| OCR Text |
Show Table 6 Operating Data with Natural Gas Injection Item Unit Operating Data Remarks MSW Flow tl24h MSW Heating value kcal/kg Combustion Air Flow Nm~ih Exhaust Gas Flow Nm=/h 0 , % dry Na tural Gas Flow m='1h Figure 3 show the relationship between NOx and CO with reburning oper-ation. Under normal operation, NOx was 1 20-1 40ppmand CO was 40-70ppm, corrected to 1 2% Oz. Adding recirculating gas which enables mixing and swirling inside furnace, lowered NOx to 80-11 Oppm. CO density, however, remained at the same level. Reburning operation which adds natural gas to the recirculating gas, further reduced NOx and CO simultaneously by 50%. If taken separately, it \t\./as possible to operate at NOx below SOppm, and CO below 10ppm 5.3 The effect of natural gas injection location and volume Since reburning system uses natural gas injection to form a reducing zone which removes NOx, the selection of nozzle locations becomes an important factor. 66.1 1,490 5,300 3,100 12,400 160 140 120 c5 # 100 cu E Cl Cl d 80 z 60 40 20 11.5 30 o 0 LHV Under-Grate Air Overfire Air Dry Gas IDF Inlet )( ...... ~I "fGII_~ o o~~~ __ ~~~ __ ~~~~ o 10 20 30 40 50 60 70 80 90 CO{ppm 12% 0,) Figure 3 Relationship between NOx and CO Concentration Figure 4 displays the correlation between the injection nozzle location and NOx, CO reduction. In this furnace, 0= density was higher at the rear, and injecting natural gas from the back of the furnace showed better results. It was also witnessed that the more natural gas was injected, the greater the NOx reduction effect became. However, due to large variances in the combustion corr dition within the furnace, we could not obtain sufficient data to analyze the relatiorr ship between the natural gas volume and the NOx removal ratio. Within this limitation , we could obtain 50% reduction of NOx and CO by using natural gas volume equi- 7 |
