An environmentally friendlier method of separating oil from tar sands has been developed by a team of researchers at Penn State University. This method, which utilizes ionic liquids to separate the heavy viscous oil from sand, also is capable of cleaning oil spills from beaches and separating oil from drill cuttings.
also known as bituminous sands or oil sands, represent approximately two-thirds
of the world’s estimated oil reserves. Canada
is the world’s major producer of unconventional petroleum from sands, and the United States imports more than one million
barrels of oil per day from Canada,
about twice as much as from Saudi
Arabia. Much of this oil is produced from
the production of petroleum from tar sands causes environmental damage. Part of
the damage comes from the storage of contaminated wastewater from the
separation process in large open air ponds. Wastewater from the ponds can seep into
ground water, and pollute lakes and rivers. In addition, the requirement for
large amounts of water can deplete the supply of local fresh water resources.
The Penn State separation method uses very little
energy and water, and all solvents are recycled and reused.
Painter, professor of polymer science in the Department of Materials Science
and Engineering at Penn State, and his group have spent the past 18 months
developing a technique that uses ionic liquids (salt in a liquid state) to facilitate
separation. The separation takes place at room temperature without the
generation of waste process water. “Essentially, all of the bitumen is
recovered in a very clean form, without any contamination from the ionic
liquids,” Painter explains. Because the bitumen, solvents and sand/clay mixture
separate into three distinct phases, each can be removed separately and the
solvent can be reused.
also can be used to extract oil and tar from beach sand after oil spills, such
as the Exxon Valdez and Deepwater Horizon incidents. Unlike other methods of
cleanup, the Penn
State process completely
removes the hydrocarbons, and the cleaned sand can be returned to the beach
instead of being sent to landfills. In an experiment using sand polluted by the
BP oil spill, the team was able to separate hydrocarbons from the sand within
seconds. A small amount of water was used to clean the remaining ionic liquids
from the sand, but that water also was recoverable. “It was so clean you could
toss it back on the beach. Plus, the only extra energy you need is enough to
stir the mixture,” says Aron Lupinsky, a researcher in Painter’s group.
researchers work with a group of ionic liquids based on
1-alkyl-3-methylimidazolium cations, a positively charged material with high
chemical and thermal stability, a low degree of flammability, and almost
negligible vapor pressure, which makes recovering the ionic liquid relatively
simple. The team has built a functioning bench top model system, and is in the
process of reducing their discovery to practice for patenting.
A New Process Cleanly Extracts Oil and Tar from Sand
April 1, 2011