柴油机SCR催化器出口NOx转化效率分布特性研究

Research on distribution characteristics of NOx conversion efficiency of a diesel engine SCR catalyst

中文关键词: 柴油机  选择性催化还原  氮氧化物  转化效率  均匀性

英文关键词: diesel engines  selective catalytic reduction  nitrogen oxide  conversion efficiency  uniformity

中文摘要:

      对柴油机选择性催化还原（SCR）系统的研究，主要集中在催化器出口测量系统的整体氮氧化物（NOx）转化效率。为了进一步提高系统的效率，在柴油机试验台架上，调整不同的排气工况及尿素喷射参数，研究了SCR催化器出口截面的NOx转化效率分布特性，结论表明：催化器出口截面的NOx转化效率分布呈现中心高而边缘低的规律，随着排气流量的增加，NOx转化效率降低，在排气流量较大时，由于弯管对排气流场的作用，NOx转化效率的高效区偏向一侧；提高氨氮比可以提高NOx转化效率，当排气温度为250和350℃时，氨氮比为1.0时就可以达到比较高的效率，进一步提高氨氮比NOx转化效率的增幅不明显；当排气温度为450℃时，提高氨氮比对NOx转化效率的增加比较有利。

英文摘要:

      Experimental investigation of the distribution characteristics of NOx conversion efficiency on the exit cross-section of SCR was presented. This experiment has implemented under various exhaust gas temperature, flow rate and urea injection conditions on a engine test bench. The experiment result shows that the distribution of NOx conversion efficiency of the SCR at the exit cross-section is uniform with a distribution of higher at the center. The higher flow rate, the NOx conversion efficiency is lower. Because the effect of elbow pipe on exhaust gas flow, the efficient zone of the NOx conversion efficiency biased. Increasing ANR can improve NOx conversion efficiency. When the exhaust gas temperature is 250 and 350 ℃, the ANR is 1.0, the higher efficiency can be achieved.