A device for water thermal detoxification of household garbage incineration fly ash

Abstract

This invention discloses a hydrothermal detoxification device for fly ash from municipal solid waste incineration, comprising a reactor, a pulse jet suspension mechanism, a differential speed agitation mechanism, and a static hydraulic cavitation mechanism. The pulse jet suspension mechanism is located at the bottom of the reactor to maintain fluidization throughout the reactor. The differential speed agitation mechanism is located in the middle of the reactor to perform high-frequency shearing and surface activation of suspended particles. The static hydraulic cavitation mechanism is located at the top of the reactor to enhance the hydraulic cavitation effect and increase the material reaction rate. The pulse jet suspension mechanism, differential speed agitation mechanism, and static hydraulic cavitation mechanism are all connected to an external control system for independent decoupled control. This invention features a compact structure, ease of use, and high reliability. It can enhance mass transfer and reaction in a highly alkaline environment through a low-speed, high-shear agitation system, significantly improving the effectiveness of hydrothermal detoxification of fly ash.

Description

Technical Field

[0001] This invention relates to the field of municipal solid waste incineration fly ash treatment technology, specifically to a hydrothermal detoxification device for municipal solid waste incineration fly ash. Background Technology

[0002] Heavy metals (such as Pb, Cd, Cr, and Zn) in fly ash from municipal solid waste incineration are easily leached into the natural environment. Dioxins are highly toxic and difficult to degrade, and improper disposal can cause serious harm to soil, groundwater, and human health. Currently, fly ash disposal technologies mainly include solidification / stabilization, co-processing in cement kilns, high-temperature melting, and hydrothermal treatment. Among these, hydrothermal treatment technology has received widespread attention due to its high treatment efficiency, low secondary pollution, and ability to stabilize heavy metals and degrade dioxins under intermediate temperature conditions.

[0003] The basic principle of hydrothermal treatment of fly ash is to use water as a medium in a closed reactor, and generate autogenous pressure through heating (usually between 150℃ and 260℃). This causes the aluminosilicate components in the fly ash to dissolve and recrystallize under alkaline conditions, forming stable mineral phases such as hydrogrossular and seldomite, which encapsulate heavy metals within the crystal structure, thus achieving stabilization. Simultaneously, the hydrothermal conditions can also promote the dechlorination and degradation of dioxins. Studies have shown that fly ash itself possesses a certain degree of alkalinity and aluminosilicate components, allowing for hydrothermal reactions without the addition of external additives. For example, mixing fluidized bed fly ash (rich in aluminosilicate) with grate furnace fly ash (highly alkaline) in a certain proportion can hydrothermally synthesize hydrogrossular and seldomite, significantly reducing the heavy metal leaching rate.

[0004] Currently, hydrothermal reactors used for fly ash treatment mainly draw on the design of general-purpose hydrothermal reactors. Their basic structure includes: (1) Reactor body: usually adopts a double-layer structure, with the inner layer being a corrosion-resistant alloy and the outer layer being a pressure-bearing shell, with a design pressure of 1.6 MPa to 20 MPa and a design temperature of 200℃ to 350℃. (2) Heating system: mostly adopts jacketed electric heating or heat transfer oil heating, and some studies have tried radio frequency heating to improve heating uniformity. (3) Stirring system: conventionally configured as top mechanical stirring or magnetically driven stirring, with stirring forms mostly being anchor type, paddle type or turbine type, and the speed is usually 100 rpm to 500 rpm; some devices use pneumatic magnetic stirrers, which achieve non-contact stirring through magnetic coupling transmission. (4) Control unit: including basic functions such as temperature control, pressure monitoring, and safety pressure relief. However, the above-mentioned general-purpose hydrothermal reactors are mainly for chemical synthesis, material preparation and other fields, and have not been optimized for the special characteristics of highly alkaline fly ash slurry, and have exposed many technical shortcomings in practical applications.

[0005] At the same time, existing hydrothermal reactors have the following drawbacks when treating highly alkaline fly ash: (1) The laboratory scale is disconnected from the engineering scale-up: it only focuses on laboratory verification and does not consider the engineering scale-up problem, and lacks modular and continuous design.

