A coal upgrading device

Abstract

The utility model relates to coal upgrading technical field especially relates to a kind of fine coal upgrading device to solve the problem that the spiral separator and arc screen cannot work cooperatively due to the different concentration of feed material in prior art and affect the quality of commercial coal.The outlet of hydrocyclone is communicated with the feed inlet of spiral separator, and the hydrocyclone is used to deliver coarse slime to the spiral separator.The fixed screen is arranged in the concentrate collection tank of spiral separator, the feed end of fixed screen is connected with the concentrate discharge end of spiral separator, and the discharge end of fixed screen is communicated with the feed inlet of arc screen.The discharge end of arc screen is communicated with the feed inlet of centrifuge, and the arc screen is used to deeply dewater the spiral fine coal that flows through arc screen for pre-dewatering.The fine coal upgrading device is used in fine coal production.

Description

Technical Field

[0001] This utility model relates to the field of coal upgrading technology, and in particular to a refined coal upgrading device. Background Technology

[0002] In coal washing and beneficiation, spiral separators are widely used as sorting equipment for coarse coal slime, while arc screens are widely used as dewatering equipment. However, many coal plants commonly experience poor water removal efficiency with arc screens and unsatisfactory sorting performance with spiral separators. Analysis revealed that the problem stems from the conflicting requirements of spiral separators and arc screens regarding feed concentration. Spiral separators require lower concentrations to ensure effective sorting, while arc screens require higher concentrations to improve dewatering efficiency.

[0003] Currently, the feed concentration is adjusted by regulating the underflow of the hydrocyclone, but it is difficult to simultaneously meet the optimal operating conditions of both spiral separators and arc screens. This results in decreased separation accuracy of the spiral separator, loss of clean coal, excessive product moisture, and insufficient calorific value, which seriously affects the quality of commercial coal.

[0004] Therefore, how to solve the problem that the spiral separator and the arc screen cannot work together due to different feed concentrations in the existing technology, thus affecting the quality of commercial coal, is one of the important problems that urgently need to be solved in this field. Utility Model Content

[0005] In view of this, the present invention provides a refined coal upgrading device to solve the problem in the prior art where the spiral separator and the arc screen cannot work together due to different feed concentrations, thus affecting the quality of commercial coal.

[0006] According to one aspect of the present invention, a fine coal upgrading device is provided, which includes a hydraulic classifier hydrocyclone, a spiral separator, a fixed screen, an arc screen and a centrifuge. The outlet of the hydraulic classifier hydrocyclone is connected to the feed inlet of the spiral separator, and the hydraulic classifier hydrocyclone is used to convey coarse coal slime to the spiral separator. The fixed screen is installed in the concentrate collection tank of the spiral separator. The feed end of the fixed screen is connected to the concentrate discharge end of the spiral separator, and the discharge end of the fixed screen is connected to the feed inlet of the arc screen. The discharge end of the arc screen is connected to the feed inlet of the centrifuge. The arc screen is used to perform deep dewatering on the spiral clean coal that has passed through the arc screen for pre-dewatering.

[0007] According to one aspect of the coal upgrading device of this utility model, the fixed screen is a full-width inclined screen plate; The inclined direction of the fixed screen is the same as the flow direction of the coarse coal slime on the fixed screen, and the radial dimension of the fixed screen is adapted to the radial dimension of the concentrate collection tank, so as to realize the dewatering of the coarse coal slime.

[0008] According to one aspect of the present invention, the inclined angle of the fixed screen is 3°-15°, which is used to extend the dewatering time of the coarse coal slime on the screen plate while ensuring that the coarse coal slime is transported smoothly without stagnation.

[0009] According to one aspect of the present invention, the coal upgrading device further includes a vibration structure disposed on an arc screen, the vibration structure being used to generate vibration to clear coal slime particles clogging the screen holes of the arc screen.

[0010] According to one aspect of the present invention, the coal upgrading device further includes a control component, the excitation structure is electrically connected to the control component, and the control component is used to control the intermittent start and stop of the excitation structure.

[0011] According to one aspect of the present invention, in a coal upgrading device, a vibration structure is detachably installed on the outside of the screen frame of an arc screen, and the vibration direction of the vibration structure is perpendicular to the screen surface of the arc screen.

[0012] According to one aspect of the present invention, the coal upgrading device further includes a feed baffle and an adjustment mechanism. The feed baffle is located at the feed end of the arc screen. The feed baffle is connected to the frame of the arc screen through the adjustment mechanism. The adjustment mechanism is used to adjust the inclination angle of the feed baffle. The feed baffle is used to change the drop position of the coarse coal slime on the screen surface of the arc screen, so as to prolong the movement time of the coarse coal slime on the screen surface.

