 4 is connected to the output end of the star feeder 12. The input end of the star feeder 12 is used to connect to the transfer ash silo 310. The rotary feeder 12 is electrically connected to the controller 14, thereby using the rotary feeder 12 to transport fly ash from the transfer ash silo 310 through the fly ash inlet 404 to the circulating desorption device 4. The rotary feeder 12 is characterized by its ability to uniformly and continuously supply fly ash to the second air duct 7, ensuring a stable gas-to-solid ratio and enabling normal operation of the pneumatic conveying system. Simultaneously, it isolates the upper and lower air pressures of the rotary feeder 12, thus acting as an airlock. The rotary feeder 12 operates continuously, processing 1.2t-1.6t of fly ash per hour. The output of the rotary feeder 12 can be adjusted in conjunction with the detection data from the downstream particulate matter detector 11.

[0057] To achieve dioxin desorption, both flue gas and fly ash in the first gas tube are sent into the circulating desorption device 4. The flue gas and fly ash are circulated and dynamically mixed in the circulating desorption device 4. The residence time of the flue gas and fly ash mixture in the circulating desorption device 4 is approximately 15-90 minutes. This utilizes the flue gas to provide a high-temperature and low-oxygen environment for the fly ash in the circulating desorption device 4, thereby achieving the desorption of dioxins from the fly ash.

[0058] Because the circulating desorption device 4 of this application requires stopping the feeding of fly ash after a certain amount of fly ash is fed into it, and only after the desorbed fly ash is discharged after a certain amount of fly ash has been circulated and desorbed can the feeding of fly ash continue, the fly ash processing is intermittent. In order to achieve continuous fly ash processing, such as... Figure 1 As shown, the number of circulating desorption devices 4 is set to at least two and the circulating desorption devices 4 are arranged in parallel. By setting at least two circulating desorption devices 4 in parallel, when one of them is in the circulating desorption state and cannot feed fly ash, the other pair of circulating desorption devices 4 is used to feed fly ash and perform circulating desorption of fly ash. When the other circulating desorption device 4 cannot feed, the process is switched to the next circulating desorption device 4 that can add fly ash for fly ash processing. This cycle is repeated to ensure the continuous operation of fly ash processing.

[0059] In a further embodiment, in order to maintain the temperature in the circulating desorption device 4, the housing 401 includes an inner housing 4011 and an outer housing 4012. An auxiliary heating space 424 is reserved between the inner housing 4011 and the outer housing 4012. The auxiliary heating space 424 is provided with an auxiliary heating air inlet 425 and an auxiliary heating air outlet 426. The first temperature sensor 8 is installed on the inner wall of the inner housing 4011. By introducing high-temperature flue gas into the auxiliary heating space 424 between the inner housing 4011 and the outer housing 4012 (wherein, in order to further save energy, the high-temperature flue gas can be high-temperature flue gas introduced from the incinerator 301 using the fan 9 as a power source 420, or it can be high-temperature flue gas introduced from the pipe between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304), the circulating desorption device 4 can be kept warm, which is conducive to maintaining the desorption environment in the circulating desorption device 4 within the temperature range of 650℃-750℃, thereby further improving the desorption effect.

[0060] In a further embodiment, in order to monitor the amount of fly ash inside the circulating desorption device 4, a material level sensor 6 is installed inside the inner shell 4011. The material level sensor 6 is electrically connected to the controller 14. The material level sensor 6 can detect the amount of fly ash inside the circulating desorption device 4 in real time. Based on the amount of fly ash, the feeding of fly ash can be automatically controlled. When the amount of fly ash in the circulating desorption device 4 reaches a preset value, the feeding of fly ash will be automatically stopped.

