Preparation of composite HZSM-5 catalyst by green template and catalytic the pyrolysis of biomass to produce aromatics

In this study, HZSM-5 was modified by green templates (cellulose, starch and glucose), the mesoporous structure was successfully introduced, and the prepared composite catalyst was used for the catalytic pyrolysis of biomass to prepare aromatics hydrocarbon. It was revealed that the additionally introduced mesopore pore size was closely related to the size of the template molecule. The formation of pore structures with larger pore sizes on the catalyst was facilitated by larger polysaccharide templates (starch and cellulose). The increase in mesopore pore size was promoted by the cellulose and starch templates, while the increase in the number of mesopores was promoted by the glucose template. The pore size of the catalyst has a great influence on selectivity of BTX. Selectivity of BTX with larger carbon numbers (xylene, trimethylbenzene) was improved by the mesoporous structure with larger pore size. Excellent catalytic performance is also shown on template modified catalysts. The maximum yield of BTX was 10.18 wt%, which was about 1.1times higher than HZSM-5. In addition, the decomposition of macromolecular substances in the pyrolysis gas was promoted by the mesoporous structure of the template-modified catalyst, and the formation of coke on the catalyst was prevented.