不同结构的芳烃对加氢裂化催化剂积炭的影响

在高压连续流动微型反应器上采用催速老化技术考察了不同结构的芳烃在加氢裂化催化剂上积炭行为，并用热分析、傅立叶变换红外和物理吸附仪等手段对积炭催化剂的积炭类型、酸强度分布和孔结构的变化进行了研究。结果发现：单环芳烃中，随着取代基的碳链长度、数目及不饱和度的增加，催化剂更容易积炭。稠环芳烃的环数越多，反应生成的总积炭和假石墨型积炭越多。积炭越多的催化剂，比表面积降低越多。积炭主要沉积在催化剂的小孔内或堵塞小孔孔口，有些积炭在催化剂表面形成机械孔。积炭后，催化剂上不同强度的酸数目均较新鲜催化剂降低，尤其是萘和菲，使强酸严重削弱。

EFFECT OF AROMATICS WITH VARIOUS STRUCTURES ON COKE DEPOSITED ON HYDROCRACKING CATALYST

The coke deposition of various aromatics on hydrocracking catalyst has been obtained using accelerated aging experiment. Acid strength distribution, pore structure and coke type of catalyst were measured by FT-IR,physical absorpmeter and thermal analysis. The results showed that for single ring aromatics, involving benzene, toluene, para-xylene, ethylbenzene and styrene, the characters of substituted-groups, including carbon chain length, number and saturation, could affect the amount of coke and pore character. Longer carbon chain, larger number and less saturation could result in more coke deposition on catalyst. For different rings aromatics without any substituted-group, involving benzene, naphthalene and phenanthrene, the amount of both general coke and the pseudo-graphite structure coke increase with the increase of aromatic rings, but the total amount of acid decreases gradually, especially for strong acid. For all aromatics, the specific surface area of deactivated catalyst decreases with the increase of the coke. The coke impenetrates in all pores and mainly deposited in small pore of catalyst, while some of coke could form mechanical pore on catalyst surface.