Aggregation of Crude Oil-Modified Fine Solids in Aqueous and Non-aqueous Media

  • Author / Creator
    Darius, Juan
  • At different stages during the extraction of bitumen from the Athabasca oil sands, the removal of unwanted fine solids  whether suspended in aqueous or non-aqueous liquids  continues to present serious challenges to the oil sands industry. These fine solids are unique in that their colloidal properties are altered through adsorption of various bituminous components onto their surfaces. It is imperative to understand how these adsorbed species affect the colloidal stability of the solids in different liquid media.

    We report here a systematic investigation on the aggregation of silica particles in both water and organic solvents. The silica particles are either untreated or adsorbed with various fractions of bitumen (a total of six sub-fractions, based on solubility in aliphatic solvents, as well as interfacial activities of the fractions). The organic solvents (in which the solids are suspended) are mixtures of toluene and n-heptane at different ratios. The colloidal stability of the solids is examined on both the macroscopic and microscopic scales. On the macroscopic level, “jar tests” are performed to monitor settling rates in relation to the corresponding Stokes velocities. In the case of non-aqueous suspensions, it is revealed that, in terms of the toluene-to-heptane ratio of the solvent, there are clear points of transition between slow and rapid settling. On the microscopic level, direct measurements of adhesion forces are made between pairs of micron-sized glass particles using the microcantilever technique. These force measurements are correlated with the jar test results, revealing the influences that various bituminous fractions have on the colloidal stability of the fine solids.

  • Subjects / Keywords
  • Graduation date
    Spring 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    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.