High-alkali coal pretreatment system

Abstract

The invention relates to a high-alkali coal pretreatment system, which comprises a coal washing system, a solid-liquid separation system and a drying system, and is characterized in that the coal washing system is used for crushing and washing high-alkali coal to obtain coal water slurry; the solid-liquid separation system is connected with the outlet end of the coal washing system, the solid-liquid separation system is used for filtering coal water slurry to obtain coal slime with different particle sizes, the solid-liquid separation system comprises a secondary filter, and the secondary filter is used for filtering coal-containing wastewater filtered by the solid-liquid separation system again to obtain fine coal slime; and the drying system is connected with the outlet end of the solid-liquid separation system and is used for respectively and simultaneously drying the coal slime and the fine coal slime with different particle sizes to obtain coal cinder. When the high-alkali coal pretreatment system is used for treating high-alkali coal, the waste amount of fine-particle-size coal slag in coal slime water can be reduced, so that resources are saved, and the environment is protected.

Description

Technical Field

[0001] This application relates to the technical field of coal-fired power generation, and in particular to a pretreatment system for high-alkali coal. Background Technology

[0002] High-alkali coal is a type of abundant thermal coal characterized by low ash, low sulfur, and low mining costs. However, due to historical factors and geographical environment, the alkali metal content in high-alkali coal is relatively high compared to other coal types, especially the sodium and potassium alkali metal oxide content, which can reach 2-10%. Burning high-alkali coal can cause severe slagging on boiler water-cooled walls and fouling of high-temperature heating surfaces. Sodium in high-alkali coal mainly exists in water-soluble and organic forms. Appropriate constant-temperature water washing conditions can accelerate the removal of water-soluble sodium, and the drying process after water washing further increases its calorific value.

[0003] In related technologies, sodium removal from high-alkali coal mainly relies on water washing. Larger coal particles in the washed coal slurry are then recycled to a drying unit for further drying to obtain coal lumps with higher calorific value. However, in these high-alkali coal washing processes, coal slurry water containing a large amount of fine-grained coal slag is discarded, resulting in resource waste and environmental pollution. Summary of the Invention

[0004] Therefore, it is necessary to provide a high-alkali coal pretreatment system to address the problem of waste of resources and environmental pollution caused by the discarding of fine-particle coal slurry water during the high-alkali coal washing process.

[0005] This application provides a high-alkali coal pretreatment system, comprising:

[0006] The coal washing system is used to crush and wash high-alkali coal to obtain coal-water slurry;

[0007] The solid-liquid separation system is connected to the outlet of the coal washing system. The solid-liquid separation system is used to filter the coal-water slurry to obtain coal slime of different particle sizes. The solid-liquid separation system includes a secondary filter, which is used to filter the coal-containing wastewater after the solid-liquid separation system to obtain fine coal slime.

[0008] The drying system is connected to the outlet of the solid-liquid separation system and is used to simultaneously dry coal slime and fine coal slime of different particle sizes to obtain coal slag.

[0009] In one embodiment, the solid-liquid separation system further includes:

[0010] The main body of the separation container is connected to the outlet end of the coal washing system to obtain coal-water slurry, and the main body of the separation container is provided with a first outlet end;

[0011] Multiple filter screens with different pore sizes are distributed vertically from top to bottom on the inner wall of the separation container body, with the pore size of each filter screen gradually decreasing from top to bottom;

[0012] A wet coal slime collector is connected to the first outlet end to collect coal slime of different particle sizes. The outlet end of the wet coal slime collector is connected to a drying system.

[0013] Multiple coal slime collection components are provided, with each component corresponding to a filter screen. The coal slime collection components are used to periodically transfer the coal slime on each filter screen to the wet coal slime collector.

[0014] In one embodiment, the coal slime collection assembly includes:

[0015] A movable scraper is positioned at one end of the corresponding filter plate.

[0016] The drive unit, connected to the movable scraper, is used to drive the movable scraper to move along the length of the filter screen to transfer the coal slime on the filter screen into the drying system.