[0006] (2) Insufficient stirring and particle suspension performance: The stirring system is simple and optimized for high-density, high-solids fly ash slurry, so the particles are easy to settle; the material particles have large volume and density, so a high speed is required to maintain particle suspension, resulting in high energy consumption, large frictional heat, easy wear of seals, and reduced air tightness of the reactor.

[0007] (3) Rigid mass transfer and fluid path control: The fixed baffle structure in the reaction device cannot be dynamically adjusted and is difficult to adapt to changes in material properties; the functions of stirring, suspension, and mixing are coupled in the same system and are difficult to optimize independently, resulting in a significant decrease in reaction efficiency after the equipment is scaled up.

[0008] (4) Surface passivation of catalytic oxidant: The reaction process requires the addition of catalytic oxidant. Because the reaction environment is high temperature, high pressure and high alkalinity, the reagent is easily deactivated quickly.

[0009] (5) The fly ash material has high content of alkalinity, chloride ions and calcium aluminum silicon sulfate. Under the high temperature and high speed mixing environment, it causes serious wear and corrosion to the reaction device, and targeted optimization is required. Summary of the Invention

[0010] The technical problem to be solved by this invention is to address the four core challenges of existing hydrothermal reactors in treating highly alkaline fly ash: "high energy consumption, low mass transfer, easy deactivation, and difficulty in scale-up". The invention provides a compact, easy-to-operate hydrothermal detoxification device for municipal solid waste incineration fly ash that can achieve efficient mass transfer, continuous activation, and synergistic enhancement.

[0011] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A hydrothermal detoxification device for fly ash from municipal solid waste incineration includes a reactor, a pulse jet suspension mechanism, a differential speed agitation mechanism, and a static hydraulic cavitation mechanism. The pulse jet suspension mechanism is located at the bottom of the reactor to maintain fluidization throughout the reactor. The differential speed agitation mechanism is located in the middle of the reactor to perform high-frequency shearing and surface activation of suspended particles. The static hydraulic cavitation mechanism is located at the top of the reactor to enhance the hydraulic cavitation effect and increase the material reaction rate. The pulse jet suspension mechanism, differential speed agitation mechanism, and static hydraulic cavitation mechanism are all connected to an external control system for independent decoupled control.

[0012] As a further improvement of the present invention, the pulse jet suspension mechanism includes a high-pressure pulse pump disposed outside the reactor and a multi-layer concentrically arranged jet ring disposed at the bottom of the reactor, wherein multiple jet nozzles are evenly distributed on the jet ring; the high-pressure pulse pump is connected to the jet ring through a first air inlet pipe.

[0013] As a further improvement of the present invention, the multi-layer concentrically arranged jet rings include an upper jet ring, a middle jet ring, and a lower jet ring with successively decreasing diameters. The upper jet ring is close to the bottom of the differential transmission stirring mechanism, and the lower jet ring is close to the discharge port at the bottom of the reactor.

[0014] As a further improvement of the present invention, the jet nozzles are distributed at an angle of 30° to 60° toward the top of the reactor, and the inclination angles of the jet nozzles on the upper jet ring, the middle jet ring and the lower jet ring increase sequentially.

[0015] As a further improvement of the present invention, the differential transmission stirring mechanism includes a main stirring frame, a planetary differential stirring assembly, an inner stirring shaft, and an outer stirring shaft; the inner stirring shaft is nested inside the outer stirring shaft, the outer stirring shaft is connected to the main stirring frame to drive the main stirring frame, and the inner stirring shaft is connected to the planetary differential stirring assembly to drive the planetary differential stirring assembly.

[0016] As a further improvement of the present invention, the rotational speed of the inner stirring shaft is 50-100 rpm, and the rotational speed of the outer stirring shaft is 10-60 rpm.

[0017] As a further improvement of the present invention, the outer side of the planetary differential stirring assembly is provided with a plurality of composite tooth combs along the vertical direction, and the interval between two adjacent composite tooth combs is 5 to 12 mm.

[0018] As a further improvement of the present invention, the composite comb includes a comb body, a plurality of protrusions are evenly distributed around the outer periphery of the comb body, and an elastic connector is provided at the root of the teeth of the comb body, the elastic connector being connected to the blade.

