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Show Table 3 AVERAGE OPERATING DATA - 1990/1991 FIELD EVALUATION TESTS FGR + NGas At Normal At 1987 Normal Base line 1991 Basel ine FGR Only MSW Input Baseline 1987 1991 (Average (Average MSW Input ~ Test Date) Date) Test MSW. s Ib/h 6.450 7.760 6,500 7,000 Natural Gas. % 0 0 0 14.0 12. 4 Total Heat Input. S 10 6 Btu/h 33.5 40 . 3 39.9 41. 9 FGR. " 0 0 9.5 9.5 10. 0 Excess Air. " 73 76 54 37 41 Total Flue Gas, S Ib/h 44.800 54. 100 47.100 45.400 48,500 Steam Flow. Ib/h 23.500 28.250 27.670 29,000 30,500 Economizer Exit Temperature, 0 F 417 425 423 422 422 Precipitator Inlet O2 , % 9.3 10.5 7.6 6.5 5.9 CO, ppm at 12" O2 30 46 47 22 21 NOx. ppm at 12% O2 135 117 70 48 48 * Estimated Table 3 shows test results under vlrious conditions and timeframe, i.e. 1987 basel ine data col leciton time; 1991 basel ine operation and with Flue Gas Recirculation (FGR); FGR and natural gas injection on 1987 MSW base and 1991 base. (Due to I imitation set by the steam demand, natural gas injection automatically reduced MSW, throughput. (1) Gene ra II y speak i n9, resu I ts of the pi lot-sea I e tests and those of the fie I d tests coincided with each other. (2) By injecting natural gas equivalent of 12% to 15% MSW heat value, NOx was reduced to 50 ppm (60% reduction), and CO to 25 ppm (50% reduction). (3) Also, it enabled reduction of excess air rate from 70%-80% to 40%. (4) For transporting the natural gas, and mixing and swirl ing it inside the furnace 6% to 8% of flue gas should be recirculated. (5) As excess air rate can be reduced, steam generation can be increased in proportion to the heat input of natural gas whi Ie MSW throughput was kept at the basel ine level. 8 |