OCR Text |
Show consistent with the results of Siebers and caton [4-6] and Perry [10], temperature is believed to be the most important parameter. Size Distribution Effects Temperature not only affects the reaction rate, but also . controls the sUblimation rate of the acid particles. Fine particles were more effective in removing NOx at low temperatures. The opposite was true for the coarse particles as shown in Figure 9. Thus, as the particle size distribution varies, temperature should also change accordingly to maximize NOx reduction. CONCLUSIONS Performance of pulverized cyanuric acid as a NOx reducing agent was examined in an oil-fired industrial-scale furnace. Species concentration at the stack were measured before and after the injection of cyanuric acid. Significant reduction in NOx was measured without any burner adjustments. Although the process shows some sensitivity to the concentration of excess oxygen, its presence does not terminate NOx removal. Based on limited injection temperature variations, maximum NOx reductions ranged from 70 to 80% at 3.2 and 5.4% excess oxygen, respectively. Temperature was determined to be the most important parameter. Another important consideration is powder size selection which is also coupled with temperature. Finer powders are more effective at low temperatures, while coarser particles are suitable at high temperatures. Presently, the fate of the removed NO and its conversion to N2 or N20 is unresolved. Additional tests which include N20 measurements are needed to elucidate the issue. ACKNOWLEDGMENTS The authors would like to thank Gene Stoffer and vic Burgess for their assistance in test setup and instrument operation. -5- |