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
Aggregation of fine ash into larger particles benefits fly ash removal in an electrostatic precipitator.Thermal aggregation,turbulent aggregation,and electrical aggregation of fine ash (derived from co-firing of bioma...Aggregation of fine ash into larger particles benefits fly ash removal in an electrostatic precipitator.Thermal aggregation,turbulent aggregation,and electrical aggregation of fine ash (derived from co-firing of biomass fuel and anthracite coal) was simulated under different conditions in an electrostatic precipitator.A population balance model and user-defined function in Fluent were assumed to obtain aggregation kernel functions and calculate the aggregation effects on the co-combusted particles.The results show that electrical aggregation had an obvious effect on both micron-and submicron-sized particles.For submicron particles,the effect of thermal aggregation is about ten times greater than turbulent aggregation.Meanwhile,for micron-sized particles,turbulent aggregation is about seven times greater than thermal aggregation.Therefore,particle aggregation in the electrostatic precipitator mainly occurs because of electrical aggregation,supplemented by thermal aggregation and turbulent aggregation.When the flow velocity is 1.0 m/s,particle volume fraction is 1.4%,and biomass co-firing ratio is 10%,the effects of all three aggregation processes on ash particles are optimized.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 National Natural Science Foundation of China(Grant No.51376063).
文摘Aggregation of fine ash into larger particles benefits fly ash removal in an electrostatic precipitator.Thermal aggregation,turbulent aggregation,and electrical aggregation of fine ash (derived from co-firing of biomass fuel and anthracite coal) was simulated under different conditions in an electrostatic precipitator.A population balance model and user-defined function in Fluent were assumed to obtain aggregation kernel functions and calculate the aggregation effects on the co-combusted particles.The results show that electrical aggregation had an obvious effect on both micron-and submicron-sized particles.For submicron particles,the effect of thermal aggregation is about ten times greater than turbulent aggregation.Meanwhile,for micron-sized particles,turbulent aggregation is about seven times greater than thermal aggregation.Therefore,particle aggregation in the electrostatic precipitator mainly occurs because of electrical aggregation,supplemented by thermal aggregation and turbulent aggregation.When the flow velocity is 1.0 m/s,particle volume fraction is 1.4%,and biomass co-firing ratio is 10%,the effects of all three aggregation processes on ash particles are optimized.
