Low-quality coal high-precision dry-method deashing and upgrading method and process

Abstract

The invention relates to the technical field of pulverized coal processing, in particular to a low-quality coal high-precision dry-method deashing and upgrading method and process, and the method comprises the following process steps: S1, conveying and pretreatment; s2, vibrating and blowing; s3, primary screening; s4, screening for the second time; s5, dewatering and drying; s6, monitoring, regulating and controlling; and S7, collection and recovery. Comprising a shell and a spiral feeder, two vibration motors are symmetrically installed on the shell, two damping bases are symmetrically installed at the bottom end of the shell, the device further comprises a pretreatment mechanism, and the pretreatment mechanism is arranged on the shell and the spiral feeder. According to the device, coal powder can be preheated and preliminarily crushed and separated, so that preparation is made for the subsequent dewatering and drying process, the coal powder can be promoted to be subjected to secondary crushing and separation in the subsequent flowing and drying process, and unqualified coal powder and dust in the coal powder are separated, discharged and recycled; therefore, the overall quality of pulverized coal drying and deashing is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pulverized coal processing, and in particular to a method and process for high-precision dry deashing and quality improvement of low-quality coal. Background Art

[0002] Compared with common bituminous coal or anthracite, low-quality coal has obvious price advantages, but it has the characteristics of high impurity content, high moisture content and low calorific value. These characteristics not only limit the direct application scope of low-quality coal, but may also significantly reduce the combustion efficiency during the combustion process, resulting in energy waste. Therefore, before using low-quality coal, it must undergo a drying and deashing process to improve its quality. In the process of improving the quality of low-quality coal, drying and deashing are inseparable. The existing high-precision deashing methods for low-quality coal are mostly dry deashing, and dry deashing mainly separates the coal particles that were originally aggregated together through the vibration of the fluidized bed, and dries the coal through a fan. Then, through the blowing of the wind in the fan and the vibration of the fluidized bed, the impurities and dust in the dried low-quality coal are blown away, thereby completing the quality improvement of the low-quality coal.

[0003] However, when existing fluidized beds are used to dry and deash low-quality coal, most of them only crush and separate the coal particles in the low-quality coal by simple vibration, and the separation effect is not good. Some larger coal block agglomerates are difficult to be completely separated, which makes it difficult to fully dry the moisture inside the agglomerates, thereby reducing the quality of dehydration and drying. In addition, due to the existence of agglomerates, impurities in the low-quality coal are easily wrapped therein, and the dust therein may also adhere to the moisture inside it, thereby reducing the overall quality of drying and deashing, and thus greatly reducing the quality of the low-quality coal improvement, and the practicality is not good. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the fluidized bed in the prior art has poor separation effect when drying and deashing low-quality coal, thereby reducing the overall quality of drying and deashing of low-quality coal, and to propose a high-precision dry deashing and quality improvement method and process for low-quality coal.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A high-precision dry deashing and quality-improving process for low-quality coal includes the following process steps: S1, transporting and pretreatment, transporting the heated magnetic powder and the lignite pulverized coal to be processed into the stirring chamber, and preheating and initially crushing and separating the pulverized coal by the heated magnetic powder and the rotating stirring rod; S2. Vibration and blowing: After the pretreatment of the pulverized coal is completed, the solenoid valve is opened, and the magnetic powder and the pulverized coal fall onto the first sieve plate. The vibration motor is started to vibrate the outer shell, and the hot air blower and the blower are started to blow air into the outer shell. At the same time, the second motor is started to rotate the drum. S3. Primary screening: Control the first motor to make the first brush head move reciprocally. The vibration of the outer shell can screen the pulverized coal, so that the pulverized coal with too large particles remains on the first sieve plate, and the magnetic powder and the remaining pulverized coal fall onto the second sieve plate. The first brush head cooperates with the vibration of the outer shell to accelerate the screening of the pulverized coal. S4. Secondary screening: The reciprocating movement of the first brush head drives the reciprocating movement of the second brush head, so that the magnetic powder and the remaining pulverized coal on the second sieve plate are evenly distributed, and under the vibration of the outer shell, the pulverized coal with too small particles and part of the dust in the pulverized coal fall onto the mounting plate, and the remaining dust is lifted to form dust. S5. Dehydration and drying: The waste materials on the first sieve plate and the mounting plate and the materials on the second sieve plate move towards the recovery box and the aggregate box under the vibration of the outer shell, and cooperate with the drum, the first magnet and the second magnet, as well as hot air and cold air to complete the dehydration and drying of the pulverized coal. S6. Monitoring and regulation: During the above-mentioned moving process, if the thermal imaging probe monitors that the pulverized coal agglomerates, the energized electromagnet attracts the magnetic powder to break up the agglomerated pulverized coal. If the thermal imaging probe monitors that the pulverized coal is unevenly distributed, adjust the rotation speed and direction of the drum to disperse the pulverized coal from the thicker area to the thinner area. S7. Collection and recovery: The dried and deashed pulverized coal falls into the aggregate box, the magnetic powder is adsorbed by the magnetic rotating roller, the waste materials on the first sieve plate and the mounting plate respectively fall into the two recovery boxes, and the dust is discharged through the air outlet pipe and enters the bag filter after passing through the cyclone separation system.

[0006] A high-precision dry ash removal and quality improvement method for low-quality coal is applied to the above-mentioned process and uses the following device, including an outer shell and a screw feeder. Two vibration motors are symmetrically installed on the outer shell, and two shock-absorbing bases are symmetrically installed at the bottom of the outer shell. It also includes: A pretreatment mechanism is arranged on the outer shell and the screw feeder and is used to add heated magnetic powder into the pulverized coal in the screw feeder and perform preliminary crushing, separation and drying. A screening and drying mechanism is arranged inside the outer shell and is used to perform secondary crushing, separation and drying on the pulverized coal entering the outer shell. A waste material recovery mechanism and a collection mechanism are both arranged on the outer shell. The waste material recovery mechanism is used to recover the impurities and dust in the pulverized coal in the outer shell, and the collection mechanism is used to collect the dried and deashed pulverized coal.

