Fly ash washing and filtering integrated equipment and fly ash washing and filtering method

Abstract

The invention discloses fly ash washing and filtering integrated equipment and a fly ash washing and filtering method. The fly ash washing and filtering integrated equipment comprises a washing and filtering tank, a stirring unit arranged in the washing and filtering tank, a drainage system connected with the washing and filtering tank, a vacuumizing system and a backwashing system, the washing filtering tank comprises a closed tank body and a filtering net group arranged in the tank body; the filter screen group comprises a cylindrical filter screen matched in the tank body along the inner peripheral side wall of the tank body, and an arc-shaped filter screen connected to the bottom of the cylindrical filter screen and matched at the bottom of the tank body; an annular interval between the cylindrical filter screen and the inner peripheral side wall of the tank body forms a side drainage cavity, and an interval between the arc-shaped filter screen and the bottom of the tank body forms a bottom drainage cavity. The fly ash washing and filtering integrated equipment integrates mixing, washing and efficient dehydration, and the filter screen group is arranged in the tank body along the side wall and the bottom of the tank body, so that the effective filtering area is greatly increased, dynamic thin-layer filtering is realized, the filter screens are effectively prevented from being blocked, and the dehydration time is remarkably shortened.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, and in particular to an integrated fly ash washing and filtration device and a fly ash washing and filtration method. Background Technology

[0002] Industrial solid wastes such as fly ash often require washing to remove soluble salts and heavy metals. In traditional three-stage countercurrent fly ash washing processes, washing and dewatering are usually completed in different equipment, resulting in problems such as long process flow, large equipment footprint, easy clogging of filter screens by fine particles, low dewatering efficiency, and heavy maintenance workload. Especially for fly ash with a wide particle size distribution and small average particle size (e.g., 1-100 microns), conventional static filtration easily forms a dense filter cake layer on the filter screen, leading to a sharp increase in filtration resistance, excessively long dewatering time, or even failure to proceed normally.

[0003] In the existing technology, an integrated design scheme is attempted to set a fixed filter plate at the bottom of the mixing tank, but it generally has the following defects: (1) The filtration area is limited and the dewatering speed is slow; (2) The flat bottom filter plate and the tank wall are prone to forming dead corners for mixing and drainage, which affects the mixing effect and the thoroughness of dewatering; (3) The filter cake is statically compacted on the filter plate, making subsequent cleaning or unloading difficult; (4) In the single vacuum dewatering mode, a large amount of free water cannot be quickly removed in the early stage, resulting in low efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an integrated fly ash washing and filtration device and a fly ash washing and filtration method.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to provide an integrated fly ash washing and filtration equipment, including a washing and filtration tank, a stirring device for stirring in the washing and filtration tank, a drainage system connected to the washing and filtration tank, a vacuum system and a backwashing system; The water washing filter tank includes a sealed tank body and a filter screen assembly disposed within the tank body; the top of the tank body is provided with a fly ash inlet, and the bottom of the tank body is arc-shaped and provided with a discharge outlet; the filter screen assembly includes a cylindrical filter screen that fits into the tank body along the inner circumferential side wall of the tank body, and an arc-shaped filter screen that is connected to the bottom of the cylindrical filter screen and fits into the bottom of the tank body. The annular gap between the cylindrical filter screen and the inner circumferential side wall of the tank forms a side drainage cavity, and the gap between the arc-shaped filter screen and the bottom of the tank forms a bottom drainage cavity.

[0006] Preferably, the stirring device includes a stirrer disposed inside the water washing filter tank and a drive mechanism connected to the stirrer; the drive mechanism is located outside the water washing filter tank and drives the stirrer to rotate and move up and down relative to the water washing filter tank.

[0007] Preferably, the drainage system includes a drainage pipe connecting the side drainage chamber and a drainage valve disposed on the drainage pipe; The vacuum system includes a vacuum pump, a vacuum pipeline connected between the vacuum pump and the bottom of the tank, a vacuum valve installed on the vacuum pipeline, and a vacuum buffer tank connected to the vacuum pipeline; the vacuum pipeline is connected to the bottom drain chamber.

