EERC Technology Greatly Improves Power Plant Efficiency

From Energy & Environmental Research Center
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