Study On Dedusting Technology By Gas-liquid Two-phase Flow Spray: Crucial Factors And Their Engineering Application

A significant amount of dust will be produced when working under the coal mine,which contains respirable dust with the characteristics of small particle size,high dispersion and easy absorption.And it will accompany breathing into the lungs.Breathing in this high concentration environment for a long time will cause irreversible damage to the lung.Spray dust falling technology is widely used in dust falling.The most common one is the high-pressure dust-settling technology by spray.The water mist formed by this technology has a good settling effect for large particle dust,but it has poor collection efficiency for respiratory dust with small particle size.The study found that the water mist formed by the gas-liquid two-phase flow spray technology has a particle size close to that of respirable dust and has an efficient falling effect on respirable dust.It is currently widely recognized as an efficient atomization dust falling technology.However,there are still some deficiencies in the research of atomization mechanism and influencing factors.And this paper will conduct in-depth experimental research on it.First,this paper will introduce in detail the construction of high-pressure spray experimental platform from the overall framework of the platform,the layout of spray units and the choice of instruments and equipment.The experimental platform is built in the largest dust removal channel in the country at present,with a cross-section of4m~2,which makes the experimental environment closer to the real tunnel.The purpose of the platform is to compare the advantages and disadvantages of the high-pressure spray dust falling technology and the gas-liquid two-phase flow spray dust falling technology.Another important link in the spray system is the nozzle.As the main body of spray formation,the spray effect will directly affect the experimental results.Fluent fluid simulation was carried out for the nozzle used in the experiment.The spray atomization process was analyzed by observing the factors affecting the particle size of the spray,such as gas water volume ratio and flow velocity in the cavity.And it was also used as the standard for nozzle process parameter optimization.Then the particle size measurement of the nozzle was calibrated.It was found that when the pressure was 0.25MPa,the particle size was the smallest and the uniformity was good.And the average value of the spray particle diameter D50 was 18?25?m.When the pressure was less than 0.25MPa,the particle size was 32?96?m,but the lower the pressure,the more uneven it is.After determining the spray particle size,the influencing factors of the dust reduction rate were studied.First,according to the previous calibration data,test the dust removal rate at different spray particle sizes.Among them,the large particle water mist is provided by the high-pressure spray system.The results show that the smaller the water mist particles,the higher the dust removal rate,up to 72.52%.25?m.Then study the influence of the spacing between the spray unit supports on the dust removal rate.The main purpose is to solve the problem of mutual collision consumption between sprays.The result is that when the bracket spacing is greater than 2m,the collision between water mists is almost eliminated.Finally,studying the relationship between the number and position of the nozzles on each spray unit and the dust removal rate.The results show that the installation of 4 nozzles in each row of supports is the best,and the position at the top or both sides of the support has little effect on the dust removal rate.In order to verify the previous basic experiment on the relationship between spray particle size and dust removal rate,a high-pressure spray dust reduction and gas-liquid two-phase flow spray dust reduction engineering experiment was conducted on the site of the Halagou Coal Mine of Shendong Group.And a specific experimental plan was designed according to the site.The experimental results show that the dust removal rate of each test point increases by 26.4%?58.1%compared with the original high-pressure spray system when the gas-liquid two-phase flow spray system is turned on.The engineering experiment results are consistent with the simulation results in the laboratory.