The role of constraint index in catalytic upgrading of lignin bio-oil

Irwan Kurnia, Virdi Chaerusani, Abuliti Abudula, Guoqing Guan
https://doi.org/10.1063/5.0193666

Abstract

One of the classical thermochemical processes for converting lignin to bio-oil is pyrolysis. However, its properties does not meet the requirement due to high amount of oxygenated aromatic content, viscosity, and instability. Thus, it cannot be used directly as fuel and must be refined to increase its quality before to use. In this study, five types of high aluminum zeolites with a wide range channel structure eight-, ten-, and twelve-membered ring were performed. As the results show the channel structure, pore sizes and constrain index of zeolite had significantly affect the deoxygenation process. The constraint index (CI) of zeolites plays an important in the catalytic upgrading process that related to the steric hindrance effect of a zeolite. A zeolite with a high CI (H-ZSM-5) produced a high yield of aromatic hydrocarbons. In the meanwhile, H-Mordenite, H-Beta, and H-USY with a lower CI and large pore supplied more empty space to increase coking, leading to the rapid deactivation of zeolite.

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