Clean processing and upgrading equipment for power coal

Abstract

The invention discloses clean processing and upgrading equipment for power coal, belongs to the technical field of advanced green coal dressing, and is used for solving at least one of the problems of poor separation effect, small separation particle size range and low separation precision of fine-grained and viscous and humidified power coal in the prior art. According to the system, an oversize outlet of a first-stage classifying screen is connected with a feeding port of an X-ray sorting unit, discharging ports of the X-ray sorting unit are divided into a first-stage clean coal discharging port and a first-stage gangue discharging port, and the first-stage clean coal discharging port is connected with a feeding port of a second-stage classifying screen through a crushing unit; an undersize outlet of the first-stage classifying screen is connected with a feeding port of the second-stage classifying screen, an oversize outlet of the second-stage classifying screen is connected with a feeding port of the dry-method sorting unit, discharging ports of the dry-method sorting unit are a second-stage clean coal discharging port and a second-stage gangue discharging port respectively, and an undersize outlet of the second-stage classifying screen is connected with the low-temperature steam drying unit. The method can be used for clean processing and upgrading of the power coal.

Description

Technical Field

[0001] This invention belongs to the field of advanced green coal preparation technology, and in particular relates to a clean processing and upgrading equipment for thermal coal. Background Technology

[0002] For coal dewatering and upgrading technologies in water-scarce areas, dewatering screens or centrifuges are mainly used for dewatering coarse particles, while sedimentation centrifuges, vacuum filters, or filter presses are mainly used for dewatering fine particles.

[0003] However, for sticky and wet thermal coal, the particle size range is relatively wide, usually 50-0 mm, and the moisture content is high. The above-mentioned dewatering equipment cannot meet the requirements for moisture content and feed particle size. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a clean processing and upgrading equipment for thermal coal, in order to solve at least one of the following problems in the prior art: poor separation effect of fine-grained and sticky thermal coal, small separation particle size range, and low separation accuracy.

[0005] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a clean processing and upgrading equipment for thermal coal, including a primary grading screen, an X-ray separation unit, a secondary grading screen, a dry separation unit, and a low-temperature steam drying unit; The outlet of the primary grading screen is connected to the inlet of the X-ray separation unit. The outlet of the X-ray separation unit is divided into a primary clean coal outlet and a primary gangue outlet. The primary clean coal outlet is connected to the inlet of the secondary grading screen through the crushing unit. The under-screen outlet of the primary grading screen is connected to the inlet of the secondary grading screen. The outlet of the secondary grading screen is connected to the inlet of the dry separation unit. The outlets of the dry separation unit are the secondary clean coal outlet and the secondary gangue outlet. The under-screen outlet of the secondary grading screen is connected to the low-temperature steam drying unit. The outlet of the low-temperature steam drying unit is the dried coal powder outlet.

[0006] Furthermore, the aperture of the primary grading sieve is 50 mm, and the aperture of the secondary grading sieve is 3 mm.

[0007] Furthermore, the dry sorting unit is either a vibration-grade dry sorting unit or a fluidized bed sorting unit.

[0008] Furthermore, the vibratory cascade dry sorting unit includes a cascade sorting bed, a vibrator for driving the cascade sorting bed to vibrate, and an air distributor for supplying gas into the cascade sorting bed.

[0009] Furthermore, the tiered sorting bed is shaped like an inclined ladder.

[0010] Furthermore, the tiered sorting bed is divided into a distribution section, a multi-stage sorting section, and a discharge section in sequence along the flow direction of the material on the secondary grading screen.

[0011] Furthermore, the fluidized bed sorting unit includes a light medium feed tank, a heavy medium feed tank, a fluidized bed tank, a light medium solenoid valve, and a heavy medium solenoid valve. The light medium feed tank is connected to the fluidized bed tank through the light medium solenoid valve, and the heavy medium feed tank is connected to the fluidized bed tank through the heavy medium solenoid valve.

[0012] Furthermore, the low-temperature steam drying unit is a steam tube rotary dryer.

[0013] Furthermore, the steam tube rotary dryer includes a drying tank and heat exchange tubes disposed within the drying tank, with steam introduced into the heat exchange tubes as the heat transfer medium.

