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

Abstract

The invention relates to a hazardous waste treatment technology, and aims to provide an intelligent integrated treatment system for in-situ rapid detoxification of dioxin in fly ash of a waste incineration plant. The system comprises a plurality of bag dust removal modules which are sequentially arranged on a flue in a series connection mode, the adjacent modules are communicated through pipelines to achieve continuous air inlet, and a low-temperature thermal decomposition module is arranged at the bottom of each module. A stirring mechanism is arranged in a cavity of the low-temperature thermal decomposition module, material uniformizing openings are formed in the side portions of the adjacent modules respectively and connected through pipelines, and ash discharging openings are formed in the bottoms of the modules and connected to a fly ash collecting and storing container through pipelines respectively. According to the method, in-situ efficient low-temperature thermal decomposition of fly ash dioxin can be achieved, rapid detoxification of fly ash is achieved, process energy consumption and environmental risks are reduced, and near-zero emission of a waste incineration power plant is achieved; the flue gas and the fly ash can be subjected to gradient treatment at the same time, the fly ash interception and gas passing efficiency is improved on the whole, and the fly ash decomposition amount in each module and the temperature in the module are coordinated and unified.

Description

Technical Field

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

[0002] With the continuous growth of the output of solid waste, especially urban domestic waste, incineration has been increasingly widely used as an effective way to achieve its reduction, resource utilization and harmless treatment. However, the waste incineration process will produce carcinogens such as dioxins, which are usually captured in the solid phase by injecting activated carbon and become part of the fly ash. After being intercepted by the dust collector, the fly ash falls into the ash bin and is then transported to special equipment for detoxification treatment. During the transportation and disposal of fly ash, the residual heat of the fly ash is dissipated in large quantities, and there is a risk of dioxin escape; even if high-temperature treatment is carried out, its tail gas may cause secondary pollution. Therefore, quickly reducing the toxicity of dioxins is an important step in the resource utilization of fly ash.

[0003] Low-temperature thermal decomposition is a technology that heats fly ash at low temperature under non-oxidizing atmosphere conditions to decompose dioxins in fly ash. Compared with high-temperature processes such as cement kiln co-disposal and fly ash melting, the use temperature of low-temperature thermal decomposition is 250-500℃, and the energy consumption is relatively low compared to high-temperature disposal methods. It can also reduce the dioxin content in fly ash by more than 95%, meeting the requirements of the "Technical Specifications for Pollution Control of Fly Ash from Municipal Waste Incineration (Trial)" (HJ 1134) and achieving near-zero emissions of solid-phase dioxins. However, there are environmental risks in the tail gas of low-temperature thermal decomposition, which requires secondary combustion and adsorption disposal, resulting in huge energy consumption and additional costs. Decomposition temperature and reducing atmosphere are the 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 under stable temperature and atmosphere; and the equipment is prone to serious agglomeration problems, which greatly reduces the efficiency of low-temperature thermal decomposition and may also cause blockage or even shutdown. In terms of materials, the existing treatment method involves fly ash storage, transportation and feeding. The waste heat of newly captured fly ash is wasted in large quantities, additional consumption is generated in the intermediate process, and there is a risk of dioxin escape. It is not an ideal method 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, which 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 in the fly ash is dissipated, energy consumption is increased, and there is a risk of dioxin environmental pollution during the transportation process; at the same time, the temperature of the pyrolysis section is controlled by the original DSC automatic control system of the power plant, and real-time control of the internal temperature cannot be achieved, making it difficult to regulate the fly ash to be evenly heated.

[0005] Chinese patent application CN 115488137A discloses a system and method for degrading dioxins in fly ash from garbage incineration, wherein fly ash is transported to a low-temperature thermal decomposition device through a transport device, pyrolyzed at 300-450°C in a nitrogen atmosphere for 1-2 hours, cooled after passing through a cooling device, and the waste gas is passed through a subsequent tail gas treatment unit for treatment. The system has a complex structure, and contains multiple complex units such as a transport device, a low-temperature thermal degradation device, a cooling device, and a product collection device. The unit connection section is prone to air leakage, and it is difficult to ensure a reducing atmosphere for degradation; at the same time, the device continuously and uninterruptedly feeds fly ash into a rotary electric heating low-temperature thermal degradation device, and the temperature of the heating module is only regulated by the fly ash temperature on both sides. It is difficult to ensure uniform internal heating when disposing a large amount of fly ash at one time, and the central temperature control is difficult, the dioxin degradation effect is difficult to ensure, the power consumption is large, the economy is poor, and there is also a risk of dioxin environmental pollution during the transportation process.

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

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an intelligent integrated disposal system and method for in-situ rapid detoxification of dioxins in fly ash from a waste incineration plant.

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

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

[0010] There are multiple bag dust removal modules which are arranged in series. The furnace is connected to the air inlet of the first module through the flue. Adjacent modules are connected by pipelines to achieve continuous air intake. The air outlet on the top of each module is connected to the tail gas treatment unit. A low-temperature thermal decomposition module is set at the bottom of each bag dust removal module, and they are connected through their respective ash outlets and ash inlets. An electric control valve is set at the ash outlet.

[0011] The low-temperature thermal decomposition module has a hollow inner cavity, a stirring mechanism is arranged inside, and a heater is arranged outside; a nitrogen inlet is arranged at the lower middle part of the cavity, and an exhaust gas discharge port is arranged at the top; a material distribution port is arranged at the side of each adjacent low-temperature thermal decomposition module and connected by a pipeline, and an electric control valve is arranged at the material distribution port; an ash discharge port is arranged at the bottom of the cavity of each module, which is connected to a fly ash storage container through a pipeline, and an electric control valve is arranged at the ash discharge port;

[0012] The intelligent control module includes a human-computer dialogue interface and a main control board, which is connected through cables to: the differential pressure sensor and ash meter installed in the bag dust removal module, the ash meter, temperature sensor and oxygen sensor installed inside the low-temperature thermal decomposition module, as well as the temperature control device of the heater, the speed regulator of the stirring mechanism, and the electric control valves installed at the ash outlet, material distribution outlet and ash discharge outlet.

