不同金属改性对ZSM-5分子筛催化正戊烷和甲醇共芳构化反应性能的影响

EFFECT OF MODIFIED ZSM-5 ZEOLITE WITH DIFFERENT METALS ON n-PENTANE AND METHANOL CO-AROMATIZATION

通过浸渍法对ZSM-5分子筛进行改性,得到不同金属、不同负载量改性的分子筛,采用XRD和Py-IR方法对催化剂进行表征。在固定床微型反应装置上,系统探究了不同金属改性对ZSM-5分子筛催化正戊烷和甲醇共芳构化反应性能的影响。结果表明:Zn,Ag,Ni,Cu改性ZSM-5分子筛均能提高共芳构化反应的芳烃选择性,Ni、Ag改性ZSM-5分子筛表现出更优的芳构化效果,在最优金属负载量下,共芳构化反应中正戊烷和甲醇转化率保持在100%,芳烃选择性高达37.69%;Zn,Ag,Ni,Cu改性ZSM-5分子筛均有新的L酸位形成,B酸量减少,L酸量增加,促进了脱氢反应,反应过程中有更多的烯烃中间体转化为芳烃,提高了芳烃选择性;在不同金属改性ZSM-5分子筛作用下,产物芳烃组成中有不同组分含量的提高。

ZSM-5 molecular sieve were modified with different metals by impregnation method to obtain zeolite catalysts with different metals loads.The catalysts were characterized by XRD,Py-IR techniques.The aromatization performance of the samples in n - pentane and methanol co-aromatization was investigated in a fixed-bed micro-reactor.The results showed that Zn,Ag,Ni,and Cu, modification improved the aromatic selectivity,among which the Ni and Ag modified catalysts showed the better aromatization effects. With the optimal metal load,the conversion rates of n -pentane and methanol were both 100%;the aromatic selectivity was up to37.69%. The catalysts modified with Zn,Ag,Ni,and Cu showed the formation of new L acid,decrease of B acid and increase of L acid,which promoted the dehydrogenation reaction,forming more aromatics from olefin intermediates and improving the aromatic selectivity.The content of different aromatic components in the products increased with the modification of different metals.