[0013] According to one aspect of the present invention, the refined coal upgrading device further includes a preset screen surface, which is located at the feed inlet of the arc screen. The radial dimension of the preset screen surface is 200mm, and the upper surface of the preset screen surface is flush with the screen surface at the feed inlet of the arc screen, for auxiliary pre-dehydration of the fed spiral refined coal.

[0014] According to one aspect of the coal upgrading device of this utility model, the screen aperture of the fixed screen is 0.1mm-0.15mm; the thickness of the screen plate of the fixed screen is 8mm-12mm; and the screen plate of the fixed screen is a stainless steel screen plate.

[0015] According to one aspect of the present invention, the refined coal upgrading device further includes a regulating flushing valve, which is located at the underflow outlet of the hydraulic classifier. The regulating flushing valve is used to adjust the concentration of coarse coal slime conveyed to the spiral separator.

[0016] The above-mentioned technical solutions adopted in this embodiment of the utility model can achieve the following beneficial effects: In the above-mentioned clean coal upgrading device, the hydrocyclone can separate the feed coal slurry into a finer overflow and a coarser underflow. By setting it before the spiral separator, it ensures that the material entering the spiral separator is coarse coal slurry with a relatively stable particle size distribution and suitable concentration. This eliminates the direct impact of large fluctuations in the concentration of raw coal slurry on the spiral separator. It provides the spiral separator with optimal and stable working conditions, allowing it to always operate within the high-efficiency separation range, thereby significantly improving the recovery rate and separation accuracy of clean coal products. Based on this, the fixed screen is directly set in the concentrate collection tank of the spiral separator, connecting the concentrate discharge end with the arc screen. The concentrate discharged from the spiral separator is a slurry material, and the concentration may still be instantaneously uneven. With the fixed screen placed in the collection tank, the material falls onto the screen first, which can harmonize the fluctuations in instantaneous flow rate and concentration, and avoid a high-concentration slurry directly impacting the arc screen. The fixed screen has a larger slit, which can immediately remove a portion of the free water from the concentrate slurry. This not only reduces the processing load of the subsequent arc screen, but also, after adjustment by the fixed screen, delivers the material to the arc screen with a more uniform and stable flow rate and a higher solids concentration. This perfectly solves the problem of low dewatering efficiency of the arc screen due to unstable feed. Furthermore, the discharge end of the arc screen is connected to the centrifuge inlet for pre-dewatering. As the core dewatering equipment, the arc screen is responsible for removing most of the surface water. Due to the stable feed from the fixed screen, the arc screen can achieve optimal dewatering results. After dewatering by the arc screen, the material changes from a slurry to a loose, moist filter cake, with a significantly increased solids concentration. Such material is very suitable for deep dewatering in a centrifuge. The centrifuge does not need to handle large amounts of water, resulting in lower energy consumption, higher processing capacity, and lower and more stable moisture content in the final product. This effectively solves the problem in existing technologies where the spiral separator and arc screen cannot work together due to different feed concentrations, affecting the quality of marketable coal. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a refined coal upgrading device provided as an example of this utility model; Figure 2 This is an enlarged schematic diagram of the structure of part A, provided as an example of this utility model; Figure 3 This is a three-dimensional structural diagram of part A, which is provided as an example of this utility model.

[0019] Figure label: 101-Hydraulic classifier hydrocyclone, 102-Spiral separator, 103-Arc screen, 104-Centrifuge, 105-Vibration structure, 201-Concentrate collection tank, 202-Fixed screen. Detailed Implementation

[0020] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0021] It should be understood that the steps described in the method embodiments of this utility model may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this utility model is not limited in this respect.

[0022] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this utility model are only used to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0023] It should be noted that the terms "a" and "a plurality of" used in this utility model are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0024] The names of the messages or information exchanged between the multiple devices in this embodiment of the invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0025] In coal washing and beneficiation, spiral separators are widely used as sorting equipment for coarse coal slime, while arc screens are widely used as dewatering equipment. However, many coal plants commonly experience poor water removal efficiency with arc screens and unsatisfactory sorting performance with spiral separators. Analysis revealed that the problem stems from the conflicting requirements of spiral separators and arc screens regarding feed concentration. Spiral separators require lower concentrations to ensure effective sorting, while arc screens require higher concentrations to improve dewatering efficiency.

