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Show ( 3- ~ DESIGN & OPERATING OBJECTIVES OF LOW NOx BURNERS WHEN USED IN INDUSTRIAL PACKAGE BOILER APPLICATIONS Anthony Facchiano Coen Company ABSTRACT In recent years, much attention has been given towards the successful incorporation of basic NOx reducing mechanisms into the design of industrial burners. However, the potential negative consequences of low NOx burner modifications on system operability and efficiency remains a subject of much concern to all involved parties from the burner supplier to the end user. In the industrial sector, the success of a given low NOx burner design cannot be judged by NOx reducing abilities alone. Rather, the overall success of a given burner is a fu"nction of the burner's ability to achieve a given level of NOx reduction with minimal compromise to burner efficiency, stability, flame shaping flexibility, and system reliability. In the field of industrial package boilers, the inherent difficulties associated with high heat release rates, narrow furnace widths, and low furnace residence times provide the burner designer with combustion challenges independent of achieving NOx compliances. This fact, together with ever increasing regulations on allowable emissions of carbon monoxide, particulate, and unburnt hydrocarbons, make package boiler low NOx burner" design a formidable task. This paper will examine some of the many unique combustion problems facing the package boiler industry in achieving NOx compliances. The effects of implementation of basic NOx reducing mechanisms on system operability and performance will be discussed. The second generation OAF burner, an industrial low NOx burner developed by Coen Company with a primary design objective being minimal compromise to package boiler efficiency and operability, will be presented. Data from existing field installations will be displayed. OBSTACLES CONFRONTED IN PACKAGE BOILER COMBUSTION SYSTEMS The most common obstacles to the combustion process encountered in the design and operation of a package boiler include (1) high space heat release rates (with consequential low combustion chamber residence time), (2) narrow furnace widths, and (3) single burner operation. These parameters are discussed below: 1'. ~-e J~~;; ? STARTUP SUMMARY: JANUARY 1992 - JULY 1992 SECOND GENERATION OAF BURNERS NUMBER OF STARTUPS RANGE OF HEAT INPUT jBURNER RANGE OF SPACE HEAT RELEASE NO OF UNITS UNDER 75,000 BTUjHR-FT 3 NO OF UNITS BETWEEN 75,000-100,000 BTUjHA-FT 3 NO OF UNITS OVER 100,000 BTUjHR-FT 3 RANGE OF HEAT INPUT JFOOT WIDTH TABLE 1 27 26 TO 365 MMBTUjHR 52,(0) TO 138,(0) BTUjHA-FT 3 11 11 5 7 TO 43 MMBTUj HA-FT 1 ) ,I I I I, ( \ |
