多级孔Zn-La/HZSM-5制备及在甲醇芳构化中的应用

Preparation of Hierarchical Porous Zn-La/HZSM-5 Zeolite and Its Application in Methanol Aromatization

采用NaOH溶液对ZSM-5分子筛进行碱处理,制备了多级孔径ZSM-5分子筛。采用浸渍法制备了多级孔Zn-La/HZSM-5分子筛,并采用XRD、BET、SEM和NH3-TPD等方法进行了表征,在固定床反应器中进行甲醇芳构化反应。结果表明,经过碱处理,ZSM-5分子筛的平均孔径、孔容和比表面积增大,孔径呈微孔和介孔多级孔分布。Zn和La的负载量均为0.5%时,Zn-La/ZSM-5分子筛具有较好的芳构化活性。在反应温度475℃、反应压力0.6MPa、空速(LHSV)0.8h-1条件下,芳烃(苯、甲苯和二甲苯)的收率可达32.3%。

The alkaline treatment of ZSM-5 zeolite with NaOH solution, received the hierarchical porous ZSM-5 zeolite, Zn and La by co-impregnation method of loading in the alkali treatment of the modified ZSM-5 zeolite, the ZSM-5 molecular sieves were characterized by XRD, BET,SEM and NH3-TPD. The reaction of methanol aromatization was investigated in a fixed bed reactor. The results show that after alkali treatment modified ZSM-5 zeolite had a pore size increased and the acidity distribution was changed; Zn-La/HZSM-5 zeolite had the better catalytic, Zn and La with the load capacity of each of 0.5%, the reaction temperature was 475 ℃, the reaction pressure was 0. 6 MPa, LHSV was 0. 8 h-1, the yield of aromatic hydrocarbons （benzene, toluene and xylene） up to 32.3%.