[0019] As a further improvement of the present invention, the static hydraulic cavitation mechanism includes an external circulation pump, a fixed dispersion toothed ring, a venturi tube, and a cavitation disk. The cavitation disk is fixed to the top of the reactor, and the venturi tube is disposed on the cavitation disk. The venturi tube is connected to the external circulation pump disposed outside the reactor through a second air inlet pipe. When the external circulation pump pressurizes and sends fly ash slurry into the venturi tube, microbubbles are formed to achieve partial hydraulic cavitation. The fixed dispersion toothed ring is disposed at the outlet of the cavitation disk to perform secondary shearing and crushing of the slurry containing cavitation bubbles.

[0020] As a further improvement of the present invention, the inner wall of the reactor is provided with guide strips that are spirally distributed and have an adjustable inclination angle, the inclination angle of the guide strips being 15° to 30°.

[0021] Compared with the prior art, the advantages of the present invention are as follows: 1. The hydrothermal detoxification device for fly ash from municipal solid waste incineration of the present invention, through functional decoupling design, independently controls and coordinates the three major functions of particle suspension, micro-shearing, and cavitation enhancement. It achieves a mass transfer effect superior to traditional high-speed stirring under low-speed conditions of ≤100 rpm, significantly reducing energy consumption while maintaining high-efficiency catalyst activity and pollutant degradation capacity. The performance degradation from laboratory to engineering scale is significantly better than that of traditional devices, fundamentally solving the technical problems of "high speed dependence - high energy consumption - easy deactivation - difficult to scale up" in existing technologies.

[0022] 2. The hydrothermal detoxification device for fly ash from municipal solid waste incineration of the present invention features a comb-micro-convex structure that continuously renews the catalyst surface through microscopic collisions, thereby improving the freshness of the surface of the active particles after the reaction; static cavitation and stirring are decoupled, increasing the free radical yield and maintaining high-efficiency reaction activity in a highly alkaline environment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the structural principle of the hydrothermal detoxification device for fly ash from municipal solid waste incineration in a specific embodiment of the present invention. Figure 2 This is a top view schematic diagram of the pulse jet suspension mechanism in a specific embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the structural principle of the composite toothed comb in a specific embodiment of the present invention; Figure 4 This is a schematic diagram of the partial structure of the static hydraulic cavitation mechanism in a specific embodiment of the present invention.

[0024] Legend: 100, Reactor; 101, Guide bar; 200, Pulse jet suspension mechanism; 201, High-pressure pulse pump; 202, First air inlet pipe; 203, Upper jet ring; 204, Middle jet ring; 205, Lower jet ring; 206, Jet nozzle; 207, Connecting rod; 300, Differential transmission stirring mechanism; 301, Main stirring frame; 302, Planetary differential stirring assembly; 303, Composite toothed comb; 3031, Toothed comb body; 3032, Boss; 3033, Elastic connector; 304, Inner stirring shaft; 305, Outer stirring shaft; 306, Impeller; 400, Static hydraulic cavitation mechanism; 401, External circulation pump; 402, Second air inlet pipe; 403, Fixed dispersion toothed ring; 404, Venturi tube; 405, Cavitation disc. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0026] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0028] Example 1 like Figure 1 As shown, the hydrothermal detoxification device for municipal solid waste incineration fly ash of the present invention has a stirring shaft rotation speed controlled within the range of 10-100 rpm. The hydrothermal detoxification device includes a reactor 100, a pulse jet suspension mechanism 200, a differential speed drive stirring mechanism 300, and a static hydraulic cavitation mechanism 400. The pulse jet suspension mechanism 200 is located at the lower part of the reactor 100 to maintain fluidization throughout the reactor. The differential speed drive stirring mechanism 300 is located in the middle of the reactor 100 to perform high-frequency shearing and surface activation of suspended particles. The static hydraulic cavitation mechanism 400 is located at the upper part of the reactor 100 to enhance the hydraulic cavitation effect and increase the material reaction rate. The pulse jet suspension mechanism 200, the differential speed drive stirring mechanism 300, and the static hydraulic cavitation mechanism 400 are all connected to an external control system for independent decoupled control. The external control system serves as the data collection and intelligent analysis system for the hydrothermal detoxification device. Based on real-time monitoring and collection of data such as light transmittance, stirring torque, and material density, it automatically adjusts parameters such as stirring intensity and pulse jet rate, and switches between suspension start-up mode, reaction maintenance mode, and enhanced treatment mode.