[0026] Currently, the feed concentration is adjusted by regulating the underflow of the hydrocyclone, but it is difficult to simultaneously meet the optimal operating conditions of both spiral separators and arc screens. This results in decreased separation accuracy of the spiral separator, loss of clean coal, excessive product moisture, and insufficient calorific value, which seriously affects the quality of commercial coal.

[0027] To address the aforementioned problems, an exemplary embodiment of this utility model provides a refined coal upgrading device to solve the problem in the prior art where the spiral separator and the arc screen cannot work together due to different feed concentrations, thus affecting the quality of commercial coal.

[0028] The following will describe in detail, with reference to the accompanying drawings, a refined coal upgrading device according to an embodiment of the present utility model.

[0029] Figure 1 This is a schematic diagram of the structure of a clean coal upgrading device provided as an example of the present invention, such as... Figure 1 As shown, the outlet of the hydrocyclone 101 is connected to the inlet of the spiral separator 102, and the hydrocyclone 101 is used to convey coarse coal slime to the spiral separator 102. A fixed screen 202 is installed inside the concentrate collection tank 201 of the spiral separator 102. The inlet end of the fixed screen 202 is connected to the concentrate outlet end of the spiral separator 102, and the outlet end of the fixed screen 202 is connected to the inlet of the arc screen 103. The outlet end of the arc screen 103 is connected to the inlet of the centrifuge 104, and the arc screen 103 is used for deep dewatering of the spiral clean coal that has passed through the arc screen 103 for pre-dewatering.

[0030] In practical applications, such as Figure 1As shown, the hydrocyclone can separate the feed coal slurry into a finer overflow and a coarser underflow. By placing it before the spiral separator 102, it ensures that the material entering the spiral separator 102 is coarse coal slurry with a relatively stable particle size distribution and suitable concentration. This eliminates the direct impact of large fluctuations in the concentration of the raw coal slurry on the spiral separator 102. It provides the spiral separator 102 with optimal and stable working conditions, allowing it to always operate within the high-efficiency separation range, thereby significantly improving the recovery rate and separation accuracy of the clean coal product. Based on this, the fixed screen 202 is directly installed in the concentrate collection tank 201 of the spiral separator 102, connecting the concentrate discharge end to the arc screen 103. The concentrate discharged from the spiral separator 102 is a slurry material, and its concentration may still be momentarily uneven. With the fixed screen 202 placed in the collection tank, the material falls onto the screen first, which can harmonize the fluctuations in instantaneous flow rate and concentration, and prevent streams of high-concentration slurry from directly impacting the arc screen 103. The fixed screen 202 has a larger screen opening, which can immediately remove a portion of the free water from the concentrate slurry. This not only reduces the processing load on the subsequent arc screen 103, but also, after adjustment by the fixed screen 202, delivers the material to the arc screen 103 with a more uniform and stable flow rate and a higher solids concentration. This perfectly solves the problem of low dewatering efficiency of the arc screen 103 due to unstable feed. Furthermore, the discharge end of the arc screen 103 is connected to the inlet of the centrifuge 104, responsible for pre-dewatering. As the core dewatering device, the arc screen 103 is responsible for removing most of the surface water. Due to the stable feeding from the fixed screen 202, the arc screen 103 can achieve optimal dewatering results. After dewatering by the arc screen 103, the material changes from a slurry to a loose, moist filter cake, with a significantly increased solids concentration. Such material is very suitable for deep dewatering by the centrifuge 104. The centrifuge 104 does not require the processing of large amounts of water, resulting in lower energy consumption, stronger processing capacity, and lower and more stable moisture content in the final product. This effectively solves the problem in the existing technology that the spiral separator 102 and the arc screen 103 cannot work together due to different feed concentrations, thus affecting the quality of commercial coal.

[0031] For example, Figure 2 This is an enlarged schematic diagram of the structure of part A, which is provided as an example of this utility model. Figure 3 This is a three-dimensional structural diagram of part A, provided as an example of the present utility model. Figures 2-3 As shown, the fixed screen 202 is a full-width inclined screen plate. The inclination direction of the fixed screen 202 is the same as the flow direction of the coarse coal slime in the fixed screen 202, and the radial dimension of the fixed screen 202 is adapted to the radial dimension of the concentrate collection tank 201, so as to realize the coarse coal slime covering and dewatering.

