Collection efficiency of electret bag filter for charged fine particulate matter
In this study,the bag filters were charged by single needle corona discharge with negative DC power supply,and a hybrid electrostatic filter comprised of pre-charger and electret bag filter were designed and manufactured.The collection efficiency of electret bag filter for uncharged,positively charged,negatively charged and bipolarly charged particles(0.3～10μm)were systematically studied,and the stability of collection efficiency for particles with different charge types were compared under different flow velocity conditions.Compared to raw bag filter for capturing neutral particles,the collection efficiency of electret bag filter for charged particles was higher.Especially for the particles with a size of 0.3pn,the collection efficiency increased from 79.9％to 99.9％(positive charge),99.3％(negative charge)and 98.6％(bipolar charge),respectively.The electrostatic collection efficiency compensates for the reduction of mechanical collection efficiency with the increase of flow velocity.For the 0.3pm particles,the decrement of collection efficiency decreased from 9.4％(neutral)to 0.06％(positive charge),0.2％(negative charge)and 5.2％(bipolar charge),respectively.More specifically,the enhancement of collection efficiency by coulomb attraction was stronger than that by coulomb repulsion,and both were superior to the agglomeration behavior.Three filter cake models were inferred by SEM to systematically explain this experimental phenomenon.These findings are very important for further studying the combination of electrostatic and mechanical collection mechanism of bag filter for fine particulate matter.
electret bag filterfine particulate matterchargingcollection eficiencyfilter cake
万方数据
维普
