Experimental Investigation of Electrostatic Reduction in a Gas–Solid Fluidized Bed by an in Situ Corona Charge Eliminator

Abstract

Accumulation of excess charges on insulated particles due to triboelectric charging can cause various powder industrial hazards. This work developed a novel in situ corona charge eliminator (ICCE) to neutralize the electrostatic charge in a gas–solid fluidized bed. In order to verify the feasibility of this method, variation of the electrostatic voltage, charge-to-mass ratio, and electric field before and after the application of ICCE was systemically investigated. The results showed that, under gas velocities of less than 2 U/Umf, particles were less charged, and the negative corona discharge caused a polarity reversal. As the gas velocity was increased, particles were more charged, and the charges on the particles were only partially neutralized by an identical corona discharge. Further analyses indicate that the charge neutralization efficiency was significantly influenced by both the triboelectric- and corona-charging processes. The superficial gas velocity was found to have a strong influence on the above two charging processes, and the charge neutralization efficiency favored a larger gas velocity. Besides, the equilibrium charge of the particles after the application of ICCE strongly depended on the initial charge accumulation in the fluidized bed.