Collection efficiency of ultrafine particles by an electrostaticprecipitator under DC and pulse operating modes

摘要

High particle collection efficiency in terms of particle weightvolume mg/m3 is well achieved by a conventional electrostaticprecipitator (ESP). However, the collection efficiencies in terms ofnumber density for the ultrafine (particle size between 0.01 to 0.1μm) or submicron particles by a conventional ESP are still relativelylow. Therefore, it is necessary to improve the collection efficiency forultrafine particles. In this work, attempts have been made to improvethe ultrafine particle collection efficiency using the short pulseenergizations. The present version of ESP consists of three sets of wireplate type electrodes. For ESP under DC operation modes, experimentalresults show that the collection efficiency for DC applied voltagedecreases with increasing dust loading when particle density is largerthan 2.5×1010 part/m3. For ESP under pulseoperating modes, the particle collection efficiency increases withincreasing pulse peak voltage until 25 kV then decreases with increasingpulse peak voltage. The ultrafine particle collection efficiency basedon particle density by DC energizations is much higher compared withpulse energizations without DC bias may be due to the reentrainments ofultrafine particles