Simulation strategies for ReaxFF molecular dynamics in coal pyrolysis applications: A review

Research on pyrolysis mechanisms has attracted significant attention as they can efficiently assist in coal resource utilization. Although experimental techniques have significant advantages in terms of quantitative assays, exploring the detailed chemical mechanisms and complex reaction pathways of pyrolysis requires computational methods. Therefore, the emergence of ReaxFF molecular dynamics (ReaxFF MD), which can characterize the kinetics of microscopic reactions at the atomic scale, facilitates in-depth investigation of the reaction mechanism of coal pyrolysis, making it a significant research focus. Hence, in this review, we provide comprehensive simulation strategies for ReaxFF MD in coal pyrolysis applications. First, methods for determining the structural characteristics of coal are summarized. We focus on research advances in coal models and propose current model construction strategies, such as modeling, optimization, and validation. Second, the application scope and limitations of various model scales for pyrolysis simulation research are discussed, providing new insights into the effective construction and pioneering development of coal models. Subsequently, we present start-up details for ReaxFF MD simulations and summarize the types of force fields used for coal pyrolysis simulations together with the specifications for their development. Moreover, we focus on simulation strategies for ReaxFF MD in coal pyrolysis applications, including the effects of temperature, heating rate, and simulation time. Third, we mention future development trends and research directions according to the latest progress in coal pyrolysis applications using ReaxFF MD. Finally, the review concludes with a brief discussion of future perspectives.