Belt type multi-stage countercurrent fly ash washing system

Abstract

The invention relates to the technical field of fly ash washing, in particular to a belt type multistage countercurrent fly ash washing system which comprises a fly ash storage tank, and grid plates which are used for filtering and are horizontally distributed are further arranged in a stirring tank; one side of the top end of the stirring tank is connected with a liquid conveying pipe; a detection piece is also arranged in the stirring tank; a conveying mechanism is further arranged on the right upper side of the stirring tank and comprises a supporting frame, a driving roller, a driven roller, a vibrating carrier roller, a conveying belt and an adjusting part; the conveying belt is further provided with wave-shaped blocking edges which are symmetrically distributed front and back, and a filtering plate is further fixedly installed between the two wave-shaped blocking edges. The adjusting piece is used for dividing the conveying belt into a horizontal section and an inclined section and can complete adjusting operation of different inclination angles. A plurality of rapping carrier rollers are uniformly distributed, and uniformly distributed bulges are arranged on the rapping carrier rollers. The number of washing and filter pressing equipment is reduced, the process is simple, the cost is reduced, a multi-layer countercurrent washing structure is adopted, tiling is avoided, the structure is compact, and the occupied land cost is low.

Description

Technical Field

[0001] This invention relates to the field of fly ash washing technology, specifically to a belt-driven multi-stage countercurrent fly ash washing system. Background Technology

[0002] Fly ash from waste incineration is fine particulate matter collected by the flue gas purification system during the waste incineration process, and its production has increased dramatically with the rapid development of the waste incineration industry. Fly ash contains harmful substances such as heavy metals (e.g., lead, cadmium, mercury), dioxins, and large amounts of water-soluble salts (especially chlorides, which typically account for over 50%). If these components are discharged directly without effective treatment or improperly disposed of, they will cause serious pollution to the soil, water bodies, and atmosphere, and also threaten human health through the food chain.

[0003] Currently, the main methods for disposing of fly ash from waste incineration include landfill disposal and co-processing in cement kilns. Landfill disposal faces challenges such as high disposal pressure and significant land occupation due to the large volume of fly ash generated and scarce land resources in large and medium-sized cities. While co-processing in cement kilns is widely advocated, the soluble chloride content in fly ash from waste incineration in my country is generally high. Direct injection into cement kilns for co-processing is only suitable for fly ash with a chloride ion content of less than 3%, and improper control of the feed rate can easily cause problems such as scaling inside the kiln, equipment corrosion, and pipeline blockage. Furthermore, the high chloride content material generated from bypass ventilation is also difficult to effectively dispose of. Fly ash washing is a common method for removing water-soluble salts, especially chloride ions, from fly ash. Multi-stage countercurrent washing technology, by dividing the washing process into multiple stages—using low-concentration liquid to wash low-salt ash and high-concentration brine to wash high-salt ash—effectively reduces the liquid-to-solid ratio and improves washing efficiency. However, existing multi-stage countercurrent washing technologies for fly ash still have several drawbacks: countercurrent washing often requires three or more sets of washing agitation and solid-liquid separation equipment, resulting in excessive equipment usage, large footprint, high equipment costs, and long investment recovery periods. Furthermore, existing processes lack precise control over agitation intensity and water consumption during washing, making it difficult to achieve optimal washing results. This leads to high energy consumption and high processing costs, limiting the further promotion and application of multi-stage countercurrent washing technology for fly ash.

[0004] Further detailed analysis of the defects and shortcomings of existing technologies: 1. Existing multi-stage countercurrent water washing processes and devices for fly ash mostly adopt a graded "water washing + filter press + crushing" process. The number of water washings corresponds one-to-one with the number of filter presses and crushings. This configuration results in too many filter presses, complicated processes, and increased costs. 2. Existing multi-stage countercurrent water washing processes and devices for fly ash mostly adopt a "flat layout", which is complex in structure, and the water tanks and other equipment occupy a large area, resulting in high land costs and making it difficult to meet the actual situation of insufficient space for renovation. 3. Existing multi-stage countercurrent water washing processes and devices for fly ash do not employ professional measuring equipment such as online salinity meters and online sludge concentration meters. Although the countercurrent water washing process is completed, it is unknown whether the Na, K, and Cl ions in the final effluent are saturated. If not saturated, it will result in a waste of water resources and increased costs. If saturation is not achieved in the final water washing stage, it will affect the desalination effect of the water washing and may affect the resource utilization products of the fly ash downstream (such as aggregates, ceramsite, concrete admixtures, etc.) (which have requirements for fly ash salt content). Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing multi-stage countercurrent water washing processes, this invention provides a belt-driven multi-stage countercurrent fly ash water washing system that reduces the number of water washing and filter press equipment, simplifies the process, reduces costs, adopts a multi-layer water washing structure to avoid flat laying, has a compact structure, low footprint and cost, and greatly improves the efficiency of fly ash water washing operations.

