Membrane-based wet electrostatic precipitation

Wet electrostatic precipitators (ESPs) hold great promise for collecting acid aerosols and fine particulates, as well as virtually eliminating re-entrainment. However, disruptions due to spraying (misting) of water, formation of dry spots due to the effects of water surface tension (channeling), and corrosion of the collector surfaces may limit applicability of current wet precipitators. Novel corrosion resistant membrane collection surfaces developed at Ohio University could address these problems by promoting uniform water distribution via capillary flow. Such membranes were used to replace steel plates in a wet electrostatic precipitator. Capillary action between the strands in the membranes facilitates water-based transportation and cleaning, maintaining an even distribution of water over the fabric. Tests were performed to measure the collection efficiency of the membranes relative to steel plates, as well as to quantify key properties of the membranes. The results indicate that membranes can be completely cleaned via continuous low velocity, gravity-assisted capillary flow of water while maintaining the electric field. Particulate collection capability was measured to exceed that of metal collectors under the same conditions, as well as those predicted by the Deutsch-Anderson equation. (C) 2004 Elsevier B.V All rights reserved.