蒸汽相转化法原位诱导沸石化制备Y-ZSM-5双沸石复合物  

Y-ZSM-5 Zeolite-Zeolite Composites Prepared by the Steam-Assisted Conversion Method

作　　者：高禾鑫 李鹏[1] 杜艳泽[1,2] 郑家军[1] 潘梦[1] 刘芝平[1] 李瑞丰[1] 

机构地区：[1]太原理工大学能源化工与催化研究中心,太原030024 [2]抚顺石油化工研究院,抚顺113001

出　　处：《无机化学学报》2017年第7期1249-1256,共8页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金委-中石化联合基金重点支持项目(No.U1463209);国家自然科学基金(No.21371129;21376157);中国石油化工股份有限公司项目(No.116050)资助

摘　　要：针对Y型沸石在ZSM-5沸石干胶制备及晶化过程中易于溶解、坍塌的问题,采用葡萄糖在水热处理条件下对Y沸石进行包膜处理,提高了Y沸石在高温、高碱度环境中的稳定性,并采用蒸汽相转化法制备了同时含有Y和ZSM-5的双沸石复合物。对影响沸石复合物形成的因素如Y沸石表面碳包膜改性、凝胶碱度、晶化时间等进行了详细讨论。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅立叶变换红外(FT-IR)、N2吸附-脱附,能谱(EDS)以及NH3-TPD等手段对制备的材料进行了表征。结果表明通过蒸汽相转化法能获得Y和ZSM-5两相共存的双沸石复合物,产物中的ZSM-5沸石相前驱体随蒸汽处理时间的延长逐渐从蠕虫状无定型向纳米多晶ZSM-5沸石转变,纳米多晶聚集体与Y型沸石晶粒之间紧密相连,相互包埋。在异丙苯催化裂化反应中,合成的沸石复合物的活性和稳定性介于Y和ZSM-5之间,优于对应的机械混合物。Y zeolite crystals is liable to be depolymerized because of the attack of alkali species on its frameworks, which even causes the framework collapse. During the synthesis of the zeolite-zeolite composite composed of FAU and MFI, the dissolution of Y zeolite crystals will change the composition of gel precursors yielding MFI zeolite phase. In present work, Y zeolite crystals, which was mixed with the gel precursors of ZSM-5, were modified with carbon membrane yielded from glucose by hydrothermally treatment at 180 ~C for 3 h. Zeolite-zeolite composite consisting of FAU and MFI was therefore synthesized by the steam-assisted conversion （SAC） method. The factors affecting the formation of the composite were investigated in details. The as-synthesized samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） spectroscopy, N2 adsorption-desorption, energy dispersive X-ray spectroscopy （EDS）, and NH3-TPD. The results showed that the precursors yielding ZSM-5 zeolite gradually transfered from a worm-like morphology to nano- sized MFI zeolite crystals. As compared with the pure Y, ZSM-5 or the corresponding physical mixture of Y and ZSM-5 with the similar composition and ratio, the activity and catalytic life of the zeolite composite investigated during the isopropylbenzene catalytic crack fall between those of the single Y and ZSM-5 catalysts, while significantly better than those of the corresponding physical mixture.

关 键 词：沸石 复合物 蒸汽相转化法 催化裂化 

分 类 号：TQ174[化学工程—陶瓷工业]