Electrostatic discharge in powder-storage silos: Frequency and energy analysis under various conditions

Abstract

To explore the electrostatic discharge behavior of charged powders in industrial silos, discharge experiments are conducted based on a full-size industrial silo discharge platform. Electrostatic discharge mode, frequency, and energy are investigated for powders of different polarities. Although the powders have low charge-to-mass ratios (+0.087 μC/kg for the positively charged powders and -0.26 μC/kg for the negatively charged ones), electrostatic discharges occur approximately every 10 s, with the maximum discharge energy being 800 mJ. Powder polarity considerably influences discharge energy. The positive powders exhibit higher discharge energy than the negative ones, although discharge frequency remains similar for both. Effects of powder charge, humidity, and mass flow on discharge frequency and discharge energy are quantitatively analyzed, providing important insights for the improvement of safety in industrial powder handling.