Device and method for removing dioxin in fly ash

Abstract

The invention 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, tedious process and high cost in the process of removing dioxin in fly aste.The fly ash dioxin removal system comprises an air inducing pipe used for introducing high-temperature flue gas, a circulating desorption device and a secondary air pipe; the system comprises an air guide pipe, a first temperature sensor installed in the air guide pipe, and a fan, a second temperature sensor and a particulate matter detector which are installed in a second air pipe, and a controller. According to the method, the desorption effect of dioxin in fly ash is greatly improved, dioxin mixed air obtained after desorption is returned to a furnace and subjected to high-temperature oxidation, an existing waste incineration technology is ingeniously applied, online production conditions are fully utilized, secondary large energy input is avoided, and therefore the cost is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of fly ash treatment, and in particular to a device and method for removing dioxins from fly ash. Background Art

[0002] Fly ash is generally a substance with various polluting components collected by bag filters after a high-temperature incineration process and a series of treatments. The source industries include garbage incineration, hazardous waste incineration, etc. For example, the garbage incineration industry: As the incineration and disposal of urban domestic garbage becomes more and more common, the production of fly ash from garbage incineration in my country is also increasing. The composition of fly ash is complex, and it absorbs high concentrations of organic and inorganic pollutants from the flue gas. In particular, fly ash contains strong carcinogenic, teratogenic, and mutagenic dioxins and heavy metals. If they are not properly handled, they will be transmitted from the emission source through the atmosphere, rainwater, etc. to various places, polluting the atmosphere and water sources, entering the food chain, and causing harm to people. Therefore, achieving harmless disposal and resource utilization of fly ash is one of the environmental protection issues that need to be solved urgently.

[0003] At present, the disposal technologies of dioxins in fly ash mainly include solidification landfill, biodegradation, chemical removal, low-temperature pyrolysis and high-temperature disposal. Among them, solidification landfill may become a potential source of dioxin pollution in landfills; biodegradation and low-temperature pyrolysis have the advantages of environmental friendliness and low cost, but the degradation efficiency of dioxins is not high; chemical removal has the advantages of low energy consumption and high efficiency, but there is a problem of secondary pollution. The coordinated disposal of fly ash by cement kilns is the current mainstream technology for high-temperature disposal. In order to strictly control the chlorine content, the doping amount of fly ash is very low, so cement kilns can only achieve resource utilization of limited fly ash.

[0004] In addition, water washing treatment is also common, but the removal of dioxins in this process is relatively low. Studies have found that the toxic equivalent of 2,3,7,8-TCDD in ash washing wastewater is the highest, accounting for 33.93% of the total toxic equivalent of ash washing wastewater. The migration rate from raw ash to ash washing wastewater is only 0.26%, and dioxins cannot be effectively removed by this method.

[0005] Existing dioxin removal processes often require the use of equipment for high-temperature desorption and re-oxidation, or the use of inert gas for high-temperature desorption, both of which require the introduction of third-party equipment and processes. The process is cumbersome and difficult to operate, increasing the cost of dioxin removal and treatment.

[0006] For example, the patent "Medium-temperature desorption combined with high-temperature plasma oxidation to destroy dioxin compounds" with publication number TW200736549A uses a temperature between 450-850℃ for desorption, and then the desorbed gas enters a high-temperature plasma oxidation chamber at least 1200℃ to use a plasma torch to oxidize and destroy dioxin compounds in the gas flow, i.e., a plasma torch process. Then, it is discharged after being connected to a quenching tower, a lime reaction tower, an activated carbon injection device, and a filter bag dust collector. Summary of the invention

[0007] The purpose of the present application is to overcome the problems of low removal efficiency, complicated process and high cost in the process of removing dioxins from fly ash in the prior art, 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 induced draft duct with a temperature regulating component, one end of the induced draft duct is used to connect to an incineration system, the other end of the induced draft duct is connected to a circulating desorption device, the flue gas outlet of the circulating desorption device is connected to a secondary air duct of an incinerator through a second air duct, a first temperature sensor is installed in the circulating desorption device, a fan is installed in the induced draft duct, a second temperature sensor and a particle detector are installed in the second air duct, and the first temperature sensor, the fan, the second temperature sensor and the particle detector are all electrically connected to a controller;

[0009] Wherein, the circulating desorption device comprises a shell, a base is hinged at the lower end of the shell, a hydraulic cylinder is hinged at the base, a piston rod of the hydraulic cylinder is hinged to the shell, a fly ash inlet and a smoke outlet are arranged at one end of the shell, the smoke outlet is connected to the secondary air duct of the incinerator through a second air duct, a fly ash outlet is arranged at the bottom of the other end of the shell, a rotatable drum is installed in the shell, the inner wall of the drum is densely covered with material accumulation plates, a mesh cylinder is fixed in the drum through a plurality of first connecting rods, a Jiaolong blade is fixed in the mesh cylinder through a second connecting rod, one end of the Jiaolong blade close to the fly ash outlet is rotatably connected to the shell, a conveying drum is sleeved on the outside of the Jiaolong blade, and the conveying drum is fixedly connected to the shell A feeding port is reserved at one end of the conveying cylinder near the fly ash discharge port, and a discharge port is reserved at one end of the conveying cylinder away from the feeding port. An annular air outlet is fixedly sleeved on the outside of one end of the conveying cylinder near the feeding port, and the annular air outlet is connected to a smoke inlet, and the smoke inlet is connected to an induced draft duct. A first baffle is hingedly arranged inside one end of the shell near the fly ash discharge port, and a second baffle is hingedly arranged on the inner wall of one end of the shell near the fly ash feed port, and both the first baffle and the second baffle are connected to a power source, a gear ring is fixedly sleeved on the outer wall of the drum, and a motor is fixed on the outer wall of the shell, and a gear meshing with the gear ring is installed on the rotating shaft of the motor, and 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 air duct, one end of the first air duct is connected to the flue gas inlet of the circulating desorption device, the other end of the first air duct is connected to a first branch air duct and a second branch air duct, the first branch air duct is used to connect the pipeline between the incinerator and the primary waste heat recovery device, the second branch air 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 is installed on the first branch air duct, and the second air valve is installed on the second branch air duct.

