Study on the application of coal spontaneous combustion positive pressure beam tube classification monitoring and early warning

Kong, Biao; Cao, Huimin; Lu, Wei; Wen, Jiamin; Yin, Jueli; Zhang, Wenrui; Zhang, Xiaolong

doi:10.1007/s11356-023-27421-3

“…Some alkane gases (CH 4 , C 2 H 6 , C 3 H 8 ) and alkene gases (C 2 H 4 ) are available as predictor gases reflecting coal spontaneous combustion at higher temperatures. Furthermore, Kong et al precisely categorized the CSC process into seven levels of warnings: safety, gray, blue, yellow, orange, red, and black [19,20].…”

Section: Introductionmentioning

confidence: 99%

Study on Spontaneous Combustion Characteristics and Early Warning of Coal in a Deep Mine

Wang,

Du,

Deng

et al. 2023

Fire

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Due to high stress, high ground temperature, high moisture, and other factors in deep mines, the risk of coal spontaneous combustion (CSC) is enhanced, seriously affecting the safety of coal mining. To achieve early prediction of spontaneous combustion in the No. 3 coal seam at the Juye coalfield in the deep mine, this paper employs a temperature-programmed device to analyze the changing pattern of single-index gases and composite gas indices with temperature derived from the gas produced during csc. It also optimizes the index gas of coal sample spontaneous combustion. Simultaneously, the characteristics of coal temperature and a four-level warning indicator system for CSC are determined based on the analysis of indicator gas growth rate method, carbon-to-oxygen ratio, and the characteristics of the indicator gas. The composite index gases of the No. 3 coal seam in Juye coalfield are selected in the initial oxidation stage (Rco), accelerated oxidation stage (R1, G1), intense oxidation stage (R2, G1, G3), and oxidative decomposition stage (G3). This leads to the construction of a six-level warning system consisting of initial warning value, blue, yellow, orange, red, and black levels. Meanwhile, warning thresholds are also established.

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“…During the mining operations in the lower seam, water exploration and discharge in the upper goaf can lead to the displacement of "water and gas" within the goaf, and a large amount of air will enter the goaf through the fissures, which oxidizes the long-term water-soaked and dissolved remnant coal to varying degrees of air-drying (Ma et al 2021). After being soaked and oxidized, the physicochemical properties of the residual coal in the goaf undergo substantial changes, leading to an increase in the risk of its natural ignition, which poses a great threat to the mining of the near-underlying coal seams and the re-mining project in the goaf (Zheng et al 2023;Kong et al 2023). Therefore, it is a particularly important task to investigate the oxidation characteristics of pre-oxidized long-term water immersed coal under different oxygen concentrations.…”

Section: Introductionmentioning

confidence: 99%

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Niu,

Yang,

Sun

et al. 2023

Preprint

0

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In order to study the oxidation characteristics and spontaneous combustion (SC) tendency of pre-oxidized long-term water-soaked coal under different oxygen concentrations, raw long-flame coal (RC), water-soaked 200-day coal (S200), pre-oxidized water-soaked coal at 200 ℃ (O200S200), and pre-oxidized water-soaked coal at 300 ℃ (O300S200) coals were used for the study. The coal spontaneous combustion(SC) program heating test system was adopted to conduct experimental analyses at 21%, 15%, 10%, 5%, 3% oxygen concentration(OC) for experimental analysis. The results show that pre-oxidation water-soaked treatment(PWT) promotes the coal-oxygen complex reaction and increases the rate of coal oxygen consumption(OCR) and the rate of carbon and oxygen compounds production. The rate of CO and CO2 production of the water-soaked(WS) coal increased by 0.329 mol·(cm3·s)−1 and 0.922 mol·(cm3·s)−1, respectively, compared with that of the original coal sample. PWT reduces the activation energy of coal in the low-temperature oxidation stage (the maximum difference can be up to 110.99 KJ/mol) and enhances the oxidizing and heat-releasing capacity. There is a large amount of water in the WS coal, and its cross-point temperature and SC propensity index increased. There was a synergistic effect between the pre-oxidation(PO) and WS treatment, and the lowest comprehensive determination index of the SC propensity of coal in O200S200 samples was 831.92 which was 4.72 lower than that of RC samples, presenting a more SC tendency. Low oxygen concentration has inhibitory effect on the oxidation characteristic parameters of coal, and the apparent activation energy of low-temperature oxidation stage of pre-oxidized water-soaked coal(PWC) increased to 206.418 KJ/mol at 3% oxygen concentration. Both WS and PWT can improve the oxidation activity of coal, and the S200 samples have the most carbon oxides production in the anoxic environment, and the SC risk of the O200S200 samples is the highest. The lower the oxygen concentration of the anoxic environment, the lower the risk of SC of the coal samples. The oxidation characteristics and SC tendency of the PWC under different oxygen concentrations revealed in the study can provide theoretical guidance for the identification and prevention of SC disasters in coal seams with shallow burial and close spacing.

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Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Niu,

Yang,

Sun

et al. 2024

Environ Sci Pollut Res

1

0

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In order to study the oxidation characteristics and spontaneous combustion (SC) tendency of pre-oxidized long-term water-soaked coal under different oxygen concentrations, raw long-flame coal (RC), water-soaked 200-day coal (S200), pre-oxidized water-soaked coal at 200 ℃ (O200S200), and preoxidized water-soaked coal at 300 ℃ (O300S200) coals were used for the study. The coal spontaneous combustion(SC) program heating test system was adopted to conduct experimental analyses at 21%, 15%, 10%, 5%, 3% oxygen concentration(OC) for experimental analysis. The results show that pre-oxidation water-soaked treatment(PWT) promotes the coal-oxygen complex reaction and increases the rate of coal oxygen consumption(OCR) and the rate of carbon and oxygen compounds production. The rate of CO and CO2 production of the water-soaked(WS) coal increased by 0.329 mol•(cm 3 •s) -1 and 0.922 mol•(cm 3 •s) -1 , respectively, compared with that of the original coal sample. PWT reduces the activation energy of coal in the low-temperature oxidation stage (the maximum difference can be up to 110.99 KJ/mol) and enhances the oxidizing and heat-releasing capacity. There is a large amount of water in the WS coal, and its cross-point temperature and SC propensity index increased. There was a synergistic effect between the pre-oxidation(PO) and WS treatment, and the lowest comprehensive determination index of the SC propensity of coal in O200S200 samples was 831.92 which was 4.72 lower than that of RC

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Study on the application of coal spontaneous combustion positive pressure beam tube classification monitoring and early warning

Cited by 6 publications

References 44 publications

Study on Spontaneous Combustion Characteristics and Early Warning of Coal in a Deep Mine

Study on Spontaneous Combustion Characteristics and Early Warning of Coal in a Deep Mine

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

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