Interfacial properties of crude oil asphaltenes mixed with ethoxylated surfactants and medium chain alcohols

Abstract

Asphaltenes represent a crude oil fraction constituted by complex macromolecules and comprise the largest portion of interfacial active compounds of the petroleum. Asphaltenes have been subject to the research on colloidal aspect because their implications mainly on the formation and stabilization of foams and emulsions, inversion of wetting behavior and deposition and solid adhesion on surfaces. This work aims to evaluate the interfacial properties of crude oil asphaltenes in oil/water systems containing ethoxylate surfactants and medium-chain alcohols. The research motivation is mainly the notable results obtained from studies carried out by the author of this project in which medium-chain alcohols displayed a strong influence on the oil-in-water emulsion properties and formulation. Data from that studies identified anomalous phenomena during the rheometric flow of oil-in-water emulsions which were identified as phase segregation and wall slip. Wall slip was attributed to the formation of a low viscosity layer, ascribed as oil-depleted layer. The occurrence of oil-depleted layer implies on the pumping energy saving and, consequently, on the economic benefit to the oil industry. The experimental methodology proposes the asphaltene extraction and characterization and the determination of the interfacial properties of films containing asphaltenes by means interfacial tension and surface potential measurements. (AU)