Characteristics of an electrostatic precipitator for submicron particles using non-metallic electrodes and collection plates

Abstract

We have developed a novel ESP that uses an anticorrosive carbon brush precharger and plastic collection plates into which metallic films are inserted. The collection efficiency of the ESP was measured using ultrafine KCl particles by varying the applied voltages, the number of channels in the charger, the gap between the collection plates, and the air flow rates. Tests of loading and cleaning on the collection plates were also conducted using JIS class # 8 dusts and KCl particles. The experimental results showed that the precharger (400×400×800 mm 3) generated a lot of unipolar ions whilst producing negligible concentrations of ozone (<5 ppb), and that when the ESP was operated with 16 channels of ionizers and a 10 mm gap between the collection plates (400×400×185 mm 3), it removed more than 95% of the ultrafine particles with a power consumption of only 5 W and a pressure drop of 5 Pa per 1200 m 3/h at 2 m/s. It was also shown that by increasing the applied voltage and the number of channels in the charger, and by decreasing the gap between the collection plates, an improvement in the collection efficiency of the ESP could be achieved for a scale-up. It was also found that the collection efficiency for the ultrafine particles fell from approximately 95% to 50% after dust loading with 100 mg/m 3 of the JIS dusts for 2 h, but then recovered perfectly to the efficiency of the initial state after the collection plates were sprayed with water at 25 L/min for 4 min.