System and method for monitoring, purifying and recycling pulverized coal in coal separation process

Abstract

The invention discloses a system and a method for monitoring, purifying and recycling pulverized coal in a coal separation process, and relates to the field of dry separation and upgrading of high-water-content coal, and the system comprises pretreatment equipment which can perform screening and impurity removal on raw coal and crush the raw coal until the granularity is smaller than a set value; the X-ray sorting equipment can be used for sorting materials with the particle size larger than 100mm in the raw coal; the drying equipment can receive and dry raw coal with the particle size smaller than 100 mm. The dry separation equipment can be used for screening the dried raw coal; the air dense medium fluidized bed separation equipment can receive and screen the raw coal which is screened by the dry separation equipment and has the granularity smaller than 13mm; the medium recovery and purification equipment can be used for recovering and recycling heavy media carried in products separated by the air heavy medium fluidized bed separation equipment; and the air inducing and dust removing equipment can be used for recycling pulverized coal generated by all the equipment, and discharging air with qualified dust concentration to the atmosphere. The full-size coal sorting machine can adapt to full-size coal sorting.

Description

Technical Field

[0001] This invention relates to the field of dry sorting and upgrading technology for high-moisture coal, and in particular to a coal powder monitoring, purification and recovery system and method for the coal sorting process. Background Technology

[0002] After coal mining, the particles vary in size and contain many impurities, thus requiring sorting. Currently, traditional heavy media coal preparation plants for thermal coal generally employ a partial washing process, sorting only lump coal larger than 13mm / 6mm, while fine coal smaller than 13mm / 6mm is often bypassed and discharged directly without washing. This model has significant limitations: firstly, lump coal larger than 13mm / 6mm often has high gangue content, high ash content, and low calorific value, making it impossible to meet the quality requirements of downstream users without effective sorting; secondly, fine coal smaller than 13mm / 6mm accounts for 60%-70% or even higher of the total raw coal volume. Directly abandoning sorting not only results in a serious waste of high-quality coal resources but also significantly reduces its comprehensive utilization value due to the high ash and moisture content of the fine coal.

[0003] Even though some companies have attempted to wash and separate fine coal, they still face numerous challenges. While washing fine coal reduces ash content, the reduction is limited, and the washing process significantly increases the moisture content of the clean coal, resulting in a poor improvement in its calorific value. More importantly, the complete separation of fine coal generates a large amount of coal slime, which not only increases the investment and operating costs of the coal slime water treatment system but also further reduces the clean coal yield due to difficulties in slime dewatering. For low-rank coal, the impact of moisture changes on calorific value is more pronounced; a 1% increase or decrease in moisture has a greater impact on calorific value than a 1% increase or decrease in ash content. This is because moisture consumes additional calorific value for latent heat of vaporization during combustion and directly reduces the relative content of organic matter.

[0004] Furthermore, the mixing of coal into the roof and floor, gangue interlayers, and the re-crushing during washing, processing, and transportation further exacerbate the complexity of coal quality. Especially when the gangue consists of easily mud-forming minerals such as argillaceous shale, mud formation is highly likely to occur during water washing, not only contaminating the clean coal product but also clogging sorting equipment and pipelines, severely impacting the continuity and stability of production.

[0005] In conclusion, there is an urgent need to design a technical solution that can adapt to the separation of coal of all particle sizes. Summary of the Invention

[0006] The purpose of this invention is to provide a coal powder monitoring, purification and recovery system and method for coal sorting process, so as to solve the problems existing in the prior art and be able to adapt to coal sorting of all particle sizes.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a coal powder monitoring and purification recovery system for coal sorting processes, comprising: Pre-treatment equipment can screen and remove impurities from raw coal and crush it to a particle size smaller than a set value; X-ray sorting equipment can sort materials with a particle size greater than 100mm in raw coal; Drying equipment capable of receiving and drying raw coal with a particle size of less than 100mm; Dry sorting equipment can screen dried raw coal to separate raw coal with a particle size between 100mm and 13mm. The air-heavy medium fluidized bed separator is capable of receiving raw coal with a particle size of less than 13mm that has been screened by the dry separator and performing screening. The media recovery and purification equipment is capable of recovering and recycling the weighted mass carried in the products separated by the air-heavy media fluidized bed separator; and The exhaust dust removal equipment can recover dust from coal powder generated by X-ray sorting equipment, drying equipment, dry sorting equipment, air-heavy medium fluidized bed sorting equipment, and medium recovery and purification equipment, and discharge qualified dust-concentrated air into the atmosphere.

[0008] In one embodiment, the pretreatment equipment includes a 200mm grading screen, an iron remover, a crusher, and a 100mm grading screen; the inlet of the 200mm grading screen is connected to a raw coal belt conveyor, the outlet of the 200mm grading screen is connected to the iron remover on the screen and the crusher under the screen, the crusher is connected to the belt conveyor of the 100mm grading screen, the outlet of the 100mm grading screen is connected to an X-ray sorting device, and the outlet of the 100mm grading screen is connected to the drying equipment.

[0009] In one embodiment, the X-ray sorting equipment includes: a first buffer chamber, a first coal feeder, and an X-ray intelligent sorting device; the inlet of the first buffer chamber is connected to the outlet of the 100mm grading screen, the outlet of the first buffer chamber is connected to the inlet of the first coal feeder, the outlet of the first coal feeder is connected to the inlet of the X-ray intelligent sorting device, and the outlet of the X-ray intelligent sorting device is connected to a first clean coal product belt conveyor and a first gangue product belt conveyor, respectively, so as to transport the sorted clean coal and gangue separately.

