Related Experiment Video
Updated: May 12, 2026
08:03
Advanced Self-Healing Asphalt Reinforced by Graphene Structures: An Atomistic Insight
Published on: May 31, 2022
Effect of asphaltene structure on association and aggregation using molecular dynamics.
Mohammad Sedghi1, Lamia Goual, William Welch
1Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States.
The Journal of Physical Chemistry. B
|April 16, 2013
Summary
Molecular dynamics simulations reveal that aromatic core interactions drive asphaltene association. The number of aromatic rings and heteroatom positions significantly influence association free energy, impacting aggregation behavior in solvents like toluene and heptane.
Area of Science:
- Petroleum Geochemistry
- Materials Science
- Computational Chemistry
Background:
- Asphaltene aggregation significantly impacts petroleum industry processes.
- Limited experimental data exists on asphaltene association free energy and aggregation size.
- Current thermodynamic models inadequately represent asphaltene association.
Purpose of the Study:
- To investigate the relationship between Gibbs free energy of asphaltene association and molecular structure.
- To compute association free energy and aggregation numbers using molecular dynamics (MD).
- To understand the role of molecular structure and solvent effects on asphaltene aggregation.
Main Methods:
- Molecular dynamics (MD) simulations using GROMACS.
- Umbrella sampling technique to compute potential of mean force.
- Simulations of 36 asphaltene molecules in toluene and heptane.
Main Results:
- Aromatic core interactions are the primary drivers of asphaltene association.
- Association free energy increases with the number of aromatic rings.
- Heteroatoms on aromatic cores have a greater impact than those on aliphatic chains.
- Aliphatic chain length affects aggregation size but not dimerization.
- MD simulations predict three aggregation stages: nanoaggregation, clustering, and flocculation.
- Asphaltene association free energy is higher in heptane than in toluene.
Conclusions:
- Molecular structure, particularly aromaticity and heteroatom placement, dictates asphaltene association free energy.
- Steric repulsion from aliphatic chains influences aggregation size.
- MD simulations provide a mechanistic understanding of asphaltene aggregation and precipitation.
- Solvent properties significantly affect asphaltene association and aggregation behavior.
