Numerical Investigation of the Capture of Polydisperse Particles by Charged Droplets

Abstract

The capture of particles by charged droplets was simulated by considering the electrostatic interactions of droplet-droplet and droplet-particle. The results indicate that the electrostatic repulsion between droplets leads to a dynamic accumulation mode of particles. However, the droplet spacing has an insignificant effect on the capture efficiency when the electrostatic deposition predominates. The increase of droplet charge remarkably improves the capture efficiency, in which the capture of fine particles accounts for the largest proportion. Compared to the droplet charge, the droplet size shows a limited improvement in the capture efficiency. Reducing the droplet velocity prolongs the capture time instead of enhancing the capture capacity per unit time, thereby improving capture efficiency.

Experimental Study on Particle Removal of a Wet Electrostatic Precipitator with Atomization of Charged Water Drops

“…The advantage of atomization of charged water drops in the WESP could be mainly attributed to the small diameter, high density of charged droplets, and large relative velocity between droplets and particulates resulting from electrodynamic breakup of water drops . The large relative velocity could enhance the inertial intercept in micron particles, and the high density of droplets is beneficial for improving the collision probability by thermal motion in submicron particles, which promoted the particle charging and agglomeration in the electric field and overall improved the particle removal performance with a large reduction of water consumption.…”

“…As a result, together with the decrease in droplet size under evaporation, this contributed to an increase in the droplet charge-to-mass ratio . Notably, it is the contact charging that dominated the droplets’ charging process because the droplet charged via corona charging in the electric field could only obtain charges no more than 1/10 of the Rayleigh limit. , …”