In-situ rapid detoxification intelligent integrated disposal system for dioxin in fly ash of waste incineration plant

Abstract

The present application relates to hazardous waste treatment technology, and aims to provide a fly ash dioxin in-situ rapid detoxification intelligent integrated disposal system for a waste incineration plant. The system comprises a plurality of bag dust removal modules arranged in series on a flue, the adjacent modules are connected by pipelines to realize continuous air intake, and low-temperature thermal decomposition modules are arranged at the bottom of each module. A stirring mechanism is arranged in the cavity of the low-temperature thermal decomposition module, the side parts of adjacent modules are each provided with a uniform material port and are connected by a pipeline, and each module is provided with an ash discharge port at the bottom and is connected to a fly ash storage container by a pipeline. The present application can realize in-situ efficient low-temperature thermal decomposition of fly ash dioxin, realize rapid detoxification of fly ash, reduce process energy consumption and environmental risk, realize near-zero emission of waste incineration power plants; can realize gradient disposal of flue gas and fly ash at the same time, improve the fly ash interception and gas passing efficiency as a whole, and realize the coordination and unity of the fly ash decomposition amount in each module and the temperature in the module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pollutant disposal, particularly relates to solid waste incineration tail gas and fly ash pollutant control technology, and specifically relates to a waste incineration plant fly ash dioxin in-situ rapid detoxification intelligent integrated disposal system and method. BACKGROUND

[0002] With the continuous growth of solid waste, especially municipal solid waste, incineration treatment as an effective way to achieve reduction, resource utilization and harmlessness of solid waste is increasingly widely used. However, the incineration process of waste will produce carcinogens such as dioxins, which are usually captured into the solid phase by injecting activated carbon and become part of fly ash. Fly ash falls into the ash bin after being intercepted by the dust collector and is transported to special equipment for detoxification treatment. During the transportation and disposal of fly ash, a large amount of fly ash waste heat is dissipated, and dioxins have the risk of escaping; even if high-temperature treatment is performed, the tail gas may cause secondary pollution. Therefore, rapid reduction of dioxin toxicity is an important step in the resource utilization of fly ash.

[0003] Low-temperature thermal decomposition is a technology for decomposing dioxins in fly ash by low-temperature heating in a non-oxidizing atmosphere. Compared with cement kiln co-processing and fly ash melting, the low-temperature thermal decomposition uses a temperature of 250-500°C, has relatively low energy consumption, and can reduce the dioxin content in fly ash by more than 95%, meeting the requirements of “Technical Specifications for Pollution Control of Municipal Solid Waste Incineration Fly Ash (Trial)” (HJ 1134) and achieving near-zero solid-phase dioxin emissions. However, the low-temperature thermal decomposition tail gas poses an environmental risk and needs to be treated by secondary combustion and adsorption, resulting in huge energy consumption and additional costs. The decomposition temperature and reducing atmosphere are decisive factors for the efficiency of low-temperature thermal decomposition of dioxins. Due to the large temperature difference inside large equipment and the lack of intelligent control systems, it is difficult to ensure efficient dioxin decomposition of fly ash at a stable temperature and atmosphere; moreover, the equipment is prone to serious caking, greatly reducing the efficiency of low-temperature thermal decomposition and possibly causing blockage and even shutdown. In terms of materials, the existing treatment methods involve fly ash storage, transportation and feeding, and a large amount of newly captured fly ash waste heat is wasted, additional consumption is generated in the intermediate process, and there is a risk of dioxin escape, which is not an ideal way for rapid detoxification of fly ash dioxins.

[0004] For example, Chinese Patent Application CN 118341803A discloses a fly ash dioxin low-temperature thermal decomposition system that uses a transportation pipeline to transport fly ash in a temporary storage bin to a pyrolysis system for treatment. A large amount of waste heat is dissipated from the fly ash, increasing energy consumption, and there is a risk of environmental pollution from dioxins during the transportation process. Moreover, the temperature in the pyrolysis section is controlled by the original DSC automatic control system of the power plant, which cannot achieve real-time control of the internal temperature and cannot regulate the uniform heating of fly ash.

[0005] Chinese patent application CN 115488137A discloses a dioxin degradation system and method for fly ash from waste incineration, which transports fly ash into a low-temperature thermal decomposition device through a conveying device, pyrolyzes at 300-450℃ for 1-2h in a nitrogen atmosphere, completes product cooling after passing into a cooling equipment, and treats exhaust gas by passing into a subsequent exhaust gas treatment unit. The system has a complex structure, contains multiple complex units such as conveying equipment, low-temperature thermal decomposition equipment, cooling equipment, and product collection equipment, and the unit connection section is prone to gas leakage, which is difficult to ensure the reducing atmosphere of degradation; at the same time, the equipment continuously and uninterruptedly feeds fly ash into a rotary electric heating low-temperature thermal decomposition device, and only controls the temperature of the heating module by regulating the temperature of fly ash on both sides, which is difficult to ensure uniform heating in the device, and it is difficult to control the center temperature, the dioxin degradation effect is difficult to guarantee, the power consumption is large, the economy is poor, and there is also the risk of environmental pollution of dioxin in the transportation process.

[0006] In summary, the current waste incineration plants generally lack a means to achieve in-situ efficient and rapid integrated removal of fly ash dioxin; a large amount of dioxin leaves the waste incineration plant in the form of fly ash, causing additional disposal costs and huge environmental risks. Therefore, there is an urgent need for an intelligent integrated disposal technology for fly ash dioxin in-situ rapid detoxification of waste incineration plants, which can achieve near-zero solid-phase dioxin emission at low cost and high efficiency, reduce environmental risks, and save energy and reduce carbon. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide an intelligent integrated disposal system and method for fly ash dioxin in-situ rapid detoxification of waste incineration plants.

[0008] To solve the technical problem, the solution of the present application is:

[0009] An intelligent integrated disposal system for fly ash dioxin in-situ rapid detoxification of waste incineration plants, characterized in that it comprises a bag dust removal module arranged on a flue, and a matching low-temperature thermal decomposition module, a fly ash storage container and a wisdom control module; wherein,

[0010] The bag dust removal module has multiple modules and is arranged in series, the furnace is connected to the gas inlet of the first module through the flue, the adjacent modules are connected by pipelines to realize continuous gas inlet, and the gas outlets at the top of each module are connected to an exhaust gas treatment unit; a low-temperature thermal decomposition module is arranged at the bottom of each bag dust removal module, and is connected through the respective ash outlet and ash inlet, and an electric control valve is arranged at the ash outlet;

[0011] The low-temperature thermal decomposition module has a hollow inner cavity, a stirring mechanism is arranged in the cavity, and a heater is arranged outside the cavity; a nitrogen gas inlet is arranged at the lower part of the cavity, and an exhaust gas outlet is arranged at the top of the cavity; the side parts of adjacent low-temperature thermal decomposition modules are each provided with a material equalizing port and are connected through pipelines, and an electric control valve is arranged at the material equalizing port; the bottom of the cavity of each module is provided with an ash discharge port, which is respectively connected to a fly ash collecting container through a pipeline, and an electric control valve is arranged at the ash discharge port;

[0012] The intelligent control module comprises a man-machine dialogue interface and a main control board, and the main control board is connected with the following through cables: a differential pressure sensor and an ash content meter arranged in the bag dust removal module, an ash content meter, a temperature sensor and an oxygen sensor arranged in the low-temperature thermal decomposition module, a temperature control device of the heater, a speed regulator of the stirring mechanism, and the electric control valves arranged at the ash discharge port, the material equalizing port and the ash discharge port.

