The Research On Charge Characteristics Of Solid Particles Under Atmospheric Pressure

China’s energy structure determines that the pattern of coal combustion as the main form of energy will not change in the near future,the massive burning of coal has led to a sudden increase in the emission of solid particles in the atmosphere,causing a series of ecological problems,including haze,which greatly affects the basic social life of human beings,how to reduce the emission of such particles,as well as the effective collection of already emitted particles is increasingly concerned.Electrostatic precipitation technology based on low temperature plasma has traditionally been used mainly in the dust removal systems of large installations such as power plants,but in recent years it has also been gradually applied in household air filtration systems due to its high efficiency,convenience and low wind resistance.For such devices,it is a proven method to increase the average particle charge of pollutants and thus increase the driving velocity in the charged area.The purpose of this paper is to investigate the effective way to increase the charge of solid particles by studying the charge of solid particles in corona discharge under different conditions.In this paper,a literature review of existing particle control technologies and plasma technology is conducted,and an experimental platform is designed and built independently to perform multi-dimensional simulations of particle charge characteristics to clarify the electric field distribution inside the charge machine,the space charge density distribution,the motion trajectory of particles and the collection efficiency of particles of different particle sizes.The average charge,number density and mass density of the particles on both sides of the charger were measured in real time using electrical low Pressure impactor(ELPI+)and an aerosol spectrometer,and the effects of the electric field nature in the charging region and the change of the discharge parameters of the composite drive form on the charge of the particles were investigated.The results show that under the same voltage amplitude,the charge amount of the pulse-driven form is much higher than that of the DC-driven form;in the particle size region smaller than 0.1 μm,the average particle charge amount of the composite driven form is about 3 times higher than that of the single power-driven form.In the average particle charge curve of the composite drive form,the pulse drive form plays a dominant role;under the pulse drive form,the average particle charge increases with the increase of discharge frequency and the increase of electrode number.In the experimental platform of particle charging characteristics,the parameters of charge voltage,electrode spacing,electrode form,flow rate and particle type were changed,and the results showed that: under the same conditions,the average particle charge was higher in the mansard form than in the wire plate form,and the charge increased slightly with the increase in the number of mansard poles;with the increase in flow rate,the dust removal efficiency of solid particles decreased abruptly;with the increase in particle size,the flow rate and the dust removal efficiency changed more linearly.With the increase of particle size,the change law of flow rate and dust removal efficiency is closer to linear;the type of particles also affects the average particle charge and dust removal efficiency.In this paper,we innovatively propose multiple electrodes composite drive charging form,which can improve the average charge of difficult to charge small particle size particles to about3 times compared with the DC corona charging form,which can effectively improve the collection efficiency of small particle size particles,and thus further improve the overall collection efficiency of polluting particles such as PM2.5.