Modeling the Kinetics of Asphaltene Flocculation in a Toluene-Heptane Mixture for the Case of Sonicated Crude Oils

Ultrasonic wave technology has been much attended in industrial applications such as removing of asphaltene particles from near wellbore region. But its application to inhibition of asphaltene flocculation remains a topic of debate in the literature, especially in the best of our knowledge there is no universal kinetic model that could predict asphalten flocculation in Toluene-n-alkane mixtures. In this work a set of confocal microscopy experiments is performed to investigate the size distribution of asphaltene flocks of crude samples exposed to ultrasonic wave at different time intervals. The results revealed that the DLVO colloidal model cannot be valid for ultrasonic radiated crude oil samples due to reversibility of flocculation process. Looking for a predictive model for reversible flocculation, smoluchowski equation which is highly used for modeling the coagulation process of inorganic compounds is assumed to be an appropriate choice. This model is modified and applied for prediction of the flocculation of asphaltenes under the influence of ultrasonic wave. Fractal analysis of asphaltene particles shapes were also applied in modeling. The model presented here can predict both size distribution and average radius of flocks for different time intervals and is applicable to the whole flocculation process, rather than DLVO models.