The Role of Napthenic Acids and Asphaltenes on the Phase Behavior of Bitumen-water Systems

In this thesis, the behavior of naphthenic acids and asphaltenes in bitumen-water systems is explored. The bifunctional model was developed to characterize polar oils in surfactant-oil-water systems. This model incorporated the HLD equation and the Langmuir adsorption isotherm to determine the interfacial adsorption of surface-active compounds. For the first time, the amphiphilic behavior of naphthenic acids was characterized by an EACN and a Cc, simultaneously. Furthermore, it was concluded that in the presence of a surfactant, asphaltene molecules are rejected from the interface of the bicontinuous phase due to their large size, and thus have little effect on the curvature of the system. Consequently, the bifunctional model predicted the phase behavior of bitumen-water systems from naphthenic acids’ surfactant-like and oil-like behavior at different pH values. This resulted in the prediction of the phase inversion point, at which the properties of the system reach minimum interfacial tensions and emulsion stability.M.A.S.2021-11-19 00:00:0