Industrial & Engineering Chemistry Research, Vol.43, No.22, 7103-7112, 2004
Selective rejection of inorganic fine solids, heavy metals, and sulfur from heavy oils/bitumen using alkane solvents
Bitumen and heavy oil + alkane solvents exhibit complex phase behaviors. For example, organic components of these materials can be solubilized and inorganic solids dispersed into a highpressure gas phase. Conversely, they can also be partitioned into as many as three bulk phases: a gas phase, a liquid phase that is largely free of inorganic solids, and a phase comprising essentially all of the inorganic solids and a small fraction of the organic material. The outcome depends on the temperature, pressure, and solvent-to-feed ratio. Mass balance results for a screening survey for Athabasca vacuum bottoms (ABVB) + alkane solvents (pentane, heptane, decane, and dodecane) are reported along with a limited number of phase composition data for ABVB + pentane and dodecane mixtures. Reversible phase behavior and irreversible thermolysis conditions were considered. The key findings are that inorganic solids are readily partitioned from ABVB irrespective of the solvent and operating conditions employed, while key heavy metals, such as vanadium, require a combination of phase behavior and mild thermolysis. Sulfur- and nitrogen-containing species possess low rejection selectivities in this solvent series.