[0013] As a preferred scheme of the present application, the bag dust removal module has a hollow cavity, which is divided into two parts by a top partition; a plurality of vertical hollow bags are mounted on the partition with their open ends, and differential pressure sensors are arranged on both sides of the partition; a back flushing pipe is arranged in each bag, and the back flushing pipes are connected to an air inlet pipe provided with a pulse valve; the lower part of the cavity is a reverse cone-shaped ash hopper, a spiral ash guide plate is arranged on the inner wall of the ash hopper, and an ash content meter is arranged on the upper edge of the ash hopper, and an ash discharge port is arranged at the bottom of the ash hopper.

[0014] As a preferred scheme of the present application, each bag dust removal module is provided with a parallel pipeline for introducing flue gas, and a matched valve is arranged on the parallel pipeline and the pipeline connecting adjacent modules; by switching the valve, the flue gas can pass through a certain module which is short-circuited, so that the system can continuously operate.

[0015] As a preferred scheme of the present application, the nitrogen gas inlet of the low-temperature thermal decomposition module is connected to a nitrogen source through a pipeline, a flow meter is arranged on the pipeline, and the flow meter is connected to the main control board through a cable; the temperature sensor has a plurality of temperature sensors, which are arranged on the shaft of the stirring mechanism and on the inner wall of the cavity; the heater is an electric heater or a flue gas heat exchanger; the ash content meter is arranged on the inner wall of the cavity below the exhaust gas outlet.

[0016] As a preferred scheme of the present application, the cavity of the low-temperature thermal decomposition module is provided with a conical ash guide plate, or at least two inclined ash guide plates are arranged in the cavity to form an enclosed area with a large upper end and a small lower end, and the stirring mechanism is located in the center of the enclosed area; the stirring mechanism is a double-shaft spiral stirring structure, the cross section of the paddle of the stirring structure gradually increases from bottom to top, and maintains a distance with the ash guide plate; the rotating directions of the blades on the two rotating shafts are opposite, so that the fly ash being stirred can move upward.

[0017] As a preferred scheme of the present application, the exhaust gas outlets at the top of each low-temperature thermal decomposition module are respectively connected to a discharge pipe through pipelines, and the discharge pipe is sequentially connected to a filter, an induced draft fan and a furnace gas inlet.

[0018] As a preferred scheme of the present application, each low-temperature thermal decomposition module is arranged in sequence with the position of the bag-type dust collector module, and arranged in a step-down manner; the uniform material inlet of the module at the rear stage is lower than the uniform material outlet of the module at the front stage, and the connecting pipeline between the two is arranged obliquely, forming an included angle with the horizontal direction.

[0019] The present application also provides an intelligent integrated disposal method for dioxin in-situ rapid detoxification of fly ash in a waste incineration plant by using the aforementioned system, comprising:

[0020] (1) When the bag-type dust collector module is initially put into use, nitrogen is introduced into the low-temperature thermal decomposition module, the heater and the induced draft fan are started when the pressure difference in the bag-type dust collector module reaches the set value; when the pressure difference in the bag-type dust collector module further increases to the preset value, the electric control valve of the ash outlet is opened according to the set time length, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module; after the electric control valve is closed, the stirring structure is started, and the reaction temperature in the low-temperature thermal decomposition process is controlled to be 300-400℃;

[0021] (2) Since the fly ash in the flue gas continuously accumulates in the bag-type dust collector module during production, the electric control valve needs to be opened for fly ash discharge operation according to the detection signal of the ash amount gauge; if the ash amount gauge signal in the low-temperature thermal decomposition module is detected, the electric control valve of the uniform material inlet of the current low-temperature thermal decomposition module and the next stage low-temperature thermal decomposition module is opened, so that the excess fly ash enters the next stage low-temperature thermal decomposition module from the connecting pipeline; the ash amount control and discharge operation of each stage bag-type dust collector module, and the ash amount control and excess material release in the low-temperature thermal decomposition module are all executed in this way;

[0022] (3) Nitrogen is continuously input during the low-temperature thermal decomposition process, the generated tail gas is filtered and sent back to the furnace by the induced draft fan, and the harmful components generated in the thermal decomposition process are eliminated by combustion; after the fly ash stays for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash discharge port is opened, and the disposed fly ash is discharged into the fly ash storage container.

[0023] As a preferred scheme of the present application, the amount of fly ash in each stage low-temperature thermal decomposition module is controlled to have a gradient decreasing trend, and the amount of fly ash in the module at the rear stage is less than that in the module at the front stage.

[0024] As a preferred scheme of the present application, the nitrogen gas inlet flow rate in each stage low-temperature thermal decomposition module is controlled to be 1-5L / min, the oxygen concentration is controlled to be <0.5%, the stirring speed is controlled to be 3-20r / min, and the reaction time is controlled to be 0.5-1h.

[0025] Invention principle description:

[0026] The inventors noticed in the research that the existing pollutant control technology of waste incineration power plants can only transfer gas-phase dioxins to the solid phase, and cannot achieve near-zero emission of dioxins. The subsequent disposal of solid-phase dioxins is done by downstream enterprises each doing its own thing, and there is a serious environmental risk. Although low-temperature thermal decomposition technology can be applied to fly ash dioxin removal to achieve near-zero emission of solid-phase dioxins, it has high requirements for atmosphere, heat source and tail gas disposal, and there is currently no efficient in-situ low-temperature thermal decomposition technology.

[0027] Therefore, the inventors innovatively propose a fly ash dioxin intelligent integrated collaborative processing system, which realizes one-step dust and solid-phase dioxin removal in the dust collector ash hopper, ensures the non-oxidizing nature of the flue gas and the temperature stability of the thermal decomposition system through a nitrogen source and a smart control module, ensures the transfer of fly ash on demand by arranging a low-temperature thermal decomposition module based on height difference and setting a transportation pipeline, sets the gradient capacity disposal balance system operating power according to the fly ash temperature gradient, and simultaneously utilizes the original waste heat of fly ash to achieve efficient low-temperature thermal decomposition of dioxins in situ, and to achieve near-zero emission of solid-phase dioxins by burning residual components through secondary combustion in the waste incinerator.

