Comprehensive treatment scheme for car dumper dust

During the process of dumping materials, a car dumper will generate a large amount of dust, which falls onto the moving parts of the car dumper, accelerating the wear of the rotating parts of the car dumper, causing jamming of the telescopic parts, and reducing the movement accuracy and service life of the related components of the car dumper;Large amount of dust reduces visibility, affects the operation of operators, thereby affecting production efficiency, and even causing accidents. In order to improve the ambient air quality of the dumper room environment, ensure the physical and mental health of employees, and ensure the safe operation of equipment, it is necessary to control the dust in the dumper system.

At present, the dust removal technologies used in the dumper system mainly include dry dust removal and wet dust removal. Dry dust removal is mainly used to remove coal dust from the belt guide groove at the material falling point below the tippler; Wet dust removal mainly suppresses the diffusion of dust above the funnel to the surrounding area during the unloading process of the dump truck. In order to overcome the shortcomings of using dry dust removal and wet dust removal separately, it is recommended to adopt a comprehensive dust removal method, which includes dust control, suppression, and dust removal, mainly including the isolation and sealing of dump truck dust, the application of intelligent sprinkler systems, the application of micron level dry fog dust suppression systems, and the application of dry dust removal systems.

1. Dust isolation and sealing of car dumper

The car dumper machine room has three floors, respectively for the feeding layer, funnel layer, and ground layer. Dust diffusion occurs to varying degrees in each layer, and different sealing and isolation measures have been taken to reduce dust diffusion.

1.1 Application of feeding layer buffer and anti overflow apron

During the feeding process of the tippler activation feeder, a large amount of dust is generated at the feeding point. There is a gap between the guide groove and the conveyor belt, and the dust will diffuse to the feeding layer through the gap. To control dust diffusion, it is necessary to control the gap between the guide groove and the tape. The buffer idlers are used at the feeding point of the conveyor below the tippler, and there is a distance between the two sets of buffer idlers. Each time the material is dropped, the tape between the two sets of buffer idlers will be impacted and sink, causing the gap between the tape and the guide groove to increase. In order to avoid gaps between the tape and the guide groove during each feeding, the buffer roller is replaced with a buffer, and the ordinary rubber plate is replaced with an anti overflow apron. The apron has one more sealing space than the ordinary rubber plate, which can greatly improve the dust prevention effect.

1.2 Sealing of the non overturned side of the funnel layer

There is a steel retaining wall on the overturned side of the funnel layer, and a inclined sliding plate on the non overturned side. However, the mechanism at the hanging cable and supporting wheel on the non overturned side is relatively complex and not blocked. Through on-site observation, the air inside the hopper is squeezed upwards by the material and discharged to the non overturned side of the hopper layer when the dumper starts unloading and tilts to around 100 °. The compressed air carries a large amount of dust from the hanging cable and supporting wheel to diffuse into the working environment of the hopper layer. Therefore, based on the operation trajectory of the hanging cable, a closed structure of the hanging cable was designed, with access doors left on the side of the structure to facilitate personnel entry for inspection and cleaning. The dust sealing structure at the supporting roller is similar to the structure at the hanging cable.

1.3 Installation of Ground Dust Baffles

When the tippler dumps materials, the rapidly falling material compresses the air inside the hopper, causing a rapid increase in air pressure inside the hopper leakage. Due to the locking effect of the activation feeder, the compressed air can only move upwards from the bottom of the hopper and drive the dust to quickly diffuse towards the ground layer, with a diffusion height of about 3m. After each unloading, a large amount of dust will fall off the ground. In response to this situation, dust shields should be installed around the tippler, with a height of 3.3m to prevent most dust from passing over the dust shield. In order to facilitate equipment inspection during operation, transparent windows that can be opened are installed on the dust baffle.

2. Intelligent sprinkler system

The intelligent sprinkler system mainly includes water supply pipeline system, moisture detection system, and intelligent control system. The water supply system pipeline is connected to the medium pressure dust removal pipeline in the feeding layer of the dump truck room. The main pipeline is equipped with butterfly valves, flow meters, filters, and pressure reducing valves. Each activation feeder is equipped with two branch pipes, each with a manual ball valve and electromagnetic valve. The two branch pipes are equipped with different numbers of nozzles, and the water supply can be adjusted in multiple levels. In order to achieve the effect of water mist dust suppression, the pressure at the nozzle should be reasonably controlled to ensure that the particle size of the water mist droplets sprayed from the nozzle is between 0.01mm and 0.05mm.

3.Micron level dry fog dust suppression system

When the dump truck is unloaded, the coal flows into the lower funnel and produces a large amount of coal dust, which quickly spreads to the top of the funnel and continues to spread. Micron level dry fog dust suppression system can produce fine water mist with a diameter of 1-10 μm, which can effectively adsorb coal dust suspended in the air, especially coal dust with a diameter of less than 10μm, so that the coal dust will be settled by gravity, thus achieving dust suppression effect and realizing dust suppression at the source.

4. Dry dust removal system

The suction port of the dry dust removal system is arranged on the material guide groove below the dumper funnel and the steel retaining wall above the funnel. The airflow containing coal dust is transported from the suction port to the dry dust collector through the dust removal pipeline for dust removal. The removed dust is returned to the belt conveyor below the dumper through a scraper conveyor, and a sprinkler nozzle is installed at the ash drop point to avoid dust raising at the drop point.

Due to the application of intelligent sprinkler systems, during the operation of the tippler, there will be no dust raised in the guide groove of the belt conveyor. However, when there is no coal flow on the funnel and belt, the use of the sprinkler system will cause water accumulation and coal sticking on the belt; If the dry dust removal system is started while sprinkling water, due to the high moisture content of the dusty airflow, it often causes the filter bag to stick and block. Therefore, the suction port at the guide groove of the dry dust removal system is interlocked with the intelligent sprinkler system. When the flow rate on the belt is lower than the set flow rate, the intelligent sprinkler system is stopped and the dry dust removal system is started; When the flow rate on the belt is higher than the set flow rate, turn on the intelligent sprinkler system and stop the dry dust removal system.

When the dump truck is unloaded, the induced wind is relatively strong, and the high-pressure induced airflow can only be discharged upwards from the funnel mouth. While carrying a large amount of coal dust and spreads above the working platform, affecting the working environment. The application of micron level dry fog dust suppression system has suppressed a lot of coal dust, but coal with large coal dust cannot be effectively suppressed. By setting dust suction ports on the steel retaining wall above the funnel, not only can a considerable amount of dusty airflow be sucked out for dust removal, but also the airflow pressure above the funnel can be reduced, thereby reducing the height of dust diffusion. Combined with the application of micrometer level dry mist dust suppression systems, dust can be more thoroughly suppressed.

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