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Show CONCLUSIONS AND RECOMMENDATIONS CONCLUSIONS A series of experiments were performed in order to evaluate the capability of alkaline NaCl02 aqueous solution to oxidize and absorb NO. In some runs, N02 or 02 were mixed with NO and N2 to simulate a flue gas emitted by municipal incinerator or stationary power plant. The conclusions from this research are: * * * * * * * * * At room temperature and atmospheric pressure, NO is not absorbed by distilled water. NaOH up to 1.0 molar does not improve this absorption. At room temperature and atmospheric pressure, N02 can be absorbed effectively by NaOH in aqueous solution. A 0.5 molar NaOH in aqueous solution can scrubb 98% of N02 from flue gas at relatively low N02 concentration (lower than 800 ppm). The effectiveness of NO absorption in caustic aqueous scrubbing is greatly increased by the presence of N02 in the flue gas. 5% 02 in flue gas does not affect NO absorption in caustlc (NaOH up to 1.0 molar) aqueous scrubbing. NO can be oxidized effectively by NaClO in aqueous solution. During scrubbing, NO is oxidize~ to N03-, and Cl02 - converted to Cl-. Owing to the production of HN03 , pH drops sharply from 10 to 3 within ten minutes in the scrubbing of NO by alkaline NaC!02 aqueo~s solut~on .. Rates of Cl and N03 formatlon ln scrubbing solution are constants as the concentration of NaCl02 changes from 0.008 molar to 0 molar. At concentration ratios of NaCl02 to NaOH below 8 the effectiveness of NO absorption in NaCl02 aqueous scrubbing solution is increased by about 7%. However, at concentration ratios higher than 8 decreases or inhibits its absorption. This is a consequence of the solution not becoming acid. Effectiveness (NO/Cl02- ratio) decrease from 0.95 to 0.84 when 5% 02 in presence of flue gas. RECOMMENDATIONS The results of this research clearly indicate the utility of NaCl02 for NOx emission control. The best conditions of chemical reactlon of NOx in NaCl02 and aqueous scrubbing can be reached from the results presented in this paper. However, to develop the engineering data ·that is essential for scale-up, pilot plant studies are needed. A bubbling reactor can tolerate a much higher pressure drop than a conventional scrubber. Some critical factors which need to be studied in pilot plant process are: * * Rate of NO absorption in alkaline NaCl02 aqueous solution under countercurrent conditions. Overall mass transfer coefficient and interfacial area 14 |