[0028] (1) Efficient low-temperature thermal decomposition of dioxins

[0029] Dioxins in fly ash are mainly adsorbed on active carbon particles contained therein. When fly ash is heated, complex chemical reactions such as physical desorption, oxidation degradation and resynthesis of dioxins in fly ash occur. In the process of degrading dioxins in fly ash by low-temperature thermal decomposition, -OH continuously replaces Cl in the dioxin molecule, and the dioxin molecule is oxidized to generate CO2, accompanied by the breaking of C-Cl bonds and the formation of a small amount of C-O-C structure. CaO contained in fly ash is an active substance for the dechlorination / condensation reaction of dioxins, and transition metals such as Cu are catalysts for the dechlorination reaction of dioxins, so that chlorine elements are finally mainly formed into inorganic chlorine salts. At the same time, by controlling the non-oxidizing atmosphere, the resynthesis process of dioxins is inhibited.

[0030] Since large devices are difficult to agitate fly ash significantly, the carrier gas cannot fully carry away the pollution gas. The vertical arrangement of the double-shaft spiral stirring mechanism in the present application can fully drive the fly ash in the device to move in an upward trend, greatly enhancing the agitation in combination with the downward trend of the fly ash itself, so that the pollution gas can be carried away in time and the low-temperature thermal decomposition reaction is promoted. At the same time, the design of the fly ash guide plate makes the space above the module large and the space below the module small, which, in combination with the upward movement trend of the fly ash, improves the uniformity of fly ash distribution and optimizes the internal temperature field. Furthermore, the in-situ treated fly ash particles are fine and have strong reactivity, which is beneficial to the decomposition of dioxins.

[0031] (2) Improve multiple efficiencies through gradient disposal

[0032] The application innovatively proposes that a plurality of cloth bag dust removal modules and respective supporting low-temperature thermal decomposition modules are arranged in series to simultaneously realize gradient treatment of flue gas and fly ash. The design scheme is mainly based on the following two technical purposes:

[0033] First, the continuous series arrangement of a plurality of cloth bag dust removal modules improves the fly ash interception efficiency and gas passing efficiency. The fly ash in the flue gas can pass through the preceding cloth bag dust removal module in a flow-through manner when continuously passing through a plurality of cloth bag dust removal modules, so as to prevent the pressure from rising too fast due to the inability to filter out in a short time. Moreover, the less fly ash contained in the flue gas, the higher the separation efficiency, thereby improving the fly ash interception efficiency and gas passing efficiency as a whole. If a plurality of cloth bag dust removal modules are simply arranged in parallel in the flue duct, serious cloth bag blockage will occur in each cloth bag dust removal module after long-term operation, affecting the overall dust removal effect and ventilation efficiency.

[0034] Secondly, the amount of fly ash adsorbed and settled in the plurality of cloth bag dust removal modules arranged in series differs in the order of the cloth bag dust removal modules. That is, the earlier the low-temperature thermal decomposition module, the more fly ash it receives, and the later the less fly ash it receives. On the basis of this fact, the application proposes a unique design of sequentially connecting the low-temperature thermal decomposition modules to form a continuous gradient treatment process. In the earlier low-temperature thermal decomposition module, due to the large amount of fly ash received, the fly ash exceeding the set receiving amount will be continuously discharged to the next low-temperature thermal decomposition module through the transportation pipeline during production, and so on. By controlling the fly ash discharge speed at the bottom of each low-temperature thermal decomposition module, the overloaded module can be connected to the next module for treatment. By controlling the capacity proportion of different low-temperature thermal decomposition modules, the fly ash decomposition amount in each module can be uniform, thereby achieving the purpose of comprehensively improving the dioxin decomposition efficiency of fly ash.

[0035] (3) Intelligent control:

[0036] The intelligent control module automatically controls the fly ash discharge port electric control valve of the cloth bag dust removal module to realize batch treatment of fly ash, reduce energy consumption, prevent overloading of the cloth bag dust removal module and the low-temperature thermal decomposition module, improve the overall treatment efficiency, and ensure the safety of operation and the continuity of equipment operation.

[0037] The intelligent control module automatically controls the fly ash discharge port electric control valve of the cloth bag dust removal module to realize batch treatment of fly ash, reduce energy consumption, prevent overloading of the cloth bag dust removal module and the low-temperature thermal decomposition module, improve the overall treatment efficiency, and ensure the safety of operation and the continuity of equipment operation.

[0038] The intelligent control module automatically regulates the temperature field of the low-temperature thermal decomposition module, adjusts the temperature of the heater, the rotating speed of the double-shaft spiral stirring mechanism and the nitrogen flow rate through PID self-adaptive adjustment, realizes full-range temperature control of the fly ash, prevents over-high temperature caking while avoiding over-low temperature internal dioxin inefficient decomposition, improves the disposal efficiency of the low-temperature thermal decomposition device, prolongs the service life of the device, and ensures the stability of the disposal process.

[0039] The intelligent control module automatically monitors the oxygen concentration of the low-temperature thermal decomposition module, ensures the internal airtightness and reducing atmosphere of the device, improves the dioxin decomposition efficiency of the device, and ensures the efficiency of the disposal.

[0040] The intelligent control module automatically regulates the fly ash outlet switch of the low-temperature thermal decomposition module, ensures that the fly ash in the low-temperature thermal decomposition module is discharged into the fly ash storage equipment in time after realizing dioxin decomposition, and ensures continuous operation of the device.

[0041] (4) In-situ and modular treatment:

[0042] ①Realize in-situ disposal of solid-phase dioxin. In the conventional treatment scheme, fly ash is directly transported out of the plant, which has environmental risks and increases the total disposal cost. There is a risk of dioxin emission in the transportation and subsequent disposal links. Since the fly ash temperature of the dust collector is about 150-180℃, the conventional fly ash transportation method will cause a large amount of waste of fly ash waste heat after being cooled to room temperature. The present application innovatively proposes to directly assemble the low-temperature thermal decomposition module below the fly ash outlet of each bag-type dust collector module, which can realize the full recovery of fly ash waste heat. The spiral fly ash guide plate prevents wall fly ash adhesion, reduces the risk of caking, and avoids energy consumption and environmental risks in the storage and transportation process. The decomposed tail gas is directly sent into the furnace using inert carrier gas, which utilizes the existing incineration conditions and tail gas disposal equipment, completely avoids the secondary pollution problem of dioxin in the thermal desorption tail gas, reduces the equipment expenditure of the secondary combustion chamber and the activated carbon adsorption device, and has obvious environmental and economic advantages.

[0043] ②The device has high airtightness. The internal structure of a large thermal decomposition device is complex, and it is easy to produce air leakage points, which reduces the dioxin decomposition efficiency. The present application adopts a low-temperature thermal decomposition module, which is closed at the upper and lower ends when working, has few internal connecting structures, and has small air leakage. Through high-precision sealing elements and an intelligent control module, the device can maintain high airtightness during operation, effectively decompose internal dioxin, and allow periodic inspection and replacement of sealing elements of single modules, enhancing the stability of long-term operation of the device.