[0008] Preferably, the vacuum system further includes a gas-water separator connected to the vacuum pump; the outlet of the gas-water separator is connected to the vacuum buffer tank via a return water pipe.

[0009] Preferably, the backwashing system includes a backwashing pump, a backwashing pipeline connected between the backwashing pump and the tank, and a backwashing valve disposed on the backwashing pipeline.

[0010] Preferably, the side drainage cavity is provided with at least one partition, which divides the side drainage cavity into at least two drainage sub-cavities arranged vertically.

[0011] The present invention also provides a fly ash water washing and filtration method, which uses the integrated fly ash water washing and filtration equipment described in any of the above-mentioned embodiments, and the fly ash water washing and filtration method includes the following steps: S1. Send fly ash and water into the water washing filter tank respectively, and start the stirring device to mix fly ash and water at high speed; S2. Reduce the speed of the stirring device, open the drainage system, and use gravity to drain the washing liquid in the water washing filter tank. S3. Close the drainage system and start the vacuum system to perform vacuum dehydration on the water washing filter tank. The dehydrated fly ash forms a filter cake. S4. Turn off the vacuum system, turn on the backwashing system, inject high-pressure water into the water washing filter tank, turn on the stirring device, clean the filter screen group in the water washing filter tank and break the filter cake into slurry, and discharge the slurry.

[0012] Preferably, in step S3, the agitator of the stirring device rotates at a low speed of 5 rpm to 15 rpm and moves up and down along the water washing filter tank to scrape the filter screen assembly inside the water washing filter tank.

[0013] Preferably, in step S1, the stirring device rotates at a speed of 60 rpm to 120 rpm; in step S2, the stirring device rotates at a speed of 5 rpm to 10 rpm.

[0014] Preferably, in step S3, the vacuum pump of the vacuum system provides a vacuum level of -0.08 MPa to -0.095 MPa.

[0015] Preferably, in step S4, the pressure of the high-pressure water provided by the backwashing system is 0.2 MPa to 0.5 MPa.

[0016] Preferably, in step S4, when the water level exceeds the height of the filter cake, the agitator of the stirring device is activated, causing it to gradually move downwards and break the filter cake into slurry, which is then discharged.

[0017] The beneficial effects of this invention are: it integrates mixing, washing and efficient dehydration, and the filter screen is set along the side wall and bottom of the tank, which greatly increases the effective filtration area, realizes dynamic thin-layer filtration, effectively prevents filter screen clogging, significantly shortens the dehydration time, and facilitates the crushing and re-slurrying of the filter cake. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of an integrated fly ash washing and filtration device according to an embodiment of the present invention. Detailed Implementation

[0019] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] like Figure 1 As shown, an embodiment of the fly ash water washing and filtration integrated equipment of the present invention includes a water washing filter tank 10, a stirring device 20, a drainage system 30, a vacuum system 40 and a backwashing system 50.

[0021] The water washing filter tank 10 is used for washing and dewatering fly ash. The stirring device 20 is used to mix and stir the fly ash and water within the water washing filter tank 10. The drainage system 30 is used to discharge the washing liquid formed after washing the fly ash. The vacuum system 40 is used for vacuum dewatering of the water washing filter tank 10. The backwashing system 50 is used to supply backwash water into the water washing filter tank 10 to facilitate the drainage of fly ash from the tank and can also be used for rinsing the tank after use.

[0022] Specifically, the water washing filter tank 10 includes a sealed tank body 11 and a filter screen assembly 12 disposed within the tank body 11. The tank body 11 has a cylindrical structure, preferably a circular shape, and the bottom of the tank body 11 is arc-shaped to avoid forming dead corners. The top of the tank body 11 is provided with a fly ash inlet 101, through which the fly ash to be treated is fed into the tank body 11. The bottom of the tank body 11 is provided with a discharge port 102 for discharging the treated fly ash, etc. The discharge port 102 is provided with a discharge valve 103 to control the opening and closing of the discharge port 102.

