Preliminary Study of the Effect of Pressure on Asphaltene Disassociation by Molecular Dynamics

Abstract

Abstract Preliminary studies of the effect of pressure on a system composed of 32 asphaltene molecules immersed in a solvent (pentane or toluene) were carried out. In this case, this system was randomly distributed into a cubic box of 49430.9 Å3 of volume. The NPT simulations showed spontaneous asphaltene disassociation when an asphaltene aggregate was immersed in toluene as a function of the pressure. Among the main configurations found, offset π-stacked geometry was the most frequently observed stacking form. Calculation of the radial distribution function on the system also revealed that the nearest asphaltene molecules have an average separation distance around 3.8 Å. This is a value in agreement with the classical model for asphaltene aggregates developed almost 40 years ago. Some possible asphaltene micelle formation and phase transitions will be described.