[0007] Compared with the existing technology, the advantages of the present invention are: 1. Through the mutual cooperation of the pretreatment mechanism, the screening and drying mechanism, the waste recycling mechanism, and the collection mechanism, the present invention can not only preheat and preliminarily crush and separate the pulverized coal by using the mixing of the heated magnetic powder and the pulverized coal to be processed and the rotation of the stirring rod, so as to prepare for the subsequent dehydration and drying process, but also utilize the vibration of the outer shell, the wind blown by the hot air blower and the blower, the screening of the first sieve plate and the second sieve plate, the magnetic setting of the drum, and the impact of the magnetic powder to cause secondary crushing and separation of the pulverized coal during the subsequent flow drying process, and separate, discharge, and recycle the unqualified pulverized coal and dust in the pulverized coal, thereby effectively improving the overall quality of the drying and ash removal of the pulverized coal.

[0008] 2. Through the setting of the auxiliary component, by using the counterclockwise rotation of the drum and the setting of the balls in the air holes thereon, the present invention can drive the pulverized coal to rotate counterclockwise in the air. This rotation not only increases the residence time of the pulverized coal in the air, but also enables the pulverized coal to contact the hot air more fully, thereby improving the efficiency of dehydrating and drying the pulverized coal. And by using the clockwise rotation of the spiral fan blades in the drum, the hot air entering the hot air drum can form a turbulent flow at the spiral fan blades and act on the pulverized coal through the air holes, thereby ensuring that the hot air can contact the pulverized coal more evenly. When the hot air passes through the air holes on the drum, it will encounter the obstruction and perturbation of the balls. This obstruction and perturbation will enhance the turbulent effect of the hot air, enabling the hot air to mix with the pulverized coal more fully, thereby improving the quality of dehydrating and drying the pulverized coal.

[0009] 3. Through the setting of the screening control component, by using the reciprocating movement of the first brush head and the second brush head, the present invention can cooperate with the vibration of the outer shell to accelerate the screening of the pulverized coal by the first sieve plate, and at the same time, can control the thickness of the pulverized coal and magnetic powder falling on the second sieve plate and make it more uniform, thereby ensuring that the pulverized coal can be evenly affected by heat, and further effectively improving the efficiency and quality of dehydrating and drying the pulverized coal.

[0010] 4. Through the setting of the anti-overflow component, the present invention can utilize the suction of the first magnet and the repulsion of the second magnet to make the magnetic powder circulate up and down during the flow drying process, so as to make the magnetic powder squeeze and disperse the agglomerated pulverized coal and improve the flow state of the pulverized coal, and further improve the quality of dehydrating and drying the pulverized coal. And it can prevent the magnetic powder from overflowing the treatment area under the vibration of the outer shell, the blowing of the wind, and the magnetic action of the drum and the first magnet, thereby effectively ensuring the quality of dehydrating and drying the pulverized coal.

[0011] 5. Through the setting of the efficiency enhancement component, when the thermal imaging probe detects that the pulverized coal is caking, the electromagnet at the corresponding position is energized to attract the magnetic powder to move towards the caking pulverized coal, thereby dispersing the caking pulverized coal at that place and increasing the heat transfer efficiency of the pulverized coal at that place. When the thermal imaging probe detects uneven distribution of the pulverized coal, the second motor is controlled to adjust the rotation speed and direction of the roller at the corresponding position, and the pulverized coal is dispersed from the area with a thicker accumulation to the area with a thinner accumulation, thereby effectively ensuring the efficiency and quality of the dehydration and drying of the pulverized coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of the overall structure of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 2 is a top view of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 3 is a side view of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 4 is a full-sectional side view of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 5 is a schematic diagram of the full-sectional structure of the mixing chamber of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 6 is a full-sectional front view of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 7 is a bottom view of the first sieve plate of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 8 is a schematic diagram of the full-sectional structure of the second sieve plate of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 9 is a schematic diagram of the full-sectional structure of the roller of a high-precision dry ash removal and quality improvement method for low-quality coal proposed by the present invention; Figure 10 is Figure 9 a detailed enlarged view of part A; Figure 11 is Figure 9 a detailed enlarged view of part B.

[0013] In the figure: 1. Outer shell; 2. Feed inlet; 3. Screw feeder; 4. Hot air blower; 5. Air outlet pipe; 6. Cyclone separation system; 7. Bag filter; 8. Stirring chamber; 9. First motor; 10. Second motor; 11. Vibration motor; 12. Shock-absorbing base; 13. First discharge pipe; 14. Second discharge pipe; 15. Third discharge pipe; 16. Magnetic rotating roller; 17. Blower; 18. Recycling box; 19. Screw rod; 20. Connecting plate; 21. Fixed rod; 22. First brush head; 23. Second brush head; 24. First sieve plate; 25. Thermal imaging probe; 26. First magnet; 27. Second magnet; 28. Second sieve plate; 29. Electromagnet; 30. Mounting plate; 31. Feed pipe; 32. Third motor; 33. Stirring rod; 34. Feed tube; 35. Drum; 36. Rotating rod; 37. Spiral fan blade; 38. Internal gear ring; 39. First gear; 40. Second gear; 41. Ball. Detailed implementation manners