[0017] In one embodiment, the separation container body is further provided with a second outlet end, the inlet of the secondary filter is connected to the second outlet end, the outlet end of the secondary filter is connected to the drying system, and the secondary filter is used to perform negative pressure air filtration on the coal-containing wastewater filtered in the separation container body to obtain a filter cake formed by negative pressure of fine coal slime.

[0018] In one embodiment, the high-alkali coal pretreatment system further includes a wastewater circulation system. The inlet of the wastewater circulation system is connected to the outlet of the secondary filter, and the outlet of the wastewater circulation system is connected to the inlet of the coal washing system. The wastewater circulation system is used to purify the wastewater filtered by the secondary filter to obtain clean water, and then transfer the clean water to the coal washing system.

[0019] In one embodiment, the wastewater recycling system includes:

[0020] Wastewater recovery device, the inlet end of which is connected to the outlet end of the secondary filter;

[0021] The reverse osmosis unit is connected to the outlet of the wastewater recovery unit. The reverse osmosis unit is used to purify the sewage in the wastewater recovery unit to obtain clean water.

[0022] A water pump is installed between the outlet of the wastewater recovery device and the inlet of the reverse osmosis device. The water pump is used to draw sewage from the wastewater recovery device into the reverse osmosis device.

[0023] In one embodiment, the drying system includes:

[0024] The multi-layer drying box has its inlet end connected to the outlet end of the wet coal slime collector and the outlet end of the secondary filter via connectors. The multi-layer drying box is equipped with multiple partitions, and the drying space is formed by the adjacent partitions and the inner wall of the multi-layer drying box. The drying space is used to dry coal slime of the corresponding particle size to obtain coal slag of the corresponding particle size.

[0025] In one embodiment, the drying system further includes a coal sample collector connected to the outlet end of a multi-layer drying chamber, the coal sample collector being used to collect and store the dried coal slag.

[0026] In one embodiment, the coal washing system includes:

[0027] The coal crushing and screening device has a raw coal inlet at one end. The coal crushing and screening device is used to crush and screen the raw coal to process the raw coal into coal powder suitable for water washing.

[0028] Coal conveyor belt; coal conveyor belt is used to transport pulverized coal.

[0029] The water supply tank is connected to the outlet of the external water source and wastewater circulation system.

[0030] The washing tank is connected to the water supply tank and the outlet end of the coal conveyor belt;

[0031] An agitator is installed inside the washing tank. The agitator is used to stir the mixture of coal powder and water to obtain coal-water slurry.

[0032] The heating device is located at the bottom of the washing tank and is used to heat the coal-water slurry.

[0033] In one embodiment, a weight sensing device is provided on the coal conveyor belt to control the weight of the conveyed coal powder; a liquid flow meter and a flow feedback device are connected between the water supply tank and the washing tank, and the flow feedback device is used to feed back the flow data monitored by the liquid flow meter to the control center of the high-alkali coal pretreatment system.

[0034] The aforementioned high-alkali coal pretreatment system includes a coal washing system, a solid-liquid separation system, and a drying system. The coal washing system is used to crush and wash the high-alkali coal to obtain a coal-water slurry. The solid-liquid separation system is connected to the outlet of the coal washing system and is used to filter the coal-water slurry to obtain coal slime of different particle sizes. The solid-liquid separation system includes a secondary filter, which is used to further filter the coal-containing wastewater after filtration by the solid-liquid separation system to obtain fine coal slime. The drying system is connected to the outlet of the solid-liquid separation system and is used to simultaneously dry the coal slime and fine coal slime of different particle sizes to obtain coal slag. This application obtains coal slime of different particle sizes through the solid-liquid separation system, which helps to reduce the amount of fine-particle coal slag waste in the coal slime water. Furthermore, the secondary filter further filters the coal-containing wastewater after filtration by the solid-liquid separation system, which helps to further reduce the amount of fine-particle coal slag waste in the coal slime water, thereby saving resources and helping to protect the environment. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a high-alkali coal pretreatment system in some embodiments of this application.

