La改性HZSM-5分子筛催化剂甲醇转化制汽油反应性能研究

采用浸渍法制备了La改性HZSM-5分子筛催化剂，利用X射线衍射（XRD）、氮气吸附-脱附、氨气程序升温脱附（NH₃-TPD）以及吡啶吸附红外光谱（Py-FTIR）技术对催化剂进行表征，并在固定床微型反应评价装置上，在反应温度350℃，系统压力0.1 MPa，甲醇质量空速4.74 h^-1的条件下，考察La改性HZSM-5分子筛催化剂的甲醇转化制汽油反应性能。结果表明，La改性HZSM-5分子筛催化剂的酸量降低，比表面积和孔容减小。La负载量为4%时，其MTG反应性能最佳，催化剂的寿命和汽油收率分别由改性前的12 h和52.69%增加到16 h和59.28%。此外，随着La负载量的增加，汽油中芳烃含量显著降低，降幅达18%。

Catalytic performance of La-modified HZSM-5 catalysts for methanol to gasoline reaction

La-modified HZSM-5 catalysts were prepared by impregnation method, and characterized by XRD, NH₃-TPD, Py-FTIR and N₂ adsorption/desorption techniques. Their catalytic performance in methanol to gasoline (MTG) reaction was evaluated in a fixed-bed tubular reactor at 350℃ and WHSV of 4.74 h^-1 under ambient pressure. The results show that the introduction of La decreased the amount of acid sites, specific surface area and pore volume of HZSM-5 catalyst. The catalyst with La loading of 4% exhibited the best catalytic performance in MTG reaction, over which the lifetime and gasoline yield increased from 12 h and 52.69% to 16 h and 59.28%, respectively. In addition, the selectivity to aromatics in gasoline decreased markedly by 18% with increasing La content.