[0011] In some possible implementations, the number of the 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 the first air valve and the second air valve are both electrically connected to the controller. Due to the circulating desorption device of the present application, the feeding of fly ash needs to be stopped after a certain amount of fly ash is fed into the circulating desorption device. The feeding of fly ash can be continued only after a certain amount of fly ash is cyclically desorbed and the desorbed fly ash is discharged, so that the processing of fly ash is intermittent. By setting at least two parallel circulating desorption devices, when one of them is in a circulating desorption state and cannot feed fly ash, fly ash is fed and circulated and desorbed by other pairs of circulating desorption devices, so as to ensure 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 feed port of the circulating desorption device is connected to the output end of a star feeder, the input end of the star feeder is used to connect to an ash source, the star feeder is electrically connected to a controller, and the star feeder is used to deliver fly ash in the ash source (e.g., a transfer ash bin) into the circulating desorption device.

[0013] In some possible implementations, the shell includes 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. By introducing high-temperature flue gas into the auxiliary heating space between the inner shell and the outer shell, the circulating desorption device can be kept warm, which is beneficial for maintaining the desorption environment in the circulating desorption device within the temperature range of 650°C-750°C, thereby being more conducive to 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 drum is reserved in the middle of the inner shell. The outer walls at both ends of the drum are fixedly sleeved with a first limiting ring, and the inside of both ends of the inner shell are fixed with a second limiting ring that cooperates with the first limiting ring. The material level sensor is electrically connected to the controller, and the material level sensor can be used to detect the amount of fly ash in the circulating desorption device in real time. According to the fly ash amount, automatic control of fly ash feeding can be achieved. When the fly ash amount in the circulating desorption device reaches a preset value, the fly ash feeding is automatically stopped. Secondly, the mutual limiting effect of the first limiting ring and the second limiting ring allows the drum to rotate freely without deviation. At the same time, the first limiting ring and the second limiting ring 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 shell near the smoke outlet, wherein the dust baffle is installed directly below the smoke outlet and a certain distance is reserved between the dust baffle and the smoke outlet, so that the smoke cannot enter the smoke outlet in a straight line, but detours from both sides of the dust baffle to the smoke outlet to be discharged, thereby reducing the fly ash content in the smoke output from the smoke outlet as much as possible.

[0016] In a second aspect, a method for removing dioxins from fly ash is provided, which is applied to the device as described in the first aspect, and the method comprises:

[0017] Start the fan, adjust the opening of the first air valve and the second air valve according to the detection data of the first temperature sensor, and adjust the temperature in the circulating desorption device to 650°C-750°C;

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

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

[0020] The openings of the first valve and the second valve are adjusted according to the detection data of the second temperature sensor, and the smoke temperature in the second air duct is adjusted to not less than 550°C.

[0021] In some possible implementations, the drum rotation speed and the shell angle are adjusted according to the physical properties of the fly ash so that the accumulation plate on the inner wall of the drum can deliver 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, the inclination angle of the shell is 5°-87°, and the aperture of the mesh cylinder is 1cm-10cm.

[0022] In some possible implementations, the air volume in the first air duct is 1000m 3 / h-5000m 3 / h, the ash delivery rate of the star feeder is 1.2t / h-1.6t / h, the reaction time of the 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 output port is 5%-10% of the original fly ash amount.

[0023] This application has the following beneficial effects:

[0024] 1. The system of the present application can be organically combined with the existing waste incineration system, and the high-temperature flue gas of the incinerator in the existing waste incineration process is used to desorb dioxins in the fly ash, and then the desorbed dioxins are mixed with air and returned to the furnace for high-temperature oxidation. The existing waste incineration process is cleverly used, and the online production conditions are fully utilized. There is no secondary large energy input, thereby effectively reducing the cost;

[0025] 2. The present application sets a circulating desorption device, which can use the dragon blades to circulate the fly ash at the bottom to the other end, and use the accumulation plate on the inner wall of the drum to carry the fly ash at the bottom of the drum to a high place as the drum rotates and then sprinkle it down, so that the fly ash collides with the mesh tube to achieve the crushing of large particles of fly ash, and at the same time, the fly ash and the high-temperature flue gas blown out of the annular air outlet are fully contacted and reacted, so as to achieve efficient desorption of dioxins in the fly ash, and the flue gas blown out of the annular air outlet can also play a role of backblowing to prevent the accumulation and blockage of fly ash at the mesh tube;

[0026] 3. The method of the present application can automatically control the corresponding valve opening, the ash delivery rate of the star feeder, the inclination angle of the circulating desorption device, and the rotation speed of the drum and the dragon blade according to the detection data of the first temperature sensor, the second temperature sensor and the particle detector, thereby realizing the automatic control of the fly ash dioxin removal device, greatly simplifying the control process, and at the same time controlling the fly ash desorption temperature within the range of 650°C-750°C to effectively ensure the desorption rate of dioxins in the fly ash, thereby improving the removal efficiency of dioxins in the fly ash, and being able to transport most of the dioxins that are not completely desorbed back to the incinerator through the second air duct with an internal temperature of not less than 550°C, effectively avoiding the regeneration of dioxins and eliminating secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 is a structural block diagram of a fly ash dioxin removal device according to Example 1 of the present application;

[0030] Figure 2 It is the structural diagram of the existing waste incineration system;

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

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

[0033] Figure 5 It is the type I adsorption isobar model diagram of dioxins in fly ash;

[0034] Figure 6 It is a schematic diagram of the structure of the circulating desorption device in the fly ash dioxin removal device of Example 1 of the present application;

[0035] Figure 7 It is a front view of the circulating desorption device in the fly ash dioxin removal device of Example 1 of the present application;

[0036] Figure 8 is a transverse cross-sectional view of a circulating desorption device in a fly ash dioxin removal device according to Example 1 of the present application;

[0037] Fig. 9 is a cross-sectional view of a circulating desorption device in a fly ash dioxin removal device according to Example 1 of the present application;

[0038] Fig.10 yes Fig. 9 A magnified view of the structure at center A;

[0039] Fig.11 is a longitudinal cross-sectional view of a circulating desorption device in a fly ash dioxin removal device according to Example 1 of the present application;

[0040] Fig.12 is a cross-sectional view of a conveying cylinder in a fly ash dioxin removal device according to Example 1 of the present application;

[0041] Fig.13 It is a schematic diagram of the structure of the drum in the fly ash dioxin removal device of Example 1 of the present application;

[0042] Fig.14 is a transverse cross-sectional view of a drum in the fly ash dioxin removal device of Example 1 of the present application;

[0043] Fig.15 is a longitudinal cross-sectional view of a drum in the fly ash dioxin removal device of Example 1 of the present application;

[0044] Fig.16 This is a flow chart of the fly ash dioxin removal method of Example 2 of the present application.

