Electric charge neutralization by addition of fines to a fluidized bed composed of coarse dielectric particles

Effects of external electric field on bubble and charged particle hydrodynamics in a gas–solid fluidized bed

“…It was revealed in the previous works that in some gas-solid systems, all of the particles carried charges of the same sign (unipolar charging), while in others, some particles were positively charged, and others were negatively charged (heteropolar charging) [6][7][8]. In the latter cases, particles tended to agglomerate and complicated the hydrodynamics [9].…”

Electrostatic charging during the flow of grains from a cylinder

“…The ability of one material to coat either equipment surfaces [7,34] or other particles [34,35] can lead to unexpected charging behavior, for example some materials, even when added in very small concentrations, substantially decrease the net charge produced during powder handling and prevent agglomeration [13,35,36]. In gas-particle flows it has been shown that the addition of fine particles can reduce the accumulation of electrostatic charge.…”

Electrostatic charging phenomenon in gas–liquid–solid flow systems

“…Jean et al (1992) reported that adding up to 15% of fine polyethylene powders to a Group B polyethylene bed improved the gas-solid fluidization quality (i.e., higher bed expansion). Wolny and Opalinski (1983) reported that for the drying of polystyrene beads, the effect of fine additives was independent of the electric nature of the added fines. Active coal powder (conductor), titanium dioxide powder (semiconductor), and powder of pigment A-extra (dielectric), which are general ad- ditives in many polymer processes, were used as added fine materials in the experiments of Wolny and Opalinski (1983).…”

“…According to Wolny and Opalinski (1983), fine Geldart's group C particles act as spacers and increase the contact area of the particles in gas-solid systems. As a result, the dissipation rate of electrostatic charges in a fluidized bed is expected to increase.…”