A dust collection system for lignite drying
By combining a cyclone dust collector, a closed oxygen-barrier screw conveyor, and a humidifying mixer, the problems of flammability, explosiveness, and dust generation in the production process of lignite pulverized coal were solved, achieving safe and efficient recycling of pulverized coal dust particles and reducing production risks and costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KAIYUAN DONGHONG ENERGY CO LTD
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-09
Smart Images
Figure CN122170634A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lignite drying technology, and specifically relates to a dust collection system for lignite drying. Background Technology
[0002] Existing methods for producing lignite pulverized coal mainly employ integrated drying, upgrading, and pulverizing processes, as well as superheated steam drying and molding processes. In both of these processes, cyclone dust collectors are the core equipment for achieving gas-solid separation. After the dust-laden, high-temperature flue gas enters the cyclone dust collector, most of the dried pulverized coal is separated and collected under centrifugal force, while the purified gas either enters subsequent dust removal equipment or is directly emitted.
[0003] In traditional separation and collection methods, cyclone dust collectors are usually equipped with rotary valves to discharge the separated coal powder into pipelines, which are then pneumatically conveyed to storage tanks by Roots blowers. This method has several drawbacks: (1) The collected coal powder is at a high temperature and has certain flammable and explosive properties. When mixed with air during transportation, it is very easy to form an explosive environment, posing a significant safety hazard; (2) The pneumatic conveying process generates severe dust, which not only causes material loss but also threatens the working environment and the health of operators; (3) The coal powder collected in this way is difficult to store stably directly and often requires additional cooling, explosion suppression, or inerting treatment, which increases the complexity of the process and operating costs. Overall, this method is risky and has poor controllability, making it difficult to meet the requirements of modern industrial production for safety, environmental protection, and high efficiency. Summary of the Invention
[0004] The purpose of this invention is to provide a dust collection system for drying lignite, so as to solve the problems of safety hazards and serious dust pollution in the existing technology.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a dust collection system for drying lignite, comprising a cyclone dust collector, a closed-loop oxygen-barrier screw conveyor, and a humidifying mixer; the ash discharge port at the bottom of the cyclone dust collector is connected to one end of the closed-loop oxygen-barrier screw conveyor; the bottom of the other end of the closed-loop oxygen-barrier screw conveyor is connected to the humidifying mixer via a pipe, and a belt conveyor is correspondingly installed at the discharge port of the humidifying mixer; The enclosed oxygen-barrier screw conveyor includes a sealed pipe, a rotating shaft, helical blades, flange A, a sealed bearing, and an explosion-proof geared motor. Flange A is installed at both ends of the sealed pipe. The rotating shaft passes through the sealed pipe and flange A, and helical blades are fixedly mounted on the outer wall inside the sealed pipe, with the outer edge of the helical blades contacting the inner wall of the sealed pipe. One end of the rotating shaft is connected to the explosion-proof geared motor, and the other end is rotatably connected via the sealed bearing. A mechanical seal connects the rotating shaft and flange A. After the dust-laden flue gas is conveyed to the cyclone dust collector, it is separated by the cyclone dust collector: the pulverized coal dust particles are separated from the airflow and captured on the wall of the collector, and then fall into the ash hopper by gravity and enter the closed oxygen-barrier screw conveyor; the closed oxygen-barrier screw conveyor transports the pulverized coal dust particles in one direction and puts them into the humidifying mixer; after entering the humidifying mixer, the pulverized coal dust particles come into contact with and mix with the water sprayed in the humidifying mixer, and form wet fine coal powder under the stirring of the stirring blades, and the wet fine coal powder is then discharged from the discharge port to the belt conveyor; the gas purified by the cyclone dust collector is discharged from the inner cylinder of the cyclone dust collector through the air outlet and connected to the wet scrubber through the pipeline.
[0006] Preferably, one end of the sealing pipe is sealed to the ash discharge port of the cyclone dust collector via a pipe and flange, and the other end is provided with a dust outlet for communication with the humidifying mixer.