[0006] The present invention achieves the above objectives by adopting the following technical solution: A belt-driven multi-stage countercurrent fly ash washing system includes a fly ash storage tank. The input end of the fly ash storage tank is connected to an external fly ash source via a feed pipe, and the output end is connected to a mixing tank via a discharge pipe. The mixing tank is vertically arranged and has a cover plate at the top. Horizontally distributed grid plates are also provided inside the mixing tank. A stirring motor is mounted on the cover plate via a bracket. The output shaft of the stirring motor is connected to a vertically distributed stirring shaft, which is equipped with stirring blades. A liquid delivery pipe is connected to one side of the top of the mixing tank, and a drain pipe is connected to one side of the bottom. A detection device is also provided inside the mixing tank to detect the chloride ion content in the solution and to provide visual and automatic release of the upper liquid layer. A conveying mechanism is also provided on the upper right side of the mixing tank. The conveying mechanism includes a support frame, a driving roller, a driven roller, a vibrating roller, a conveyor belt, and an adjusting component. The support frame is vertically arranged, and the driving roller is rotatably mounted on the left side of the support frame and connected to a drive motor. The driven roller is rotatably mounted on the right side of the support frame. The conveyor belt is positioned between the driving roller and the driven roller. The conveyor belt is also equipped with symmetrically distributed corrugated sidewalls, and a filter plate is fixedly installed between two of the corrugated sidewalls. The adjusting component is used to divide the conveyor belt into horizontal and inclined sections, and can perform different inclination angle adjustments. There are multiple evenly distributed vibrating rollers, all mounted on the support frame and located in the inclined section. The vibrating rollers are equipped with evenly distributed protrusions. An inclined water collection trough is also provided on the support frame and below the conveyor belt. A sludge storage tank is also provided below the end of the inclined section. The output end of the sludge storage tank is connected to a filter press through a transport pipe. One end of the filter press is also connected to a liquid storage tank B through a transfer pipe, and the output end is also connected to a screw conveyor. The liquid storage tank B directs water flow to the inclined section through a return pipe. A clean water filling structure is also provided on one side of the support frame to complete the water replenishment operation for the fly ash washing operation in the inclined section.

[0007] As a preferred technical solution: a manual slide gate valve is also provided on the discharge pipe, and a rotary valve is also provided on the discharge pipe and below the manual slide gate valve.

[0008] A further preferred technical solution: the connection points between the stirring shaft and the cover plate and the grid plate are each equipped with a sealed ball bearing; the infusion pipe is also equipped with a ball valve, an electromagnetic flow meter, an electric valve and a ball valve in sequence from left to right; the sewage pipe is also equipped with a ball valve, a sludge pump and a ball valve in sequence from left to right, and the output end of the sewage pipe leads to the horizontal section.

[0009] A further preferred technical solution: The detection device includes an online chloride ion salinity meter, an LED display screen, and a drain pipe; the online chloride ion salinity meter is fixedly installed inside the mixing tank by a bracket and located above the grid plate, and the LED display screen is located on the outside of the mixing tank; a ball valve, an electric valve, and another ball valve are sequentially installed on the drain pipe from left to right; the online chloride ion salinity meter is connected to the LED display screen and the electric valve on the drain pipe respectively; the output end of the drain pipe is also sequentially connected to a sedimentation tank and a storage tank A, so that the solution with completely saturated chloride ions eventually flows to the MVR.

[0010] A further preferred technical solution: a splash guard is provided on one side of the mixing tank, and a diversion plate is provided on the lower left of the water collection tank. The splash guard and the diversion plate together form a liquid flow channel, and the output end of the liquid flow channel finally leads to the mixing tank.

[0011] As a preferred technical solution: the filter plate includes a horizontal partition frame and a filter screen disposed within the horizontal partition frame; wherein the mesh size of the filter screen is such that water can pass through but fly ash cannot during the solid-liquid mixing after each stage of water washing.