[0010] In one embodiment, the drying equipment includes a second buffer chamber, a second coal feeder, a low-temperature steam drying device, and a third buffer chamber; the inlet of the second buffer chamber is connected to the undersize outlet of the 100mm grading screen, the outlet of the second buffer chamber is connected to the inlet of the second coal feeder, the outlet of the second coal feeder is connected to the inlet of the low-temperature steam drying device, the outlet of the low-temperature steam drying device is connected to the inlet of the third buffer chamber via a belt conveyor, and the outlet of the third buffer chamber is connected to the dry sorting equipment.

[0011] In one embodiment, the dry separation equipment includes a third coal feeder, a 13mm / 6mm grading screen, and a dry separation device; the outlet of the drying equipment is connected to the inlet of the third coal feeder, the outlet of the third coal feeder is connected to the inlet of the 13mm / 6mm grading screen, the oversize outlet of the 13mm / 6mm grading screen is connected to a belt conveyor at the inlet of the air-heavy medium fluidized bed separation equipment, the undersize outlet of the 13mm / 6mm grading screen is connected to the inlet of the dry separation device, and the outlet of the dry separation device is connected to a second clean coal belt conveyor and a second gangue belt conveyor, respectively, to transport the separated clean coal and gangue separately.

[0012] In one embodiment, the air-heavy medium fluidized bed separation equipment includes a fourth buffer chamber, a fourth coal feeder, and an air-heavy medium fluidized bed separation device. The inlet of the fourth buffer chamber is connected to a belt conveyor at the screen outlet of the 13mm / 6mm grading screen, the outlet of the fourth buffer chamber is connected to the inlet of the fourth coal feeder, the outlet of the fourth coal feeder is connected to the inlet of the air-heavy medium fluidized bed separation device, the outlet of the air-heavy medium fluidized bed separation device is connected to a 2mm gangue desliming screen and a 2mm clean coal desliming screen, the processing of the 2mm gangue desliming screen is connected to a third gangue belt conveyor, and the outlet of the 2mm clean coal desliming screen is connected to a third clean coal belt conveyor.

[0013] In one embodiment, the media recovery and purification equipment includes a diverter, a fifth buffer chamber, a fifth coal feeder, a sixth buffer chamber, a fifth coal feeder, a magnetic separator, a seventh buffer chamber, a seventh coal feeder, the 2mm gangue desliming screen, and the 2mm clean coal desliming screen. The diverter inlet is connected to the belt conveyor at the outlet of the 2mm gangue desliming screen and the belt conveyor at the outlet of the 2mm clean coal desliming screen, respectively. The diverter outlet is connected to the inlet of the fifth buffer chamber and the inlet of the sixth buffer chamber, respectively. The outlet of the fifth buffer chamber is connected to the inlet of the fifth coal feeder. The outlet of the fifth coal feeder is connected to the media recovery inlet of the air-heavy media fluidized bed separator. The outlet of the sixth buffer chamber is connected to the inlet of the sixth coal feeder. The outlet of the sixth coal feeder is connected to the inlet of the magnetic separator. The outlet of the magnetic separator is connected to the media replenishment chamber. The outlet of the media replenishment chamber is connected to the inlet of the seventh buffer chamber. The outlet of the seventh buffer chamber is connected to the inlet of the seventh coal feeder. The outlet of the seventh coal feeder is connected to the media recovery inlet of the air-heavy media fluidized bed separator.

[0014] In one embodiment, the induced draft dust removal equipment includes a first dust collector, a first induced draft fan, a second dust collector, a second induced draft fan, an air valve, an air receiver, and a blower. The inlet of the first dust collector is connected to the dust removal pipeline of the drying equipment, the outlet of the first dust collector is connected to the inlet of the first induced draft fan, and the outlet of the first induced draft fan is connected to the outside to discharge qualified air to the external environment. The inlet of the second dust collector is connected to the dust removal pipelines of an X-ray sorting device, a dry sorting device, and an air-heavy medium fluidized bed sorting device, respectively. The outlet of the second dust collector is connected to the inlet of the second induced draft fan, and the outlet of the second induced draft fan is connected to the outside to discharge qualified air to the external environment. The inlet of the blower is connected to the outside, the outlet of the blower is connected to the air receiver, and the air receiver is connected to the air-heavy medium fluidized bed sorting device through a pipeline equipped with an air valve.

[0015] In one embodiment, the air-heavy medium fluidized bed separator is equipped with a pressure gauge, which can monitor the density and height in the air-heavy medium fluidized bed separator in real time, and provide feedback and adjust the operating parameters of the air-heavy medium fluidized bed separator.

[0016] This invention also provides a method for monitoring, purifying, and recovering pulverized coal during the coal sorting process, comprising the following steps: Raw coal is screened to remove impurities and crushed to a particle size smaller than a set value. Dust samples are taken during the raw coal crushing process, then screened and analyzed to obtain the coal powder particle size classification. Materials with a particle size greater than 100mm in the raw coal are sorted by X-ray sorting equipment, and the sorted clean coal and gangue are transported to their respective storage locations. Materials with a particle size of less than 100mm in the raw coal are fed into the drying equipment for drying, and the particle size distribution and moisture content of the dried coal powder are sampled. After drying and sampling, the coal powder is sequentially fed into the dry separation equipment and the air-heavy medium fluidized bed separation equipment for separation. The separated clean coal and gangue are transported to the corresponding storage locations, and the coal powder generated during the separation process of the dry separation equipment and the air-heavy medium fluidized bed separation equipment is sampled and analyzed. After being separated by the air-heavy medium fluidized bed separator, the heavy medium is recovered and purified by the medium recovery and purification equipment, and then circulated back to the air-heavy medium fluidized bed separator. Samples are taken from the undersize materials of the 2mm gangue desliming screen and the 2mm clean coal desliming screen of the air-heavy medium fluidized bed separator to obtain the distribution results of magnetic material content and particle size distribution in the coal powder, thus indirectly evaluating the separation effect of the air-heavy medium fluidized bed separator. Yinfeng dust collectors were used to separate X-ray sorting equipment, drying equipment, dry sorting equipment, and air-heavy medium fluidized bed sorting equipment. Air with qualified dust concentration was discharged into the atmosphere. The coal powder stored in the dust collectors was sampled and tested multiple times to obtain the physical and chemical properties of the coal powder.

