Design and Application of Responsive Composite Particles for Multiphase Separations of Bitumen Emulsions in Bituminous (Oil) Sands Extraction

  • Author / Creator
    Liang, Chen
  • The development of more environmentally-friendly and cost-effective extraction and production technologies is a key to sustaining heavy oil and bitumen production. The high viscosity of the heavily degraded petroleum requires additional processing in order to recover such challenging resources from both shallow surface deposits and deeper underground deposits. Intensive processing conditions require substantially more energy while the degraded nature of the heavy crude and bitumen leads to a lower price. The extraction involves numerous processes that separate valuable hydrocarbons from water and solids. Complete separation of heavy oil (bitumen) is not typically possible, due to the complexity of the bituminous (oil) sand ore. As a result, multiphase waste streams are generated at each step, which require a special treatment and/or complex disposal protocols. The dispersed nature of the waste makes its management difficult and expensive. Preparing specially designed composite particles by combining the properties of different materials may provide an effective method for such challenging tasks, by taking advantage of desirable and supressing undesirable properties. Responsive behaviour can be incorporated into the composite particle to prepare smart materials tailored to the specific applications. To this end, various types of responsive particles were prepared and tested in this thesis research, including: 1. Particles with Switchable Wettability. Particles with switchable wettability were prepared from silica by chemical functionalization of its surface with CO2-switchable amidine moieties. The surface of switchable particles, under CO2, is more hydrophilic due to the ionized surface groups while, in the absence of CO2, it is less hydrophilic as surface group revert back to their basic non-ionic state. Both switchable oil-in-water and water-in-oil emulsions were thus stabilized/destabilized using solid particles with switchable and tunable wettability. 2. Responsive Absorbent Particles. Changes to the surface properties of particles can induce changes to colloidal stability. Composite absorbent particles consisting of an absorbent core coated by an interfacially active material were prepared by emulsion droplet dehydration of specially formulated emulsions. The composite absorbent particles with initial intermediate wettability were effectively dispersed in non-aqueous environment such as oil-continuous emulsions (e.g., bitumen emulsions) and attached to emulsified water droplets. The surface of the composite absorbent particles became more hydrophilic and formed large aggregates following absorption of water. Large aggregates of spent absorbent particles were much easier to separate. 3. Interfacially active Magnetic Particles. Interfacially active particles were prepared by sequential adsorption of different cellulosic materials onto magnetic iron oxide (Fe3O4) particles. Interfacially active magnetic particles were effectively attached to the oil-water interface and imparted magnetic susceptibility to the biphasic mixture. Adding such interfacially active magnetic particles to biphasic waste (e.g., emulsion droplets, rag layers and sludge) allowed biphasic waste to be magnetically separated. The ability to induce a response in the properties or function (e.g., emulsion or colloidal stability) of a particle can result in smarter processes that are specifically designed to take advantages of changing process conditions. Alternatively, manipulation and separation of responsive (i.e., magnetic) particles can be facilitated by applying an external force (i.e., a magnetic field). By matching a process with an appropriate responsive particle, it is possible to design processes with reduced operating cost, less waste, and fewer environmental and health risks. Specifically, different responsive composite particles were designed and prepared to dewater bitumen emulsions by absorption and enable magnetic separation of emulsions droplets, rag layer and sludge.

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  • Degree
    Doctor of Philosophy
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.