[0045] Reference numerals:

[0046] 1. Temperature control component; 101. First air valve; 102. Second air valve; 2. Air 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 storage; 306. Garbage pit; 307. Primary air duct; 308. 8. Exhaust pre-treatment equipment; 309. Bag filter; 310. Transfer ash silo; 311. Exhaust post-treatment equipment; 312. Exhaust pipe; 313. Ash silo; 4. Circulation desorption device; 401. Shell; 4011. Inner shell; 4012. Outer shell; 402. Base; 403. Hydraulic cylinder; 404. Fly ash inlet; 405. Smoke outlet; 406. Fly ash outlet; 407. Drum; 408, material accumulation plate; 409, first connecting rod; 410, net drum; 411, second connecting rod; 412, dragon blade; 413, conveying drum; 414, feeding port; 415, discharge port; 416, annular air outlet; 417, smoke inlet; 418, first baffle; 419, second baffle; 420, power source; 421, gear ring; 422, motor; 423, gear; 424, auxiliary heating space; 425, auxiliary heating air inlet; 426, auxiliary heating air outlet; 427, first limiting ring; 428, second limiting ring; 409, hydraulic controller; 5, dust baffle; 6, material level sensor; 7, second air duct; 8, first temperature sensor; 9, fan; 10, second temperature sensor; 11, particle detector; 12, star feeder; 13, air mixing chamber; 14, controller. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 storage 305, a garbage pit 306, a primary air duct 307, an exhaust gas pre-treatment device 308, a bag filter 309, an exhaust gas post-treatment device 311 and an exhaust pipe 312. The existing garbage incineration process is generally as follows: the garbage to be incinerated is usually stored in the garbage pit 306, the garbage is transported to the incinerator 301 for incineration, the primary waste heat recovery device 303 is used to recover the heat in the flue gas, and the secondary waste heat recovery device 304 is used to recover the heat in the flue gas. Secondary recovery is carried out, the slag is transported to the slag bin 305 for storage, the flue gas is treated by the exhaust gas pre-treatment 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, and the gas is discharged into the atmosphere through the exhaust pipe 312 after the exhaust gas post-treatment equipment 311. In order to prevent the waste gas in the garbage pit 306 and the slag bin 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 incinerator 301 with the oxygen required for combustion, 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 the incinerator 301 is low, about 6%, creating a relatively inert environment, which is conducive to the desorption of dioxins in fly ash. The adsorption of dioxins in fly ash meets the following conditions: Figure 4 The type I adsorption isotherm model shown in Figure 2 is converted to the adsorption isobaric line as shown in Figure 2 Figure 5 As shown, the higher the temperature, the lower the adsorption amount of dioxins in fly ash. Therefore, the desorption of dioxins in fly ash can be achieved by increasing the ambient temperature of fly ash and reducing the oxygen content in the environment to reduce the adsorption amount of dioxins in fly ash.

[0051] In addition, the research results show that as the particle size gradually decreases, the concentration of dioxins in fly ash increases. Therefore, dioxins are easily enriched in fly ash with small particle size. As the density of the component increases, the carbon content gradually decreases, indicating that the carbon component in fly ash is mainly distributed in the low-density level.

[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 during the heating process between 300℃-800℃ is the main mechanism for removing dioxins from the solid phase. A heat treatment temperature above 800℃ is required to further treat the volatile phase to decompose and destroy dioxin macromolecules.

[0053] like Figure 1As shown, a fly ash dioxin removal device involved in an embodiment of the present application includes an induced draft duct 2 with a temperature regulating component 1, wherein the induced draft duct 2 includes a first wind duct 203, one end of the first wind duct 203 is connected to the circulating desorption device 4, and the other end of the first wind duct 203 is connected to a first branch wind duct 201 and a second branch wind duct 202, the first branch wind duct 201 is used to connect the pipeline between the incinerator 301 and the primary waste heat recovery device 303, and the second branch wind duct 202 is used to connect the pipeline between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304, the temperature regulating component 1 includes a first wind valve 101 and a second wind valve 102, the first wind valve 101 is installed on the first branch wind duct 201, and the second wind valve 102 is installed on the second branch wind duct 202, and the first branch wind duct 201 is used to connect the pipeline between the incinerator 301 and the primary waste heat recovery device 303, and the second branch wind duct 202 is used to connect the pipeline between the primary waste heat recovery device 303 and the secondary waste heat recovery device 304, and the temperature regulating component 1 includes a first wind valve 101 and a second wind valve 102, the first wind valve 101 is installed on the first branch wind duct 201, and the second wind valve 102 is installed on the second branch wind duct 202, High-temperature flue gas is drawn out from 301. Generally, the temperature in the incinerator 301 is about 900℃-1050℃. Medium-temperature flue gas is drawn out from the primary waste heat recovery device 303 through the second branch air duct 202. Generally, the temperature of the flue gas treated by the primary waste heat recovery device 303 is about 200℃-700℃. The opening of the first valve and the second valve can be adjusted to adjust the ratio of high-temperature flue gas to medium-temperature flue gas to achieve the adjustment of the introduced flue gas temperature. The other end of the induced draft 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 air duct 7. A first temperature sensor 8 is installed in the circulating desorption device 4. The induced draft duct 2 is installed with a fan 9. The second air duct 7 is installed with a second temperature sensor 10 and a particle detector 11. Figure 3 As shown, the first temperature sensor 8, the fan 9, the second temperature sensor 10 and the particle detector 11 are all electrically connected to the controller 14, wherein the first temperature sensor 8 is installed in the circulating desorption device 4, and is used to detect the temperature of the desorption environment in the circulating desorption device 4, so as to control the temperature when the fly ash desorbs dioxins; the second temperature sensor 10 is installed in the second air pipe, and is used to detect the temperature of the mixture of gas, dioxins and a small amount of fly ash that flows back into the incinerator 301, so as to control the temperature of the mixture, so as to prevent the regeneration of dioxins in the reflow process caused by too low temperature; and the operation and output power of the fan 9 can be controlled by the controller 14.

