A Novel Solid–Liquid Equilibrium Model for Describing the Adsorption of Associating Asphaltene Molecules onto Solid Surfaces Based on the “Chemical Theory”

Abstract

Asphaltenes exhibit an amphiphlic behavior and tend to form colloidal i-mers, because of their chemical structure. The formation of colloidal aggregates can generate formation damage for the precipitation and/or deposition of asphaltenes, because of the degree of self-association, altering the wettability of rock surface and significantly affect crude oil viscosity and specific gravity. This study aims at introducing a novel model for describing, at the macroscopic level, the adsorption equilibria of self-associating molecules such as asphaltenes in solution onto solid surfaces based on the "chemical theory". The model describes the adsorption isotherms temperature-dependent using three parameters, namely, maximum amount adsorbed, constant of i-mer reactions, and Henry's law constant. Furthermore, a temperature-independent model of five parameters, based on the modifications of the constants of reaction and Henry's law using an Arrhenius-type equation was proposed for estimating the thermodynamics parameters, such as ΔG ads °, ΔH ads °, and ΔS ads °of the adsorption process. This model improves the understanding of interactions asphaltene−asphaltene and asphaltene−solid surface on the adsorption−equilibrium process. The theoretical predictions of isotherms were validated successfully by determining the root mean-square errors (RSM%) between data obtained from published literature and values predicted for asphaltenes and surfaces with differing chemical natures. More than 40 experimental data taken from literature have been used for validating the solid−liquid equilibrium (SLE) model for describing the adsorption isotherm of asphaltenes from different origins on surfaces with different chemical nature, which shows the model robustness due to the complexity of the liquid phase adsorption for those complex molecules.

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

“…Type II isotherms have often been described in non-porous materials, which lead to the formation of a multilayer of adsorbate on the microsilica surface (Franco et al, 2013a;Franco et al, 2013b). As observed, in the range of the low concentrations for the adsorption isotherms, the slope is higher for nanosilica than for microsilica, indicating a higher adsorption affinity for the nanoparticle system (Montoya, Coral, Franco, Nassar, & Cortés, 2014).…”

Metal Oxide Nanoparticles Supported on Macro-Mesoporous Aluminosilicates for Catalytic Steam Gasification of Heavy Oil Fractions for On-Site Upgrading

“…In addition, a higher acidity in the active sites generates an improvement in the affinity between the adsorbate and the adsorbent, showing a reduction in the H parameter. For a better comprehension of the adsorption process, the experimental data was described by the SLE model [90]. The values of the obtained model parameters and their associated R 2 and Root Mean Square Error (RSME%) values are shown in Table 3.…”

“…The adsorption isotherms of heavy crude oil fractions onto macroparticulate materials are described by the Solid-Liquid Equilibrium (SLE) Model based on the association theory of Talu and Meunier [90,116]. The expression of the model is given by:…”

A Realistic Look at Nanostructured Material as an Innovative Approach for Enhanced Oil Recovery Process Upgrading

“…The SiO 2 A nanoparticles showed better adsorption capacity than others as the adsorption potential to capture n-C 7 asphaltenes is in the order of SiO 2 A > SiO 2 >A l 2 O 3 . The acidic silica exhibited better adsorptive capacity especially at low concentrations owing to increased surface acidity of the nanoparticles as n-C 7 asphaltenes adsorption increases concurrently with increase in surface acidity [70].…”

“…The SiO 2 A nanoparticles showed better adsorption capacity than others as the adsorption potential to capture n-C 7 asphaltenes is in the order of SiO 2 A > SiO 2 >A l 2 O 3 . The acidic silica exhibited better adsorptive capacity especially at low concentrations owing to increased surface acidity of the nanoparticles as n-C 7 asphaltenes adsorption increases concurrently with increase in surface acidity [70].Heavy oils are typically known for their high asphaltene content (> 5 wt.%), such asphaltenes [71,72] forms viscoelastic network of large size nanoaggregate clusters and promote formation damage as a result of self-association, and if sub-saturated oil reservoirs exist at pressures above the bubble point. The asphaltene becomes excluded from the oil matrix and then forms deposits on the reservoir rock.…”