Research on coal spontaneous combustion period based on pure oxygen adiabatic oxidation experiment

Spontaneous combustion period is an important characteristic parameter of coal spontaneous combustion. It must be understood to prevent and control coal fire disasters in a coal mine. Fresh coal samples were then collected from the Bulianta Coal Mine in the Shenfu-Dongsheng Coalfield for mini combustion furnace experiments. We then analyzed the changing rules of coal temperature, O2 and CO during spontaneous combustion of coal under pure oxygen adiabatic conditions. A method for calculating oxygen consumption rate during spontaneous combustion of coal under those conditions was then proposed. Based on the Arrhenius law, heat loss rate (RPD) function during coal spontaneous combustion was developed. The coal temperature and oxygen concentration during spontaneous combustion oxidation process of coal in air accurately were calculated from a pure oxygen insulation experiment. When RPDair = 0, 0.2, 0.4, 0.6, and 0.8, the coal spontaneous combustion periods of Bulianta were 15.12, 18.94, 25.25, 37.87, and 75.74 days, respectively. The spontaneous combustion period of Bulianta coal, which was measured using 2-t experimental furnace for coal spontaneous combustion, was 16.66 days. The temperature change curve for spontaneous ignition experiment is similar to the adiabatic condition (RPDair = 0). This demonstrates that the coal spontaneous combustion period calculation method in air using pure oxygen adiabatic experiment is valid.