[0061] To facilitate the installation of the drum 407 and prevent the escape of flue gas from the circulating desorption device 4, a space for installing the drum 407 is reserved in the middle of the inner shell 4011. A first limiting ring 427 is fixedly fitted onto the outer walls of both ends of the drum 407. A second limiting ring 428, which cooperates with the first limiting ring 427, is fixed inside both ends of the inner shell 4011. The mutual limiting effect of the first limiting ring 427 and the second limiting ring 428 allows the drum 407 to rotate freely without deviation. Simultaneously, the first limiting ring 427 and the second limiting ring 428 also serve a sealing function to minimize the leakage of flue gas from the circulating desorption device 4. Furthermore, the auxiliary heating space 424 between the inner shell 4011 and the outer shell 4012 has only two external openings: an auxiliary heating inlet 425 and an auxiliary heating outlet 426, to prevent the escape of auxiliary heating gas from the auxiliary heating space 424.

[0062] like Figure 8As shown, the interior of the circulating desorption device 4 is divided from left to right into an air inlet / discharge zone (i.e., the leftmost area of ​​the housing 401), a circulating rotary high-efficiency desorption zone (i.e., the middle area of ​​the housing 401, which is the area where the drum 407 is located), and an air outlet / inlet zone (i.e., the rightmost area of ​​the housing 401). The circulating rotary high-efficiency desorption zone is divided from top to bottom into a tumbling layer (located in the circulating rotary high-efficiency desorption zone, i.e., the inner wall surface of the drum 407), a dispersion backflushing layer (i.e., the annular area near the screen cylinder 410), and a conveying layer (i.e., the area inside the conveying cylinder 413). The housing 401 is divided into an inner housing 4011 and an outer housing 4012. An auxiliary heating space 424 is provided between the inner housing 4011 and the outer housing 4012. Both ends of the auxiliary heating space 424 are gas inlet and outlet channels, which can be connected to the incinerator 301. The temperature inside the incinerator 301 is approximately 900℃-1050℃. This heat is used for auxiliary heating of the circulating desorption device 4 to ensure that the temperature of the flue gas output from the flue gas outlet 405 of the circulating desorption device 4 is higher than 550℃. To ensure continuous feeding and discharging, the two ends of the circulating desorption device 4 (inlet / outlet zone, outlet / inlet zone) remain stationary, while the middle roller 407 (circulating high-efficiency desorption zone) rotates (driven by a motor 422). A first limiting ring 427 and a second limiting ring 428 are provided at the connection points of the two ends of the roller 407 to ensure a double-layer seal. The screen cylinder 410, auger blades 412, and drum 407 are designed as an integrated structure. A motor 422 drives a gear 423 to rotate, which in turn drives a gear ring 421 and drum 407. During fly ash circulation and desorption, the drum 407, screen cylinder 410, and auger blades 412 rotate synchronously under the drive of the motor 422. Fly ash entering through the fly ash inlet 404 is guided by the second baffle 419 into the drum 407. As the drum 407 rotates, the fly ash at the bottom is pushed to the top of the drum 407 by the ash accumulation plate and then thrown down. Under the action of gravity, the fly ash collides with the rotating screen cylinder 410 and breaks up. The fly ash in the drum 407 is also dispersed by the rotation of the drum 407. As the rotation continues, the fly ash accumulates on the left side of the drum 407. At the same time, the fly ash that is thrown down comes into full contact with the high-temperature flue gas blown out from the annular exhaust duct 416. In the high-temperature (i.e., 650℃-750℃) and low-oxygen environment of the circulating desorption device 4, the dioxins in the fly ash can be desorbed. The fly ash on the left side of the drum 407 can enter the conveying cylinder 413 from the feed port 414. The rotation of the auger blades 412 in the conveying cylinder 413 can transport this part of the fly ash to the right side of the drum 407 and fall into the drum 407 from the discharge port 415. The conveying direction of the fly ash in the conveying cylinder 413 is opposite to the movement direction of the fly ash in the drum 407, thereby realizing the circulation and desorption of fly ash inside the circulating desorption device 4.To ensure uniform mixing of fly ash and high-temperature flue gas, the rotation speed is designed to take into account the different properties of fly ash particles. The rotation speed is controlled so that the fly ash falls under gravity when it reaches the top of the drum 407, allowing for a collision reaction between the fly ash and the high-temperature flue gas. In this embodiment, the housing 401 is configured with an inclined structure, which is automatically adjusted via hydraulic control (the tilt angle of the housing 401 can also be controlled by pneumatic pressure or an electric motor, etc.). The tilt angle is between 5° and 87°.

