全氢菲在分子筛催化剂上环烷环开环反应的研究

在小型固定流化床(FFB)装置上考察了Y与ZSM-5分子筛催化剂以及Y分子筛催化剂上温度、剂油比对全氢菲裂化环烷环开环反应的影响。结果表明,全氢菲在分子筛催化剂上通过环烷环开环反应生成环己烷、十氢萘等单环或双环环烷烃;单环或双环环烷烃进一步侧链断裂生成2-甲基戊烷、甲基己烷等异构烷烃等,异构化生成二甲基环戊烷、甲乙基环戊烷等烷基环戊烷,氢转移生成苯、甲苯、二甲苯等烷基苯,进行深度氢转移反应生成萘、烷基萘等双环芳烃;另外,全氢菲也会通过脱氢缩合生成菲、芘等三环以上芳烃甚至焦炭等。由于扩散和吸附性能的影响,其裂化开环反应的选择性在Y分子筛催化剂上比在ZSM-5分子筛催化剂上高。因此,全氢菲环烷环开环与脱氢缩合反应的相对比例(s(NRO)/s(DHC))在Y分子筛催化剂上较高;在Y分子筛催化剂上,温度为475~550 ℃、剂油比为3.0~9.0,反应温度升高或者剂油比增加,双分子氢转移以及脱氢缩合反应增强,导致环烷环开环反应产物选择性降低。

Naphthenic ring opening of perhydrophenanthrene over zeolite catalysts

Experiments of perhydrophenanthrene cracking over zeolite catalysts were conducted in a small fixed fluidized bed(FFB) unit.Effects of Y and ZSM-5 zeolite catalysts,temperature and catalyst/oil ratio on naphthenic ring opening reactions of perhydrophenanthrene were examined.The results show that products from naphthenic ring opening reactions of perhydrophenanthrene over zeolite catalysts are monocyclic or dicyclic cycloparaffin(cyclohexane,decalin),which is further converted into isoparaffin(2-methylpenptane,methyl hexane) by side chain breaking,or into monocyclic aromatics(benzene,C1~4 alkyl benzene) by hydrogen transfer,or into dicyclic aromatics(tetrahydronaphthalene,naphthalene,alkyl naphthalene) by deep hydrogen transfer.Products from dehydrogenation condensation reactions of perhydrophenanthrene are polycyclic aromatics with more than 3 rings(phenanthrenes,pyrenes) and coke.Due to the influence of naphthenic diffusion and adsorption on catalysts,selectivity of the naphthenic ring opening reaction is higher over Y catalyst than that over ZSM-5catalyst.The relative ratio of naphthenic ring opening reactions to dehydrogenation condensation reactions,abbreviated as s(NRO) /s(DHC),is higher over Y catalyst than that over ZSM-5 catalyst.At the weight hourly space velocity of 10 h-1,temperature of 475~550 ℃,catalyst/oil mass ratio of 3.0~9.0,reactions of bimolecular hydrogen transfer and dehydrogenation condensation became stronger,and selectivity of the products from naphthenic ring opening reactions decreases with the rising of temperature or catalyst/oil ratio over Y catalyst.