Investigation of water influence on coal based on thermal oxidative degradation kinetics

Abstract

In order to further understand the effect of the water content on spontaneous combustion of coal, the thermal oxidative degradation kinetics of coals with different water contents were studied by Kissinger method, Flynn–Wall–Ozawa method, and Starink method. The results show that the water has no substantial effect on the thermal decomposition mechanism of the coal, and reaction orders are similar (n = 1) with different water contents. However, the activation energy Ea of coals has a certain relationship with the water content. When the water content of the coal is less than 6.0 mass%, with the increase of the water content, the activation energy Ea decreases. With the water content of coal exceeding 6.0 mass%, the activation energy Ea is increased with the increase of the water content. The change tendency of activation energy Ea is consistent with the mass increase of coals in the coal oxidation stage, which means that lower activation energy Ea is easier to make spontaneous combustion of coal. From this study, we hope to provide an efficient method for further understanding the mechanism of the water influence on spontaneous combustion of coal.