[0063] It should be noted that, as Figure 8 As shown, fly ash enters from the fly ash inlet 404 on the right side of the circulating desorption device 4, passes through the second baffle 419 and enters the drum 407. A fly ash accumulation zone appears at the second baffle 419. Through the integrated structure, under the rotation of the drum 407, the fly ash enters the dispersion and backflushing layer (i.e., the area near the screen cylinder 410) from the fly ash conveying layer through centrifugal force and the pushing action of the accumulation plate 408. The rotation speed is designed to be 10 r / min-100 r / min, which meets the centrifugal force requirements of fly ash. The screen cylinder 410 is equipped with impact dispersion mesh with uniform aperture size of 1-10 cm. In the dispersion and backflushing layer, high-temperature flue gas is evenly distributed and fly ash is evenly dispersed, and high-temperature flue gas and fly ash are in full contact, thereby achieving the purpose of efficient desorption of dioxins. The fly ash then falls onto the tumbling layer on the wall of the drum 407. This tumbling layer is equipped with multiple accumulation plates 408. The accumulation plates 408 can be configured as obtuse-angled staggered bent plates or staggered arc-shaped plates. During rotation, the fly ash accumulates at the accumulation plates 408 and is then detached after being rotated to a higher position. This process is repeated. The reacted fly ash flows out from the fly ash outlet 406 at the bottom left side of the circulating desorption device 4. Before flowing out, the right end of the first baffle 418 is controlled to flip upward.

[0064] High-temperature flue gas enters through the flue gas inlet 417 on the left side of the circulating desorption device 4 and is ejected through the annular outlet cylinder. This annular outlet cylinder is equipped with annular nozzles, allowing the gas to evenly fill the entire dispersion backflushing layer (i.e., the annular area near the screen cylinder 410). In this dispersion backflushing layer, fly ash and high-temperature flue gas undergo sufficient contact and reaction, while simultaneously performing a backflushing function to prevent fly ash from accumulating and clogging at the screen cylinder 410. The fully reacted air-dust mixture, carrying a small amount of fly ash, flows out through the flue gas outlet 405 at the top right side of the circulating desorption device 4. The flue gas outlet 405 is equipped with a tiltable dust baffle 5. The tilting of the dust baffle 5 can be driven by a motor, electric push rod, or hydraulic rod, etc. The angle of the dust baffle 5 can be adjusted to control the distance between the dust baffle 5 and the flue gas outlet 405, thereby controlling the ash content of the output flue gas and reducing fly ash overflow. To ensure the normal operation of the fly ash inlet 404 and the flue gas outlet 405, check valves are installed at the fly ash inlet 404, fly ash outlet 406, flue gas inlet 417, and flue gas outlet 405.

[0065] To ensure continuous fly ash treatment, at least two rotary feeders 12 and at least two circulating desorption units 4 are installed, operating in a cyclical manner. The fly ash processing capacity of the unit is 1.2t / h-1.6t / h. The diameter-to-length ratio of the circulating desorption unit 4 is 1:1-1:4, the reaction time is 15min-90min, and the inclination is 45°-55°.

