Alberta’s oil sands deposit is the third largest reserve of fossil fuel in the world. The fuel exists in the deposit as heavy oil, or bitumen, that needs to be extracted from the sands/clays, cleaned and refined into petroleum products. Currently a warm-water extraction process is used by oil sands producers to extract the bitumen from shallow deposits.
This process is plagued by high freshwater use (4-5 bbl of fresh water per bbl of oil), high energy consumption, i.e., high GHG emission (88 kg CO2 per bbl of oil), and large tailings impoundment areas (>170 km² so far). All three problems are caused by the mobilization of the fine minerals (clays) in the oil sands by the caustic warm water, which combine with un-extracted residual bitumen to form a gel-structure that holds water indefinitely. Since the trapped water cannot be recycled, fresh cold water is required and heating the cold water to 50ºC causes high energy consumption and GHG production. In the meantime large tailings ponds are required to impound the tailings.
UAlberta has been working with Imperial Oil in the past 10 years to develop nonaqueous extraction (NAE) processes through the Institute for Oil Sands Innovation (IOSI). The NAE can operate at ambient temperature and generate dry stackable tailings, thus eliminate all the three problems above. Our vision of how the oil sands, as an energy source, fits in an energy system in the near future is as follows:
Our vision of how the oil sands, as an energy source, fits in an energy system in the near future involves the surface mining of oil sands followed by an extraction process by which bitumen in the oil sands is recovered by using an environmentally friendly organic solvent. This non-aqueous extraction process generates the bitumen product and gangue that contains mostly solids (clay and sand particles) and small amounts of residue bitumen and organic solvent. The organic solvent in the bitumen product will be removed and reused before the bitumen is further refined to meet the application requirements. Residue solvent in the gangue will also be recovered and reused before the gangue is deposited back to the mining sites.
Note that this vision applies to other heavy oil resources, and eliminates upgraders. Tremendous research and development is needed to achieve this vision. While the in-situ branch is addressed by another Theme, this Work Plan addresses the surface mining branch. With the base budget of $3.3M over 7 years, we will address the two challenges of NAE:
1) Solvent recovery from extraction gangue
2) Cleaning of the bitumen-solvent product to meet refinery feed specifications.