[0013] As a preferred embodiment of the present invention, 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 pressure difference sensors are arranged on both sides of the partition; a backflush pipe is built into each bag, and each backflush pipe is connected to an air inlet pipe provided with a pulse valve; the lower part of the cavity is an ash hopper in the shape of an inverted cone, a spiral ash guide plate is arranged on its inner wall, an ash meter is arranged on the upper edge of the ash hopper, and an ash outlet is located at the bottom of the ash hopper.

[0014] As a preferred embodiment of the present invention, each bag dust removal module is provided with a parallel pipeline for introducing flue gas, and matching valves are provided on the parallel pipeline and the pipeline connecting adjacent modules; by switching the valve, the flue gas can pass through a short-circuited module to keep the system running continuously.

[0015] As a preferred embodiment of the present invention, the nitrogen inlet of the low-temperature thermal decomposition module is connected to the nitrogen source through a pipeline, a flow meter is provided on the pipeline, and the flow meter is connected to the main control board through a cable; there are multiple temperature sensors, which are respectively 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 meter is arranged on the inner wall of the cavity below the exhaust gas discharge port.

[0016] As a preferred embodiment of the present invention, a conical ash guide plate is provided in the cavity of the low-temperature thermal decomposition module, or at least two inclined ash guide plates are provided in the cavity to form an enclosed area with a larger upper end and a smaller lower end, and the stirring mechanism is located in the center of the enclosed area; the stirring mechanism is a double-axis spiral stirring structure, and the cross-section of the paddles of the stirring structure gradually increases from bottom to top, and a distance is maintained between the paddles and the ash guide plates; the blades on the two rotating shafts rotate in opposite ways, so that the stirred fly ash can move upward.

[0017] As a preferred embodiment of the present invention, the tail gas discharge ports at the top of each low-temperature thermal decomposition module are respectively connected to a discharge pipe through pipelines, and the discharge pipe is connected to a filter, an induced draft fan and a furnace air inlet in sequence.

[0018] As a preferred embodiment of the present invention, each low-temperature thermal decomposition module is arranged in sequence with the position of the bag dust removal module, and is arranged in a step-by-step descending manner; the ash inlet of the rear-stage module is lower than the ash outlet of the previous-stage module, and the connecting pipe between the two is arranged obliquely, forming an angle with the horizontal direction.

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

[0020] (1) When it is put into use for the first time, if the pressure difference in the bag filter module reaches the set value, nitrogen is introduced into the low-temperature thermal decomposition module, and the heater and the induced draft fan are started; when the pressure difference in the bag filter module further increases to the preset value, the electric control valve of the ash outlet is opened according to the set time, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module; after closing the electric control valve, the stirring structure is started to control the reaction temperature of the low-temperature thermal decomposition process to 300-400°C;

[0021] (2) Since fly ash in the flue gas will continue to accumulate in the bag filter module during the production process, it is necessary to open the electric control valve according to the detection signal of the ash meter to discharge the fly ash; if the ash meter signal in the low-temperature thermal decomposition module is detected, the electric control valve of the equalizing port of the current low-temperature thermal decomposition module and the next-level low-temperature thermal decomposition module is opened to allow excess fly ash to enter the next-level low-temperature thermal decomposition module from the connecting pipe; the ash control and discharge operation of the bag filter modules at each level, as well as the ash control and residual material release method in the low-temperature thermal decomposition module, are all executed accordingly;

[0022] (3) During the low-temperature thermal decomposition process, nitrogen input is continuously maintained, and the exhaust gas generated is sent back to the furnace by the induced draft fan after filtering, and the harmful components generated during the thermal decomposition process are eliminated through combustion; after the fly ash continues to stay for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash discharge port is opened to discharge the treated fly ash into the fly ash storage container.

[0023] As a preferred embodiment of the present invention, the amount of fly ash in each level of low-temperature thermal decomposition module is controlled to have a gradient downward trend, and the amount of fly ash in the module of the latter level is less than that in the module of the former level.

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

[0025] Description of the invention principle:

[0026] The inventors noted in their research that the existing pollutant control technology for waste incineration power plants can only transfer gas phase dioxins to the solid phase, and cannot achieve near-zero dioxin emissions. The subsequent disposal of solid phase dioxins is done by downstream companies, which poses serious environmental risks. Although low-temperature thermal decomposition technology can be applied to fly ash dioxin removal and achieve near-zero solid phase dioxin emissions, 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 proposed an intelligent integrated coordinated treatment system for fly ash and dioxins, modified the ash hopper of the dust collector to achieve one-step removal of dust and solid-phase dioxins, ensured the non-oxidizing nature of the flue gas and the temperature stability of the thermal decomposition system through a nitrogen source and an intelligent control module, arranged low-temperature thermal decomposition modules through height differences and set up transportation pipelines to ensure the on-demand transfer of fly ash, set a gradient capacity treatment balance system operating power according to the fly ash temperature gradient, and simultaneously utilized the original waste heat of the fly ash to achieve in-situ efficient low-temperature thermal decomposition and degradation of dioxins from fly ash, and burned the residual components through secondary combustion in a waste incinerator to achieve near-zero emissions of solid-phase dioxins.

[0028] (1) High-efficiency low-temperature thermal decomposition of dioxins:

[0029] Dioxins in fly ash are mainly adsorbed in the activated carbon particles contained therein. When the fly ash is heated, the dioxins in the fly ash undergo complex chemical reactions such as physical desorption, oxidative degradation and resynthesis. In the process of degrading dioxins in fly ash by low-temperature thermal decomposition, -OH continuously replaces Cl in dioxin molecules, and dioxin molecules are oxidized to generate CO 2 , accompanied by the breaking of C-Cl bonds and the formation of a small amount of COC structure. The CaO contained in the fly ash itself is the 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 the chlorine element eventually forms mainly inorganic chloride salts. At the same time, by controlling the non-oxidizing atmosphere, the resynthesis process of dioxins is suppressed.

