Natural zeolite catalyzed cracking-assisted light hydrocarbon extraction of bitumen from Athabasca oilsands

The bitumen in the Canadian oilsands reserves, one of the largest petroleum resources in the world, has higher viscosity and higher concentrations of contaminant heteroatoms and heavy metals than those found in typical crude oil. Current extraction processes, predominantly hot water extraction methods, are extremely water-intensive and generate high volumes of waste that is challenging to treat prior to reuse or release. Natural minerals such as chabazite and clinoptilolite, when acidified, have the ability to catalyze the cracking of bitumen, lowering the viscosity while adsorbing a large fraction of the undesirable compounds. In this study, light hydrocarbons (pentane and hexane) are employed instead of water to extract natural zeolite-cracked bitumen fractions from the oilsand matrix. Boiling point analysis of the light hydrocarbon-extracted bitumen fractions demonstrates that catalytic cracking by clinoptilolite reduces the vacuum residual fraction generated from pentane- and hexane-extracted bitumen by 50% (from 25% to as low as 12%). The products are almost entirely extractable using light hydrocarbons, indicating that the asphaltene fraction has been cracked. Based on these results, one can envision a waterless self-extraction process in which natural zeolites break down bitumen into lighter, less viscous components, remove contaminants, and produce light hydrocarbons in situ. (C) 2008 Elsevier B.V. All rights reserved.