A Regular Solution Based Model for Evaluating Asphaltene Stability of Upgraded Heavy Oils
Most of the heavy oil and bitumen produced in Western Canada is transported through pipelines to refineries in North America. Prior to transportation, the high viscosity of those fluids must be reduced by either dilution with a light solvent or upgrading. The high costs associated with handling diluents has increased the interest in upgrading; that is, the thermal conversion of high viscosity heavy oil or bitumen into a less viscous product. Upgraded heavy oils and bitumen require less solvent prior to pipeline transportation and have a higher market value compared to diluted heavy oil or bitumen. However, the changes in chemical composition of the fluid during upgrading can trigger the precipitation of heavy components which can then deposit on surfaces and cause fouling.
The aim of this study is to develop and test a Regular Solution based approach to model the precipitation of heavy components from upgraded fluids. An existing model will be modified as necessary based on a comprehensive database collected from a pilot plant. The proposed approach will be a valuable tool in the simulation and scaling of the BituMax partial upgrading process being developed by NEXEN Energy ULC.