11th East Asia Joint Symposium on Plasma and Electrostatic Technologies for Environmental Application (EAPETEA-11)

Achieving efficient particle charging while minimizing particle deposition is a key challenge in the design of front-end chargers for two-stage electrostatic precipitators. To address the excessive particle deposition associated with the continuous grounded plates of conventional wire–plate chargers, a segmented ground-plate charger with inter-plate gaps was developed to reduce particle losses while maintaining a high charging performance. The effects of discharge mode, discharge voltage, pulse frequency, gas velocity, and particle concentration on the charging performance were systematically investigated and compared with those of a conventional continuous-plate charger. Bipolar pulsed electrostatic agglomeration and subsequent two-stage electrostatic precipitation experiments were further conducted to evaluate the practical performance of the proposed charger.
Under an inlet particle concentration of 30 mg/m³, an average gas velocity of 2.5 m/s, a peak voltage of −21.2 kV, and a pulse frequency of 1 kHz, particles with a diameter of 1.3 μm achieved an average charge of approximately −700 elementary charges per particle. The particle loss fraction remained below 50% throughout the PM₁ size range and did not exceed 25% for particles smaller than 0.33 μm. Bipolar pulsed electrostatic agglomeration increased the geometric mean particle diameter by up to approximately 5%. Subsequent two-stage electrostatic precipitation tests demonstrated that bipolar pulsed agglomeration effectively enhanced particle collection, achieving a number-based collection efficiency of approximately 80% for particles in the 0.2–0.5 μm range and approximately 95% for particles around 1 μm. These results demonstrate that the segmented ground-plate configuration can effectively suppress particle deposition during charging while maintaining a high particle charge level, providing a promising structural strategy for developing low-loss, high-performance chargers for two-stage electrostatic precipitation.
 

Electrostatic precipitation ; bipolar electrostatic agglomeration ; microsecond pulse ; two-stage ESP.