改性堇青石载体催化剂选择性催化还原NO_x研究

以六次甲基四胺为铝溶胶造孔剂,用正交设计的方法对影响比表面积的4个主要因素范围进行了优选,给出了最佳条件:铝溶胶与六次甲基四胺体积比为3∶1,浸渍次数为6次,焙烧时间为45 min和焙烧温度为400℃,比表面积最大达到75.68 m2/g。考察了改性后载体涂层的冲蚀和抗热冲击性能,负载活性组分后的涂层脱落率均小于5%。并考察以尿素为还原剂,改性前后的载体负载活性组分为催化剂催化还原NO的活性,结果表明,提高比表面积,空速在24000 h-1下转化率仍能大于30%,催化剂起活温度降低到150℃,是提高大空速下催化剂活性和拓宽选择催化还原NOx温度窗口的一种方法。

Selective catalytic reduction of NOx with urea on catalyst of modificated corderite

In this paper,the four main factors which influence the specific surface area are optimized by orthogonal design method.The optimal conditions were using the hexamethylenetetramine as the hole-making agents of aluminum sol,with the volume ratio of alumina sol to hexamethylenetetramine 3 ∶1,at 400 ℃,with 45 min of calcining,and 6 times of impregnation,and the surface area is 75.68 m2/g.The erosion and thermal shock of coating is tested,the result indicated that the abscission rate of coating which load active agents is less than 5%.Using urea as reducing agent,the active agents which loaded on carrier before and after modification deoxidize NO.It indicates that the specific surface area has been enlarged,the conversion is more than 30% at air speed of 24 000 h-1 and the active temperature decreases to 150 ℃.So it is a method to improve the catalytic activity under the large air speed and wide the temperature range in selective catalytic reduction of NOx.