C2H4对臭氧氧化NO影响的试验研究

用管式反应器试验研究了碳氢对臭氧氧化NO的影响．试验在不同反应温度、[O3]／[NO]摩尔比以及碳氢浓度下进行．结果表明，C2H4对NO氧化成NO2有促进作用，在275℃时，NO氧化率和N02生成率有较明显提高．在[03]／[NO]=0．6，反应温度分别为常温、200℃和275℃时，加入400×10^-6C2H4，NO2生成率由56．5％、55．9％和38．0％分别提高到62．1％、60．0％和42％．在试验中，检测到了CO，当[O3]／[C2H4]为1．0时，在常温、200℃、275℃下，体系中CO浓度小于30×10^-6，说明C2H4确实参与了反应．C2H4对NO氧化的促进作用的机理是：在275℃时，臭氧分解速率显著提高，在氧存在的气氛下，烯烃易与O3反应，反应产生了更多活性很强的自由基（CH3O2、OH、HO2）等，而这些自由基均可与NO反应，从而弥补了由于臭氧自身分解的加速使NO氧化率的下降，即在加入C2H4后，在温度较高时仍能达到NO的较高氧化率．

Experimental Study on Effect of C2H4 on Oxidation of NO by O3

At different reaction temperature and [O3]/[NO] molar ratio with and without C2H4, the experiments are carried out in a tube reactor located in a tube furnace to investigate the influences of C2H4 on the oxidation of NO by O3. The experimental results reveal that C2H4 facilitates the conversion of NO to NO2. The addition of 400×10^-6 C2H4 increases the yield of NO2 from 56.5%, 55.9% and 38% to 62.1%, 60% and 42%, at ambient temperature, 200 0（2 and 275 ℃, respectively, with the same [O3]/[NO] ratio （[O3]/[NO]=0.6）. The reactions between C2H4 and O3 produce some strong oxidative radicals such as CH3O2, HOE, which can oxidize NO to NO2.