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Show Mr. John Sorge GNOCIS - A TOOL FOR CONTINUOUS COMBUSTION OPTIMIZATION OF UTILITY BOILERS Mr. Bill Menzies Radian International LLC Mr. Jeff Stallings Southern Company Services Electric Power Research Institute ABSTRACT GNOCIS (~eneric tIDx Controllntelligent System) is a methodology that can result in improved boiler efficiency and reduced NOx emissions from fossil fuel fired boilers. Using a numerical model of the combustion process, GNOCIS applies an optimizing procedure to identify the best set points for the plant on a continuous basis. The optimization occurs over a wide range of operating conditions. Once determined, the recommended setpoints can be implemented automatically without operator intervention (closed-loop), or, at the plant's discretion, conveyed to the plant operators for implementation (open-loop). GNOCIS is designed to run on a stand-alone workstation networked to the digital control system, or internally on some digital control systems. The developmental sites for GNOCIS are Alabama Power Company's Gaston Unit 4, a 270 MW wallfired unit, and PowerGen's Kingsnorth Unit 1, a 500 MW tangentially-fired unit. This paper provides a general overview of the technology and results from testing at these two locations. In addition, GNOCIS is also being installed on other utility boilers and results will be presented from these sites as available. The development of GNOCIS was funded by a consortium conSisting of the Electric Power Research Institute, PowerGen, Southern Company, Radian International, U.K. Department of Trade and Industry, and U.S. Department of Energy. INTRODUCTION Deregulation of the industry has forced utilities to improve operating efficiencies of their units in an effort to reduce overall operating cost and become more competitive. Also, passage of the 1990 Clean Air Act Amendments has challenged U.S. electric utilities to reduce nitrogen oxide (NOx) emissions and to maintain these low emission rates during day-to-day operation. Boiler efficiency, fly ash carbon-in-ash (CIA or LOI), and NOx emissions are strongly influenced by a number of controllable and uncontrollable operating parameters. Due to the combustion complexity and high coupling of a number of important process parameters associated with boiler combustion -especially for pulverized coal fired units -- it is difficult to obtain an optimum or even acceptable operating point. When one operating parameter is improved, another is usually adversely affected. Therefore, delicate balancing is needed to maintain the optimum over a wide operating range and for extended periods. The difficulty in optimization is compounded on units with low NOx combustion technologies installed. AFRC 1996 International Symposium September 30 - October 2, 1996 |