[0037] Explanation of icon numbers:

[0038] 100. Coal washing system; 110. Coal crushing and screening device; 120. Coal conveyor belt; 130. Water supply tank; 132. Water suction pump; 134. Check valve; 136. Regulating valve; 140. Washing tank; 150. Agitator; 160. Heating device; 162. Temperature detector; 170. Liquid flow meter; 180. Flow feedback device; 190. Fresh water replenishment tank; 200. Solid-liquid separation system; 210. Secondary filter; 220. Separation container body; 230. Wet coal slime collector; 240. Coal-containing wastewater tank; 300. Drying system; 310. Drying oven; 320. Coal sample collector; 400. Wastewater circulation system; 410. Wastewater recovery device; 420. Reverse osmosis device; 430. Water pump; 440. Flow meter. Detailed Implementation

[0039] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0043] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] To address the problem of resource waste and environmental pollution caused by the discarding of fine-particle coal slurry water during the high-alkali coal washing process in related technologies, this paper refers to... Figure 1 One embodiment of this application provides a high-alkali coal pretreatment system, including a coal washing system 100, a solid-liquid separation system 200, and a drying system 300. The coal washing system 100 is used to crush and wash high-alkali coal to obtain a coal-water slurry. The solid-liquid separation system 200 is connected to the outlet end of the coal washing system 100 and is used to filter the coal-water slurry to obtain coal slime of different particle sizes. The solid-liquid separation system 200 includes a secondary filter 210, which is used to filter the coal-containing wastewater after filtration by the solid-liquid separation system 200 again to obtain fine coal slime. The drying system 300 is connected to the outlet end of the solid-liquid separation system 200 and is used to simultaneously dry coal slime and fine coal slime of different particle sizes to obtain coal slag.

[0046] The coal washing system 100, solid-liquid separation system 200, and drying system 300 are sequentially connected via transmission pipelines. The coal-water slurry obtained from the coal washing system 100 contains coal slime of various particle sizes. After preliminary filtration by the solid-liquid separation system 200, coal slime of the same particle size can be screened together. The coal-containing wastewater after filtration by the solid-liquid separation system 200 can be filtered again by the secondary filter 210 to obtain coal slime with smaller particle size. After drying by the drying system 300, coal slag that meets the usage standards can be obtained. In this way, the coal content in the coal-containing wastewater is further reduced to reduce resource waste, which helps to protect the environment.

[0047] In this embodiment, coal slime of different particle sizes is obtained through the solid-liquid separation system 200, which helps to reduce the amount of fine-particle coal slag in the coal slime water. The coal-containing wastewater after being filtered by the solid-liquid separation system 200 is filtered again through the secondary filter 210, which helps to further reduce the amount of fine-particle coal slag in the coal slime water. This achieves resource conservation and helps to protect the environment.

[0048] Reference Figure 1In some embodiments, the coal washing system 100 includes a coal crushing and screening device 110, a coal conveying belt 120, a water tank 130, a washing tank 140, an agitator 150, and a heating device 160. The coal crushing and screening device 110 has a raw coal inlet at one end and is used to crush and screen the raw coal to process it into coal powder suitable for washing. The coal conveying belt 120 is used to convey the coal powder. The water tank 130 is connected to an external water source and the outlet of a wastewater circulation system 400. The washing tank 140 is connected to both the water tank 130 and the outlet of the coal conveying belt 120. The agitator 150 is located inside the washing tank 140 and is used to agitate the mixture of coal powder and water to obtain a coal-water slurry. The heating device 160 is located at the bottom of the washing tank 140 and is used to heat the coal-water slurry.

[0049] The coal crushing and screening device 110 includes a coal crusher, a vibrating feeder, and a vibrating screen. The coal conveyor belt 120 conveys pulverized coal through a conveying device. Specifically, the conveying device includes a frame, a motor mounted on the frame, and two rotating shafts. The rotating shafts are rotatably connected to the frame. The coal conveyor belt 120 is wound between the two rotating shafts, and the motor shaft is coaxially and fixedly connected to one of the rotating shafts. A weight sensor is also installed on the coal conveyor belt 120 to control the weight of the conveyed pulverized coal. The water supply tank 130 can be connected to an external water source via a water pump 132. A one-way valve 134 is provided at the port where the water supply tank 130 connects to the coal conveyor belt 120 to prevent backflow. A liquid flow meter 170 and a flow feedback device 180 are connected between the water supply tank 130 and the washing tank 140. The flow feedback device 180 is used to feed back the flow data monitored by the liquid flow meter 170 to the control center of the high-alkali coal pretreatment system. In addition, a regulating valve 136 is also connected between the liquid flow meter 170 and the washing tank 140. The regulating valve 136 is used to adjust the flow rate from the water supply tank 130 into the washing tank 140 according to the flow data adjustment instructions issued by the control center.

