Study on the Coal-Oxygen Intrinsic Reaction at Low Temperature by the Subtraction Method

Coal oxidation involvescomplex physical and chemical processesas well as many reaction pathways. The subtraction method was usedto investigate the law of the coal-oxygen intrinsic reaction at lowtemperatures. The subtraction method is to subtract the characteristiccurve of the coal reaction in N-2 from the characteristiccurve of coal oxidation in air, which can remove the influence ofpyrolysis reaction, water evaporation, and gas desorption on coallow-temperature oxidation, and ultimately obtain the coal-oxygen intrinsicreaction curve under the pure oxidation pathway. To reveal the internalrelationship of the coal-oxygen intrinsic reaction between the releaseof gas products and the conversion of active functional groups, atemperature-programmed system was used to analyze the law of indexgas products. Furthermore, Fourier infrared spectroscopy was usedto analyze the conversion of active functional groups in the low-temperaturereaction process of coal. The findings revealed that the coal-oxygenintrinsic reaction obtained through subtraction played a significantrole in the release of gas and the conversion of aliphatic hydrocarbonsin the overall process of the coal low-temperature reaction. However,the alterations in the N-2 atmosphere were relatively weak.The gas release of CO and CO2 gradually increased withincreasing temperature, as did the concentration of oxygen-containingfunctional groups, and there was a positive correlation between them.