[0017] The present invention achieves the following technical effects compared to the prior art: This invention uses pretreatment equipment, drying equipment, sorting equipment, induced draft dust removal equipment, and media recovery and purification equipment to separate moisture-containing thermal coal into three particle sizes: 200-100mm, 100-13mm / 6mm, and 13-0mm / 6-0mm, resulting in coarse, medium, and fine products. These products are then fed into X-ray intelligent sorting equipment, high-efficiency dry sorting equipment, and air-heavy media fluidized bed sorting equipment, respectively. Coal powder generated at different stages of the sorting process is sampled and compared to obtain the coal powder characteristics of the entire process. This invention is suitable for sorting coal of all particle sizes and enables coal powder detection and utilization in the field of dry sorting. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the coal powder monitoring, purification and recovery method in one or more embodiments of the present invention. Figure 2 This is a schematic diagram of the structural layout of a coal powder monitoring, purification and recovery system in one or more embodiments of the present invention.

[0020] In the diagram: 1-200mm grading screen, 2-iron separator, 3-crusher, 4-100mm grading screen, 5-first buffer bin, 6-first coal feeder, 7-X-ray intelligent sorting device, 8-second buffer bin, 9-second coal feeder, 10-low temperature steam drying device, 11-third buffer bin, 12-third coal feeder, 13-first dust collector, 14-first induced draft fan, 15-13mm / 6mm grading screen, 16-dry sorting device; 17-fourth buffer bin 18-Fourth coal feeder, 19-Air-heavy medium fluidized bed separator, 20-Pressure gauge, 21-2mm gangue desliming screen, 22-2mm clean coal desliming screen, 23-Diverter, 24-Fifth buffer bin, 25-Fifth coal feeder, 26-Sixth buffer bin, 27-Sixth coal feeder, 28-Magnetic separator, 29-Seventh buffer bin, 30-Seventh coal feeder, 31-Second dust collector, 32-Second induced draft fan, 33-Air valve, 34-Air manifold, 35-Blower. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide a coal powder monitoring, purification and recovery system and method for coal sorting process, so as to solve the problems existing in the prior art and be able to adapt to coal sorting of all particle sizes.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 and Figure 2As shown, this invention provides a coal dust monitoring, purification, and recovery system for a coal sorting process, including a pretreatment device that can screen and remove impurities from raw coal and crush it to a particle size smaller than a set value, which is a particle size of less than 200mm. The pre-sorting screening and crushing are conducted in a closed environment to prevent the diffusion of large amounts of dust. An X-ray sorting device can sort materials with a particle size greater than 100mm in the raw coal. In this embodiment, it sorts materials with a particle size of 200-100mm, offering advantages such as a wide feed particle size range, large processing capacity, and a gangue removal rate of up to 95%. A drying device can receive and dry raw coal with a particle size less than 100mm. The drying process can remove most of the moisture from the coal, but over-drying should be avoided to prevent coal dust generation and safety accidents. The drying process indirectly dries high-moisture coal in -100mm raw coal using low-temperature steam drying. -100mm refers to a particle size less than 100mm, and the moisture content after drying is M. f The concentration can be reduced to below 8%, and no solid waste is generated during the drying process, thus reducing environmental pollution. The steam temperature is generally 90~150℃, reducing the risk of spontaneous combustion or explosion of pulverized coal. The steam after heat exchange condenses into water, which can be recycled after simple treatment. The dry separation equipment can screen the dried raw coal to separate raw coal with a particle size between 100mm and 13mm. In this embodiment, the 100-13mm / 100-6mm coal is separated after drying, which has the advantages of no water required in the drying process, simple separation process, and low cost. The air-heavy medium fluidized bed separation equipment can receive raw coal with a particle size of less than 13mm that has been screened by the dry separation equipment and screen it. In this embodiment, the 13-0mm / 6-0mm fine coal is separated, which has the advantages of high separation accuracy and large processing capacity. The media recovery and purification equipment can recover and recycle the weighting material carried in the products after separation by the air-heavy media fluidized bed separator. The media recovery and purification stage recovers and recycles the weighting material carried in 13-0mm / 6-0mm clean coal and 13-0mm / 6-0mm gangue products. The 2-0mm undersize material is fed into the magnetic separator 28 through a 2mm grading screen to recover pure magnetite powder weighting material. The remaining coal powder can be stored or fed into the air-heavy media fluidized bed separator to adjust the fluidized bed separation density. The induced draft dust removal equipment can recover dust from the coal powder generated by the X-ray separator, drying equipment, dry separator, air-heavy media fluidized bed separator, and media recovery and purification equipment. The recovered dust is stored in a dust collector, and air with a qualified dust concentration is discharged into the atmosphere.

