Study on the hybrid explosion mechanism of multicomponent combustible gas-coal dust in a coal spontaneous combustion environment

Abstract

As coal mining depths increase, gas and coal dust explosions triggered by spontaneous coal combustion have become more severe, particularly with multiple combustible gases involved. This study investigated the kinetic mechanism of hybrid explosions combining multiple combustible gases and coal dust through experiments and theoretical analysis. Using a custom experimental setup, we examined three key factors: coal types, dust concentration, and gas components, measuring explosion temperature, pressure, and flame propagation velocity. Results showed that coal dust volatile content significantly influenced explosion characteristics, with higher content increasing temperature, pressure, and flame velocity. An optimal coal dust concentration for maximum explosion intensity was identified, showing an inverse relationship with gas concentration. Carbon monoxide’s impact was primarily determined by the ratio between methane concentration and its chemical equivalence value. FTIR analysis of explosion products revealed that gas-phase component changes significantly affected reaction processes, including pyrolysis and non-homogeneous combustion. Through thermodynamic dimensionless parameters Bi and Da, we quantified heat transfer dynamics and reaction kinetics, providing insights into energy dissipation patterns and supporting the development of environmentally sustainable safety protocols for coal extraction operations.