Critical comparison of electrostatic effects on hydrodynamics and heat transfer in a bubbling fluidized bed with a central jet

Abstract

In many industrial process, electrostatic charges are inevitable. and affect the hydrodynamic behavior and heat transfer ability of chemical equipment. A comprehensive study of the electrostatic effect on bubble behavior, particle fluctuation velocity and heat transfer coefficient in the fluidized bed with a central jet has been evaluated in this paper by Eulerian-Eulerian two fluid model coupled with electrostatic model and energy model. The simulated voidage profiles at different positions, bubble detachment time and initial bubble diameter are compared with experiment results from the literature. The bubble behaviors including bubble frequency and bubble numbers, combined with particle fluctuation parameters are analyzed in both charged and uncharged system. Electrostatic effect on two kinds of heat transfer coefficients are quantitatively compared, namely bubble to emulsion phase heat transfers based on the gas throughflow velocity and gas solid local heat transfer. Simulation results show that electrostatic charges decrease bubble numbers and granular temperature, whereas the averaged heat transfer coefficients are enhanced. Overall, the electrostatic effect on the hydrodynamic and heat transfer characteristics can be revealed.

Electrostatic Distribution in the Riser of the Multizone Circulating Fluidized Bed for Polypropylene

“…Partial experimental results of Dong et al were in accordance with simulated results of Hassani et al . Besides the hydrodynamics in the dense-phase bed layer, electrostatics also plays an important role in the process of particle elutriation, and even affects heat transfer ability. − …”