表层富硅USY分子筛的制备及其催化性能研究

针对常规“水热超稳”工艺改性的USY分子筛性质和性能上的不足，将常规“二交二焙”的“水热超稳”工艺与原位硅改性方法结合，制备了表层富硅USY分子筛，并将其用于催化裂化(FCC)催化剂的制备；采用X射线衍射、N₂吸附-脱附、NH₃程序升温脱附、扫描电镜等表征手段对所制分子筛进行了表征，并通过ACE装置评价了所制FCC催化剂的性能。结果表明：表层富硅USY分子筛的结晶度、晶胞参数、比表面积、孔体积、表面酸性、微反活性等性质均明显优于常规USY分子筛；与由常规USY分子筛制备的FCC催化剂相比，重油在由表层富硅USY分子筛制备的FCC催化剂上裂化，其转化率提高3.70百分点，汽油收率和液体产物总收率分别提高了2.31百分点和1.32百分点，说明以表层富硅USY分子筛制备的FCC催化剂具有优良的催化性能。

PREPARATION AND PERFORMANCE OF SURFACE SILICA-RICH USY ZEOLITE

In order to improve the properties and catalytic cracking performance of USY zeolite modified by conventional “Hydrothermal hyperstability” process, the conventional “Two-exchange-two-calcination” process was combined with in-situ silica modification method, and the silica-rich USY zeolite was prepared and used for the preparation of FCC catalyst, which was characterized by XRD, N₂ adsorption-desorption, NH₃-TPD, SEM and so on, and the performance of the FCC catalyst was evaluated by ACE unit. The results showed that the crystallinity, crystal lattice parameter, specific surface area, pore volume, surface acidity and micro cracking activity of surface silica-rich USY zeolite were better than those of conventional USY zeolite. Compared with the FCC catalyst made by conventional USY zeolite, the conversion of heavy oil cracked on the FCC catalyst prepared by USY zeolite with silicon-rich surface increased by 3.70 percentage points, and the yield of gasoline and the total yield of liquid products increased by 2.31 percentage points and 1.32 percentage points, respectively, which indicate that the FCC catalyst prepared by USY zeolite with silicon-rich surface layer has excellent catalytic performance.