Research progress on oil shale pyrolysis mechanisms: secondary reactions and their influencing factors

Oil shale pyrolysis is among the most effective approaches for achieving efficient resource utilization. However, the influence of process parameters on secondary reactions remains poorly understood, thereby limiting conversion efficiency. This review summarizes current insights into oil shale pyrolysis mechanisms and reaction processes based on pyrolysis product characterization and kinetic modeling, with particular emphasis on secondary reactions and the roles of key controlling factors. Given the limitations of conventional experimental methods in elucidating microscopic reaction mechanisms, this review further highlights recent advances in integrating experimental characterization with multiscale molecular simulation approaches. Finally, existing technical challenges and research gaps are critically assessed, and future research directions are proposed. The review provides theoretical and practical guidance for optimizing hydrocarbon generation and advancing in situ oil shale pyrolysis technologies.