[0012] As a preferred technical solution: the adjusting component includes a lower idler roller, an upper idler roller, a U-shaped frame, and a hydraulic cylinder; both the upper and lower idler rollers are mounted on the support frame and are located at the inflection point between the horizontal and inclined sections. The lower idler roller maintains surface contact with the inner wall of the lower conveyor belt, while the upper idler roller maintains surface contact with the outer edge of the upper end face of the upper conveyor belt. Furthermore, the upper idler roller and the filter plate do not interfere with each other. The U-shaped frame is mounted on the driven roller. One end of the hydraulic cylinder is rotatably mounted on the support frame, and the other end is rotatably mounted on the U-shaped frame. The inclination angle of the inclined section is 0-15 degrees.

[0013] As a preferred technical solution: a ball valve, a sludge pump, and a ball valve are sequentially installed on the transport pipe along the output direction; a ball valve, an electric valve, and a ball valve are sequentially installed on the transfer pipe along the output direction; a ball valve, a liquid pump, an electric valve, and a ball valve are sequentially installed on the return pipe along the output direction; and an air knife is also provided on the support frame below the end of the inclined section.

[0014] A further preferred technical solution: The liquid storage tank B is also provided with baffles and filter elements. The baffles are two distributed vertically and in a ring shape, forming an installation cavity between them. The filter element includes activated carbon particles, air filter cotton and non-woven fabric distributed sequentially from the inside to the outside.

[0015] A further preferred technical solution: The clean water filling structure includes a clean water pipeline and ball valves, electromagnetic flow meters, electric valves and ball valves arranged sequentially on the clean water pipeline; the output ends of the clean water pipeline and the return pipe are both oriented towards the middle and upper part of the inclined section.

[0016] The beneficial effects of this invention compared to the prior art are as follows: 1. By optimizing the design and improving the new water washing technology, this invention only sets up one filter press and water washing process, which greatly reduces the number of water washing and filter press equipment. The process is simple and the cost is reduced. It solves the problem that the traditional fly ash water washing technology uses a multi-stage countercurrent water washing process and equipment that adopts a graded "water washing + filter press + crushing" process. The number of water washings corresponds one-to-one with the number of filter presses and crushings. Such a configuration leads to too many filter press equipment, complicated processes, and increased costs.

[0017] 2. This invention, through innovative design of a novel belt structure, introduces a new belt-driven multi-stage counter-current water washing technology. The technology features a rational spatial arrangement and a multi-layer counter-current water washing structure, avoiding flat layouts, resulting in a compact structure and low footprint. It primarily addresses the challenges of existing fly ash multi-stage counter-current water washing processes and devices, which often employ a "flat" layout, resulting in complex structures, large water tanks and other equipment footprints, high costs, and difficulty in meeting the practical needs of limited modification space. In actual process applications, this invention can handle situations with limited on-site modification space, making it more adaptable.

[0018] 3. This invention incorporates an "online chloride ion detector" at the mixing tank to monitor the chloride ion content in the solution. Once the chloride ion content reaches its peak, the upper layer of liquid in the agitator is released and, after multiple processing steps, is sent to the MVR for salt separation. Simultaneously, fresh water is added to the mixing tank to dilute the chloride ion concentration, and the process is repeated until the chloride ion content reaches its peak. This ensures that the liquid going to the MVR is completely saturated with chloride ions. A saturated state saves water compared to an unsaturated state, directly reducing the energy consumption of MVR evaporation and crystallization. Furthermore, the online chloride ion salinity meter prevents the solution from being washed even after it has become oversaturated with chloride ions. This avoids the problem of reduced chloride ion removal efficiency in fly ash washing, which would fail to meet the requirements for chloride ion content in fly ash for resource utilization, leading to rework and increased costs. Therefore, while ensuring and improving the fly ash washing effect, this invention also achieves the goals of rational resource utilization and energy conservation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a perspective view of the overall structure of the present invention; Figure 2 This is a schematic diagram illustrating the overall structural working principle of the present invention; Figure 3This is a schematic diagram of the internal structure of the mixing tank of the present invention; Figure 4 This is a simplified diagram illustrating the connection principle of the mixing tank of the present invention; Figure 5 This is a partial structural diagram of the conveying mechanism of the present invention; Figure 6 This is a structural diagram of the filter plate of the present invention; Figure 7 This is a schematic diagram of the structure of the vibrating roller of the present invention; Figure 8 This is a schematic diagram of the structure of the liquid storage tank B of the present invention; Figure 9 This is a partial structural diagram of the conveying mechanism of the present invention.

