Electrocoalescence of Water Droplets in Oil Emulsions: Effect of Electric Fields, Surfactants, and Chemical Demulsifiers

• Author / Creator

  Dwaik, Carol G

• Stabilization of water-in-oil droplets during bitumen extraction and refining process poses a major challenge in the oil sands industry. These crude oil emulsions are stabilized by rigid films at water droplet-oil interfaces. The salty water remaining in oil causes equipment corrosion, catalyst poisoning in upgrading, lower product quality and extra transportation capacity, all of which immensely increase operation costs.An effective and clean method used for water removal is the integration of electric fields with chemical demulsifiers. Past studies proved that coalescence of water droplets under external electric field is significantly enhanced through increasing electric field strength up to critical voltages in various setups. However, more in-depth experimental tests are needed to understand fundamental interactions using model emulsions (i.e., droplet-droplet, thin films, oil phases), and to link to industry applications. This research investigates the use of electric fields in chemical and physical variations to combat stable emulsions in bitumen extraction processes.To understand the various phenomena that occur in water-in-oil emulsions, a setup of water-water droplets in oil is tested using a high voltage-modified Thin Film Draining Apparatus (TFDA). The experiments are split into two main sections, one investigates the effect of electric field variables while the other considers the effect of chemical and physical variations of emulsion systems. To elaborate, electric field variables include the application method of electric fields, such as ramp speed and field strengths. The results show that faster ramp speed leads to shorter coalescence time, and high field strengths cause unwanted droplet stringing (i.e., further emulsification); it is therefore crucial to evaluate these variables. Alternatively, chemical and physical properties of the emulsion systems were investigated, including the effect of type and concentration of demulsifiers, droplet size, and droplet overlap on electrocoalescence of water droplets in oil emulsions.The results of these experiments allow us to establish correlations among electric field and physical/chemical properties to gain a fundamental understanding in enhancing coalescence and demulsification, thus leading to more efficient phase separation.Supplemental material related to this thesis is available athttps://era.library.ualberta.ca/collections/7p88ck40x

• Subjects / Keywords

  • Induction timer
  • Shape
  • Paraffinic oil
  • Overlap
  • Dipole
  • TFDA
  • W/O
  • Asphaltenes
  • Phase separation
  • Surfactants
  • Size
  • Thin film draining apparatus
  • Electric fields
  • Thin film
  • Coalescence
  • Electrocoalescence
  • Demulsification
  • Model emulsions
  • Interactions
  • Chemical demulsifiers
  • High voltage
  • Crude oil
  • Model oil
  • Water-in-oil
  • Droplet
  • Emulsions
  • Draining

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-a5my-3r02

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.