Study on the mechanism of hydrogen production from bamboo gasification in supercritical water by ReaxFF molecular dynamics simulation

In the context of sustainable development, biomass and clean energy have garnered significant attention. At present, the inefficient utilization of biomass leads to a significant waste of resources. Supercritical water gasification technology not only facilitates the resourceful utilization of biomass but also generates hydrogen. This paper presents a molecular dynamics simulation study on bamboo as the subject for investigation, complemented by experimental validation to ascertain the efficacy of the simulation outcomes. The bamboo model is prepared by mixing Crystalline Cellulose Iβ, (1 → 4)-β-D-xylopyranose, α-L-arabinofuranose-(1 → 3)-β-D-xylopyranose, and two syringyl units connected by a β-O-4 bond in a ratio of 46:13:15:26. The study analyzes the influence of various parameters on the gasification results and elucidates the gasification reaction mechanism of bamboo in supercritical water. The results indicate that at a reaction temperature of 4300 K and a feedstock concentration of 5 wt%, the H₂ yield reaches 85.6 % of the total output. Additionally, the reactive force field molecular dynamics method was used to simulate the SCWG process of bamboo, providing theoretical support for improving gasification efficiency. The simulation results show that bamboo decomposition is accompanied by chain cleavage, ring-opening reactions, and the formation of small molecules. Furthermore, the study explored the formation pathways of carbon dioxide and hydrogen.