[0025] After pre-selection screening and crushing, the raw coal to be selected yields 200-100mm and 100-0mm moisture-containing thermal coal. The 200-100mm moisture-containing thermal coal enters an X-ray intelligent dry separation device, while the 100-0mm moisture-containing thermal coal undergoes low-temperature steam drying to reduce its moisture content to below 8%. It then passes through a 13mm / 6mm grading screen. The 100-13mm / 6mm coal enters a dry separation device to obtain 100-13mm / 6mm clean coal and 100-13mm... 6mm / 13-0mm / 6-0mm gangue enters the air-heavy medium fluidized bed separator to obtain 13-0mm / 6-0mm clean coal and 13-0mm / 6-0mm gangue. The 13-0mm / 6-0mm product then passes through a 2mm grading sieve to obtain the undersize 2-0mm. A medium recovery device is then used to process the coal sample, achieving the separation and recycling of coal powder and magnetite powder. An induced draft dust removal device filters and collects the dust collected during the three particle size separation processes, yielding fine dust byproducts. This invention has significant advantages such as wide applicability, high-precision separation, and a complete all-particle-size beneficiation and upgrading process system.

[0026] In one embodiment, the pretreatment equipment includes a 200mm grading screen 1, an iron remover 2, a crusher 3, and a 100mm grading screen 4. The iron remover 2's main function is to remove iron and other impurities from the raw coal on the belt conveyor, protecting the normal operation of the equipment and improving the safety and efficiency of subsequent equipment. The inlet of the 200mm grading screen 1 is connected to the raw coal belt conveyor, and the outlet of the 200mm grading screen 1 is connected to the iron remover 2 on the screen and the crusher 3 on the screen. The crusher 3 is connected to the belt conveyor of the 100mm grading screen 4, the outlet of the 100mm grading screen 4 is connected to an X-ray sorting device, and the outlet of the 100mm grading screen 4 is connected to a drying device. Coal dust is generated during the sorting process in this stage. The coal dust has a high moisture content. By isolating the dust in a closed environment and using induced draft dust removal methods, the high-moisture dust by-product can be efficiently recovered and dusted. The particle size classification of the coal dust can be obtained by sampling, sieving, and testing the dust in this stage.

[0027] In one embodiment, the X-ray sorting equipment includes a first buffer chamber 5, a first coal feeder 6, and an X-ray intelligent sorting device 7. The inlet of the first buffer chamber 5 is connected to the outlet of the 100mm grading screen 4, the outlet of the first buffer chamber 5 is connected to the inlet of the first coal feeder 6, the outlet of the first coal feeder 6 is connected to the inlet of the X-ray intelligent sorting device 7, and the outlet of the X-ray intelligent sorting device 7 is connected to a first clean coal product belt conveyor and a first gangue product belt conveyor, respectively, to transport the sorted clean coal and gangue separately. The X-ray intelligent sorting device 7 uses an X-ray source to transmit X-rays through the coal and gangue on the belt conveyors. X-rays have strong penetrating power, but during the penetration process, the material absorbs the X-ray energy, resulting in energy loss. The intensity of energy loss is mainly affected by the material properties and thickness. Because the elemental composition and content of each element in coal and gangue differ greatly, the attenuation degree of X-rays during penetration will also be different, leading to differences in imaging. This allows for identification and pneumatic impact, achieving coal-gangue separation. The X-ray intelligent sorting device 7 mainly includes a feeding system, an X-ray recognition system, and a sorting system. Material is evenly spread in a single layer onto a belt conveyor via the feeding system and then transported to the X-ray recognition system. The X-ray emitter and detector detect the differences in X-ray absorption by coal and gangue, forming digital images of different grayscale levels. A laser, in conjunction with a high-speed camera, assists in image recognition and precise positioning of the material. A controlled jetting system interferes with the ore's trajectory, thereby achieving the separation of mineral waste from other materials.

[0028] In one embodiment, the drying equipment includes a second buffer chamber 8, a second coal feeder 9, a low-temperature steam dryer 10, and a third buffer chamber 11. The inlet of the second buffer chamber 8 is connected to the undersize outlet of a 100mm grading screen 4, the outlet of the second buffer chamber 8 is connected to the inlet of the second coal feeder 9, the outlet of the second coal feeder 9 is connected to the inlet of the low-temperature steam dryer 10, the outlet of the low-temperature steam dryer 10 is connected to the inlet of the third buffer chamber 11 via a belt conveyor, and the outlet of the third buffer chamber 11 is connected to a dry sorting device. Dust is generated during the transfer process after low-temperature steam drying. Due to collisions and drops during material transfer, dust may be converted into particulate matter and diffuse into the environment. Therefore, a closed environment is used for the transfer process, and cooling air is continuously introduced through a blower 35 to reduce the temperature of the dried material and prevent spontaneous combustion and dust explosions. Particle size distribution and moisture content can be obtained after sampling the coal powder in this stage.

