Electrostatic precipitator with Surface Dielectric Barrier Discharge ionizer

Abstract

The performance of a two-stage electrostatic precipitator (ESP) with an ionizer with Surface Dielectric Barrier Discharge (SDBD), where the ionizer both generates the free charges and forces the airflow via the electrohydrodynamic (EHD) effect, was experimentally studied. The Particle Image Velocimetry Method (PIV) measurements revealed the airflow patterns and showed that the total flow rate generated by the ionizer (with both flat edge and saw-like high-voltage electrodes) increases with the applied discharge voltage up to a maximum of 73 l/min for 24 kV. These measurements, supported by Computational Fluid Dynamics (CFD) simulations, suggested that changing the airflow pattern with a flow guide would improve the filtration efficiency. This has been experimentally confirmed using an optical particle analyzer, and we recorded a maximum total mass filtration efficiency of 98% for the ionizer with a flat electrode and a flow guide with 3 mm inlet gap. We found that the filtration efficiency increases with the applied voltage up to about 14 kV, then decreases with the voltage due to a reduction in the particle charging rate caused by the high flow velocity of the particles through the discharge region. We also determined that, taking into account both flow rate and filtration efficiency, the ESP works optimally with an applied voltage of 18 kV–20 kV, achieving a filtration efficiency of 77% and simultaneously a flow rate of 63 l/min for the ionizer with the saw-like electrode and respectively 89% and 28 l/min for the ionizer with the flat electrode.