OCR Text |
Show 11 Table 2. NOx emission factors and nitrogen balance. Rice Waste Wood Humus Straw Paper Wood Blend NOx emission factor (% dry fuel as N02) ¢= 0.30 1.00 0.90 0.15 0.30 0.25 ¢= 0.85 0.10 0.40 0.19 0.17 N emission as NOx (Ok dry fuel) ¢=0.30 0.30 0.27 0.05 0.09 0.08 ¢= 0.85 0.03 0.12 • 0.06 0.05 Fuel N (0/0 dry fuel) 1.21 1.00 0.35 0.12t 0.62 NOx emission (gig fuel N) ¢=0.30 0.83 0.90 0.43 2.50 0.40 ¢= 0.85 0.08 0.40 • 1.58 0.27 NOx Nlfuel N (%) ¢=0.30 25 27 13 76 12 ¢= 0.85 3 12 48 8 i not measured. tunconfirmed. humus and the wood-straw blend. In the case of the wood-straw blend, the range was exceeded at ¢ = 0.8, and the value for if> = 0.85 was simply extrapolated. The value was not extrapolated for the humus fuel, as the instrument range was exceeded much earlier at ¢ = 0.6. The CO concentrations increased quite sharply above if> = 0.85 with rice straw. The value at ¢ = 0.87 is reported in Table 3 to indicate this. The behavior is apparent in Figure 5. Included in Table 2 are the emission factors for NOx, along with a nitrogen balance yielding relative nitrogen emission as NOx. NO accounted for greater than 90% of NOx in all cases. Separate N20 determinations were not made. At ¢ = 0.30, the nitrogen emission in NOx represents from 12 to 76% of fuel nitrogen, although an actual conversion fraction cannot be calculated due to unquantified contributions from thermal or prompt NOx. The Douglas fIT wood has a high relative NOx production compared to the other fuels. There is some question as to the accuracy of the nitrogen concentration for this fuel, and the determination is being repeated. The decrease in NOx emission at higher equivalence ratios is apparent in the table. In the case of the high nitrogen fuels, humus and rice straw, the reduction is substantial. |