[0054] like Figure 6-Figure 15As shown, the circulating desorption device 4 includes a shell 401, a base 402 is hinged at the lower end of the shell 401, a hydraulic cylinder 403 is hinged at the base 402, a piston rod of the hydraulic cylinder 403 is hinged to the shell 401, a fly ash feed port 404 and a smoke outlet 405 are arranged at one end of the shell 401, the smoke outlet 405 is connected to the secondary air duct 302 of the incinerator 301 through the second air duct 7, a fly ash outlet 406 is arranged at the bottom of the other end of the shell 401, and a rotatable drum 407 is installed in the shell 401, wherein dynamic sealing is realized between the two ends of the drum 407 and the shell 401, that is, the drum 407 can rotate freely relative to the shell 401, and the fly ash and smoke in the shell 401 will not be discharged from the drum The fly ash at the bottom of the drum 407 can be pushed to the top of the drum 407 as the drum 407 rotates and then falls down. On the one hand, the fly ash is fully contacted and reacted with the high-temperature flue gas blown out by the annular air outlet 416, and the high-temperature flue gas is used to achieve the desorption of dioxins in the fly ash. On the other hand, the fly ash is crushed by the collision with the mesh cylinder 410 to improve the desorption effect of dioxins in the fly ash. The mesh cylinder 410 is fixed in the drum 407 by a plurality of first connecting rods 409. A dragon blade 412 is fixed in 410 by a second connecting rod 411, and the end of the dragon blade 412 close to the fly ash discharge port 406 is rotatably connected to the shell 401, wherein the rotatable connection means that the dragon blade 412 can rotate freely along the axis relative to the shell 401, and the outer sleeve of the dragon blade 412 is provided with a conveying cylinder 413, and the conveying cylinder 413 is fixedly connected to the shell 401, for example: one end of the conveying cylinder 413 is fixed to the inner wall of the shell 401, and the middle part is fixed by a support frame to increase the stability of the conveying cylinder 413, a feeding port 414 is reserved at one end of the conveying cylinder 413 close to the fly ash discharge port 406, and a discharge port 415 is reserved at one end of the conveying cylinder 413 away from the feeding port 414. An annular air outlet 416 is fixedly sleeved on the outside of one end of the material port 414, and the annular air outlet 416 is connected to a smoke inlet 417, and the smoke inlet 417 is connected to the induced draft pipe 2. A first baffle 418 is hingedly connected to the inside of one end of the shell 401 close to the fly ash material port 406, and a second baffle 419 is hingedly connected to the inner wall of one end of the shell 401 close to the fly ash material port 404, and the first baffle 418 and the second baffle 419 are both connected to a power source 420, wherein the power source 420 can be an electric motor, an electric push rod, a gas rod or a hydraulic rod, etc. For example, the first baffle 418 and the second baffle 419 are driven by an electric motor to flip along the hinge, thereby realizing the blocking of the fly ash material port 406 and the fly ash material port 404.Of course, the first baffle 418 and the second baffle 419 can also be turned over by an electric push rod. The outer wall of the drum 407 is fixed with a gear ring 421, and the outer wall of the housing 401 is fixed with a motor 422. The rotating shaft of the motor 422 is equipped with a gear 423 meshing with the gear ring 421. The hydraulic controller 409, the motor 422 and the power source 420 of the hydraulic cylinder 403 are all electrically connected to the controller 14.

[0055] In order to realize the control of the first air valve 101 and the second air valve 102 by the controller 14, the first air valve 101 and the second air valve 102 are both electrically controlled valves, and the first air valve 101 and the second air valve 102 are both electrically connected to the controller 14. The controller 14 can control the switch and the opening size of the first air valve 101 and the second air valve 102, thereby facilitating the purpose of automatically adjusting 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 in the flue gas. The collected fly ash is sent to the transfer ash bin 310 for storage through a funnel and a fly ash conveyor belt. The transfer ash bin 310 is used as an ash source for the star feeder 12 to provide fly ash for the star feeder 12. The fly ash feed port 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 bin 310. The star feeder 12 is electrically connected to the controller 14, so that the fly ash in the transfer ash bin 310 is transported from the fly ash feed port 404 to the circulating desorption device 4 by the star feeder 12. The star feeder 12 is characterized in that it can evenly and continuously provide fly ash to the second air duct 7, which can ensure that the gas and solid are relatively stable, so that the pneumatic conveying can work normally. At the same time, the upper and lower air pressures of the star feeder 12 can be isolated to play a gas locking role. The star feeder 12 operates continuously, and the fly ash processing volume per hour is 1.2t-1.6t. The output of the star feeder 12 can be adjusted in linkage according to the detection data of the particle detector 11 at the rear.

[0057] In order to achieve the desorption of dioxins, the flue gas and fly ash in the first air pipe are sent to the circulating desorption device 4, and the flue gas and fly ash are circulated and dynamically mixed in the circulating desorption device 4. The residence time of the mixture of flue gas and fly ash in the circulating desorption device 4 is about 15min-90min, so that the flue gas is used to provide a high-temperature and low-oxygen environment for the fly ash in the circulating desorption device 4, so as to achieve the desorption of dioxins in the fly ash.

[0058] Due to the circulating desorption device 4 of the present application, the feed of fly ash needs to be stopped after a certain amount of fly ash is fed into the circulating desorption device 4. The feed of fly ash can only be continued after a certain amount of fly ash is circulated and desorbed and the desorbed fly ash is discharged, so that the treatment of fly ash is intermittent. In order to achieve continuous treatment of fly ash, Figure 1 As shown, the number of the 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 parallel circulating desorption devices 4, when one of them is in a circulating desorption state and cannot feed fly ash, fly ash is fed and circulating desorption of fly ash is performed through other pairs of circulating desorption devices 4. When another circulating desorption device 4 cannot feed, switch to the next circulating desorption device 4 that can add fly ash to process the fly ash, and repeat the cycle, thereby ensuring the continuous operation of fly ash treatment.

[0059] In a further embodiment, in order to maintain the temperature in the circulation desorption device 4, the shell 401 includes an inner shell 4011 and an outer shell 4012, and an auxiliary heating space 424 is reserved between the inner shell 4011 and the outer shell 4012, and 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 shell 4011, and by introducing high-temperature flue gas into the auxiliary heating space 424 between the inner shell 4011 and the outer shell 4012 (wherein, in order to further save energy, the high-temperature flue gas can use the fan 9 as the power source 420 to introduce high-temperature flue gas from the incinerator 301, and of course, it can also be the high-temperature flue gas introduced from the pipeline between the primary waste heat recovery equipment 303 and the secondary waste heat recovery equipment 304) can play a role in heat preservation of the circulation desorption device 4, which is beneficial to keep the desorption environment in the circulation desorption device 4 within the temperature range of 650℃-750℃, thereby being more conducive to 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, and the material level sensor 6 is electrically connected to the controller 14. The material level sensor 6 can be used to detect the amount of fly ash in the circulating desorption device 4 in real time, and automatic control of fly ash feeding can be achieved based on the fly ash amount. When the fly ash amount in the circulating desorption device 4 reaches a preset value, the fly ash feeding is automatically stopped.

