Simulation and computer modeling of asphaltene in different solvents on oil-water interfaces using a molecular dynamic methodology.

Molecular dynamics (MD) simulations were used to study the thermodynamic properties of asphalt binder components, namely asphaltene, and other solvents, such as pentane or toluene, before and after adding pentane or toluene. The two systems were compared by MD simulation under lots of molecules, temperature and pressure to predict their internal energy, structure, and density as a function of time or distance between molecules. Then the simulation results of the two systems were analyzed and compared to determine the influence of different solvents on asphaltene aggregation behavior. The results show that the asphaltenes with pentane or toluene in the two systems have different structure and dynamic characteristics and will produce different precipitation and aggregation characteristics. The aggregation behavior of asphaltene at water - oil interface with or without pentane or toluene was studied. The relationship between the molecular structure and the aggregation of asphaltene in different solvents was investigated.

New modeling method to simulate asphaltenes at oil sands process in water management.

The study of various structures, physicochemical structures and dynamic characteristics of oil-water interface asphaltenes is an important basis for the large-scale development and efficient clean utilization of oil sands. The molecular dynamics simulations method provides a possibility for revealing the physicochemical structure and dynamic characteristics of oil sands. The emphasis of this paper is to study the physic-chemical structure of tar sands asphaltenes and the changes of their kinetic properties by using molecular dynamics simulations. Molecular dynamics was used to simulate the physicochemical and dynamic characteristics of asphaltenes in water treatment of the oil sands. In this research, the structural and dynamic properties of asphaltenes, such as density distribution, correlation (radial distribution function), root-mean-square deviation (RMSD), and mean azimuth shift (MSD), diffusion coefficient, the radius of gyration, volume viscosity and free energy in water treatment were systematically discussed. The simulation results of asphaltene at the oil-water interface revealed that, in the oil-water interface, oil and water will affect the solubility of asphaltene. The asphaltene molecules have different mobility and the ability to break molecular association, indicating that the structure and dynamic properties of asphaltene in the oil-water interface and the water-water interface are different.