Oilsands researchers look to decaffeinated coffee

Coffee process could be used to reduce water usagein the oilsands

Manipulating microbes and methane, or employing a process similar to
that used to decaffeinate coffee beans in order to reduce water usage
in the oilsands, may seem like strange science.

 

But a
recent presentation by two University of Alberta researchers working
on projects that may reduce the need for fresh water-and perhaps even
eliminate the need for tailings ponds altogether-showed new approaches
that could help ease the strain on an already-taxed Athabasca River.

 

Julia
Foght and Selma Guigard offered their research as possible alternatives
to a gathering of 50 at the School of Energy and the Environment's
first "SEE the Research at Work" seminar.

 

Foght highlighted
her team's research with bio-densification, a process that studies how
methane-producing microbes seem to accelerate the settling effect
within tailings ponds. The naturally occurring process allows for
quicker settling of the solid tailings waste and the accelerated
recovery of water, which can be used to reduce the need for fresh water
in other processing operations.

 

"We're trying to find out the mechanism, how it works," said Foght. "Once you know that, you can start to manipulate it."

The
added benefit to this process could be the production of methane,
although trapping it could pose a challenge. Researchers would have to
find a way to capture the gas produced by the stimulated microbes, or
to find another way to stimulate them, to remove the gas.

There
is also the task of identifying which of the millions of microbes
present in the tailings are performing the work, then determining how
best to stimulate them.

"We do know some of the microbes
involved [in the process]," said Foght. "So we do have a sort of a
scheme of how things could work, based on how a sewage treatment plant
works. They are very much analogous."

So far, lab tests have
produced impressive results, and the researchers are hoping to be into
large-scale field trials within the next three years. That will give
Selma Guigard the opportunity to carry on with her research into what
could be the next logical step in eliminating or significantly reducing
water usage.

Guigard, who is also working with Foght on her
project, is looking to apply a process called supercritical fluid
extraction in order to remove the need for tailings ponds in the
pursuit of bitumen extraction. That extraction process is also used to
remove caffeine from coffee beans by bathing them in a pressurized
carbon dioxide environment and filtering the gas to remove the caffeine.

Having
seen the process used to remove heavy contaminants from soils, she
believes that a similar application can be used to remove the bitumen
from the oilsands.

Guigard's research is still in its infancy,
but she and a partner from the University of Guelph are working on
models that would show the feasibility of the use of a waterless
extraction project using carbon dioxide and solvents or compounds in
place of water.

"Carbon dioxide is one of the most commonly
fluids for supercritical fluid extraction. We have been conducting our
current research with carbon dioxide but we will be testing additional
solvents as well," said Guigard. "Other studies have used it, as well
as other supercritical solvents, and have shown that some of these
solvents had better absolute yields than pure supercritical carbon
dioxide in terms of bitumen extraction."

There are some
drawbacks to the usage of this process, Guigard notes. Production
costs, the availability of solvents and the ability to cleanly separate
solvents from the bitumen may be challenges. However, she notes that
the research has drawn interest from other countries with largely
untapped oilsands deposits.

Guigard is cautiously optimistic
about when there will be concrete results to research, and is using
this time to convince those who may not see the possibilities.

"We
would like to build a pilot-scale plant here at the University of
Alberta," she said, which, if successful, could provide the impetus for
building a larger-scale project site in Fort McMurray..

"Good
results from the university pilot would take about three to five years,
and a field-scale pilot may need another few years after that."

 
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