四氢萘在分子筛催化剂上环烷环开环反应的研究

摘要

Experiments of tetrahydronaphthalene cracking over Y and ZSM-5 zeolite catalysts under certain reaction temperature and catalyst/oil (C/O) ratio were conducted on a fixed fluidized bed (FFB) unit in laboratory. Test results show that the products of tetrahydronaphthalene cracking over these two zeolite catalysts by naphthenic ring opening reactions are non-aromatics (propane,propylene,butane,butylenes, methylpenptane, cy-clopentane,cyclohexane) and monocyclic aromatics (benzene,C1 ~C4 alkyl benzene). Products of which by dehy-drogenation condensation reactions are polycyclic aromatics ( naphthalene, alkyl naphthalene, phenanthrenes, py-renes and so on) and coke. Among them,the relative ratio of naphthenic ring opening reactions to dehydrogena-tion condensation reactions over Y and ZSM-5 zeolite catalysts is 1. 22 and 0. 95,respectively. Due to the diffusion and adsorption of naphthenic aromatics on these two catalysts are varied,the selectivity to naphthenic ring opening reactions is higher over Y zeolite catalyst than those over ZSM-5 zeolite catalyst. Under the conditions of a WHSV of 10 h-1 ,reaction temperature in the range of 450-550℃ ,C/O mass ratio in the range of 3-9,the reactions of bimolecular hydrogen transfer and dehydrogenation condensation over Y zeolite catalyst enhance with the increase of reaction temperature and/or C/O ratio,as a result,the selectivity to the products from naphthenic ring opening reactions decreases.%在小型固定流化床(FFB)装置中考察了Y与ZSM-5分子筛催化剂以及温度、剂油比对四氢萘裂化环烷环开环的影响.结果表明:四氢萘在分子筛催化剂上通过环烷环开环反应生成丙烷、丙烯、丁烷、丁烯、甲基戊烷和环戊烷、环己烷等非芳烃以及苯、C1～C4烷基取代苯等单环芳烃；并通过脱氢缩合反应生成萘、烷基萘、菲、芘等多环芳烃直至焦炭等；其中环烷环开环与脱氢缩合反应的相对比例在两种分子筛催化剂上分别为1.22、0.95.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；在温度450～550℃、剂油质量比3～9范围内,随着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,从而导致环烷环开环产物选择性降低.