Generally, the dust in the aggregate plant mainly comes from the discharge point of the crushing and screening equipment, the transportation and transfer point, the storage and unloading point of the aggregate, and the dust generated during the loading of the aggregate. This article will share the dust control technology of the quarry.
Process design of dust removal system
The dust removal system adopts a sealed or suction hood to extract dust, and the method of dust removal equipment purification. The dust collected by the dust collector is transported to the ash silo by the silo pump.
The dust removal process adopts the dust source point sealed mechanical dust extraction, and the airtight cover adopts two forms of semi-closed and partially closed. The arrangement is on the premise that the production operation is not affected. The airtight suction cover of this system: belt conveyor seal, crusher seal and vibration screen seal.
Material receiving seal of belt conveyor
The conveyor belt unloading point and receiving point stones are squeezed, impacted, and induced to produce a large amount of dust. At the same time, dust will also be generated when the conveyor belt transports crushed stones. Therefore, the conveyor belt should be sealed, taking into account the needs of production and maintenance and savings The material is sealed with a single-layer cover, and the conveyor belt must be tightly sealed. The airtight cover and the tape baffle are flexibly connected by a buckle, which facilitates the recovery of the airtight cover after the conveyor belt is overhauled.
Sealing of the crusher
The casing of the crusher is sealed, and only dust is generated at the feed and discharge points. The material is discharged into the crusher through the chute, and the dust enters the chute with the material to induce dust-laden air, part of which enters the crusher, and the other part diffuses upwards. Therefore, the feed inlet and the lower discharge port of the crusher should be airtightly sucked. Processing conditions, the screen surface of the vibrating screen is directly connected to the feed port of the crusher, so a closed suction hood is set at the feed port of the crusher.
Design of suction hood
In order to improve the dust suction effect and reduce the exhaust air volume, effective measures should be taken to prevent the dust from spreading and make the dust hood close to the dust spreading area. The exhaust pipe of the dust suction hood should be set in the center of the dust diffusion zone, and the ratio of the area of the hood to the area of the exhaust pipe can be up to 16:1. Determining an appropriate dust suction wind speed is conducive to effective dust collection without inhaling large particles of dust, which settle in the air duct, block the duct, and affect the dust removal effect.
The design process is to arrange the pipes according to the position of the suction hood and the dust collector, determine the pipe diameter according to the exhaust air volume and the selected flow rate, and then adjust the pipe system according to the resistance balance method, optimize the design, and observe the following principles:
To ensure that the air volume of each suction point meets the design requirements, and to make the pipeline the shortest under the premise of not hindering the production operation.
In order to prevent dust accumulation in the pipe and facilitate cleaning, the air pipe should be laid as far as possible vertically or inclined (inclination angle ≥45°). Under special circumstances, it must be laid horizontally. The horizontal pipe should have sufficient airflow speed (16-20m/s) to prevent Dust is deposited in the tube.
In the dust removal system, the dust collector is one of the main equipment, and the correct selection of the dust collector is an important part of the dust removal work.
According to the nature of the water source and dust at the aggregate processing site, a bag filter is selected. Its working principle is:
The dust-containing gas enters the air inlet of the dust collector through the pipeline. The larger particles of dust in the gas settle in the dust collector box under the action of gravity due to the slowdown of the airflow speed, and the smaller particles enter the microporous membrane filter material with the airflow. .
Under the action of the pressure difference, the dust-containing airflow is filtered on the filter bag, and the dust is trapped on the filter bag, and the filtered air enters the upper box of the dust collector through the filter bag and is discharged through the outlet pipe.
When the dust on the surface of the filter bag accumulates to a certain thickness, it will fall off by its own weight, and the dust sticking to the filter bag will be cleaned by compressed air controlled by PLC.
Since the filter material is different from the ordinary filter material (bag), even when the dust is wet, it can achieve the purpose of good dust removal. The collected ash is transported to the ash silo by the ash unloading valve at the lower part of the dust collector and the silo pump.
(1) Coarse crushing and medium crushing workshop: 1 jaw crusher, feeding and discharging, a total of 2 dust production points. Middle crushing workshop: 4 hydraulic cone crushers, feeding and discharging, a total of 8 dust production points, equipped with 1 SLQM96-7 dust collector.
(2) Inspection and screening workshop: 2 sets of vibrating screens, feeding and discharging, a total of 5 dust production points, equipped with 1 set of SLQM96-8 dust collector.
(3) Fine crushing workshop: 3 vertical shaft impact crushers, feeding and discharging, a total of 7 dust production points, equipped with 1 SLQM96-7 dust collector.
(4) Finished product screening tower workshop: 6 circular vibrating screens, feeding and discharging, a total of 21 dust production points, equipped with 3 SLQM128-7 dust collectors.
(5) The powder collected in the coarse crushing, medium and fine crushing workshops and dust collectors is transported to the screening tower through a belt conveyor, equipped with a 20 m3 air compressor unit.
(6) Finished product screening tower workshop: the powder collected by the dust collector is conveyed to the elevator through the belt conveyor and lifted to the powder tank.