(192c) Impact of Dispersion Stability on Asphaltenes in Bulk and at Oil-Water Interfaces

Asphaltenes are polyaromatic molecules commonly found in crude oil. Molecular structure often results in complex aggregation that depends on solvent quality. Additionally, asphaltenes are surface-active substances that adsorb at water-oil and air water interface. Both of these properties lead to complexities in oil field processing, especially when multi-phase processes are involved. To characterize and understand the interfacial activity of asphaltenes at oil-water interfaces, the solubility of asphaltenes in different nonpolar solvents (oils) is characterized. The bulk stability of asphaltenes in a range of nonvolatile solvent mixtures is characterized as a function of aliphatic/aromatic ratio. A millifluidic, droplet-based technique is utilized and a region of time-stable behavior is found at the aromatic rich region of a mixture of solvents. The interfacial activity of stable dispersions of asphaltene at oil-water interfaces is characterized and both dynamic and static interfacial tension are measured. Asphaltenes are shown to be surface active and the impact of solvent quality on interfacial activity and interfacial transport are reported.