[0030] Since it is difficult for large-scale devices to stir the fly ash significantly, the carrier gas cannot fully carry away the polluted gas. The present invention adopts a vertically arranged double-axis spiral stirring mechanism, which can fully drive the fly ash in the device to move in an upward trend. Combined with the falling trend of the fly ash itself, the stirring is greatly enhanced, so that the polluted gas can be taken away in time, promoting low-temperature thermal decomposition reactions. At the same time, the design of the ash guide plate makes the space above the module large and the space below small. Combined with the upward movement trend of the fly ash, the uniformity of the fly ash distribution is improved and the internal temperature field is optimized. Furthermore, the fly ash disposed in situ has fine particles and strong reaction activity, which is conducive to the decomposition of dioxins.

[0031] (2) Improving multiple efficiencies through gradient processing

[0032] The present invention innovatively proposes to arrange multiple bag dust removal modules and their respective matching low-temperature thermal decomposition modules in series to achieve gradient treatment of flue gas and fly ash at the same time; this design scheme is mainly based on the following two technical purposes:

[0033] First, multiple bag-type dust removal modules are arranged in series to improve the fly ash interception efficiency and gas passage efficiency. When the fly ash in the flue gas passes through multiple bag-type dust removal modules continuously, it can pass through the previous bag-type dust removal module in an overflow manner without being unable to filter for a short period of time, causing the pressure to rise too quickly. And the less fly ash is contained in the flue gas, the higher the separation efficiency is, which can improve the fly ash interception efficiency and gas passage efficiency as a whole. If multiple bag-type dust removal modules are simply arranged in parallel in the flue, serious bag blockage will occur in each bag-type dust removal module after long-term operation, affecting the overall dust removal effect and ventilation efficiency.

[0034] Secondly, in the multiple bag-type dust removal modules arranged in series, the amount of fly ash adsorbed and settled varies according to the order of the bag-type dust removal modules. That is, the more fly ash the front low-temperature thermal decomposition module receives, and the less the back low-temperature thermal decomposition module receives. Based on this fact, the present invention proposes an original design, which connects the low-temperature thermal decomposition modules in series in sequence to form a continuous gradient disposal process. In the front low-temperature thermal decomposition module, due to the large amount of fly ash received, the fly ash exceeding the set acceptance amount will be continuously discharged to the low-temperature thermal decomposition module of the next level through the transportation pipeline during the production process, and so on. By controlling the ash discharge speed at the bottom of each low-temperature thermal decomposition module, the fly ash of the overloaded module can flow to the next-level module for disposal; by controlling the capacity ratio 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 decomposition efficiency of dioxins in fly ash.

[0035] (3) Intelligent control:

[0036] The intelligent control module automatically adjusts the electric control valve of the ash outlet of the bag-type dust removal module to realize the batch disposal of fly ash, which reduces energy consumption while preventing overload of the bag-type dust removal module and the low-temperature thermal decomposition module; it improves the overall disposal efficiency and ensures the safety of operation and the continuity of equipment operation.

[0037] The intelligent control module automatically controls the electronic control valves of the material equalization ports of each level of low-temperature thermal decomposition module to achieve quantitative gradient treatment of fly ash and optimize the overall economy and operational reliability of the device.

[0038] The intelligent control module automatically controls the temperature field of the low-temperature thermal decomposition module, and realizes full-range temperature control of the fly ash through PID adaptive adjustment of the heater temperature, the speed of the dual-axis spiral stirring mechanism and the nitrogen flow rate, preventing agglomeration due to excessively high temperatures while avoiding the inability to efficiently decompose dioxins inside due to excessively low temperatures, thereby improving the disposal efficiency of the low-temperature thermal decomposition device, extending the service life of the device and ensuring the stability of the disposal process.

[0039] The intelligent control module automatically monitors the oxygen concentration in the low-temperature thermal decomposition module to ensure the airtightness and reducing atmosphere inside the device, improve the dioxin decomposition efficiency of the device, and ensure the high efficiency of disposal.

[0040] The intelligent control module automatically adjusts the ash outlet switch of the low-temperature thermal decomposition module to ensure that the fly ash in the low-temperature thermal decomposition module is promptly discharged into the fly ash storage equipment after dioxin decomposition is completed, ensuring continuous operation of the device.

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

[0042] ① Realize in-situ disposal of solid-phase dioxins. In conventional treatment schemes, fly ash is directly transported out of the factory, which poses environmental risks and increases the total cost of disposal. There is a risk of dioxin escape in the transportation and subsequent disposal links. Since the ash outlet temperature of the dust collector is about 150-180°C, the conventional method of transporting fly ash will reduce the fly ash to room temperature and then heat it for utilization, which will cause a large loss of fly ash waste heat. The present invention innovatively proposes to assemble the low-temperature thermal decomposition module directly below the ash outlet of each bag filter module, so that all fly ash waste heat can be recovered. The spiral ash guide plate prevents the wall fly ash from sticking, reduces the risk of agglomeration, and avoids energy consumption and environmental risks during storage and transportation. The decomposed exhaust gas is directly sent into the furnace using an inert carrier gas. By using the existing incineration conditions and exhaust gas treatment equipment, the secondary pollution problem of dioxins in the thermal desorption exhaust gas is completely avoided, and the equipment expenditure of the secondary combustion chamber and the activated carbon adsorption device is reduced, which has obvious environmental and economic advantages.

[0043] ② The device is highly airtight. The internal structure of a large-scale thermal decomposition device is complex, and it is very easy to produce air leakage points, which reduces the efficiency of dioxin decomposition. The present invention adopts a low-temperature thermal decomposition module. When the module is working, the upper and lower inlets are closed, and the internal connection structure is small, and the air leakage is small. Through high-precision seals and intelligent control modules, it is ensured that the device remains highly airtight during operation, and the internal dioxins can be effectively decomposed. At the same time, the modular design allows regular inspection of single modules and replacement of sealing parts, enhancing the stability of the long-term operation of the device.