[0029] In this embodiment, spirally distributed guide strips 101 are provided on the inner wall of the reactor 100, and the inclination angle of the guide strips 101 can be flexibly adjusted between 15° and 30°. The guide strips 101 cooperate with the differential transmission stirring mechanism 300 to enhance the homogenization effect of the slurry. It is known that a top cover (not shown in the figure) is provided on the top of the reactor 100, and the cover is provided with a feed inlet and a stirring drive motor. The bottom of the reactor 100 can be designed as a double-cone structure, with an upper cone angle of 100° to 130° and a lower cone angle of 50° to 70°.

[0030] In this embodiment, addressing the technical challenges of "high speed dependence, high energy consumption, easy deactivation, and difficulty in scale-up" in the hydrothermal treatment of highly alkaline incinerator fly ash, a functional decoupling design concept is adopted. The three main functions—particle suspension, microscopic shearing, and cavitation enhancement—are separated from the traditional single stirring system and are independently performed by the pulse jet suspension mechanism 200 at the bottom of reactor 1, the differential speed drive stirring mechanism 300 in the middle layer, and the static hydraulic cavitation mechanism 400 at the top layer, respectively. These three layers are functionally completely decoupled and can be independently optimized, while being highly integrated and operating collaboratively in space. This achieves a mass transfer effect superior to traditional high-speed stirring under low-speed conditions where the stirring shaft speed does not exceed a certain threshold, fundamentally solving the core defects of existing technologies.

[0031] like Figure 1 and Figure 2 As shown, the pulse jet suspension mechanism 200 includes a high-pressure pulse pump 201 disposed outside the reactor 100 and a multi-layered concentrically arranged jet ring disposed at the bottom of the reactor 100, with multiple jet nozzles 206 evenly distributed on the jet ring; the high-pressure pulse pump 201 is connected to the jet ring through a first air inlet pipe 202. The jet velocity is 1–15 m / s, and the pulse frequency is adjustable from 1 to 60 Hz, used for flushing and maintaining fluidization of the entire reactor when material sedimentation occurs at the bottom of the reactor 1 or when the pipeline is blocked during the discharge process.

[0032] Furthermore, the multi-layered concentrically arranged jet rings include an upper jet ring 203, a middle jet ring 204, and a lower jet ring 205 with successively decreasing diameters. Adjacent jet rings are connected by a connecting rod 207. The upper jet ring 203 is located near the bottom of the differential drive stirring mechanism 300, and the lower jet rings 205 are located near the discharge port at the bottom of the reactor 100, spaced 50-100 mm apart. This three-dimensional layered structure establishes a gradual energy transfer gradient from the reactor bottom to the stirring zone—the lower jet ring 205 provides initial support, the middle jet ring 204 maintains suspension, and the upper jet ring 203 connects with the stirring flow field, forming a more complete vertical fluidization channel and effectively preventing back-mixing and deposition of high-density particles in the middle height region.

[0033] Furthermore, the jet nozzles 206 are distributed at an angle of 30° to 60° toward the top of the reactor 100, and the inclination angles of the jet nozzles 206 on the upper jet ring 203, middle jet ring 204, and lower jet ring 205 increase sequentially. The airflow ejected from the jet nozzles 206 with larger inclination angles forms a larger upward angle to promote the lifting of particles in the central region, while the airflow ejected from the jet nozzles 206 with smaller inclination angles obliquely scours the reactor wall area at a smaller angle, eliminating suspended dead zones near the wall surface. Multiple spray directions are integrated on the same jet ring, with the jet nozzles 206 spraying in different directions. For example, vertically upward spray holes can lift settled particles, tangential spray holes can form a rotating flow field, and radially inward spray holes can prevent central dead zones.

