asphaltenes

Three different macromolecular structures of poly(ethylene oxide-b-propylene oxide) copolymers, used in formulations of commercial demulsifiers for breaking water-in-crude oil emulsions, were investigated. The interfacial activity (), the lower interfacial tension (m), the critical micelle concentration (CMC), the interfacial concentration (Γ) and the molecular area (A) adsorbed at the interface of the surfactant solutions were evaluated. These results were correlated to surfactant performance in coalescing three different asphaltene model emulsions.

The formation of aggregates of a fraction of asphaltenes extracted from Brazilian crude oil was investigated by measuring the interfacial tension and kinematic viscosity of their solutions prepared in different solvents. The interfacial tension results indicate the existence of critical micelle concentration (CMC) levels of the asphaltenes in solvents with solubility parameters sufficiently different from those of the asphaltene tested. The kinematic viscosity measures revealed the formation of aggregates at concentrations above the CMC.

Petroleum could be seen as a system of asphaltenes dispersed in other petroleum components. The petroleum components excluding the asphaltenes are referred to in this paper as Petroleum Medium that Disperses the Asphaltenes – PMDA). This paper proposes a methodology to determine solubility parameter of the PMDA by identifying a model solvent which, when added to the petroleum, does not affect the asphaltenes phase behavior.