Research On Dust Pollution Control Of The Trestle Type Coal Storage Yard

The trestle type coal storage yard is widely applied in coal industry because of the advantages of simple structure,less investment,small influence by the engineering geological condition and so on.To solve the problem of serious dust pollution in the process of coal unloading,a new dust control system was proposed.The system is mainly composed of mobile spraying dust removal device and spray and immersion dust collector.The system has advantages of small water consumption,low operating costs,good dust removal effect and easy maintenance.The system will improve working conditions of workers and reduce the waste of coal resources.Experiments were carried out on the laboratory spraying dust removal model to simulate the internal dust removal of the mobile cover.The experimental results indicated that with the increase of spraying pressure,the spraying particle size tends to decrease and the spraying flow rate tends to increase for the same type of nozzle.Reducing the wind speed inside mobile cover model can improve the collection efficiency,the collection efficiency increased from 74.29% to 81.52% when the speed decreased from 0.4m/s to 0.1m/s.Increasing coal moisture content can improve the collection efficiency,the collection efficiency increased from 76.64% to 82.11% when the coal moisture content increased from 0% to 3%.The removal efficiency tends to be lower when the particle size is smaller,the collection efficiency decreased from 76.64% to 65.08% when the particle size decreased from 46.17?m to 17.03?m.The numerical simulation on the flow field and the water droplet distribution of the spray and immersion dust collector was carried out by CFX software.The simulation results indicated that the collection efficiency of cone tube was higher than the cylinder tube.The flow field distribution was uneven in the lateral inlet structure spray and immersion dust collector,and the standard deviation of gas mass flow of tube outlets was 1.39.The flow field was well-distributed in the top inlet structure spray and immersion dust collector,and the standard deviation of gas mass flow of tube outlets was 0.20.Also the distribution of the water droplet in the top inlet structure spray and immersion dust collector was more evenly distributed than the distribution of the lateral inlet structure spray and immersion dust collector.Comparative experimental study on the dust collecting properties of the two different inlet structures was done,the results indicated that compared to the lateral inlet structure spray and immersion dust collector,the emission concentration of top inlet structure decreased by 8.29?15.75mg/m~3 and the collection efficiency increased by 0.83%?1.57% when the airflow was 1000m~3/h,the inlet dust concentration and the height of water level was above 0mm(including 0mm)on the condition of no spraying.The emission concentration of top inlet structure spray and immersion dust collector was only 3.80mg/m~3,and the collection efficiency was 99.62% when height of water level was 0mm on the condition of spraying.