[0014] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0015] Refer to Figures 1 to 11 , a high-precision dry ash removal and quality improvement process for low-quality coal, including the following process steps: S1. Transportation and pretreatment: The heated magnetic powder and the lignite pulverized coal to be processed are transported into the stirring chamber 8, and the pulverized coal is preheated and preliminarily separated by the heated magnetic powder during the transportation. After entering the stirring chamber 8, the rotating stirring rod 33 is used to crush the pulverized coal; S2. Vibration and blowing: After the pretreatment of the pulverized coal is completed, the solenoid valve is opened, and the magnetic powder and the pulverized coal fall onto the first sieve plate 24. The vibration motor 11 is started to vibrate the outer shell 1, and the hot air blower 4 and the blower 17 are started to blow air from bottom to top towards the second sieve plate 28. At the same time, the second motor 10 is started to make the drum 35 rotate counterclockwise; S3. Primary screening: The first motor 9 is controlled to make the first brush head 22 reciprocate. The vibration of the outer shell 1 can screen the pulverized coal, so that the pulverized coal with too large particles remains on the first sieve plate 24, and the magnetic powder and the remaining pulverized coal fall onto the second sieve plate 28. The reciprocating movement of the first brush head 22 in cooperation with the vibration of the outer shell 1 can accelerate the screening of the pulverized coal; S4. Secondary screening: The reciprocating movement of the first brush head 22 drives the reciprocating movement of the second brush head 23. The magnetic powder and the remaining pulverized coal on the second sieve plate 28 are evenly distributed under the action of the second brush head 23, and under the vibration of the outer shell 1, the pulverized coal with too small particles and part of the dust in the pulverized coal fall onto the mounting plate 30, and the remaining dust is lifted to form dust; S5. Dehydration and drying: The waste on the first sieve plate 24 and the mounting plate 30, as well as the magnetic powder and pulverized coal on the second sieve plate 28, move towards the recovery box 18 and the aggregate box under the vibration of the outer shell 1, and cooperate with the roller 35, the first magnet 26, the second magnet 27, hot air and cold air during the movement and vibration to complete the effective dehydration and drying of the pulverized coal. S6. Monitoring and regulation: During the movement of the magnetic powder and pulverized coal on the second sieve plate 28, if the thermal imaging probe 25 detects that the pulverized coal is caking, the energized electromagnet 29 attracts the magnetic powder to break up the caked pulverized coal. If the thermal imaging probe 25 detects uneven distribution of pulverized coal in some areas, the rotation speed and direction of the roller 35 are adjusted to disperse the pulverized coal from the thicker area to the thinner area. S7. Collection and recovery: The dried and deashed pulverized coal on the second sieve plate 28 falls into the aggregate box, the magnetic powder is adsorbed by the rotating magnetic roller 16, the waste on the first sieve plate 24 and the mounting plate 30 respectively fall into the two recovery boxes 18, and the dust in the outer shell 1 is discharged through the air outlet pipe 5 and enters the bag filter 7 after passing through the cyclone separation system 6.

[0016] Refer to Figures 1 to 5 A high-precision dry ash removal and quality improvement method for low-quality coal is applied to the above process and uses the following device, including an outer shell 1 and a screw feeder 3. The screw feeder 3 is used to convey the pulverized coal to be processed into the outer shell 1. Two vibration motors 11 are symmetrically installed on the outer shell 1, and two shock-absorbing bases 12 are symmetrically installed at the bottom end of the outer shell 1. A pretreatment mechanism is provided on the outer shell 1 and the screw feeder 3 for adding heated magnetic powder into the pulverized coal in the screw feeder 3 and performing preliminary crushing, separation and drying. The screw feeder 3 is a prior art, and its specific structural design will not be described in detail here. The pretreatment mechanism includes a feed inlet 2 and a mixing chamber 8. The feed inlet 2 is installed on the screw feeder 3 and is connected to the input end of the screw feeder 3. The bottom end of the mixing chamber 8 is installed with a feed pipe 34, and the mixing chamber 8 is fixedly connected to the inside of the outer shell 1 through the feed pipe 34. An electromagnetic valve is installed in the feed pipe 34. The electromagnetic valve is a prior art and is not shown in the figure, and its specific structural design will not be described in detail here. The top end of the mixing chamber 8 is installed with a conveying pipe 31, and the mixing chamber 8 is connected to the output end of the screw feeder 3 through the conveying pipe 31. The mixing chamber 8 is located at the top end of the outer shell 1 near the edge, and a third motor 32 is installed at the top end of the mixing chamber 8. The output end of the third motor 32 penetrates the top wall of the mixing chamber 8 and is fixedly connected to a mixing rod 33.

[0017] Refer to Figures 1 to 6, a screening and drying mechanism is arranged inside the outer shell 1 for secondary crushing, separation and drying of the pulverized coal entering the outer shell 1. The screening and drying mechanism includes a first sieve plate 24, a second sieve plate 28 and a mounting plate 30. The first sieve plate 24, the second sieve plate 28 and the mounting plate 30 are sequentially installed inside the outer shell 1 from top to bottom, and are all inclined in a direction away from the screw feeder 3. The inclination angle of the second sieve plate 28 is smaller than that of the first sieve plate 24 and the mounting plate 30. The diameter of the sieve holes on the first sieve plate 24 is larger than that of the sieve holes on the second sieve plate 28. A blowing component is arranged on the outer shell 1 for blowing hot and cold air into the outer shell 1. The blowing component includes a hot air blower 4 and a blower 17. The hot air blower 4 and the blower 17 are both arranged on the ground, and the output ends of the hot air blower 4 and the blower 17 both penetrate through the side wall of the outer shell 1 and are arranged upward. The hot air blower 4 and the blower 17 are both located between the second sieve plate 28 and the mounting plate 30. The position of the blower 17 is close to one end of the outer shell 1 away from the screw feeder 3, and the hot air blower 4 is located between the screw feeder 3 and the blower 17.