[0044] ③Prevent caking. When low-temperature thermal decomposition is performed, fly ash has a caking problem. The generation of caking makes the wrapped particles unable to fully contact the carrier gas, severely reduces the thermal decomposition efficiency and can cause plugging problems. Directly collecting fly ash after dust removal for low-temperature thermal decomposition can minimize the water absorption of fly ash, keep it in a fine particle state, and improve the reactivity. Furthermore, large-scale low-temperature thermal decomposition devices usually use wall heating. In order to ensure that the temperature in the device reaches the required temperature, the outer wall temperature of the device is often much higher than the temperature inside the device, which causes the fly ash near the wall to have a temperature that is too high (>580℃) and is prone to caking. The conventional large-scale thermal decomposition device can dispose of a large amount of fly ash at one time. The low-temperature thermal decomposition device with in-situ modular design has a size of only 1 / 10 of the conventional device, and the single disposal amount is small. The fly ash can be disposed in groups, each module is independently controlled, and the temperature conditions are precisely controlled through the intelligent control system to realize the synchronous operation of multiple modules. Finally, the small modular device can continuously stir all the fly ash through the double-shaft screw stirring device, and the temperature field is uniformized through the design of the fly ash guide plate, further avoiding the generation of caking problems.

[0045] ④Energy saving and carbon reduction. In the bag dust removal module, the temperature of fly ash decreases along the airflow direction. Due to the temperature difference of fly ash falling into each low-temperature thermal decomposition module, the fly ash gradient classification low-temperature thermal decomposition system is set with the capacity ratio of gradient reduction as the critical value. For example, the fly ash is transported to each low-temperature thermal decomposition module through the transportation pipeline with a mass gradient of 5%, which balances the operating power of each low-temperature thermal decomposition module, optimizes the energy distribution in the system, prolongs the service life of the equipment, and realizes the efficient disposal of fly ash on demand.

[0046] ⑤Realize individualized installation. The conventional thermal decomposition device is an integrated structure, which has high installation and modification costs, and adopts a unified disposal process for fly ash from different power plants, which is difficult to adapt to the needs of different fly ash. The modular design of the dioxin in-situ rapid detoxification intelligent integrated disposal system facilitates the disassembly and modification of the equipment, and can be customized and used according to the fly ash sticking characteristics and the bag cleaning pressure difference of different power plants, greatly improving the adaptability and economy of the device. At the same time, the modules of the device can be freely combined and controlled, which is suitable for fly ash disposal of different scales and meets the diversified processing needs.

[0047] In summary, by using the new system to low-temperature thermal decompose the fly ash solid-phase dioxin in the waste incineration power plant, the near-zero emission of dioxin can be realized. The present application can continuously heat the fly ash at 300-400℃, control the dioxin content to be less than 20 ng·TEQ / kg, and achieve a removal rate of more than 95%. Compared with the disposal of solid-phase dioxin by downstream enterprises, the consumption of the transportation link is saved, the energy, equipment and land costs are reduced, the dioxin disposal efficiency is high, the decomposition is complete, there is no tail gas pollution risk, and the environmental risk is greatly reduced.

[0048] Compared with the prior art, the application has the following advantages:

[0049] (1) The application can realize in-situ efficient low-temperature thermal decomposition of fly ash dioxin, realize rapid detoxification of fly ash, reduce process energy consumption and environmental risk, and realize near-zero emission of waste incineration power plants;

[0050] (2) The application can realize gradient treatment of flue gas and fly ash by respectively connecting the bag dust removal module and the matching low-temperature thermal decomposition module. The former improves the fly ash interception efficiency and gas passing efficiency as a whole, and the latter controls the fly ash capacity ratio in different low-temperature thermal decomposition modules to realize the coordination and unity of fly ash decomposition amount and temperature in each module, avoid power overload of the front module and surplus of the rear module, and realize efficient treatment of fly ash on demand.

[0051] (3) The application can realize effective regulation and control of low-temperature thermal decomposition temperature field and reducing atmosphere through intelligent control, ensure the treatment efficiency of the device, avoid fly ash caking, improve the safety of the device and the resource utilization efficiency of fly ash;

[0052] (4) The application modularly processes the system, and designs or transforms the bag dust removal system to improve the sealing of the device, reduce the system occupation, and realize cost reduction and efficiency increase through structure updating;

[0053] (5) The application cancels the design of the fly ash storage chamber and transportation equipment in the traditional device, reduces the equipment installation, operation and transportation cost, improves the utilization efficiency of fly ash in-situ heat energy and kinetic energy, saves energy, and reduces carbon emission. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 The figure is a schematic diagram of the system of the application.

[0055] Figure 2 The figure is a structural schematic diagram of the bag dust removal module.

[0056] Figure 3 The figure is a structural schematic diagram of the low-temperature thermal decomposition module.

[0057] Figure 4 The figure is a low-temperature thermal decomposition module arranged in a step-down manner.

[0058] Figure 5 The figure is a schematic diagram of the intelligent control module.

[0059] The figure mark: cloth bag dust removal module 1, low temperature thermal decomposition module 2, wisdom control module 3, fly ash storage container 4, filter 5, induced draft fan 6, hearth 7, flue 8, nitrogen source 9, pulse valve 11, air inlet 12, air outlet 13, differential pressure sensor 14, ash bucket 15, spiral ash guide plate 16, ash outlet 17, ash inlet 21, nitrogen inlet 22, double-shaft spiral stirring mechanism 23, tail gas discharge port 24, ash content meter 25, heater 26, temperature sensor 27, ash guide plate 28, oxygen sensor 29, ash discharge port 30, ash equalization pipe 31, ash guide piece 32, man-machine dialogue interface 33, main control board 34. DETAILED DESCRIPTION

[0060] First of all, it should be pointed out that the present application relates to the field of solid waste incineration pollution disposal, and is a fly ash dioxin in-situ rapid detoxification intelligent integrated disposal system of a waste incineration plant. In the implementation process of the present application, processes such as dust removal, ash discharge, heat exchange and fly ash storage will be involved, and production equipment including but not limited to bag-type dust collector, automatic valve and pulse spraying equipment will be involved. The above related processes belong to the prior art, and the person skilled in the art can operate the corresponding equipment skillfully. Whatever is mentioned in the application file of the present application belongs to this category, and the applicant will not list it one by one.

[0061] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with the drawings and specific embodiments. The fly ash dioxin content before and after disposal of each embodiment is shown in Table 1. Obviously, the embodiments are only the most basic embodiments of the present application, not all embodiments. Based on other embodiments of the present application, they all belong to the scope of protection of the present application.

