OCR Text |
Show percent, respectively. None of these tests produced appreciable amounts of CO. The THC emissions from tests 4 and 7 averaged 21 ppmvw, and the destruction efficiencies were >99.996 percent. There were no DRE results available for the baseline test. Test 9 on the advanced burner was conducted at similar conditions to the first baseline test (see Figure 4). Both were performed in an uninsulated furnace firing No.2 fuel oil with about 2800P air preheat. However, the baseline test firebox temperature was 1,880oP, compared to 1,450°F in test 9. The NOx emissions data for the two tests were similar, as seen in Figure 4. The CO and THC emissions also did not differ significantly. The DRE was not measured for test 9. The similarity in the NOx emissions is not surprising since the primary benefit of the advanced burner is to reduce the rate of formation of fuel NOx• Since the No.2 fuel oil has almost no fuel-bound nitrogen, the emissions are from thermal NOx, and only a slight reduction is obtained with the advanced burner. Conversely, on the No.6 fuel oil tests, there is more fuel NOx formed, and the benefit of employing the advanced burner is more apparent. The difference in the performance of the two burners should continue to increase as the concentration of the fuel-bound nitrogen increases. Tests 8 and 10 were performed on No. 2 ~el oil to gather additional information on the performance of the advanced burner. The conditions for test 8 were the same as for test 9 with the exception that ambient combustion air was used. This caused the corrected NOx emissions to decrease to 54 ppm. Test 10 was conducted at the same conditions as test 8, but without staged fuel firing to determine the impact of firing No.2 fuel oil with a minimum amount of natural gas firing. The NOx emissions did not change, but the CO concentration increased slightly from 4 to 24 ppmvd. Tests 11 and 12 were performed firing No. 6 fuel oil without natural gas firing. Test 11 used ambient combustion air at a firing rate of 15 MMBtu/hr, while test 12 was conducted with 290°F air preheat and 20 MMBtu/hr heat input. The NOx emissions measured during test No.2 are presented in Figure 5 along with the results 12 |