[0021] In the diagram: 1. Fly ash storage tank; 101. Feed pipe; 102. Discharge pipe; 103. Manual slide gate valve; 104. Rotary valve; 2. Mixing tank; 201. Cover plate; 202. Grid plate; 203. Mixing motor; 204. Mixing shaft; 205. Mixing blade; 206. Infusion pipe; 207. Sewage pipe; 208. Ball valve; 209. Electromagnetic flow meter; 210. Electric valve; 211. Sludge pump; 212. Splash shield; 213. Drain plate; 214. Liquid flow channel; 215. Air knife; 216. Liquid pump; 3. Detection components; 301. Online chloride ion salinity meter; 302. LED display screen; 303. Drain pipe; 304. Sedimentation tank; 305. Storage tank A; 306. Flip plate; 4. Conveying mechanism; 401. Support frame; 40 2. Driven roller; 403. Driven roller; 404. Vibrating roller; 405. Conveyor belt; 406. Adjusting component; 407. Drive motor; 408. Corrugated sidewall; 409. Filter plate; 410. Horizontal section; 411. Inclined section; 412. Protrusion; 413. Water collection tank; 414. Horizontal partition frame; 415. Filter screen; 416. Lower roller; 417. Upper roller; 418. U-shaped frame; 419. Hydraulic cylinder; 5. Sludge storage tank; 501. Transport pipe; 6. Filter press equipment; 601. Transfer pipe; 7. Liquid storage tank B; 701. Return pipe; 702. Baffle; 703. Filter element; 704. Activated carbon granules; 705. Air filter cotton; 706. Non-woven fabric; 8. Screw conveyor; 9. Clean water filling structure; 901. Clean water pipeline. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that, in specific embodiments of the present invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the use of phrases such as "comprising one" to define an element does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "equipped" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example: Figures 1 to 9 As shown: A belt-driven multi-stage countercurrent fly ash washing system includes a fly ash storage tank 1, such as... Figure 1 As shown, the fly ash storage tank has an inverted structure, with the input at the top and the output at the bottom. Specifically, it can be elevated using a base frame to provide sufficient space for the subsequent installation of the mixing tank. The input end of the fly ash storage tank 1 is connected to an external fly ash source via a feed pipe 101, and the output end is connected to the mixing tank 2 via a discharge pipe 102; the discharge pipe is vertically aligned and leads to the mixing tank. A manual slide valve 103 is also provided on the discharge pipe 102, and a rotary valve 104 is located on the discharge pipe 102 and below the manual slide valve 103. This arrangement facilitates control of the fly ash feed.

[0026] like Figure 3As shown: In this embodiment, the mixing tank 2 is vertically arranged and has a cover plate 201 at the top. A horizontally distributed grid plate 202 is also provided inside the mixing tank 2, and the grid plate is fixedly connected to the inner wall of the mixing tank via a slot. A stirring motor 203 is also mounted on the cover plate 201 via a bracket. The output shaft of the stirring motor 203 is connected to a vertically distributed stirring shaft 204, and stirring blades 205 are provided on the stirring shaft 204. With this arrangement, when the stirring motor starts, it drives the stirring shaft and stirring blades to stir the fly ash mixture. Sealed ball bearings are provided at the connections between the stirring shaft 204 and the cover plate 201 and the grid plate 202, respectively; the purpose of this arrangement is to ensure normal stirring operation while improving the sealing effect of the connections. Figure 4 As shown: From left to right, the infusion tube 206 is also equipped with a ball valve 208, an electromagnetic flow meter 209, an electric valve 210, and another ball valve 208. The infusion tube is used to add clean water. Figure 1 As shown: A splash guard 212 is also provided on one side of the mixing tank 2, specifically near the conveyor belt; this prevents water from flowing down and splashing, ensuring environmental hygiene. A flow guide plate 213 is also provided on the lower left side of the water collection tank 413. The splash guard 212 and the flow guide plate 213 together form a liquid flow channel 214, the output end of which leads to the mixing tank 2. This arrangement facilitates the centralized collection and recycling of liquid from the multi-stage counter-current washing process, allowing it to be further processed in the mixing tank. It also collects water droplets falling from the conveyor belt during its return journey, keeping the equipment clean and tidy, while simultaneously recycling the water back to the mixing tank for reuse.