[0014] Furthermore, there are multiple heat exchange tubes arranged in concentric circles.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: A) The clean processing and upgrading equipment for thermal coal provided by this invention, through the synergistic action of a primary grading screen, an X-ray sorting unit, a secondary grading screen, a dry sorting unit, and a low-temperature steam drying unit, separates 300-50mm large lump raw coal and 50-0mm moist sticky raw coal. Through a modular design of particle size classification, process matching, and synergistic control, it constructs a full-size dry upgrading path covering coarse, medium, and fine-grained coal, breaking through the limitations of traditional single sorting technologies in terms of particle size adaptability. It can achieve efficient full-size gangue removal, dewatering, and deashing treatment of sticky wet thermal coal with a wide particle size range (300-0mm). This not only significantly increases the yield of clean coal but also effectively reduces the steam temperature during the drying process through low-temperature steam drying, reducing solid waste emissions. It provides a new solution for the clean processing and upgrading of sticky wet thermal coal in water-scarce areas. Simultaneously, for fine-grained sticky wet thermal coal with high moisture content, the moisture content is significantly reduced after low-temperature steam drying, providing favorable conditions for subsequent precise coal blending.

[0016] B) The power coal cleaning and upgrading equipment provided by this invention has an X-ray sorting unit suitable for efficient gangue removal of large coal pieces, a dry sorting unit that achieves synergistic upgrading of intermediate-sized coal by deashing and dehydration, and a low-temperature steam drying unit for indirect and mild drying of fine coal.

[0017] C) The clean processing and upgrading equipment for thermal coal provided by this invention has the characteristics of high-precision separation and strong operational stability of the X-ray intelligent dry separation unit and the dry separation unit. The combination of the two can further improve the separation efficiency and ensure the stability and consistency of the quality of clean coal.

[0018] D) The clean processing and upgrading equipment for thermal coal provided by this invention addresses the limitations imposed by natural conditions in arid and water-scarce regions by introducing a low-temperature steam drying unit. This unit uses steam at 90-150℃ as a heat source and utilizes waste heat from power plants to achieve cascaded energy utilization. No solid waste is generated during the drying process, and the steam condensate can be recycled, exhibiting significant energy-saving and environmental protection characteristics.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 This is a schematic diagram of the structure of the power coal clean processing and upgrading equipment provided in Embodiment 1 of the present invention, wherein the dry separation unit is a vibrating stepped dry separation unit; Figure 2 This is a schematic diagram of the structure of the power coal clean processing and upgrading equipment provided in Embodiment 1 of the present invention, wherein the dry separation unit is a fluidized bed separation unit; Figure 3 This is a schematic diagram of the structure of the stirring blades in the power coal clean processing and upgrading equipment provided in Embodiment 1 of the present invention.

[0022] Figure label: 1- Primary grading screen; 2- X-ray sorting unit; 3- Secondary grading screen; 4- Cascade sorting bed; 5- Vibrator; 6- Air distributor; 7- Light medium feed tank; 8- Heavy medium feed tank; 9- Fluidized bed tank; 10- Light medium solenoid valve; 11- Heavy medium solenoid valve; 12- Stirring shaft; 13- Stirring blades; 14- Drying tank; 15- Heat exchanger tubes. Detailed Implementation

[0023] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0024] Example 1 This embodiment provides a clean processing and upgrading device for thermal coal. See [link / reference] Figure 1It includes a primary grading sieve 1, an X-ray sorting unit 2, a secondary grading sieve 3, a dry sorting unit (e.g., a vibrating step dry sorting unit or a fluidized bed sorting unit), and a low-temperature steam drying unit.

[0025] The primary grading screen 1 has its oversize outlet connected to the inlet of the X-ray sorting unit 2. The outlet of the X-ray sorting unit 2 is divided into a primary clean coal outlet and a primary gangue outlet. The primary clean coal outlet is connected to the inlet of the secondary grading screen 3 through a crushing unit. The undersize outlet of the primary grading screen 1 is connected to the inlet of the secondary grading screen 3. The oversize outlet of the secondary grading screen 3 is connected to the inlet of the dry sorting unit. The outlets of the dry sorting unit are the secondary clean coal outlet and the secondary gangue outlet. The undersize outlet of the secondary grading screen 3 is connected to the low-temperature steam drying unit. The outlet of the low-temperature steam drying unit is the dried coal powder outlet.

[0026] For example, the particle size of primary clean coal is 300-50mm, the particle size of primary gangue is 300-50mm, the particle size of secondary clean coal is 50-3mm, the particle size of secondary gangue is 50-3mm, and the particle size of dry coal powder is 3-0mm.

