Catalytic upgrading of pyrolysis vapor from rape straw in a vacuum pyrolysis system over La/HZSM-5 with hierarchical structure.

Catalytic upgrading of pyrolysis vapor from rape straw was performed in a vacuum pyrolysis system over La/HZSM-5 with hierarchical structure. When 3M NaCO was used for alkali treatment, the desilication process of HZSM-5 zeolite was highly controllable and the hierarchical porous HZSM-5(Hi-ZSM-5) zeolite was formed. After that, Hi-ZSM-5 was modified by impregnation with lanthanum ion, the acid sites of Lewis increased and the concentrations ratio of Brönsted acid and Lewis acid of the catalyst was improved.