FCC催化剂中两组分裂化重油较大分子的作用分析

SELECTIVITY SYNERGISM OF FCC CATALYSTS IN CRACKING BIG MOLECULES OF HEAVY OIL FEEDS

采用较简单集总动力学网络对FCC催化剂中两组分在“一次”裂化较大分子中的作用进行了分析.结果表明,沸石晶粒外表面的形状因素对沸石外比表面积有较大影响.含有一定二次孔的较小晶柱沸石,不仅可以有相当大的外表面积(60～100m^2/g),有利于提高其重油FCC性能,而且扩散性和传递性较好,也有利于提高其中等分于的FCC性能。因而有更好的FCC性能.根据特定反应系统的性能确定出与重油FCC体系相适应的沸石外比表面积与基质比表面积比例,能使重油较大分子的一次裂化反应在两组分上有较好的分配比例,可提高重油FCC过程的选择性.

An analysis by using lumped overall kinetics network shows that the curvature factor of Y-type zeolite cristalline grain may have an important influence on the exterior surface area of Y-type zeolite crystallites. Small zeolite crystallites containing a certain amount of secondary pores can have better heavy oil FCC performance, as they can have a substantial amount of exterior surface area (60~100m2/g) and better transport properties. An optimum zeolite/matrice ratio according to the characteristics of a special reaction system can give better heavy oil FCC selectivity so as to get better selectivity synergism for the precracking of large molecules in heavy oil feeds.