Effects of agglomerates on electrostatic behaviors in gas–solid fluidized beds

• As a sheet fell, V-shaped fluctuations of induced potential could be observed.
• The competition effect was the reason for these V-shaped fluctuations.
• Competition effects were between charges on particles and particle concentration.
• Small agglomerates might make a polarity reversal of measured potential.

This work for the first time shows that both falling polyethylene sheets and small agglomerates significantly affect the electrostatic behaviors in a fluidized bed. By cold model experiments, this work found that V-shaped fluctuations of induced electrostatic potentials were observed as a sheet fell to a certain position, and polarity reversals of induced electrostatic potentials were discovered as some small agglomerates were added and fluidized in the lower part of the bed. Further analysis found that the falling sheet could affect the particle concentration distribution in the bed as well as the surface charges of particles, and these two factors always had opposing effect on the induced electrostatic potential and thus caused V-shaped fluctuations to appear. The reason for the reversal of polarity as small agglomerates were added was the appearance of the positively charged agglomerates in the measuring sensitivity zone. This work opens up new possibilities for agglomerates detection.

Figure optionsDownload as PowerPoint slide