[0032] In practical applications, such as Figures 2-3As shown, the concentrate from the spiral separator 102 enters the concentrate collection trough 201 through the concentrate discharge end. Since the radial dimensions of the fixed screen 202 and the collection trough are perfectly matched, it can be understood that the radial dimension of the fixed screen 202 is actually the width of the screen plate, and the radial dimension of the collection trough is actually the width of the collection trough. Furthermore, the fixed screen 202 is a full-width inclined screen plate, ensuring that the material falls evenly across the entire cross-section of the collection trough onto the screen plate. This avoids the problem of material accumulation in the middle and empty edges of traditional narrow-width screen plates, thus improving the utilization rate of the screen surface. Based on this, the fixed screen 202 adopts an inclined screen plate design, and the inclination direction is completely in the same direction as the natural flow direction of the coarse coal slime. This can be understood as the downslope direction of the screen plate being the same as the material flow direction. The material does not require additional power and flows downwards at a uniform speed along the inclined surface of the screen plate solely by its own gravity. The flow speed can be controlled by the inclination angle of the screen plate. During the material flow process, the material always maintains a full-width uniform distribution without local accumulation or flow interruption, laying the foundation for subsequent synchronous dewatering. Based on this, free water in the material, under the action of gravity, seeps downward through the screen holes of the screen plate and falls into the water collection chamber at the bottom of the concentrate collection tank 201. Coarse coal slime particles are intercepted by the screen plate and continue to flow forward. A small amount of coarse gangue or impurities remaining in the spiral separator 102 cannot pass through the screen holes and will flow along the screen plate with the coarse coal slime, preventing impurities from accumulating on the screen surface and clogging the screen holes. The coarse coal slime that has completed dewatering and impurity removal flows along the inclined screen plate to the discharge end. Because the discharge end of the screen plate is precisely connected to the inlet of the arc screen 103, the material can directly and without retention enter the arc screen 103, avoiding moisture rebound or impurity mixing during the material transfer process, and ensuring the stability of the material entering the subsequent process.

[0033] As can be seen from the above implementation process, if Figures 2-3 As shown, traditional narrow-width screens only cover a portion of the collection trough, causing material to concentrate in the middle, resulting in an excessively thick material layer and insufficient moisture penetration. Full-width screens, however, achieve a thin, uniform distribution of material across the entire cross-section, shortening the moisture penetration path and reducing the range of moisture fluctuations in the discharged material, thus preventing localized wet clumps from entering the arc screen 103. Traditional vibrating screens rely on a vibrating motor for drive, and the vibrating components are prone to wear. The full-width inclined fixed screen 202, however, has no moving parts, relying solely on gravity to drive material flow, eliminating vulnerable parts and reducing maintenance costs. Vibration-free operation reduces resonance effects on surrounding equipment, extending the overall lifespan of the device. Because the screen width is perfectly aligned with the collection trough, material flowing from the trough falls onto the screen, preventing spillage from the edges of traditional screens into the collection trough. The full-width design also prevents material accumulation and clumping at the edges of the collection trough, reducing manual cleaning costs. Furthermore, the uniform flow of material along the screen creates a scouring effect on the screen holes, preventing the problem of fine mud clogging the screen holes caused by static or reverse flow of material in traditional fixed screens 202.

[0034] For example, such as Figures 2-3As shown, the tilt angle of the fixed screen 202 is 3°-15°, which is used to extend the dewatering time of the coarse coal slime on the screen plate while ensuring that the coarse coal slime is transported smoothly without stagnation.

[0035] In practical applications, such as Figures 2-3 As shown, if the tilt angle is less than 3°, the coarse coal slime is not sufficiently subjected to gravity, making it prone to localized accumulation on the screen plate. This results in subsequent coal slime covering the already accumulated slime, reducing the actual permeable area in contact with the screen surface, and making it difficult for moisture inside the accumulated layer to drain through the screen holes. If the angle is greater than 15°, the coal slime slides quickly across the screen surface under gravity, shortening the residence time. Moisture does not have enough time to permeate through the screen holes, leading to an increase in the moisture content of the coal slime after dewatering. An angle range of 3°-15° allows the coarse coal slime to move slowly and in a partially flattened state, avoiding ineffective coverage due to accumulation while ensuring sufficient time for moisture to drain through the screen holes, meeting the moisture requirements for subsequent washing, storage, or transportation. In addition, coarse coal slime often contains fine coal dust and clay impurities. If the tilt angle is inappropriate, too small an angle will cause fine particles to embed into the screen holes when the coal slime is retained. Too large an angle will cause impact friction on the screen holes when the coal slime slides at high speed, squeezing fine particles into the gaps in the screen holes. Gravity can drive the coal slime to move slowly, preventing fine particles from remaining above the screen holes for a long time. Low-speed sliding does not generate strong compression, reducing the probability of fine particles embedding into the sieve holes, ensuring the stability of the water permeability channel, and further improving dewatering efficiency.