[0066] It should be noted that a reversible dust baffle 5 is installed on the inner wall of the housing 401 near the flue gas outlet 405. The dust baffle 5 is installed directly below the flue gas outlet 405 and a certain distance is reserved between it and the flue gas outlet 405. This is to prevent the flue gas in the circulating desorption device 4 from entering the flue gas outlet 405 in a straight line. Instead, it detours around the sides or ends of the dust baffle 5 to the flue gas outlet 405 and is discharged. This reduces the fly ash content in the flue gas output from the flue gas outlet 405 as much as possible. By controlling the rotation speed of the drum 407 and the flipping angle of the dust baffle 5, the fly ash content in the flue gas output from the flue gas outlet 405 can be controlled, thereby achieving the goal of sending 5%-10% of the fly ash back to the incinerator 301 in one operation. Because the activated carbon and other materials added before the bag filter 309 in the incineration system 3 adsorb a large amount of Cl-containing components and metal oxides containing Fe, Cu, etc., these metal oxides on the surface of the activated carbon catalyze the regeneration of dioxins, promoting the secondary generation of dioxins and adsorbing them on these adsorbents. Therefore, fly ash with small particle size contains more dioxins.

[0067] Therefore, to avoid incomplete desorption of dioxins in small-particle fly ash and to prevent the regeneration of dioxins from the separated secondary fly ash, in this embodiment, 5%-10% of the primary fly ash and dioxin mixture are recycled back to the incinerator 301 through the second duct 7 for dioxin decomposition. To prevent the regeneration and re-adsorption of dioxins into the fly ash, the temperature in the second duct 7 should not be lower than 550°C. Furthermore, most of the recycled fly ash consists of activated carbon and other substances, which can be oxidized to carbon dioxide in the incinerator 301 and will not be collected as fly ash again. Therefore, this embodiment also achieves the effect of reducing the amount of primary fly ash.

[0068] It should be noted that dioxins have a boiling point of 421.2℃~446.5℃ and a thermal decomposition temperature above 700℃. Experiments have shown that under a nitrogen atmosphere at 800℃, after pyrolyzing dioxin-containing riverbed sediment for 30 minutes, the concentration of PCDFs in the solid phase product decreased from 0.63 ng-TEQ / g to 0.001 ng-TEQ / g, and after 60 minutes or more, the concentration in the solid phase was 0. This demonstrates that thermal desorption requires a relatively long time and high temperature. Therefore, dioxins cannot be completely desorbed into a gaseous state within a short period of time, and some dioxins remain in the fly ash.

[0069] The synthesis of dioxins requires both carbon and chlorine sources. The primary carbon source often originates from unburned residual carbon in fly ash and activated carbon injected during flue gas treatment. The primary chlorine source tends to deposit on the surface of fly ash particles with a diameter of 10 μm or less. Furthermore, studies using flotation have found that fine particles smaller than 2.0 μm in fly ash contribute 80% of the toxicity equivalent, similar to previous findings that smaller particles contain higher dioxin content. Analysis showed that particles smaller than 2.5 μm account for approximately 11% of the total fly ash volume. Therefore, this system is designed to recycle 5%-10% of the fly ash to reduce the impact of undesorbed dioxins.

[0070] In addition, the temperature of the fly ash after being processed by this system is maintained at no less than 550℃. There is a cooling process during the process of entering the ash silo 313. In order to avoid the regeneration of dioxins in the fly ash during this cooling range, 5%-10% of small particulate fly ash is designed to be recycled back into the furnace, which takes away the carbon source for dioxin generation, cuts off the main conditions for dioxin regeneration, and avoids the regeneration of dioxins during the process of fly ash entering the ash silo 313.