[0044] ③Prevent agglomeration. When performing low-temperature thermal decomposition, fly ash has agglomeration problems. The generation of agglomeration prevents the enclosed particles from fully contacting the carrier gas, seriously reducing the thermal decomposition efficiency and possibly causing blockage problems. After dust removal, the fly ash collection module directly collects fly ash for low-temperature thermal decomposition, which can minimize the water absorption of fly ash, keep it in a fine particle state, and improve the reaction activity. Furthermore, large-scale low-temperature thermal decomposition devices usually use inter-wall heating. To ensure that the temperature inside the device meets the requirements, the temperature of the outer wall of the device is often much higher than the temperature inside the device during operation, resulting in the near-wall fly ash temperature being too high (>580°C) and easy to agglomerate. Conventional large-scale thermal decomposition devices have a large amount of fly ash to be disposed of at one time. The size of the low-temperature thermal decomposition device using in-situ modular design is only 1 / 10 of that of conventional devices, and the single disposal volume is small. It can realize group disposal of fly ash, and each module is independently controlled. Through the intelligent control system, multi-module synchronous operation can be achieved, and temperature conditions can be accurately controlled. Finally, the small modular device can continuously stir all fly ash through a double-axis spiral stirring device, and the ash guide plate design realizes temperature field homogenization, further avoiding the occurrence of agglomeration problems.

[0045] ④ Energy saving and carbon reduction. In the bag dust removal module, the temperature of the fly ash shows a gradient downward trend along the airflow direction. Due to the difference in the temperature of the fly ash falling into the low-temperature thermal decomposition modules at each level, a fly ash gradient graded low-temperature thermal decomposition system is set with the capacity ratio of the gradient reduction as the critical value. For example, fly ash is transported to each level of low-temperature thermal decomposition modules at a mass gradient of 5% through a transportation pipeline to balance the operating power of each level of low-temperature thermal decomposition modules, optimize the energy distribution in the system, extend the service life of the equipment, and realize efficient disposal of fly ash on demand.

[0046] ⑤ Realize personalized installation. Conventional thermal decomposition devices are all integrated structures with high installation and modification costs, and adopt a unified disposal process for fly ash from different power plants, which makes it 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. It can be customized and used according to the fly ash bonding characteristics of different power plants and the cleaning pressure difference of the bag, which greatly improves the adaptability and economy of the device. At the same time, the various modules of the device can be freely combined and adjusted, which is suitable for fly ash disposal of different scales and meets diverse treatment needs.

[0047] In summary, the new system can achieve near-zero dioxin emissions by thermally decomposing solid dioxins in fly ash at low temperature in situ at the waste incineration power plant. The present invention can continuously heat fly ash at 300-400°C to control the dioxin content within 20ng·TEQ / kg, and the removal rate reaches more than 95%. Compared with handing over solid dioxins to downstream enterprises for disposal after leaving the factory, it saves the consumption of transportation links, reduces energy, equipment and land costs, has high dioxin disposal efficiency, is thoroughly decomposed, has no tail gas pollution risk, and greatly reduces environmental risks.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The present invention can achieve in-situ efficient low-temperature thermal decomposition of fly ash dioxins, achieve rapid detoxification of fly ash, reduce process energy consumption and environmental risks, and achieve near-zero emissions from waste incineration power plants;

[0050] (2) The present invention can achieve gradient treatment of flue gas and fly ash simultaneously by arranging the bag dust removal module and the matching low-temperature thermal decomposition module in series. The former improves the fly ash interception efficiency and gas passage efficiency as a whole, and the latter can coordinate the fly ash decomposition amount in each module with the temperature in the module by controlling the fly ash capacity ratio in different low-temperature thermal decomposition modules, avoiding power overload of the front module and excess of the rear module, and realizing efficient treatment of fly ash on demand.

[0051] (3) The present invention can achieve effective regulation of the low-temperature thermal decomposition temperature field and the reducing atmosphere through intelligent control, thereby ensuring the disposal efficiency of the device, avoiding fly ash agglomeration, and improving the safety of the device and the efficiency of fly ash resource utilization;

[0052] (4) The present invention modularizes the system and coordinates the design or transformation with the bag dust removal system to improve the airtightness of the device, reduce the system footprint, and achieve cost reduction and efficiency improvement through structural updates;

[0053] (5) The present invention eliminates the design of the ash storage chamber and transportation equipment in the traditional device, reduces the equipment installation, operation and transportation costs, improves the utilization efficiency of the fly ash in-situ thermal energy and kinetic energy, saves energy, and reduces carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a system schematic diagram of the present invention.

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

[0056] Figure 3 Schematic diagram of the structure of the low-temperature thermal decomposition module.

[0057] Figure 4 The low-temperature thermal decomposition modules are arranged in a step-by-step descending manner.

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

[0059] The accompanying drawings are marked with the following symbols: bag dust removal module 1; low-temperature thermal decomposition module 2; intelligent control module 3; fly ash storage container 4; filter 5; induced draft fan 6; furnace 7; flue 8; nitrogen source 9; pulse valve 11; air inlet 12; air outlet 13; differential pressure sensor 14; ash hopper 15; spiral ash guide plate 16; ash outlet 17; ash inlet 21; nitrogen inlet 22; double-axis spiral stirring mechanism 23; exhaust gas discharge port 24; ash meter 25; heater 26; temperature sensor 27; ash guide plate 28; oxygen sensor 29; ash discharge port 30; ash equalizing pipe 31; ash guide plate 32; human-computer dialogue interface 33; main control board 34. DETAILED DESCRIPTION

[0060] First of all, it should be noted that the present invention relates to the field of solid waste incineration pollutant disposal, and is an intelligent integrated disposal system for in-situ rapid detoxification of fly ash dioxins in waste incineration plants. In the implementation process of the present invention, dust removal, ash removal, heat exchange and fly ash storage and other processes will be involved, and the production equipment involved is not limited to: bag filter, automatic valve and pulse injection equipment, etc. The above related processes belong to the prior art, and those skilled in the art can operate the corresponding equipment skillfully. All those mentioned in the application documents of the present invention belong to this category, and the applicant will not list them one by one.

