Study On The Characteristics And Influencing Factors Of Coal And Rock Cutting Dust Generation In Fully Mechanized Mining Face

Mine dust is one of the most serious hazards in coal mine production.Approximately 15,000 new patients are infected with pneumoconiosis due to inhalation of mine dust each year.The large-scale implementation of coal shearers has significantly improved the level and efficiency of coal mining machinery.However,the concentration of flour dust in fully mechanized mining has risen sharply.In order to control the high concentration of dust in fully mechanized mining faces,in recent years,many domestic and foreign dust control technologies such as spray,foam,dust removal fans,dust barrier air curtains and other matching coal mining machines have been developed at home and abroad.Researchers mostly pay attention to the improvement of the technical parameters of dust suppression equipment.The research on the source of dust generation,shearer cutting and crushing coal and rock is very weak,the rules of dust generation and rules are not clear,and the dust concentration of different coal mining machines may vary greatly.Due to the lack of consideration of the differences in dust generation locations and coal and rock,the selection and implementation of dust prevention measures lack scientific basis.The mismatch of dust reduction effect and dust generation intensity results in poor dust reduction effect or redundant usage,resulting in unreasonable technology and economy.In order to solve the above problems,the paper adopts a comprehensive research method combining theoretical analysis,laboratory experiment and numerical simulation to systematically study the coal dust generation mechanism of the shearer drum pick and the influence of the physical and chemical properties of coal on cutting and crushing..The main results and conclusions achieved are as follows:After studying the research of domestic and foreign scholars on the shearer drum cutting and crushing coal and rock,the impact of the mechanical properties of the drum on the cutting and crushing is analyzed.Reeves's theory is used to explain the breaking mechanism of coal and rock,and the friction between coal rock and coal rock,and the friction between the pick and coal rock should be considered when establishing the cutting mechanics model.A single tooth rotary cutting mechanics model is established and obtained The calculation formula of single tooth rotation cutting resistance.According to the working status of the shearer,explore the movement trajectory of the drum picks,and further establish the mechanical model of the drum cutting homogeneous coal,and obtain the drum cutting load under the condition of the homogeneous coal seam,which provides a theoretical basis for subsequent experimental research.The shearer cutting head rotates to cut coal and rock is a complex and discontinuous force process.This article designs the size and mechanical parameters of the drum under the actual working conditions of the shearer,and based on similar simulation coefficients.Simulate the actual drum cutting head cutting and crushing coal and rock system,which includes variable frequency motor,drum cutting head,cross slider,coal block fixing device,transparent closed cover and other devices assembled.The entire test process is carried out in a sealed enclosure to prevent dust from bursting out and affecting the dust collection effect.The CCZ-20A dust sampler is used to collect the dust in the air,and the dust particles that are broken from the coal are collected and sieved.Dust below 250um is dried for dust particle size test.The dust collected by the dust sampler is processed to obtain the dust concentration in the average time.The four coal samples of Guqiao,Xinji,Xieqiao and Kouzidong are subjected to firmness coefficient and industrial analysis to obtain the firmness of the four coals.The basic parameters such as coefficient,moisture,carbon content,density,ash content and volatile content are studied.The influence of the physical properties of coal on the dust concentration and particle size is studied.The conclusion is as follows:The solidity coefficient of coal has a negative correlation with dust generation.Relationship,the greater the solidity coefficient of coal,the smaller the proportion of coal dust concentration and the cumulative dust particle size,the coal's own moisture will inhibit the dust,the higher the moisture content,the cumulative proportion of respirable dust and PM2.5 dust The lower the value,the lower the dust concentration;the cumulative proportion of PM2.5 dust and respirable dust and the dust concentration decrease with the decrease of the fixed carbon content,which exactly shows that the fixed carbon content has a positive correlation with the effect of dust generation;volatilization There is a certain negative correlation between ash and dust generation,but the correlation is weak;ash content basically has no effect on dust generation characteristics.The total load value of the Guqiao coal sample is less than the total load value of the Xinji coal sample and the Xieqiao coal sample,and the total load value of the Xinji coal sample and the Xieqiao coal sample are not much different.Guqiao,Xinji and Kouzi The total load value of the East coal sample is less than that of the Kouzidong coal sample.According to the test results,the Guqiao coal sample has the largest cumulative proportion of dust concentration and dust particle size,and the Kouzidong coal sample has the smallest cumulative proportion of dust concentration and dust particle size.The research results of this paper provide theoretical support for correctly understanding the characteristics of cutting and crushing dust produced by the shearer drum cutting head under actual working conditions,enriching the in-depth understanding of the law of dust generation,and providing important guidance for actual dust reduction and protection.Figure[51]Table[7]Ref.[81]...