A Method for Direct Measurement of Electrostatic Charge Generated By Particle-Wall Friction in Gas-Solid Fluidized Beds

Electrostatic charges generated by continuous friction between particles and between particles and the reactor wall in gas-solid fluidized beds can cause problems such as unstable operation and reduced productivity and product quality. Various measurement studies have been conducted to identify factors that affect electrostatic charge generation in fluidized beds. However, research on direct measurement methods for electrostatic charge generation on the metal surface of the reactor is lacking. In this study, we proposed a electrostatic charge measurement technique near the metal surface of the reactor wall.

Experiments were conducted in a cold flow model of a gas-solid fluidized bed reactor (50.8mm-i.d. x 600mm-high) with polyethylene particles that generated significant electrostatic charges. An inner sensing electrode (50.8mm-i.d. x 20mm-high) made of SUS material that does not interfere with gas-solid flow was installed to measure electrostatic charges under various fluidization conditions.

As the gas velocity and fluidization time increased, the amount of electrostatic charge accumulation within the particles increased due to increased particle-particle contact and particle-wall friction. The electrostatic charge by the developed probe showed opposite polarity results compared to the external measurement method commonly used in literature and demonstrated high sensitivity reflecting the direct behavior of the particles.