[0018] Refer to Figures 1 to 11 , an auxiliary component is arranged on the second sieve plate 28 for improving the separation and drying effect of the pulverized coal. The auxiliary component includes two extension plates and a plurality of rollers 35. The two extension plates are respectively installed at the bottom of the second sieve plate 28 near the two side edges. The outer wall of the extension plate is in contact with the inner wall of the outer shell 1. The plurality of rollers 35 are evenly rotatably connected to the two extension plates. A plurality of second motors 10 are evenly installed on the outer wall of the outer shell 1. The output ends of the plurality of second motors 10 all penetrate through the outer shell 1 and the outer wall of one of the extension plates in sequence, and are respectively fixedly connected to the plurality of rollers 35. A plurality of through grooves corresponding to the plurality of rollers 35 are provided through the top of the second sieve plate 28. The part above the roller 35 is located in the through groove. The roller 35 is made of a magnetic material, and the magnetism of the roller 35 is the same as that of the magnetic powder. A plurality of air holes are evenly penetrated through the outer wall of the roller 35. A ball 41 is rotatably connected in the air hole. Two opposite inner walls of the roller 35 are rotatably connected with a rotating rod 36. A plurality of spiral fan blades 37 are evenly installed on the rotating rod 36. And a second gear 40 is installed on the outer wall of the rotating rod 36 near one end edge. An internal tooth ring 38 is installed on the inner wall of the roller 35. A first gear 39 is rotatably connected to one of the inner walls of the rotating rod 36. The internal tooth ring 38 and the second gear 40 are both meshed with the first gear 39.

[0019] Refer to Figures 1 to 4, a screening and regulation component is provided on the outer shell 1 for accelerating the screening speed of pulverized coal and magnetic powder on the first sieve plate 24 and regulating the thickness of pulverized coal and magnetic powder on the second sieve plate 28. The screening and regulation component includes a mounting frame which is fixedly installed at one end of the outer shell 1 close to the screw feeder 3. A fixing rod 21 is fixedly installed inside the mounting frame. A first motor 9 is installed on the outer wall of the mounting frame. A connecting plate 20 is slidably connected to the fixing rod 21. The output end of the first motor 9 penetrates through the outer wall of the mounting frame and is fixedly connected to a lead screw 19. The end of the lead screw 19 away from the first motor 9 is rotatably connected to the inner wall of the mounting frame, and the lead screw 19 is threadedly connected to the connecting plate 20. Two sliding rods are installed on the side of the connecting plate 20 facing the outer shell 1. Two chutes for the two sliding rods to slide through are respectively provided through one end of the outer shell 1. The ends of the two sliding rods away from the connecting plate 20 respectively pass through the two chutes and are respectively fixedly connected to a first brush head 22 and a second brush head 23. The bristles on the first brush head 22 are in contact with the top end of the first sieve plate 24. The second brush head 23 is located between the first sieve plate 24 and the second sieve plate 28, and there is a gap between the bristles on the second brush head 23 and the second sieve plate 28.

[0020] Refer to Figures 4 to 7 , an anti-overflow component is provided at the bottom end of the first sieve plate 24 for preventing the magnetic powder on the second sieve plate 28 from overflowing the area between the first sieve plate 24 and the second sieve plate 28. The anti-overflow component includes a plurality of first magnets 26 and a plurality of second magnets 27. The plurality of first magnets 26 and the plurality of second magnets 27 are both installed at the bottom end of the first sieve plate 24 and are arranged alternately. The magnetism of the first magnet 26 is opposite to that of the magnetic powder, and the magnetism of the second magnet 27 is the same as that of the magnetic powder. An efficiency enhancement component is provided inside the outer shell 1 for more effectively separating the caked pulverized coal on the second sieve plate 28. The efficiency enhancement component includes a plurality of thermal imaging probes 25 and a plurality of electromagnets 29. The plurality of thermal imaging probes 25 are evenly installed at the bottom end of the first sieve plate 24, and the positions of the plurality of thermal imaging probes 25 are respectively located on the non-opposite sides of each adjacent first magnet 26 and second magnet 27. The plurality of electromagnets 29 are evenly and fixedly embedded on two opposite inner side walls of the outer shell 1, and the bottom positions of the plurality of electromagnets 29 correspond to the top position of the second sieve plate 28.

[0021] Refer to Figures 1 to 4, a waste recycling mechanism and a collection mechanism are provided on the outer shell 1. The waste recycling mechanism is used to recycle impurities and dust in the pulverized coal in the outer shell 1, and the collection mechanism is used to collect the pulverized coal after drying and ash removal. The waste recycling mechanism includes a cyclone separation system 6, a bag filter 7 and two recycling bins 18. The cyclone separation system 6, the bag filter 7 and the two recycling bins 18 are all arranged on the ground. The output end of the cyclone separation system 6 is connected to the input end of the bag filter 7, and an air outlet pipe 5 is installed at the input end of the cyclone separation system 6. The cyclone separation system 6 is connected to the inside of the outer shell 1 through the air outlet pipe 5. The air outlet pipe 5 is located at the top of the outer shell 1. One end of the outer shell 1 away from the screw feeder 3 is fixedly connected with a first discharge pipe 13 and a third discharge pipe 15. The positions of the connections of the first discharge pipe 13 and the third discharge pipe 15 with the outer shell 1 correspond to the positions of the first sieve plate 24 and the mounting plate 30 respectively, and the positions of the bottom openings of the first discharge pipe 13 and the third discharge pipe 15 correspond to the positions of the two recycling bins 18 respectively. The cyclone separation system 6 and the bag filter 7 are both prior arts, and their specific structural designs will not be elaborated here.

[0022] Refer to Figure 1 , Figure 3 and Figure 4 , the collection mechanism includes a second discharge pipe 14, an aggregate bin and two mounting platforms. The aggregate bin and the two mounting platforms are both arranged on the ground. The second discharge pipe 14 is fixedly connected to one end of the outer shell 1 away from the screw feeder 3, and the position of the connection of the second discharge pipe 14 and the outer shell 1 corresponds to the position of the second sieve plate 28. The position of the bottom opening of the second discharge pipe 14 corresponds to the position of the aggregate bin. The two mounting platforms are located at both ends of the aggregate bin, and a magnetic rotating roller 16 is rotatably connected to the two mounting platforms together. A driving part for driving the magnetic rotating roller 16 to rotate is installed on one of the mounting platforms. The driving part is a prior art, and its specific structural design will not be elaborated here. The magnetic rotating roller 16 is located between the second discharge pipe 14 and the aggregate bin, and the magnetic rotating roller 16 is located obliquely below the bottom opening of the second discharge pipe 14. The magnetism of the magnetic rotating roller 16 is opposite to the magnetism of the magnetic powder.

