Electrostatic Precipitation of Carbon Soot from Diesel Engine Exhaust

A moving belt-type electrostatic precipitator (MBEP) has been developed for the control of diesel engine particulates. It indicates 95-percent collection performance for soot with 1-¿m mass- median diameter (MMD) when used in combination with a pre- agglomeration system consisting of a precharger and a parallel-plane collector. The insulators supporting the discharge electrode were located outside the precipitator so that they were not subjected to soot contamination. The very fluffy conductive soot collected on the moving belt was brought to the rollers where it was pressed and scraped off. The soot deposition on the discharge electrode could be corrected by using a fishbonelike multineedle discharge electrode. Very active coronas from its sharp needle points produced a remarkable self-cleaning effect by corona-induced oxidation of the soot.