[0050] The agitator 150 includes an agitator shaft, an agitator paddle, and a drive motor. Specifically, the agitator shaft penetrates the inner top wall of the washing tank 140 and is rotatably connected to the washing tank 140. One end of the agitator shaft extends into the washing tank 140 and extends towards the inner bottom wall of the washing tank 140. The agitator paddle has multiple blades and is fixedly connected to the peripheral side wall at the bottom end of the agitator shaft. The drive motor is located on the inner or outer top wall of the washing tank 140, and the motor shaft of the drive motor is coaxially and fixedly connected to the top end of the agitator shaft. The drive motor can control the rotational speed of the agitator shaft. In addition, the agitator shaft in this embodiment can be raised and lowered. Specifically, the raising and lowering of the drive motor can be controlled by a cylinder installed outside the washing tank 140. The telescopic shaft of the cylinder is fixedly connected to the drive motor, and the cylinder can be stably placed above the washing tank 140 by a bracket. The heating device 160 can be an electric heater installed at the bottom of the washing tank 140, and the inner bottom wall of the washing tank 140 is equipped with a temperature detector 162, such as a thermometer, to monitor the washing temperature in real time and send the monitoring data to the control center so that the control center can adjust the washing temperature according to the monitoring data. The whole washing process is highly automated and simple to operate.

[0051] Specifically, during the water washing process, the high-alkali coal raw material is first crushed and screened using a coal crushing and screening device 110 to obtain coal powder. Then, the coal powder is conveyed to the water washing tank 140 via a coal conveyor belt 120. At the same time, a water supply tank 130 supplies water to the water washing tank 140. During water supply, the amount of water entering the water washing tank 140 can be controlled by the cooperation of a liquid flow meter 170, a regulating valve 136, and a flow feedback device 180 to maintain the liquid-solid ratio in the water washing tank 140 within the range of 10:1 to 20:1. The solid-liquid mixture in the water washing tank 140 is thoroughly stirred by a liftable stirring shaft. In addition, the water washing heating temperature can be controlled at 20℃ to 80℃ by a heating device 160, thereby improving the thoroughness of stirring. The centrifugal force generated by the rotation of the coal-water slurry is used to remove water-soluble alkaline metal oxides from the high-alkali coal, thereby improving the pretreatment effect of the high-alkali coal.

[0052] Reference Figure 1In some embodiments, the solid-liquid separation system 200 further includes a separation container body 220, multiple layers of filter screens with different pore sizes, a wet coal slime collector 230, and multiple coal slime collection components. The separation container body 220 is connected to the outlet end of the coal washing system 100 to obtain coal-water slurry, and the separation container body 220 is provided with a first outlet end. Multiple layers of filter screens with different pore sizes are distributed vertically from top to bottom on the inner wall of the separation container body 220, and the pore size of each filter screen gradually decreases from top to bottom. The wet coal slime collector 230 is connected to the first outlet end to collect coal slime of different particle sizes, and the outlet end of the wet coal slime collector 230 is connected to the drying system 300. The coal slime collection components are arranged one-to-one with the filter screens, and the coal slime collection components are used to periodically transfer the coal slime on each filter screen to the wet coal slime collector 230.

[0053] The separation container body 220 has two outlet ends: a first outlet end and a second outlet end. The first outlet end is located on the side wall of the separation container body 220, and the second outlet end is located at the bottom of the separation container body 220. The second outlet end is connected to a coal-containing wastewater tank 240, and the outlet end of the coal-containing wastewater tank 240 is connected to the inlet of the secondary filter 210. The coal-containing wastewater tank 240 is used to store coal-containing wastewater and plays a certain role in the sedimentation of the coal-containing wastewater. The coal-water slurry enters the separation container body 220 through the opening at the top. The filter screen can be set horizontally inside the separation container body 220 or inclined towards the first outlet end. Since the coal-water slurry is filtered vertically from top to bottom, the pore size of the filter screen gradually decreases from top to bottom.

