LAUSR

Asphaltenes are precipitated solids found in crude oils that are composed of aromatic hydrocarbons and small amounts of non-volatile species (S,K, Ca, P, V, Ni, Zn, ....) which when they form accumulate as deleterious deposits in piping used to transport and/or store oil. Their presence adversely affects viscosity, and interfacial properties of oils and their evolution from individual molecular species into aggregates and finally into very large deposits is a challenge to fully characterize. Their formation is a dynamic process involving both morphological and chemical changes as a function of temperature, pressure and initial crude oil composition. The molecular and colloidal structure of asphaltenes have been the subject of numerous studies, and various models have been proposed [1]. The Yen-Mullins model, proposes that there are three stages: firstly small ~ 1 nm molecular particles; followed by nanoaggregates and finally massive clusters which range from hundreds of nanometers to macroscopic dimensions [2,3].