Modelling of the effect of electrode geometries on the corona discharge current-voltage characteristic for wire-plate electrostatic precipitators

An electrostatic precipitator (ESP) operates on the principle of electrostatic separation of dust particles after charging, hence high ion density and electric fields are required. Therefore, the corona discharge current-voltage characteristic is very important and depends on several factors: discharge electrode shape, dimensions and surface condition, gas flow properties, dust particle loading and space charge, polarity of applied voltage, etc. We present a model for the prediction of the current-voltage characteristic and experimentally validate it for round, threaded, rectangular and rigid discharge electrodes in combination with plate type collecting electrodes. The experimental validation shows good agreement for the case of the round discharge electrode. The model predicts the effect of wire diameter, plate length and gas flow temperature. For the rigid discharge electrode, of the same electrode thickness as the diameter of the round electrode, much lower corona onset voltage was observed.