[0023] The present invention is applied to the drying and deashing of lignite pulverized coal with high water content. First, the lignite pulverized coal to be processed is added into the screw feeder 3, and the heated magnetic powder is poured into the screw feeder 3 from the feed inlet 2. Together with the lignite pulverized coal to be processed, it is transported to the mixing chamber 8 through the screw feeder 3. During this transportation process, the heated magnetic powder can transfer heat to the lignite pulverized coal to preheat the pulverized coal and prepare for the subsequent dehydration and drying process. At the same time, the magnetic powder can also impact the lignite pulverized coal during transportation, which helps to break the adhesion and agglomeration between the lignite pulverized coal particles and improve its fluidity. Subsequently, the mixture of lignite pulverized coal and magnetic powder enters the mixing chamber 8 through the conveying pipe 31. At this time, the third motor 32 is started to make the stirring rod 33 start to rotate, and the mixture of lignite pulverized coal and magnetic powder is initially broken. Under the combined action of the impact of the magnetic powder on the lignite pulverized coal and the crushing of the stirring rod 33, the pre-separation of the lignite pulverized coal is achieved, thereby improving the efficiency and quality of the subsequent drying.

[0024] After the preheating and pre-separation of the lignite pulverized coal are completed, the solenoid valve is opened, and the magnetic powder and the lignite pulverized coal will fall onto the first sieve plate 24 through the feed pipe 34. At this time, the vibration motor 11 is started to vibrate the housing 1, and the hot air blower 4 and the blower 17 are started to blow hot air and cold air into the housing 1. At this time, the hot air and cold air are blown upward in the direction of the second sieve plate 28. The vibration of the housing 1 can separate the lignite pulverized coal that is not completely separated or agglomerated again on the first sieve plate 24 and screen it by the first sieve plate 24. Since the diameter of the sieve holes on the first sieve plate 24 is larger than the diameter of the sieve holes on the second sieve plate 28, the lignite pulverized coal with too large particles remains on the first sieve plate 24, and the magnetic powder and the remaining lignite pulverized coal fall onto the second sieve plate 28. Under the vibration of the housing 1, the lignite pulverized coal with too small particles on the second sieve plate 28 and some extremely fine dust in the lignite pulverized coal fall onto the mounting plate 30, and the remaining dust will be lifted and form dust. These dusts will be carried by the airflow blown by the hot air blower 4 and the blower 17 and then discharged through the air outlet pipe 5.

[0025] Since the first sieve plate 24, the second sieve plate 28, and the mounting plate 30 are all inclined towards the recovery box 18 and the aggregate box (i.e., inclined towards the end of the device), therefore, the waste materials on the first sieve plate 24 and the mounting plate 30 and the materials on the second sieve plate 28 will start to flow under the vibration of the housing 1, and the materials on the second sieve plate 28 will be blown by the hot air and cold air during the flowing process. Since the inclination angles of the first sieve plate 24 and the mounting plate 30 are larger than that of the second sieve plate 28, the waste materials on the first sieve plate 24 and the mounting plate 30 will flow to the end of the device more quickly compared to the materials on the second sieve plate 28. As a result, the hot air and cold air blown upward from the bottom will not be blocked by the waste materials on the first sieve plate 24, ensuring the air circulation inside the housing 1 and enabling the dust inside the housing 1 to be smoothly discharged along the airflow through the air outlet pipe 5.

[0026] Meanwhile, start multiple second motors 10 to make multiple drums 35 start to rotate counterclockwise. While the drums 35 are rotating, control the first motor 9 to make the lead screw 19 rotate, thereby driving the first brush head 22 and the second brush head 23 to move. Subsequently, control the first motor 9 to reverse, so that the first brush head 22 and the second brush head 23 achieve reciprocating movement. Since the bristles on the first brush head 22 are in contact with the top of the first sieve plate 24, therefore, the reciprocating movement of the first brush head 22 in cooperation with the vibration of the housing 1 can accelerate the screening of the separated lignite pulverized coal by the first sieve plate 24, enabling the magnetic powder and the lignite pulverized coal to fall on the second sieve plate 28 faster. Since the position of the blower 17 is close to one end of the housing 1 away from the screw feeder 3, and the hot air blower 4 is located between the screw feeder 3 and the blower 17, when the hot air and the cold air blow to the second sieve plate 28, the hot air will first dry the lignite pulverized coal, and the cold air will cool the dried lignite pulverized coal. When the hot air enters from the bottom and passes through the lignite pulverized coal, its blowing force on the lignite pulverized coal will cooperate with the vibration of the housing 1 to make the lignite pulverized coal continuously tumble and jump on the second sieve plate 28, finally forming a fluidized state similar to a liquid, ensuring that the lignite pulverized coal can be evenly affected by the heat and avoiding problems such as local overheating or uneven drying.

[0027] At the same time, since there is a gap between the bristles on the second brush head 23 and the second sieve plate 28, therefore, the reciprocating movement of the second brush head 23 can flatten the lignite pulverized coal and the magnetic powder falling on the second sieve plate 28, that is, it can control the thickness of the lignite pulverized coal and the magnetic powder falling on the second sieve plate 28 and make it more uniform, so that the lignite pulverized coal and the magnetic powder can flow more evenly when the second sieve plate 28 vibrates, and further ensure that the lignite pulverized coal can be evenly affected by the heat, effectively improving the quality of dehydration drying of the lignite pulverized coal. In addition, since the magnetic powder can fill the gaps between the lignite pulverized coal and has a high thermal conductivity, the magnetic powder can increase the effective contact area between the whole lignite pulverized coal and the hot air. This effect of increasing the contact area, combined with the excellent thermal conductivity of the magnetic powder itself, can significantly improve the heat transfer efficiency, ensure that the lignite pulverized coal can be heated more evenly and efficiently, and thus improve the efficiency and quality of dehydration drying of the lignite pulverized coal.

