A more eco-friendly method for extracting oil and tar from sand has been developed by a group of researchers at Penn State University. Using ionic liquids to separate heavy viscous oil from sand, the team’s technique could help reduce toxic waste from surface-minded oil sands and aid clean-up efforts after oil spills.
Tar sands, also know as bituminous sands or oil sands, constitute approximately two-thirds of the world’s estimated oil reserves. Canada is the world’s major producer of the unconventional petroleum from tar sands, and the US imports more than one million barrels of oil per day from Canada, nearly twice as much as from Saudi Arabia. An estimated 32 billion barrels of oil could potentially exist in Utah’s tar sands.
Extraction and separation of these deposits are often expensive and harmful to the environment because they contain complex mixtures of sand, clay, water and bitumen, a “heavy” or highly viscous oil.
Processing this mixture to fuel requires significant amounts of water and energy and generates contaminated waste water that is stored in open air ponds. Toxic to aquatic life, this waste water can seep into groundwater.
However, the new method uses very little energy and water, and all solvents are recycled and reused. Paul Painter, professor of polymer science at Penn State and his team developed this new method using ionic liquids (salt in a liquid state) to facilitate the separation. No waste process water is generated since the separation takes place at room temperature.
The bitumen, solvents and sand/clay mixtures separate into three distinct parts. They can be removed separately and solvents can be reused.
This method can also be used to extract oil from beach sand after oil spills. Using sand polluted by the BP oil spill in one experiment, the team was able to separate hydrocarbons from the sand within seconds. After a small amount of water was used to clean remaining ionic liquids, the sand was so clean it could be returned to the beach, instead of landfills.
The team works with a group of ionic liquids with high chemical and thermal stability, low flammability, and negligible vapor pressure, making recovering the ionic liquid relatively simple.
The team has built a bench-top model system and is currently reducing their discovery to practice for patenting.
Source: Nic Halverson, Discovery News