Electrostatic precipitator as a generator rather than a remover of small droplets

The electrostatic precipitator (ESP) is used all over the world to clean pa rticles from contaminated industrial and domestical air. Recent observation s and experiments however a re disturbing. These indicate that, when captur ing an oil mist or possibly droplets in general, phenomena occur that can c ause the ESP to generate rather than remove (sub)micron particles. At spots where the electric field strength is high enough, collected droplets defor m into a conical shape, the so-called Taylor cone. At the tip of this cone a jet is formed that breaks up in an enormous number of (sub)micron-sized d roplets. In the ESP, this occurs at the charging corona wires and at sharp points on the collector plates. Because a part of the ESP energy is thus be ing used to spray droplets electrically, less energy can be utilized for io nization to charge incoming particles. Simultaneously, the active field str ength between the collector plates decreases. These factors result in a sub stantial decrease in collection efficiency over the total size range. In ad dition to this overall decrease in efficiency, particles in the order of 1 mu m are generated from the tip of the developed Taylor cones. Most of thes e generated droplets will be trapped in the ESP, but droplets formed close to the exit of the plates, depending on the configuration of the ESP, will be discharged from the precipitator. Thus, for particles of this size, the ESP is a particle generator rather than a particle remover.