Study on the Relation between the Deep and the Spontaneous Combustion of Coal Seam

Di, Jian You; Gao, Er Xin; Sun, Xianfeng; Sun, Chang Q.; Chen, Yu Li

doi:10.4028/www.scientific.net/amr.852.821

Cited by 6 publications

(3 citation statements)

References 1 publication

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“…With increasing burial depth, the oxygen-containing functional groups in the coal structure increase, and the spontaneous combustion tendency of coal is greater. Di J established the relationship between the geothermal gradient and the mine depth and considered that the coal spontaneous combustion ignition period and the mining depth conformed to the Gaussian curve expression (Di et al 2014). When the mining depth reaches 1000 m, the spontaneous combustion period of the coal seam is shortened sharply.…”

Section: Introductionmentioning

confidence: 99%

Study on the evolution law of oxidation characteristics of unloaded coal based on the change of buried depth

Ma,

Duan

et al. 2023

Preprint

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To obtain the change law of oxidation characteristics of unloaded coal at different burial depths, the experimental coal samples were loaded and unloaded with various degrees of stress according to the in situ stress characteristics of the Changcun coal mine in China. Through low-field nuclear magnetic resonance (LNMR) and temperature-programmed experiments, the change law of oxidation characteristic parameters and pore structure parameters of unloaded coal under different stresseswas tested. The main conclusions are obtained through the analysis of the experimental results. ①With increasing burial depth, the oxidation reaction products of unloaded coal under different stresses regularly changed. ② With increasing burial depth, the oxidation characteristics of unloaded coal at different burial depths gradually increased and gradually slowed down after 1200-1600 m, and the concept of the "critical depth" of unloaded coal oxidation characteristics was proposed. ③ With increasing burial depth, the porosity of the unloaded coal body gradually decreased, the number of micropores increased, and the number of small pores, mesopores and macropores gradually decreased. It is further concluded that the difference in oxidation characteristics of unloaded coal at different depths was caused by the change in the number of micropores.

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Section: Introductionmentioning

confidence: 99%

Study on the evolution law of oxidation characteristics of unloaded coal based on the change of buried depth

Ma,

Duan

et al. 2023

Preprint

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“…The combustion process comprises a latent period [ 12 ], a self-heat period [ 13 ], and a combustion period [ 14 ]. Coal seams with a tendency to undergo spontaneous combustion require a certain amount of time after being mined and broken before spontaneously combusting [ 15 – 17 ]. Extensive studies have been conducted on the process of coal spontaneous combustion, its characteristic temperature, indices for combustion, division of the combustion stages, and early warning.…”

Section: Introductionmentioning

confidence: 99%

Division of coal spontaneous combustion stages and selection of indicator gases

Zhang

Yang

et al. 2022

PLoS ONE

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Investigating the division of coal spontaneous combustion stages and the selection of indicator gases is significant to the safe production of coal mines. In this study, the characteristic temperature of coal spontaneous combustion, the generation law of indicator gases, the combustion process, and the division of the combustion stages of coal samples taken from Hongqingliang (HQL) and Dayan (DY) mines were investigated using thermogravimetric analysis experiment, indicator gas detection experiment, and coal oxidation spontaneous combustion experiment. The results of the thermogravimetric analysis experiment showed that the pyrolysis temperatures of the HQL and DY coals were 115.76°C and 131.80°C, and the ignition temperatures were 337.74°C and 360.18°C, respectively. The indicator gas detection results showed that the first-appearance temperature of C2H4 was 85°C for the HQL and DY coals, whereas the first-appearance temperature of C2H6 varied: 115°C for the HQL coal and 130°C for the DY coal. The first-appearance temperatures of C2H2 were 180°C and 195°C for the HQL and DY coals, respectively. The experiments on coal oxidation spontaneous combustion showed that the spontaneous combustion period of the HQL and DY coals were 35.45 and 42.3 days, respectively. The heating process during combustion could be divided into four stages: a latent period of spontaneous combustion, a slow spontaneous heating period, an accelerated spontaneous heating period, and a period of combustion. The critical temperature of each stage showed a good correlation with the incipient temperature of the indicator gases, namely C2H2, C2H4, and C2H6, and the appearance of the above gases can be used to characterize the degree of spontaneous combustion of coal.

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“…Mines worldwide have entered the stage of deep resource exploitation, and the deep mining of coal resources is expected to become the new normal. − The dynamic phenomenon in deep coal mining is evident, the surrounding rock fragmentation phenomenon of roadways is increasing, and the coal seam temperature is expected to rise. The spontaneous combustion period of coal in a deep coal seam is significantly different from that of the shallow, and the increase of coal temperature is an important factor accelerating the spontaneous combustion of the coal seam, which provides oxygen supply and heat storage conditions for natural combustion. − According to statistics, as shown in Figure , China has seen 73 gas explosions and fire accidents in China during the 12th five-year plan period; with a total death toll of 649, this unfortunately ranks China first in coal mine safety accidents. In the mining of deep coal seams, the spontaneous combustion in the gob is known to be serious, whereas the spontaneous combustion induced by negative pressure drainage along the bedding boreholes is becoming prominent, with major safety hazard accidents reported in recent years.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Spontaneous Combustion Hazardous Zone and Analysis of Influencing Factors in Bedding Boreholes of a Deep Coal Seam

Jia

Zhao

et al. 2021

ACS Omega

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Accurately determining the spontaneous combustion zone of coal around the borehole plays an important role in preventing borehole accidents. To solve the problem of dividing the hazardous zone of spontaneous combustion in boreholes, a fully coupled model of the gas flow, coal oxidation reaction, and energy transportation is developed in this study. Taking the drainage borehole of the 24130 working face in the No. 10 Coal Mine of the Pingdingshan mining area as an example, the proposed model is used to simulate the seepage velocity field, oxygen concentration field, and temperature field of the coal around the borehole. The simulation results are found to be consistent with the field test results. Based on the simulation results, the coal around the borehole is divided into two areas in the axial direction of the borehole. The intersection of the seepage velocity u ≤ 0.004 m/s and oxygen concentration 7% ≤ C(O2) ≤ 21% are considered the “hazardous zone”, and the union of the oxygen concentration C(O2) < 7% and seepage velocity u > 0.004 m/s are considered the “safety zone”. The influences of various factors inducing spontaneous combustion of coal around the borehole on the hazardous zone are revealed by analyzing the drainage negative pressure, sealing length, and roadway temperature. The results show that reducing the drainage negative pressure and increasing the sealing length can effectively restrain the spontaneous combustion of the borehole and can also help reduce the scope of the hazardous zone of the borehole. Finally, a reasonable arrangement of the predrainage period in the appropriate season can also effectively inhibit the spontaneous combustion of coal around boreholes.

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Study on the Relation between the Deep and the Spontaneous Combustion of Coal Seam

Cited by 6 publications

References 1 publication

Study on the evolution law of oxidation characteristics of unloaded coal based on the change of buried depth

Study on the evolution law of oxidation characteristics of unloaded coal based on the change of buried depth

Division of coal spontaneous combustion stages and selection of indicator gases

Determination of the Spontaneous Combustion Hazardous Zone and Analysis of Influencing Factors in Bedding Boreholes of a Deep Coal Seam

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