Research On Flow Uniformity And Pressure Characteristics Of Electrostatic Precipitator

As the voice of the environmental protection has increased,the Chinese government has also made a lot of relevant efforts,including setting increasingly strict pollutant emission standard,encouraging technical innovation in environmental protection,strongly supporting energy saving and environmental protection industry and so on.Electrostatic precipitator(ESP)with its advantages of large treating capacity,high dust removal efficiency,wide adaptation,low operating costs,has always been the main force of pollutant control equipment.However,with changes of coal used which has more ash and viscosity along with more and more stringent requirements on pollutant emission in recent years,how to improve the removal efficiency and reduce particle emissions more economically and effectively has drawn an increasing number of researchers' attention.The air flow distribution is one of the most important factors that affect the ESPs' performance.In the previous research work,researchers often used perforated plates with single porosity which is on one hand only for small extending angle precipitators,on the other hand lack of detailed study of resistance characteristics of perforated plates and ESPs.Aiming to adjust uniformity of air flow,various non-uniform porosity perforated plates were optimized designed and a physical model was set up.In order to study resistance characteristics of perforated plates,experimental rig of perforated plate was also set up.The main research work is as follows:Firstly,experiment of air flow in the ESP model was carried out.This paper made a relevant physical model which took the ESP of some a 2x300 MW power plant as prototype.A variety of perforated plates with non-uniform porosity were designed and optimized in order to investigate the flow uniformity in the condition of without plates,adding different perforated plates with non-uniform porosity.Secondly,the resistance characteristics of perforated plates and ESP model were investigated.The influence of different porosity,Reynolds,relative thickness on resistance characteristics was studied and a piecewise expression was proposed to estimate resistance coefficient.Then,the effect of distribution of porosity and number of layers on the pressure characteristics was studied in the physical model.Finally,numerical simulation of the whole flow field of the ESP was carried out including the gas flue's and body's part.The result of physical model test and the pressure drop test of perforated plates were used to revise the numerical simulation model.Although there is a little deviation between the final simulation results and physical model results,they are coincident in the trend of velocity distribution.What's more,simulation which can predict the velocity distribution well has positive guiding significance in the design of perforated plates.