Study on Electrostatic Precipitator for Diesel Exhaust Gas - Composition and Electrical Resistivity of Marine Diesel Exhaust Particulates

Abstract

One of the technologies to reduce PM emissions is an electrostatic precipitator. Electrical resistivity of the target particles is an important parameter in determining the performance of an electrostatic precipitator. If the resistivity of particles captured on the collection wall is low, re-scattering of the collected particles will occur. On the other hand, reverse ionization or the back-corona phenomenon occurs in the case of high resistivity, eventually resulting in sparkover. The resistivity of PM emitted from marine diesel engines is not fully understood. In this study, the authors developed a new instrument to measure particle resistivity, and used it to calculate the apparent electrical resistivity of PM exhausted from marine diesel engines. The results found that the apparent resistivity of PM exhausted from two-stroke engines was higher than that of PM from four-stroke engines. This is due to the high ratio of SOF contained in PM from two stroke engines. Therefore, when the ESP system is utilized to treat exhaust gas from two-stroke diesel engines, it is necessary to pay considerable attention to reverse ionization or the back-corona phenomenon.