[0071] To avoid direct collision between the high-temperature gas in the second gas duct and the medium-temperature gas (slag blast temperature approximately 200℃) in the secondary air duct 302, which could affect the secondary air duct 302, a mixing chamber 13 is provided for pre-mixing the two gases. The two input ends of the mixing chamber 13 are connected to the second air duct 7 and the slag storage 305, respectively, and the output end of the mixing chamber 13 is connected to the incinerator 301. This ensures that the high-temperature gas and the medium-temperature gas are evenly mixed in the mixing chamber 13 before entering the incinerator 301 through the secondary air duct 302. This prevents the direct collision between the high-temperature gas and the medium-temperature gas from causing the following adverse effects on the secondary air duct 302: 1. High-temperature air and medium-temperature gas... 1. When exposed to high temperatures, thermal stress can occur in the pipe walls due to temperature differences, potentially leading to plastic deformation or fatigue damage in the pipe materials. 2. High-temperature air can cause localized overheating in the pipes, posing safety hazards, especially when the performance of the pipe materials deteriorates at high temperatures. 3. The encounter between high-temperature air and medium-temperature gas can cause pressure fluctuations within the pipes, potentially leading to explosions or other dangerous situations in extreme cases. 4. Temperature changes can cause pipe deformation or damage, increasing maintenance costs. 5. Long-term temperature variations can accelerate the aging of pipe materials, shortening their service life.

[0072] To prevent the temperature of the high-temperature flue gas from dropping, insulation measures are taken for the first duct 203, the second duct 7, the circulating desorption device 4, and other pipes. For example, lightweight, low-insulation ceramic fiber modules are used for insulation.

[0073] In this embodiment, the fly ash dioxin removal device can be organically integrated with the existing waste incineration system 3. It utilizes the high-temperature flue gas from the incinerator 301 in the existing waste incineration process to desorb dioxins from fly ash. The desorbed dioxins are then mixed with air and returned to the furnace for high-temperature oxidation. This ingeniously utilizes the existing waste incineration process and makes full use of online production conditions to achieve the reuse of flue gas waste heat without the need for a large secondary energy input, thereby effectively reducing costs. In addition, since fly ash contains a large amount of substances such as CaO, returning 0.5% of the fly ash to the furnace can reduce the generation of sulfur oxides and reduce the difficulty of subsequent tail gas treatment.

[0074] Example 2

[0075] like Figure 16 As shown, the fly ash dioxin removal method of Embodiment 2 of this application is applied to the fly ash dioxin removal device as described in Embodiment 1. The fly ash dioxin removal method includes:

[0076] S100. Start the fan and adjust the opening of the first air valve and the second air valve according to the detection data of the first temperature sensor (i.e. the first air temperature) to adjust the temperature in the circulating desorption device to 650℃-750℃.

[0077] Specifically, due to the unstable temperature of the high-temperature flue gas drawn out from the incinerator 301 caused by the original inlet air temperature or operating conditions, an air intake is set up between the incinerator 301 and the primary waste heat recovery device 303, and between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304. These intakes are connected to the first branch duct 201 and the second branch duct 202, respectively. A first air valve 101 and a second air valve 102 are also set up. The opening of the first air valve 101 and the second air valve 102 is adjusted according to the temperature detected by the first temperature sensor 8 to achieve the purpose of temperature regulation. If the measured temperature is lower than the initial set air temperature of 650℃ or the set value, the air intake after the incinerator 301 is increased, i.e., the opening of the first air valve 101 is increased, and the air intake between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304 is reduced, i.e., the opening of the second air valve 102 is reduced. If the measured temperature is higher than the initial set air temperature of 750℃ or the set value, the air intake between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304 is increased, i.e., the opening of the second air valve 102 is increased, and the air intake after the incinerator 301 is reduced, i.e., the opening of the first air valve 101 is reduced. The entire process operates automatically, maintaining a constant total air volume in the first air duct 203.

[0078] S200, Start the star feeder 12 and control the ash feeding rate of the star feeder 12 according to the fly ash feed amount detected by the material level sensor 6.

[0079] Specifically, the star-shaped feeder 12 feeds fly ash from the transfer ash silo into the circulating desorption device 4 at a preset rate. The fly ash and high-temperature flue gas are fully mixed in the circulating desorption device 4. To ensure sufficient mixing and desorption rate, the mixture of hot air and fly ash in the first duct 203 stays in the circulating desorption device 4 for 15-90 minutes. Dioxins in the fly ash are desorbed using a high-temperature, low-oxygen environment of 650℃-750℃. The air volume in the first duct 203 is 1000 m³ / s. 3 / h-5000m 3 The feed rate of the star feeder 12 is 1.2t / h-1.6t / h, which not only ensures the desorption rate of dioxins in fly ash, but also ensures the processing efficiency of fly ash.

