Mixed reforming of methane with CO2 and H2O: Thermodynamic analysis and ReaxFF Molecular dynamics simulation

Under the dual drivers of the global energy crisis and the carbon neutrality objective, the efficient utilization of carbon-rich industrial waste gas has emerged as a critical strategic approach to advancing sustainable development. In this paper, the effects of reaction temperature, pressure and raw gas composition on the products of methane mixed reforming were systematically studied by combining thermodynamic equilibrium calculations with ReaxFF simulation. Particular attention was given to the regulatory role of CO₂ in steam methane reforming and the synergistic effect of H₂O in dry reforming of methane. The results show that the percentage of target gas increases with temperature but decreases with increasing CO₂ concentration and system pressure. Carbon deposition analysis indicates that carbon formation declines at elevated temperatures, particularly above 1200 K, where the introduction of CO₂ or H₂O significantly inhibits carbon deposition. In steam methane reforming, CO₂ addition decreases the H₂/CO ratio, with its utilization enhanced by temperature but suppressed by pressure. In dry reforming of methane, water has little effect on the H₂/CO ratio below 1200 K, becoming active only at higher temperatures and its utilization similarly declines under elevated pressure. Only above 1200K does the addition of extra water and carbon dioxide become beneficial. By elucidating reaction pathways and the behavior of key intermediates, this study provides theoretical insights into the efficient conversion of carbon resources during methane-mixed reforming. It establishes a scientific basis for the operational control of industrial-scale reforming reactors.