[0007] Preferably, the humidifying mixer is a twin-shaft humidifying mixer with a sealing cover plate on top; the side wall of the humidifying mixer is connected to a spray pipe, and multiple nozzles are distributed on the spray pipe located inside the humidifying mixer.
[0008] Preferably, the water in the spray pipe is a calcium hydroxide solution with a concentration of 18-25%.
[0009] Preferably, in wet fine coal powder, the mass ratio of calcium hydroxide solution to coal dust particles is 1:(3~5).
[0010] Preferably, there are two cyclone dust collectors, and the two cyclone dust collectors are connected in parallel; the ash discharge port at the bottom of each cyclone dust collector is connected to a closed oxygen barrier screw conveyor; the dust-laden flue gas from the drum dryer enters the two cyclone dust collectors through pipelines, and the gas from the two outlets is then connected to the conveying pipelines respectively.
[0011] Beneficial effects: The production process of this invention is dust-free, avoiding environmental pollution; the closed oxygen-barrier screw conveyor prevents oxygen from entering the cyclone dust collector, making the risk of combustion and explosion zero and improving production safety; this invention also realizes the recycling of fly ash particles. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the present invention; Figure 2 This is an enlarged schematic diagram of the closed-loop oxygen-barrier screw conveyor of the present invention; Figure 3 This is a schematic diagram of the dried fine coal powder discharged from the humidifying mixer. Detailed Implementation
[0013] The embodiments of the present invention will be described in detail below with reference to the examples, but the scope of protection of the present invention is not limited to the following embodiments. Where specific techniques, connections, or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques, connections, or conditions described in the literature in the art or in accordance with the product manual. Materials, instruments, or equipment used without specified manufacturers are all conventional products that can be obtained by purchase.
[0014] like Figure 1 As shown, the present invention provides a dust collection system for drying lignite, including a cyclone dust collector 1, a closed oxygen-barrier screw conveyor 2, and a humidifying mixer 3. The ash discharge port 11 at the bottom of the cyclone dust collector 1 is connected to one end of the closed oxygen barrier screw conveyor 2; the bottom of the other end of the closed oxygen barrier screw conveyor 2 is connected to the humidifying mixer 3 through a pipe, and a belt conveyor 4 is installed at the discharge port 31 of the humidifying mixer 3; the humidifying mixer 4 is an existing product and can be purchased commercially.
[0015] like Figure 2 As shown, the enclosed oxygen barrier screw conveyor 2 includes a thickened sealing pipe 21, a rotating shaft 22, a screw blade 23, a flange A24, a sealed bearing 25, and an explosion-proof geared motor 26. Flanges A24 are provided at both ends of the sealing pipe 21. The rotating shaft 22 passes through the sealing pipe 21 and the flange A24, and the screw blade 23 is fixedly mounted on its outer wall inside the sealing pipe 21. The outer edge of the screw blade 23 contacts and connects to the inner wall of the sealing pipe 21. One end of the rotating shaft 22 is connected to the explosion-proof geared motor 26, and the other end is rotatably connected via the sealed bearing 25. A mechanical seal connects the rotating shaft 22 and the flange A24.
[0016] After the dust-laden flue gas is conveyed to the cyclone dust collector 1, it is separated by the cyclone dust collector 1: the fly ash particles are separated from the airflow and captured on the wall of the cyclone dust collector, and then, by gravity, the dust particles fall into the ash hopper and enter the closed oxygen-barrier screw conveyor 2; the closed oxygen-barrier screw conveyor 2 transports the fly ash particles in one direction and into the humidifying mixer 3; such as Figure 1 As shown, the fly ash particles move from right to left in the closed oxygen-barrier screw conveyor 2 under the action of the screw blades 23. By setting up the closed oxygen-barrier screw conveyor 2, oxygen is prevented from entering the cyclone dust collector 1. After the fly ash particles enter the humidifying mixer 3, they come into contact with and mix with the water sprayed in the humidifying mixer 3, and form wet fine coal powder under the stirring of the stirring blades. The wet fine coal powder is then discharged from the discharge port 31 to the belt conveyor 4. The gas purified by the cyclone dust collector 1 is discharged from the inner cylinder of the cyclone dust collector 1 through the air outlet 12, and is connected to the wet dust collector through the pipeline to enter the subsequent processing process.
