Effect of Oxygen Concentration on Volatile Precipitation and Critical Ignition Point.

The purpose of this study was to investigate the impact of the oxygen concentration on the ignition of bituminous coal. Different oxygen concentrations and temperatures were used in the large-scale oxidation experiments to collect oxidized coals, which were then extracted with chloroform. And compare the critical ignition temperature of different mass samples. The liquid samples obtained were analyzed by using GC-MS and Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy was also used to characterize extracted oxidized coal. The results revealed that the critical ignition point of bituminous coal decreases by 229.4 °C when the mass sample increases from 5 to 300g. Furthermore, at the same temperature, an increase in the oxygen concentration in the atmosphere was found to enhance the pyrolysis of bituminous coal. The oxidation activity of coal initially decreased and then increased with the temperature rise. The ether bond formed below 150 °C is oxidized and decomposed above 175 °C, which is closely related to the ignition of the coal seam.