【摘要】 采用水热、草酸脱铝及表面活性剂存在下的水热晶化相结合的组合法对Y型分子筛进行了改性,考察了表面活性剂十六烷基三甲基溴化铵(CTAB)存在下的CTAB加入量对Y型分子筛相对结晶度(Xc)、晶胞常数(a0)、硅铝比、比表面积、孔结构及加氢裂化性能的影响,并利用NH3-TPD对改性Y型分子筛进行了酸性表征。结果表明,少量的CTAB就可以使Y型分子筛的相对结晶度从37.9%提高到68.3%,硅铝比从7.72增大到9.32,a0从2.453 4 nm减小到2.448 5 nm,介孔的孔体积从0.157 mL/g提高到0.180 mL/g以上,且总酸酸量降低。VGO的加氢裂化反应结果表明,CTAB存在下改性Y型分子筛的加氢裂化活性和中间馏分油收率比工业催化剂分别高2.42%和4.20%。更多还原

【Abstract】 Molecular sieve Y was modified by a combination of hydrothermal treatment,dealuminization with oxalic acid,and hydrothermal crystallization in the presence of the surfactant cetyl trimethyl ammonium bromide(CTAB).The effects of CTAB amount used on the crystallinity,unit cell constant,SiO2/Al2O3 ratio,surface area and pore structure of the modified molecular sieve Y were investigated.NH3-TPD was employed to characterize the acidity.The results showed that after modification,the crystallinity and SiO2/Al2O3 ratio of the molecular sieve Y increase from 37.9% and 7.72 to 68.3% and 9.32,respectively.The unit cell constant a0 decreases from 2.453 4 nm to 2.448 5 nm.The pore volume of mesopores increases from 0.157 mL/g to over 0.180 mL/g.The total acid sites are reduced after the modification.Hydrocracking of vacuum gas oil(VGO) over the modified molecular sieve revealed that the conversion and yield of middle distillates is improved by 2.42% and 4.20%,respectively,compared with that over the industrial catalyst.更多还原