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Show 1990 AFRC Int'l Symposium illustrate a portion of the study's results. Figure'2 offers a graphical representation of the reaction system NO/02/C12 as a function of residence time, at 300 K and the following inlet ratios, 1:50:2.5, respectively (these inlet ratios are similar to those experienced in practical combustion situations). Figure '3 shows results of the same ratio, fixed at a reactor residence time of 3 seconds, at various temperatures. Figure #4 demonstrates the effect C12 has on the final product mixture ratio. This study produced two interesting findings. First, at a wide range of conditions, oxidation of NO by 02 is several orders of magnitude larger than accomplished by C1 2 . This indicates that, although the NOCI reaction constant is relatively large, the reaction is limited by the small concentration driving force. Therefore, the presence of any C12 in the reaction mixture should not have had a very large impact on the removal efficiency, if the removal mechanism were gas phase. Second, a combination of both of these reactions paths could not account for the experimental results achieved in the earlier work. The early study [Tamony, Youngson. 1981] cited removal efficiencies of greater than 90% of inlet NO concentration . At best, these two reaction schemes could account for less than 20% of the NO removed during the cited earlier studies, this assuming the scrubbing system that followed the reaction zone removed 100% of all oxidation products (N02 and NOCl) . Based upon the above information, the final conclusion of the gas-phase study is that the reactions responsible for the NO reduction exhibited in the system were not significantly affected by any gas-phase reaction scheme. NO o x i dat i on vs. res i dence time 100 . 0000 10 . 0000 .c u t1l (1) Vl .... (1) 1.0000 o ~ .... u (1) '0 0. (1) Vl 0 . 1000 :EVll ~U C :l o '0 u .0... 0 . 0100 0 0. Z -Noel -- - --- dP 0.0010 --- 0 . 00 01 0 . 0 1.0 2. 0 3.0 4 . 0 5 .0 6 .0 7. 0 Re side nce time, sec Figure 2 Transport/chemistry at the gas-liquid interface in the scrubber Since a gas-phase reaction involving C12 could not account for the significant reductions in stream NO concentrations occurred after C12 was injected into the system, attention was turned to the scrubbing system located immediately after the C12 addition point. A variety of aqueous scrubbing fluids were used during the investigation. Samples of the results of the test are displayed in Figures #5,#6,#7,#8,#9, and #10. The variable "1t" is the inlet molar ratios of C12 to NO. The plots, in all cases, represent measurement of the system's outlet stream NO concentrati ons and pH l evels of the scrubber fluid. The plots are all on a -4- |