[0034] In this embodiment, the pulse jet suspension mechanism 200 works as follows: Addressing the problem of high-density catalyst particles easily depositing and the need for high-speed rotation in traditional devices to maintain suspension, this invention features a multi-ring concentric jet tube array at the bottom of the vessel. Driven by an independent high-pressure pulse pump 201, the jet is ejected upwards from the nozzle at high speed. The jet employs a periodic pulse pattern, generating dynamic disturbances that lift the deposited particles and fluidize the entire vessel. The jet tubes are distributed concentrically, with a larger jet angle in the inner ring to promote upward flow at the center and a smaller jet angle in the outer ring to scour the vessel wall area, ensuring no dead zones. The particle suspension state is entirely determined by the jet parameters and is completely decoupled from the stirring speed. Even when the stirring shaft operates at low speed, high-density particles can still maintain uniform suspension, significantly reducing the amount of deposited particles at the bottom of the vessel and keeping the solids content deviation at different heights within a very small range.

[0035] In this embodiment, the pulse jet suspension mechanism 200 serves to maintain particle suspension in a liquid-solid high-solids-content system. The pulse frequency needs to match the sedimentation-resuspension timescale of the solid particles, and the pulse width needs to ensure that the energy of a single jet is sufficient to lift the deposited high-density particle layer. It can be further upgraded to a multi-mode pulse strategy with independent group control. Different pulse frequencies, pulse widths, and phase sequences are executed according to the deposition state of different regions at the bottom of the vessel. For example, high-frequency short pulses in the central region maintain the suspension of fine particles, while low-frequency long pulses in the edge region flush the wall deposition. Alternatively, each group can be sprayed in sequence to form a rotating push-broom effect, thereby achieving fine suspension control with dual spatial and temporal decoupling.

[0036] like Figure 1 As shown, the differential speed stirring mechanism 300 includes a main stirring frame 301, a planetary differential speed stirring assembly 302, an inner stirring shaft 304, and an outer stirring shaft 305. The inner stirring shaft 304 is nested inside the outer stirring shaft 305. The outer stirring shaft 305 is connected to the main stirring frame 301 to drive the main stirring frame 301. The inner stirring shaft 304 is connected to the planetary differential speed stirring assembly 302 to drive the planetary differential speed stirring assembly 302. Two to four groups of planetary differential speed stirring assemblies 302 are evenly distributed around the circumference of the vessel body. Each group of blades rotates and stirs while simultaneously rotating around a hollow shaft.

[0037] In this embodiment, the inner stirring shaft 304 and the outer stirring shaft 305 together form the stirring main shaft. The rotation speed of the inner stirring shaft 304 is 50-100 rpm, and the rotation speed of the outer stirring shaft 305 is 10-60 rpm.

[0038] Furthermore, the outer side of the planetary differential stirring assembly 302 is provided with multiple composite toothed combs 303 along the vertical direction, and the interval between two adjacent composite toothed combs 303 is 5 to 12 mm.

[0039] like Figure 3 As shown, the composite comb 303 includes a comb body 3031, with multiple protrusions 3032 evenly distributed around its outer periphery. The height of each protrusion 3032 is 0.2–0.5 mm. An elastic connector 3033 is provided at the root of each tooth of the comb body 3031, enabling a flexible connection between the comb body 3031 and the impeller 306. The angle can be adaptively adjusted according to the rheological characteristics of the slurry. The composite comb 303 continuously peels away the passivation layer on the catalyst surface through microscopic collisions to improve catalytic efficiency.

[0040] In this embodiment, the working principle of the differential drive stirring mechanism 300 is as follows: Addressing the issues of insufficient shear force at low speeds and easy passivation and deactivation of the catalyst surface, this invention employs a dual-shaft composite drive structure: the outer stirring shaft 305 drives the main stirring frame 301 at a lower speed to provide macroscopic circulating flow, while the inner stirring shaft 304 achieves a composite motion of revolution and rotation via the planetary differential stirring assembly 302 at a higher speed. The blades 306 of the planetary differential stirring assembly 302 are equipped with a comb-micro-convex composite structure—the comb teeth generate high-frequency cutting and breaking of particle agglomerates; the micro-protrusions distributed on the surface collide with the catalyst particles, continuously peeling off the surface passivation layer and exposing a fresh reaction interface. By adjusting the speed difference between the inner and outer shafts, the surface renewal rate can be controlled online, significantly reducing the passivation layer coverage on the catalyst surface and maintaining or even increasing the specific surface area.

