车用尿素水溶液(AUS 32)中金属离子检测方法分析  

Analysis of Detection Methods of Metal Ions in Vehicle Urea Aqueous Solution(AUS 32)

作　　者：王亚雄 Wang Yaxiong(Beijing Chemical Product Quality Supervision and Inspection Station,Beijing 100089,China)

机构地区：[1]北京化工产品质量监督检验站,北京100089

出　　处：《广东化工》2022年第16期207-209,197,共4页Guangdong Chemical Industry

摘　　要：车用尿素水溶液中对金属离子(钙、铁、铜、锌、铬、镍、镁、钠、钾、铝)的控制是为了避免对SCR系统催化剂产生毒害作用,避免影响SCR系统中对氮氧化物还原的转化效率,也应严格控制其含量。为了更方便快捷检测车用尿素水溶液中对金属离子的含量,本实验在国家标准GB 29518-2013柴油发动机氮氧化物还原剂尿素水溶液(AUS 32)的基础上对灰化法、直接进样法两种样品前处理方法进行了对比。通过对直接进样法和灰化法检出限、准确度和精密度的分析对比,结果表明:灰化法所测除Zn外所有元素浓度均在其相应检出限的3倍以上,直接进样法中Al、Zn、Na、K四种元素测定浓度均低于3倍检出限,说明灰化法相较于直接进样法测得的数据更加真实有效;通过进行加标回收实验,结果显示直接进样法的加标回收率高于灰化法,说明直接进样法具有更高的准确度;通过计算RSD,结果显示直接进样法和灰化法RSD接近,说明这两种方法的精密度比较接近。综合考虑两种方法:灰化法前处理过程繁杂,石英坩埚消耗巨大,成本较高,对实验人员,实验环境要求很高,但是所测得的结果更真实有效;直接进样法方便快捷,节约成本,对实验人员,实验环境要求不高,而且具有更高的准确度;建议日常生产试验中采用直接进样法测定尿素溶液中的金属离子。The control of metal ions(calcium,iron,copper,zinc,chromium,nickel,magnesium,sodium,potassium and aluminum)in vehicle urea aqueous solution is to avoid poisoning the catalyst of SCR system and affecting the conversion efficiency of nitrogen oxide reduction in SCR system.Its content should also be strictly controlled[1].In order to detect the content of metal ions in vehicle urea aqueous solution more conveniently and quickly,this experiment compares the ashing method and direct injection method on the basis of the national standard GB 29518-2013 diesel engine NOx reductant urea aqueous solution(AUS 32).Through the analysis and comparison of the detection limit,accuracy and precision of direct injection method and ashing method,the results show that the concentration of all elements except Zn measured by ashing method is more than 3 times its corresponding detection limit,and the concentration of Al,Zn,Na,K in direct injection method is less than 3 times the detection limit,indicating that the data measured by ashing method is more true and effective than that measured by direct injection method;Through the standard addition recovery experiment,the results show that the standard addition recovery rate of the direct injection method is higher than that of the ashing method,indicating that the direct injection method has higher accuracy;By calculating the RSD,the results show that the RSD of direct injection method and ashing method are close,indicating that the precision of these two methods is relatively close.Two methods are considered comprehensively:the pretreatment process of ashing method is complex,the consumption of quartz crucible is huge,the cost is high,and the requirements for experimental personnel and experimental environment are very high,but the measured results are more real and effective;The direct injection method is convenient,fast,cost-effective,and has lower requirements for experimental personnel and experimental environment,and has higher accuracy;It is suggested that direct injection method

关 键 词：尿素水溶液 灰化法 直接进样法 回收率 金属离子 

分 类 号：TQ[化学工程]