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ABSTRACT
Air humidity has a significant effect on the characteristic parameters and heat changes of the coal spontaneous combustion process. In this study, a self-built precision humidity-generating device with adjustable humidity was used to investigate the effect of different humidity conditions on the spontaneous combustion process of coal. The release of indicator gases was determined by a humidity-generating unit in conjunction with a temperature-programmed device for coal oxidation, and the effect of air humidity on coal spontaneous combustion was studied from a macroscopic perspective. A quantitative study of the effect of air humidity on the heat released during the spontaneous combustion of coal was carried out by obtaining data for exothermic heat release intensity by conducting thermal analysis. Meanwhile, the numerical simulation method was used to study the influence of air humidity on the heat released during the coal spontaneous combustion process. The experimental results indicated that the introduction of moist air could significantly increase the oxygen consumption rate of the coal samples and promote the production of CO and CO2. In the slow oxidation stage, the air humidity has a greater effect on the heat release than that in the accelerated and fast oxidation stages. The simulated results of heat release in the slow oxidation phase are consistent with the experimental data, verifying that the moisture in the air can increase the amount of heat release and promote the coal-oxygen reaction. When the moisture in the air first came into contact with the coal, it released a large amount of adsorption heat in a short time, which increased the coal temperature.
Disclosure statement
No potential conflict of interest was reported by the author(s).