Extraction of hydrocarbons from Athabasca oil sand slurry using supercritical carbon dioxide

The oil sands industry is seeking innovative technologies to address the water intensity and the high-energy consumption associated with current oil sands processing technologies. This research therefore investigates the use of supercritical fluid extraction (SFE) as an alternative to the current water-based extraction technology, Bitumen, a complex mixture of hydrocarbons, was extracted from an Athabasca oil sand slurry using supercritical carbon dioxide (SC-CO2). Preliminary experiments revealed the importance of a higher mixing speed and a longer static time on hydrocarbon yields. In a second set of experiments, when toluene was introduced as a modifier, a higher SC-CO2 density (i.e. high pressure, low temperature) led to higher extraction yields. In the absence of toluene, higher temperature conditions (i.e. lower SC-CO2 density) provided higher extraction yields suggesting desorption resistant hydrocarbon components in the oil sand matrix slurry are released as a result of increasing temperature. Using gas chromatography-flame ionization detector (GC-FID), the experiment that produced the highest cumulative hydrocarbon extraction yield was analyzed for product quality and the extracted hydrocarbons were observed to center on C-25. (C) 2015 Elsevier B.V. All rights reserved.