Study on Reaction Sites of Active Structures in Coal Based on the ReaxFF Reactive Force Field

To study the reaction paths and reaction mechanisms of the active structures in coal during the oxidation process, the oxygen-free pyrolysis and oxygen-containing combustion were simulated for nine active structures in coal based on the ReaxFF MD method. A separate simulation analysis of the active structure yielded that O₂ inhibited the reaction of H1. As the branched chain grows, the reaction paths of C2 and Q2 follow the direction of the reaction of carboxyl and aldehyde groups to CO₂ and CO. Considering the reaction rates and reaction process products of A1, B1, and B3 structures, it is obtained that O₂ has the greatest contribution to the decomposition reaction of aliphatic hydrocarbon structures. This is due to the strong electron-absorbing property of O₂ that attracts H radicals to generate HO₂, which in turn affects the reaction path of the active structure. Tracing the reaction process reveals that OH and oxygen-containing radicals under oxygen-free conditions greatly influence the active structural reaction.