Solid-liquid-liquid Wettability and its role on Targeted Emulsified Solvent Injection (TESI)

Canada possesses the third largest world reserves of crude oil, mostly in the forms of heavy oil or bitumen in the oil sands. However, 80% are too deep to be mined, requiring in-situ extraction methods. This work involved the design of a chemical enhanced oil recovery (EOR) approach, referred to as Targeted Emulsified Solvent Injection (TESI), that uses a surfactant-oil-water (SOW) system in the form of an emulsified solvent formulation at low surfactant concentration (~0.8%) to extract bitumen from oil sands. Different from previous approaches, TESI features an unstable emulsion delivered to the porous media where it is meant to break, dilute the bitumen, reducing its viscosity, and producing an ultralow interfacial tension (IFT). According to a known theory of capillary displacement, the ultralow IFT should facilitate bitumen removal via shear forces. A gap in this theory was addressed, concerning the effect of surfactants on wettability and its potential impact on bitumen recovery. To this end, existing Surface-Liquid-Air (SLA) wettability models were evaluated for their suitability to predict Solid-Liquid-Liquid (SLL) contact angles for a wide range of interfacial tensions (IFTs) of surfactant-free systems on various materials. The Neumann’s equation of state (EQS) was found to predict well wettability changes with IFT changes. This extended-EQS was then combined with the Hydrophilic-Lipophilic-Difference (HLD) + Net-Average Curvature (NAC) framework, used to predict IFT, to estimate changes in wettability around the phase inversion point (PIP) of SOW systems. It was found that at the PIP –where IFT is ultralow– the wettability is nearly neutral, and more importantly, is nearly independent of the solid’s hydrophilicity, explaining why wettability did not seem to affect TESI performance. The most influential factor on TESI performance was the delivery of solvent. Under optimal delivery conditions, bitumen recoveries of 60-80% can be achieved.Ph.D.2021-11-11 00:00:0

Experience on Implementing a Project for Educating Students on Runaway Reaction Dynamics

To build awareness in second-year chemical engineering undergraduate students on runaway reaction dynamics and associated safety concerns, and to help students better identify crossovers between two different courses, a combined team project between the Heat and Mass Transfer and Applied Differential Equations courses at the University of Toronto has been implemented. To evaluate the effectiveness of this combined project on students learning, a survey was conducted around four different perspectives: (A) Contribution to learning, (B) Motivation and awareness, (C) Project structure and support, and (D) Personal experience and skills development. The results of the survey demonstrated that the project was effective at bringing awareness about safety issues and the role of students as future professional engineers. It helped them better learn the concepts seen in both courses and develop their team skills. A critical analysis of these results helped to provide guidance for improvement in future years are discussed