[0028] When the lignite pulverized coal and the magnetic powder flow to the position of the drum 35 on the second sieve plate 28, the rotating drum 35 will drive the lignite pulverized coal to rotate counterclockwise in the air through the frictional force on its surface (the magnetic powder is also moving synchronously at this time). This rotation not only increases the residence time of the lignite pulverized coal in the air, but also makes the movement path of the lignite pulverized coal more complex, so as to obtain a longer drying time on the same path, effectively improving the dehydration drying efficiency of the lignite pulverized coal. Since the drum 35 is made of a magnetic material and its magnetism is the same as that of the magnetic powder, the rotating drum 35 will exert a repulsive force on the magnetic powder, making the movement of the magnetic powder more intense. The intense movement of the magnetic powder can continuously impact the lignite pulverized coal in contact with it. At the same time, because the magnetic powder usually has a smaller particle size and high hardness, it can generate enough impact force when hitting the lignite pulverized coal to break the caked lignite pulverized coal, but will not excessively wear the lignite pulverized coal, thus effectively breaking up the caked lignite pulverized coal into smaller particles, which is more conducive to the dehydration drying of the lignite pulverized coal and the separation of dust on it. When the drum 35 rotates, under the combined action of the internal gear ring 38, the first gear 39 and the second gear 40, the rotating rod 36 inside it will rotate clockwise, so that the spiral fan blade 37 rotates clockwise. The opposite rotation directions of the drum 35 and the spiral fan blade 37 can cause the hot air entering the hot air drum 35 to form a turbulent flow at the spiral fan blade 37, and finally act on the lignite pulverized coal through the air holes on the surface of the drum 35, ensuring that the hot air can contact the lignite pulverized coal more evenly, and thus improving the heat uniformity of the lignite pulverized coal.

[0029] In addition, when the drum 35 rotates, the balls 41 in the air holes on it will also roll accordingly, which can more effectively push the lignite pulverized coal and make the lignite pulverized coal rotate, so that it can contact the hot air more fully. When the hot air passes through the air holes of the drum 35, it will encounter the obstruction and disturbance of the balls 41. This obstruction and disturbance will enhance the turbulent flow effect of the hot air, making the hot air mix with the lignite pulverized coal more fully, thus further improving the quality of the dehydration drying of the lignite pulverized coal.

[0030] Since the magnetism of the first magnet 26 is opposite to that of the magnetic powder, and the magnetism of the second magnet 27 is the same as that of the magnetic powder, when the lignite coal powder and the magnetic powder are lifted by the drum 35, the first magnet 26 will attract the magnetic powder, thus intensifying the upward movement of the magnetic powder. When the lignite coal powder and the magnetic powder continue to flow, they will be repelled by the second magnet 27, causing the magnetic powder to move downward. This helps prevent the magnetic powder from moving excessively upward under the attraction of the first magnet 26 and the repulsion of the drum 35, thereby avoiding the magnetic powder spilling out of the treatment area (i.e., the area between the first sieve plate 24 and the second sieve plate 28). At the same time, the magnetic powder moving downward or upward will squeeze and disperse the agglomerated lignite coal powder, thus improving the flow state of the coal powder, and further enhancing the quality of dehydration and drying of the lignite coal powder. Although the magnetic powder spilling out of the treatment area can smoothly fall back onto the second sieve plate 24 through the first sieve plate 24, due to the fact that both the magnetic powder and the lignite coal powder are in a flowing state, during the falling process of the magnetic powder, the impact force on the lignite coal powder from the magnetic powder will be reduced, and the magnetic powder is unevenly distributed after falling, which is not conducive to the high-precision separation of the lignite coal powder, that is, it reduces the quality of dehydration and drying of the lignite coal powder. Since the weight of the lignite coal powder itself is relatively larger than that of the magnetic powder, and it neither generates repulsion with the drum 35 nor is attracted by the first magnet 26, the lignite coal powder will not overflow.

[0031] During the movement (i.e., the flowing process) of the magnetic powder and the coal powder on the second sieve plate 28, when the thermal imaging probe 25 detects that the lignite coal powder on the second sieve plate 28 is agglomerated, the two opposite electromagnets 29 at the corresponding position can be energized, and the magnetisms of the above two electromagnets 29 are made opposite, so that one electromagnet 29 attracts the magnetic powder and the other electromagnet 29 repels the magnetic powder. At this time, it is necessary to ensure that the electromagnet 29 attracting the magnetic powder is close to the agglomerated position of the lignite coal powder. Then, under the action of the electromagnetic force, the magnetic powder will move towards the area where the lignite coal powder is agglomerated and gather there, thus dispersing the agglomerated lignite coal powder at that place and increasing the heat transfer efficiency to the lignite coal powder at that place. When the thermal imaging probe 25 detects that the distribution of the lignite coal powder on the second sieve plate 28 is not very uniform, the rotation speed of the drum 35 at the corresponding position can be increased and the rotation direction of the drum 35 at the corresponding position can be adjusted by controlling the second motor 10 to disperse the coal powder from the area with a thicker accumulation to the area with a thinner accumulation, thereby effectively ensuring the efficiency and quality of dehydration and drying of the lignite coal powder.

[0032] The magnetic powder and the lignite pulverized coal that has completed drying and deashing are finally discharged from the second discharge pipe 14. At this time, the driving part is started to make the magnetic rotating roller 16 rotate. The magnetic powder discharged from the second discharge pipe 14 will pass through the rotating magnetic rotating roller 16 and be adsorbed by it. As the magnetic rotating roller 16 rotates, the adsorbed magnetic powder will be carried to the other end of the magnetic rotating roller 16 and unloaded or collected here. The dried and deashed lignite pulverized coal discharged from the second discharge pipe 14 will fall into the aggregate box after passing through the magnetic rotating roller 16, thus completing the collection of the upgraded lignite pulverized coal. The waste materials on the first sieve plate 24 and the mounting plate 30 will fall into the two recycling bins 18 respectively before the above collection process is completed. In addition, the dust discharged by the air outlet pipe 5 will enter the cyclone separation system 6. In the above system, the larger dust particles in the dust are effectively separated under the action of centrifugal force. The waste gas treated by the cyclone separation system 6 will then enter the bag filter 7 for further treatment. At this time, the tiny dust particles in the waste gas are intercepted, and the purified gas will be discharged. After that, the dust particles captured in the cyclone separation system 6 and the bag filter 7 are regularly cleaned and centrally treated or recycled.

