OCR Text |
Show Two reactions are chain propagation steps and are mainly responsible for NO removal: (40) NO + H02 -. N02+ OH (67) Reactions which increase and decrease NO concentration have positive and negative sensitivity coefficients, respectively. One can see that the reactions (40) and (67) have the highest impact on NO destruction. The reaction of OH and H02 interaction (39) removes the active species and is the main chain tennination process. Figure 5b is the NO sensitivity plot for the injection of CH30H at 1000 K. It is clear that this process has a more complicated mechanism than the H20 2 reaction. The rates of reactions No. 12, 13, 39, 43, 48, 49, 61, and 62 define the ratios between concentrations of the active species, OH, H02, and H. The main reactions with NO participation are NO + H02 - N02 + OH (67) H + N02 -. NO + OH (69) Methanol dissociates in flue gas yielding methyl and hydroxyl radicals which can react with CH30H molecules via (48) The CH20H radicals thus forrred are rapidly oxidized by O2 into CH20 and H02 (not shown in Figure 5b): (63) and the HO"- radicals react with NO to form NO"- via the reaction (67). Reactions (48), (63), and (67) are the main chain propagation steps in the CH30H/N0 chain interaction. Relative concentrations of active species (OH, H02, CH20H, and H atoms) define the effectiveness of NO removal. At 14 . |