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Show INTRODUCTION Since early 1980, Riley Stoker Corporation has been actively involved with the development and testing of advanced low-NO burner designs for application to wall-fired and Riley Turbo furnaces. Extensive laboratory and field testing efforts aimed at reducing NO emisisons in existing wall-fired boilers led to the development of Riley's Controlled Combustion Venturi (CCV) burner (1). This burner design is presently installed in three full size utility wall-fired boilers and is now being offered on smaller industrial size furnaces. In response to the acid rain issue more stringent NO emission stan- 3 x dards may be enacted. The CCV burner in combination with air staging, is capable of meeting anticipated emissions standards in wall-fired furnaces. However, the application of advanced air staging in the Turbo furnace required the development of a new burner. Our objective was to develop a burner with more stable combustion characteristics at low burner zone stoichiometrics for Turbo furnace operation. The axial flow Directional Flame burner is utilized in current Turbo furnace designs. The Tertiary Staged Venturi (TSV) burner therefore was developed to replace the Directional flame burner under advanced staged conditions. The TSV burner was designed to provide flame stability with a medium degree of swirl. Aerodynamic tests were performed on plexiglass models of the TSV and Directional Flame burners. The aerodynamic model tests of the TSV burner showed that at medium swirl numbers 0.6-0.7 there was a small amount of recirculation. However, the bulk of the flow was axial, similar to the Directional Flame burner. The TSV burner has no expanding quarrel at the burner exit. The amount of recirculation, therefore, for a given swirl number is less than in the conventional circular burners (2). Combustion tests were performed to characterize the NO emissions and flame characteristics of the TSV. The results of these tests were compared to results of combustion tests on Riley Stoker's CCV burner (high 2 |