[0062] As shown in Figure 1 The fly ash dioxin in-situ rapid detoxification intelligent integrated disposal system of a waste incineration plant provided by the present application includes a cloth bag dust removal module 1 arranged on a flue 8, and a matched low temperature thermal decomposition module 2, wisdom control module 3 and fly ash storage container 4. The cloth bag dust removal module 1 has multiple and is arranged in series. The hearth 7 is connected to the air inlet 12 of the first cloth bag dust removal module 1 through the flue 8. The adjacent cloth bag dust removal modules 1 are connected in series by pipelines to realize continuous air inlet. The air outlet 13 at the top of each cloth bag dust removal module 1 is connected to a tail gas treatment unit.

[0063] As shown in Figure 2As shown, the cloth bag dust removal module 1 has a hollow cavity, which is divided into two parts by a top partition; a plurality of vertical hollow cloth bags are installed on the partition with their open ends, and a differential pressure sensor is arranged on both sides of the partition; a backflushing pipe is arranged in each cloth bag, and the backflushing pipes are connected to a gas inlet pipe provided with a pulse valve; the lower part of the cavity is a dust hopper 15 in the shape of an inverted cone, a spiral dust guide plate 16 is arranged on the inner wall thereof, and the fly ash moves downward along the spiral in a fast spiral motion relying on its own gravity and pulse backflushing force. A dust amount meter is arranged on the upper edge of the dust hopper, and a dust outlet 17 is located at the bottom of the dust hopper 15. A low-temperature thermal decomposition module 2 is arranged at the bottom of each cloth bag dust removal module 1, and is connected to each other through the dust outlet 17 and a dust inlet 21, and an electric control valve is arranged at the dust outlet 17. Each cloth bag dust removal module 1 is provided with a parallel pipeline for introducing flue gas, and a matching valve is arranged on the parallel pipeline and the pipeline connecting adjacent modules; by switching the valve, the flue gas can pass through a certain module that is short-circuited, so that the system can continue to operate.

[0064] As shown in Figure 3 The low-temperature thermal decomposition module 2 is arranged vertically and has a hollow cavity, a stirring mechanism is arranged in the cavity, and a heater 26 is arranged outside the cavity; a nitrogen gas inlet 22 is arranged in the lower part of the cavity, and a tail gas discharge port 24 is arranged at the top of the cavity; a uniform material port is arranged on the side of each adjacent low-temperature thermal decomposition module 2, and the uniform material ports are connected through a uniform dust pipe 31, and an electric control valve is arranged at the uniform material port; a dust guide plate 32 is arranged in the uniform dust pipe 31, and the upper surface of the dust guide plate 32 is parallel to the direction of the pipeline. A dust discharge port 30 is arranged at the bottom of the cavity of each low-temperature thermal decomposition module 2, and is connected to a fly ash storage container 4 through a pipeline, and an electric control valve is arranged at the dust discharge port 30. The nitrogen gas inlet 22 of the low-temperature thermal decomposition module 2 is connected to a nitrogen source 9 (such as a nitrogen tank or an air separation device) through a pipeline, a flow meter is arranged on the pipeline, and the flow meter is connected to a main control board 34 in the intelligent control module 3 through a cable. A conical dust guide plate 28 is arranged in the cavity of the low-temperature thermal decomposition module 2, or at least two inclined dust guide plates 28 are arranged in the cavity, forming an enclosed area with a large upper end and a small lower end, and the stirring mechanism is located in the center of the enclosed area. The tail gas discharge ports 24 at the top of each low-temperature thermal decomposition module 2 are connected to a discharge pipe through a pipeline, and the discharge pipe is sequentially connected to a filter 5, an induced draft fan 6, and an air inlet of a furnace 7.

[0065] As an option, the two pressure points of the differential pressure sensor 14 are arranged at the air inlet 12 and the air outlet 13 on both sides of the partition in the bag-type dust collector. The stirring mechanism is a double-shaft spiral stirring structure 23, the paddle cross section of which gradually increases from bottom to top, the blade angle is the same as the inclination angle of the ash guide plate 28 and maintains a spacing; the rotating directions of the blades on the two shafts are opposite, so that the stirred fly ash can move upward, and the fly ash is uniformly distributed. The temperature sensor 27 is multiple, which is respectively arranged on the shaft of the stirring mechanism and the inner wall of the cavity; the heater 26 is an electric heater or a flue gas heat exchanger; the electric heater is connected with the power device of the garbage incineration plant through a cable, and the flue gas heat exchanger is connected with the flue of the garbage incineration furnace through a pipeline. The ash content meter 25 is arranged on the inner wall of the cavity below the exhaust gas discharge port 24.

[0066] As shown in Figure 4 , each low-temperature thermal decomposition module 2 can be arranged in turn with the position of the bag-type dust collection module 1, and arranged in a step-down manner; the uniform ash pipe 31 between the uniform ash outlet of the rear-stage low-temperature thermal decomposition module 2 and the ash outlet of the front-stage low-temperature thermal decomposition module 2 is arranged obliquely and forms an angle with the horizontal direction.

[0067] As shown in Figure 5 , the intelligent control module 3 includes a man-machine dialogue interface 33 (such as a liquid crystal display) and a main control board 34, the main control board 34 is connected with the differential pressure sensor 14 and the ash content meter arranged in the bag-type dust collection module 1, the ash content meter 25, the temperature sensor 27 and the oxygen sensor 29 arranged in the low-temperature thermal decomposition module 2, and the temperature control equipment of the heater 28, the speed regulator of the stirring mechanism, the electric control valve arranged at the ash outlet 17, the uniform ash outlet and the ash discharge port 30 through cables respectively.

[0068] The intelligent control module 3 identifies the pressure difference between the air inlet and the air outlet of the cloth bag dust removal module through the differential pressure sensor 14, and starts the system control strategy according to the preset control scheme. The intelligent control module 3 receives data from the temperature sensor 27 on the wall surface of the low-temperature thermal decomposition module 2 and the shaft of the double-helix stirring mechanism 23, which is used to calculate the temperature field in the device, and then automatically adjusts the working state of the heater 28, the rotating speed of the double-shaft helical stirring mechanism 23 and the nitrogen flow through the PID control system, while controlling the minimum temperature and the maximum temperature in the low-temperature thermal decomposition module 2 to meet the requirements of the control strategy. The intelligent control module 3 automatically controls the opening and closing of the electric control valves at each ash outlet 17, the material distribution port and the ash discharge port 30 through the data from the ash content meter in the cloth bag dust removal module 1 and the low-temperature thermal decomposition module 2. The man-machine dialogue interface 33 (such as a liquid crystal display) in the intelligent control module 3 can display the pressure difference of the cloth bag dust removal module 1, the oxygen concentration in the low-temperature thermal decomposition module 2, the heating time of the heater 28, the rotating speed of the double-shaft helical stirring mechanism 23, the nitrogen flow, the wall surface and double-shaft helical stirring mechanism axial temperature transmitted by each temperature sensor 27, and the data transmitted by each sensor is used to make autonomous calculation according to the predetermined control strategy to realize the control decision of the temperature field and the fly ash disposal.

