Oil sands, also known as “tar sands“ or “bituminous sands“, can be either loose sands or partially consolidated sandstone saturated with a highly viscous form of petroleum. Compared with conventional techniques, extraction of oil from tar sands is expensive and hence depends on oil prices and the availability of efficient and sustainable extraction techniques.
Oil extraction from oil sands requires a large amount of water for different processes. Hot water used to reduce the viscosity of the oil makes up the largest share. After oil/water separation, the water is sent to the tailings ponds and can be reused as “recycle water“ without any further treatment. River water is primarily used as boiler feed water, but it also finds use as cooling water in the summer. Due to their resistance to organic matter and oil residues, desalination behavior, and thermal stability, ceramic nanofiltration membranes (NF membranes) can contribute to the development of new and more efficient recycling processes, including partial heat recovery.
In a current project started in 2013 together with partners Shell Global Solutions International B.V., Shell Canada Ltd., and Andreas Junghans - Anlagenbau und Edelstahlbearbeitung GmbH & Co. KG, 19-channel elements with ceramic NF membranes are being tested in an oil field in Canada.
The goal of this project is to make the recycle water usable for other purposes besides the current one (boiler feed water). From an environmental point of view, use of recycle water instead of river water would be beneficial, but this is currently not possible due to the high residual bitumen and solids contents of the tailings. Ceramic NF membranes completely remove suspended solids and residual bitumen and at the same time reject most of the multivalent ions, thereby enabling a much higher yield in the subsequent reverse osmosis process.