Preparation of Two- and Three-layered Hierarchical Catalysts Using Gel Skeletal Reinforcement and Properties for Catalytic Cracking of Low Density Polyethylene

Abstract

The two-layered and three-layered hierarchical catalysts with micropore-small mesopore-large mesopore (micro-meso-meso) structures were prepared using the gel skeletal reinforcement (GSR) method. A Curie point pyrolyzer method was used to evaluate their properties in the catalytic cracking of low density polyethylene (LDPE) and the effects of their pore structure and zeolite type were investigated. The two-layered catalyst prepared with malic acid, TEOS and β-zeolite achieved conversion of 78 % and was more active than similar Y-zeolite-based catalysts. The three-layered catalyst, in which the two-layered catalyst was dispersed in silica made by the GSR method, maintained the conversion despite lower zeolite content. Evaluation of conversion against the XRD integrated intensity and the number of acid sites of the zeolite as a measure of the relative activity of the catalyst found that the relative activity was higher for the hierarchical structured catalyst than for single zeolite and kaolin-mixed catalysts.