| OCR Text |
Show Steel Reheat Furnace, N e w York State This three zone, natural gas fired pusher steel reheat furnace w a s converted to LNI firing using the original hot air burners. Conventional parallel tiles were replaced with converging to increase the air velocity, and one external gas injector was added to each burner. The furnace is a 15' wide longitudinally fired configuration with 48' long, 7.5' high under and over-fired zones and a 28' long overtired soak zone. Zone Top Heat Bottom Heat Soak Burner Quantity 4 3 5 Nominal Capacity with 750F air at 6" w.c. 13.4 M M Btu/h each 18 M M Btu/h each 2.3 M M Btu/h each With a maximum heat input capacity of 120MM Btu/h and zone set points of 2300F, the furnace has a nominal production output of 80 t/h of 5.5" square billets to 2200F. Pre- and post-conversion furnace temperature profiles and emissions were recorded for this installation and are shown in Table 1. Of note are (a) the reduction in the soak zone temperature for higher average billet discharge temperature, (b) the sensitivity of N O x and C O to the furnace 0 2 content. Temp. Set Point Firing Rate % Zone Temp F Air Preheat F Av. Billet Temp F Refractory Temp F: Burner Wall Side Wall Emissions Corrected to 3%02 Soak Zone Pre-LNI 2300 40 2318 550-600 2160 2230-2270 Soak Zone Post-LNI 2275 40 2288 530-570 2194 2220-2270 Pre-LNI Post-LNI Post-LNI Top Heat Zone Pre-LNI 2300 2314 550-560 2260-2280 02 3.80% 1.20% 1.50% Top Heat Zone Post-LNI 2300 36 2298 530-570 2280-2300 NOx 224 ppmv 46 ppmv 73 ppmv Bottom Heat Zone Pre-LNI 2300 95 2320 550-600 2310-2320 CO 1 ppmv 728 ppmv 4 ppmv Bottom Heat Zone Post-LNI 2300 73 2308 530-570 2340-2350 16 |
