Utility Boiler Operating Modes for Reduced Nitric Oxide Emissions

The information presented is directed to those individuals concerned with reducing nitric oxide (NO) emissions from gas- and oil-fired utility boilers, either as operators,manufacturers, or those having air quality management responsibilities.

The purpose of this paper is to present the results that are being obtained in a continuing program to reduce NO emissions from gas- and oil-fired utility boilers operated by the Southern California Edison Company. First, an understanding of NO formation and the controlling factors is presented, followed by a discussion of the combustion control techniques of ofF-stoichiometric combustion and reduced combustion temperatures. Results of field testing employing these techniques are demonstrated. Finally, boiler operating characteristics affecting NO and the implementation of the techniques for achieving operating reductions in NO emissions are discussed.