[0027] Compared with existing technologies, the clean processing and upgrading equipment for thermal coal provided in this embodiment, on the one hand, through the synergistic action of the primary grading screen 1, X-ray separation unit 2, secondary grading screen 3, dry separation unit, and low-temperature steam drying unit, separates 300-50mm large lump raw coal and 50-0mm moist sticky raw coal, respectively. Through modular design of particle size classification, process matching, and synergistic control, it constructs a full-size dry upgrading path covering coarse, medium, and fine coal particles, breaking through the limitations of traditional single separation technologies in terms of particle size adaptability. This technology enables efficient removal of gangue, dewatering, and deashing of all particle sizes of sticky, wet thermal coal with a wide particle size range (300-0mm). This not only significantly increases the yield of clean coal but also effectively reduces the steam temperature during the drying process through low-temperature steam drying, thereby reducing solid waste emissions. It provides a novel solution for the clean processing and upgrading of sticky, wet thermal coal in water-scarce areas. At the same time, for fine-particle sticky, wet thermal coal with high moisture content in the raw coal, the moisture content is significantly reduced after low-temperature steam drying, providing favorable conditions for subsequent precise coal blending.

[0028] Specifically, the X-ray sorting unit 2 is suitable for efficient removal of gangue from large coal pieces, the dry sorting unit realizes the synergistic upgrading of deashing and dehydration of intermediate-sized coal, and the low-temperature steam drying unit is used for indirect and mild drying of fine coal.

[0029] On the other hand, the X-ray intelligent dry separation unit and the dry separation unit have the characteristics of high-precision separation and strong operational stability. The combination of the two can further improve the separation efficiency and ensure the stability and consistency of the quality of clean coal.

[0030] On the other hand, in response to the natural limitations of arid and water-scarce regions, a low-temperature steam drying unit is introduced. This unit uses steam at 90-150℃ as a heat source and utilizes waste heat from power plants to achieve cascaded energy utilization. No solid waste is generated during the drying process, and the steam condensate can be recycled, exhibiting significant energy-saving and environmental protection characteristics.

[0031] For example, the aperture of the primary grading sieve 1 is 50 mm, and the aperture of the secondary grading sieve 3 is 3 mm.

[0032] The dry sorting unit is a vibrating step-dry sorting unit.

[0033] For the structure of the vibration-grade dry sorting unit, see [link / reference]. Figure 1 It includes a stepped sorting bed 4, a vibrator 5 for driving the stepped sorting bed 4 to vibrate, and a gas distributor 6 for supplying gas into the stepped sorting bed.

[0034] Among them, the stepped sorting bed 4 is inclined and stepped, and is divided into a distribution section, a multi-stage sorting section and a discharge section in sequence along the flow direction of the material on the screen of the secondary grading screen 3.

[0035] Both the vibrator 5 and the air distributor 6 are located at the bottom of the stepped sorting bed 4. The vibrator 5 provides horizontal and vertical composite vibration, which makes the material on the secondary grading screen 3 loose and jump forward. Its amplitude and frequency are adjustable, so as to adapt to the material on the secondary grading screen 3 with different particle sizes / densities. The air distributor 6 provides uniform upward airflow.

[0036] The vibrating ladder dry sorting unit with the above structure achieves full loosening and stratification of the material on the secondary grading screen 3 through the combined vibration generated by the vibrator 5 and the uniform upward airflow provided by the air distributor 6.

[0037] In the distribution section, the material is evenly distributed. Upon entering the multi-stage separation section, the material from the second-stage grading screen (screen 3) of different densities and particle sizes is stratified according to density differences under the combined action of vibration and airflow; heavier materials sink, and lighter materials float. Finally, in the discharge section, the heavy material is discharged as gangue, and the lighter material is collected as clean coal. This separation method not only improves separation accuracy but also enhances the equipment's adaptability to different materials, ensuring the stability and efficiency of the separation effect. Simultaneously, the vibrating cascade dry separation unit has low operating energy consumption and is easy to maintain, further improving the economy and practicality of the entire thermal coal clean processing and upgrading equipment.

[0038] The dry sorting unit is a fluidized bed sorting unit.

[0039] For the structure of the fluidized bed sorting unit, see [link to relevant documentation]. Figure 2It includes a light medium feeding tank 7, a heavy medium feeding tank 8, a fluidized bed tank 9, a light medium solenoid valve 10, a heavy medium solenoid valve 11, and a stirring assembly, an air supply assembly, and a bed density collector installed in the fluidized bed tank 9. The light medium feeding tank 7 is connected to the fluidized bed tank 9 through the light medium solenoid valve 10, and the heavy medium feeding tank 8 is connected to the fluidized bed tank 9 through the heavy medium solenoid valve 11.

[0040] The fluidized bed sorting unit with the above-described structure can flexibly adjust the bed density within the fluidized bed by precisely controlling the supply of light and heavy media, combined with the synergistic effect of the stirring and air supply components, thus achieving accurate sorting of materials with different densities. The bed density acquisition device monitors and feeds back bed density data in real time, providing a basis for dynamic adjustment of the media supply and ensuring the stability and efficiency of the sorting process.

