Thermal pyrolysis behavior and mechanisms of kraft lignin using methane, H2, and H2O as reactive medium: A ReaxFF molecular dynamics simulation

Z Liang and KJ Li and CH Jiang and WM Zhan and YS Bu and JL Zhang and AN Conejo, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 90, 159-170 (2024).

DOI: 10.1016/j.ijhydene.2024.09.374

Biomass has become an alternative to fossil fuels due to its capacity to provide carbon-neutral energy. However, the conversion of kraft lignin into high-value chemicals remains challenging. Hydrotreatment, utilizing CH4, H2, or H2O, enables the production of high-quality liquid hydrocarbon fuels while enhancing hydrogen utilization. Reactive molecular dynamics was employed to investigate the influence of CH4, H-2, and H2O as reactive medium of kraft lignin at the atomic scale. The three reactive mediums increased the maximum heavy tar yield by 8.34%, 8.07%, and 8.53% respectively, and increased the hydrogen content of pyrolysis products. Steam conditions promote the decomposition of ether bonds, while H-2 and CH4 exhibit stronger inhibitory on the decomposition of carbon hexagonal rings. A crucial role of pentagonal carbon rings as intermediates in the lignin cracking process was found. These findings provide valuable insights for optimizing the pyrolysis conditions of kraft lignin to achieve the desired product yields.

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