[0029] The drying equipment in this embodiment employs a low-temperature steam rotary drying technology for coal slime, which is an indirect heat exchange technology using steam as a heat source. The low-temperature steam dryer indirectly contacts the moist coal material to evaporate the moisture, resulting in dry coal. This low-temperature steam rotary drying technology is a novel and environmentally friendly drying process. The steam temperature is approximately 90-150°C. The drying process involves only physical drying and mechanical extrusion, and no solid waste is generated during production, avoiding secondary pollution to the environment. The steam condensate can be collected and recycled for heating, achieving zero emissions. The low-temperature steam indirect dryer drum of the low-temperature steam drying device 10 has steam heating tubes arranged concentrically throughout the entire dryer. External steam first contacts the heating tubes, and indirect continuous drying is achieved through the heat from the heating tubes. The heating tubes rotate with the drum, and after the steam enters the steam chamber of the dryer, it is evenly distributed into each heating tube. Material with a certain moisture content is fed into the main body of the dryer from one end, and the movement direction of the material is opposite to that of the steam. Inside the rotating drum, the material is lifted and stirred by the heating tubes, exchanging heat with the heat exchange tubes while constantly moving. It is dried by the heat provided by the heating tubes and then moves from the feed port to the discharge port due to the tilt and continuous rotation of the drum. The evaporating moisture is drawn to the dust collector by an induced draft fan and then discharged. The low-temperature steam drying unit 10 mainly consists of a feeding system, a dryer, a product conveyor, a steam / water system, and a tail gas dust collector. The raw material is evenly fed to the feeding belt conveyor by a quantitative feeder, then enters the twin-shaft mixer, and finally enters the steam dryer via a mixing feeder. After the drying process is completed, the dried and shaped product is transported by a discharge belt conveyor to the product buffer silo via a collecting belt conveyor or directly to the under-silo belt conveyor.

[0030] In one embodiment, the dry separation equipment includes a third coal feeder 12, a 13mm / 6mm grading screen 15, and a dry separation device 16. The outlet of the drying equipment is connected to the inlet of the third coal feeder 12, and the outlet of the third coal feeder 12 is connected to the inlet of the 13mm / 6mm grading screen 15. The oversize outlet of the 13mm / 6mm grading screen 15 is connected to the belt conveyor at the inlet of the air-heavy medium fluidized bed separator. The undersize outlet of the 13mm / 6mm grading screen 15 is connected to the inlet of the dry separation device 16, and the outlet of the dry separation device 16 is connected to a second clean coal belt conveyor and a second gangue belt conveyor, respectively, to transport the separated clean coal and gangue separately. High-efficiency dry separation is a type of dry separation equipment that relies on the combined effects of vibration, wind, and media to achieve separation. Inside the dry separation device 16, the coal undergoes a spiral tumbling motion. Under the action of wind and vibration, the bed begins to loosen, and the material stratifies according to its density under the action of gravity. The biggest advantage of the dry sorting device 16 is that it requires no water, has low infrastructure investment, and low processing costs. It is particularly suitable for pre-discharge of raw coal with high gangue content, as well as for sorting and discharging gangue in raw coal when gangue is prone to mud formation. It is also suitable for coal sorting in arid, water-scarce, and cold regions. The dry sorting device 16 mainly includes a sorting bed, an air supply device, and a dust removal and purification device. Raw coal is transported to the feed inlet of the dry sorting device 16 by a feeder and enters the sorting bed with a certain longitudinal and transverse slope, forming a material bed layer of a certain thickness on the bed surface. High-density material contacts the bed surface and moves towards the back plate under the action of vibration inertial force. It is guided upward by the back plate and discharged at the tail end, becoming gangue. Low-density material slides down the bed surface under the action of gravity and passes through the discharge baffle, becoming clean coal product. Material between high-density and low-density becomes middlings.

[0031] In one embodiment, the air-heavy medium fluidized bed separation equipment includes a fourth buffer chamber 17, a fourth coal feeder 18, and an air-heavy medium fluidized bed separation device 19. The inlet of the fourth buffer chamber 17 is connected to a belt conveyor at the outlet of the 13mm / 6mm grading screen 15, the outlet of the fourth buffer chamber 17 is connected to the inlet of the fourth coal feeder 18, the outlet of the fourth coal feeder 18 is connected to the inlet of the air-heavy medium fluidized bed separation device 19, the outlet of the air-heavy medium fluidized bed separation device 19 is connected to a 2mm gangue desliming screen 21 and a 2mm clean coal desliming screen 22, respectively, the processing of the 2mm gangue desliming screen 21 is connected to a third gangue belt conveyor, and the outlet of the 2mm clean coal desliming screen 22 is connected to a third clean coal belt conveyor. Dust diffusion is more likely to occur in the high-efficiency dry separation stage and the air-heavy medium fluidized bed separation stage, therefore, the coal dust generated during the separation process of these stages is sampled and analyzed. The principle is as follows: when air at a certain pressure passes through an air distribution device with a pressure drop effect, it enters the fluidized bed stably and uniformly, causing the heavy medium in the fluidized bed to expand and form a fluidized gas-solid two-phase flow. The heavy medium consists of a mixture of pulverized coal and magnetite powder in a certain proportion. The material enters from the feed inlet above the fluidized bed, and the coal particles are subjected to forces in the fluidized bed, which conforms to Archimedes' theorem. Clean coal continuously floats to the top, while tailings ash continuously sinks, and is finally transported by a scraper conveyor to complete the coal washing process. The air-heavy medium fluidized bed separator 19 mainly consists of an upper chamber, a coal discharge end, a pressure chain block, a drive shaft, an air distribution device, a scraper conveyor, a gangue discharge end, an air chamber, and a tail shaft. Among these, the air distribution device and the scraper conveyor are key components of the coal preparation machine, affecting the uniformity and stability of air distribution and the continuity of coal separation. In this embodiment, the air-heavy medium fluidized bed separator 19 is equipped with a pressure gauge 20. The pressure gauge 20 can monitor the density and height in the air-heavy medium fluidized bed separator 19 in real time, and provide feedback and adjust the operating parameters of the air-heavy medium fluidized bed separator 19 to ensure that the density and height of the bed in the separator meet the separation requirements.

