Removal of Mist Particles by a Two-Stage Electrostatic Precipitator Featuring Plastic Plate Electrodes

Abstract

To reduce corrosion, cost, and weight, we developed a nonmetallic, two-stage electrostatic precipitator (ESP) using electrodes fabricated from carbon ink and polyethylene terephthalate (a plastic), rather than expensive corrosion-resistant metals. Five collection modules were manufactured; we varied the materials used to fabricate the high-voltage and ground electrodes. The plate-type electrodes of the collection module were made of stainless steel, carbon-coated plastic (CPC), or plastic-coated carbon (PCP). Particle removal performance was investigated by the voltages of the precharger and collection modules, the particle diameter, the airflow rate, and the particle collection area. The particles were an oil mist. The electrode material had little effect on particle removal performance. The experimental performances of two-stage ESPs featuring plastic and carbon plate electrodes met the theoretical efficiencies predicted by the Deutsch equation and Cochet charging theory. Although fluttering developed when the flow velocity exceeded 2 m/s over CPC electrodes, the use of PCP electrodes (the rigidity of which was reinforced by the plastic coatings) eliminated fluttering. Moreover, in an extremely humid condition where the water vapor continuously condensed into water droplets, the polyethylene terephthalate film of the PCP electrode ensured stable operation without spark regardless of humidity or water droplets on the surface. In summary, plastic electrodes were light and economical, while affording high removal efficiencies similar to the removal efficiencies of metals. Moreover, the PCP electrode plastic coating protected the carbon ink from abrasion and corrosion.