Thermal Behavior of the Low-temperature Secondary Oxidation of Coal under Different Pre-oxidation Temperatures

Wang, Kai; Gao, Peng; Sun, Wei; Fan, Haohao; He, Yunzhong; Han, Tao

doi:10.1080/00102202.2020.1828378

Cited by 26 publications

(9 citation statements)

References 46 publications

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“…Through experimental studies, these authors also expressed that the thermal diffusion coefficient of the oxidized coal increased linearly with an increase in the pre-oxidation temperature. Wang et al , concluded that the pre-oxidation temperature exhibited a significant dual impact of first inhibition and then promotion of the secondary coal oxidation through a temperature-programmed experimental system and a C 80 microcalorimeter, which was consistent with the research result of Jo . Wang et al also discussed the influence of the pre-oxidation degree on the coal spontaneous combustion parameters, and their study revealed that the pre-oxidation process exhibited positive and inhibitive impact on the spontaneous combustion parameters during the initial and later stages of the coal–oxygen composite reaction, respectively.…”

Section: Introductionsupporting

confidence: 53%

Combustion Kinetics and Mechanism of Pre-Oxidized Coal with Different Oxygen Concentrations

et al. 2021

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The phenomenon of spontaneous combustion of “oxidized coal” is common in mining processes of goafs, thick coal seams, and unsealing of closed fire areas. In order to study the reburning characteristics of coal with different oxidation degrees, the oxygen concentration in the pre-oxidation process was selected as the key influencing factor. Thermogravimetric analysis (TGA) and in situ Fourier-transform infrared (FT-IR) spectroscopy were used to study the macro- and microcharacteristics of raw and oxidized coal during the combustion stage. The results showed that the pre-oxidation treatment exhibited a dual effect on promoting and inhibiting the weight loss characteristics of oxidized coal. The apparent activation energy, E a, of the combustion reaction for the utilized coal samples was calculated using the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods, and it was found that the average apparent activation energy (E a̅) values of the oxidized coal samples were less in magnitude than that of the raw coal and that the coal sample with the pre-oxidized oxygen concentration of 15% was more prone to the combustion reaction. Using the correlation determination method of key active groups in the proposed coal combustion reaction, the key active groups affecting the weight change of the tested coal samples during the combustion stage were determined as −CH3 and C–O. The results can be helpful to prevent and control coal spontaneous combustion during re-mining and unsealing of closed fire areas.

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Section: Introductionsupporting

confidence: 53%

Combustion Kinetics and Mechanism of Pre-Oxidized Coal with Different Oxygen Concentrations

et al. 2021

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“…The residual coal in the overlying goaf is subjected to secondary oxidation by air leakage from fractures, which makes the overlying goaf more prone to spontaneous combustion. 11 The toxic and harmful gases produced in the goaf of the upper coal seam will also enter the lower coal seam, which will seriously affect the safety of the workers in the lower coal seam; 12 therefore, it is important to develop management measures to control the emissions of toxic and harmful gas from goafs during close-distance coal seam mining. 13,14 At present, most scholars mainly use the theories of gas seepage, diffusion, and coupling in goafs to conduct numerical simulations to study the seepage and migration laws of gases in goafs during mining.…”

Section: Introductionmentioning

confidence: 99%

“…The toxic and harmful gases released during coal mining and those emitted from goafs seriously impact the production of coal mines and the health and safety of workers, and they can also cause fires, explosions, and other accidents. − Especially for the exploitation of close-distance coal seams, due to the influence of secondary mining, many interlayer fissures are produced, and a large number of air leakage channels are formed, − which cause gas migration in the upper and lower goafs. The residual coal in the overlying goaf is subjected to secondary oxidation by air leakage from fractures, which makes the overlying goaf more prone to spontaneous combustion . The toxic and harmful gases produced in the goaf of the upper coal seam will also enter the lower coal seam, which will seriously affect the safety of the workers in the lower coal seam; therefore, it is important to develop management measures to control the emissions of toxic and harmful gas from goafs during close-distance coal seam mining. , …”

Section: Introductionmentioning

confidence: 99%

Distribution Characteristic and Migration Mechanism of Toxic Gases in Goafs during Close-Distance Coal Seam Mining: a Case Study of Shaping Coal Mine

Wang

Zhang

et al. 2022

ACS Omega

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It is imperative to have an in-depth understanding of the gas migration mechanism during close-distance coal seam mining, not only to prevent fires in the coal industry but also to propose safety strategies for controlling toxic gases. The 1818 working face of the Shaping Coal Mine was used as an exemplary close-distance coal seam mine. Through the construction of boreholes and the arrangement of bundle pipes in the two parallel grooves of the working face and the upper goaf at the corresponding positions in the working face, the gases in the upper and lower goafs were monitored online timely. The firsthand information about the gas distribution was obtained through on-site tests, which provided the robust data for studying the migration mechanism of toxic gases during close-distance coal seam mining. By studying the spatial distribution of harmful gases in the upper goaf without mining the overlying coal, the static distribution law of gas was obtained. By discussing the spatial distribution and migration of harmful gases in the goaf of the overlying coal seam during mining, the dynamic distribution law of the gas was obtained. By studying the spatial distribution and migration of toxic gases in the mined-out area of the lower coal seam during mining, the dynamic distribution of gases in the mined-out area of the lower coal seam was obtained. Moreover, the migration mechanism of gas emission from the goafs in the close-distance coal seam was explored. By analyzing the factors responsible for the accumulation of toxic gases in the return air corner, feasible safety measures were also proposed to prevent this hazard during close-distance coal seam mining.

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“…The raw materials of coal, with different geological ages and different metamorphic degrees, are different, and the internal composition, structure and properties of coal also show corresponding changes, which lead to different characteristics of coal oxidation and combustion processes [ 14 ]. Current researches on the combustion characteristics of stone coal usually use coal samples of different geological ages as fuel [ 15 ], to study the combustion kinetics [ 16 ] or to find ways and means to purify flue gas and ash from burning process for the purpose of utilization [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Enrichment and Chemical Speciation of Vanadium and Cobalt in Stone Coal Combustion Products in Ankang, Shanxi Province, China

Cui

Meng

et al. 2022

IJERPH

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Stone coal enriches more elements compared to other coals, especially Vanadium (V). The content of Co is relatively low, while its environmental risk is relatively high. This study collected the stone-coal samples to investigate the enrichment characteristics and the chemical speciation in the combustion products of V and Co in stone coal at an open-pit coal mine in Ankang City, Shanxi Province, China. A simulation combustion experiment and sequential chemical extraction were conducted. Mineral composition was analyzed for raw-stone coal and its combustion products. The results showed that most of V and Co are mainly enriched in combustion products during the combustion process, the enrichment capacity of Co is higher than V. With the increase in the combustion temperature, the bioavailable chemical speciation of V in stone coal combustion products increased, while Co decreased. If the combustion products are stored without effective treatment, the surrounding environment will be polluted, and then human health might be endangered.

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Thermal Behavior of the Low-temperature Secondary Oxidation of Coal under Different Pre-oxidation Temperatures

Cited by 26 publications

References 46 publications

Combustion Kinetics and Mechanism of Pre-Oxidized Coal with Different Oxygen Concentrations

Combustion Kinetics and Mechanism of Pre-Oxidized Coal with Different Oxygen Concentrations

Distribution Characteristic and Migration Mechanism of Toxic Gases in Goafs during Close-Distance Coal Seam Mining: a Case Study of Shaping Coal Mine

Enrichment and Chemical Speciation of Vanadium and Cobalt in Stone Coal Combustion Products in Ankang, Shanxi Province, China

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