| A lot of industrial dust had been produced from machining,metallurgical forging,iron ore mining and coal mining.Respirable dust is the main carrier of poisonous and harmful elements and hydrocarbon compounds because of the property of small particle size,high dispersion,large specific surface area,strong respiratory,spread wide,high chemical activity and adsorption capacity.The concentration of respiratory dust is too high,on the one hand it would easily damage humans respiratory organs;on the other hand even resulting in dust explosion accidents.Respirable dust prevention is significant for improving the human living environment and enhancing the level of industrial safety production.Gas-liquid two phase flow spray is an effective method for sedimentation of respiratory dust,but the effect of dust deposition is not clear.Determining the quantitative relationship between the efficiency and influence factors of gas-liquid two phase flow spray technology and optimizing the process parameters of gas-liquid two phase flow spray provide theoretical scientific guidance for the practical application.This article obtained the relationship between dust removal efficiency and influence factors by spray dust removal experiment in the self-designed experimental passage and make application study about settling PM 10 by gas-liquid two phase flow spray in haze environment.The atomization characteristics of the gas-liquid two phase flow nozzle is analyzed.The droplet size of Dv(90)is the smallest as 10.29 ?m when the air pressure is 0.3 MPa.When the air pressure is greater or less than 0.3 MPa,the distribution range of droplet size of Dv(90)is 15?50 ?m.Optimizing the size of droplets of gas-liquid two phase flow nozzle provides reference for studying relationship between spray dust removal efficiency and droplet size.This article analyzed the relationship between dust removal efficiency of gas-liquid two phase flow spray and the droplet size and spray volume.The dust removal efficiency is the highest with 89.60%when the droplet size is 10 ?m.In the case of the volume of spray is 168 kg/h,the dust removal efficiency reaches a critical value 90%.The effect of the gas-liquid two phase flow spray and the types and concentration of respirable dust on dust removal efficiency is also studied.The experiments show that the self-deposition efficiency was up to 87.10%when the concentration of respirable dust was 50 mg/m3.While the self-deposition efficiency was in the range of 9.09%to 18.18%at the case of the concentration of respirable dust was 18.33 mg/m3.The dust removal efficiency of gas-liquid two phase flow spray boosts as initial respirable dust concentration increases.When the initial respirable dust concentration was 20 mg/m3,the dust removal efficiency was over 90%.The dust removal efficiency of silica,graphite and fly ash by gas-liquid two phase flow spray was 77.09%,65.88%and 67.67%.In view of the PM 10 in haze environment,two phase flow spray system are designed and the experiments test are carried out subsequently.The experimental result shows that the deposition rate of PM10 can reach up to 80%.The experimental results not only accumulate experience for the application of gas-liquid two phase flow spray technology,but also provide a new technical means for PM10 control. |
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