(72a) Investigation of the Impact of Inorganic Solids on Asphaltenes Precipitation

The presence of inorganic solids in Athabasca bitumen was recently reported to significantly increase the rate of asphaltene precipitation in diluted bitumen. The previous research indicated that asphaltenes precipitate on the surface of inorganic solids following a heterogeneous precipitation mechanism. In order to better understand the role of inorganic solids on the solubility and kinetic precipitation of asphaltenes, it is important to study under which conditions the heterogeneous or homogeneous mechanism dominates the precipitation process. In this talk we will explore the impact of inorganic solid and diluent type on the mechanism of asphaltene precipitation. To accomplish this task, inorganic solids were removed from a diluted bitumen, and different kinds of the inorganic solids were added back to study the impact of solid type and concentration on the precipitation kinetics of asphaltenes. The mass of precipitated asphaltenes was measured as a function of time. Moreover, by changing the solid:asphaltene ratio, the influences of homogeneous aggregation and heterogeneous nucleation can be determined. Furthermore, scanning electron microscopy (SEM) with focused ion beam (FIB) milling was used to characterize the precipitated asphaltenes in the presence of inorganic solids to provide visual evidence of the precipitation mechanism. Overall, this study can establish an improved understanding of the influence of inorganic solids on the precipitation kinetics and mechanism of asphaltenes precipitation.