AFFINITY OF ASPHALTENE MODELS OF VENEZUELAN CRUDE OILS TO WATER/OIL INTERFACES. A MOLECULAR DYNAMICS STUDY

Abstract:

In Venezuela, Acevedo et al. proposed asphaltene models (A1 and A2 fractions) for crude oil with the aim of explaining the difference in found experimental solubility in n-heptane and toluene. However, its behavior and preference for certain interfacial regions was not studied. In the present work, we studied the preferential affinity of these asphaltene models by water/n-heptane and water/toluene interfaces using molecular dynamics simulations to 300 K. Systems were constructed considering the model of bilayers. GROMOS53A6 and SPC force fields were used to describe asphaltene, toluene, n-heptane and water molecules, respectively. All calculations were performed within the GROMACS-5.0. 2. In function of density profiles, we found that A1 and A2 fractions has affinity for the water/n-heptane interface and forms aggregates in the toluene bulk of the water/toluene system. Moreover, interfacial properties and types of molecular aggregations were evaluated.

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