[0061] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. The dioxin content of fly ash before and after treatment in each embodiment is shown in Table 1. Obviously, the embodiment is only the most basic embodiment of the present invention, not all embodiments. Other embodiments based on the present invention belong to the scope of protection of the present invention.

[0062] like Figure 1 As shown, the in-situ rapid detoxification intelligent integrated disposal system for fly ash dioxins in a waste incineration plant provided by the present invention comprises a bag dust removal module 1 arranged on a flue 8, and a matching low-temperature thermal decomposition module 2, an intelligent control module 3 and a fly ash storage container 4. Among them, there are multiple bag dust removal modules 1 and they are arranged in series in sequence. The furnace 7 is connected to the air inlet 12 of the first bag dust removal module 1 through the flue 8. Adjacent bag dust removal modules 1 are connected by pipelines to realize continuous air intake. The air outlet 13 at the top of each bag dust removal module 1 is connected to the tail gas treatment unit.

[0063] like Figure 2As shown, the bag dust removal module 1 has a hollow cavity, which is divided into two parts by the top partition; multiple vertical hollow bags are installed on the partition with their open ends, and differential pressure sensors are arranged on both sides of the partition; a backflush pipe is built into each bag, and each backflush pipe is gathered to the air inlet pipe provided with a pulse valve; the lower part of the cavity is an inverted cone-shaped ash hopper 15, on the inner wall of which a spiral ash guide plate 16 is provided, and the fly ash moves rapidly spirally downward along it relying on its own gravity and pulse backflush force. The ash meter is arranged on the upper edge of the ash hopper, and the ash outlet 17 is located at the bottom of the ash hopper 15. A low-temperature thermal decomposition module 2 is arranged at the bottom of each bag dust removal module 1, and docking is achieved through their respective ash outlets 17 and ash inlet 21, and an electric control valve is arranged at the ash outlet 17. Each bag dust removal module 1 is provided with a parallel pipeline for introducing flue gas, and matching valves are arranged on the parallel pipeline and the pipeline connecting the adjacent modules; by switching the valve, the flue gas can pass through a short-circuited module to keep the system running continuously.

[0064] like Figure 3 As shown, the low-temperature thermal decomposition module 2 is arranged vertically with a hollow inner cavity, a stirring mechanism is arranged inside, and a heater 26 is arranged outside; a nitrogen inlet 22 is arranged in the lower middle part of the cavity, and an exhaust gas discharge port 24 is arranged at the top; the sides of adjacent low-temperature thermal decomposition modules 2 are each provided with a material distribution port and connected by an ash distribution pipe 31, and an electric control valve is arranged at the material distribution port; an ash guide plate 32 is arranged in the ash distribution pipe 31, and its upper surface is parallel to the direction of the pipeline. An ash discharge port 30 is arranged at the bottom of the cavity of each low-temperature thermal decomposition module 2, which is connected to the fly ash storage container 4 through a pipeline, and an electric control valve is arranged at the ash discharge port 30. The nitrogen inlet 22 of the low-temperature thermal decomposition module 2 is connected to the nitrogen source 9 (such as a nitrogen tank or an air separation device) through a pipeline, and a flow meter is arranged on the pipeline, and the flow meter is connected to the main control board 34 in the intelligent control module 3 through a cable. A conical ash guide plate 28 is provided in the cavity of the low-temperature thermal decomposition module 2, or at least two inclined ash guide plates 28 are provided in the cavity to form an enclosed area with a larger upper end and a smaller 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 respectively connected to the discharge pipe through pipelines, and the discharge pipe is connected to the filter 5, the induced draft fan 6 and the air inlet of the furnace 7 in sequence.

[0065] As an optional solution, 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 baffle in the bag filter. The stirring mechanism is a double-axis spiral stirring structure 23, the cross-section of its blades gradually increases from bottom to top, the blade angle is the same as the inclination angle of the ash guide plate 28 and the spacing is maintained; the blades on the two rotating shafts rotate in opposite ways, so that the stirred fly ash can move upward and the fly ash is evenly distributed. There are multiple temperature sensors 27, which are respectively arranged on the shaft of the stirring mechanism and on the inner wall of the cavity; the heater 26 is an electric heater, or a flue gas heat exchanger; the electric heater is connected to the power device of the waste incineration plant through a cable, and the flue gas heat exchanger is connected to the flue of the waste incinerator through a pipe. The ash meter 25 is arranged on the inner wall of the cavity below the exhaust gas outlet 24.

[0066] like Figure 4 As shown, each low-temperature thermal decomposition module 2 can be optionally arranged in sequence with the position of the bag dust removal module 1, and arranged in a step-by-step descending manner; the material distribution port of the low-temperature thermal decomposition module 2 at the latter stage is lower than the ash distribution port of the low-temperature thermal decomposition module 2 at the former stage, and the ash distribution pipe 31 between the two is arranged obliquely, forming an angle with the horizontal direction.

[0067] like Figure 5 As shown, the intelligent control module 3 includes a human-computer dialogue interface 33 (such as a liquid crystal display) and a main control board 34, and the main control board 34 is connected through cables to: the differential pressure sensor 14 and the ash meter provided in the bag dust removal module 1, the ash meter 25, the temperature sensor 27 and the oxygen sensor 29 provided inside the low-temperature thermal decomposition module 2, as well as the temperature control device of the heater 28, the speed regulator of the stirring mechanism, and the electric control valves provided at the ash outlet 17, the material distribution outlet and the ash discharge outlet 30.

