Electrostatic Attraction of Particles: The Implications of Field Theory on Coalescer Design

Abstract

A body of literature exists describing macro scale investigations with electrostatic coalescers based on DC, pulsed DC, and AC fields when applied to crude de-watering, de-salting, etc. Unfortunately, the push to very compact coalescers raises a requirement for detailed understanding of the fundamental physics of micro scale particle-particle attractions. Experience with frequency-controlled coalescer systems indicates a frequency dependency in the coalescence behaviour. (In-house data indicates a potential for increasing droplet growths by factors as high as four when comparing line frequency experiments to optimal frequency experiments.) The literature indicates that this variability may in-turn be related to particle (and coating) transport behaviour as well as electrophoretic separation of film macromolecules. The purpose of this work is to present the results of work aimed at reviewing and interpreting locally acquired data with respect to coalescence behaviour of real and model crude oils acquired using laboratory coalescer models.