汽车尾气中NO_X再燃烧过程的动力学

Kinetics of NO_X reburning processes in exhaust gases

为了阐明汽车尾气中 NOX再燃烧的动力学进程 ,以甲醛和 NO2 作为探针分子 ,通过 FT-IR跟踪研究了反应体系中所产生的 HCO自由基与 NO2 反应的动力学。结果表明 ,反应的主要产物中包括 CO、CO2 、NO、HONO和 H2 O等分子 ,经长时间的反应 ,当体系中的 NO2 基本耗尽时 ,才有少量的 N2 O生成。这些产物分子分别是在几个不同途径的连串反应中形成的。从体系中 CO和 CO2 的生成量 ,测定了主反应的歧化反应速率比 ,并对相应的动力学机理进行了讨论。

In order to explore the kinetic mechanism of NO X reburning processes in exhaust gases,HCHO and NO 2 were used as probe molecules.The HCO radicals were generated in the reaction system,and the kinetics of the reaction between HCO radicals and NO 2 was investigated by FT IR spectroscopy.It showed that the main reaction products including CO,CO 2,NO,HONO and H 2O were detected.A small amount of N 2O was found only at long reaction times when the NO 2 consumption was complete. These molecules were formed in consecutive reactions from several reaction channels.From the yields of CO and CO 2,branching ratios were determined and their kinetic mechanism was discussed.