Steam reforming mechanism of methane using thermodynamics and molecular dynamics

Abstract

With the growing influence of the greenhouse effect, achieving carbon neutrality has become an urgent priority. Methane has garnered significant attention due to its characteristics as a greenhouse gas and high hydrogen content. Nickel-based catalysts are widely used for methane cracking, but carbon deposition significantly deactivates nickel, thereby hindering the future development of steam reforming of methane. This study investigates the effects of temperature, pressure, and feed ratio on reaction through thermodynamic calculations and molecular dynamics simulations. The results indicate the concentrations of target gases composed of hydrogen and carbon monoxide, as well as the carbon deposition amount, are inversely proportional to pressure and feed ratio. As the temperature increases, the target gas content rises, whereas carbon deposition decreases. According to the carbon resistance of the catalyst, it was proposed to choose low temperature and low pressure (1073K, 1atm) for high-performance catalyst, and high temperature and medium pressure (1200K, 5atm) for ordinary performance catalyst. Methane and water gradually remove hydrogen atoms, and the resulting intermediate product reacts to form CHO and then CO. At high temperatures, increasing the amount of water has a significant effect on reducing carbon deposition. By elucidating the reaction mechanism and quantifying carbon deposition, theoretical foundations are provided to promote industrial development.