焙烧温度对HZSM-5催化剂催化甲醇制汽油反应性能的影响

EFFECT OF CALCINATION TEMPERATURE ON PERFORMANCE OF HZSM-5 CATALYSTS IN METHANOL TO GASOLINE

以NaZSM-5分子筛为原料,采用离子交换法制备HZSM-5催化剂,通过X射线衍射、FT-IR、低温N_2吸附-脱附等手段对催化剂的结构和性质进行表征,在固定床微反装置上,考察焙烧温度对催化剂催化甲醇制汽油反应性能的影响。结果表明:焙烧温度对HZSM-5催化剂的催化性能影响显著,在焙烧温度为550℃时制备HZSM-5催化剂的比表面积高达351.1m^2/g,孔体积和孔径分别为0.311cm^3/g和3.20nm,甲醇转化率、汽油收率和芳烃含量最优;随着焙烧温度的升高,HZSM-5催化剂内微孔结构坍塌和部分孔道堵塞,表面总酸量急剧减少,造成催化甲醇反应活性降低。

Using NaZSM-5 zeolite as raw material, the HZSM-5 catalysts were prepared by ion exchange method and characterized by XRD, FT-IR, and N2 adsorption-desorption. The effect of calci- nation temperature on the catalytic performance for methanol to gasoline （MTG） reaction was investiga- ted in a micro-fixed bed reactor. The results show that the calcination temperature has an evident influ- ence on the catalytic performance of the HZSM-5 catalysts. With increasing calcination temperature, the catalyst activity decreases as part of the channel in the HZSM-5 catalysts are blocked and the acid sites rapidly reduced. The HZSM-5 catalysts calcined at 550℃ exhibit a higher specific surface area of 351.1 m^2/g, and higher pore volume of 0. 311 cm^3/g and pore diameter of 3.20 nm, leading to an optimal methanol conversion, gasoline yield and aromatics selectivity.