[0041] like Figure 1 and Figure 4As shown, the static hydraulic cavitation mechanism 400 includes an external circulation pump 401, a fixed dispersion toothed ring 403, a venturi tube 404, and a cavitation disk 405. The cavitation disk 405 is fixed to the top of the reactor 100. The venturi tube 404 is mounted on the cavitation disk 405 and includes a spiral contraction-expansion channel. The venturi tube 404 is connected to the external circulation pump 401, which is located outside the reactor 100, through a second air inlet pipe 402. When the external circulation pump 401 pressurizes and feeds fly ash slurry into the venturi tube 404, microbubbles are formed to achieve partial hydraulic cavitation. The fixed dispersion toothed ring 403 is located at the outlet of the cavitation disk 405 for secondary shearing and breaking up of the slurry containing cavitation bubbles. The static cavitation unit is completely decoupled from the stirring speed, and the cavitation intensity is independently controlled by the external circulation pump. This allows the cavitation to promote free radical generation while avoiding the destruction of cavitation bubbles by stirring, achieving synergistic effects.

[0042] In this embodiment, the working principle of the static hydraulic cavitation mechanism 400 is as follows: Addressing the issues of short free radical lifetime and the mutual constraints between traditional cavitation and stirring, this invention features a fixed annular cavitation disk 405 at the top of the reactor 100. A spiral contraction-expansion channel is formed on the disk to create a Venturi tube 404. An external circulation pump 401 pressurizes the slurry and delivers it into the cavitation disk 405. As the slurry flows at high speed through the contraction section, the pressure decreases to below the saturated vapor pressure, inducing the formation of cavitation bubble nuclei. Upon entering the expansion section, the pressure surges, causing the cavitation bubbles to collapse instantaneously, generating a local extreme physical field that breaks down water molecules to generate highly reactive species such as hydroxyl radicals. The outlet of the cavitation disk 405 is equipped with a fixed dispersion toothed ring 403, which performs secondary shearing on the bubble-containing slurry, breaking large bubbles into micron-sized bubbles. This significantly increases the gas-liquid contact area and substantially improves the free radical yield. The cavitation intensity is independently controlled by the circulation pump and is completely decoupled from the stirring speed, thus utilizing the efficient free radical generation capability of cavitation while avoiding the damage to the cavitation bubbles caused by stirring.

[0043] The three-layer structure achieves spatiotemporal synergy based on functional decoupling: After the bottom jet establishes a uniform particle distribution, the comb-micro-convex structure of the middle-layer planetary stirrer performs high-frequency shearing and surface activation on the suspended particles, forming a virtuous cycle of "suspension-activation-re-suspension"; the free radicals generated by the top cavitation disk are rapidly transported to the entire reactor under the macroscopic circulation of the middle-layer stirrer, while the microscopic turbulence generated by the comb structure shortens the mass transfer distance of free radicals to the surface of contaminants; the frictional heat generated by low-speed stirring is much lower than that of traditional high-speed stirring, and combined with an external heat exchanger, precise temperature control can be achieved, providing a stable thermodynamic environment for the free radical reaction. The control system automatically switches the operating mode according to real-time monitoring parameters—the suspension start-up mode quickly establishes particle distribution, the reaction maintenance mode maintains minimum energy consumption, and the enhanced treatment mode maximizes free radical generation, achieving intelligent and precise control throughout the entire process.

[0044] In this embodiment, high shear mass transfer is achieved under low spindle speed conditions by decoupling and controlling three major functions: particle suspension, micro-shearing, and cavitation enhancement. The steps include: (1) In the suspension start-up mode, the high-frequency jet pulse is used in conjunction with the rotation speed of the outer stirring shaft 305 at 40-60 rpm and the rotation speed of the inner stirring shaft 304 at 70-100 rpm to quickly establish particle suspension.

