Investigation of the kinetics of spontaneous combustion of the major coal seam in Dahuangshan mining area of the Southern Junggar coalfield, Xinjiang, China

Abstract

In the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T3 declined with decreasing particle size. After the sample with 0.15–0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.

Risk identification of coal spontaneous combustion based on COWA modified G1 combination weighting cloud model

“…The higher the moisture content in coal, the higher the degree of coal looseness, and the higher the oxidation rate 13 . When sulfur in coal is oxidized at low temperature, the expansion of coal is loose, the oxidation area of coal is increased, and its decomposition products enhance the oxygen absorption of coal 14 . Therefore, the higher the sulfur content of coal, the easier coal spontaneous combustion.…”

Effects of organic sulfur on oxidation spontaneous combustion characteristics of coking coal

“…Accidents caused by the spontaneous combustion of coal could be severe, and the resulting losses of high-quality coal are financially significant. In view of the serious harm caused by the spontaneous combustion of coal, scholars worldwide have extensively studied the mechanisms of this spontaneous combustion (Chou, 2012;Dacka SW et al, 1984;Deng et al, 2015a;Hu et al, 2015;Ma et al, 2019;Qi et al, 2018;Shen and Zeng, 2021;Zhao et al, 2021a;Zhao et al, 2021b;Zhou and Tang, 2018;Zhu et al, 2019). Sulfur is a harmful element in coal, and it not only produces hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) in the combustion process, causing environmental pollution, but is also important in restricting the utilization of coking coal resources (Li et al, 2018).…”

The structural transformation and reburning characteristics of gas coal in Ningwu coalfield fire

“…Coal field fire burned a large amount of coal resources (Cheng et al, 2021;Shen and Zeng, 2021;Zhang et al, 2020d;Zheng et al, 2020b), indirectly caused tens of times of the stagnant resources unexploited, produced a large number of greenhouse gases and toxic and harmful substances seriously harm the local ecological environment and groundwater resources (Zhang et al, 2004(Zhang et al, , 2020cHu, 2008, Zhong et al, 2008).…”