Filtration characteristics of fibrous filter following an electrostatic precipitator

This study presents the results of investigations of a hybrid electrostatic filtration system (HEFS), which combines an electrostatic precipitator (ESP) and a fibrous filter installed downstream of the ESP. The particles escaping from the ESP carry large amount of charge and this can increase the filtration efficiency of the fibrous filter. The filtration characteristics, including the efficiency, pressure drop and ozone generation, were investigated experimentally. The influence of system parameters, including the filter type, applied voltage, and distance between the ESP and fibrous filter on the overall efficiency were also studied. The measured results show that utilizing the non-high-efficient fibrous filter to remove the charged particle could provide a much higher efficiency without adding the pressure drop due to the electrostatic force. If the efficiency was similar, the ozone generated by HEFS was much lower than that of the single ESP. The results proved that filter efficiency increased with a higher applied voltage and higher initial mechanical filtration efficiency. The distance between the filter and ESP had no influence on the system filtration efficiency. The efficiency of filter in HEFS supplied with the positive voltage was slightly lower than for the negative voltage. In addition, the mathematical model was utilized to model the air filter efficiency in HEFS. The modeled and measured results agreed reasonably. Overall conclusion is that the HEFS could operate at a high efficiency with the lower applied voltage, ozone generation and pressure drop.