Dynamic Interfacial Tensions and Dilatational Viscoelastic Properties of Asphaltenes at Oil/Water Interface at High Pressure and High Temperature Conditions

• Author / Creator

  Luo, Meng

• The dynamic interfacial tension and dilatational viscoelasticity behaviors of asphaltenes at oil/water interfaces were investigated by means of an oscillating droplet tensiometer. This oscillating droplet tensiometer was modified to handle temperature of 120 °C and pressure up to 700 kPa. For dynamic interfacial tension, the effect of temperature, addition of artificial surfactants and aromaticity of solvent were investigated. It was found that increasing temperature, addition of surfactant and decreasing the aromaticity of the solvent could decrease the dynamic interfacial tension and accelerated the diffusion rate of asphaltenes migrating to the oil/water interface. It was also found that the adsorption kinetics of asphaltenes at oil/water interface can be categorized into three regimes where the Regime I is the fast diffusion-controlled process and Regime III is the slow adsorption-controlled process with the Regime II being the transitional stage in between. For interfacial dilatational behavior, the effect of temperature for pure toluene/water system, temperature with asphaltenes at toluene/water system, concentration of asphaltenes and salinity of aqueous solution were investigated. It was found that increasing temperature of pure toluene/water or asphaltenes in toluene/water system can reduce the elastic modulus significantly at different oscillating frequencies from 0.1 to 1 Hz. In addition, concentrated asphaltene solutions at oil/water phase have shown reduced elastic moduli and decreasing significantly if the frequency increased. Finally, as the salinity of aqueous solution increased, the elastic moduli increased as the interface became more rigid. These phenomena reveal the general trend in emulsion treating and oil recovery in various industrial processes.

• Subjects / Keywords

  • interfacial tension
  • dilatational viscoelastic properties
  • asphaltenes
  • interface
  • high pressure
  • high temperature

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-tb5m-6w15

• 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.