Meitan xuebao (Oct 2023)
Multi-radial cyclone suction dust removal technology at coal mine belt transfer points
Abstract
The dust hazard and management at the belt transfer point is one of the most important issues in achieving efficient, safe and clean production in coal mines. To address the problem of dust pollution at the transfer point and to reduce the dust hazard at the transfer point, a multi-radial cyclone suction dust removal technology is proposed for the belt transfer point based on the cyclone suction theory. The technology is based on a certain number of inlets and jet angles on the side wall of the vertical drop pipe, with the suction outlet set above the drop pipe. The principle of operation is that the incoming air-flow from the side wall of the drop pipe changes direction when it meets the side wall and the inlet jets interact with each other to form an upward flowing cyclone in the drop pipe. A simulated 3D solid model and a test platform for multi-radial cyclone suction dust removal at the belt transfer point are built. A combination of numerical simulations and experimental tests is used to study the distribution of air-flow and dust transport in the transfer point. In the numerical simulation and experimental tests, eight air inlets are provided on each of the four-side walls of the drop pipe at an angle of 10° to the horizontal, and four-air inlets are provided on the guide chute, with the air inlets oriented tangential to the circle of the particle release position on the lower belt. According to the cyclonic suction theory, the greater the inlet air velocity on the drop pipe, the greater the pressure difference between the boundary of the drop pipe and the center, and the better the effect on dust collection. The simulation results show that the best inlet air speed for the multi-radial cyclone suction technology is 8 m/s, where the dust of less than 50 μm and the dust of less than 30 μm from the impact of the coal with the lower belt can be collected during the drop. Comparing the dispersion of the coal before and after falling in the test, it is concluded that the proportion of particles smaller than 50 μm in the coal on the lower belt is reduced by 47.96%, and the proportion of particles smaller than 5 μm is reduced by 44.62% after the application of the dust removal technology. It reduces the proportion of harmful particles in the coal. By measuring the dust concentration at the ends of the guide chute and at the inlet, the test determines that the best inlet air speed for the multi-radial cyclone suction dust removal technology is 8 m/s. At this time, the dust concentrations at the left and right ends of the guide chute and at the inlet are the lowest, and the dust removal efficiency is 97.71% and 99.92% respectively, and the overall dust removal efficiency at the transfer point can reach more than 95%. The study proves that the multi-radial cyclone suction dust removal technology at the transfer point can solve the problem of dust pollution , improve the working environment .
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