Abstract:

Y zeolite was modified with Zr by equal volume impregnation method. The effects of different amounts of Zr on the structure of modified Y zeolite, the physicochemical properties of the catalyst and the performance of hydrocracking reaction were investigated systematically. The modified Y zeolite and catalyst were characterized by X-ray diffraction (XRD), NH₃ temperature programmed desorption (NH₃-TPD), H₂ temperature programmed reduction (H₂-TPR) and transmission electron microscopy (TEM). The results show that Zr modification decreased the amount of acid sites of Y zeolite, and the trend became larger with an increase of Zr content. Moreover, Zr modification availably weakened the relation of metal species and support in the catalyst with Y zeolite, and improved the dispersion of W species on the catalyst surface. The hydrocracking reaction results suggested that VGO conversion over the catalyst with Y zeolite modified with Zr decreased compared with that with Y zeolite, and middle distillates increased about 20%(mass), as well as VGO conversion gradually decreased and the middle distillates slightly increased as the Zr content increased.

Key words: catalyst, zeolite, support, hydrocracking, Zr modification, middle distillates

摘要：

采用等体积浸渍法对Y分子筛进行了Zr修饰改性，系统考察了不同用量Zr对改性Y分子筛的结构、催化剂的理化性质和加氢裂化反应性能的影响规律。通过XRD、NH₃-TPD、H₂-TPR和TEM等方法对改性分子筛和催化剂进行表征分析。结果表明：Zr改性降低了Y分子筛的酸量，随着改性Zr用量的增加，这种变化趋势不断增大。同时，Zr改性有效地削弱了分子筛催化剂中金属活性组分与载体间的作用，提高了W物种在催化剂表面的分散程度。加氢裂化反应结果表明：与Y分子筛催化剂相比，Zr改性Y分子筛催化剂的减压馏分油(VGO)转化率降低，中间馏分油选择性提高约20%，随着改性Zr用量的增加，VGO的转化率不断降低，中间馏分油选择性略有增加。

关键词: 催化剂, 分子筛, 载体, 加氢裂化, Zr改性, 中间馏分油