Experimental Study On The High Efficiency Spray And Dust Removal In Coal Mine

Braize is one of the most important threat in coal mines,once it explodes,a lot of casualties and huge economic losses will be caused,besides,long-term inhalation of respiratory dust can cause pneumoconiosis.Although spraying is the most commonly method in dust setting,at present,its effect in coal mine is pretty poor,especially for the respirable dust has a very low efficiency,so aiming at improving spraying technology and studying the wettability of coal,which are significant to improving the working environment under mine,and guaranteeing the safety in coal production.The paper mainly studied the following three aspects:(1)In this paper,the wettability of surfactant and coal dust is studied from three aspects of surface tension,contact angle and sedimentation experiment.A high anionic electrolyte was added to the surfactant solution(Na2SO4),and then,made a determination of surface tension,we could see that the addition of a high anionic electrolyte to the surfactant solution could improve the wetting capacity of the surfactant solution;we measured the contact angle on different sizes of coal powder,find that there are difference among different sizes of coal powder,the smaller size it was,the larger contact angle was,that proved a worse wettability of coal;meanwhile,by measuring the contact angle on different kinds of coal,we found that wettability got worse with the rise of ash content.By measuring the contact angle and sedimentation experiment,we found that all four surfactants could wet coal dust,and OP-10 had a best wettability at a mass concentration of 0.005%.(2)In order to analyze the characteristics of gas-water spray in coal mine,Based on self-designed gas-water spray test platform,we studied the spatial distribution and influencing factors of air atomization nozzle flow characteristics and atomization particle size with the help of electromagnetic flowmeter,air mass flowmeter and Malvern real-time high-speed spray particle size analyzer.And also compared gas-water mixing nozzle and conventional spiral nozzle,found that using gas-water mixing nozzle could get the same D[3,2] at a lower water pressure and air pressure,in contrast,using conventional spiral nozzle to get the same D[3,2] needs a very high pressure,that meant a higher water consumption and more economic cost.At last,we studied the influence to atomization spray characteristics by adding surfactant,found that atomized particle size reduced slowly with the rise of concentration,when the concentration of solution got to cmc,D[3,2] would rise withthe increase of concentration.(3)Based on the self-designed experimental platform for the performance of the dust setting in coal mine,the influencing factors of the dust spray efficiency of the nozzle were studied by using the experimental method.By comparing dust setting efficiency of gas-water mixing nozzle and conventional spiral nozzle aimed at all dust and respirable dust when adding surfactant or not,found that these two nozzles both have a better dust setting efficiency at a best spray characteristics,and gas-water mixing nozzle had a better efficiency than conventional spiral nozzle.After adding surfactant,gas-water mixing nozzle had a better dust setting efficiency to all dust and respirable dust,the efficiency rised with the rise of concentration,when the concentration got to cmc,the rate of increase in dust setting efficiency slowed down with the addition of surfactants.In summary,the gas-water mixed spray can enhance the droplet surfactant,improve the atomization effect and improve the efficiency of dust reduction,and provide reference for further research.