[0032] In one embodiment, the media recovery and purification equipment includes a diverter 23, a fifth buffer chamber 24, a fifth coal feeder 25, a sixth buffer chamber 26, a magnetic separator 28, a seventh buffer chamber 29, a seventh coal feeder 30, a 2mm gangue desliming screen 21, and a 2mm clean coal desliming screen 22. The inlet of the diverter 23 is connected to the belt conveyor at the outlet of the 2mm gangue desliming screen 21 and the belt conveyor at the outlet of the 2mm clean coal desliming screen 22, respectively. The outlet of the diverter 23 is connected to the inlet of the fifth buffer chamber 24 and the inlet of the sixth buffer chamber 26, respectively. The diverter 23 is composed of a housing, a diverting plate, a shaft, a crank, etc. The diverting plate is located in the middle of the housing, thus forming two channels for the material. The diverting plate is connected to the housing through the drive shafts at both ends and the sealing components. A crank is mounted on one end of the shaft, which can rotate the diverting plate in the housing through an electric actuator. The rotation angle of the diverting plate determines the opening of the two channels. The outlet of the fifth buffer chamber 24 is connected to the inlet of the fifth coal feeder 25, and the outlet of the fifth coal feeder 25 is connected to the media recovery inlet of the air-heavy medium fluidized bed separator 19. The outlet of the sixth buffer chamber 26 is connected to the inlet of the sixth coal feeder 27, and the outlet of the sixth coal feeder 27 is connected to the inlet of the magnetic separator 28. The outlet of the magnetic separator 28 is connected to the media replenishment chamber, and the outlet of the media replenishment chamber is connected to the inlet of the seventh buffer chamber 29. The outlet of the seventh buffer chamber 29 is connected to the inlet of the seventh coal feeder 30, and the outlet of the seventh coal feeder 30 is connected to the media recovery inlet of the air-heavy medium fluidized bed separator 19. After sampling the undersize materials of the 2mm gangue desliming screen 21 and the 2mm clean coal desliming screen 22, the distribution results of magnetic material content and coal powder particle size distribution in the coal powder can be obtained, which can be used to evaluate the separation effect of the air-heavy medium fluidized bed separator. The 2mm gangue desliming screen 21 and the 2mm clean coal desliming screen 22 operate on the same principle. Vibration forces classify the feed material, resulting in +2mm gangue or clean coal products on the upper screen and -2mm coal powder mixed with magnetite weighting medium in the lower screen. In actual operation, the -2mm coal powder and magnetite powder mixture enters the distributor 23 for further separation. A portion is sent to the magnetic separator 28 to remove non-magnetic materials, immediately yielding magnetic clean coal. The other portion of the weighting medium is directly fed into the air-heavy medium fluidized bed separator 19 for recycling, enabling control of the fluidized bed height and density within the separator.

[0033] In one embodiment, the induced draft dust removal equipment includes a first dust collector 13, a first induced draft fan 14, a second dust collector 31, a second induced draft fan 32, an air valve 33, an air receiver 34, and a blower 35. The inlet of the first dust collector 13 is connected to the dust removal pipeline of the drying equipment, and the outlet of the first dust collector 13 is connected to the inlet of the first induced draft fan 14. The outlet of the first induced draft fan 14 is connected to the outside environment to discharge qualified air. The inlet of the second dust collector 31 is connected to an X-ray sorting device, a dry sorting device, and an air-heavy medium fluidization device. The dust removal pipeline of the bed sorting equipment is connected, the outlet of the second dust collector 31 is connected to the inlet of the second induced draft fan 32, and the outlet of the second induced draft fan 32 is connected to the outside to discharge qualified air to the outside environment; the inlet of the blower 35 is connected to the outside, and the outlet of the blower 35 is connected to the air receiver 34. The air receiver 34 is connected to the air heavy medium fluidized bed sorting equipment through a pipeline equipped with an air valve 33; by taking multiple samples of the coal powder stored in the dust collector for testing, the representative physical and chemical properties of the coal powder in this process system can be obtained.

[0034] This invention also provides a method for monitoring, purifying, and recovering pulverized coal during the coal sorting process, comprising the following steps: Raw coal is screened to remove impurities and crushed to a particle size smaller than a set value. Dust samples are taken during the raw coal crushing process, then screened and analyzed to obtain the coal powder particle size classification. Materials with a particle size greater than 100mm in the raw coal are sorted by X-ray sorting equipment, and the sorted clean coal and gangue are transported to their respective storage locations. Materials with a particle size of less than 100mm in the raw coal are fed into the drying equipment for drying, and the particle size distribution and moisture content of the dried coal powder are sampled. After drying and sampling, the coal powder is sequentially fed into the dry separation equipment and the air-heavy medium fluidized bed separation equipment for separation. The separated clean coal and gangue are transported to the corresponding storage locations, and the coal powder generated during the separation process of the dry separation equipment and the air-heavy medium fluidized bed separation equipment is sampled and analyzed. After being separated by the air-heavy medium fluidized bed separator, the heavy medium is recovered and purified by the medium recovery and purification equipment, and then circulated back to the air-heavy medium fluidized bed separator. Samples are taken from the undersize materials of the 2mm gangue desliming screen 21 and the 2mm clean coal desliming screen 22 of the air-heavy medium fluidized bed separator to obtain the distribution results of magnetic material content and particle size distribution in the coal powder, thus indirectly evaluating the separation effect of the air-heavy medium fluidized bed separator. Yinfeng dust collectors were used to separate X-ray sorting equipment, drying equipment, dry sorting equipment, and air-heavy medium fluidized bed sorting equipment. Air with qualified dust concentration was discharged into the atmosphere. The coal powder stored in the dust collectors was sampled and tested multiple times to obtain the physical and chemical properties of the coal powder.