[0017] In a further optimized design, one end of the sealing pipe 21 is sealed to the ash discharge port 11 of the cyclone dust collector 1 via a pipe and flange 5, while the other end has a dust outlet 27 for communication with the humidifying mixer 3. The humidifying mixer 3 is a twin-shaft humidifying mixer with a sealing cover plate 32 on top; a spray pipe 33 is connected to the side wall of the humidifying mixer 3, and multiple spray nozzles 34 are distributed on the spray pipe 33 located inside the humidifying mixer 3.
[0018] Specifically, the water in the spray pipe 33 is a calcium hydroxide solution with a concentration of 18-25%; the calcium hydroxide solution is used to absorb sulfur dioxide in the coal dust particles; and in the formed wet fine coal powder, the mass ratio of calcium hydroxide solution to coal dust particles is 1:(3-5).
[0019] To further optimize the design, two cyclone dust collectors 1 are installed, and the two cyclone dust collectors 1 are connected in parallel. The ash discharge port 11 at the bottom of each cyclone dust collector 1 is connected to a closed oxygen barrier screw conveyor 2. The length of the closed oxygen barrier screw conveyor 2 can be adjusted according to actual needs. The dust-laden flue gas from the drum dryer enters the two cyclone dust collectors 1 through pipelines. The coal dust particles are separated from the airflow and enter the corresponding closed oxygen barrier screw conveyor 2. The purified gas is connected to the conveying pipeline 13 from the two air outlets 12 and enters the wet dust collector through the conveying pipeline 13.
[0020] The specific process of this invention is as follows: (1) High-temperature flammable and explosive materials with sparks at 140-160℃ enter the closed oxygen barrier screw conveyor from the ash discharge port of the cyclone dust collector; the screw blades in the closed oxygen barrier screw conveyor rotate under the drive of the explosion-proof geared motor, thereby driving the high-temperature flammable and explosive materials to move towards the discharge port end. The closed oxygen barrier screw conveyor can transport high-temperature flammable and explosive materials in a timely manner, keeping the outlet at the bottom of the cyclone dust collector unobstructed; because the screw blades in the closed oxygen barrier screw conveyor are in contact with the inner wall of the thickened sealing pipe, forming a one-way conveying channel, the risk of oxygen entering the cyclone dust collector and causing an explosion is avoided. (2) The material enters the closed-loop humidifying mixer through the pipe from the closed-loop oxygen barrier screw conveyor. At this time, the temperature drops to 95-115℃. The alkaline water sprayed from the spray pipe in the humidifying mixer comes into contact with the material and mixes with it, so that the sulfur dioxide in the material reacts with the alkaline water. Under the stirring of the mixer, the material and alkaline water are fully mixed to form wet fine coal powder, which is then transported to the discharge port of the humidifying mixer. At this time, the material temperature drops to 40-50℃. Alkaline water is a calcium hydroxide solution, which can be used as an absorbent to absorb sulfur dioxide. The following are the chemical reaction steps: SO2 is absorbed by the droplets: SO2 + H2O → H2SO3 Reaction with slaked lime: Ca(OH)₂ + H₂SO₃ → CaSO₃ + 2H₂O Crystallization: CaSO3 (liquid) → CaSO3 (solid) Partial oxidation: CaSO3(liquid) + 1 / 2O2(liquid) → CaSO4(liquid) (3) The wet fine coal powder material falls from the discharge port into the belt conveyor and is transported to the finished product silo. At this time, the temperature drops to 30-40℃. The finished product after drying the wet fine coal powder is shown in the figure. Figure 3 As shown, the process generates no dust, avoids environmental pollution, has zero risk of combustion and explosion, and improves production safety.
