O_2和NO_2气氛下柴油机炭烟氧化过程及其化学反应动力学参数研究

Research on Diesel Soot Oxidation Process and Chemical Reaction Kinetic Parameters in O_2 and NO_2 Environment

用热重分析仪对O_2和NO_2气氛下柴油机炭烟的氧化过程进行了试验研究,并利用程序升温氧化(TPO)试验对其化学反应动力学参数进行了研究,建立了O_2和NO_2气氛下柴油机炭烟氧化过程的化学反应动力学模型,并用模型对O_2和NO_2对炭烟的氧化效果进行了对比分析。研究结果表明:柴油机炭烟在O_2气氛下大约从700K时开始氧化,氧化反应的活化能为76.8kJ/mol,对O_2的反应级数为0.85;而在NO_2气氛下大约从600K时开始氧化,氧化反应的活化能为21.9kJ/mol,对NO_2的反应级数为0.85。在柴油机排气组分条件下,当温度低于750K时,NO_2氧化炭烟引起的炭烟质量减少占主导;而当温度高于800K时,O_2氧化炭烟引起的炭烟质量减少占主导。

The diesel soot oxidation processes in the environment of O 2 and NO2 were researched with thermogravimetric ana‐lyzer ,the chemical reaction kinetic parameters were analyzed by temperature programmed oxidation test ,the chemical reaction kinetic model of diesel soot oxidation process in the environmentof O2 and NO2 was established ,and the soot oxidation effects of O2 and NO2 were compared and analyzed with the model .The results show that the diesel soot begins to oxidize at 700 K and 600 K and the oxidation reaction activation energy is 76 .8 kJ/mol and 21 .9 kJ/mol in the presence of O2 and NO2 respectively ., The reaction order of O2 and NO2 are both 0 .85 .In the exhaust of diesel engine ,the soot mass reduction depends on NO2 oxi‐dation reaction below 750 K ,but on O2 oxidation reaction beyond 800 K .