[0035] Example 1 This embodiment describes a full-size dry separation process, suitable for drying, dehydrating, and upgrading moist thermal coal. After pre-coal screening, crushing, and grading, the moist thermal coal to be separated yields 200-100mm and 100-0mm moist thermal coal, respectively. The 200-100mm moist thermal coal then enters an X-ray intelligent dry separation device, with the density of the clean coal product mainly concentrated at -1.4 g / cm³. 3 and +1.8g / cm 3 +1.8g / cm 3 The yield was approximately 18%, indicating that the refined coal product contained some gangue. The gangue density was entirely concentrated at +1.8 g / cm³. 3 This means that the coal content in the gangue product is extremely low. After X-ray intelligent dry separation, the calorific value of the clean coal product can reach 3286 kcal / kg. 100-0 mm moisture-containing thermal coal is dried at a low temperature with a processing capacity of 25 t / h and a steam inlet temperature of 129℃. The moisture content before drying is 12.26%, which is reduced to 7.79% after drying. After drying, 100-13 mm / 6 mm coal is separated by a vibration-airflow composite force field high-efficiency dry separation system to obtain 100-13 mm / 6 mm clean coal and 100-13 mm / 6 mm gangue products. The calorific value of the clean coal product before separation is 3948 kcal / kg, which is increased to 4329 kcal / kg after drying. 13-0mm / 6-0mm coal particles enter an air-heavy medium fluidized bed separation system to obtain 13-0mm / 6-0mm clean coal and 13-0mm / 6-0mm gangue. The calorific value of the clean coal product is 4679 kcal / kg. This process eliminates the coal slime generation stage, reducing the investment and operating costs of the coal slime water treatment system. The coal dust generated during the separation process can be purified and recovered through an induced draft dust removal system, and the magnetite powder weighting can be recycled through a magnetic separation system. This process is suitable for coal drying, dehydration, separation, and upgrading in arid and water-scarce areas of western China.

[0036] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A coal sorting process fly ash monitoring and clean recovery system, characterized in that: The application relates to a coal preparation system, which comprises: a pretreatment device capable of screening and removing impurities from raw coal and crushing the raw coal to a particle size less than a set value; an X-ray sorting device capable of sorting materials with a particle size greater than 100 mm in the raw coal; a drying device capable of receiving and drying raw coal with a particle size less than 100 mm; a dry sorting device capable of screening the dried raw coal to sort raw coal with a particle size between 100 mm and 13 mm; an air dense medium fluidized bed sorting device capable of receiving and screening raw coal with a particle size less than 13 mm screened by the dry sorting device; a medium recovery and purification device capable of recovering and recycling the weighting agent carried in the product sorted by the air dense medium fluidized bed sorting device; and an air induction and dust removal device capable of recovering dust generated by the X-ray sorting device, the drying device, the dry sorting device, the air dense medium fluidized bed sorting device and the medium recovery and purification device respectively, and discharging air with qualified dust concentration to the atmosphere. The pretreatment device comprises a 200 mm grading screen, an iron remover, a crusher and a 100 mm grading screen; the 200 mm grading screen is connected with a raw coal belt conveyor at an inlet, the 200 mm grading screen is connected with the iron remover on the screen and the crusher under the screen at an outlet respectively, the crusher is connected with a belt conveyor of the 100 mm grading screen, and an outlet on the screen of the 100 mm grading screen is connected with the X-ray sorting device, and an outlet under the screen of the 100 mm grading screen is connected with the drying device.

2. The coal beneficiation process dust monitoring and cleaning recovery system according to claim 1, characterized in that: The X-ray sorting device comprises a first buffer bin, a first coal feeder and an X-ray intelligent sorting device; the first buffer bin is connected with the outlet on the screen of the 100 mm grading screen at an inlet, the outlet of the first buffer bin is connected with the inlet of the first coal feeder, the outlet of the first coal feeder is connected with the inlet of the X-ray intelligent sorting device, and the outlet of the X-ray intelligent sorting device is connected with a first clean coal product belt conveyor and a first gangue product belt conveyor respectively to convey the sorted clean coal and gangue respectively.

3. The coal beneficiation process dust monitoring and cleaning recovery system of claim 2, wherein: The drying device comprises a second buffer bin, a second coal feeder, a low-temperature steam drying device and a third buffer bin; the second buffer bin is connected with the outlet under the screen of the 100 mm grading screen at an inlet, the outlet of the second buffer bin is connected with the inlet of the second coal feeder, the outlet of the second coal feeder is connected with the inlet of the low-temperature steam drying device, the outlet of the low-temperature steam drying device is connected with the inlet of the third buffer bin through a belt conveyor, and the outlet of the third buffer bin is connected with the dry sorting device.

4. The coal beneficiation process dust monitoring and cleaning recovery system of claim 2, wherein: ​ 5. The coal beneficiation process dust monitoring and cleaning recovery system of claim 1, wherein: The dry sorting device comprises a third coal feeder, a 13mm / 6mm grading screen and a dry sorting device; the outlet of the drying device is connected with the inlet of the third coal feeder, the outlet of the third coal feeder is connected with the inlet of the 13mm / 6mm grading screen, the outlet above the 13mm / 6mm grading screen is connected with the belt conveyor at the inlet of the air dense medium fluidized bed sorting device; the outlet below the 13mm / 6mm grading screen is connected with the inlet of the dry sorting device, and the outlet of the dry sorting device is connected with the second clean coal belt conveyor and the second gangue belt conveyor respectively to convey the sorted clean coal and gangue respectively.