[0027] like Figure 4 As shown: In this embodiment, a liquid infusion pipe 206 is connected to one side of the top of the mixing tank 2, and a drain pipe 207 is connected to one side of the bottom; the liquid infusion pipe is used to replenish clean water. The drain pipe is used to discharge the fly ash after stirring and settling. A ball valve 208, a sludge pump 211, and another ball valve 208 are also installed on the drain pipe 207 from left to right. This arrangement ensures the output of fly ash sediment. The output end of the drain pipe 207 leads to the horizontal section 410, which serves as the initial stage of multi-stage fly ash washing. The mixing tank 2 is also equipped with a detection element 3 to detect the chloride ion content in the solution and provide a visual and automatic function for releasing the upper liquid. Figure 2 and Figure 3As shown: In a preferred embodiment, the detection element 3 includes an online chloride ion salinity meter 301, an LED display screen 302, and a drain pipe 303. The online chloride ion salinity meter 301 is fixedly installed inside the mixing tank 2 by a bracket and is located above the grid plate 202, used to detect the chloride ion content in the solution. The LED display screen 302 is located on the outside of the mixing tank 2; a ball valve 208, an electric valve 210, and another ball valve 208 are also installed sequentially from left to right on the drain pipe 303. The online chloride ion salinity meter 301 maintains signal connection with the LED display screen 302 and the electric valve 210 on the drain pipe 303, which can be automated by connecting to a PLC controller. The LED display screen is used to display the chloride ion content parameter of the solution in the mixing tank in real time. Figure 1 and Figure 2 As shown: The output end of the drain pipe 303 is also connected in sequence to a sedimentation tank 304 and a storage tank A305, ensuring that the solution, fully saturated with chloride ions, ultimately flows to the MVR. The sedimentation tank 304 is equipped with a flap 306, a solid structure, vertically distributed and shorter than the height of the sedimentation tank 304, used to achieve sedimentation, filtration, and interception of fly ash impurities. When the online chloride ion salinity meter detects that the chloride ion content in the solution has reached its peak, the electric valve on the drain pipe is opened, releasing the upper layer of static liquid from the mixing tank. After multiple processing steps, the liquid is sent to the MVR for salt separation. Simultaneously, fresh water is added to the mixing tank to dilute the chloride ion concentration, and a countercurrent multi-stage water wash is performed on the conveyor belt until the chloride ion content reaches its peak, repeating this process. This ensures that the liquid going to the MVR is fully saturated with chloride ions. MVR, or fly ash water washing and desalination, is a device used to treat fly ash from waste incineration. Its main purpose is to remove chloride ions from the fly ash and convert it into cement clinker and industrial salt through a cement kiln co-processing system.

[0028] like Figure 1 and Figure 2As shown: In this embodiment, a conveying mechanism 4 is also provided on the upper right side of the mixing tank 2. The conveying mechanism 4 includes a support frame 401, a driving roller 402, a driven roller 403, a vibrating idler roller 404, a conveyor belt 405, and an adjusting component 406. The support frame 401 is vertically distributed. The driving roller 402 is rotatably disposed on the left side of the support frame 401 and is connected to a drive motor 407. The drive motor is a variable frequency motor and can also be connected to a reducer to adjust and set the belt running speed. In this embodiment, considering both the safe conveying of the belt and the efficiency of fly ash washing, the speed at which the drive motor drives the conveyor belt is slow enough to meet the effect of multi-stage fly ash washing. The driven roller 403 is rotatably disposed on the right side of the support frame 401 to support and drive the conveyor belt. The conveyor belt 405 is positioned between the driving roller 402 and the driven roller 403. The conveyor belt 405 also features symmetrically distributed corrugated sidewalls 408. These sidewalls are positioned within the conveyor belt, leaving a gap between them and the outer end wall of the belt, serving as open edges. The conveyor belt acts as the carrier for transportation and washing, and it adopts the corrugated sidewall conveyor belt standard HG / T 4062-2023. Further structural optimization and upgrades are made to the belt by fixing a filter plate 409 between the two corrugated sidewalls 408; the two are fixed and sealed to prevent liquid from flowing out through the gap. Figure 6 As shown: The filter plate 409 includes a horizontal partition frame 414 and a filter screen 415 disposed within the horizontal partition frame 414; wherein the mesh size of the filter screen 415 is such that water can pass through but fly ash cannot during the solid-liquid mixing after each stage of water washing.

