OCR Text |
Show 50% reduction in N0X emissions when excess oxygen was reduced from 3.0% to 1.0%. On the other hand, a 50/50 mixture of oil and gas resulted in an approximate 3% reduction in nitrogen oxides over oil firing. This reduction was probably due to the lower overall nitrogen content in the fuel mixture. The gas was analyzed to contain 0.0% nitrogen and the oil was found to contain 0.31% nitrogen. Figure 13 indicates N0X versus O2 data points while firing oil only, 50% gas and 50% oil firing, and gas firing only at elevated combustion air temperatures. Again, the firing of oil only showed a large dependence on excess oxygen, with an approximate 48% reduction in N0X emissions when excess oxygen was reduced from 3.0% to 1.0%. The firing of a 50/50 mixture of oil and gas continued to show an approximate 3% reduction in nitrogen oxides over oil firing. The most significant result in this case was that when firing oil only, or a 50/50 oil and gas mixture, with 600° F. combustion air, there was very little change in N0X emissions over those collected when using ambient combustion air. Furthermore, when firing the gas fuel only at the elevated temperature, the N0X emissions, in fact, decreased.approximately 37-43% below those in the ambient air tests. 12-32 |