[0054] The coal slime collection components are configured one-to-one with the filter plates, so that each component only needs to collect the coal slime deposited on its corresponding filter plate. Because the particle size of the coal slime collected on each filter plate is different, the time it takes for a coal slime pile of the same size to accumulate on each plate is also different. Therefore, the collection cycle for each coal slime collection component on its corresponding filter plate can be pre-set according to actual conditions. Also because the time for a coal slime pile of the same size to accumulate on each filter plate is different, a wet coal slime collector 230 is set up to temporarily collect and store coal slime of different particle sizes for subsequent unified delivery into the drying system 300 for drying.

[0055] Specifically, the open end of the separation container body 220 is connected to the outlet end of the washing water tank. Taking three layers of filter screens with different pore sizes as an example, with the pore sizes of the filter screens from top to bottom being 1mm, 0.5mm and 0.1mm respectively, after the coal-water slurry is filtered through multiple layers of filter screens with different pore sizes, it becomes coal-containing wastewater that settles to the bottom of the separation container body 220. Coal slurry of corresponding particle sizes is obtained on each layer of filter screens. When the amount of coal slurry accumulated on the filter screens reaches a certain amount, or according to experience after the coal slurry has been deposited for a certain period of time, the accumulation amount is assumed to meet the discharge requirements. For example, every 20 minutes, the corresponding coal slurry collection component scrapes the accumulated coal slurry on a certain layer of filter screens into the wet coal slurry collector 230 for temporary storage.

[0056] In addition, the coal-containing wastewater obtained after filtration by the main body of the separation container 220 enters the secondary filter 210 from the second outlet end. The secondary filter 210 can perform negative pressure air filtration on the coal-containing wastewater to obtain a filter cake formed by negative pressure of fine coal slime. The filter cake can be conveyed to the drying system 300 for drying by a conveyor belt.

[0057] In this embodiment, the coal-water slurry is filtered through multiple layers of filter screens with different pore sizes. This not only yields coal slime of different particle sizes but also reduces the coal content in the coal-containing wastewater, thereby saving resources and helping to protect the environment.

[0058] Reference Figure 1 In some embodiments, the coal slime collection assembly includes a movable scraper and a drive unit. The movable scraper is disposed at one end of a corresponding filter plate. The drive unit is connected to the movable scraper and is used to drive the movable scraper to move along the length of the filter plate to transfer the coal slime on the filter plate into the drying system 300.

[0059] The driving component includes a driving cylinder, which is installed on the outer side wall of the separation container body 220. The driving end of the driving cylinder passes through the side wall of the separation container body 220 away from the first outlet end and is fixedly connected to the moving scraper, thereby realizing the reciprocating motion of the moving scraper along the length direction of the filter screen plate and pushing the coal sludge accumulated on the filter screen plate from the first outlet end of the separation container body 220 into the drying system 300.

[0060] Specifically, the drying system 300 includes a multi-layer drying chamber 310. The inlet end of the multi-layer drying chamber 310 is connected to the outlet end of the wet coal slime collector 230 and the outlet end of the secondary filter 210 via a connector. The connector includes a conveyor belt for conveying coal slime. The multi-layer drying chamber 310 is equipped with multiple partitions. Adjacent partitions and the inner wall of the multi-layer drying chamber 310 enclose a drying space. The drying space is used to dry coal slime of corresponding particle size to obtain coal slag of corresponding particle size. Each drying space is equipped with a temperature control and timing unit, which is connected to a control center. The drying temperature range of the coal slime is 60℃ to 105℃, and the drying time lasts from 40 min to 120 min.

[0061] In this embodiment, the outlet end of the secondary filter 210 is connected to the drying system 300, so that the fine coal slurry filtered by the secondary filter 210 and the coal slurry filtered by the separation container body 220 can be conveyed to the multi-layer drying box 310 via a conveyor belt. When conveyed to the multi-layer drying box 310, the drying temperature and drying time in different drying spaces can be set according to the particle size of the coal slurry. This ensures that coal slurry of various particle sizes can be fully dried, while also saving resources and reducing energy waste.

