Extraction of Bitumen from Athabasca Oil Sand Slurry Using Supercritical Carbon Dioxide

Extraction of hydrocarbons from an Athabasca oil sand slurry were conducted using supercritical carbon dioxide (SC-CO2). The oil sand was slurried to a 1:1 ratio with water and experiments were conducted using a laboratory-scale batch supercritical fluid extraction (SFE) system. Preliminary tests revealed the importance of mixing rate on hydrocarbon yields. A 23 factorial experiment was then conducted to test the effect of temperature, pressure, and modifier (toluene) addition on hydrocarbon extraction yield. When toluene was absent, hydrocarbon extraction yields were greater at the high temperature (60°C); however, when toluene was present, the combination of low temperature (31°C) and high pressure (24.1MPa) provided greater extraction yields. The experiment that produced the highest cumulative hydrocarbon extraction yield was analyzed by GC-FID for product-quality. Two composite samples and one time series sample revealed a carbon distribution range of the extract centering on C25, corresponding to the light gas oil range as classified in petroleum fractions.