摘要
采用常规水热法合成了SAPO-11,ZSM-22,ZSM-23,β分子筛,并负载Pt制备了Pt/SAPO-11,Pt/ZSM-22,Pt/ZSM-23,Pt/β加氢催化剂;采用XRD、SEM、N2吸附-脱附、NH3-TPD和吡啶吸附FTIR表征了4种催化剂的结构和酸性;以正十四烷为模型化合物,采用固定床反应器研究了4种催化剂对正十四烷加氢异构反应的催化性能。实验结果表明,正十四烷加氢异构反应遵循孔口-锁钥机理和β断裂机理,催化剂的活性和选择性主要取决于催化剂的结构、酸量、酸强度及其分布,不同催化剂上正十四烷加氢异构反应活性按下列顺序递减:Pt/β>Pt/ZSM-23>Pt/ZSM-22>Pt/SAPO-11;较弱的酸性和较小的孔径更有利于正构烷烃的加氢异构化反应,减少了二次裂化反应。
SAPO-11, ZSM-22, ZSM-23 and β zeolites were synthesized via the conventional hydrothermal method, and then the Pt/SAPO-11, Pt/ZSM-22, Pt/ZSM-23 and Pt/β catalysts were prepared by supporting Pt on the zeolites separately. The four catalysts were characterized by means of XRD, SEM, N2 adsorption-desorption, NH3-TPD and Py-FTIR. The hydroisomerization of n-tetradecane over the catalysts was investigated in a fixed bed reactor. The results indicated that the hydroisomerization accorded with key-lock mechanism and β-cracking mechanism, and the activity of the catalysts mainly depended on their structure, acidity, acid intensity and acid distribution. And the activity decreased in order of Pt/β 〉 Pt/ZSM-23 〉 Pt/ZSM-22 〉 Pt/SAPO-11. Small pore size and low acidity were beneficial to both the hydroisomerization of n-tetradecane and the reduction of the excessive cracking.
出处
《石油化工》
CAS
CSCD
北大核心
2015年第4期429-435,共7页
Petrochemical Technology
基金
中国石油天然气集团公司资助项目(2012A-2203)
