Development and evaluation of a triangular prism-multiple tubular wet electrostatic precipitator for capturing moxibustion oil fumes

Abstract

Moxibustion oil fumes (MOF) have caused serious indoor air pollution. To solve the high costs problem existing in the current air purification technology, a triangular prism-multiple tubular wet electrostatic precipitator (WESP) was developed. The discharge characteristics of the modified WESP and the factors affecting its fractional collection efficiency (FCE) were explored in detail, and the collection performance of the modified WESP was further characterized by laboratory-scale tests. The results showed that the flushing water not only effectively cleaned the collection electrodes but also enhanced the corona current. Although increasing the applied voltage and reducing the flue gas velocity can improve the FCE, it was necessary to ensure that the ozone concentration met the emission standards. Specifically, the FCE of the modified WESP reached 43.09 %-97.48 % when the applied voltage was 15.5 kV, the flue gas velocity was 0.9 m·s−1, and the water consumption was 7.93 L· min−1·m−2. Under the optimal operation parameters, the modified WESP had an extremely low pressure drop (23 Pa) and a high clean air delivery rate (43.38 m3·h−1). After 12-h of continuous operation, the FCE of the modified WESP decreased slightly, but the FCE can be effectively recovered by cleaning the discharge electrodes. In conclusion, the modified WESP had the potential to efficiently capture MOF at low cost. Furthermore, the characteristic of MOF particles charged by the combustion process also helped us understand the high FCE of the modified WESP for MOF. Moreover, a modified efficiency equation of the triangular prism-multiple tubular WESP was proposed, and the experimental data were in good agreement with theoretical values. In addition, the modified WESP can provide a viable technical pathway to control oily particles emission.