Adsorption at Oil/Water Interface: Application in SAGD Operation

  • Author / Creator
    Maryam Razi
  • Interfacial activity of SAGD PW endogenous surfactants, humic acids (HAs), and their interaction dynamics with naphtha-diluted Alberta oil sand bitumen (AOSB) present in model SAGD produced water has been addressed in the first part of this PhD thesis. Dynamic interfacial tension σ(t) between oil and water phases has been studied using a pendant drop tensiometer in the first part of this PhD thesis and its correlation to the properties of SAGD PW has been further investigated. The effect of AOSB dilution ratios, pH of model SAGD PW and surfactant concentrations on the dynamic interfacial tension (IFT) of naphtha-diluted bitumen/water interface has been monitored. A theoretical model of surfactant adsorption at the interface of naphtha-diluted bitumen/model SAGD produced water has been applied to the experimental curves. In the next part of this PhD thesis, the oil/water (O/W) interface at nano-scale has been studied using a thin liquid film (TLF) set up. The interface of O/W has been monitored for different aqueous phases of surfactant solutions and ionic liquids. Later, a systematic study of TLF of n-dodecane as an intervening liquid phase in aqueous surfactant solution is performed using a 3D-printed modified Scheludko-cell (MSC). The effect of the ionic strength of the ionic liquid (IL) phase on the current–voltage characteristic curve of the system is monitored. It is found that TLF conductivity increases as the ionic strength of the IL phase increases. Moreover, the transient study of the TLF conductivity showed that the TLF conductivity increases over time until it reaches to a quasi-steady condition. We obtained an induced conductivity for the TLF formed for two cases of SDS as anionic surfactants and KCl as inorganic hydrophilic ions. We later developed a model for the adsorption of the ionic species at the perfect dielectric liquid (PDL)/IL interface in both cases of the anionic surfactants and inorganic hydrophilic ions. In order to rule out the charge leakage effect within oil phase in the observed increase in the TLF conductivity, the oil film conductivity without the presence of any aqueous phase is measured under the current experimental conditions. The electric field applied to the TLF is also quantified by simultaneously solving the non-linear Poisson-Boltzmann equation for IL phase and Laplace equation for the PDL phase. Either studies rule out the evidence of charge leakage within the oil phase under the current experimental conditions. The validity of the surfactants adsorption at O/W interface is also examined by utilizing the pendant drop tensiometric study of the oil phase in aqueous solution. The adsorption time-scale of surfactants present in IL phase at O/W interface using this method was comparable to the electrical conductivity measurement done by MSC. In the last part of this PhD thesis work, a theoretical model has been developed to study the O/W interface electric potential at different applied voltages to the TLF. We anticipate that the results of this study will bring about a better understanding of the interfacial film properties leading to the advancement of the design of the next generation SAGD W/O or O/W emulsion separation unit operations and the furtherance of the prediction of the coalescence mechanism in SAGD PW emulsions.

  • Subjects / Keywords
  • Graduation date
    Fall 2019
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
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