Experimental and Theoretical Study on Supramolecular Ionic Liquid (IL)-Asphaltene Complex Interactions and Their Effects on the Flow Properties of Heavy Crude Oils

Effectiveness of inhibitors to prevent asphaltene aggregation: Insights from atomistic and molecular simulations

The technological landscape for industrial processes handling asphaltene is evolving at a rapid pace due to the increase in the extraction of heavy crude oil. The main underlying challenges in this regard are the flow assurance, the recovery of the spent solvent, and the sophisticated extractor setup required to develop the process to an industrial scale. The number of studies focused on the handling of the asphaltene at the atomic and molecular scales is growing enormously in order to identify new sustainable solvents for the effective extraction of asphaltene from heavy crude oil or oil-bearing sands. This Perspective focuses on the importance of density functional theory and molecular dynamics simulations to explore the broader range of asphaltene inhibitors, e.g., nanoparticles, ionic liquids, and deep eutectic solvents, to prevent asphaltene precipitation. We provide a concise overview of the major accomplishments, analyze the aspects that require attention, and highlight the path-breaking studies having a significant impact on the process of chemical enhanced oil recovery from heavy crude oil reservoirs primarily based on atomistic and molecular simulations.

Probing the Effect of Aliphatic Ionic Liquids on Asphaltene Aggregation Using Classical Molecular Dynamics Simulations

One of the major constituents of heavy oil is asphaltenes. They are responsible for numerous problems in petroleum downstream and upstream processes, such as catalyst deactivation in heavy oil processing and blocking pipes while transporting crude oil. Probing the efficiency of new nonhazardous solvents in separating asphaltenes from crude oil is key to avoid conventional volatile and hazardous solvents by replacing these conventional solvents with new ones. In this work, we have investigated the efficiency of ionic liquids to separate asphaltenes from organic solvents (such as toluene and hexane) using molecular dynamics simulations. Triethylammonium-dihydrogen-phosphate and triethylammonium acetate ionic liquids are considered in this work. Various structural and dynamical properties are calculated, such as radial distribution function, end-to-end distance, trajectory density contour, and diffusivity of asphaltene in the ionic liquid-organic solvent mixture. Our results explain the role of anions, i.e., dihydrogen-phosphate and acetate ions, in separating asphaltene from toluene and hexane. Our study provides an important revelation about the dominant role played by the IL anion in intermolecular interactions which depends on the type of solvent (i.e., toluene or hexane) in which the asphaltene is present. The anion induces enhanced aggregation in the asphaltene-hexane mixture compared to the asphaltene-toluene mixture. The molecular insights obtained within this study on the role played by ionic liquid anion in asphaltene separation are key for the preparation of new ionic liquids for asphaltene precipitation applications.