Catalytic upgrading of lignocellulosic biomass pyrolysis vapors: Insights into physicochemical changes in ZSM-5

Abstract Catalytic fast pyrolysis of biomass is an effective strategy for the preparation of high value-added liquid fuels or chemicals. Understanding the effects of different biomass materials on the physicochemical property changes of ZSM-5 is important for the design of modified catalysts and targeted regulation of products. In this study, the catalytic upgrading of lignocellulosic biomass over ZSM-5 was investigated. Lignin, cellulose and xylan were used as model compounds of lignocellulosic biomass, and the upgraded products were analyzed online. Several techniques were used to gain a deep understanding of the physiochemical changes in ZSM-5. The results showed that the addition of ZSM-5 contributed to the production of aromatic hydrocarbons and olefins. The crystal structure and morphology of ZSM-5 were not changed, but the total acid, Bronsted and Lewis acid contents decreased. The amount of coke deposited on ZSM-5 follows the order cellulose/ZSM-5 > xylan/ZSM-5 > lignin/ZSM-5. Coke on cellulose/ZSM-5 has the lowest H/C ratio of 0.50. Coke on ZSM-5 will create new micropores and increase the specific surface area of micropores.