Government-Funded Utility Software Curtails NOx Emissions; Gains Foothold in U.S. and U.K. Markets

Neural Network Optimizes Coal Burner Performance

New software that can automatically reduce nitrogen oxide (NOx) emissions and improve the performance of fossil fuel-fired power plants is one of the latest success stories emerging from the Department of Energy's (DOE) Fossil Energy research program.

The software, an outgrowth of the burgeoning field of artificial intelligence, has been successfully tested by Southern Company Services, Inc. in the DOE Clean Coal Technology Program and is now being installed commercially at six power plants in the United States and the United Kingdom.

The computer program is called the Generic NOx Control Intelligent System, or GNOCIS. It uses a neural network model of boiler operating parameters - particularly those that affect NOx emissions and boiler efficiency- to allow utility operators to automatically optimize plant performance and, correspondingly, reduce fuel consumption at a very low cost.

GNOCIS was first used to reduce emissions and optimize overall performance at several coal-fired utility boilers equipped with low-NOx burners; however, additional early demonstrations include other fossil fuel-fired units and the project team is currently looking at GNOCIS as a means to optimize post-combustion NOx control systems, such as selective non-catalytic reduction and selective catalytic reduction.

In addition to DOE and the Southern Company, partners in the development of GNOCIS are the Electric Power Research Institute (EPRI); Radian International; PowerGen (a major U.K. utility); and the U.K. Department of Trade and Industry.

Prior to funding under the Clean Coal Technology Program, DOE's Federal Energy Technology Center co-sponsored an early evaluation of GNOCIS at Alabama Power Company's Gaston 4 unit, a 270-megawatt wall-fired boiler. DOE then agreed to support the testing of the EPRI-owned GNOCIS software as an expansion of Southern Company's Clean Coal Technology Program project to demonstrate advanced combustion techniques for wall-fired coal boilers at Georgia Power Company's Plant Hammond in Coosa, Georgia. Alabama Power and Georgia Power are subsidiaries of the Southern Company.

Although Plant Hammond met NOx emission limits after retrofitting low-NOx burners as part of the Clean Coal Technology project, the performance was adversely impacted by the installation of the low-NOx technologies. At this site, GNOCIS is being used to maximize boiler efficiency while maintaining NOx below compliance limits. In addition to the Gaston and Hammond demonstrations, the U.K.'s PowerGen installed GNOCIS at its 500-megawatt Kingsnorth 1 unit as a demonstration on a tangentially fired boiler. The Kingsnorth demonstration also focused on reducing unburned carbon in fly ash to improve the plant's operating efficiency and economics.

Prior to the GNOCIS installation, the Clean Coal Technology demonstration project at the 500-megawatt Unit 4 at Plant Hammond evaluated the long-term performance of three advanced combustion techniques to reduce nitrogen oxides. These techniques -- advanced overfire air, low-NOx burners, and a combination of the two -- reduced NOx emissions by about 35, 45, and 65 percent, respectively.

Following installation of GNOCIS, initial testing in early 1996 showed that the software increased Plant Hammond's boiler efficiency by one-half of a percentage point, reduced unburned carbon in the fly ash by one to three percentage points, and reduced nitrogen oxide emissions by 10-15 percent at full load over and above the reduction achieved using the low-NOx burners and advanced overfire air system installed during the Clean Coal Technology project.

Southern, along with Radian, are currently installing GNOCIS in six other U.S. power plants on a commercial basis, including several Southern units. The following plants have installed GNOCIS during the last few months, or are about to have it installed: Southern's Branch 3, Wansley 1, and Gaston 3 units; Duquesne Light's Cheswick unit; Entergy's Nelson Unit 4; and PowerGen's Kingsnorth 3 unit. Of the 9 current GNOCIS installations, five units burn coal, one burns gas, one burns a combination of coal and gas, and two burn a combination of coal and oil. These units also encompass a wide variety of boiler firing types, including those of the major U.S. boiler manufacturers.

Following the successful installation of GNOCIS in these units, the project team anticipates a total of about two dozen installations by year's end, and is negotiating several installations in foreign countries.

- End of TechLine -

For More Information:
Hattie Wolfe, Office of Fossil Energy, 202-586-6503, e-mail: hattie.wolfe@hq.doe.gov

Scott M. Smouse, DOE Federal Energy Technology Center, 412-892-5725, e-mail: smouse@fetc.doe.gov