[0033] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-precision dry ash removal and quality improvement process for low-quality coal, characterized in that, It includes the following technological steps: S1. Conveying and preprocessing: The heated magnetic powder and the lignite pulverized coal to be processed are conveyed into the stirring chamber (8), and the pulverized coal is preheated and preliminarily crushed and separated by the heated magnetic powder and the rotating stirring rod (33). S2. Vibration and blowing: After the preprocessing of the pulverized coal is completed, the solenoid valve is opened, the magnetic powder and the pulverized coal fall onto the first sieve plate (24), the vibration motor (11) is started to vibrate the housing (1), the hot air blower (4) and the blower (17) are started to blow air into the housing (1), and at the same time, the second motor (10) is started to rotate the drum (35). S3. Primary screening: The first motor (9) is controlled to make the first brush head (22) reciprocate. The vibration of the housing (1) can screen the pulverized coal, so that the pulverized coal with too large particles remains on the first sieve plate (24), the magnetic powder and the remaining pulverized coal fall onto the second sieve plate (28), and the first brush head (22) cooperates with the vibration of the housing (1) to accelerate the screening of the pulverized coal. S4. Secondary screening: The reciprocating movement of the first brush head (22) drives the reciprocating movement of the second brush head (23), so that the magnetic powder and the remaining pulverized coal on the second sieve plate (28) are evenly distributed, and under the vibration of the housing (1), the pulverized coal with too small particles and part of the dust in the pulverized coal fall onto the mounting plate (30), and the remaining dust is lifted to form dust. S5. Dewatering and drying: The waste materials on the first sieve plate (24) and the mounting plate (30) and the materials on the second sieve plate (28) move towards the recycling box (18) and the aggregate box under the vibration of the housing (1), and cooperate with the drum (35), the first magnet (26) and the second magnet (27) as well as hot air and cold air to complete the dewatering and drying of the pulverized coal. S6. Monitoring and regulation: During the above-mentioned moving process, if the thermal imaging probe (25) monitors that the pulverized coal agglomerates, the energized electromagnet (29) attracts the magnetic powder to break up the agglomerated pulverized coal. If the thermal imaging probe (25) monitors that the pulverized coal is unevenly distributed, the rotation speed and direction of the drum (35) are adjusted to disperse the pulverized coal from the thicker area to the thinner area. S7. Collection and recycling: The dried and deashed pulverized coal falls into the aggregate box, the magnetic powder is adsorbed by the magnetic rotating roller (16), the waste materials on the first sieve plate (24) and the mounting plate (30) respectively fall into the two recycling boxes (18), the dust is discharged through the air outlet pipe (5), and enters the bag filter (7) after passing through the cyclone separation system (6).

2. A high-precision dry ash removal and quality improvement method for low-quality coal, which is applied to the process described in claim 1 and uses the following device, including a housing (1) and a screw feeder (3). Two vibration motors (11) are symmetrically installed on the housing (1), and two shock-absorbing bases (12) are symmetrically installed at the bottom end of the housing (1). It is characterized in that, It also includes: A preprocessing mechanism, which is arranged on the housing (1) and the screw feeder (3), and is used to add the heated magnetic powder into the pulverized coal in the screw feeder (3) and carry out preliminary crushing, separation and drying. A screening and drying mechanism, which is arranged inside the housing (1) and is used to carry out secondary crushing, separation and drying of the pulverized coal entering the housing (1). A waste material recycling mechanism and a collection mechanism, both of which are arranged on the housing (1). The waste material recycling mechanism is used to recycle the impurities and dust in the pulverized coal in the housing (1), and the collection mechanism is used to collect the dried and deashed pulverized coal.

3. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 2, characterized in that, The preprocessing mechanism includes a feed inlet (2) and a mixing chamber (8). The feed inlet (2) is installed on a screw feeder (3) and is in communication with the input end of the screw feeder (3). The bottom end of the mixing chamber (8) is provided with a feed pipe (34), and the mixing chamber (8) is fixedly communicated with the inside of the housing (1) through the feed pipe (34). An electromagnetic valve is installed in the feed pipe (34). The top end of the mixing chamber (8) is provided with a conveying pipe (31), and the mixing chamber (8) is connected to the output end of the screw feeder (3) through the conveying pipe (31). The mixing chamber (8) is located at the top end of the housing (1) near the edge, and a third motor (32) is installed at the top end of the mixing chamber (8). The output end of the third motor (32) penetrates through the top wall of the mixing chamber (8) and is fixedly connected to a mixing rod (33).

4. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 2, characterized in that, The screening and drying mechanism includes a first sieve plate (24), a second sieve plate (28) and a mounting plate (30). The first sieve plate (24), the second sieve plate (28) and the mounting plate (30) are sequentially installed inside the housing (1) from top to bottom and are all inclined in a direction away from the screw feeder (3). The inclination angle of the second sieve plate (28) is smaller than that of the first sieve plate (24) and the mounting plate (30). The diameter of the sieve holes on the first sieve plate (24) is larger than that of the sieve holes on the second sieve plate (28). A blowing component is arranged on the housing (1) for blowing hot and cold air into the housing (1). An auxiliary component is arranged on the second sieve plate (28) for improving the separation and drying effect of the pulverized coal.

5. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 4, characterized in that The blowing component includes a hot air blower (4) and a blower (17). The hot air blower (4) and the blower (17) are both arranged on the ground, and the output ends of the hot air blower (4) and the blower (17) penetrate through the side wall of the housing (1) and are arranged upward. The hot air blower (4) and the blower (17) are both located between the second sieve plate (28) and the mounting plate (30). The blower (17) is close to one end of the housing (1) away from the screw feeder (3), and the hot air blower (4) is located between the screw feeder (3) and the blower (17).

6. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 5, characterized in that The auxiliary component includes two extension plates and a plurality of rollers (35). The two extension plates are respectively installed at the bottom end of the second sieve plate (28) near the two side edges. The outer wall of the extension plate is in contact with the inner wall of the housing (1). A plurality of rollers (35) are evenly rotatably connected to the two extension plates. A plurality of second motors (10) are evenly installed on the outer wall of the housing (1). The output ends of the plurality of second motors (10) sequentially penetrate through the outer wall of the housing (1) and one of the extension plates and are respectively fixedly connected to the plurality of rollers (35). A plurality of through grooves corresponding to the plurality of rollers (35) are provided through the top end of the second sieve plate (28). The part above the rollers (35) is located in the through grooves. The rollers (35) are made of a magnetic material, and the magnetism of the rollers (35) is the same as that of the magnetic powder. A plurality of air holes are evenly provided through the outer wall of the rollers (35). A ball (41) is rotatably connected inside the air hole. Rotating rods (36) are rotatably connected to two opposite inner walls inside the roller (35). A plurality of spiral fan blades (37) are evenly installed on the rotating rods (36). A second gear (40) is installed on the outer wall of the rotating rod (36) near one end edge. An internal gear ring (38) is installed on the inner wall of the roller (35). A first gear (39) is rotatably connected to one of the inner walls of the rotating rod (36). The internal gear ring (38) and the second gear (40) are both meshed with the first gear (39).

7. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 4, characterized in that It further includes a screening and regulating assembly. The screening and regulating assembly includes a mounting frame. The mounting frame is fixedly installed at one end of the housing (1) close to the screw feeder (3). A fixing rod (21) is fixedly installed inside the mounting frame. A first motor (9) is installed on the outer wall of the mounting frame. A connecting plate (20) is slidably connected to the fixing rod (21). The output end of the first motor (9) penetrates through the outer wall of the mounting frame and is fixedly connected to a lead screw (19). The end of the lead screw (19) far from the first motor (9) is rotatably connected to the inner wall of the mounting frame. The lead screw (19) is threadedly connected to the connecting plate (20). Two sliding rods are installed on the side of the connecting plate (20) facing the housing (1). Two chutes for the two sliding rods to slide through are respectively provided through one end of the housing (1). The ends of the two sliding rods far from the connecting plate (20) respectively pass through the two chutes and are respectively fixedly connected to a first brush head (22) and a second brush head (23). The bristles on the first brush head (22) are in contact with the top end of the first sieve plate (24). The second brush head (23) is located between the first sieve plate (24) and the second sieve plate (28). There is a gap between the bristles on the second brush head (23) and the second sieve plate (28).

8. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 7, characterized in that, It further includes an anti-overflow assembly and an efficiency-enhancing assembly. The anti-overflow assembly includes a plurality of first magnets (26) and a plurality of second magnets (27). The plurality of first magnets (26) and the plurality of second magnets (27) are both installed at the bottom end of the first sieve plate (24) and are arranged alternately. The magnetism of the first magnet (26) is opposite to the magnetism of the magnetic powder. The magnetism of the second magnet (27) is the same as the magnetism of the magnetic powder. The efficiency-enhancing assembly includes a plurality of thermal imaging probes (25) and a plurality of electromagnets (29). The plurality of thermal imaging probes (25) are evenly installed at the bottom end of the first sieve plate (24). The positions of the plurality of thermal imaging probes (25) are respectively located on the non-opposite sides of each adjacent first magnet (26) and second magnet (27). The plurality of electromagnets (29) are evenly and fixedly embedded in two opposite inner side walls of the housing (1). The bottom positions of the plurality of electromagnets (29) correspond to the top positions of the second sieve plate (28).

9. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 4, characterized in that The waste recycling mechanism includes a cyclone separation system (6), a bag filter (7) and two recycling bins (18). The cyclone separation system (6), the bag filter (7) and the two recycling bins (18) are all arranged on the ground. The output end of the cyclone separation system (6) is connected to the input end of the bag filter (7), and an air outlet pipe (5) is installed at the input end of the cyclone separation system (6). The cyclone separation system (6) is connected to the inside of the housing (1) through the air outlet pipe (5). The air outlet pipe (5) is located at the top of the housing (1). One end of the housing (1) far from the screw feeder (3) is fixedly connected with a first discharge pipe (13) and a third discharge pipe (15). The positions of the connections between the first discharge pipe (13) and the third discharge pipe (15) and the housing (1) correspond to the positions of the first sieve plate (24) and the mounting plate (30) respectively, and the positions of the bottom openings of the first discharge pipe (13) and the third discharge pipe (15) correspond to the positions of the two recycling bins (18) respectively.

10. A high-precision dry ash removal and quality improvement method for low-quality coal according to claim 4, characterized in that, The collection mechanism includes a second discharge pipe (14), an aggregate bin and two mounting platforms. The aggregate bin and the two mounting platforms are all arranged on the ground. The second discharge pipe (14) is fixedly connected to one end of the housing (1) far from the screw feeder (3), and the position of the connection between the second discharge pipe (14) and the housing (1) corresponds to the position of the second sieve plate (28). The position of the bottom opening of the second discharge pipe (14) corresponds to the position of the aggregate bin. The two mounting platforms are located at both ends of the aggregate bin, and a magnetic rotating roller (16) is rotatably connected between the two mounting platforms. A driving part for driving the magnetic rotating roller (16) to rotate is installed on one of the mounting platforms. The magnetic rotating roller (16) is located between the second discharge pipe (14) and the aggregate bin, and the magnetic rotating roller (16) is obliquely below the bottom opening of the second discharge pipe (14). The magnetism of the magnetic rotating roller (16) is opposite to the magnetism of the magnetic powder.

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