Investigating Multi-Needle Electrode Configurations for Improved Corona Discharge Charging of Nonwoven Filter Media

Abstract

Filter media are essential components in air purification systems across various industries, including HVAC, chemical, pharmaceutical, and biotechnology sectors. With the rise in environmental fine and ultrafine particles, conventional filters face limitations in long-term filtration efficiency. This study introduces a novel multi-needle electrode designed to enhance the electrostatic charging of filter media via corona discharge. We experimentally assessed the electrode's performance by measuring the charge deposited on nonwoven polypropylene filter media and examined how key parameters—the applied voltage, the distance between the multi-needle and planar electrodes, the charging duration, and the number of needles—influence the charging process. The results demonstrate that increasing the needle count enhances corona discharge intensity, leading to higher charge accumulation on the filter media. Optimal charging was achieved at specific voltage levels and charging duration; however, exceeding these optimal conditions resulted in charge saturation and inversion due to the crossover phenomenon. The findings highlight the importance of precise control over charging parameters to optimize filtration efficiency. This innovative electrode design offers a promising solution to improve air purification systems, contributing to environmental sustainability by reducing energy consumption, waste generation, and aiding compliance with stringent environmental regulations.