[0023] The bottom of the tank 11 is specifically an outwardly convex arc shape, which may include a hemispherical or arched shape.

[0024] As needed, the tank body 11 is also provided with a manhole 104 for convenient maintenance, etc. The manhole 104 is preferably located at the top of the tank body 11.

[0025] The filter assembly 12 is fitted inside the tank 11, corresponding to the shape of the tank 11. The filter assembly 12 may further include a cylindrical filter 121 and an arc-shaped filter 122 connected to the bottom of the cylindrical filter 121. The cylindrical filter 121 is fitted inside the tank 11 along the inner peripheral sidewall of the tank 11, and an annular gap is left between it and the inner peripheral sidewall of the tank 11, which forms a side drainage cavity 110. The arc-shaped filter 122 is fitted to the bottom of the tank 11, and a gap is left between it and the bottom of the tank 11, which forms a bottom drainage cavity 120.

[0026] The top of the cylindrical filter screen 121 is open, allowing fly ash to enter the tank 11 from the fly ash inlet 101 at the top of the tank 11 and fall into the filter screen assembly 12. The mesh sizes of the cylindrical filter screen 121 and the arc-shaped filter screen 122 are 5μm to 30μm, respectively.

[0027] Furthermore, at least one set of connecting components 61 is provided between the tank body 11 and the filter assembly 12, and the filter assembly 12 is supported and positioned within the tank body 11 by the connecting components 61. Each connecting component 61 includes at least one connector, and two or more connectors can be arranged at intervals along the inner circumference of the tank body 11. In embodiments where multiple sets of connecting components 61 are provided between the tank body 11 and the filter assembly 12, the multiple sets of connecting components 61 are arranged at intervals along the axial direction of the tank body 11; in two axially adjacent sets of connecting components 61, the connectors of the two sets of connecting components 61 can be staggered in the circumferential direction, forming a dispersed arrangement relative to the filter assembly 12, making the filter assembly 12 more stable within the tank body 11. Figure 1 In the embodiment shown, three sets of connecting components 61 are also provided between the tank 11 and the filter screen group 12. One connecting component 61 is located at the connection between the side drainage chamber 110 and the bottom drainage chamber 120, and the other two sets of connecting components 61 are located inside the side drainage chamber.

[0028] The connecting parts can be bolts, connecting rods, or connecting supports, etc.

[0029] In some embodiments, at least one partition may be provided between the tank 11 and the filter assembly 12. The partition serves to support and position the filter assembly 12 while dividing the side drainage chamber 110 into at least two drainage chambers arranged vertically.

[0030] A stirring device 20 extends into the water washing filter tank 10 from the top and is used to stir and mix the fly ash and water inside the water washing filter tank 10. Specifically, the stirring device 20 may include a stirrer 21 and a drive mechanism 22. The stirrer 21 is located inside the water washing filter tank 10, and the drive mechanism 22 is located outside the water washing filter tank 10 and connected to the stirrer 21, driving the stirrer 21 to rotate and move up and down.

[0031] exist Figure 1 In the illustrated embodiment, the stirrer 21 includes a stirring shaft 221 and a scraper stirring body 222 connected to the end of the stirring shaft 221. Inside the water washing filter tank 10, the stirring shaft 221 extends axially along the water washing filter tank 10, and the scraper stirring body 222 is located at the end of the stirring shaft 221 facing the bottom of the water washing filter tank 10.

[0032] The scraper stirring body 222 is preferably an anchor structure that matches the inner wall and bottom contour of the tank 11, and its edge is provided with a flexible scraper that can scrape the filter screen group 12.

[0033] The drive mechanism 22 includes a motor, the motor shaft is connected to the stirring shaft 221 of the stirrer 21, and drives the stirring shaft 221 to rotate so as to realize the rotation of the entire stirrer 21.