6. The coal beneficiation process dust monitoring and cleaning recovery system of claim 5, wherein: The air dense medium fluidized bed sorting device comprises a fourth buffer bin, a fourth coal feeder and an air dense medium fluidized bed sorting device; the inlet of the fourth buffer bin is connected with the belt conveyor at the outlet above the 13mm / 6mm grading screen, the outlet of the fourth buffer bin is connected with the inlet of the fourth coal feeder, the outlet of the fourth coal feeder is connected with the inlet of the air dense medium fluidized bed sorting device, and the outlet of the air dense medium fluidized bed sorting device is connected with a 2mm gangue medium draining screen and a 2mm clean coal medium draining screen respectively, the 2mm gangue medium draining screen is connected with a third gangue belt conveyor, and the outlet of the 2mm clean coal medium draining screen is connected with a third clean coal belt conveyor.

7. The coal beneficiation process dust monitoring and cleaning recovery system of claim 6, wherein: The medium recycling and purifying device comprises a flow divider, a fifth buffer bin, a fifth coal feeder, a sixth buffer bin, a fifth coal feeder, a magnetic separator, a seventh buffer bin and a seventh coal feeder; the inlet of the flow divider is connected with the belt conveyor at the outlet of the 2mm gangue medium draining screen and the belt conveyor at the outlet of the 2mm clean coal medium draining screen respectively, the outlet of the flow divider is connected with the inlet of the fifth buffer bin and the inlet of the sixth buffer bin respectively, the outlet of the fifth buffer bin is connected with the inlet of the fifth coal feeder, the outlet of the fifth coal feeder is connected with the medium recycling inlet of the air dense medium fluidized bed sorting device, the outlet of the sixth buffer bin is connected with the inlet of the sixth coal feeder, the outlet of the sixth coal feeder is connected with the inlet of the magnetic separator, the outlet of the magnetic separator is connected with a medium supplement bin, the outlet of the medium supplement bin is connected with the inlet of the seventh buffer bin, the outlet of the seventh buffer bin is connected with the inlet of the seventh coal feeder, and the outlet of the seventh coal feeder is connected with the medium recycling inlet of the air dense medium fluidized bed sorting device.

8. The coal beneficiation process dust monitoring and cleaning recovery system of claim 1, wherein: The air-entraining dust removal equipment comprises a first dust remover, a first air-entraining fan, a second dust remover, a second air-entraining fan, an air valve, an air bag and a blower; the inlet of the first dust remover is connected with a dust removal pipeline of the drying equipment, the outlet of the first dust remover is connected with the inlet of the first air-entraining fan, the outlet of the first air-entraining fan is connected with the outside, so as to discharge qualified air to the outside environment; the inlets of the second dust remover are respectively connected with dust removal pipelines of the X-ray sorting equipment, the dry sorting equipment and the air dense medium fluidized bed sorting equipment, the outlet of the second dust remover is connected with the inlet of the second air-entraining fan, the outlet of the second air-entraining fan is connected with the outside, so as to discharge qualified air to the outside environment; the inlet of the blower is connected with the outside, the outlet of the blower is connected with the air bag, and the air bag is connected with the air dense medium fluidized bed sorting equipment through a pipeline provided with an air valve.

9. The coal beneficiation process dust monitoring and cleaning recovery system of claim 6, wherein: The air dense medium fluidized bed sorting device is provided with a pressure gauge, which can monitor the density and height of the air dense medium fluidized bed sorting device in real time, and feed back and adjust the operating parameters of the air dense medium fluidized bed sorting device.

10. A coal sorting process fly ash monitoring and clean recovery method, characterized in that: The method comprises the following steps: The raw coal is screened and impurities are removed, and is crushed to a particle size less than a set value. After dust sampling during the raw coal crushing process, screening and testing are performed to obtain the coal powder particle size classification; the material with a particle size greater than 100 mm in the raw coal enters the X-ray sorting equipment for sorting, and the sorted clean coal and gangue are respectively transported to the corresponding storage positions; The material with a particle size less than 100 mm in the raw coal enters the drying equipment for drying, and the particle size distribution and moisture content of the sampled dried coal powder are obtained; The dried and sampled coal powder enters the dry sorting equipment and the air dense medium fluidized bed sorting equipment in sequence for sorting, and the sorted clean coal and gangue are respectively transported to the corresponding storage positions, and the coal powder generated during the sorting process of the dry sorting equipment and the air dense medium fluidized bed sorting equipment is respectively sampled and tested and analyzed; The heavy medium after sorting of the air dense medium fluidized bed sorting equipment is recycled and purified by a medium recycling and purification equipment, and then is circulated into the air dense medium fluidized bed sorting equipment. The undersize materials of the 2 mm gangue and 2 mm clean coal screens of the air dense medium fluidized bed sorting equipment are respectively sampled to obtain the magnetic material content distribution results and the coal powder particle size distribution results of the coal powder, so as to evaluate the air dense medium fluidized bed sorting effect The dust of the X-ray sorting equipment, the drying equipment, the dry sorting equipment and the air dense medium fluidized bed sorting equipment is respectively removed, and the dust with a qualified concentration is discharged to the atmosphere. The coal powder stored in the dust remover is sampled and tested multiple times to obtain the physical and chemical property results of the coal powder.

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