Maintaining the PM Removal Efficiency of a Two-Stage ESP With External Ion-Injection Discharge via a Water Film on the Collection Plate and Cleaning of the Ionizer

A two-stage electrostatic precipitator (ESP) with a reduced footprint, external ion-injection discharge, and water film on the collection plate was developed for long-term operation. For optimal particulate matter (PM) removal efficiency, the ionizer of the external ion injection system was fixed at a distance of 5 mm from the bias plate. Under these operating conditions, the 0.3-mu m PM (PM0.3) removal efficiency was reduced to approximately 70% due to low migration velocity. The application of an additional collection plate extended the residence time of the charged particles in the electric field, which resulted in a removal efficiency exceeding 95%. However, long-term operation (675 min) of the two-stage ESP with external ion-injected discharge resulted in spark generation due to contamination of the ionizer, and the PM2.5 and PM10 removal efficiencies decreased linearly from 80.4% to 62.2% and 87.7% to 68.2%, respectively. Changing the ionizer to a pin shape with electrical specifications similar to those of carbon fibers resulted in water film formation on the collection plate. The PM2.5 and PM10 removal efficiencies remained at their initial levels for 120 min. The two-stage ESP with external ion-injected discharge operating with a water film is likely suitable for long-term operation in an industrial setting.

Automated summary

A two-stage electrostatic precipitator with reduced footprint, external ion-injection discharge, and water film on the collection plate was developed for long-term industrial operation. The addition of an extra collection plate and modifying the ionizer shape improved the PM removal efficiency and extended the operating time.