Molecular‐thermodynamic framework for asphaltene‐oil equilibria

Abstract

Asphaltene precipitation is a perennial problem in producing and refining crude oils.To avoid precipitation, it is useful to know the solubility of asphaltenes in petroleum liquids as a function of temperature, pressure and liquid-phase composition

Molecular Thermodynamics of Adsorption using Discrete-Potential Systems

“…In the same spirit of the approach followed in References [36,37] to modelling asphaltenes, the SAFT-VR methodology has been used to describe the precipitation of asphaltenes in several Mexican crude oils [39]. A very good prediction of the precipitation envelopes has been obtained, and we are currently working on the extension of this theory to predict the behaviour of asphaltene-resin mixtures in porous media.…”

“…A SAFT primitive model for asphaltene precipitation was developed in References [36,37], that describes the thermodynamic properties of an asphaltene-resin system considered as a solution, within the McMillan-Mayer approach, that is, introducing the Potential of the Mean Force (PMF) as the effective potential to take into account in the theoretical description. The aggregation behaviour of asphaltenes in asphaltene-resin mixtures within different host media has been studied on the basis of this PMF approach, using Molecular Mechanics and Molecular Dynamics [38], and according to the obtained computer simulation results, an important feature observed in the PMF of aggregated systems is the presence of repulsive barriers.…”

Adsorption-desorption of n–C7 asphaltenes over micro- and nanoparticles of silica and its impact on wettability alteration

“…Changes in temperature may influence the asphaltene aggregate size in the solution, altering their spatial disposition over the adsorbent surface and decreasing the intermolecular forces between the adsorbent and the adsorbate Nassar, 2010;Nassar et al, 2015c). Also, as the temperature is increased, the liquid density decreased (Wu, Prausnitz, & Firoozabadi, 1998), and the power of the solvent to dissolve the asphaltenes decreased, directly affecting their molar volume, which tends to increase with temperature (Diallo, Cagin, Faulon, & Goddard, 2000).…”

Characterisation of Asphaltenes and Modelling of Flocculation – State of the Art

“…These results are in complete contradiction with those of the colloidal approach put forward by Leontaritis and Mansoori. Although this approach helps us to understand the effect of resins on asphaltene precipitation, it is complex and requires a large number of experimental data. Wu et al (1998) therefore propose another approach, which considers flocculation as a liquid-liquid equilibrium. Asphaltenes and resins are considered as pseudo pure components which can combine, whereas the other constituents of the fluid represent a continuous medium.…”