Self-Assembly of Asphaltene Aggregates: Synchrotron, Simulation and Chemical Modeling Techniques Applied to Problems in the Structure and Reactivity of Asphaltenes

Abstract

Increased understanding of the structure and chemistry of asphaltenes is essential to developing ways of mitigating the effects of asphaltenes, destroying them or finding new uses for them. The chemical structure and physical structure of the asphaltenes are unique and much has been learned about their physics and chemistry.1 However, there are still fundamental questions regarding the origin and structure of asphaltenes that remain to be answered. In this report, new synchrotron WAXS (wide angle x-ray scattering data) and SAXS (small angle x-ray scattering data) for Venezuelan and Mexican asphaltenes are reported showing the ubiquitous presence of the “asphaltene particles” with sizes in the 3–5 nm ranges. The particles exist both as correlated packets in the precipitated asphaltene and in the parent crude oil as individual particles. Furthermore, in the second section of this report the self-assembly of the “asphaltene” particles from model compounds is reported. That the “asphaltene particles” can self-assemble indicates the basic stability of the particles and generates interesting questions regarding the origins of petroleum. Increasingly, heavy crudes are becoming a major source of petroleum hydrocarbons as lighter crudes become scarce. One major difference between a light crude and a heavy crude is the asphaltene content of the crude. The asphaltene fractions contain most of the metals in the crude and generally more sulfur and