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What's New:
Article Archive List
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Fish passage project wins ACEC Grand Award (April 2008)
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Project wins awards for innovation and improved efficiency (2007)
•
Hibbing Office Relocates (October
2007)
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Minnesota Pollution Control Agency Commissioner Brad Moore
Spoke at Barr (June
2007)
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Coal Drying at Power Plant Improves Boiler Efficiency, Reduces
Air Emissions (June
2007)
Coal Drying at Power Plant Improves Boiler Efficiency, Reduces
Air Emissions
A project funded in part by the Department
of Energy promises to increase energy efficiency at coal-burning
power plants
One challenge associated with operating
a coal-based power plant is the varying amount of heat that
can be recovered from the coal, which depends on its type
and quality. For many years, coal-based plant operators trying
to improve efficiency have had to seek out higher quality
coal from suppliers. Based on early results of a project underway
at Great River Energy's Coal Creek Station in Underwood, North
Dakota, they may soon have another option.
Recent work by Great River Energy (GRE)
and Barr, in conjunction with the Industrial Commission of
North Dakota, the Electric Power Research Institute, Lehigh
University, and Falkirk Mining Company, has shown that drying
lignite coal before it is burned can significantly increase
its net heat (Btu) value and therefore its efficiency. Because
drying the coal takes energy, previous thinking was that the
effort would have no net benefit. But in pilot tests using
waste-heat streams from the Coal Creek power plant, the coal's
moisture content has been reduced by 25 percent—with
no additional energy required.
Same energy, less
coal, cleaner air
When moisture is removed, the net Btu value is increased and
less coal is needed to generate the same amount of energy—resulting
in fuel savings and an estimated increase in efficiency at
Coal Creek Station of about 5 percent. Dryer coal means less
moisture goes into to the boiler, which means less flue gas
is emitted. And that's easier on the environment, reducing
sulfur dioxide emissions by 25 percent and nitrogen oxide
and mercury emissions by 7 percent.
With such promising initial results, construction
of a prototype dryer for additional testing is under way.
Once that testing is complete, additional dryers will be constructed
and tested on one of Coal Creek's two 546-megawatt units.
A patent is pending on the dryer technology, with the hope
that it can be marketed globally for use at other coal-fired
power plants.
This project is one of eight funded in round
one of the U.S. Department of Energy's (DOE) Clean Coal Power
Initiative, a 10-year, $2 billion commitment to clean coal
technology. The program competitively seeks commercial-scale
technology demonstrations to continue and expand the use of
coal as a fuel source.
Barr's work on the pilot project has
included helping GRE develop the process, completing detailed
design for the prototype dryer, and assisting with prototype
installation. For more information, contact Dave Rian in Barr's
Hibbing office at 800-225-1966.
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