Research on a Gas Index Reflecting the Sorption Process on Carbon Materials in Coal Mines

Based on the concentration of gases such as propylene and ethylene in the atmosphere of a mine, it is possible to assess the development of a mine fire. With the increase of coal temperature, an increased emission of these gases has been observed. However, the experiment results presented in this paper prove that the use of propylene and ethylene for the prediction of the spontaneous combustion of coal have some limitations. It was found that during a flow of gas mixture through the sorption column, propylene and ethylene were sorbed on coal. This phenomenon manifests in smaller amounts of gases at the outlet of the sorption column. By comparing the concentration of ethylene to propylene at the inlet of the column, it was concluded that the ratio was usually below 3, whereas the range of the ratio at the end of the column was between 0.6–353. The value of gases ratio changed depending on the type of coal material in the column. The results of this experiment provide useful information that the quantitative relation between ethylene and propylene concentrations may indicate the occurrence of the sorption process on carbon materials in coal seams.