[0069] As a common sense that can be understood by those skilled in the art, the master control board described in the present application is essentially a computer device, which includes a memory configured to store instructions, and a processor configured to call the instructions from the memory and enable the implementation of the garbage incineration plant fly ash dioxin in-situ rapid detoxification intelligent integrated disposal method in the present application when executing the instructions. At the same time, the master control board also includes a computer readable storage medium, which stores instructions for causing the computer device to execute the method. As an example, the computer device can be a personal computer, a server, or a network device, etc., and the computer storage medium can include various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0070] Based on the device with the above innovative structure, the present application realizes the garbage incineration plant fly ash dioxin in-situ rapid detoxification intelligent integrated disposal method, which specifically includes:

[0071] (1) When the initial use, if the pressure difference in the bag filter module 1 reaches the set value, nitrogen is introduced into the low-temperature thermal decomposition module 2, the heater 28 and the induced draft fan 6 are started; when the pressure difference in the bag filter module 1 further increases to the preset value, the electric control valve of the ash outlet 17 is opened according to the set time length, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module 2; after the electric control valve is closed, the stirring structure is started, and the reaction temperature in the low-temperature thermal decomposition process is controlled to be 300-400℃;

[0072] (2) Since the fly ash in the flue gas continuously accumulates in the bag filter module 1 during the production process, the electric control valve needs to be opened for fly ash discharge operation according to the detection signal of the ash amount meter; if the signal of the ash amount meter 25 in the low-temperature thermal decomposition module 2 is detected, the electric control valve of the uniform ash pipe 31 between the current low-temperature thermal decomposition module 2 and the next low-temperature thermal decomposition module 2 is opened, so that the excess fly ash enters the next low-temperature thermal decomposition module 2 from the uniform ash pipe 31; the ash amount control and discharge operation of each stage of the bag filter module 1 and the ash amount control and excess ash release in the low-temperature thermal decomposition module 2 are executed in this way;

[0073] (4) Nitrogen is continuously input during the low-temperature thermal decomposition process, the generated tail gas is filtered and sent back to the furnace 7 by the induced draft fan 6, and the harmful components generated in the thermal decomposition process are eliminated by combustion; after the fly ash stays for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash outlet 30 is opened, and the treated fly ash is discharged into the fly ash storage container 4.

[0074] The application innovatively proposes that the amount of fly ash in each low-temperature thermal decomposition module is controlled to have a gradient decrease trend, and the amount of fly ash in the module of the next stage is less than that in the module of the previous stage. For example, the ash amount control in the first module is 85% of the total volume of the inner cavity, and the ash amount control in the subsequent modules is decreased by 5% successively. During the treatment process of low-temperature thermal decomposition, the nitrogen gas inlet flow rate in each low-temperature thermal decomposition module is controlled to be 1-5 L / min, the oxygen concentration is less than 0.5%, the stirring speed is 3-20 r / min, and the reaction time is 0.5-1 h.

[0075] Example 1

[0076] As an example, the heater is selected as an electric heat exchanger.

[0077] The fly ash dioxin in-situ efficient treatment method of the embodiment is specifically as follows:

[0078] (1) Automatic control is realized through the intelligent control module; when the display screen displays that the pressure difference in the bag filter module reaches 1500 Pa, the gas inlet of the low-temperature thermal decomposition module is opened, the nitrogen source, the heater and the induced draft fan are started, the main control board controls the nitrogen flow rate to be 1 L / min, the oxygen concentration to be 0.1%, and the average temperature in the low-temperature thermal decomposition module to be 350℃;

[0079] (2) Through the wisdom control module automatic control, when the pressure difference sensor shows the cloth bag dust collector module pressure difference reaches 1600Pa, start dioxin in situ rapid detoxification intelligent integrated disposal system, open fly ash collection module ash outlet, make fly ash fall into low temperature thermal decomposition module, 2min later, close fly ash collection module ash outlet and low temperature thermal decomposition device ash inlet;

[0080] (3) Through the wisdom control module automatic control, when the ash content meter 1 shows that the fly ash amount in the first low temperature thermal decomposition module reaches 85%, open the uniform material ash outlet 1 and the uniform material ash inlet 2, when the ash content meter 1 shows that the fly ash amount is 80%, close the uniform material ash outlet 1, and close the uniform material ash inlet 2 after 10s, when the ash content meter 2 shows that the fly ash amount in the second low temperature thermal decomposition module reaches 80%, open the uniform material ash outlet 2 and the uniform material ash inlet 3, when the ash content meter 2 shows that the fly ash amount is 75%, close the uniform material ash outlet 2, and close the uniform material ash inlet 3 after 10s, when the ash content meter 3 shows that the fly ash amount in the third low temperature thermal decomposition module reaches 75%, open the uniform material ash outlet 3 and the uniform material ash inlet 4, when the ash content meter 3 shows that the fly ash amount is 70%, close the uniform material ash outlet 3, and close the uniform material ash inlet 4 after 10s, ensure that the fly ash amount in the low temperature thermal decomposition module arranged in sequence is uniform;

[0081] (4) Through the wisdom control module automatic control, when the fly ash begins to fall into the low temperature decomposition module, start the double helix stirring mechanism, the main control board controls the stirring speed to be 3r / min, the nitrogen flow is 1L / min, and lasts for 30min, so that the average temperature fed back by the temperature sensor is taken as the feedback point, 350℃ is taken as the reference value, the heater temperature, the double helix stirring mechanism stirring speed and the nitrogen flow are regulated and controlled through the PID control system, so that the fly ash temperature field temperature can be stably controlled between 300~400℃, and the tail gas enters the furnace for secondary combustion through the induced draft fan;

[0082]

[0083] In the formula,

[0084] Heater temperature: K p,heat =1.0, K i,heat =0.1, K d,heat =0.5

[0085] Nitrogen flow: K p,N2 =0.5, K i,N2 =0.05, K d,N2 =0.3

[0086] Stirring speed: K p,stir =0.8, K i,stir =0.08, K d,stir =0.4

[0087] (5) After the low-temperature thermal decomposition is completed, the dioxin in-situ rapid detoxification intelligent integrated disposal system is stopped, the ash outlet of the low-temperature thermal decomposition module is opened, the fly ash is made to enter the fly ash collection and storage equipment through the ash outlet, and the dioxin detoxification fly ash with a dioxin toxicity equivalent of 8.7 ng-TEQ / kg is obtained.

[0088] Example 2

[0089] As an example scheme, the heater is selected as a flue gas heat exchanger.