[0068] The intelligent control module 3 identifies the pressure difference between the air inlet and outlet of the bag dust removal module through the pressure difference sensor 14, and starts the system control strategy according to the preset control scheme. The intelligent control module 3 receives the data from the temperature sensor 27 on the wall of the low-temperature thermal decomposition module 2 and the axis of the double-screw stirring mechanism 23, which is used to calculate the temperature field in the equipment, and then automatically adjusts the working state of the heater 28, the speed of the double-axis spiral stirring mechanism 23 and the nitrogen flow rate through the PID control system, and at the same time controls the minimum and maximum temperatures inside 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 ash meter data from the bag dust removal module 1 and the low-temperature thermal decomposition module 2. The human-machine dialogue interface 33 (such as a liquid crystal display) in the intelligent control module 3 can display the following contents: the pressure difference of the bag dust removal module 1, the oxygen concentration in the low-temperature thermal decomposition module 2, the heating time of the heater 28, the rotation speed of the double-axis spiral stirring mechanism 23, the nitrogen flow rate, and the wall surface and axial temperature of the double-axis spiral stirring mechanism transmitted by each temperature sensor 27. The data transmitted by each sensor is used to perform autonomous calculations according to a predetermined control strategy to realize control decisions on the temperature field and fly ash disposal.

[0069] As common sense that can be understood by those skilled in the art, the main control board of the present invention is essentially a computing device, which includes: a memory, configured to store instructions; and a processor, configured to call the instructions from the memory and to implement the intelligent integrated disposal method for in-situ rapid detoxification of fly ash dioxins in the waste incineration plant in the present invention when executing the instructions. At the same time, the main control board also includes a computer-readable storage medium, on which instructions are stored, and the instructions are used to enable the computing 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: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0070] Based on the above innovative structure device, the present invention can realize the intelligent integrated treatment method of in-situ rapid detoxification of dioxins in fly ash from waste incineration plants, which specifically includes:

[0071] (1) When the bag filter module 1 is put into use for the first time, if the pressure difference inside the bag filter module 1 reaches the set value, nitrogen is introduced into the low-temperature thermal decomposition module 2, and the heater 28 and the induced draft fan 6 are started; when the pressure difference inside 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, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module 2; after closing the electric control valve, the stirring structure is started to control the reaction temperature of the low-temperature thermal decomposition process to 300-400°C;

[0072] (2) Since fly ash in the flue gas will continue to accumulate in the bag filter module 1 during the production process, it is necessary to open the electric control valve according to the detection signal of the ash meter to perform the fly ash discharge operation; if the signal of the ash meter 25 in the low-temperature thermal decomposition module 2 is detected, the electric control valve of the equalizing port of the current low-temperature thermal decomposition module 2 and the next-level low-temperature thermal decomposition module 2 is opened to allow excess fly ash to enter the next-level low-temperature thermal decomposition module 2 from the ash equalizing pipe 31; the ash control and discharge operation of each level of bag filter module 1, as well as the ash control and residual material release method in the low-temperature thermal decomposition module 2, are all executed accordingly;

[0073] (4) During the low-temperature thermal decomposition process, nitrogen input is continuously maintained, and the exhaust gas generated is sent back to the furnace 7 by the induced draft fan 6 after being filtered, and the harmful components generated during the thermal decomposition process are eliminated through combustion; after the fly ash continues to stay for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash discharge port 30 is opened to discharge the treated fly ash into the fly ash storage container 4.

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

[0075] Example 1

[0076] As an example solution, the heater is selected to be an electric heat exchanger.

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

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

[0079] (2) Through automatic control by the intelligent control module, when the pressure difference sensor shows that the pressure difference in the bag filter module reaches 1600Pa, the dioxin in-situ rapid detoxification intelligent integrated disposal system is started, the ash outlet of the fly ash collection module is opened, and the fly ash falls into the low-temperature thermal decomposition module. After 2 minutes, the ash outlet of the fly ash collection module and the ash inlet of the low-temperature thermal decomposition device are closed;

[0080] (3) Automatically control by the intelligent control module: when the ash meter 1 shows that the amount of fly ash in the primary low-temperature thermal decomposition module reaches 85%, the uniform ash outlet 1 and the uniform ash inlet 2 are opened; when the ash meter 1 shows that the amount of fly ash is 80%, the uniform ash outlet 1 is closed, and the uniform ash inlet 2 is closed after 10 seconds; when the ash meter 2 shows that the amount of fly ash in the secondary low-temperature thermal decomposition module reaches 80%, the uniform ash outlet 2 and the uniform ash inlet 3 are opened; when the ash meter 2 shows that the amount of fly ash is 75%, the uniform ash outlet 2 is closed, and the uniform ash inlet 3 is closed after 10 seconds; when the ash meter 3 shows that the amount of fly ash in the tertiary low-temperature thermal decomposition module reaches 75%, the uniform ash outlet 3 and the uniform ash inlet 4 are opened; when the ash meter 3 shows that the amount of fly ash is 70%, the uniform ash outlet 3 is closed, and the uniform ash inlet 4 is closed after 10 seconds, so as to ensure that the amount of fly ash disposed in the sequentially arranged low-temperature thermal decomposition modules is uniform;

[0081] (4) Through automatic control by the intelligent control module, when the fly ash begins to fall into the low-temperature decomposition module, the double-helix stirring mechanism is started, and the main control board controls the stirring speed to 3r / min and the nitrogen flow rate to 1L / min for 30 minutes. The average temperature feedback from the temperature sensor is used as the feedback point, and 350°C is used as the reference value. The heater temperature, the stirring speed of the double-helix stirring mechanism, and the nitrogen flow rate are regulated by the PID control system to ensure that the temperature field of the fly ash can be stabilized between 300 and 400°C, 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 rate: 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, and the ash outlet of the low-temperature thermal decomposition module is opened to allow the fly ash to enter the fly ash collection and storage equipment through the ash outlet to obtain dioxin detoxification fly ash with a dioxin toxicity equivalent of 8.7 ng-TEQ / kg.

