不同硅铝比β沸石的理化性质及烃类催化裂化活性  

Physicochemical Properties and Activities of Hydrocarbon Catalytic Cracking of β-Zeolite with Different Silica-Alumina Ratios

作　　者：李强[1] 窦涛[1] 霍全[1] 徐庆虎[1] 巩雁军[1] 潘惠芳[1] 

机构地区：[1]中国石油大学(北京)化工学院CNPC催化重点实验室,北京102249

出　　处：《物理化学学报》2008年第7期1192-1198,共7页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(973)(2004CB217806);中石油股份公司(050203-01-07)资助

摘　　要：采用润湿态固相转化方法按照投料硅铝摩尔比(n(SiO2)/n(Al2O3))分别为30、60、150、300、500和纯硅时合成了β沸石,化学法和X射线荧光(XRF)测定产物的硅铝比和反应初始凝胶基本一致.利用X射线衍射(XRD)、红外光谱(FT-IR)、扫描电镜(SEM)、氨程序升温脱附(NH3-TPD)和低温N2吸附对系列样品的物相、水热稳定性、晶体形貌、酸性以及表面积和孔体积做了系统的表征.并将该系列样品作为活性组分添加剂,以高岭土为基质分别制备烃类裂化催化剂,对其催化裂化性能进行了评价.结果表明,不同硅铝比β沸石添加到裂化催化剂均可以提高其裂化活性,改善催化剂的抗积炭性能,硅铝比为150的β沸石催化剂在保持较高裂化活性的前提下,汽油收率最高,抗积炭性能也较好,是优选的裂化催化材料.High-crystallized β-zeolites with different silica-alumina molar ratios were successfully synthesized in extremely dense aqueous system using tetraethylammonium hydroxide （TEAOH） as template and solid silica gel as silica source, respectively. The silica-alumina molar ratios in the initial gels were 30, 60, 150, 300, 500, and pure silica, respectively, which were consistent with those in so-prepared samples determined by chemical method and XRF analysis, Subsequently, the physicochemical properties of samples were characterized by X RD, FT-IR, SEM, NH3- TPD, and N2-adsorption analysis. The results showed that the extent of dealumination was changed obviously and the acid content was decreased significantly in the low silica β-zeolite with highest aluminium content after hydrothermal treatment. The high silica or pure silica β-zeolites could not display higher hydrothermal stability partly due to their small grain sizes. After hydrothermal treatment, the medium silica-alumina ratio zeolite beta could remain higher acid amount and showed better hydrothermal stability. The effect of β-zeolites with different n（SiO2）/n（Al2O3） ratios as an active additive on cracking performance has been investigated. It was found that β-zeolite could increase the activity of cracking catalyst and improve the performance of resistance to carbon deposition. As β-zeolite with n（SiO2）/n（Al2O3） molar ratio of 150 was added, the cracking catalyst exhibited the higher cracking gasoline yield and lower carbon deposition.

关 键 词：硅铝比 Β沸石 理化性质 催化裂化 

分 类 号：O643.36[理学—物理化学]