Corona discharging and particle collection of bipolar transverse plate ESP

Abstract To improve the fine particle collection efficiency, a bipolar transverse plate electrostatic precipitation (ESP) technology was developed. In this ESP, there are not only the negative wire electrodes and ground plate electrodes, but also the ground wire electrodes and the negative plate electrodes. It has aroused a special interest about the corona discharging effect of the ground wire electrodes. Therefore, the corona currents of the negative wire-ground plate, the ground wire-negative plate, as well as the bipolar wire-plate electrodes have been investigated experimentally. In the experiments, the RS barbed wire and the C-plate are used as the electrodes for the purpose of the industrial application. The experimental results have shown that, when the wire-plate spacing is 200 mm, the corona current of the wire in the smooth side of the ground C-plate is 15% higher than that of curved side, however the corona current of the ground wire is about 30% less than that of the negative wires regardless of the wire is located at different sides of the industrial plate electrode. Moreover, the corona current of bipolar wire-plate electrodes is 30% less than that of the traditional wire-plate electrodes, and an important phenomenon had been discovered from this experimental work that, for the bipolar wire-plate electrodes, whenever the front side of the C-plate faces to the gas flow or not, the V I characteristics curve keeps almost no change at given wire-plate spacing. Last, an experimental setup was established for comparison of collection efficiency. When the negative polarity is applied to the bipolar transverse plate ESP, the collection efficiency increases sharply from 69.1% to 99.1%. Since both electrical forces and inertial forces play important roles in the bipolar transverse plate ESP, the penetration of the bipolar transverse plate ESP is 0.9%, which is substantially less than the penetration of 4.2% of the conventional ESP. The advantage of bipolar transverse plate ESP unit has been proved by successful operation in sintering flue control in China.