Experimental Study On The Mechanism Of The Fine Particles Separation By The Ultrasonic Nebulizer

Dusty gas emissions is the main source of atmospheric and respirable particulate matter.No matter traditional dust removal equipment or new compound dust removal equipment,the dust removal efficiency can reach more than 99%,but for particulate matter,especially PM2.5 the capture rate is low.A lot of PM2.5 discharged into the atmosphere can cause multiple lesions in the respiratory system,reproductive system,blood system and cardiovascular system,which extremely does harm to people's health.At the same time,PM2.5 has an serious impact on visibility,cloud and precipitation,acid precipitation,stratospheric and tropospheric chemical reaction,atmospheric radiation balance,photochemical pollution and fog,which causes serious environmental pollution.Summarized the existing efficient dust removal technology,such as electrostatic fabric filter,electrostatic granular bed filter,cyclone electrostatic precipitator,electrostatic humidifying dust catcher and wet electro-static precipitator can find that they are combined different dust removal mechanism with removing particulate matter.But according to B.Wang and other theories,as the particle size of particles is reduced,the fluid drag force into geometric multiples,far more than other field force,this become the main force of fine particles,which is the basic reason why fine particulate matter is difficult to removal.This paper summarizes the acoustic reunion reunited,magnetic,electric coagulation and reunited,chemical,steam phase change and so on the many kinds of pretreatment technologies for fine particulate matter together grow up.Give preference to select the low cost,simple equipment,the efficient vapor phase transformation technology from them and combined With simple structure,low cost,convenient operation,high temperature resistant,without being limited by the nature of the dust cyclone dust removal technology,composite the two dust removal mechanism to removal of fine particulate matter together.First of all,based on the experiment,this paper confirmed the effect of fine particulate matter removal of the combination of steam phase transition and cyclone dust removal technology.According to the Electro-acoustic Ultrasonic Nebulizer to obtain Vapor phase transformation,through the Electro-acoustic Ultrasonic Nebulizer to produce uniform dispersion of micron grade high density tiny droplets flow.Fine droplets can rapidly vaporized in the environment and water vapor condensing on fine particles after the environmental water vapor over saturation.According to the verification,this technology does can improve the removal efficiency of fine particles.Second,this paper summarized predecessors' theories,and then draws the atomized dust removal mechanism as follows:heterogeneous nucleation of condensation,Stephen flow transportation,collision together,fine particle surface characteristics change mechanism etc.Analysis of the process of fine particles reunion grew up can be divided into:(1)heterogeneous nucleation,Supersaturated vapor particles condense in fine particle and form critical size embryos;(2)the embryos condensed and grew.Condensed water vapor molecules diffuse to the surface of the embryo and impinge to bigger droplets;(3)by Brownian motion,turbulence and gravity,dust droplets continue to grow up.Analyzing the three processes can extract the following factors:1,the percentage of water vapor concentration and particle concentration;2,the contact time between water vapor and particles;3,the strength of water vapor condensation;4,collision strength.Finally,based on the science and feasibility and controlled experimental design principles,the experiment discussed the main mechanism of atomizing dusting.The experimental results showed that the strength of vapor condensation strength and the percentage of water vapor concentration and particle concentration are the main influencing factors of particle concentration reunion grew up.Through the study of above contents,this article provide theoretical basis for the vapor phase change,combined with the technology-cyclone in addition to the new composite dust removal technology,and provide the experimental operation support for its popularization and application.