[0045] (2) In reaction maintenance mode, the continuous low flow jet is used in conjunction with the rotation speed of the outer stirring shaft 305 at 30-40 rpm and the rotation speed of the inner stirring shaft 304 at 50-70 rpm to maintain the minimum suspension energy consumption.

[0046] (3) In the enhanced treatment mode, the jet is turned off, and the outer stirring shaft 305 rotates at 30-50 rpm and the inner stirring shaft 304 rotates at 80-100 rpm in conjunction with the cavitation disk running at full speed to enhance the generation of free radicals.

[0047] In this embodiment, the three main functions are separated and each is handled by an independent unit—the bottom pulse jet is responsible for particle suspension, allowing the main shaft to operate at a low speed of 10-100 rpm; the differential-driven comb teeth... The micro-convex composite impeller continuously strips the passivation layer from the catalyst surface through microscopic collisions, achieving in-situ mechanical activation. The static hydraulic cavitation mechanism 400, completely decoupled from the stirring, independently generates hydroxyl radicals, which are then transported to the entire reactor by the macroscopic circulating flow field. As a result, superior mass transfer efficiency and pollutant degradation effects are achieved compared to conventional high-speed stirring under low-speed and low-wear conditions, completing a paradigm shift from forced mixing in dynamic equipment to enhanced flow field in static equipment.

[0048] Example 2 In this embodiment, the hydrothermal detoxification device for municipal solid waste incineration fly ash from Example 1 is used to treat the incineration fly ash (pH=12.15, initial dioxin concentration 131 ng-TEQ / kg) after washing of municipal solid waste. The liquid-to-solid ratio is 1:2, and the treatment scale is 5m³. 3 / batch. The system parameters of the hydrothermal detoxification device were set as follows: the external stirring shaft 305 rotated at 45 rpm, the internal stirring shaft 304 rotated at 75 rpm (in the same direction), the jet velocity of the pulse jet suspension mechanism 200 was 12 m / s, the pulse period was 30 s, the pulse width was 6 s, the circulation flow rate of the static hydraulic cavitation mechanism 400 was 25 m3 / h, the inlet pressure was 0.7 MPa, the device was connected in series in two stages, the reaction conditions were 160℃, 120 min, and the detoxifying agent dosage was 5%. The treatment effect was: bottom sediment <2.5%, solid content deviation ±3.2%, dioxin degradation rate 99.1%, and heavy metal leaching concentration better than the national standard limit.

[0049] Example 3 In this embodiment, the same batch of washed fly ash as in Example 2 was treated, with reaction conditions of 160°C, 90 min, and a detoxifying agent dosage of 5%. The effect of different rotation speed combinations on the treatment effect was investigated.

[0050] (1) Experimental setup: The hydrothermal detoxification device for fly ash from municipal solid waste incineration in Example 1 was used. The speed of the outer stirring shaft 305 was 40 rpm, the speed of the inner stirring shaft 304 was 80 rpm, the jet was turned on, and the cavitation was turned on.

[0051] (2) Low-speed control group setting: The hydrothermal detoxification device for fly ash from municipal solid waste incineration in Example 1 was used. The speed of the outer stirring shaft 305 was 40 rpm, the speed of the inner stirring shaft 304 was 0 rpm (no planetary rotation), the jet was turned on, and the cavitation was turned on.

[0052] (3) High-speed control group: a traditional single-shaft stirring reaction device was used, with a stirring shaft speed of 150 rpm, no jet, and no cavitation.

[0053] The treatment results showed that the leaching concentrations of heavy metals in all three groups met the national standard limits. Specifically, the experimental group achieved a dioxin degradation rate of 98.7% and a particle deposition rate of 2.1%; the low-speed control group achieved a dioxin degradation rate of 82.3% and a particle deposition rate of 8.7%; and the high-speed control group achieved a dioxin degradation rate of 85.1% and a particle deposition rate of 12.3%. These results demonstrate that the hydrothermal detoxification device for municipal solid waste incineration fly ash of this invention achieves the highest treatment efficiency under low-speed conditions, verifying the effectiveness of the planetary differential shear structure.