[0034] The motor is further selected as a lifting motor, which is also used to drive the agitator 21 to move up and down within the water washing filter tank 10, thereby achieving lifting and lowering motion relative to the water washing filter tank 10. Alternatively, the drive mechanism 22 may also include a lifting assembly for driving the agitator to move up and down.

[0035] The drainage system 30 is connected to the water washing filter tank 10 and communicates with the interior of the water washing filter tank 10. The drainage system 30 may further include a drainage pipe 31 communicating with the side drainage chamber 110 and a drainage valve 32 provided on the drainage pipe 31. The washing liquid and other substances in the water washing filter tank 10 can be discharged through the drainage pipe 31 under the action of gravity.

[0036] In some embodiments, reference Figure 1 The drainage pipe 31 of the drainage system 30 has multiple connecting branches 33, which are connected to different heights of the tank 11 and communicate with the side drainage chamber 110. The washing liquid and other liquids at different heights in the washing filter tank 10 can be discharged to the outside of the tank through the corresponding connecting branches 33, realizing layered drainage and flexibly controlling the dehydration process according to the characteristics of the washing liquid.

[0037] Each connecting branch 33 is equipped with a drain valve 32, which controls the opening and closing of the corresponding connecting branch 33. In an embodiment where the side drainage chamber 110 has a drainage sub-chamber, the connecting branch 33 is connected to the drainage sub-chamber at the corresponding height to achieve layered drainage.

[0038] A vacuum system 40 is connected to and communicates with the interior of the water washing filter tank 10 to perform vacuum dehydration. Specifically, the vacuum system 40 may include a vacuum pump 41, a vacuum pipeline 42, a vacuum valve 43, and a vacuum buffer tank 44. The vacuum pipeline 42 connects the vacuum pump 41 and the bottom of the tank 11, communicating with the bottom drain chamber 120. The vacuum valve 43 and the vacuum buffer tank 44 are respectively connected to the vacuum pipeline 42. The vacuum valve 43 is located between the tank 11 and the vacuum buffer tank 44 and is used to control the opening and closing of the vacuum pipeline 42. The vacuum buffer tank 44 is located before the inlet of the vacuum pump 41, serving a pressure stabilizing function and preventing liquids, fly ash, etc., extracted from the tank 11 from entering the vacuum pump 41.

[0039] Furthermore, the vacuum system 40 may also include a gas-liquid separator 45, which is connected to the outlet of the vacuum pump 41. The outlet of the gas-liquid separator 45 is connected to the vacuum buffer tank 44 through a return water pipe 46, and the separated liquid can enter the vacuum buffer tank 44 through the return water pipe 46.

[0040] The backwashing system 50 is connected to the water washing filter tank 10 and communicates with the inside of the water washing filter tank 10. It is used to deliver backwash water into the water washing filter tank 10 for rinsing and other treatments.

[0041] The backwashing system 50 may specifically include a backwashing pump 51, a backwashing pipeline 52, and a backwashing valve 53. The backwashing pipeline 52 connects the backwashing pump 51 and the tank 11, communicating with the interior of the water-washing filter tank 10, specifically connecting the side drain chamber 110 and the bottom drain chamber 120. The backwashing pump 51 provides backwashing water (high-pressure water), which is delivered to the tank 11 through the backwashing pipeline 52. The backwashing valve 53 is installed on the backwashing pipeline 52 and is used to control the on / off state of the backwashing pipeline 52.

[0042] In some embodiments, reference Figure 1 The backwashing system 50 has a backwashing pipeline 52 with multiple backwashing branches 54, which are connected to different heights of the tank 11. The backwashing branch 54 connected to the outer wall of the tank 11 is connected to the side drain chamber 110, and the backwashing branch 54 connected to the bottom of the tank 11 is connected to the bottom drain chamber 120. Each backwashing branch 54 is equipped with a backwashing valve 53, which controls the on / off state of the corresponding backwashing branch 54.

