Mathematical Description of Ionic Surfactant-Oil-Brine Systems
Creators: name: Saboorian Jooybari, Hadi
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: Microemulsions
subject: Micelles
subject: The DLVO theory
subject: Colloidal interactions
subject: Electrical double layer
subject: Surface charging
subject: Engineering
subject: Engineering--Petroleum
subject: Engineering--Chemical

description: Over the past decades, microemulsions have become increasingly attractive for application in diverse areas of science and engineering. Microemulsion systems exhibit unusually complex phase behavior that makes the prediction of their performance and properties very difficult, if not impossible. Despite the development of advanced characterization techniques, the high cost and time requirements have severely restricted their large-scale practical applications. This fact emphasizes the irreplaceable role of predictive phase behavior models for saving time, energy as well as money. This dissertation is intended to fill existing research gaps and solve industrial challenges by developing new mathematical models for predicting the behavior and structural parameters in ionic surfactant-induced microemulsions. Since surfactants, as the main component of such systems, act at the oil-water interface, a few phases of this thesis focus on studying and modeling an electrical double layer (EDL) and surface charging processes to be able to approach the problem from different points of view. First, a systematic critical review of the available computational methods concerning microemulsions is performed with the main goal of guiding researchers through the maze of identifying research gaps, industrial challenges, and future directions by comparing them in different aspects including the underlying physics, assumptions, simplicity, advantages, limitations, drawbacks, accuracy, applicability, and generality to provide an outlook of constraints and opportunities for future development. The second phase is directed at development of theoretical physics-based formulas for accurate quantification of EDL thickness in symmetrical electrolyte solutions for different particle shapes. In the third phase, accurate approximate analytical solutions are derived for the calculation of electric potential distribution within an interstitial EDL in various particle geometries. Then, accurate physics-based surface charging models are developed for quantification of curvature-dependence of surface potential, surface charge density, and total surface charge for the general case of cylindrical and spherical charged particles immersed in a symmetrical electrolyte solution with implications in oil-in-water microemulsions. Next, analytical models are developed for prediction of surface charging parameters of electrolyte-trapping nonelectrolyte-immersed charged cylindrical and spherical particles with implications in water-in-oil microemulsion systems. After that, the proposed surface charging models are used to quantify adsorption of ionic surfactant molecules onto the surface of normal micelles in aqueous media. The results of this phase allow academic researchers and industrial practitioners to calculate the size of micelles formed in aqueous solutions by ionic surfactants using a few simple parameters whose exact or estimated values are readily available. Finally, the proposed surface charging models are combined with material balance equations, the DLVO theory, and an equilibrium condition to predict the complex behavior, structural parameters, and geometrical features in ionic surfactant-induced microemulsion systems. The models developed and fundamental understanding gained in this dissertation find far-ranging applications in many areas of science and engineering in addition to chemical and petroleum engineering.