[0054] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A hydrothermal detoxification device for fly ash from municipal solid waste incineration, characterized in that, The system includes a reactor (100), a pulse jet suspension mechanism (200), a differential speed stirring mechanism (300), and a static hydraulic cavitation mechanism (400). The pulse jet suspension mechanism (200) is located at the lower part of the reactor (100) to maintain fluidization throughout the reactor. The differential speed stirring mechanism (300) is located in the middle of the reactor (100) to perform high-frequency shearing and surface activation on suspended particles. The static hydraulic cavitation mechanism (400) is located at the upper part of the reactor (100) to enhance the hydraulic cavitation effect and improve the material reaction rate. The pulse jet suspension mechanism (200), the differential speed stirring mechanism (300), and the static hydraulic cavitation mechanism (400) are all connected to an external control system for independent decoupled control.

2. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 1, characterized in that, The pulse jet suspension mechanism (200) includes a high-pressure pulse pump (201) disposed outside the reactor (100) and a multi-layer concentrically arranged jet ring disposed at the bottom of the reactor (100), wherein multiple jet nozzles (206) are evenly distributed on the jet ring; the high-pressure pulse pump (201) is connected to the jet ring through a first air inlet pipe (202).

3. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 2, characterized in that, The multi-layer concentrically arranged jet rings include an upper jet ring (203), a middle jet ring (204), and a lower jet ring (205) with successively decreasing diameters. The upper jet ring (203) is close to the bottom of the differential transmission stirring mechanism (300), and the lower jet ring (205) is close to the discharge port at the bottom of the reactor (100).

4. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 3, characterized in that, The jet nozzles (206) are distributed at an angle of 30° to 60° toward the top of the reactor (100), and the inclination angles of the jet nozzles (206) on the upper jet ring (203), the middle jet ring (204) and the lower jet ring (205) increase sequentially.

5. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to any one of claims 1 to 4, characterized in that, The differential transmission stirring mechanism (300) includes a main stirring frame (301), a planetary differential stirring assembly (302), an inner stirring shaft (304), and an outer stirring shaft (305); the inner stirring shaft (304) is nested inside the outer stirring shaft (305), the outer stirring shaft (305) is connected to the main stirring frame (301) to drive the main stirring frame (301), and the inner stirring shaft (304) is connected to the planetary differential stirring assembly (302) to drive the planetary differential stirring assembly (302).

6. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 5, characterized in that, The inner stirring shaft (304) rotates at a speed of 50 to 100 rpm, and the outer stirring shaft (305) rotates at a speed of 10 to 60 rpm.

7. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 5, characterized in that, The planetary differential stirring assembly (302) has multiple composite toothed combs (303) arranged vertically on the outer side of the blades (306), and the interval between two adjacent composite toothed combs (303) is 5 to 12 mm.

8. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to claim 7, characterized in that, The composite comb (303) includes a comb body (3031), the comb body (3031) has a plurality of protrusions (3032) evenly distributed on its outer periphery, and an elastic connector (3033) is provided at the root of the teeth of the comb body (3031), the elastic connector (3033) being connected to the blade (306).

9. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to any one of claims 1 to 4, characterized in that, The static hydraulic cavitation mechanism (400) includes an external circulation pump (401), a fixed dispersion toothed ring (403), a venturi tube (404), and a cavitation disc (405). The cavitation disc (405) is fixed to the top of the reactor (100). The venturi tube (404) is installed on the cavitation disc (405). The venturi tube (404) is connected to the external circulation pump (401) installed outside the reactor (100) through a second air inlet pipe (402). When the external circulation pump (401) pressurizes and sends fly ash slurry into the venturi tube (404), microbubbles are formed to achieve partial hydraulic cavitation. The fixed dispersion toothed ring (403) is installed at the outlet of the cavitation disc (405) to perform secondary shearing and crushing on the slurry containing cavitation bubbles.

10. The hydrothermal detoxification device for fly ash from municipal solid waste incineration according to any one of claims 1 to 4, characterized in that, The inner wall of the reactor (100) is provided with spirally distributed guide strips (101) with adjustable inclination angles, the inclination angle of the guide strips (101) being 15° to 30°.

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