Discharge characteristic of barbed electrodes in electrostatic precipitator

Electrostatic precipitator (ESP) is the mainstream technology for controlling emissions of coal-fired thermal power units in China. The barbed electrode (RS or BS) is paired with the electrostatic precipitators. However, such electrodes have serious internal suppression effects and easily cause the current density in some areas to be zero, affecting the electric field distribution. To explore this characteristic, the current density distribution on the surface of the collecting plate was tested on the electrostatic precipitator experimental device, and the suppression effect of the BS barbed electrode and the existence of the “current blind zone” were obtained. The mathematical model of corona discharge was then established to numerically solve the V-I characteristics of the BS barbed electrode's inner and outer discharge tips and quantify the suppression effect between the discharge tips. Finally, to improve the suppression effect and the current density distribution, the BS barbed electrode's structural parameters optimization schemes and supporting circular tubes in the single electrode-plate ESP model were proposed. The results show that the spurs' optimized structure can effectively improve the corona discharge capacity and weaken the suppression effect. At the same time, it was found that when the supporting component is a round tube or flat plate, the shielding effect will be produced. The addition of auxiliary needles on the supporting round tube cannot improve the current density distribution. Additional needles on the supporting plate can eliminate the phenomenon that the current density is zero. The shielding effect of the supporting tube is further explained. The research results provide a theoretical and experimental basis for the optimal design of barbed electrode and ESP's electrode configuration.