[0061] In order to complete the installation of the drum 407 and prevent the escape of the flue gas in the circulating desorption device 4, a space for installing the drum 407 is reserved in the middle of the inner shell 4011, and the outer walls at both ends of the drum 407 are fixedly sleeved with a first limiting ring 427, and the interior of the inner shell 4011 at both ends is fixed with a second limiting ring 428 that cooperates with the first limiting ring 427. The mutual limiting effect of the first limiting ring 427 and the second limiting ring 428 allows the drum 407 to rotate freely without being offset. At the same time, the first limiting ring 427 and the second limiting ring 428 can also play a sealing role to minimize the leakage of flue gas in the circulating desorption device 4. In addition, the auxiliary heating space 424 between the inner shell 4011 and the outer shell 4012 only has two external openings, an auxiliary heating air inlet 425 and an auxiliary heating air outlet 426, to prevent the escape of the auxiliary heating gas in 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 intake zone / discharge zone (i.e. the leftmost area of ​​the shell 401), a circulating rotating high-efficiency desorption zone (i.e. the middle area of ​​the shell 401, that is, the area where the drum 407 is located) and an air outlet zone / feed zone (i.e. the rightmost area of ​​the shell 401), and the circulating rotating high-efficiency desorption zone is divided from top to bottom into a flipping layer (located in the circulating rotating high-efficiency desorption zone, i.e. the inner wall of the drum 407), a dispersed backflush layer (i.e. the annular area near the mesh cylinder 410) and a conveying layer (i.e. the area inside the conveying cylinder 413). The shell 401 is divided into an inner shell 4011 and an outer shell 4012. An auxiliary heating space 424 is provided between the inner shell 4011 and the outer shell 4012. The two ends of the auxiliary heating space 424 are gas inlet and outlet channels, which can be connected to the incinerator 301. The temperature in the incinerator 301 is about 900°C-1050°C. The heat is used for auxiliary heating of the circulating desorption device 4 to ensure that the flue gas temperature output by the flue gas outlet 405 of the circulating desorption device 4 is higher than 550°C. In order to ensure continuous feeding and discharging, the two ends of the circulating desorption device 4 (the air inlet area / discharging area, the air outlet area / feeding area) are stationary, and the middle roller 407 (circulating rotating high-efficiency desorption area) rotates (driven by the motor 422). The first limiting ring 427 and the second limiting ring 428 are provided at the connection between the two ends of the roller 407 to ensure double-layer sealing. The mesh drum 410, the dragon blade 412 and the drum 407 are designed as an integrated structure. The motor 422 drives the gear 423 to rotate, and the gear 423 drives the gear ring 421 and the drum 407 to rotate. When the fly ash is circulated and desorbed, the drum 407, the mesh drum 410 and the dragon blade 412 rotate synchronously under the drive of the motor 422. The fly ash entering from the fly ash feed port 404 enters the drum 407 under the guidance of the second baffle 419. 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. The fly ash collides with the rotating mesh drum 410 under the action of gravity and is broken. The fly ash in the drum 407 will also be moved along by the movement of the drum 407. The fly ash is continuously gathered toward the left side of the drum 407 by rotation. At the same time, the discarded fly ash is fully in contact with the high-temperature flue gas blown out from the annular air outlet 416. The dioxins in the fly ash can be desorbed in the high-temperature (i.e., 650°C-750°C) and low-oxygen environment in the circulating desorption device 4. The fly ash on the left side of the drum 407 can enter the conveying drum 413 from the feeding port 414 of the conveying drum 413. The rotation of the dragon blades 412 in the conveying drum 413 can transport this part of the fly ash to the right side of the drum 407 and drop into the drum 407 from the discharge port 415. The conveying direction of the fly ash in the conveying drum 413 is opposite to the movement direction of the fly ash in the drum 407, thereby realizing the circulation and desorption of the fly ash inside the circulating desorption device 4.In order to ensure that the fly ash and the high-temperature flue gas are mixed evenly, the rotation speed design takes into account the properties of different fly ash particles, and controls the fly ash to fall by gravity when it rotates to the top of the drum 407, so that the high-temperature flue gas and the fly ash collide with each other. In this embodiment, the shell 401 is set as an inclined structure, and the inclined structure is automatically adjusted by hydraulic control (the control method of the inclination angle of the shell 401 can of course also be set to air pressure control or motor control, etc.). The inclination angle is 5°-87°.

[0063] It should be noted that if Figure 8 As shown, fly ash enters from the fly ash feed port 404 on the right side of the circulating desorption device 4, enters the drum 407 through the second baffle 419, and a fly ash accumulation area appears at the second baffle 419. Through the integrated structure, the fly ash enters the dispersed backflush layer (i.e., the area near the net drum 410) from the fly ash conveying layer through the centrifugal force and the pushing action of the accumulation plate 408 under the rotation of the drum 407. The rotation speed is designed to be 10r / min-100r / min, which meets the centrifugal force requirements of fly ash. The net drum 410 is provided with an impact dispersion net with a uniform aperture size, and the aperture is 1-10 cm. In the dispersed backflush layer, the high-temperature flue gas is evenly distributed, the fly ash is evenly dispersed, and the high-temperature flue gas and fly ash are fully in contact, thereby achieving the purpose of efficient desorption of dioxins. After that, it falls into the turning layer of the wall of the drum 407, which is provided with a plurality of material accumulation plates 408, wherein the material accumulation plates 408 can be provided as obtuse angle offset bending plates or offset arc plates. During the rotation process, the fly ash is gathered at the material accumulation plates 408 and then transferred to a high place and then separated, and this process is repeated. The reacted fly ash flows out from the fly ash discharge port 406 at the bottom of the left side of the circulating desorption device 4. Before flowing out, the right end of the first baffle 418 is controlled to flip up.

[0064] The high-temperature flue gas enters from the flue gas input port 417 on the left side of the circulating desorption device 4 and is ejected through the annular air outlet tube, which is provided with an annular nozzle so that the gas can evenly fill the entire dispersed backflush layer (i.e., the annular area near the net tube 410). In the dispersed backflush layer, the fly ash and the high-temperature flue gas are fully contacted and reacted, and at the same time, a backflush effect is played to prevent the fly ash from accumulating and clogging at the net tube 410. After the reaction is fully completed, the wind-powder mixture carries a small amount of fly ash and flows out from the flue gas outlet 405 at the top right side of the circulating desorption device 4. The flue gas outlet 405 is provided with a dust baffle 5 that can be flipped. The flipping of the dust baffle 5 can be driven by a motor, an electric push rod or a hydraulic rod, etc. The ash content of the output flue gas can be controlled by adjusting the angle of the dust baffle 5 to adjust the distance between the dust baffle 5 and the flue gas outlet 405, thereby reducing the overflow of fly ash. In order to ensure the normal operation of the fly ash feed port 404 and the smoke outlet 405 , the fly ash feed port 404 , the fly ash outlet 406 , the smoke input port 417 and the smoke outlet 405 are all equipped with check valves.

