| Coal mining is always accompanied by serious dust pollution problems.As one of the five major disasters in coal mine,dust pollution will pollute the underground production environment and affect the normal operation of coal mine production activities.More importantly,it will threaten the health of operators and lead to the occurrence of pneumoconiosis.Water bath dedusting technology is a kind of wet dedusting technology with simple structure and low installation and maintenance cost.The dust removal technology combined with spray and string filtration has better dedusting effect,especially the respirable dust can be effectively purified.However,the air volume and efficiency of water bath dust removal are unstable,and a single water bath dust removal can not meet the higher and higher requirements of occupational health on the working environment.The dust collecting ability of the spray chordal grid will decrease when the dust concentration is high and the air volume is large.Through the analysis and summary of the theory and experimental research of water bath dust removal technology,spray dust suppression technology and string grid water film dust catching technology,it is found that most of the researchers have little research on the factors affecting the dust removal performance of water bath dust removal combined with water bath duster.Therefore,based on the technology of water bath and dust removal,combined with the technology of water spray and dust collection,we study a composite dust collector and start the following research contents:(1)Based on the dedusting conditions of fully mechanized coal mining face,the advantages and disadvantages of the current wet dust catcher are compared based on the water bath dust removal,spray dust reduction and grid water film dust catching technology.The water bath dust removal is used as a primary dedusting,and the droplet dripped by the wind is used as a part of the spray film in the grid to strengthen the combination of dust and water.(2)The three-dimensional physical model is established according to the designed size of the dust removal device by using the three-dimensional modeling software.The gas-liquid two-phase flow in the internal flow field of the water bath section of the dust removal device is numerically simulated by using the hydrodynamic software,the distribution law of the internal flow field of the dust removal device is obtained,and the distribution of droplet concentration,pressure and velocity in the device is analyzed.(3)The experimental platform of water bath string grid water film composite dust removal device is built.Combined with numerical simulation and experimental analysis,the structure of dust removal device is optimized.Measure the system resistance of the water bath section of the dust removal device when the air volume is different and the air duct is immersed in the water surface.Optimize the experimental working condition range,and select the working condition range suitable for water bath dust removal.Then measure the dust removal efficiency under single water bath working condition,analyze the distribution change of dust particle size before and after dust removal by using dust particle size analysis equipment,and calculate the respiratory dust removal efficiency of water bath dust removal under different working conditions.(4)On the basis of the best water bath dust removal conditions,the grid and spray were added to the dust removal device to measure the dust removal efficiency of the whole dust and respirable dust.The experimental results showed that the optimum dust concentration was17.5600 mg/m~3 at the outlet,and the dust concentration at the outlet decreased to 5.1250 mg/m~3after the increase of the string grid.The dust concentration decreased to 70.81%at the outlet,and the dust concentration at the outlet of the chill grid decreased to 1.2500 mg/m~3,which was reduced by 92.88%.It is 5 mg/m~3 lower than the national management limit of exposure concentration in coal mine workplaces. |
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