Synthesis of hierarchical HZSM-5 utilizing natural cellulose as templates for promoted production of aromatic hydrocarbons in the catalytic pyrolysis of biomass

Abstract

Templating agents were created by utilizing several methods to handle natural cellulose (bagasse), and they were successfully used to treat HZSM-5 to introduce extra mesopores. In addition, the hierarchical HZSM-5 was employed in the catalytic pyrolysis of biomass to produce hydrocarbon fuels. The hydroxyl content in the templating agent could be promoted via hydrothermal and ultrasound-assisted treatment, improving their performance as templates to produce mesopores. The cellulose content in the templating agents was effectively boosted via hydrothermal-assisted treatment, whereas their relative crystallinity was improved by ultrasound assistance. The formation of mesopores was promoted with the increased cellulose content in the templating agents, and the catalytic performance in upgrading pyrolysis gas for aromatic hydrocarbons could be significantly improved. Higher relative crystallinity was advantageous for enhancing the stability of the templating agent in the catalyst synthesis system, and the formation of pore structures of the catalyst was promoted. Among all catalysts synthesized, catalysts synthesized by hydrothermal-assisted treatment (Cat-H(X)) presented the highest specific surface area and average pore size of 397.60 m2/g and 4.53 nm, which were about 1.41 and 1.98 times of commercial HZSM-5 (H-Z). The highest yield of BTX obtained with Cat-H(X) was 8.7 wt%, 1.81 times that obtained with H-Z.