[0036] Secondly, the movement of coarse coal slime on the screen plate depends on the component of gravity along the screen surface, G1 = Gsinθ, where θ is the inclination angle. The frictional force between the coal slime and the screen surface is f = μGcosθ, where μ is the coefficient of friction, usually taken as 0.3-0.4. When θ = 3°, sinθ ≈ 0.052, cosθ ≈ 0.998, at this time G1 ≈ 0.052G, f ≈ 0.3 × 0.998G ​​≈ 0.299G. G1 is slightly less than f, but combined with the subsequent thrust of the coarse coal slime, the balance can be broken to achieve slow conveying and avoid stagnation. When θ = 15°, sinθ ≈ 0.259, cosθ ≈ 0.966, at this time G1 ≈ 0.259G, f ≈ 0.3 × 0.966G ≈ 0.290G. G1 is close to f, and the coal slime can maintain a uniform sliding speed, neither causing excessive impact on subsequent equipment due to excessive speed nor causing accumulation at the front end due to excessive speed. When the initial moisture content of the coarse coal slime is high, the coefficient of friction μ between the slime and the screen surface will increase. In this case, the tilt angle can be appropriately increased to counteract the higher friction by increasing the gravitational component G1, thus preventing the sticky slime from remaining. When the initial moisture content of the coarse coal slime is low, the coefficient of friction μ between the slime and the screen surface will decrease. The angle can be adjusted to a smaller value to further remove residual moisture by extending the residence time, eliminating the need for additional dewatering equipment and reducing system energy consumption.

[0037] For example, such as Figure 1As shown, the excitation structure 105 is mounted on the arc-shaped screen 103. The excitation structure 105 is used to generate vibration to clear coal slime particles clogging the screen holes of the arc-shaped screen 103. The excitation structure 105 is electrically connected to a control unit, which is used to control the intermittent start and stop of the excitation structure 105. The excitation structure 105 is detachably mounted on the outside of the screen frame of the arc-shaped screen 103, and the vibration direction of the excitation structure 105 is perpendicular to the screen surface of the arc-shaped screen 103.

[0038] In practical applications, such as Figure 1 As shown, the vibration generated by the excitation structure 105 causes high-frequency vibration of the screen surface of the arc screen 103. This helps to break the adhesion and friction between the coal slime particles and the screen holes, causing the coal slime particles clogging the screen holes to be shaken off, thus keeping the screen holes clear. Based on this, the control unit controls the intermittent start and stop of the excitation structure 105, and the working time of the excitation structure 105 can be flexibly adjusted according to the screen hole clogging situation and the actual needs of the screening operation. During periods when the screen holes are not easily clogged or when the coal slime particle clogging is minor, the excitation structure 105 can be suspended, thereby reducing the energy consumption and wear of the equipment and extending the service life of the excitation structure 105 and the entire arc screen 103. At the same time, intermittent start and stop can also avoid fatigue damage to the screen surface caused by long-term continuous vibration, further improving the reliability of the equipment. Secondly, the excitation structure 105 is detachably installed on the outside of the screen frame of the arc screen 103. This installation method makes the maintenance and replacement of the excitation structure 105 more convenient and quick. When the vibration structure 105 malfunctions or requires maintenance, workers can disassemble it directly from the outside of the screen frame, eliminating the need for extensive disassembly of the entire arc screen 103. This significantly shortens equipment maintenance time and reduces maintenance costs. Furthermore, the vibration direction of the vibration structure 105 is perpendicular to the screen surface of the arc screen 103, allowing it to apply force more directly to the clogging particles within the screen holes. This makes it easier for the clogging particles to be vibrated out of the screen holes, resulting in a more significant cleaning effect compared to other non-perpendicular vibration designs. Simultaneously, the perpendicular vibration direction reduces lateral friction on the screen surface, preventing accelerated wear caused by lateral vibration, thus protecting the screen surface and extending its service life.