[0029] like Figure 1 , Figure 2 and Figure 9 As shown: In this embodiment, the adjusting member 406 is used to divide the conveyor belt 405 into a horizontal section 410 and an inclined section 411, and can complete the adjustment operation of different inclination angles; the inclined section is the main part of the multi-stage countercurrent water washing of fly ash. Figure 5As shown: In a preferred embodiment, the adjusting component 406 includes a lower idler roller 416, an upper idler roller 417, a U-shaped frame 418, and a hydraulic cylinder 419. Both the upper idler roller 417 and the lower idler roller 416 are mounted on the support frame 401, located at the inflection point between the horizontal section 410 and the inclined section 411. The lower idler roller 416 maintains surface contact with the inner wall of the lower conveyor belt 405, while the upper idler roller 417 maintains surface contact with the outer edge of the upper end face of the upper conveyor belt 405. The upper idler roller 417 is relatively short and does not interfere with the filter plate 409; that is, the upper idler roller is positioned at the empty edge of the conveyor belt, used to press and limit the movement of the belt at bends. The U-shaped frame 418 is mounted on the driven roller 403. One end of the hydraulic cylinder 419 is rotatably mounted on the support frame 401, and the other end is rotatably mounted on the U-shaped frame 418. In a preferred embodiment, the inclination angle of the inclined section 411 is 0-15 degrees. This arrangement allows for adjustment of the angle between the inclined section and the horizontal section, enabling better testing of the relationship between different fly ash treatment volumes and water flow rates. An air knife 215 is also provided on the support frame 401, below the end of the inclined section 411. This arrangement aims to blow down fly ash slurry that cannot fall down by gravity.

[0030] like Figure 1 and Figure 7 As shown: In this embodiment, there are multiple evenly distributed vibrating rollers 404, all mounted on the support frame 401 and located on the inclined section 411. The vibrating rollers 404 are provided with evenly distributed protrusions 412. The purpose of this arrangement is to create an up-and-down jogging motion on the belt during operation, producing a "vibrating" effect to dislodge fly ash particles clogging the filter screen. Inclined water collection troughs 413 are also provided on the support frame 401 and below the conveyor belt 405 to collect liquids. Figure 1 and Figure 2 As shown: A sludge storage tank 5 is also provided below the end of the inclined section 411, that is, the fly ash slurry that has undergone multi-stage countercurrent water washing is discharged into the sludge storage tank through the inclined section. The output end of the sludge storage tank 5 is connected to a filter press 6 via a transport pipe 501. The filter press is existing technology and is mainly used for solid-liquid separation, so its structure will not be described in detail. One end of the filter press 6 is also connected to a liquid storage tank B7 via a transfer pipe 601, and the output end is also connected to a screw conveyor 8. The liquid storage tank B7 is connected to the inclined section 411 via a return pipe 701; a ball valve 208, a sludge pump 211, and a ball valve 208 are also installed sequentially along the output direction on the transport pipe 501. A ball valve 208, an electric valve 210, and a ball valve 208 are also installed sequentially along the output direction on the transfer pipe 601. Along the output direction, the return pipe 701 is also equipped with a ball valve 208, a liquid pump 216, an electric valve 210, and a ball valve 208 in sequence.

[0031] like Figure 8 As shown: In this embodiment, the storage tank B7 is further provided with baffles 702 and filter elements 703. The baffles 702 are two units distributed vertically in a ring shape, forming an installation cavity between them. The filter element 703 includes activated carbon particles 704, air filter cotton 705, and non-woven fabric 706 arranged sequentially from the inside out. This arrangement is for the purpose of further filtering and purifying the water discharged from the filter press; it also facilitates installation, disassembly, and replacement. Its power source is a liquid pump on the return pipe.

[0032] In this embodiment, a clean water filling structure 9 is also provided on one side of the support frame 401 to complete the water replenishment operation for the fly ash washing operation of the inclined section 411. Thus, the water source for fly ash countercurrent washing is mainly divided into the output of the return pipe and a supplement of clean water filling. In a preferred technical solution, the clean water filling structure 9 includes a clean water pipeline 901 and ball valve 208, electromagnetic flowmeter 209, electric valve 210 and ball valve 208 arranged sequentially on the clean water pipeline 901. The output ends of the clean water pipeline 901 and the return pipe 701 are both oriented towards the upper middle part of the inclined section 411. One end of the clean water pipeline 901 can also be connected to a liquid pump to provide power output for liquid flow transportation. Meanwhile, spray heads can be connected to the output ends of the clean water pipeline and the return liquid pipeline. By adopting this spray structure, the output flushing area of ​​the water can be increased, thereby increasing the disturbance area of ​​the liquid flow on the fly ash. At the same time, the contact area between water and fly ash is increased, allowing the salt in the fly ash to dissolve better and be carried away by the water flow, improving the efficiency of salt removal, reducing water consumption and the number of circulations, and making the entire equipment and even the entire system more efficient, environmentally friendly and green.

