The influence of asphaltene-resin molecular interactions on the colloidal stability of crude oil

Abstract

g r a p h i c a l a b s t r a c t Micellar structure of asphaltene in a dispersing medium of lighter resins, aromatics, and saturates. a b s t r a c tIn the colloidal hypothesis of vacuum residua and asphalt, micelles are assumed to have an asphaltenic core with the greatest weight and aromaticity and an outer shell composed of lighter and less aromatic molecules. The true nature of the micelles, and the asphaltenic core in particular, has always been a debatable issue among asphalt researchers. One of the frequently asked questions is whether asphaltenes exist as stacked layers within the micelles or as single molecular units stabilized by resin molecules. In this paper, we investigate the correlation between the number of asphaltene sheets and the final stability of the system in a medium of asphaltene and resin components. Our evaluation is based on rigorous quantum mechanical calculations using a DFT-D approach. Our quantitative findings corroborate the view that the colloidal behavior of crude oil is better described by asphaltene-asphaltene associations. Moreover, our calculations show that if both asphaltene and resin are present, resin-asphaltene interactions are preferred over asphaltene-asphaltene interactions only if the number of resin molecules per micelle is greater than the number of asphaltene molecules per micelle.

Mechanism of asphaltene aggregation induced by supercritical CO2: insights from molecular dynamics simulation

“…This is in agreement with the results obtained by recent quantum mechanical calculations. 57 A shoulder occurs at about 0.9 nm for the PMF curve under vacuum, corresponding to the offset structure of the asphaltene dimer. 20 The PMF reaches a steady value in scCO 2 as the separation between them is about 0.6 nm.…”

Modeling of surfactant adsorption on coated quartz crystal surfaces during surfactant flooding process

“…showed that resin-asphaltene interactions are prominent only if the number of resin molecules is greater than the number of asphaltene molecules [36]. The empirical ratio Resins (wt%)−0.4×Asphaltenes (wt%) ν involves and demonstrates the above-mentioned effects of resin and asphaltene on surfactant adsorption coefficients.…”

Influence of Asphaltenes in the Properties of Liquid–Liquid Interface between Water and Linear Saturated Hydrocarbons

“…In actual fact, consolidated asphaltene films around the droplets of emulsion do not coalesce after certain aging times. Obviously, adsorption kinetics and MD studies play a key role in the mechanical properties of films and an asphaltene adsorption with diffusion controlled at short times with individual molecules, transitioning possibly to a barrier-controlled regime in which larger aggregates are involved, 14 all of which helps in understanding the interfacial phenomena system assisting in the area development.…”