(185f) Removal of Particulate Fines from Organic Solvents Using Water Droplets As Collector Particles

Owing to the pressing need for a reduction in the usage of fresh water in the Clark process of bitumen extraction from oil sands, the oil sands industry has focused its attention on the development of an alternative, solvent-based extraction method in recent years. A key challenge in this new process is the removal of particulate fines from bitumen-solvent mixture. Current methods for particulate removal, such as centrifugation and solvent evaporation, are energy-intensive, and carry potential emission hazards. Motivated by the need for energy efficient methods, our project aims to provide insight into the feasibility of the use of an aqueous phase for collecting and separating fines from the bitumen- solvent mixture by obtaining statistical data for particle - drop impingement process. In this work, a PDMS-based microfluidic aspiration device has been developed to carry out particle-drop impingement experiments. Simulations were performed to obtain a measure of particle interaction time with the drop surface. We observed in the experiments the efficiency of capture of particles by the water droplet increases with the impingement rate, a result that is in contradiction to hitherto particle capture efficiency literature.  The possibility of the influence of hydrodynamic processes, such as film drainage, and thermodynamically-driven processes such as hole - nucleation and contact line motion, will be discussed. We map out the relationship between particle capture efficiency and flow rate, viscosity ratio and radius of the collector droplets.  These results will provide guidelines for the optimal operating parameters to effect efficient particle removal.