Experimental Study of the Source of CO Anomalies in Mines Based on Microscopic Changes

Abstract

The phenomenon of abnormal CO emergence occurred in a working face of Tangshan mine, and the CO source was analyzed from the two perspectives of CO detection method optimization and microstructure changes in the low-temperature environment of the coal body. Then, the critical index system was optimized. The CO identification tube test results and gas chromatograph test results are combined to derive a fitting formula, and the CO identification tube test results are used as the independent variable to obtain the gas chromatograph test results, which can effectively eliminate the error of small CO identification tube test results. The analysis of raw coal and coal samples heated by water bath at 30 °C, 40 °C, and 50 °C was carried out using low temperature liquid nitrogen adsorption and thermogravimetric and infrared spectroscopy experiments. It was found that the pore structure of the coal body developed as the temperature increased; the oxidation reaction occurred in the low-temperature state when heat was absorbed to produce CO. The thermal decomposition of carbonyl group was found to be the main source of CO. Finally, the index of spontaneous combustion of coal is optimized according to the temperature, and the index systems represented by O2/(CO2+CO), CH4 and CO2/CO were determined from 30~80 °C, 90~180 °C and 18~240 °C, respectively.

Keywords

• CO source
• free radical reaction
• CO identification tube
• optimization of self-ignition index