FCC汽油馏分在水热处理Zn/HZSM-5催化剂上的芳构化反应

制备了300 ℃、350 ℃、400 ℃和500 ℃不同水热处理温度下的Zn/HZSM-5催化剂，并用于FCC汽油馏分的芳构化反应。考察了水热处理温度对芳构化反应性能的影响，并与吡啶吸附红外光谱(FT-IR)相关联，研究了水热处理温度对催化剂表面酸性的影响。结果表明，水热处理Zn/HZSM-5的芳构化活性稳定性得以改善, 与未经水热处理的催化剂相比，400 ℃水热处理的Zn(2%)/HZSM-5催化剂芳构化反应36 h时，芳烃质量分数仍高达74.25%。随着水热处理温度的升高， B酸酸中心数在300～400 ℃变化不大，500 ℃显著减少，L酸酸中心数升高，400 ℃达到最大值后呈降低趋势，烯烃转化率、烷烃转化率和产品芳烃含量升高，水热处理400 ℃时均达到最大值，分别为83.62%、95.44%和92.23%，表明此时B酸中心和L酸中心比例协调性最佳。

Aromatization of FCC gasoline fraction over hydrothermally treated Zn/HZSM-5 catalyst

Zn/HZSM-5 catalysts for aromatization of FCC gasoline fraction were prepared by hydrothermal treatment at different temperature (from 300 ℃ to 500 ℃). Influence of hydrothermal treatment temperature on aromatization behavior of the catalyst was investigated. Influence of hydrothermal treatment temperature on surface acidity of the catalyst was studied using FT-IR. The results showed that stability of the aromatization activity was enhanced by hydrothermal treatment. For Zn (2%)/HZSM-5 catalyst treated at 400 ℃, aromatics mass fraction in the product of 74.25% was attainable after reacting for 36 h. The quantity of Brnsted acid sites changed little in 300～400 ℃, but decreased significantly at 500 ℃. The quantity of Lewis acid sites increased with treatment temperature, but declined after 400 ℃. Optimum amomatization results were attained over the catalyst treated at 400 ℃, with olefins conversion, alkenes conversion and mass fraction of aromatics in the product of 83.6%, 95.44% and 92.23%, respectively, which means that best coordination between of Brnsted and Lewis acid sites was attained at this treatment temperature.