[0090] The fly ash dioxin in-situ efficient disposal method of the embodiment is specifically:

[0091] (1) Automatic control through the intelligent control module, when the display screen displays that the pressure difference in the bag-type dust collector module reaches 1500 Pa, the gas inlet of the low-temperature thermal decomposition module is opened, the nitrogen source, the heater and the induced draft fan are started, the nitrogen flow is controlled by the main control board to be 1 L / min, the oxygen concentration is 0.3%, and the average temperature in the low-temperature thermal decomposition module is 400℃;

[0092] (2) Automatic control through the intelligent control module, when the pressure difference sensor displays that the pressure difference in the bag-type dust collector module reaches 1800 Pa, the dioxin in-situ rapid detoxification intelligent integrated disposal system is started, the ash outlet of the fly ash collection module is opened, the fly ash falls into the low-temperature thermal decomposition module, after 5 min, the ash outlet of the fly ash collection module and the ash inlet of the low-temperature thermal decomposition device are closed;

[0093] (3) Automatic control through the intelligent control module, when the ash amount meter 1 displays that the fly ash amount in the first-stage low-temperature thermal decomposition module reaches 85%, the uniform material ash outlet 1 and the uniform material ash inlet 2 are opened, when the ash amount meter 1 displays that the fly ash amount is 80%, the uniform material ash outlet 1 is closed, and the uniform material ash inlet 2 is closed after 10 s, when the ash amount meter 2 displays that the fly ash amount in the second-stage low-temperature thermal decomposition module reaches 80%, the uniform material ash outlet 2 and the uniform material ash inlet 3 are opened, when the ash amount meter 2 displays that the fly ash amount is 75%, the uniform material ash outlet 2 is closed, and the uniform material ash inlet 3 is closed after 10 s, when the ash amount meter 3 displays that the fly ash amount in the third-stage low-temperature thermal decomposition module reaches 75%, the uniform material ash outlet 3 and the uniform material ash inlet 4 are opened, when the ash amount meter 3 displays that the fly ash amount is 70%, the uniform material ash outlet 3 is closed, and the uniform material ash inlet 4 is closed after 10 s, so that the fly ash amounts in the sequentially arranged low-temperature thermal decomposition modules are uniform;

[0094] (4) By intelligent control module automatic control, when the fly ash begins to fall into the low-temperature decomposition module, start the double helix stirring mechanism, the main control panel controls the stirring speed to be 20 r / min, the nitrogen flow rate is 5 L / min, and lasts for 1 h, so that the average temperature fed back by the temperature sensor is taken as a feedback point, 350℃ is taken as a reference value, the heater temperature, the double helix stirring mechanism stirring speed and the nitrogen flow rate are regulated and controlled through the PID control system, and the fly ash temperature field temperature can be stabilized between 300-400℃, and the tail gas enters the furnace for secondary combustion through the induced draft fan;

[0095]

[0096] In the formula,

[0097] Heater temperature: K p,heat = 1.0, K i,heat = 0.1, K d,heat = 0.5

[0098] Nitrogen flow rate: K p,N2 = 0.5, K i,N2 = 0.05, K d,N2 = 0.3

[0099] Stirring speed: K p,stir = 0.8, K i,stir = 0.08, K d,stir = 0.4

[0100] (5) After the low-temperature thermal decomposition is completed, the dioxin in-situ rapid detoxification intelligent integrated disposal system is stopped, the ash outlet of the low-temperature thermal decomposition module is opened, the fly ash enters the fly ash storage equipment through the ash outlet, and the dioxin detoxification fly ash with a dioxin toxicity equivalent of 8.7 ng-TEQ / kg is obtained.

[0101] Example 3

[0102] As an example scheme, the heater is selected as an electric heat exchanger.

[0103] The fly ash dioxin in-situ efficient disposal method of the embodiment is specifically:

[0104] (1) By the intelligent control module automatic control, when the display screen displays that the pressure difference in the bag-type dust collector module reaches 1500 Pa, the gas inlet of the low-temperature thermal decomposition module is opened, the nitrogen source, the heater and the induced draft fan are started, the main control panel controls the nitrogen flow rate to be 1 L / min, the oxygen concentration is 0.2%, and the average temperature in the low-temperature thermal decomposition module is 300℃;

[0105] (2) Through the wisdom control module automatic control, when the pressure difference sensor shows the cloth bag dust collector module pressure difference reaches 1700Pa, start dioxin in situ rapid detoxification intelligent integrated disposal system, open fly ash collection module ash outlet, make fly ash fall into low temperature thermal decomposition module, 3min later, close fly ash collection module ash outlet and low temperature thermal decomposition device ash inlet;

[0106] (3) Through the wisdom control module automatic control, when the ash content meter 1 shows that the fly ash amount in the first low temperature thermal decomposition module reaches 85%, open the uniform material ash outlet 1 and the uniform material ash inlet 2, when the ash content meter 1 shows that the fly ash amount is 80%, close the uniform material ash outlet 1, and close the uniform material ash inlet 2 after 10s, when the ash content meter 2 shows that the fly ash amount in the second low temperature thermal decomposition module reaches 80%, open the uniform material ash outlet 2 and the uniform material ash inlet 3, when the ash content meter 2 shows that the fly ash amount is 75%, close the uniform material ash outlet 2, and close the uniform material ash inlet 3 after 10s, when the ash content meter 3 shows that the fly ash amount in the third low temperature thermal decomposition module reaches 75%, open the uniform material ash outlet 3 and the uniform material ash inlet 4, when the ash content meter 3 shows that the fly ash amount is 70%, close the uniform material ash outlet 3, and close the uniform material ash inlet 4 after 10s, ensure that the fly ash amount in the low temperature thermal decomposition module arranged in sequence is uniform;

[0107] (4) Through the wisdom control module automatic control, when the fly ash begins to fall into the low temperature decomposition module, start the double helix stirring mechanism, the main control board controls the stirring speed to be 10r / min, the nitrogen flow is 3L / min, and lasts for 45min, so that the average temperature fed back by the temperature sensor is taken as the feedback point, 350℃ is taken as the reference value, the heater temperature, the double helix stirring mechanism stirring speed and the nitrogen flow are regulated and controlled through the PID control system, so that the fly ash temperature field temperature can be stably controlled between 300~400℃, and the tail gas enters the furnace for secondary combustion through the induced draft fan;

[0108]

[0109] In the formula,

[0110] Heater temperature: K p,heat =1.0, K i,heat =0.1, K d,heat =0.5

[0111] Nitrogen flow: K p,N2 =0.5, K i,N2 =0.05, K d,N2 =0.3

[0112] Stirring speed: K p,stir =0.8, K i,stir =0.08, K d,stir =0.4

[0113] (5) After the low-temperature thermal decomposition is completed, the intelligent in-situ rapid detoxification disposal system of dioxin is stopped, the ash outlet of the low-temperature thermal decomposition module is opened, the fly ash enters the fly ash collecting and storing equipment through the ash outlet, and the detoxified fly ash with a dioxin toxicity equivalent of 9.3 ng-TEQ / kg is obtained.