[0065] In order to ensure the continuous treatment of fly ash, at least two star feeders 12 and at least two circulating desorption devices 4 are set up for cyclic operation. The fly ash treatment capacity of the device is 1.2t / h-1.6t / h. The diameter-to-length ratio of the circulating desorption device 4 is 1:1-1:4, the reaction time is 15min-90min, and the slope is 45°-55°.

[0066] It should be noted that a reversible dust baffle 5 is installed on the inner wall of the shell 401 near the smoke outlet 405, wherein the dust baffle 5 is installed directly below the smoke outlet 405 and a certain distance is reserved between the dust baffle 5 and the smoke outlet 405, so that the smoke in the circulating desorption device 4 cannot enter the smoke outlet 405 in a straight line as much as possible, but detours from the two sides or ends of the dust baffle 5 to the smoke outlet 405 for discharge, thereby reducing the fly ash content in the smoke output from the smoke outlet 405 as much as possible, so that the fly ash content in the smoke output from the smoke outlet 405 can be controlled by controlling the rotation speed of the drum 407 and the flipping angle of the dust baffle 5, thereby achieving the purpose of returning 5%-10% of the fly ash to the incinerator 301 at a time. Since the activated carbon added before the bag filter 309 in the incineration system 3 adsorbs a large amount of Cl-containing components and metal oxides such as Fe and Cu, these metal oxides on the surface of the activated carbon catalyze the regeneration of dioxins, promote the secondary generation of dioxins and adsorb on such adsorbents, therefore, fly ash with small particle size contains more dioxins.

[0067] Therefore, in order to prevent the dioxins in the small-size fly ash from being not completely desorbed and to prevent the separated secondary fly ash from regenerating dioxins, in this embodiment, the fly ash and dioxin mixed gas of 5%-10% of the primary fly ash is returned to the incinerator 301 through the second air duct 7 for dioxin decomposition. In order to prevent the dioxins from being regenerated and re-adsorbed in the fly ash, the temperature in the second air duct 7 should not be lower than 550° C. In addition, most of the fly ash returned to the furnace is activated carbon and other substances, which can be oxidized to generate carbon dioxide in the incinerator 301 and will no longer be collected in the form of fly ash. Therefore, this embodiment can also achieve the effect of reducing the amount of primary fly ash.

[0068] It should be noted that the boiling point of dioxin is 421.2℃~446.5℃, and the thermal decomposition temperature is above 700℃. Experiments have shown that when the riverbed mud containing dioxin is pyrolyzed for 30 minutes at 800℃ in a nitrogen atmosphere, the concentration of PCDFs in the solid phase product drops from 0.63ng-TEQ / g to 0.001ng-TEQ / g. After 60 minutes or more, the concentration in the solid phase is 0. It can be seen that thermal desorption requires a long time and a high temperature. Therefore, in a short period of time, dioxin cannot be completely desorbed into gaseous state, and some dioxin remains in the fly ash.

[0069] In the reaction of synthesizing dioxins, carbon source and chlorine source are needed. The main carbon source often comes from the unburned carbon residue in the fly ash and the activated carbon sprayed during flue gas treatment. The main chlorine source tends to be deposited on the surface of fly ash particles with a particle size of 10μm or less. In addition, a study found through flotation that fine particles with a particle size of less than 2.0μm in fly ash contribute 80% of the toxic equivalent, which is similar to the results of previous studies, that is, the dioxin content in particles with a small particle size is higher. According to tests, the part with a particle size of less than 2.5μm accounts for about 11% of the total fly ash. Therefore, this system is designed to recycle 5%-10% of the fly ash to reduce the impact caused by the failure of some dioxins to be desorbed.

[0070] In addition, the temperature of the fly ash after treatment by this system is maintained at no less than 550°C, and there is a cooling process when entering the ash bin 313. In order to avoid the regeneration of dioxins in the fly ash within this temperature drop range, 5%-10% of the small particle fly ash is designed to be returned to the furnace, taking away the carbon source for the generation of dioxins, cutting off the main condition for the regeneration of dioxins, and avoiding the regeneration of dioxins when the fly ash enters the ash bin 313.

[0071] In order to avoid the direct collision of the high-temperature gas in the second air pipe and the medium-temperature gas (the slag air temperature is about 200°C) in the secondary air pipe 302 to affect the secondary air pipe 302, a mixing chamber 13 is set up for premixing the two gases. The two input ends of the mixing chamber 13 are respectively connected to the second air pipe 7 and the slag storage 305, and the output end of the mixing chamber 13 is connected to the incinerator 301. In this way, the high-temperature gas and the medium-temperature gas are evenly mixed in the mixing chamber 13 and then enter the incinerator 301 through the secondary air pipe 302, thereby avoiding the following adverse effects on the secondary air pipe 302 caused by the direct collision of the high-temperature gas and the medium-temperature gas: 1. The high-temperature air and the medium-temperature gas are mixed. 1. When encountering 2. high-temperature air, thermal stress will be generated on the pipe wall due to the temperature difference, and this thermal stress may cause plastic deformation or fatigue damage to the pipe material; 2. High-temperature air may cause local overheating of the pipe, thereby causing safety hazards, especially when the performance of the pipe material degrades at high temperatures, safety problems are more likely to occur; 3. The encounter between high-temperature air and medium-temperature gas may cause pressure fluctuations in the pipe, and in extreme cases may cause explosions and other dangerous situations; 4. Since temperature changes may cause pipe deformation or damage, the maintenance cost of the pipe may increase; 5. Long-term temperature changes may accelerate the aging of pipe materials, thereby shortening the service life of the pipe.

[0072] In order to prevent the high-temperature flue gas from decreasing in temperature, the first air duct 203, the second air duct 7, the circulating desorption device 4 and other pipelines are all provided with insulation measures, for example, using lightweight low-insulation ceramic fiber modules and other materials for insulation.