[0043] The integrated fly ash washing and filtration equipment of the present invention is used for washing, filtering, and dewatering fly ash. (See reference...) Figure 1 The fly ash washing and filtration method implemented by the integrated fly ash washing and filtration equipment may include the following steps: S1. Water washing and mixing: Fly ash and water are fed into the water washing filter tank 10 respectively, and the stirring device 20 is started to mix the fly ash and water at a speed of 60 rpm to 120 rpm.

[0044] Fly ash is fed into tank 11 through fly ash inlet 101 at the top of tank 11. Water can also be fed into tank 11 through fly ash inlet 101 or through backwashing system 50.

[0045] S2. Gravity drainage: Reduce the speed of the stirring device 20 to 5 rpm to 10 rpm; open the drainage system 30 and use gravity to drain most of the washing liquid in the water washing filter tank 10.

[0046] The washing solution is a waste liquid formed after washing the fly ash with a mixture of water and fly ash. The fly ash is trapped in the tank 11 by the filter screen group 12.

[0047] S3. Dynamic vacuum dewatering: Close the drainage system 30, start the vacuum system 40, and perform vacuum dewatering on the water washing filter tank 10. The dewatered fly ash forms a filter cake.

[0048] The vacuum pump in the vacuum system 40 provides a vacuum level of -0.08 MPa to -0.095 MPa.

[0049] While starting the vacuum system 40, start the stirring device 20, control the stirrer of the stirring device 20 to rotate at a low speed of 5 rpm to 15 rpm and move up and down along the water washing filter tank 10 to scrape the filter screen group 12 inside the water washing filter tank 10, so as to scrape the fly ash remaining on the filter screen group 12 down to the bottom of the water washing filter tank 10.

[0050] S4. Filter cake treatment and filter screen cleaning: Close the vacuum system 40, open the backwashing system 50, inject high-pressure water (also backwash water) into the water washing filter tank 10, turn on the stirring device 20, clean the filter screen group 12 in the water washing filter tank 10 and break the filter cake into slurry, and discharge the slurry.

[0051] The backwashing system 50 provides high-pressure water at a pressure of 0.2 MPa to 0.5 MPa.

[0052] After the stirring device 20 is started, the agitator 21 stirs the high-pressure water in the water washing filter tank 10, and at the same time, it can backwash and mechanically scrape the filter screen assembly 12 to restore the permeability of the filter screen. When the water level exceeds the height of the filter cake, the agitator 21 of the stirring device 20 is started, which moves downwards and drives the scraper agitator body 222 to move downwards and break the filter cake into slurry. Finally, the slurry is discharged through the discharge port 102 and discharge valve 103 at the bottom of the water washing filter tank 10.

[0053] In summary, this invention utilizes a combination of cylindrical and bottom-mounted arc-shaped filter screens to increase the filtration area, making the effective filtration area several times larger than that of a traditional single bottom filter, thus laying the foundation for rapid dewatering. It also improves the flow field within the tank and reduces dead zones. The composite process of gravity-fed liquid drainage combined with dynamic thin-layer vacuum dewatering avoids the inefficient initial stage of a large amount of free water flowing through the vacuum system. Furthermore, the scraper of the agitator continuously breaks down the filter cake during dewatering, maintaining a consistently high filtration flux and reducing the total dewatering time from several hours in traditional static filtration to less than 30 minutes. The dynamic thin-layer filtration principle fundamentally prevents filter cake compaction and clogging. Combined with high-pressure water backwashing and mechanical scraping, the filter screen regeneration effect is excellent, and the equipment operates stably. A single tank completes all functions of washing, dewatering, filter cake breaking, and filter screen cleaning, offering high integration and flexibility while saving space and investment.

