Corona Discharge Characteristics in Electrostatic Precipitator Under High Temperature

Harmful substances, such as particulate matter (PM), nitrogen oxides, and sulfur compounds in exhaust gas emitted from marine diesel engines have a great impact on the air environment. Among them, especially black carbon in PM has a negative effect on global warming. The exhaust gas from marine diesel engines using fuels containing heavy fuel oil has a high PM concentration and high temperature. Therefore, a commonly used diesel particulate filter is not suitable for collection because it tends to cause clogging and reduce efficiency. Furthermore, it is often the case that ships are at sea for more than one month, so it is difficult to replace the filter, that is, maintenance is difficult. On the other hand, an electrostatic precipitator (ESP) has the advantages of a simpler structure, lower pressure loss, and higher collection efficiency of high concentration particles. This suggests that the ESP is suitable for collecting harmful substances from the marine diesel exhaust gas. At high temperatures, corona discharge is unstable, and a flashover tends to occur at low applied voltage. Therefore, it is necessary to study the stable corona discharge generation range for the stable operation of the ESP. The purpose of this research is to analyze the optimal electrode structure and its corona discharge characteristics under the simulated exhaust gas of a diesel engine in the range of 100 °C – 400 °C using a negative dc power supply.