[0080] S300. Adjust the speed of motor 422 according to the detection data of particulate matter detector 11 so that the flue gas output from flue gas outlet 405 carries a preset amount of fly ash.

[0081] Specifically, the rotation speed of the drum 407 is adjusted by adjusting the speed of the motor 422, and the flip angle of the dust baffle 5 is adjusted to adjust the ash content of the flue gas output from the flue gas outlet 405, so as to achieve the purpose of recycling 5%-10% of the fly ash (i.e., 5%-10% of the original fly ash) of the fly ash in one pass. The amount of fly ash is measured by the particulate matter detector 11 on the second air duct 7. If the amount of fly ash returned to the furnace is less than 5% of the original amount of fly ash, the speed of the motor 422 is appropriately increased by the controller 14 (increasing the motor speed can increase the speed of the drum, increase the agitation rate of the fly ash, thereby increasing the dust content in the air inside the circulating desorption device) and / or the distance between the dust baffle 5 and the flue gas outlet 405 is increased (the larger the distance between the dust baffle and the flue gas outlet, the easier it is for fly ash to escape from the flue gas outlet with the flue gas), thereby increasing the amount of fly ash returned to the furnace. If the amount of fly ash returned to the furnace is greater than 10% of the original amount of fly ash, the speed of the motor 422 is appropriately decreased by the controller 14 and / or the distance between the dust baffle 5 and the flue gas outlet 405 is decreased, thereby reducing the amount of fly ash returned to the furnace. It should be noted that during the addition of fly ash to the circulating desorption device 4 and during the circulating desorption process, the second baffle 419 is in the open state and the first baffle 418 is in the closed state. That is, the first baffle 418 blocks the fly ash outlet 406, so that the fly ash in the circulating desorption device 4 cannot be discharged from the fly ash outlet 406. Instead, the first baffle 418 guides the fly ash to the feed port 414 of the conveying cylinder 413. The rotation of the auger blades 412 transports the fly ash to the right side of the drum 407 to achieve the circulating desorption reaction of the fly ash. The fly ash entering from the fly ash inlet 404 will also enter the drum 407 under the guidance of the second baffle 419 to achieve the circulating desorption reaction of the fly ash. After the desorption is completed, the first baffle 418 is opened by controlling the power source 420 so that the secondary fly ash generated by the desorption can be output from the fly ash outlet 406 of the circulating desorption device 4 to the ash silo 313.

[0082] S400. Adjust the opening of the first valve and the second valve according to the detection data of the second temperature sensor to adjust the flue gas temperature in the second duct to not less than 550℃. For example, if the temperature detected by the second temperature sensor 10 is 500℃ (lower than 550℃), the proportion of high-temperature flue gas drawn from the incinerator 301 can be increased by increasing the opening of the first valve and decreasing the opening of the second valve, thereby increasing the temperature of the flue gas in the first duct 203. If the temperature of the mixture in the second duct 7 has been adjusted to not less than 550℃, but the temperature detected by the first temperature sensor 8 is lower than 650℃, the opening of the first valve should be increased and the opening of the second valve should be decreased to increase the proportion of high-temperature flue gas drawn from the incinerator 301, thereby increasing the temperature in the first duct 203. If the temperature of the mixture in the second duct 7 has been adjusted to not less than 550℃, but the temperature detected by the first temperature sensor 8 is higher than or equal to 650℃, then there is no need to adjust the opening of the first valve and the second valve.