[0062] Reference Figure 1 In some embodiments, the drying system 300 further includes a coal sample collector 320, which is connected to the outlet end of the multi-layer drying box 310. The outlet end of the multi-layer drying box 310 can be located on the side wall of the multi-layer drying box 310 away from the inlet end of the multi-layer drying box 310. The coal sample collector 320 is used to collect and store the dried coal slag.

[0063] Specifically, wet coal slime and filter cake can be dried to obtain coal slag. The coal sample collector 320 can collect coal slag of different particle sizes separately or at the same time, depending on the actual usage requirements.

[0064] Reference Figure 1 In some embodiments, the high-alkali coal pretreatment system also includes a wastewater circulation system 400. The inlet end of the wastewater circulation system 400 is connected to the outlet end of the secondary filter 210, and the outlet end of the wastewater circulation system 400 is connected to the inlet end of the coal washing system 100. The wastewater circulation system 400 is used to purify the wastewater filtered by the secondary filter 210 to obtain clean water, and then transfer the clean water to the coal washing system 100.

[0065] Specifically, the wastewater recycling system 400 is used to purify the coal-containing wastewater again to obtain clean water, which is then transferred to the coal washing system 100. This helps to deeply recycle and reuse the coal washing wastewater, thereby effectively solving the problem of high water consumption in the pretreatment process of high-alkali coal.

[0066] Reference Figure 1 In some embodiments, the wastewater recycling system 400 includes a wastewater recovery device 410, a reverse osmosis device 420, and a water pump 430. The inlet end of the wastewater recovery device 410 is connected to the outlet end of the secondary filter 210, and the inlet end of the reverse osmosis device 420 is connected to the outlet end of the wastewater recovery device 410. The reverse osmosis device 420 is used to purify the wastewater in the wastewater recovery device 410 to obtain clean water. The water pump 430 is disposed between the outlet end of the wastewater recovery device 410 and the inlet end of the reverse osmosis device 420, and is used to pump the wastewater in the wastewater recovery device 410 into the reverse osmosis device 420.

[0067] The reverse osmosis unit 420 is a reverse osmosis filter. A pressurizing device can be installed inside the reverse osmosis filter. The pressure applied by the pressurizing device is determined by the volume of purified water to ensure an extended service life of the reverse osmosis membrane. A flow meter 440 is also connected between the reverse osmosis unit 420 and the water pump 430 to monitor the wastewater flow rate. Additionally, the wastewater circulation system 400 includes a fresh water replenishment tank 190. The bottom of the fresh water replenishment tank 190 is connected to the front end of the reverse osmosis unit 420 via a pipeline to replenish fresh water as needed, thereby maintaining osmotic pressure.

[0068] Specifically, the wastewater in the wastewater recycling device 410 passes through the water pump 430 and the flow meter 440 in sequence, and then enters the reverse osmosis device 420 for purification. After becoming clean water, it enters the water supply tank 130 as supplementary water, thereby realizing the recycling of wastewater.

