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This paper had experiments on lignite and bituminous coal, respectively. The characteristic temperature points were obtained at the oxygen concentration of 5%?10%?15%?17%? 21% and 30% when the heating rate was 10K/min, respectively. The coal ignition decreased as oxygen concentration increased. Coats-Redfern integral formula was utilized to calculate the activation energy from ignition temperature to end temperature of the combustion. It revealed that the activation energy increased along with oxygen concentration increasing. And the activation energy of lignite was less than bituminous coal, and spontaneous combustion of lignite occurred more easily. For the same coal sample, TG curve drifted to the left with the increase of oxygen concentration. It indicated that within a certain range the increase of the oxygen concentration shorted the reaction time, the coal sample was more likely to catch fire. [ABSTRACT FROM AUTHOR]

To investigate the characteristics of adiabatic oxidation phase and build the prediction model of coal spontaneous combustion critical point, the adiabatic oxidation experiment data of eight coal samples are given in this paper, based on the adiabatic oxidation experiment, element analysis experiment and industrial analysis experiment. The phase heating rates of adiabatic oxidation of these samples are also calculated. Then using the thermodynamic parameter calculation method, Tr0.05 and TΔmax are defined and obtained. Furthermore, based on the Levenberg-Marquardt method, the relationship between the coal element content, volatility, the phase heating rate of adiabatic oxidation and Tr0.05 are established. The results show that the content of N or S correlates positively with Tr0.05 Osand that O, C, or H content correlates negatively with Tr0.05. However, the link between these elements and stage-heating rate is the opposite. The law also suggests that stage-heating rate will be much faster and coal spontaneous combustion will be easier when Tr0.05 becomes much lower. The more volatile coal is, the lower Tr0.05, and the more likely it is to spontaneously combust. [ABSTRACT FROM AUTHOR]