[0083] To improve the desorption effect of dioxins in fly ash, the drum rotation speed and shell angle are adjusted according to the physical properties of the fly ash so that the material accumulation plate on the inner wall of the drum can feed the fly ash at the bottom of the drum to the top of the drum and then drop it. The drum rotation speed is 10r / min-100r / min, and the shell tilt angle is 5°-87° (the tilt angle of the shell needs to be adjusted to ensure that the fly ash in the drum moves to the left side of the drum as it is turned by the material accumulation plate on the inner wall of the drum. The moving speed should not be too fast or too slow, and it is best to maintain a moderate speed). The mesh diameter is 1cm-10cm so that the fly ash can be thrown down after being lifted to the highest point, thereby making the collision between the fly ash and the mesh more intense, improving the crushing and agitation effect of the fly ash, and thus enabling a more complete reaction between the fly ash and the high-temperature flue gas, thereby improving the desorption effect of dioxins in the fly ash.

[0084] To prevent the regeneration of dioxins, the temperature of the fly ash after passing through the circulating desorption device 4 must remain above 550°C. This temperature is measured by the second temperature sensor 10 on the second duct 7. Control is implemented based on the temperature measured by the second temperature sensor 10. If the temperature measured by the second temperature sensor 10 is <550°C, the controller 14 increases the temperature in the first duct 203, i.e., increases the setpoint of the first temperature sensor 8. Following the control logic in step S100, the opening degrees of the first air valve 101 and the second air valve 102 are controlled to further increase the temperature in the second duct 7. The dioxin-containing mixed air then returns to the incinerator 301 through the second duct 7 for combustion, where the dioxins are removed through secondary oxidation.

[0085] In this embodiment, the valve opening and the ash feeding rate of the star feeder 12 can be automatically controlled based on the detection data of the first temperature sensor 8, the second temperature sensor 10, the material level sensor 6, and the particulate matter detector 11. This achieves automated control of the fly ash dioxin removal device, greatly simplifying the control process. At the same time, controlling the fly ash desorption temperature within the range of 650℃-750℃ effectively ensures the desorption rate of dioxins in the fly ash, thereby improving the dioxin removal efficiency. Furthermore, most of the incompletely desorbed dioxins can be transported back to the incinerator 301 through the second air duct 7, which has an internal temperature of not less than 550℃, effectively avoiding dioxin regeneration and eliminating secondary pollution.

[0086] The above are merely preferred embodiments of this application; however, the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and its improved concept, should be covered within the scope of protection of this application.

Claims

1. A fly ash dioxin removal device characterized by comprising: The application relates to a circulating desorption device and a circulating desorption device and incineration system. The circulating desorption device comprises a shell, a base hinged to the lower end of the shell, a hydraulic cylinder hinged to the base, a piston rod of the hydraulic cylinder hinged to the shell, a fly ash feeding port and a flue gas output port arranged at one end of the shell, the flue gas output port connected with a secondary air pipe of an incinerator through a second air pipe, a fly ash discharging port arranged at the bottom of the other end of the shell, a rotatable roller arranged in the shell, a plurality of material accumulation plates densely arranged on the inner wall of the roller, a net cylinder fixed in the roller through a plurality of first connecting rods, a dragon blade fixed in the net cylinder through a second connecting rod, the dragon blade rotatably connected with the shell at one end close to the fly ash discharging port, a conveying cylinder externally sleeved with the dragon blade, the conveying cylinder fixedly connected with the shell, a feeding port reserved at one end of the conveying cylinder close to the fly ash discharging port, a discharging port reserved at one end of the conveying cylinder away from the feeding port, an annular air outlet cylinder fixedly sleeved with the outer end of the conveying cylinder close to the feeding port, the annular air outlet cylinder connected with a flue gas input port, the flue gas input port connected with an air duct, a first baffle hinged to the inner end of the shell close to the fly ash discharging port, a second baffle hinged to the inner wall of the shell close to the fly ash feeding port, the first baffle and the second baffle connected with a power source, a gear ring fixedly sleeved with the outer wall of the roller, a motor fixed to the outer wall of the shell, a gear engaged with the gear ring arranged on the rotating shaft of the motor, and the hydraulic controller of the hydraulic cylinder, the motor and the power source electrically connected with a controller. The incineration system comprises an incinerator, a primary waste heat recovery device and a secondary waste heat recovery device, the air duct comprises a first air pipe, one end of the first air pipe connected with the flue gas input port of the circulating desorption device, the other end of the first air pipe connected with a first branch air pipe and a second branch air pipe, the first branch air pipe used for connecting a pipeline between the incinerator and the primary waste heat recovery device, the second branch air pipe used for connecting a pipeline between the primary waste heat recovery device and the secondary waste heat recovery device, and the temperature adjusting assembly comprising a first air valve and a second air valve, the first air valve arranged in the first branch air pipe, and the second air valve arranged in the second branch air pipe.