[0073] In this embodiment, the fly ash dioxin removal device can be organically combined with the existing waste incineration system 3, and the high-temperature flue gas of the incinerator 301 in the existing waste incineration process is used to desorb dioxins in the fly ash, and then the desorbed dioxin mixed air is returned to the furnace for high-temperature oxidation. The existing waste incineration process is cleverly used, and the online production conditions are fully utilized to realize the reuse of flue gas waste heat. There is no need for secondary large energy investment, thereby effectively reducing costs. In addition, because the fly ash contains a large amount of CaO and other substances, -% of the fly ash can reduce the generation of sulfur oxides after returning to the furnace, reducing the difficulty of subsequent exhaust gas treatment.

[0074] Example 2

[0075] like Fig.16 As shown, a fly ash dioxin removal method involved in Example 2 of the present application is applied to the fly ash dioxin removal device as described in Example 1, and the fly ash dioxin removal method includes:

[0076] S100, start the fan, 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), and adjust the temperature in the circulating desorption device to 650° C.-750° C.;

[0077] Specifically, due to the original intake air temperature or operating conditions in the incinerator 301, the temperature of the high-temperature flue gas drawn out is unstable, and an air intake is set between the incinerator 301 and the first-level waste heat recovery equipment 303 and between the first-level waste heat recovery equipment 303 and the second-level waste heat recovery equipment 304, respectively connecting the first branch air duct 201 and the second branch air duct 202, and respectively setting the first air valve 101 and the second air valve 102, and adjusting the opening of the first air valve 101 and the second air valve 102 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 wind temperature of 650°C or the set value, the air intake after the incinerator 301 is increased, that is, 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, that is, the opening of the second air valve 102 is reduced; if the detected temperature is higher than the initial set wind temperature of 750°C 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, that is, the opening of the second air valve 102 is increased, and the air intake after the incinerator 301 is reduced, that is, the opening of the first air valve 101 is reduced. The whole process runs automatically, keeping the total air volume in the first air duct 203 unchanged.

[0078] S200, starting the star feeder 12, and controlling the ash delivery rate of the star feeder 12 according to the fly ash feed amount detected by the material level sensor 6;

[0079] Specifically, the star feeder 12 delivers the fly ash in the intermediate ash storage from the fly ash input port to the circulating desorption device at a preset rate. The fly ash and the high-temperature flue gas are fully mixed in the circulating desorption device 4. In order to ensure sufficient mixing and desorption rate, the mixture of hot air and fly ash in the first air duct 203 stays in the circulating desorption device 4 for 15min-90min, and the dioxins in the fly ash are desorbed in a high-temperature low-oxygen environment of 650℃-750℃. The air volume in the first air duct 203 is 1000m 3 / h-5000m 3 / h, the ash delivery rate of the star feeder 12 is 1.2t / h-1.6t / h, which not only ensures the desorption rate of dioxins in the fly ash, but also ensures the treatment efficiency of the fly ash.

[0080] S300, adjusting the rotation speed of the motor 422 according to the detection data of the particle detector 11, so that the flue gas output from the 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 rotation speed of the motor 422, and the ash content of the flue gas output from the flue gas outlet 405 is adjusted by adjusting the flip angle of the dust baffle 5, so as to achieve the purpose of finally returning 5%-10% of the primary fly ash (i.e. 5%-10% of the original fly ash) to the furnace. The amount of fly ash is measured by the particle 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 fly ash amount, the speed of the motor 422 is appropriately increased through the controller 14 (increasing the motor speed can increase the speed of the drum, increase the stirring rate of the fly ash, and thus increase the dust content in the air in the circulating desorption device) and / or increase the distance between the dust baffle 5 and the smoke outlet 405 (the larger the distance between the dust baffle 5 and the smoke outlet, the easier it is for the fly ash to escape from the smoke outlet with the smoke), 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 fly ash amount, the speed of the motor 422 is appropriately reduced through the controller 14 and / or the distance between the dust baffle 5 and the smoke outlet 405 is reduced, thereby reducing the amount of fly ash returned to the furnace. It should be noted that when adding fly ash to the circulating desorption device 4 and during the circulating desorption process, the second baffle 419 is in an open state and the first baffle 418 is in a closed state, that is, the fly ash outlet 406 is blocked by the first baffle 418, so that the fly ash in the circulating desorption device 4 cannot be discharged from the fly ash outlet 406, but the first baffle 418 is used to guide the fly ash to the feed port 414 of the conveying cylinder 413, and the rotation of the dragon blade 412 is used to transport the fly ash to the right side of the drum 407 to realize the circulating desorption reaction of the fly ash, and the fly ash entering from the fly ash feed port 404 will also enter the drum 407 under the guidance of the second baffle 419 to realize 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 desorption can be output from the fly ash outlet 406 of the circulating desorption device 4 to the ash bin 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 air duct to not less than 550°C. For example, if the temperature detected by the second temperature sensor 10 is 500°C (lower than 550°C), the proportion of high-temperature flue gas drawn out from the incinerator 301 can be increased by increasing the opening of the first valve and reducing the opening of the second valve, thereby increasing the temperature of the flue gas in the first air duct 203. If the temperature of the mixture in the second air duct 7 has been adjusted to not less than 550°C, but the temperature detected by the first temperature sensor 8 is lower than 650°C, the opening of the first valve should be increased and the opening of the second valve should be reduced to increase the proportion of high-temperature flue gas drawn out from the incinerator 301, thereby increasing the temperature in the first air duct 203. If the temperature of the mixture in the second air duct 7 has been adjusted to not less than 550°C, but the temperature detected by the first temperature sensor 8 is higher than or equal to 650°C, there is no need to adjust the opening of the first valve and the second valve.

[0083] In order to improve the desorption effect of dioxins in fly ash, the drum speed and the shell angle are adjusted according to the physical properties of the fly ash so that the accumulation plate on the inner wall of the drum can send the fly ash at the bottom of the drum to the top of the drum and then drop it. The drum speed is 10r / min-100r / min, and the inclination angle of the shell is 5°-87° (wherein, the adjustment of the inclination angle of the shell needs to ensure that the fly ash in the drum moves to the left side of the drum during the turning of the accumulation plate on the inner wall of the drum, and the moving speed cannot be too fast or too slow, and it is best to maintain a moderate speed). The aperture of the mesh cylinder is 1cm-10cm, so that the fly ash can be thrown down after being lifted to the highest point, so that the collision between the fly ash and the mesh cylinder is more intense, and the crushing and stirring effects of the fly ash are better, so that the reaction between the fly ash and the high-temperature flue gas can be more sufficient, thereby improving the desorption effect of dioxins in the fly ash.