[0088] Example 2

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

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

[0091] (1) Through automatic control by the intelligent control module, when the display screen shows that the pressure difference in the bag filter module reaches 1500Pa, the air inlet of the low-temperature thermal decomposition module is opened, the nitrogen source, heater and induced draft fan are started, and the main control board controls the nitrogen flow rate to 1L / min, the oxygen concentration to 0.3%, and the average temperature in the low-temperature thermal decomposition module to 400°C;

[0092] (2) Through automatic control by the intelligent control module, when the pressure difference sensor shows that the pressure difference in the bag filter module reaches 1800Pa, the dioxin in-situ rapid detoxification intelligent integrated disposal system is started, the ash outlet of the fly ash collection module is opened, and the fly ash falls into the low-temperature thermal decomposition module. After 5 minutes, the ash outlet of the fly ash collection module and the ash inlet of the low-temperature thermal decomposition device are closed;

[0093] (3) Automatically control by the intelligent control module: when the ash meter 1 shows that the amount of fly ash in the primary low-temperature thermal decomposition module reaches 85%, the uniform ash outlet 1 and the uniform ash inlet 2 are opened; when the ash meter 1 shows that the amount of fly ash is 80%, the uniform ash outlet 1 is closed, and the uniform ash inlet 2 is closed after 10 seconds; when the ash meter 2 shows that the amount of fly ash in the secondary low-temperature thermal decomposition module reaches 80%, the uniform ash outlet 2 and the uniform ash inlet 3 are opened; when the ash meter 2 shows that the amount of fly ash is 75%, the uniform ash outlet 2 is closed, and the uniform ash inlet 3 is closed after 10 seconds; when the ash meter 3 shows that the amount of fly ash in the tertiary low-temperature thermal decomposition module reaches 75%, the uniform ash outlet 3 and the uniform ash inlet 4 are opened; when the ash meter 3 shows that the amount of fly ash is 70%, the uniform ash outlet 3 is closed, and the uniform ash inlet 4 is closed after 10 seconds, so as to ensure that the amount of fly ash disposed in the sequentially arranged low-temperature thermal decomposition modules is uniform;

[0094] (4) Through automatic control by the intelligent control module, when the fly ash begins to fall into the low-temperature decomposition module, the double-helix stirring mechanism is started, and the main control board controls the stirring speed to 20r / min and the nitrogen flow rate to 5L / min for 1 hour. The average temperature feedback from the temperature sensor is used as the feedback point, and 350°C is used as the reference value. The heater temperature, the stirring speed of the double-helix stirring mechanism, and the nitrogen flow rate are regulated by the PID control system to ensure that the temperature field of the fly ash can be stabilized between 300 and 400°C, 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, and the ash outlet of the low-temperature thermal decomposition module is opened to allow the fly ash to enter the fly ash collection and storage equipment through the ash outlet to obtain dioxin detoxification fly ash with a dioxin toxicity equivalent of 8.7 ng-TEQ / kg.

[0101] Example 3

[0102] As an example solution, the heater is selected to be an electric heat exchanger.

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

[0104] (1) Through automatic control by the intelligent control module, when the display screen shows that the pressure difference in the bag filter module reaches 1500Pa, the air inlet of the low-temperature thermal decomposition module is opened, the nitrogen source, heater and induced draft fan are started, and the main control board controls the nitrogen flow rate to 1L / min, the oxygen concentration to 0.2%, and the average temperature in the low-temperature thermal decomposition module to 300°C;

[0105] (2) Through automatic control by the intelligent control module, when the pressure difference sensor shows that the pressure difference in the bag filter module reaches 1700Pa, the dioxin in-situ rapid detoxification intelligent integrated disposal system is started, the ash outlet of the fly ash collection module is opened, and the fly ash falls into the low-temperature thermal decomposition module. After 3 minutes, the ash outlet of the fly ash collection module and the ash inlet of the low-temperature thermal decomposition device are closed;

[0106] (3) Automatically control by the intelligent control module: when the ash meter 1 shows that the amount of fly ash in the primary low-temperature thermal decomposition module reaches 85%, the uniform ash outlet 1 and the uniform ash inlet 2 are opened; when the ash meter 1 shows that the amount of fly ash is 80%, the uniform ash outlet 1 is closed, and the uniform ash inlet 2 is closed after 10 seconds; when the ash meter 2 shows that the amount of fly ash in the secondary low-temperature thermal decomposition module reaches 80%, the uniform ash outlet 2 and the uniform ash inlet 3 are opened; when the ash meter 2 shows that the amount of fly ash is 75%, the uniform ash outlet 2 is closed, and the uniform ash inlet 3 is closed after 10 seconds; when the ash meter 3 shows that the amount of fly ash in the tertiary low-temperature thermal decomposition module reaches 75%, the uniform ash outlet 3 and the uniform ash inlet 4 are opened; when the ash meter 3 shows that the amount of fly ash is 70%, the uniform ash outlet 3 is closed, and the uniform ash inlet 4 is closed after 10 seconds, so as to ensure that the amount of fly ash disposed in the sequentially arranged low-temperature thermal decomposition modules is uniform;

[0107] (4) Through automatic control by the intelligent control module, when the fly ash begins to fall into the low-temperature decomposition module, the double-helix stirring mechanism is started, and the main control board controls the stirring speed to 10r / min and the nitrogen flow rate to 3L / min for 45min. The average temperature feedback from the temperature sensor is used as the feedback point, and 350°C is used as the reference value. The heater temperature, the stirring speed of the double-helix stirring mechanism, and the nitrogen flow rate are regulated by the PID control system to ensure that the temperature field of the fly ash can be stabilized between 300 and 400°C, 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 rate: 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 dioxin in-situ rapid detoxification intelligent integrated disposal system is stopped, and the ash outlet of the low-temperature thermal decomposition module is opened to allow the fly ash to enter the fly ash collection and storage equipment through the ash outlet to obtain dioxin detoxification fly ash with a dioxin toxicity equivalent of 9.3 ng-TEQ / kg.

