金属氧化物和硅沉积改性 ZnO/SiO2/ZSM-5的甲醇择形芳构化反应催化研究

Study of methanol shape-selective aromatization over ZnO/SiO2/ZSM-5 modified with mental oxide and silicon deposition

  • 摘要: 采用真空浸渍法对ZSM-5分子筛进行硅沉积和负载金属修饰,制备了复合改性的ZnO/SiO2/ZSM-5催化剂,并将它应用于甲醇择形芳构化反应中。采用XRD、BET、NH3-TPD、SEM、TEM等方法对制备的催化剂进行了物化表征。考察硅沉积次数和ZnO负载量对甲醇芳构化反应(MTA)中对二甲苯(PX)的选择性和收率的影响。结果表明,两次硅沉积改性并负载2.0%金属ZnO的ZSM-5分子筛具有较高的PX收率,在优化的反应温度420 ℃、反应压力0.2 MPa、甲醇空速WHSV为1.25 h-1下,PX收率在28%以上。

     

    Abstract: ZnO/SiO2/ZSM-5 zeolites were prepared from ZSM-5 by vacuum metal impregnation of metallic oxides and silicon deposition. The resulted zeolite were characterized by XRD, BET, NH3-TPD, SEM and TEM. Furthermore, the influence of silicon deposition time and the content of impregnated ZnO to the selectivity and yield of p-xylene (PX) on the reaction of aromatization of methanol was investigated. The results indicated that by twice silicon deposition and 2.0% ZnO, the modified ZSM-5 had the highest PX selectivity. The yield of PX could reach up to 28% at 420 ℃, 0.2 MPa and 1.25 h-1 of methanol WHSV.

     

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