Pulse Energization System of Electrostatic Precipitator for Retrofitting Application

A cassette type pulser module has been developed for electrostatic precipitators for upgrading the performance of existing plants. The module is inserted between the existing dc power supply and corona electrodes. Its pulse-forming capacitor is charged up to the voltage much higher than the dc power supply voltage, using a voltage-doubling circuit. The stored charge is directly delivered through a rotating spark gap to the corona electrodes without using coupling means like a pulse transformer or a coupling condenser. Saw-teeth voltage appears on the corona electrodes at a switching frequency, including at its leading edge a transient LC oscillation with a very sharp first peak and a fast decaying amplitude. This acts as the submicrosecond pulse energization producing very active negative streamers uniformly distributed along the entire length of corona wires of the conventional construction. The average of the saw-teeth voltage produces a dc field between the corona and the collecting elctrodes. This “direct-coupled pulse energization” indicated in our laboratory test exactly the same collection performance as the hitherto most effective submicrosecond pulse energization using a coupling capacitor and a dc bias voltage. A specific feature of the present pulse energization system is its simplicity in construction and low initial and operating costs.