多产低碳烯烃及柴油用分子筛的设计

目前，催化裂化的原料大多是蜡油和减压渣油的混合油，或全部的常压渣油 .其相对分子量范围很宽，组成十分复杂 .为了分别对待大小不同的分子和不同碳氢比化合物的裂化性能，现代催化裂化催化剂应具有梯度孔结构与梯度酸中心的优化结构配置 .而目前催化裂化的主导分子筛 USY二次孔含量还不能满足原料油日趋变重的需求，并且滞留在分子筛孔 /笼内的非骨架铝限制了其选择性的进一步提高，因此有必要对其结构进一步修饰 .　　本研究在 USY基础上合成新的催化裂化多产低碳烯烃和柴油用分子筛催化剂 .新型 USY基分子筛从晶体结构、孔容及孔…

Optimization of Zeolite for Producing Lighter Olefin and Diesel in FCC Process

A new method to design FCC catalyst for producing lighter olefin and diesel was developed and the USY- based catalyst was synthesized by means of this method. The USY zeolites ultrastablized in the hydrothermal treatment were further modified with tartaric acid in unbuffed system. The crystal structure, surface area and pore distribution,thermal stability and micro- activity for catalytic cracking of modified samples were respectively characterized by XRD, N2- adsorption,DTA and MAT techniques. The result shows that the Si/Al ratios,crystallinities and thermal stabilities of modified USY samples are effectively improved;simultaneously, the crystal cell size and particle size are obviously decreased. The pore system (micro- pore and secondary mesopore) is positively developed and the pore distribution is obviously optimized. The optimization of pore and acid sites results in the preferable production of lighter olefins and diesels in FCC process. This means that FCC reaction on modified USY zeolite leads to deep cracking in micropores and partial cracking in mesopores. Optimization of this modified USY zeolite might result in a novel FCC catalyst.