[0054] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An integrated fly ash washing and filtration device, characterized in that, It includes a water washing filter tank, a stirring device for stirring within the water washing filter tank, a drainage system connected to the water washing filter tank, a vacuum system, and a backwashing system; The water washing filter tank includes a sealed tank body and a filter screen assembly disposed within the tank body; the top of the tank body is provided with a fly ash inlet, and the bottom of the tank body is arc-shaped and provided with a discharge outlet; the filter screen assembly includes a cylindrical filter screen that fits into the tank body along the inner circumferential side wall of the tank body, and an arc-shaped filter screen that is connected to the bottom of the cylindrical filter screen and fits into the bottom of the tank body. The annular gap between the cylindrical filter screen and the inner circumferential side wall of the tank forms a side drainage cavity, and the gap between the arc-shaped filter screen and the bottom of the tank forms a bottom drainage cavity.

2. The integrated fly ash washing and filtration equipment according to claim 1, characterized in that, The stirring device includes a stirrer disposed inside the water washing filter tank and a drive mechanism connected to the stirrer; the drive mechanism is located outside the water washing filter tank and drives the stirrer to rotate and move up and down relative to the water washing filter tank.

3. The integrated fly ash washing and filtration equipment according to claim 1, characterized in that, The drainage system includes a drainage pipe that connects to the side drainage chamber and a drainage valve installed on the drainage pipe; The vacuum system includes a vacuum pump, a vacuum pipeline connected between the vacuum pump and the bottom of the tank, a vacuum valve installed on the vacuum pipeline, and a vacuum buffer tank connected to the vacuum pipeline; the vacuum pipeline is connected to the bottom drain chamber.

4. The integrated fly ash washing and filtration equipment according to claim 3, characterized in that, The vacuum system also includes a gas-water separator connected to the vacuum pump; the outlet of the gas-water separator is connected to the vacuum buffer tank via a return water pipe.

5. The integrated fly ash washing and filtration equipment according to claim 1, characterized in that, The backwashing system includes a backwashing pump, a backwashing pipeline connected between the backwashing pump and the tank, and a backwashing valve installed on the backwashing pipeline.

6. The integrated fly ash washing and filtration equipment according to any one of claims 1-5, characterized in that, At least one connecting assembly is provided between the tank body and the filter assembly, and the filter assembly is supported and positioned within the tank body via the connecting assembly; and / or The side drainage cavity is provided with at least one partition, which divides the side drainage cavity into at least two drainage sub-cavities arranged vertically.

7. A method for filtering fly ash by washing, characterized in that, The fly ash water washing and filtration integrated equipment according to any one of claims 1-6, the fly ash water washing and filtration method includes the following steps: S1. Send fly ash and water into the water washing filter tank respectively, and start the stirring device to mix fly ash and water at high speed; S2. Reduce the speed of the stirring device, open the drainage system, and use gravity to drain the washing liquid in the water washing filter tank. S3. Close the drainage system and start the vacuum system to perform vacuum dehydration on the water washing filter tank. The dehydrated fly ash forms a filter cake. S4. Turn off the vacuum system, turn on the backwashing system, inject high-pressure water into the water washing filter tank, turn on the stirring device, clean the filter screen group in the water washing filter tank and break the filter cake into slurry, and discharge the slurry.

8. The fly ash washing and filtration method according to claim 7, characterized in that, In step S3, the agitator of the stirring device rotates at a low speed of 5 rpm to 15 rpm and moves up and down along the water washing filter tank to scrape the filter screen assembly inside the water washing filter tank.

9. The fly ash washing and filtration method according to claim 7, characterized in that, In step S1, the stirring device rotates at a speed of 60 rpm to 120 rpm; in step S2, the stirring device rotates at a speed of 5 rpm to 10 rpm.

10. The fly ash washing and filtration method according to claim 7, characterized in that, In step S3, the vacuum pump of the vacuum system provides a vacuum level of -0.08 MPa to -0.095 MPa; In step S4, the pressure of the high-pressure water provided by the backwashing system is 0.2 MPa to 0.5 MPa; In step S4, when the water level exceeds the height of the filter cake, the agitator of the stirring device is started, causing it to move downwards gradually and break the filter cake into slurry, which is then discharged.

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