【摘要】 为了研究低温等离子体在低温条件下辅助SCR降低柴油机NO_X排放过程中的作用机理,设计搭建了NTP-NH₃-SCR复合系统。在实验过程中,利用3个气体分析仪对NTP,NH₃-SCR系统、NTP-NH₃-SCR复合系统的净化效率进行独立测算,得到了3种净化系统对NO_X净化效率随温度变化的曲线。结果显示,在低于250℃的低温条件下,SCR对NO_X的净化效率较低,但在NTP的辅助下,能把NO_X净化效率从不高于40%提高到60%以上,且温度越低,NTP的加入对SCR降低柴油机NO_X的净化效率提高越明显。根据电晕放电理论,分析了NO_X流经NTP时产生的物理化学变化,结果表明,在低温工况下,NTP预氧化NO对SCR减少柴油机NO_X排放量有较大的促进作用。更多还原

【Abstract】 In order to investigate the reaction mechanism of non-thermal plasma in the process of assisting SCR to reduce NO_x emission of diesel engine at low-temperature condition, NTP-NH₃-SCR compound system is designed and built. In the experiment, three gas analyzers were used to measure the removal efficiency of NTP, NH₃-SCR system and NTP-NH₃-SCR compound system independently, and the curves of NO_x removal efficiency with temperature were obtained in three different systems. The results show that the removal efficiency of SCR for NO_x is low below 250 ℃, but SCR assisted by NTP can improve NO_x purification efficiency from 40% to more than 60%, and the lower the temperature is, the more obvious the purification efficiency of SCR reducing NO_x is. According to the theory of pulse corona discharge, the physical and chemical changes of NO_x flowing through NTP are analyzed. The results show that the preoxidation of NO by NTP can promote SCR to reduce NO_x emission obviously from diesel engine at lowtemperature condition.更多还原