LAUSR

The impact of mixing conditions on the removal of water and solids from high-water, poor-quality bitumen froth was explored. Naphtha diluent and a demulsifier were added to improve removal of water and solids from bitumen froth. The mixing and subsequent settling of this system were carried out in the confined-impeller stirred tank (CIST), a lab-scale mixing test vessel with well-characterized, relatively-uniform mixing conditions. A protocol for finding the proper demulsifier dosage at which to study mixing effects was applied successfully. High mixing energy J and the pre-dilution of demulsifier (characterized by its injection concentration IC) improved dewatering and solids removal performance, agreeing with earlier studies in diluted bitumen and bitumen froth of higher quality (Laplante et al, 2015, Arora, 2016). An unexpected finding was that dewatering was significantly delayed in poor-quality froth: it was not detectable until up to 45 minutes in some cases. This induction time was replicated and w...