[0114] Table 1: Fly ash dioxin content before and after disposal

[0115] Item Example 1 Example 2 Example 3 Pre-treatment / (ng TEQ / kg) 553 604 378 Post-treatment / (ng TEQ / kg) 8.7 10.6 9.3 Removal / % 98.4 98.3 97.2

[0116] The above are specific embodiments of the present application. Obviously, those skilled in the art can make various applications, supplements, modifications and changes to the present application without departing from the spirit and scope of the present application. If the various applications, supplements, modifications and changes based on the present application fall within the scope of the claims of the present application and the equivalent technology, the present application also intends to include these applications, supplements, modifications and changes.

Claims

1. A waste incineration plant fly ash dioxin in-situ rapid detoxification intelligent integrated disposal system, characterized in that, The application relates to a bag dust removal module arranged on a flue, and a matched low-temperature thermal decomposition module, a fly ash collecting and storing container and a smart control module. The bag dust removal module is arranged in series, the flue is connected to the air inlet of the first module, the modules are connected in series through pipelines, the air outlets of the modules are connected to a tail gas treatment unit, and the low-temperature thermal decomposition modules are arranged at the bottoms of the bag dust removal modules and connected through ash outlets and ash inlets. The low-temperature thermal decomposition module has a hollow cavity, a stirring mechanism is arranged in the cavity, and a heater is arranged outside the cavity; a nitrogen gas inlet is arranged at the lower part of the cavity, and a tail gas discharge port is arranged at the top of the cavity; the side parts of the adjacent low-temperature thermal decomposition modules are each provided with a material equalizing port and connected through a pipeline, and an electric control valve is arranged at the material equalizing port; the bottoms of the cavities of the modules are provided with ash discharge ports and connected to the fly ash collecting and storing container through pipelines, and an electric control valve is arranged at the ash discharge port. The smart control module comprises a man-machine dialogue interface and a main control board, and the main control board is connected to a differential pressure sensor and an ash content meter arranged in the bag dust removal module, an ash content meter, a temperature sensor and an oxygen sensor arranged in the low-temperature thermal decomposition module, a temperature control device of the heater, a speed regulator of the stirring mechanism and the electric control valves arranged at the ash outlets, the material equalizing ports and the ash discharge ports through cables.

2. The system of claim 1, wherein, The bag dust removal module has a hollow cavity, which is divided into two parts by a top partition; a plurality of vertical hollow bags are arranged on the partition with their open ends, and differential pressure sensors are arranged on both sides of the partition; a back flushing pipe is arranged in each bag, and the back flushing pipes are connected to an air inlet pipe provided with a pulse valve; the lower part of the cavity is a reverse cone-shaped ash hopper, a spiral ash guide plate is arranged on the inner wall of the ash hopper, and an ash content meter is arranged on the upper edge of the ash hopper, and an ash outlet is arranged at the bottom of the ash hopper.

3. The system of claim 1, wherein, Each bag dust removal module is provided with parallel pipelines for introducing flue gas, and matched valves are arranged on the parallel pipelines and the pipelines connecting adjacent modules; by switching the valves, the flue gas can pass through a certain module which is short-circuited, and the system can continuously run.

4. The system of claim 1, wherein, The nitrogen gas inlet of the low-temperature thermal decomposition module is connected to a nitrogen source through a pipeline, a flow meter is arranged on the pipeline, and the flow meter is connected to the main control board through a cable; the temperature sensor has a plurality of temperature sensors arranged on the shaft of the stirring mechanism and the inner wall of the cavity; the heater is an electric heater or a flue gas heat exchanger; and the ash content meter is arranged on the inner wall of the cavity below the tail gas discharge port.

5. The system of claim 1, wherein, The cavity of the low-temperature thermal decomposition module is provided with a conical ash guide plate, or at least two inclined ash guide plates are arranged in the cavity to form an enclosed area with a large upper end and a small lower end, and the stirring mechanism is arranged in the center of the enclosed area; the stirring mechanism is a double-shaft spiral stirring structure, the paddle cross section of the stirring structure gradually increases from bottom to top, and a distance is kept between the paddle cross section and the ash guide plate; the rotating directions of the blades on the two rotating shafts are opposite, so that the stirred fly ash can move upwards.

6. The system of claim 1, wherein, The tail gas discharge ports of the top parts of the low-temperature thermal decomposition modules are connected to a discharge pipe through pipelines, the discharge pipe is sequentially connected to a filter, an induced draft fan and an air inlet of a furnace.

7. The system of claim 1, wherein, The low-temperature thermal decomposition modules are arranged in sequence with the bag-type dust collector modules and are arranged in a step-down manner; the uniform feeding port of the latter module is lower than the uniform feeding port of the former module, and the connecting pipeline between the two is arranged obliquely and forms an angle with the horizontal direction.

8. The intelligent integrated disposal method for dioxin in-situ rapid detoxification of fly ash in waste incineration plant by using the system of claim 1, characterized in that, The method comprises the following steps: (1) when the bag-type dust collector module is first put into use, nitrogen is introduced into the low-temperature thermal decomposition module, the heater and the induced draft fan are started when the pressure difference in the bag-type dust collector module reaches the set value, and when the pressure difference in the bag-type dust collector module further increases to the preset value, the electric control valve of the ash outlet is opened according to the set time length, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module; the electric control valve is closed, and the stirring structure is started to control the reaction temperature in the low-temperature thermal decomposition process to be 300-400℃; (2) since the fly ash in the flue gas continuously accumulates in the bag-type dust collector module during the production process, the electric control valve needs to be opened for fly ash discharge operation according to the detection signal of the ash amount meter; if the ash amount meter signal in the low-temperature thermal decomposition module is detected, the electric control valve of the uniform feeding port between the current low-temperature thermal decomposition module and the next low-temperature thermal decomposition module is opened, so that the excess fly ash enters the next low-temperature thermal decomposition module through the connecting pipeline; the ash amount control and discharge operation of each bag-type dust collector module and the ash amount control and excess fly ash release in the low-temperature thermal decomposition module are executed in the same way; (3) nitrogen is continuously input during the low-temperature thermal decomposition process, the tail gas generated after filtration is sent back to the furnace by the induced draft fan, and the harmful components generated in the thermal decomposition process are eliminated by combustion; after the fly ash stays for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash outlet is opened, and the treated fly ash is discharged into the fly ash storage container.

9. The method of claim 8, wherein, The amount of fly ash in each low-temperature thermal decomposition module is controlled to have a gradient decrease, and the amount of fly ash in the latter module is less than that in the former module.

10. The method of claim 8, wherein, The nitrogen input flow rate in each low-temperature thermal decomposition module is controlled to be 1-5L / min, the oxygen concentration is less than 0.5%, the stirring speed is 3-20r / min, and the reaction time is 0.5-1h.

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