[0021] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.
Claims
1. A dust collection system for drying lignite, characterized in that, It includes a cyclone dust collector (1), a closed oxygen-barrier screw conveyor (2), and a humidifying mixer (3); among which, The ash discharge port (11) at the bottom of the cyclone dust collector (1) is connected to one end of the closed oxygen barrier screw conveyor (2); the bottom of the other end of the closed oxygen barrier screw conveyor (2) is connected to the humidifying mixer (3) through a pipe, and a belt conveyor (4) is set at the discharge port (31) of the humidifying mixer (3). The enclosed oxygen barrier screw conveyor (2) includes a sealing pipe (21), a rotating shaft (22), a screw blade (23), a flange A (24), a sealed bearing (25), and an explosion-proof geared motor (26); both ends of the sealing pipe (21) are provided with flanges A (24); the rotating shaft (22) passes through the sealing pipe (21) and the flange A (24), and the screw blade (23) is fixedly provided on the outer wall inside the sealing pipe (21), and the outer edge of the screw blade (23) is in contact with the inner wall of the sealing pipe (21); one end of the rotating shaft (22) is connected to the explosion-proof geared motor (26), and the other end is rotatably connected through the sealed bearing (25); the rotating shaft (22) and the flange A (24) are connected by a mechanical seal; After the dust-laden flue gas is transported to the cyclone dust collector (1), it is separated by the cyclone dust collector (1): the coal dust particles are separated from the airflow and captured on the wall of the collector, and then the dust particles fall into the ash hopper and enter the closed oxygen barrier screw conveyor (2) by gravity; the closed oxygen barrier screw conveyor (2) transports the coal dust particles in one direction and enters the humidifying mixer (3); after the coal dust particles enter the humidifying mixer (3), they come into contact with the water sprayed in the humidifying mixer (3) and are mixed with the water sprayed in the humidifying mixer (3), and form wet fine coal powder under the stirring of the stirring blades. The wet fine coal powder is then discharged from the discharge port (31) to the belt conveyor (4); the gas purified by the cyclone dust collector (1) is discharged from the inner cylinder of the cyclone dust collector (1) through the air outlet (12) and connected to the wet dust collector through the pipeline.
2. The dust collection system for lignite drying according to claim 1, characterized in that, One end of the sealing pipe (21) is sealed to the ash discharge port (11) of the cyclone dust collector (1) through the pipe and flange B (5), and the other end is opened to have a dust outlet (27) for communication with the humidifying mixer (3).
3. A dust collection system for drying lignite according to claim 1 or 2, characterized in that, The humidifying mixer (3) is a twin-shaft humidifying mixer with a sealing cover plate (32) on top; a spray pipe (33) is connected from the side wall of the humidifying mixer (3), and multiple nozzles (34) are distributed on the spray pipe (33) inside the humidifying mixer (3).
4. A dust collection system for lignite drying according to claim 1 or 2, characterized in that, The water in the spray pipe (33) is a calcium hydroxide solution with a concentration of 18-25%.
5. A dust collection system for drying lignite according to claim 4, characterized in that, In wet fine coal powder, the mass ratio of calcium hydroxide solution to coal dust particles is 1:(3~5).
6. A dust collection system for lignite drying according to claim 1 or 4, characterized in that, Two cyclone dust collectors (1) are provided, and the two cyclone dust collectors (1) are connected in parallel; the ash discharge port (11) at the bottom of each cyclone dust collector (1) is connected to a closed oxygen barrier screw conveyor (2); the dust-laden flue gas from the drum dryer enters the two cyclone dust collectors (1) through the pipes respectively, and the gas from the two air outlets (12) is then connected to the conveying pipes (13) respectively.