[0039] For example, such as Figure 1 As shown, the feed baffle is located at the feed end of the arc screen 103. The feed baffle is connected to the frame of the arc screen 103 through an adjustment mechanism. The adjustment mechanism is used to adjust the inclination angle of the feed baffle. The feed baffle is used to change the drop position of the coarse coal slime on the screen surface of the arc screen 103, so as to prolong the movement time of the coarse coal slime on the screen surface.

[0040] In practical applications, such as Figure 1As shown, the dewatering and desliming effects of the arc screen 103 are directly related to the effective contact time of the coarse coal slime on the screen surface. The longer the contact time, the easier it is for the moisture and medium in the coal slime to separate through the screen holes. If the material drop position is too close to the discharge end of the arc screen 103, the material's movement distance on the screen surface is short and the residence time is insufficient. Moisture or medium is discharged before it can be fully separated, resulting in poor screening effect. By adjusting the inclination angle of the feed baffle to shift the material drop position towards the feed end of the arc screen 103, the movement path and residence time of the material on the screen surface can be extended, allowing more time for moisture or medium to permeate and be discharged through the screen holes, ultimately improving the dewatering and desliming rates of the coarse coal slime. Furthermore, when the coarse coal slime has a fine particle size and high moisture content, the baffle angle can be finely adjusted to place the material drop position slightly further back, preventing material accumulation at the feed end. When the coarse coal slime processing volume increases, the baffle angle can be adjusted to optimize the material distribution, ensuring that the material is evenly spread on the screen surface and preventing a decrease in screening efficiency due to excessive local material thickness. Without the need to replace the baffles or modify the equipment, it can be adapted to different working conditions simply by adjusting the mechanism, which greatly improves the versatility of the arc screen 103 and reduces the equipment downtime for adjustment due to fluctuations in working conditions.

[0041] Furthermore, if the feed baffle angle is fixed and the material drop position is singular, it can easily lead to uneven distribution of coarse coal slime on the screen surface. Material accumulation near the drop point can become too thick, causing screen holes to become clogged, and excessive local pressure can accelerate screen surface wear. Screen areas far from the drop point will remain unloaded, resulting in wasted effective screening area. By adjusting the inclination angle of the feed baffle, the material drop trajectory and initial distribution can be controlled, ensuring that coarse coal slime evenly covers the effective screening area of ​​the screen surface. This avoids localized material overload, reducing the probability of screen hole clogging. It also disperses the force on the screen surface, preventing excessive localized wear, extending the screen surface's service life, and reducing the frequency of screen replacement and maintenance costs. When coarse coal slime is transported from upstream equipment to the arc screen 103, it carries a certain falling speed. If it directly impacts the screen surface, it can cause two problems: high-speed impact can intensify screen surface vibration, which over time can easily cause loosening of the screen frame and screen surface connecting bolts, and even deformation of the screen structure. Material near the impact point is easily compacted, forming a dense layer that hinders moisture penetration and reduces screening efficiency. The feed baffle, through adjustable tilt angle, buffers and guides the falling coarse coal slime. The baffle alters the material's falling direction and speed, allowing it to land on the screen surface with a gentler trajectory, reducing direct impact. This prevents the material from forming a dense layer due to impact, protects the screen frame, connecting components, and other structural parts, reduces equipment failures caused by impact, and extends the overall service life of the arc screen 103.

[0042] For example, a preset screen surface is set at the feed inlet of the arc screen, the radial dimension of the preset screen surface is 200mm, and the upper surface of the preset screen surface is flush with the screen surface of the feed inlet of the arc screen, which is used to assist in the pre-dewatering of the feed spiral coal.

[0043] In practical applications, spiral coking coal typically carries a high level of free moisture when output from the upstream spiral separator. If it directly enters the main screen of the arc screen, a large amount of moisture will mix with the coal particles and flow rapidly. This not only shortens the effective dewatering time of the coal particles on the main screen but may also cause the coal particles to stick to the screen surface and clog the screen holes due to excessive moisture. Spiral coking coal first contacts a pre-designed screen surface. Its flat screen structure allows the coal particles to spread evenly, and the free moisture between the particles can be discharged in advance through the screen holes of the pre-designed screen surface, reducing the moisture content of the material entering the main screen of the arc screen. After pre-dewatering, the wet stickiness of the spiral coking coal is reduced, and its flowability on the main screen of the arc screen is more stable, avoiding material runoff or screen sticking problems caused by excessive moisture. This indirectly extends the effective dewatering time of the coal particles on the main screen surface, ultimately improving the overall dewatering efficiency. Based on this, the output trajectory of the spiral coking coal has a certain spiral inertia. If it directly enters the feed inlet of the arc-shaped screen, material is prone to bias and accumulation, leading to problems such as excessive material thickness and localized empty loads on the main screen surface. Excessive material thickness in some areas will clog the screen holes, reducing screening efficiency, while localized empty loads will waste the effective screen area. The pre-designed screen surface is flush with the feed inlet screen surface. The 200mm radial dimension can buffer the inertial impact force of the spiral coking coal, allowing the material to complete inertial dissipation on the pre-designed screen surface, avoiding direct impact on the main screen surface. The flush screen surface can guide the material to be evenly distributed along the width direction of the arc-shaped screen feed inlet, ensuring that the material entering the main screen surface covers the entire effective screening area, avoiding screen hole clogging and screen surface wear caused by localized overload, and maximizing the screening capacity of the main screen surface.