[0033] Working principle: Fly ash enters the mixing tank from the fly ash storage tank via a manual gate valve and rotary valve. Simultaneously, water is injected into the mixing tank through the infusion pipe, causing the fly ash and water to come into contact and mix. After being uniformly mixed by the stirring shaft and blades, the fly ash solid-liquid mixture is further agitated by the grid plates, causing larger fly ash particles to gradually settle at the bottom of the tank, forming fly ash slurry. The clearer water flows above the grid plates.

[0034] The next step involves pumping the fly ash slurry settled at the bottom of the mixing tank into a belt-type washing conveyor system via a sludge pump. This conveyor is transported to the horizontal section of the belt, which is initially arranged horizontally and then inclined, running diagonally upwards. Initially, clean water (provided by a clean water pipeline) is injected from above the inclined section of the conveyor belt, flowing downwards while the fly ash slurry flows upwards. Gradually, each filter plate becomes filled with water and fly ash slurry. Simultaneously, due to the gravitational potential energy of the water, the fly ash slurry and water are thoroughly mixed and washed between the filter plates. The washed fly ash slurry is then further washed with water from above, which has a lower chloride ion content. This water then flows into the next filter plate for further washing, and so on, level by level. Overall, on the same belt, from bottom to top, the chloride ion content of the fly ash slurry decreases, while from top to bottom, the chloride ion content of the water increases.

[0035] In this embodiment, an online chloride ion salinity meter is installed inside the mixing tank to detect the chloride ion content in the solution. Once the chloride ion content in the solution reaches its peak, the clear liquid in the upper layer of the mixing tank is released. After undergoing multiple processes according to the process flow diagram, it is sent to the MVR for salt separation. Simultaneously, fresh water is added to the mixing tank to dilute the chloride ion concentration, and a water washing process is performed until the chloride ion content reaches its peak, and this process is repeated. In this embodiment, the conveyor belt adopts the corrugated sidewall conveyor belt in HG / T 4062-2023. The difference is that this industry standard structure has been optimized and upgraded. Specifically, the filter plate is fixed and sealed to the corrugated sidewall to ensure that the liquid does not flow out from the gap in the middle; the mesh size of the filter screen is sufficient to allow water to pass through smoothly in the solid-liquid mixture after each water washing, but not fly ash.

[0036] The water from the multi-stage washing process on the conveyor belt flows into the mixing tank for the next mixing cycle. Clean water supplied to the subsequent mixing tanks via a delivery pipe is used for makeup water. The washed fly ash slurry is initially filtered through a filter screen on the conveyor belt and collected in a sludge storage tank, then pumped to a filter press. The fly ash cake formed by the filter press is conveyed by a screw conveyor to the resource utilization process (aggregate, cement, ceramsite, etc.). Simultaneously, the water from the filter press is transported by the combined action of storage tank B and a pump to the inclined section of the conveyor belt for fly ash washing.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A belt-driven multi-stage countercurrent fly ash washing system, characterized in that: The system includes a fly ash storage tank. The input end of the fly ash storage tank is connected to an external fly ash source via a feed pipe, and the output end is connected to a mixing tank via a discharge pipe. The mixing tank is vertically positioned and has a cover plate at the top. Horizontally distributed grid plates are also installed inside the mixing tank. A stirring motor is mounted on the cover plate via a bracket. The output shaft of the stirring motor is connected to a vertically distributed stirring shaft, which is equipped with stirring blades. A liquid delivery pipe is connected to one side of the top of the mixing tank, and a drain pipe is connected to one side of the bottom. A detection device is also installed inside the mixing tank to detect the chloride ion content in the solution and provide a visual and automatic function to release the upper liquid layer. A conveying mechanism is also located on the upper right side of the mixing tank. The conveying mechanism includes a support frame, a driving roller, a driven roller, a vibrating roller, a conveyor belt, and an adjusting component. The support frame is vertically positioned, and the driving roller is rotatably mounted on the left side of the support frame and connected to a drive motor. The driven roller is rotatably mounted on... Located on the right side of the support frame, the conveyor belt is positioned between the driving roller and the driven roller. The conveyor belt also features symmetrically distributed corrugated sidewalls, with a filter plate fixedly installed between two of the corrugated sidewalls. The adjusting component divides the conveyor belt into horizontal and inclined sections, allowing for adjustments to different inclination angles. Multiple evenly distributed vibrating rollers are positioned on the support frame and located on the inclined section, each with evenly distributed protrusions. An inclined water collection trough is located on the support frame below the conveyor belt. A sludge storage tank is located below the end of the inclined section. The output end of the sludge storage tank is connected to a filter press via a transport pipe. One end of the filter press is connected to a liquid storage tank B via a transfer pipe, and its output end is connected to a screw conveyor. Liquid storage tank B directs water flow to the inclined section via a return pipe. A clean water filling structure is also provided on one side of the support frame to replenish water for the fly ash washing operation on the inclined section.

