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Show Since thermal NOx usually contributes a significant fraction of the total NOx when burning oil, control of thermal NOx is also important. Techniques for controlling thermal NOx with oil are similar to gas and include FGR, reduce air preheat, etc. GAS/OIL BURNER DESIGN PROCEDURE This procedure was used to design a dual fuel gas/oil low NOx burner. The input design criteria were as follows: 1. Gas or Oil fuel, 2. Maximum thermal input of 2.5MW, 3. Minimum air pressure 500 mm H20, 4. Gas pressure of 1 atm., 5. Oil, steam pressure of 10 atm., 6. 0.3% nitrogen oil, 7. Ambient air. The desired burner performance in order of importance was: 1. Stability over 5/1 turndown range, 2. NOx emissions less than 30 ppm on gas less than 80 ppm on oi 1 , 3. CO less than 50 ppm, 4. Compact flame. STABILITY DESIGN PROCEDURE An example of the flow and recirculation streamlines predicted by the isothermal inviscid model are shown in Figure 3. These calculations were for a geometry and swirl level which should give the desired flame stability over the 5/1 turndown range. -8- |