论文部分内容阅读
对主要在北京行驶的总里程在34×104～59×104km的6辆轻型出租车用三效催化剂,利用X射线荧光光谱仪(XRF)分析了其表面元素的种类、含量,以及污染物元素含量与行驶里程的关系.结果表明,在催化剂表面检测到的元素种类近30种,含量较高的元素种类基本相同.前后级催化剂上检测到的共同污染物元素有P、Ca、Zn和Mn等,主要来自于机油和汽油,34×104km行驶里程后,P在催化剂的累积速度已非常缓慢,Ca、Zn和Mn在催化剂表面的沉积经过56×104km后仍有增加的趋势.在后级催化剂上还检测到了明显的S含量,说明S更容易在后级催化剂上沉积.经过40×104km行驶里程后,S在催化剂表面的沉积量基本达到平衡状态.累积规律说明经过40×104km行驶里程后,容易使催化剂中毒的P和S对催化剂活性影响已较小,而Ca、Zn和Mn的持续累积,将会继续降低催化剂的活性.
Six light taxis with a total mileage of 34 × 104 ~ 59 × 104km were mainly used in Beijing. Three-way catalysts were used to analyze the types and contents of the surface elements and the content of pollutant elements by X-ray fluorescence spectrometer (XRF) The results show that there are nearly 30 kinds of elements detected on the catalyst surface, and the kinds of elements with higher contents are basically the same. The common pollutants detected on the front and the rear class catalysts are P, Ca, Zn and Mn , Mainly from oil and gasoline, the accumulation rate of P in the catalyst has been very slow after the 34 × 104km mileage, and the deposition rate of Ca, Zn and Mn on the catalyst surface still increases after 56 × 104km. Also detected a significant S content, indicating that S is more easily deposited on the rear catalyst after 40 × 104km mileage, S deposition on the catalyst surface basically reached equilibrium. The cumulative law shows that after 40 × 104km mileage , P and S which are easily poisoned by the catalyst have little effect on the activity of the catalyst, and the continuous accumulation of Ca, Zn and Mn will continue to reduce the activity of the catalyst.