[0114] Table 1 Dioxin content in fly ash before and after treatment

[0115] project Example 1 Example 2 Example 3 Before treatment / (ngTEQ / kg) 553 604 378 After treatment / (ngTEQ / kg) 8.7 10.6 9.3 Removal rate / % 98.4 98.3 97.2

[0116] The above are specific embodiments of the present invention. Obviously, those skilled in the art can make various subsequent applications, supplements, modifications and variations to the present invention without departing from the spirit and scope of the present invention. If various applications, supplements, modifications and variations based on the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include such applications, supplements, modifications and variations.

Claims

1. An intelligent integrated treatment system for rapid in-situ detoxification of fly ash dioxins from waste incineration plants, characterized in that: It includes a bag dust removal module installed on the flue, as well as a matching low-temperature thermal decomposition module, a fly ash storage container and an intelligent control module; among which, There are multiple bag dust removal modules which are arranged in series. The furnace is connected to the air inlet of the first module through the flue. Adjacent modules are connected by pipelines to achieve continuous air intake. The air outlet on the top of each module is connected to the tail gas treatment unit. A low-temperature thermal decomposition module is set at the bottom of each bag dust removal module, and they are connected through their respective ash outlets and ash inlets. An electric control valve is set at the ash outlet. The low-temperature thermal decomposition module has a hollow inner cavity, a stirring mechanism is arranged inside, and a heater is arranged outside; a nitrogen inlet is arranged at the lower middle part of the cavity, and an exhaust gas discharge port is arranged at the top; a material distribution port is arranged at the side of each adjacent low-temperature thermal decomposition module and connected by a pipeline, and an electric control valve is arranged at the material distribution port; an ash discharge port is arranged at the bottom of the cavity of each module, which is connected to a fly ash storage container through a pipeline, and an electric control valve is arranged at the ash discharge port; The intelligent control module includes a human-computer dialogue interface and a main control board, which is connected through cables to: the differential pressure sensor and ash meter installed in the bag dust removal module, the ash meter, temperature sensor and oxygen sensor installed inside the low-temperature thermal decomposition module, as well as the temperature control device of the heater, the speed regulator of the stirring mechanism, and the electric control valves installed at the ash outlet, material distribution outlet and ash discharge outlet.

2. The system according to claim 1, characterized in that 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 pressure difference sensors are arranged on both sides of the partition; a backflush pipe is built into each bag, and each backflush pipe is connected to an air inlet pipe provided with a pulse valve; the lower part of the cavity is an inverted cone-shaped ash hopper, a spiral ash guide plate is arranged on its inner wall, an ash meter is arranged on the upper edge of the ash hopper, and an ash outlet is located at the bottom of the ash hopper.

3. The system according to claim 1, characterized in that Each bag dust removal module is equipped with a parallel pipeline for introducing flue gas, and matching valves are provided on the parallel pipeline and the pipeline connecting the adjacent modules; by switching the valve, the flue gas can pass through a short-circuited module to keep the system running continuously.

4. The system according to claim 1, characterized in that The nitrogen inlet of the low-temperature thermal decomposition module is connected to the nitrogen source through a pipeline, and a flow meter is provided on the pipeline, and the flow meter is connected to the main control board through a cable; there are multiple temperature sensors, which are respectively 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 meter is arranged on the inner wall of the cavity below the exhaust gas discharge port.

5. The system according to claim 1, characterized in that A conical ash guide plate is provided in the cavity of the low-temperature thermal decomposition module, or at least two inclined ash guide plates are provided in the cavity to form an enclosed area with a larger upper end and a smaller lower end, and the stirring mechanism is located in the center of the enclosed area; the stirring mechanism is a double-axis spiral stirring structure, and the cross-section of the paddles of the stirring structure gradually increases from bottom to top, and a distance is maintained between the paddles and the ash guide plate; the blades on the two rotating shafts rotate in opposite ways, so that the stirred fly ash can move upward.

6. The system according to claim 1, characterized in that The tail gas discharge ports at the top of each low-temperature thermal decomposition module are respectively collected to the discharge pipe through pipelines, and the discharge pipe is connected to the filter, the induced draft fan and the furnace air inlet in sequence.

7. The system according to claim 1, characterized in that The low-temperature thermal decomposition modules are arranged in sequence with the position of the bag dust removal module, and are arranged in a step-by-step descending manner; the ash inlet of the rear module is lower than the ash outlet of the previous module, and the connecting pipe between the two is arranged obliquely, forming an angle with the horizontal direction.

8. A method for realizing an intelligent integrated treatment method for in-situ rapid detoxification of dioxins from fly ash in a waste incineration plant using the system described in claim 1, characterized in that: include: (1) When it is put into use for the first time, if the pressure difference in the bag filter module reaches the set value, nitrogen is introduced into the low-temperature thermal decomposition module, and the heater and the induced draft fan are started; when the pressure difference in the bag filter module further increases to the preset value, the electric control valve of the ash outlet is opened according to the set time, so that the fly ash falls into the inner cavity of the low-temperature thermal decomposition module; after closing the electric control valve, the stirring structure is started to control the reaction temperature of the low-temperature thermal decomposition process to 300-400°C; (2) Since fly ash in the flue gas will continue to accumulate in the bag filter module during the production process, it is necessary to open the electric control valve according to the detection signal of the ash meter to discharge the fly ash; if the ash meter signal in the low-temperature thermal decomposition module is detected, the electric control valve of the equalizing port of the current low-temperature thermal decomposition module and the next-level low-temperature thermal decomposition module is opened to allow excess fly ash to enter the next-level low-temperature thermal decomposition module from the connecting pipe; the ash control and discharge operation of the bag filter modules at each level, as well as the ash control and residual material release method in the low-temperature thermal decomposition module, are all executed accordingly; (3) During the low-temperature thermal decomposition process, nitrogen input is continuously maintained, and the exhaust gas generated is sent back to the furnace by the induced draft fan after filtering, and the harmful components generated during the thermal decomposition process are eliminated through combustion; after the fly ash continues to stay for a sufficient time to complete the low-temperature thermal decomposition, the electric control valve of the ash discharge port is opened to discharge the treated fly ash into the fly ash storage container.

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

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

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