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Show 100 - so . 60 . 40 . 20 . 0 Firing Rate: 250,000 Btu/h - Excess Oxygen: 3 % _ \ ' ^*^--~-*-^ • X k NOx < » Heat Transfer - . CO I 1 1 1 1 1 .. 80 Frequency (Increases to right) .. 60 O 40 s? -- 20 9- Figure 5. RESULTS WITH NOZZLE-MIXED HOT AIR BURNER (AMBIENT AIR) 100 .. « 80 .. in o Z 60 .. 40 .. - 20 i O z Firing Rate: 2,000,000 Btu/h Excess Oxygen: 5% / Frequency (Increases to right) Figure 6. RESULTS WITH TUBE-IN-TUBE OXY-GAS BURNER 100 80 60 40 20 0 4 y _ _^ ^ _ N Ox -•- Heat Transfer 500,000 Btu/h 810°F combustion air 3% O, in exhaust 160 120 80 £ 40 Frequency (increases to right) Figure 7. RESULTS WITH BAFFLE BURNER (HOT AIR) 100 80 2 60 40 20 jf / X s -*-NOx -•- Heat Transfer ^_^^a 500,000 Btu/h 3% O. in exhaust 29% 0 2 in air 250 200-- CD a 150 5" 100. 50 Frequency (Increases to right) Figure 8. RESULTS WITH BAFFLE BURNER (ENRICHED AIR) FIELD EVALUATIONS Two field evaluations have been completed. One was on an oxy-gas-fired rotary iron melter and the other was on a ladle preheater. Both of these efforts were lead by Air Liquide. Two additional field evaluations are currently underway. IGT is leading the effort on a batch annealing furnace, while Air Liquide is leading the effort on an oxy-gas-fired glass melter. More field evaluations are planned. Rotary Iron Melter Field Test Oscillating combustion field tests were performed on a 5-ton capacity rotary iron melter foundry located in the Northeast. The foundry produces castings for machine tools. The iron grades produced include C40 gray, ductile, and Ni-hard castings. In February 1992, Air Liquide converted the above foundry operation from air-fuel to 100% oxy-fuel operation. Overall, the conversion (the first rotary furnace at that time outside Europe operating on oxy-fuel combustion) was very successful7. Figure 9 shows a schematic drawing of the rotary melter used for testing. The nominal 3628 kg. The melter has a door that swings open, and the burner is mounted on this door. The burner is an Air Liquide MF-6, water-cooled burner rated at 7 M M Btu/h (2 M W ) . The burner uses six individual flamelets to create the overall flame. There is a gap between the door and the melter body where a large infiltration of ambient air takes place. This is the main source of nitrogen for NOx formation. (afrc98pdoc) 5 |
