OCR Text |
Show w o CO o ® s w</) E 5? Q. O X oz 90 80 70 60 50 40 30 20 10 - - - Preheat190°F """"••-v.. I Full Load, -20% FGR >*. ® ^ N . Preheat 400°F ""/#\ Ns, I I I 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Excess 02, % Figure 8: EV Burner NOx: Excess 02, Preheat Temperature Variation DISCUSSION Program test results confirmed that the main parameter for controlling NOx formation is temperature. It was found that burner variables influencing natural gas flame temperature have the biggest impact on NOx emission levels. Figure 9 illustrates the combined effect of these parameters on the calculated adiabatic flame temperature and the resulting experimental NOx levels. c 0) > X O •o 0) •f o 0) l_ l_ o o E Q. Q. X O z 100 90 80 70 60 h 50 40 h 30 20 10 \- 0 8% 02* J I L • Note: Cold Walls No FGR & No FGR Hot Walls $ 13-15% FGR 22-26% FGR 20 40 60 80 100 8,040 24,100 40,200 56,270 72,350 Facility Load, Million Btu/hr Volumetric Release Rate (Btu/hr/cu ft) Figure 9: Low Nox Venturi Burner Natural Gas Test Results NOx Versus Facility Load 12 IV-24 |