Effect of hydrodynamic behavior on electrostatic potential distribution in gas–solid fluidized bed

In a gas–solid fluidized bed with a newly-designed gas-inlet structure, with gas entering exclusively in the core or annulus zone separately, changes in the hydrodynamic behavior are observed and thus the electrostatic potential distribution is regulated and controlled. From experiments conducted, electropositive potential in the upper particle circulation zone is observed while the bottom part displays electronegative characteristics. Compared to that with a normal gas-inlet condition, the fluidized bed with specific core–annulus gas-inlet structure behaves differently. As the superficial gas velocity is increased, the positively charged zone, as well as the upper circulation zone, expands when the fluidizing gas just enters the core zone; on the contrary, the negatively charged zone expands with the superficial gas velocity when fluidizing gas just enters the annular zone. At lower superficial velocities, the absolute value of the electrostatic potential in the center is less than that at the wall, while the two potential values approach each other when the velocity becomes higher. Moreover, a preliminary mechanism discussion about the effect of the flow pattern on the electrostatic potential distribution has been put forward for understanding the hydrodynamics and the electrostatic field, which is verified with the experimental results.

Fluidizing gas was controlled to enter exclusively core zone or annulus zone for the first time.Changes of hydrodynamic behavior have been obtained and their effects on electrostatic distribution are studied systematically.Mechanism about effect of flow pattern on electrostatic distribution is proposed based on electrostatic measurements.Figure optionsDownload as PowerPoint slideHighlights
► By a new gas-inlet structure, changes for hydrodynamic behavior can be obtained.
► Gas was controlled to enter exclusively core zone or annulus zone for the first time.
► Effect of hydrodynamic behavior on electrostatic distribution is studied in FBR.
► Mechanism about effect of flow pattern on electrostatic distribution is proposed.
► The mechanism discussion is verified by our electrostatic potential results.