EERC Technology Greatly Improves Power Plant Efficiency
Wednesday, February 11, 2004
(GRAND FORKS, N.D.) - Researchers at the University of North Dakota (UND) Energy
& Environmental Research Center (EERC) have made major strides to improve
the efficiency and dramatically reduce emissions of coal-fired power plants by
burning a combination of pure oxygen and coal to generate electricity in an
advanced power system. The material used in the system is the same alloy used to
make F-16 fighter jet engines, and it is the first time it has been used in a
coal-fired power system.
In a demonstration project conducted at the EERC, a natural gas- and coal-fired
system was used to test a very-high-temperature heat exchanger, which is the
heart of an advanced high-efficiency power plant - otherwise known as an
indirectly fired combined cycle (IFCC). It could hypothetically have no
emissions whatsoever.
"Results of previous demonstrations while firing with air prove that the
efficiency of a power plant using this technology could improve by about 30%,
resulting in cheaper, cleaner energy," says EERC Senior Research Manager
John Hurley.
Today's power plants burn coal and air to heat water into steam, which is blown
through a turbine and turns a generator making electricity. A power plant using
IFCC technology heats air to a much higher temperature in the heat exchanger and
uses the hot air to turn the turbine resulting in a significantly higher
efficiency. The EERC has used the system's heat exchanger to produce air at 2000
dagrees.
"This technology offers a potentially cost-effective method to enhance
efficiency, reduce emissions, and contribute to a cleaner, healthier environment
worldwide," said EERC Director Gerald Groenewold.
Air is over three-quarters nitrogen. The benefit of using pure oxygen is that by
excluding nitrogen from the flame, fewer pollutants are produced (reduction as
much as 50% of NOx) and the volume of gas is reduced so the plant can be much
smaller and less expensive to construct. In an oxygen-enriched system, the flue
gas consists almost totally of water vapor and carbon dioxide, making them much
easier to collect and store or reuse within the plant.
"If a time comes when taxes are imposed on carbon dioxide emissions, it
will be very important to remove the CO2 from the gas stream and sequester it,
and that will be much easier if the system is fired with oxygen rather than
air," says Hurley.
While the EERC system has been tested with several types of coal, it can also be
configured to use a variety of fuels such as biomass (fast-growing trees and
grasses, and municipal waste) or liquid fuels. Through the Xcel Energy Renewable
Development Fund, the EERC has recently completed tests using 20% biomass. In
addition to the Xcel funding, much of the work is funded through the U.S.
Department of Energy (DOE) and managed through the DOE National Energy
Technology Laboratory.
For more information, contact:
Tom Erickson
Associate Director for Research
Energy & Environmental Research Center
15 N. 23rd St.
PO Box 9018
Grand Forks, ND 58202-9018
terickson@undeerc.org
Web site:
www.undeerc.org