Thermodynamic and molecular dynamics study of methane dry reforming

The carbon neutrality strategy presents both challenges and opportunities for the metallurgical industry. Hydrogen, recognized as a green energy source, demonstrates significant potential for application in metallurgy. The negative impact of carbon deposition on catalysts is a significant challenge in the large-scale industrial application of methane dry reforming to produce hydrogen-rich reducing gases for ironmaking. This paper investigates the reaction mechanism through thermodynamic calculations and molecular dynamics simulations, systematically examining the effects of temperature, pressure, and feed ratio on the composition of gas products and the amount of carbon precipitation during the preparation process of hydrogen-rich reduction gas. The optimal conditions to produce high-quality reducing gas are identified to be a CO₂/CH₄ ratio of 0.8 at 1100K and 1 atm. At elevated temperatures, increasing the amount of carbon dioxide can reduce the amount of precipitated carbon, while the opposite is true at lower temperatures. The carbon absorbed by the nickel-based catalyst primarily originates from methane, while hydrogen ions activate carbon dioxide to produce carbon monoxide or carboxyl groups. By elucidating the reaction mechanism and quantifying the carbon precipitation, we provide theoretical guidance for industrial application.