Single-stage AC electrostatic precipitation

Measurements are reported on the collection efficiency of a laboratory-scale single-stage electrostatic precipitator (3 cm plate spacing) excited by AC voltages (V/sub rms/ approximately 8 kV, f=20 to 500 Hz) biased to give no time-average. With f=60 Hz, an effective migration velocity of 3.5 cm/s is observed. Previously published works on the charging and migration of particles in AC coronas and on the effects of finite turbulent diffusivity on the precipitation process are combined to predict the experimentally observed dependence of the efficiency on the magnitude and frequency of the applied voltage. When applied to the experimental situation reported here, the model reduces to one of complete mixing, with the effective particle migration velocity being predicted in terms of the velocity that is achieved with DC charging and a charging time constant that is either estimated or obtained from charging experiments.<
>