Mesoscale modeling to study isolated asphaltene agglomerates

Abstract

The mesoscopic behavior of asphaltene plays a significant role in the formation of microstructures and agglomerates. In this study, a new coarse-grained model is developed to investigate the formation of aggregated microstructures in asphaltene. Disk-like building block is adopted as the basic unit in the coarse-grained model. The forcefield parameters based on Gay-Berne potential are derived from the full atomistic simulations and applied in the coarse-grained simulations. The results show that randomly orientated asphaltene disks gradually adjust their positions and orientations during equilibrium process, and reach the jammed state with different columnar structures containing packed asphaltene disks. The packing fraction and the microstructures of agglomerates are affected by the aspect ratio of asphaltene disks, temperature and pressure. The developed coarse-grained model can characterize the evolution of asphaltene microstructures and help understand the formation mechanism of asphaltene agglomerates. The in-depth analysis reveals the influencing factors on asphaltene agglomerates, which can enlighten the solutions to aggregation problems of asphaltene system.