[0044] Furthermore, fine coal slime particles in high-moisture materials easily adhere to the edges of the main screen openings. Long-term accumulation forms hard scale, which wears down the screen opening edges, causing the openings to enlarge. The inertial impact of the spiral coking coal creates high-frequency impact loads on the main screen surface, potentially leading to fatigue cracks or localized deformation over time, thus shortening its replacement cycle. Pre-removing some free water reduces the amount of fine coal slime adhering to the main screen surface, lowering the probability of hard scale formation and reducing screen wear. It also buffers the inertial impact of the material, preventing the main screen surface from directly bearing impact loads, protecting its structural integrity, and extending its service life. The pre-designed screen surface essentially provides pre-treatment for the main dewatering process of the arc screen. Through a 200mm radial buffer space and a flush screen transition, it ultimately improves the dewatering quality of the spiral coking coal while reducing equipment wear and production fluctuations.

[0045] For example, the screen aperture of the fixed screen is 0.1mm-0.15mm; the thickness of the screen plate of the fixed screen is 8mm-12mm; and the screen plate of the fixed screen is a stainless steel screen plate.

[0046] In practical applications, coarse coal slime treatment typically requires the retention of coarse particles larger than 0.1mm while simultaneously discharging fine mud and water smaller than 0.1mm. A 0.1mm-0.15mm sieve aperture can precisely achieve this goal. For coarse particles larger than 0.1mm, the sieve aperture effectively retains them, preventing leakage and improving the recovery rate of clean coal. For fine mud and free water smaller than 0.1mm, the sieve aperture allows for smooth discharge, reducing the accumulation of fine mud on the screen surface and preventing screen clogging caused by fine mud blocking the sieve apertures, thus ensuring continuous dewatering. If the sieve aperture is too large, some fine mud will mix into the coarse particle product, requiring subsequent desliming equipment. If the sieve aperture is too small, it will hinder water discharge, prolonging dewatering time and reducing production efficiency. Fixed screens must withstand the continuous impact of coarse coal slime during operation. If the screen plate is too thin, it is prone to deformation and cracking due to impact loads, and even premature wear at the edges of the screen apertures. A thickness of 8mm-12mm provides sufficient rigidity to withstand the impact and friction of coarse coal slime over a long period, preventing premature screen failure and extending replacement cycles. However, excessively thick screens increase the channel length, causing fine slime particles to accumulate within the channels and exacerbating clogging. An 8mm-12mm thickness controls the channel length within a reasonable range, ensuring strength while reducing the likelihood of fine slime retention, thus guaranteeing smooth screening and dewatering. Furthermore, stainless steel offers excellent resistance to acids, alkalis, and water vapor corrosion. The surface finish of stainless steel screens is far superior to that of carbon steel, preventing coal slime particles from adhering to the screen surface and screen hole edges, reducing the frequency of screen clogging and minimizing manual cleaning, thereby improving continuous equipment operating efficiency. Even during coal washing, while the fixed screen experiences no vibration, continuous friction and cyclic loads from the material can still lead to fatigue damage to the screen plate. Stainless steel has better toughness than carbon steel, which can better resist fatigue stress caused by cyclic loads, avoid local cracks in the screen plate, further extend its service life, and reduce the overall cost of equipment replacement and maintenance.

[0047] For example, the regulating flush valve is located at the underflow outlet of the hydrocyclone. The regulating flush valve is used to adjust the concentration of coarse coal slime fed to the spiral separator.