[0084] In order to avoid the regeneration of dioxins, it is necessary to ensure that the temperature of the fly ash after the circulation desorption device 4 is still higher than 550°C, and the temperature is measured by the second temperature sensor 10 on the second air duct 7. Corresponding control is performed according to the temperature measured by the second temperature sensor 10. If the temperature measured by the second temperature sensor 10 is less than 550°C, the temperature in the first air duct 203 is increased by the controller 14, that is, the setting value of the first temperature sensor 8 is increased, and the opening of the first air valve 101 and the second air valve 102 is controlled according to the control logic in step S100 to increase the temperature in the second air duct 7. After that, the dioxin mixed air returns to the incinerator 301 through the second air duct 7 for combustion, and the dioxins are removed in the incinerator 301 through secondary oxidation.

[0085] In this embodiment, the corresponding valve opening and the ash delivery rate of the star feeder 12 can be automatically controlled according to the detection data of the first temperature sensor 8, the second temperature sensor 10, the level sensor 6 and the particle detector 11, thereby realizing the automatic control of the fly ash dioxin removal device, greatly simplifying the control process, and at the same time controlling the fly ash desorption temperature within the range of 650°C-750°C to effectively ensure the desorption rate of dioxins in the fly ash, thereby improving the removal efficiency of dioxins in the fly ash, and being able to transport most of the dioxins that are not completely desorbed back to the incinerator 301 through the second air duct 7 with an internal temperature of not less than 550°C, effectively avoiding the regeneration of dioxins and eliminating secondary pollution.

[0086] The above are only preferred specific implementations of the present application; however, the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved ideas of the present application within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A fly ash dioxin removal device, characterized in that: It includes an induced draft duct with a temperature adjustment component, one end of the induced draft duct is used to connect to the incineration system, the other end of the induced draft duct is connected to a circulating desorption device, the smoke outlet of the circulating desorption device is connected to the secondary air duct of the incinerator through a second air duct, a first temperature sensor is installed in the circulating desorption device, a fan is installed in the induced draft duct, a second temperature sensor and a particle detector are installed in the second air duct, and the first temperature sensor, the fan, the second temperature sensor and the particle detector are all electrically connected to the controller; Wherein, the circulating desorption device comprises a shell, a base is hinged at the lower end of the shell, a hydraulic cylinder is hinged at the base, a piston rod of the hydraulic cylinder is hinged to the shell, a fly ash inlet and a smoke outlet are arranged at one end of the shell, the smoke outlet is connected to the secondary air duct of the incinerator through a second air duct, a fly ash outlet is arranged at the bottom of the other end of the shell, a rotatable drum is installed in the shell, the inner wall of the drum is densely covered with material accumulation plates, a mesh cylinder is fixed in the drum through a plurality of first connecting rods, a Jiaolong blade is fixed in the mesh cylinder through a second connecting rod, one end of the Jiaolong blade close to the fly ash outlet is rotatably connected to the shell, a conveying drum is sleeved on the outside of the Jiaolong blade, and the conveying drum is fixedly connected to the shell A feeding port is reserved at one end of the conveying cylinder near the fly ash discharge port, and a discharge port is reserved at one end of the conveying cylinder away from the feeding port. An annular air outlet is fixedly sleeved on the outside of one end of the conveying cylinder near the feeding port, and the annular air outlet is connected to a smoke inlet, and the smoke inlet is connected to an induced draft duct. A first baffle is hingedly arranged inside one end of the shell near the fly ash discharge port, and a second baffle is hingedly arranged on the inner wall of one end of the shell near the fly ash feed port, and both the first baffle and the second baffle are connected to a power source, a gear ring is fixedly sleeved on the outer wall of the drum, and a motor is fixed on the outer wall of the shell, and a gear meshing with the gear ring is installed on the rotating shaft of the motor, and the hydraulic controller, motor and power source of the hydraulic cylinder are all electrically connected to the controller.

2. The fly ash dioxin removal device according to claim 1, characterized in that: 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 air duct, one end of which is connected to the flue gas input port of the circulating desorption device, and the other end of the first air duct is connected to a first branch air duct and a second branch air duct. The first branch air duct is used to connect the pipeline between the incinerator and the primary waste heat recovery device, and the second branch air 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 is installed on the first branch air duct, and the second air valve is installed on the second branch air duct.

3. The fly ash dioxin removal device according to claim 2, characterized in that: The number of the 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 the first air valve and the second air valve are both electrically connected to the controller.

4. The fly ash dioxin removal device according to claim 3, characterized in that: The fly ash feed port of the circulating desorption device is connected to the output end of the star-shaped feeder, the input end of the star-shaped feeder is used to connect to the ash source, and the star-shaped feeder is electrically connected to the controller.

5. The fly ash dioxin removal device according to claim 3, characterized in that: 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.

6. The fly ash dioxin removal device according to claim 5, characterized in that: 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. The outer walls at both ends of the roller are fixed with a first limiting ring, and the inside of both ends of the inner shell are fixed with a second limiting ring that matches the first limiting ring. The material level sensor is electrically connected to the controller.

7. The fly ash dioxin removal device according to claim 3, characterized in that: A dust baffle is installed on the inner wall of the shell near the smoke outlet.

8. A method for removing dioxins from fly ash, characterized in that: Applied to the device according to any one of claims 4 to 6, the method comprises: Start the fan, adjust the opening of the first air valve and the second air valve according to the detection data of the first temperature sensor, and adjust the temperature in the circulating desorption device to 650°C-750°C; Start the star feeder and control the ash feeding rate of the star feeder according to the fly ash feed amount detected by the material level sensor; The speed of the motor is adjusted according to the detection data of the particle detector so that the flue gas output from the flue gas outlet carries a preset amount of fly ash; The openings of the first valve and the second valve are adjusted according to the detection data of the second temperature sensor, and the smoke temperature in the second air duct is adjusted to not less than 550°C.

9. The method for removing dioxins from fly ash according to claim 8, characterized in that: The drum speed and the shell angle are adjusted according to the physical properties of the fly ash so that the accumulation plate on the inner wall of the drum can deliver the fly ash at the bottom of the drum to the top of the drum and then drop it. The drum speed is 10r / min-100r / min, the shell inclination angle is 5°-87°, and the aperture of the mesh cylinder is 1cm-10cm.

10. The method for removing dioxins from fly ash according to claim 8, characterized in that: The air volume in the first air duct is 1000m 3 / h-5000m 3 / h, the ash delivery rate of the star feeder is 1.2t / h-1.6t / h, the reaction time of the 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 output port is 5%-10% of the original fly ash amount.

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