To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collec...To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.展开更多
In order to reduce the environmental smog caused by coal combustion,air pollution control devices have been widely used in coal-fired power plants,especially of wet flue gas desulfurization(WFGD)and wet electrostatic ...In order to reduce the environmental smog caused by coal combustion,air pollution control devices have been widely used in coal-fired power plants,especially of wet flue gas desulfurization(WFGD)and wet electrostatic precipitator(WESP).In this work,particulate matter with aerodynamic diameter less than 10μm(PM_(10))and sulfur oxides(SO_(x))have been studied in a coal-fired power plant.The plant is equipped with selective catalytic reduction,electrostatic precipitator,WFGD,WESP.The results show that the PM_(10)removal efficiencies in WFGD and WESP are 54.34%and 50.39%,respectively,and the overall removal efficiency is 77.35%.WFGD and WESP have effects on the particle size distribution.After WFGD,the peak of particles shifts from 1.62 to 0.95μm,and the mass concentration of fine particles with aerodynamic diameter less than 0.61μm increases.After WESP,the peak of particle size shifts from 0.95 to 1.61μm.The differences are due to the agglomeration and growth of small particles.The SO_(3)mass concentration increases after SCR,but WFGD has a great influence on SO_(x)with the efficiency of 96.56%.WESP can remove SO_(x),but the efficiency is 20.91%.The final emission factors of SO_(2),SO_(3),PM_(1),PM_(2.5)and PM_(10)are 0.1597,0.0450,0.0154,0.0267 and 0.0215(kg·t^(−1)),respectively.Compared with the research results without ultra-low emission retrofit,the emission factors are reduced by 1~2 orders of magnitude,and the emission control level of air pollutants is greatly improved.展开更多
文摘To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.
基金The work was supported by the National Key Research and Development Plan of China(No.2016YFB0600605).
文摘In order to reduce the environmental smog caused by coal combustion,air pollution control devices have been widely used in coal-fired power plants,especially of wet flue gas desulfurization(WFGD)and wet electrostatic precipitator(WESP).In this work,particulate matter with aerodynamic diameter less than 10μm(PM_(10))and sulfur oxides(SO_(x))have been studied in a coal-fired power plant.The plant is equipped with selective catalytic reduction,electrostatic precipitator,WFGD,WESP.The results show that the PM_(10)removal efficiencies in WFGD and WESP are 54.34%and 50.39%,respectively,and the overall removal efficiency is 77.35%.WFGD and WESP have effects on the particle size distribution.After WFGD,the peak of particles shifts from 1.62 to 0.95μm,and the mass concentration of fine particles with aerodynamic diameter less than 0.61μm increases.After WESP,the peak of particle size shifts from 0.95 to 1.61μm.The differences are due to the agglomeration and growth of small particles.The SO_(3)mass concentration increases after SCR,but WFGD has a great influence on SO_(x)with the efficiency of 96.56%.WESP can remove SO_(x),but the efficiency is 20.91%.The final emission factors of SO_(2),SO_(3),PM_(1),PM_(2.5)and PM_(10)are 0.1597,0.0450,0.0154,0.0267 and 0.0215(kg·t^(−1)),respectively.Compared with the research results without ultra-low emission retrofit,the emission factors are reduced by 1~2 orders of magnitude,and the emission control level of air pollutants is greatly improved.
