| During the control process of particulate air pollution,electrostatic precipitator(Electrostatic precipitator,ESP)stands out among many dust removal equipment and has been widely applied in industrial production due to its high efficiency,large capacity,convenient maintenance and economic benefits.In recent years,based on continuous improvement and optimization of precipitator,many experts and scholars has developed many new types of electrostatic precipitator,among which the transverse polar plate electrostatic precipitator and electrostatic precipitator with wide space proved to have good removal performance and economic benefits.In view of the low collection efficiency for ultra-fine dust and high energy consumption of traditional electrostatic precipitator,combined with the advantage of both transverse-plate electrostatic precipitator and electrostatic precipitator with wide space,through improving and optimizing electrode configuration design,new type wide-space collecting-plate ESP was designed on the basis of previous studies.FLUENT in CFD software was used to simulate the continuous phase flow field distribution,discrete phase motion characteristics and dust removal efficiency of the new type double-vortex plate ESP.Based on the results of theoretical research and numerical simulation,the main part of the industrial-scale device of new type wide-space double-vortex collecting plate ESP with 50000m3/h capacity was designed and selected.The main contents and conclusions of this paper are as follows:(1)Theoretical research and structural design: In this paper,based on the research on the dust removal mechanism and research progress of Single-stage Double-vortex Plate ESP,a new type double-vortex collecting plate ESP model was established: double-vortex collecting plates were arranged in the direction perpendicular to the air flow inside the ESP.Star-shaped coronas were put both in front of each collecting plate and in the middle of plate gap.Based on predecessors' research results on the wide spacing collecting plate,a wide gap between the collecting plates was adopted.(2)CFD numerical simulation: CAE software PTC Creo 3.0 was used to establish the three-dimensional geometric model of the research object.Ansys ICEM software was used to mesh the built three-dimensional geometric model.FLUENT software was used to simulate the continuous and discrete phase of the new type double-vortex collecting plate ESP.The results of numerical simulation showed that the new type wide space double-vortex collecting plate ESP had the advantages of high efficiency and low energy consumption.a.Simulation results of the continuous phase showed that the pressure loss inside the new type double-vortex collecting plate ESP was smaller,so that the energy consumption of the dust collector is relatively low;Simulation results of continuous phase flow distribution showed that,the structure of this type of collecting plate can make the dust-laden air flow in the vicinity of the collecting plate form vortex turbulence,especially in the leeward area,can form a basic symmetrical double vortex structure;when the dust laden air flow in,there would be a good formation of high and low speed in the field,the high speed in the collecting plate gap was conducive to improving the ion momentum of charged particles and reduce ion composite,in turn improve the transport rate of particles.The low speed near collecting plate was favorable for charged particles moving to collecting plate,and can effectively curb the secondary dust;b.Discrete phase simulation results showed that the residence time of particles in the electricfield I this ESP can effectively extend,and in turn reduce the required field length and cost.When the particles' average velocity was 3m/s,the discrete phase particle residence time in the dust collector can reach 6S,which was 2~3 times of the average computation time in other traditional ESP;c.The simulation results of collecting efficiency of particle in size of 0.1 ?m,0.5?m,1?m,2.5?m,5?m and 10?m showed that,when no external voltage was applied,this type of ESP also had the function of dust collection: when the dust velocity was 2m/s,the particle size increased from 0.1?m to 10?m,removal rate increased from 39.9% to 54.2%;while the dusty flow velocity was 3m/s,dust removal rate increased from 37.58% to 47.75%;d.Dust removal efficiency increased with the increase of particle size and applied voltage.When flow velocity was 3m/s,the particle size is 1?m,the applied voltage increased from 0kV to 70 kV,and the trapping efficiency can be increased from 37.58% to85%.When the particle size was 2.5 ?m,when the applied voltage increased from 0kV to 70 kV,the trapping efficiency can be increased from 44.17% to 97%.When the particle size was 10 m,the applied voltage increased from 0 kV to 70 kV,the trapping efficiency could reach 100%.(3)The design of industrial-scale test equipment: based on the analysis of numerical simulation results,a 15000Nm3/h processing capacity new type double-vortex collecting plate ESP industrial-scale test equipment was designed.High voltage power supply,air distribution device,corona pole system,dust collecting system and ash cleaning system were calculated or selected.It provided a good theoretical basis for the industrial application and further study of the new type double-vortex collecting plate ESP. |
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