2. The belt-driven multi-stage countercurrent fly ash washing system as described in claim 1, characterized in that: A manual slide gate valve is also provided on the discharge pipe, and a rotary valve is also provided on the discharge pipe and below the manual slide gate valve.

3. The belt-driven multi-stage countercurrent fly ash washing system as described in claim 1, characterized in that: Sealed ball bearings are provided at the connection points between the stirring shaft and the cover plate and the grid plate respectively; a ball valve, an electromagnetic flow meter, an electric valve and a ball valve are also installed on the infusion pipe from left to right; a ball valve, a sludge pump and a ball valve are also installed on the sewage pipe from left to right, and the output end of the sewage pipe leads to the horizontal section.

4. A belt-driven multi-stage counter-current fly ash washing system as described in claim 3, characterized in that: The detection components include an online chloride ion salinity meter, an LED display screen, and a drain pipe. The online chloride ion salinity meter is fixedly installed inside the mixing tank by a bracket and located above the grid plate. The LED display screen is located on the outside of the mixing tank. From left to right, a ball valve, an electric valve, and another ball valve are installed on the drain pipe. The online chloride ion salinity meter is connected to the LED display screen and the electric valve on the drain pipe. The output end of the drain pipe is connected to a sedimentation tank and a storage tank A, so that the solution with fully saturated chloride ions eventually flows to the MVR. The sedimentation tank is also equipped with a flap, which is vertically distributed and its height is less than the height of the sedimentation tank.

5. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 4, characterized in that: A splash guard is provided on one side of the mixing tank, and a flow guide plate is provided on the lower left side of the water collection tank. The splash guard and the flow guide plate together form a liquid flow channel, and the output end of the liquid flow channel finally leads to the mixing tank.

6. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 1, characterized in that: The filter plate includes a horizontal partition frame and a filter screen disposed within the horizontal partition frame; wherein the mesh size of the filter screen is such that water can pass through but fly ash cannot during the solid-liquid mixing after each stage of washing.

7. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 1, characterized in that: The adjusting components include a lower idler roller, an upper idler roller, a U-shaped frame, and a hydraulic cylinder. Both the upper and lower idler rollers are mounted on the support frame and located at the inflection point between the horizontal and inclined sections. The lower idler roller maintains surface contact with the inner wall of the lower conveyor belt, while the upper idler roller maintains surface contact with the outer edge of the upper end face of the upper conveyor belt. The upper idler roller and the filter plate do not interfere with each other. The U-shaped frame is mounted on the driven roller. One end of the hydraulic cylinder is rotatably mounted on the support frame, and the other end is rotatably mounted on the U-shaped frame. The inclination angle of the inclined section is 0-15 degrees.

8. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 1, characterized in that: A ball valve, a sludge pump, and a ball valve are sequentially installed on the transport pipe along the output direction; a ball valve, an electric valve, and a ball valve are sequentially installed on the transfer pipe along the output direction; a ball valve, a liquid pump, an electric valve, and a ball valve are sequentially installed on the return pipe along the output direction; and an air knife is also provided on the support frame below the end of the inclined section.

9. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 8, characterized in that: The storage tank B is also equipped with baffles and filter elements. There are two baffles distributed vertically and in a ring shape, forming an installation cavity between them. The filter element includes activated carbon particles, air filter cotton and non-woven fabric distributed from the inside to the outside.

10. A belt-driven multi-stage countercurrent fly ash washing system as described in claim 9, characterized in that: The clean water filling structure includes a clean water pipeline and ball valves, electromagnetic flow meters, electric valves, and ball valves arranged sequentially on the clean water pipeline; the output ends of the clean water pipeline and the return pipe are both oriented towards the middle and upper part of the inclined section.

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