[0048] In practical applications, when the underflow concentration of the hydrocyclone is too high, the coal slime becomes a thick paste, unable to flow normally within the spiral separator's trough. Particles cannot achieve stratification through gravity and centrifugal force, easily leading to blockage of the spiral trough and forcing a shutdown for cleaning. Adjusting the flushing valve increases the flushing volume, diluting the concentration to the optimal range, ensuring the coal slime flows uniformly in suspension within the spiral trough, guaranteeing proper stratification and preventing a decrease in clean coal grade or coal carryover in gangue due to excessive concentration. Conversely, when the underflow concentration of the hydrocyclone is too low, the moisture content in the coal slime is too high, causing particles to move too fast within the spiral trough, resulting in insufficient particle residence time and inadequate stratification. Excessive water flow impact can easily disperse the stratified clean coal, causing some fine clean coal particles to be lost with the wastewater. Adjusting the flushing valve reduces the flushing volume, decreasing water introduction and raising the concentration to the optimal range, extending the effective separation time of particles within the spiral trough, ensuring sufficient separation of clean coal and gangue, and improving clean coal recovery rate.

[0049] The above description is merely an illustration of some embodiments of this utility model and the technical principles employed. Those skilled in the art should understand that the scope of this utility model is not limited to the specific combinations of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features of this utility model that have similar functions.

[0050] While specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A coal upgrading device, characterized in that, The refined coal upgrading device includes a hydrocyclone, a spiral separator, a fixed screen, an arc screen, and a centrifuge. The outlet of the hydrocyclone is connected to the inlet of the spiral separator, and the hydrocyclone is used to convey coarse coal slime to the spiral separator. The fixed screen is installed in the concentrate collection tank of the spiral separator. The feed end of the fixed screen is connected to the concentrate discharge end of the spiral separator, and the discharge end of the fixed screen is connected to the feed inlet of the arc screen. The discharge end of the arc screen is connected to the feed inlet of the centrifuge. The arc screen is used to perform deep dewatering on the spiral clean coal that has passed through the arc screen for pre-dewatering.

2. The coal upgrading device according to claim 1, characterized in that, The fixed screen is a full-width inclined screen plate; The inclined direction of the fixed screen is the same as the flow direction of the coarse coal slime on the fixed screen, and the radial dimension of the fixed screen is adapted to the radial dimension of the concentrate collection tank, so as to realize the coarse coal slime covering and dewatering.

3. The coal upgrading device according to claim 1, characterized in that, The fixed screen has an inclination angle of 3°-15°, which is used to extend the dewatering time of the coarse coal slime on the screen plate while ensuring that the coarse coal slime is transported smoothly without stagnation.

4. The coal upgrading device according to claim 1, characterized in that, The refined coal upgrading device also includes a vibration structure, which is installed on the arc screen. The vibration structure is used to generate vibration to clear the coal slime particles clogging the screen holes of the arc screen.

5. The coal upgrading device according to claim 4, characterized in that, The refined coal upgrading device also includes a control component, and the excitation structure is electrically connected to the control component. The control component is used to control the intermittent start and stop of the excitation structure.

6. The coal upgrading device according to claim 4, characterized in that, The excitation structure is detachably installed on the outside of the screen frame of the arc-shaped screen, and the vibration direction of the excitation structure is perpendicular to the screen surface of the arc-shaped screen.

7. The coal upgrading device according to claim 1, characterized in that, The refined coal upgrading device also includes a feed baffle and an adjustment mechanism. The feed baffle is located at the feed end of the arc screen. The feed baffle is connected to the frame of the arc screen through the adjustment mechanism. The adjustment mechanism is used to adjust the inclination angle of the feed baffle. The feed baffle is used to change the drop position of the coarse coal slime on the screen surface of the arc screen, so as to prolong the movement time of the coarse coal slime on the screen surface.

8. The coal upgrading device according to claim 1, characterized in that, The refined coal upgrading device also includes a preset screen surface, which is located at the feed inlet of the arc screen. The radial dimension of the preset screen surface is 200mm, and the upper surface of the preset screen surface is flush with the screen surface at the feed inlet of the arc screen. It is used to assist in the pre-dehydration of the fed spiral refined coal.

9. The coal upgrading device according to claim 1, characterized in that, The screen aperture of the fixed screen is 0.1mm-0.15mm; the thickness of the screen plate of the fixed screen is 8mm-12mm; the screen plate of the fixed screen is a stainless steel screen plate.

10. The coal upgrading device according to claim 1, characterized in that, The refined coal upgrading device also includes a regulating flushing valve, which is located at the underflow outlet of the hydraulic classifier. The regulating flushing valve is used to adjust the concentration of coarse coal slime conveyed to the spiral separator.

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