The wet flue gas from the wet FGD tower enters the wet electrostatic precipitator (WESP) , and tens of thousands of volts of DC high voltage are applied between the anode tube and the cathode line of WESP, the air in the corona layer undergoes avalanche ionization, which produces a large amount of negative ions and a small amount of cations. The dust (fog) particles in the wet flue gas in the anode cylinder collide with the positive and negative ions produced by the discharge and become charged, the charged dust (fog) particles move towards the cathode and anode respectively because of the Coulomb force of the high-voltage electrostatic field, and release their charge after reaching the two poles, the dust (fog) particles are collected by the cathode and anode and are separated from the gas by gravity flowing downward; some of the dust (fog) particles themselves adhere to the anode plate (cylinder) and the cathode line due to their inherent viscosity, remove by Flushing.