[0041] It should be noted that when the bed density is not within the bed density threshold range and the bed density needs to be adjusted, both the heavy medium solenoid valve 11 and the light medium solenoid valve 10 are in the open state. If the bed density is lower than the bed density threshold range, the opening degree of the heavy medium solenoid valve 11 is greater than that of the light medium solenoid valve 10. If the bed density is higher than the bed density threshold range, the opening degree of the light medium solenoid valve 10 is greater than that of the heavy medium solenoid valve 11.

[0042] In this way, firstly, the heavy medium solenoid valve 11 and the light medium solenoid valve 10 are both in the open state. By adjusting the different opening degrees, the bed density is adjusted so that the density of the medium supplied to the fluidized bed tank 9 is between the density of the light medium and the density of the heavy medium. This reduces the density difference between the newly added medium and the original bed medium, reduces the impact on the bed when the light medium or heavy medium is supplied alone, and achieves a gradual adjustment of the bed density.

[0043] Secondly, adding only a single medium often makes it difficult to quickly and accurately adjust the bed density to the target range. However, by mixing light and heavy media in different proportions, the combination of media entering the fluidized bed tank 9 can be flexibly and accurately controlled according to the deviation between the actual bed density and the threshold range, thereby achieving more efficient and accurate adjustment of the bed density.

[0044] While the agitation assembly can improve the mixing uniformity of light and heavy media, it inevitably affects the stability of the fluidized bed. Therefore, the agitation assembly includes an agitation shaft 12 and multiple agitation blades 13. The agitation blades 13 are arranged in a radial pattern, and the plane formed by the multiple agitation blades 13 divides the inner cavity of the fluidized bed tank 9 into an upper media mixing zone and a lower fluidization separation zone.

[0045] The connecting end of the stirring blade 13 is fixedly connected to the stirring shaft 12. The suspended end of the stirring blade 13 is suspended. The upper surface of the stirring blade 13 is a concave arc surface. The thickness of the suspended end of the stirring blade 13 remains constant. The thickness on one side of the connecting end is equal to the thickness of the suspended end. The thickness of the connecting end gradually decreases from one side to the other. The lower surface of the stirring blade 13 is a horizontal plane. (See [reference]) Figure 3 .

[0046] The mixing assembly has a mixing mode and a discharge mode. In mixing mode, the mixing shaft 12 drives the mixing blades 13 to rotate forward. The concave surface of the upper surface forms a guide surface, and the medium, after being enclosed by the concave surface, moves in a circular motion along an arc trajectory. Simultaneously, due to the difference in thickness of the mixing blades 13, an upward component force is generated, creating a combined disturbance of horizontal rotation and vertical tumbling, promoting the mixing of heavy and light media. Meanwhile, the lower surface of the mixing blades 13, due to its planar and uniform thickness structure, minimizes disturbance to the fluidized bed below. In discharge mode, the mixing shaft 12 drives the mixing blades 13 to rotate in the opposite direction. The concave surface of the upper surface forms a guide surface, and the medium, after being enclosed by the concave surface, moves in a circular motion along an arc trajectory. Simultaneously, due to the difference in thickness of the mixing blades 13, a downward component force is generated, promoting the gradual and slow flow of heavy and light media from the gaps in the mixing blades 13 into the fluidized separation zone.

[0047] In this way, the stirring component adopts two working modes: forward rotation and reverse rotation, corresponding to the two functional states of mixing and discharging, respectively. During forward rotation, the stirring component thoroughly agitates the medium newly supplied into the fluidized bed tank 9, promoting uniform mixing between the heavy and light media and ensuring that the heavy and light media achieve the required dispersion effect. During reverse rotation, it effectively promotes the orderly discharge of the heavy and light media. This not only significantly improves the consistency of the mixing process but also helps maintain the dynamic stability of the fluidized bed system, reducing operational fluctuations caused by uneven distribution or poor flow of the heavy and light media, thereby ensuring the reliability and controllability of the overall process.

[0048] To ensure full utilization of the dried coal powder, the outlet of the dried coal powder is connected to the inlet of the light medium feed tank 7, using the dried coal powder as the light medium. This is because the dried coal powder has a small particle size and low density, which are similar to the physical properties of the light medium, thus meeting the basic requirements for the light medium in the fluidized bed separation process.