2. The fly ash dioxin removal device according to claim 1, characterized by The number of the circulating desorption devices is at least two, and the circulating desorption devices are connected in parallel, the first air valve and the second air valve are electrically controlled valves, and the first air valve and the second air valve are electrically connected with the controller.

3. The fly ash dioxin removal device according to claim 2, characterized by The fly ash feeding port of the circulating desorption device is connected with an output end of a star feeder, an input end of the star feeder used for connecting a fly ash source, and the star feeder electrically connected with the controller. The fly ash feeding port of the circulating desorption device is connected with an output end of a star feeder, an input end of the star feeder used for connecting a fly ash source, and the star feeder electrically connected with the controller.

4. The fly ash dioxin removal device according to claim 2, characterized by The shell comprises an inner shell and an outer shell, an auxiliary heating space is reserved between the inner shell and the outer shell, the auxiliary heating space is provided with an auxiliary heating air inlet and an auxiliary heating air outlet, and the first temperature sensor is installed on the inner wall of the inner shell.

5. The fly ash dioxin removal device according to claim 4, characterized by The inner shell is internally provided with a material level sensor, a space for installing a roller is reserved in the middle of the inner shell, the outer wall of both ends of the roller is fixedly provided with a first limiting ring, the inner wall of both ends of the inner shell is fixedly provided with a second limiting ring matched with the first limiting ring, and the material level sensor is electrically connected with the controller.

6. The fly ash dioxin removal device according to claim 2, characterized by A dust lifting baffle is installed on the inner wall of the shell close to the flue gas outlet.

7. A method for removing fly ash dioxins, characterized by, The method is applied to the device as claimed in any one of claims 3-5, and the method comprises: The fan is started, the opening degrees of the first air valve and the second air valve are adjusted according to the detection data of the first temperature sensor, the temperature in the circulating desorption device is adjusted to 650-750 DEG C, the star feeder is started, the ash feeding rate of the star feeder is controlled according to the fly ash feeding amount detected by the material level sensor, the rotation speed of the motor is adjusted according to the detection data of the particulate matter detector, so that the flue gas output by the flue gas outlet carries a preset amount of fly ash, the opening degrees of the first valve and the second valve are adjusted according to the detection data of the second temperature sensor, and the flue gas temperature in the second air pipe is adjusted to not less than 550 DEG C. The rotation speed of the roller and the angle of the shell are adjusted according to the physical properties of the fly ash, so that the accumulated material plate on the inner wall of the roller can send the fly ash at the bottom of the roller to the top of the roller and then fall off, the rotation speed of the roller is 10-100 r / min, the inclination angle of the shell is 5-87 DEG, and the pore diameter of the mesh cylinder is 1-10 cm. ​ ​ 8. The fly ash dioxin removal method according to claim 7, characterized by, ​ 9. The fly ash dioxin removal method according to claim 7, characterized by, The air volume in the first air pipe is 1000m 3 / h-5000m 3 The ash feeding rate of the star feeder is 1.2t / h-1.6t / h, the reaction time of the flue gas and the fly ash in the circulating desorption device is 15min-90min, and the amount of fly ash carried by the flue gas output from the flue gas outlet is 5%-10% of the original fly ash amount.

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