[0069] In one detailed embodiment, the high-alkali coal pretreatment system first crushes and screens the high-alkali coal raw material through a coal crushing and screening device 110 to obtain 3-5mm coal powder. Then, the coal powder is conveyed to the washing tank 140 by a coal conveyor belt 120. At the same time, the water supply tank 130 supplies water to the washing tank 140. During water supply, the amount of water entering the washing tank 140 can be controlled by the cooperation of a liquid flow meter 170, a regulating valve 136, and a flow feedback device 180 to maintain the liquid-solid ratio in the washing tank 140 at 15:1. The amount of coal processed at one time is 20kg. A one-way valve 134 is used to control the return flow. The speed of the agitator 150 is set to 1500 r / min. The water washing temperature is controlled at 70℃ by a heating device 160. During the removal of water-soluble alkaline metal oxides from the high-alkali coal, the water washing temperature is fed back by a temperature detector 162, and real-time dynamic temperature adjustment is performed. After 1 hour of sodium removal washing, the coal slurry water is transported to the main body of the separation container 220 for coarse screening. The filter screens have apertures of 1 mm, 0.5 mm, and 0.1 mm from top to bottom. Moving scrapers corresponding to each filter screen scrape the accumulated coal slurry onto the filter screens every 20, 25, and 30 minutes, respectively, into the coal slurry collector. This separation process separates 70% of the coal particles. The wet coal slurry in the collector is then transferred to a multi-layer drying oven 310 for drying. The filtrate, i.e., the coal slurry wastewater, still contains a significant amount of fine-diameter coal particles. The filtrate is then introduced from the main body of the separation container 220 into a secondary filter 210 for fine coal filtration. The resulting filter cake is then fed into a multi-layer drying chamber 310 for drying. The temperature and drying time in each chamber 310 can be controlled independently. For example, for wet coal slime with larger particle sizes, the drying temperature can be set at 115℃ for 1.8 hours; for wet coal slime with smaller particle sizes, the drying temperature can be set at 100℃ for 2 hours. This process increases the degree of coal-water separation, achieving a total coal powder recovery rate of over 95%. Subsequently, the wastewater is treated by reverse osmosis in a wastewater recovery device 410. After reverse osmosis filtration, the wastewater is used as supplementary water in the feed water tank 130, thus achieving wastewater recycling and resource conservation. Through this treatment process, the alkali metal removal efficiency in high-alkali coal reaches 55%.

[0070] In another detailed embodiment, a high-alkali coal pretreatment system is used to pretreat high-ash, high-alkali coal co-fired in a circulating fluidized bed. First, high-alkali coal with a particle size range of less than 5 mm is screened out and then fed into a washing tank 140 with water at a liquid-to-solid ratio of 10:1. The coal volume processed at one time is 30 kg. A one-way valve 134 is used to prevent backflow. The stirring shaft speed is set to 1000 r / min, and the temperature of the heating device 160 is controlled at 60°C. During the removal process, the washing temperature is fed back by a temperature detector 162 for real-time dynamic temperature adjustment. After 40 minutes of washing, the coal slime is conveyed to a coarse separator with a coarse screen. The filter screen has apertures of 1 mm, 0.5 mm, and 0.1 mm from top to bottom. A moving scraper is installed at the front end of the three-layer filter screen, scraping the coal slime to a wet coal slime collector 230 every 20 minutes. This separation step separates 75% of the coal particles. Since some circulating fluidized beds use coal slurry for blending, the screened wet coal slime can be remixed with water to prepare coal slime paste for later use. The filtrate contains many fine coal particles; it is introduced from the coal-containing wastewater tank 240 into the secondary filter 210 for fine coal filtration. The filtered coal slime cake, requiring drying, enters the multi-layer drying oven 310 and is dried at 105℃ for 2 hours. Subsequently, the wastewater is purified by reverse osmosis through the wastewater recovery device 410. After reverse osmosis filtration, the purified water is used as makeup water for the feed water tank 130. During this process, fresh water is continuously replenished to the reverse osmosis front end through the fresh water replenishment tank 190, thus helping to reduce the amount of fine-particle coal slag in the coal slime water, saving resources and protecting the environment.

[0071] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0072] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A high-alkali coal pretreatment system, characterized in that, The high-alkali coal pretreatment system includes: The coal washing system is used to crush and wash high-alkali coal to obtain coal-water slurry; A solid-liquid separation system is connected to the outlet end of the coal washing system. The solid-liquid separation system is used to filter the coal-water slurry to obtain coal slime of different particle sizes. The solid-liquid separation system includes a secondary filter, which is used to filter the coal-containing wastewater after the solid-liquid separation system to obtain fine coal slime. A drying system, connected to the outlet of the solid-liquid separation system, is used to simultaneously dry coal slime and fine coal slime of different particle sizes to obtain coal slag.