[0049] In this way, feeding the dried coal powder as a light medium into the fluidized bed tank 9 achieves several advantages. First, it enables the reuse of dried coal powder, reducing resource waste and lowering production costs. Second, the participation of dried coal powder as a light medium in the separation process eliminates the need for additional light medium procurement, reducing the introduction of external media, simplifying media supply complexity and costs, and minimizing potential environmental impacts from improper media handling. Furthermore, the synergistic effect of dried coal powder with the heavy medium within the fluidized bed allows for better adjustment of bed density, improving separation accuracy and efficiency, and further enhancing the performance and economic benefits of the entire thermal coal clean processing and upgrading equipment.

[0050] The low-temperature steam drying unit is a steam tube rotary dryer.

[0051] For the structure of the steam tube rotary dryer, see [link to relevant documentation]. Figures 1 to 2 It includes a drying tank 14 and a heat exchange tube 15 disposed in the drying tank 14, and steam is introduced into the heat exchange tube 15 as a heat transfer medium.

[0052] For example, there are multiple heat exchange tubes 15, which are arranged in concentric circles.

[0053] This type of steam-tube rotary dryer utilizes waste heat steam generated during power plant production as a drying heat source for efficient and uniform indirect drying of sticky, wet pulverized coal. The steam temperature is typically controlled between 90 and 150°C, meeting the heat requirements for drying while minimizing material property changes caused by excessively high temperatures. The entire drying process takes place in a closed environment, generating no solid waste emissions, effectively reducing secondary environmental pollution and significantly lowering the risk of spontaneous combustion or explosion of pulverized coal due to dust accumulation. After heat exchange, the steam condenses into liquid water, which, after simple water treatment and purification, can be completely recycled, achieving zero emissions in the production process. This equipment not only meets the high throughput requirements of large-scale sorting processes but also effectively solves the technical problem of easy agglomeration and difficulty in efficient deagglomeration of sticky, wet fine-particle materials during drying, resulting in significant environmental and economic benefits.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for clean processing and upgrading thermal coal, characterized in that, It includes a primary grading sieve, an X-ray sorting unit, a secondary grading sieve, a dry sorting unit, and a low-temperature steam drying unit; The outlet of the primary grading screen is connected to the inlet of the X-ray separation unit. The outlet of the X-ray separation unit is divided into a primary clean coal outlet and a primary gangue outlet. The primary clean coal outlet is connected to the inlet of the secondary grading screen through a crushing unit. The under-screen outlet of the primary grading screen is connected to the inlet of the secondary grading screen. The outlet of the secondary grading screen is connected to the inlet of the dry separation unit. The outlets of the dry separation unit are the secondary clean coal outlet and the secondary gangue outlet. The under-screen outlet of the secondary grading screen is connected to the low-temperature steam drying unit. The outlet of the low-temperature steam drying unit is the dried coal powder outlet.

2. The power coal clean processing and upgrading equipment according to claim 1, characterized in that, The primary grading sieve has a sieve aperture of 50 mm, and the secondary grading sieve has a sieve aperture of 3 mm.

3. The power coal clean processing and upgrading equipment according to claim 1, characterized in that, The dry sorting unit is either a vibration-grade dry sorting unit or a fluidized bed sorting unit.

4. The power coal clean processing and upgrading equipment according to claim 3, characterized in that, The vibratory cascade dry sorting unit includes a cascade sorting bed, a vibrator for driving the cascade sorting bed to vibrate, and an air distributor for supplying gas into the cascade sorting bed.

5. The power coal clean processing and upgrading equipment according to claim 4, characterized in that, The tiered sorting bed is in the shape of an inclined ladder.

6. The power coal clean processing and upgrading equipment according to claim 5, characterized in that, The tiered sorting bed is divided into a distribution section, a multi-stage sorting section, and a discharge section in sequence along the flow direction of the material on the screen of the secondary grading screen.

7. The power coal clean processing and upgrading equipment according to claim 3, characterized in that, The fluidized bed sorting unit includes a light medium feed tank, a heavy medium feed tank, a fluidized bed tank, a light medium solenoid valve, and a heavy medium solenoid valve. The light medium feed tank is connected to the fluidized bed tank through the light medium solenoid valve, and the heavy medium feed tank is connected to the fluidized bed tank through the heavy medium solenoid valve.

8. The power coal clean processing and upgrading equipment according to claim 1, characterized in that, The low-temperature steam drying unit is a steam tube rotary dryer.

9. The power coal clean processing and upgrading equipment according to claim 8, characterized in that, The steam tube rotary dryer includes a drying tank and heat exchange tubes disposed inside the drying tank, wherein steam is introduced into the heat exchange tubes as a heat transfer medium.

10. The power coal clean processing and upgrading equipment according to claim 9, characterized in that, The heat exchange tubes are multiple, and the multiple heat exchange tubes are arranged in concentric circles.

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