Simulation of molecular reaction kinetics of gas and coal dust mixture explosion suppression by MPP based on machine learning potential

Abstract

It is of great significance to explore the explosion suppression mechanism of methane coal dust mixture at molecular scale. In this paper, the microscopic mechanism of melamine polyphosphate (MPP) inhibiting the explosion of methane coal dust mixture was studied by the method of reactive molecular dynamics (ReaxFF MD) based on machine learning potential (ML). The results show that MPP can effectively inhibit the chemical reaction chains •CH₃ + •OH → •CH₄O → •CH₃O →•CH₂O → •CHO → CO, •CHO + •OH → •CH₂O₂ → •CHO₂ → CO₂ and CH₄ + •OH → •CH₃ + H₂O by trapping •OH, thus reducing the generation of •CH₃ and the consumption of CH₄. After introducing MPP, two new reaction pathways, •OH+NH₃ →•NH₂ + H₂O and H₃PO₄ → HPO₃+H₂O, were added to the system, which promoted the formation of H₂O. The existence of MPP delayed the fracture process of C–C and C = C bonds in coal molecular structure.