2. The high-alkali coal pretreatment system according to claim 1, characterized in that, The solid-liquid separation system also includes: The main body of the separation container is connected to the outlet end of the coal washing system to obtain the coal-water slurry, and the main body of the separation container is provided with a first outlet end; Multiple filter screens with different pore sizes are distributed vertically from top to bottom on the inner wall of the separation container body, and the pore size of each filter screen gradually decreases from top to bottom; A wet coal slime collector is connected to the first outlet end to collect coal slime of different particle sizes, and the outlet end of the wet coal slime collector is connected to the drying system. Multiple coal sludge collection components are provided, each corresponding to a filter screen plate. The coal sludge collection components are used to periodically transfer the coal sludge on each of the filter screen plates into the wet coal sludge collector.

3. The high-alkali coal pretreatment system according to claim 2, characterized in that, The coal slime collection assembly includes: A movable scraper is disposed at one end of the corresponding filter plate; A driving component, connected to the movable scraper, is used to drive the movable scraper to move along the length of the filter screen to transfer the coal slime on the filter screen into the drying system.

4. The high-alkali coal pretreatment system according to claim 2, characterized in that, The separation container body is also provided with a second outlet end. The inlet of the secondary filter is connected to the second outlet end, and the outlet end of the secondary filter is connected to the drying system. The secondary filter is used to perform negative pressure air filtration on the coal-containing wastewater filtered in the separation container body to obtain the filter cake formed by negative pressure of the fine coal slime.

5. The high-alkali coal pretreatment system according to claim 4, characterized in that, The high-alkali coal pretreatment system also includes a wastewater circulation system. The inlet of the wastewater circulation system is connected to the outlet of the secondary filter, and the outlet of the wastewater circulation system is connected to the inlet of the coal washing system. The wastewater circulation system is used to purify the wastewater filtered by the secondary filter to obtain clean water, and then transfer the clean water to the coal washing system.

6. The high-alkali coal pretreatment system according to claim 5, characterized in that, The wastewater recycling system includes: A wastewater recovery device, wherein the inlet end of the wastewater recovery device is connected to the outlet end of the secondary filter; A reverse osmosis device, wherein the inlet end of the reverse osmosis device is connected to the outlet end of the wastewater recovery device, and the reverse osmosis device is used to purify the wastewater in the wastewater recovery device to obtain the purified water; A water pump is installed between the outlet end of the wastewater recovery device and the inlet end of the reverse osmosis device. The water pump is used to pump the sewage in the wastewater recovery device into the reverse osmosis device.

7. The high-alkali coal pretreatment system according to claim 4, characterized in that, The drying system includes: A multi-layer drying chamber is provided, wherein the inlet end of the multi-layer drying chamber is connected to the outlet end of the wet coal slime collector and the outlet end of the secondary filter via a connector. The multi-layer drying chamber is provided with multiple partitions, and the drying space is formed between the adjacent partitions and the inner wall of the multi-layer drying chamber. The drying space is used to dry the coal slime of the corresponding particle size to obtain coal slag of the corresponding particle size.

8. The high-alkali coal pretreatment system according to claim 7, characterized in that, The drying system also includes a coal sample collector connected to the outlet end of the multi-layer drying chamber, which is used to collect and store the dried coal slag.

9. The high-alkali coal pretreatment system according to claim 5, characterized in that, The coal washing system includes: A coal crushing and screening device, wherein one end of the coal crushing and screening device is provided with a raw coal inlet, and the coal crushing and screening device is used to crush and screen the raw coal to process the raw coal into coal powder suitable for water washing. A coal conveyor belt for conveying the pulverized coal; The water supply tank is connected to an external water source and the outlet of the wastewater circulation system. A water washing tank is connected to the water supply tank and the outlet end of the coal conveyor belt; An agitator is installed inside the washing tank. The agitator is used to agitate the mixture of pulverized coal and water to obtain the coal-water slurry. A heating device is installed at the bottom of the washing tank to heat the coal-water slurry.

10. The high-alkali coal pretreatment system according to claim 9, characterized in that, The coal conveyor belt is equipped with a weight sensing device, which is used to control the weight of the conveyed coal powder; a liquid flow meter and a flow feedback device are connected between the water supply tank and the water washing tank, and the flow feedback device is used to feed back the flow data monitored by the liquid flow meter to the control center of the high-alkali coal pretreatment system.

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