酸碱处理对ZSM-5分子筛物化性质和反应性能的影响  

Effects of acid-alkali treatment on properties and reactivity of ZSM-5 catalyst

作　　者：吕江江[1] 黄星亮[1] 赵蕾蕾[1] 孙仁山[1] 胡龙旺 龚艳[1] 

机构地区：[1]中国石油大学(北京)化学工程学院,北京102249

出　　处：《燃料化学学报》2016年第6期732-737,共6页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(51261012);昆明理工大学分析测试基金(20140292)资助~~

摘　　要：考察了碱处理、先碱后两步酸处理对HZSM-5分子筛物化性质以及苯与甲醇烷基化反应性能的影响。结果表明,碱处理在脱除分子筛中非骨架硅的同时,提高了晶孔的利用率,也中和了分子筛的强酸中心,使催化剂活化甲醇的能力减弱,苯与甲醇反应活性降低;先碱后两步酸处理既脱除了分子筛中的非骨架铝,也恢复了一部分强酸中心,提高了苯与甲醇的反应活性。进一步考察了先碱后两步酸处理中不同碱浓度的影响,结果表明,适宜浓度的碱处理后再两步酸处理,一方面,能脱除分子筛的非骨架硅铝物种,使分子筛的颗粒粒径更加均匀;另一方面,分子筛的强酸中心有所减少,降低了催化剂的积炭失活速率,苯转化率提高15%以上。The effects of alkali-treatment and alkali-acid-treatment of ZSM-5 on the catalytic properties and catalytic performance of benzene alkylation with methanol were studied.The results showed that alkali treatment of ZSM-5 can remove the extra-framework Si species to enhance the diffusivity.However,it can also neutralize the strong acid sites of ZSM-5 and weaken the activation of methanol,reducing the reactivity of benzene alkylation with methanol.The twice acid treatment of alkali-treated ZSM-5 improve the catalytic performance because it can not only remove the extra-framework Al species,but also restore a part of strong acid sites neutralized in the process of alkali-treatment.Further research on the effects of alkalinity showed that the extraframework Al species and Si species can be removed and a moderate particle size can be obtained after treatment of ZSM-5 with a moderate concentration of alkali.Moreover,the carbon deposition rate has been slowed down due to a decrease of strong acid sites.Therefore,the conversion of benzene can be improved by more than 15%.

关 键 词：碱处理 强酸中心 非骨架硅铝物种 苯-甲醇烷基化 

分 类 号：TE624.9[石油与天然气工程—油气加工工程]