Simulation study on dust emission and distribution characteristics of dust under the impact of coal flow at the transpersite of coal preparation plant

The transpersite in the coal transportation system is an important source of dust production in coal preparation plants. The coal produces a large amount of dust under the action of the drop of the transpersite, causing dust pollution and other problems. In order to inhibit the dust emission during the transfer process and explore the dust distribution characteristics to control dust pollution, based on the actual situation of a coal preparation plant, a three-dimensional structure of coal transpersite with equal proportion is constructed, and the dust diffusion process in the state of impinge and impact of coal flow is studied. Firstly, according to the similarity theory, a transpersite model test bench with a scale ratio of 3∶14 is constructed, and the wind field distribution characteristics of typical positions in the transfer process are studied. It is found that the wind speed on both sides of the wall in the height direction is high, up to about 6 m/s, while the wind speed in the middle and upper parts is low, and the simulation results are in good agreement with the experimental results, which verified the numerical simulation method and its related conclusions. At the same time, based on the CFD–DDPM method, considering the collision between particles, the dust impact and diffusion process under the impact of the transfer process is visually studied. It is found that there are a pair of vortices on both sides of the dust impact zone and its bottom area, which have a great influence on the dust distribution. The distribution of dust with different particle sizes in different regions is quite different. The concentration of dust in the closed side of the horizontal conveying section is as high as 9000 mg/m3, and this area needs to strengthen its sealing to prevent dust leakage. Based on Visual Basic, a post-processing program is developed independently, and the proportion of dust with different particle sizes in different regions is analyzed. It is found that the PM10–PM40 airflow follows well, and the PM50–PM100 deposition is significant. The dust removal scheme is designed for the area with high dust concentration to reduce the dust pollution, the suction fan is installed above the vertical blanking section, and the suction wind speed has a significant effect on the dust distribution in the vertical blanking section. When the suction wind speed is 15 m/s, the high-speed airflow promotes the dust to gather in the middle and upper regions, and the dust concentration is as high as 6 mg/m3, which provides theoretical guidance for optimizing the transfer structure and inhibiting the dust emission in the transfer process.