Study On Dust/Fog Fine Particles Removal Technology Through Pre-charging Agglomeration Coupled With Electrostatic Precipitator

Unorganized emissions of dust and fog particles often occur in industrial production processes,causing serious harm to human health and the environment.As the most commonly used technology to remove particulate matter,electrostatic removal technology still has many problems and limitations in the process of dust and fog removal.In order to improve the adaptability of electrostatic removal technology in the process of dust and fog removal based on the advantages of pre-charging in promoting the increase of fine particle agglomeration and improving the initial charge of fine particles,this paper proposed electrostatic removal technology based on pre-charging agglomeration of dust and fog particles,and the experimental system of dust/fog fine particles pre-charging agglomeration coupled with electrostatic precipitator was built.Combining with theoretical calculations and numerical simulation analysis,the performance of the involved shielding mesh type pre-chargeing device,fine particle charging,agglomeration and removal characteristics,etc.wree studied in depth,the main research content and conclusions are as follows:The force analysis of the particles accumulated on the surface of the discharge electrode verified the necessity of adding the shielding mesh to the pre-chargeing electrode during the agglomeration process.The experimental study showed that the pre-charging performance of the pre-charging device for fine particles could be maintained more effectively with the addition of the shielding mesh.The pre-charging amount of particles was positively correlated with the pre-charging voltage and particle size.The single particle charge of fog particles.dust-fog mixed particles and dust particles was reduced in order because of their own charging properties.For this experiment,the existence of the potential on the shielding mesh inhibited the discharge of the pre-charging electrode on the one hand,and promoted the movement of the generating electrons to the pre-chargeing zone on the other hand.Therefore,the optimal shielding mesh resistance existed in the experiment,which was selected to be 200 MΩ by comparing the particle charging and agglomeration effects.The charge mixing in the pre-treatment zone promoted the collisional agglomeration of fine particles.The agglomeration efficiency of the fog particles was higher than that of the dust particles and dust-fog mixed particles because of the strong charging capacity.It was proved that the increase of pre-charge voltage and the decrease of wind speed were beneficial to the increase of fine particle agglomeration efficiency.while the change of concentration had no significant effect on the agglomeration efficiency.This was due to the fact that an increase in particle concentration increased the collision probability while weakening the single particle charge.Combining the trends of charge and agglomeration efficiency,it could be found that the particle charge contributed to the overall agglomeration efficiency,but does not play the only decisive factor.The numerical simulation proved that the particles were driven by the electric field force to move along both sides of the corona pole toward the collection plate,and the particle trajectory simulation was basically consistent with the experimental results.The results showed that the removal efficiency was positively correlated with the removal voltage and negatively correlated with the wind speed.but the change in the removal pattern due to the change in concentration was different.As shown in that for the fog and dust-fog mixed fine particles.the removal efficiency did not change significantly with the change of concentration;The removal efficiency of the fine dust particles decreased with the increase of concentration,which was closely related to the characteristics of particle charging motion and the corona ionization performance of the discharge electrode.These phenomena were closely related to the charge motion characteristics of the particles and the corona ionization properties of the discharge electrode.By comparing the mass concentration of solid particles in different particle removal conditions,it was found that the electrical environment was favorable for the co-removal of dust-fog mixed particles.For high removal voltages,pre-charging did not significantly improve electrostatic removal efficiency,but effectively reduced the electrostatic removal voltage and overall power consumption while achieving equivalent removal.At the combined voltage of[60 kV for pre-charging and 35 kV for electrostatic removal].the equivalent removal voltages were reduced by up to 10 kV(18.2%)and 9 kV(16.4%)for the conditions of "droplet concentration of 2000 mg/m3" and mixed particle concentration[200 mg/m3 for dust and 2000 mg/m3 for fog],respectively.16.4%)and the power consumption was reduced by 9.9 W(27.3%)and 9.4 W(25.5%),respectively.The study designed a pre charging device for shielding mesh that can stably and efficiently discharge.The article explored the agglomeration and the efficiency enhancement of electrostatic removal of particles by pre charging device,proved that device can effectively improve the electrostatic removal environment improve electrostatic removal efficiency,and reduce energy consumption.The study provided an useful reference for the optimization design of dust/mist particles in the industrial application of electrostatic removal.