Synthesis of ZSM-22/SAPO-11 composite molecular sieve-based catalysts with small crystallites and superior n-alkane hydroisomerization performance  

作　　者：Xue-Man Wang Cheng-Long Wen Yu Fan 

机构地区：[1]State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing,102249,China [2]Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology,Advanced Catalysis and Green Manufacturing Collaborative Innovation Center,School of Petrochemical Engineering,Changzhou University,Changzhou,Jiangsu,213164,China

出　　处：《Petroleum Science》2023年第4期2585-2595,共11页石油科学(英文版)

基　　金：The authors gratefully acknowledge the financial support of Science Foundation of China University of Petroleum,Beijing(Grant No.KYJJ2012-03-03).

摘　　要：To improve oil quality,ZSM-22/SAPO-11 composite molecular sieves were synthesized by adding ZSM-22 into a synthetic gel of SAPO-11 for n-decane hydroisomerization.The mass ratios of ZSM-22/(ZSM-22+SAPO-11)in the composite molecular sieves were optimized and the optimal ZSM-22/SAPO-11 composite(ZS-9)was obtained.The electrostatic repulsions between the ZSM-22 precursors and the SAPO-11 crystalline nuclei produced small ZSM-22 and SAPO-11 crystallites in ZS-9,which increased the specific surface area and mesopore volume and thereby exposed more acid sites.In comparison with conventional SAPO-11,ZSM-22 and their mechanical mixture,ZS-9 with smaller crystallites and the optimal medium and strong Brønsted acid centers(MSBAC)content displayed a higher yield of branched C_(10) isomers(81.6%),lower cracking selectivity(11.9%)and excellent stability.The correlation between the i-C_(10) selectivity and the MSBAC density of molecular sieves indicated that the selectivity for branched C_(10) isomers first increased and then decreased with increasing MSBAC density on the molecular sieves,and the maximum selectivity(87.7%)occurred with a density of 9.6×10^(−2)μmol m^(−2).

关 键 词：ZSM-22/SAPO-11 composite molecular SIEVES Medium and strong brønsted acid centers Crystallite size Branched C_(10)isomers 

分 类 号：TE624.9[石油与天然气工程—油气加工工程]