Comparative study of experimental testing methods for characterization parameters of coal spontaneous combustion

Wen, Hu; Hu, Wang; Liu, Wenyong; Cheng, Xiaojiao

doi:10.1016/j.fuel.2020.117880

Cited by 71 publications

(15 citation statements)

References 23 publications

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“…Coal spontaneous combustion in goaf is one of the main hazards that affect the safety of mine production. , The temperature rise and oxidation of coal spontaneous combustion in goaf is the result of the heat generated by the physical and chemical reactions between the air leakage of the working face and the residual coal in goaf . In the process of mine production, it is the premise of effective prevention and control of coal spontaneous combustion to determine the location of the high-temperature area and points of coal spontaneous combustion in goaf timely and accurately.…”

Section: Introductionmentioning

confidence: 99%

“… 1 , 2 The temperature rise and oxidation of coal spontaneous combustion in goaf is the result of the heat generated by the physical and chemical reactions between the air leakage of the working face and the residual coal in goaf. 3 In the process of mine production, it is the premise of effective prevention and control of coal spontaneous combustion to determine the location of the high-temperature area and points of coal spontaneous combustion in goaf timely and accurately. However, the actual environment of the goaf is complex, and the high-temperature area and high-temperature points are hidden.…”

Section: Introductionmentioning

confidence: 99%

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Study on Multifield Migration and Evolution Law of the Oxidation Heating Process of Coal Spontaneous Combustion in Dynamic Goaf

Lei

Jiang

Bao³

et al. 2023

ACS Omega

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To study the dynamic evolution law of the oxidation heating process of coal spontaneous combustion in the goaf during the advancing process of the working face, a dynamic model of oxidation heating of coal spontaneous combustion in the goaf was established on the basis of deformed geometry. Through numerical simulation research, the evolution and migration laws of seepage field, oxygen concentration field, temperature field, and high-temperature area of coal spontaneous combustion in the goaf during the advancement of the working face was obtained. The results indicate that the distribution of the bulking coefficient, porosity, and permeability of the falling coal and rock mass in the goaf is nonuniform. They are relatively large in the area near the working face and the inlet and return airway and remain relatively unchanged with the advancement of the working face, but they are constantly decreasing in the location of the gob in the middle and deep. The oxygen concentration in the goaf presents an asymmetrical distribution. The oxygen concentration distribution area on the inlet side is wider than that on the return air side. At the same depth of the goaf, the oxygen concentration gradually decreases from the inlet side to the return air side; after the advancement distance exceeds 200 m, the air leakage in the goaf basically disappears, and the oxygen concentration decreases to zero. The high-temperature area of coal spontaneous combustion oxidation in the goaf was mainly concentrated on the air inlet side and extended toward the return air side. The advancing speed has a significant effect on the oxidation heating process of coal spontaneous combustion in the dynamic goaf. Under the same propulsion distance, when the advancing speed is 6 m/day, the highest temperature in the goaf is about 40 °C, and when the advancing speed is 2 m/day, the highest temperature in the goaf is as high as 120 °C. The smaller the advancing speed, the higher the heating rate of the goaf and the closer the high-temperature area to the working surface. The higher the advancing speed, the lower the temperature of the high-temperature point of the goaf and the greater the depth of the high-temperature point of the high temperature area; when the advancing speed is 2 m/day, the highest temperature point in the goaf is 70 m away from the working face, whereas when the advancing speed is 6 m/day, it reaches 174.6 m.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Multifield Migration and Evolution Law of the Oxidation Heating Process of Coal Spontaneous Combustion in Dynamic Goaf

Lei

Jiang

Bao³

et al. 2023

ACS Omega

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“…According to the coal spontaneous combustion mechanism and related literature research, increasing the temperature, increasing the oxygen concentration, and reducing the gas flow rate are beneficial to the ignition of coal. [23][24][25][26][27] Second, in actual production, because the coal seam is far away from the ground, the heat dissipation is large, and it is not easy to raise the inlet gas's temperature. Finally, due to a large amount of heat dissipation, the greater the gas flow rate at the same temperature, the higher the heat carried, and the higher the flow rate will lead a higher gas flow rate.…”

Section: Introductionmentioning

confidence: 99%

Pure oxygen condition forced oxidation ignition process of underground coal gasification

Liang

Zhao

et al. 2023

Asia-Pacific J Chem Eng

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Underground coal gasification without shaft is a technology that uses directional drilling technology to gasify deeply buried coal. The technology first needs to ignite the coal seam during drilling, but as the depth of the coal seam (drilling) increases, it is very difficult to ignite the underground coal seam. In order to ignite the underground coal seam more safely and effectively, the forced oxidation ignition technology has been developed; that is, the coal seam is heated by hot oxygen, and the coal seam is rapidly oxidized and released to ignite the coal seam. Due to the complex confidential environment, it is challenging to ignite underground coal seams. To ignite the underground coal seams more safely and effectively, this paper used a self-made reactor to simulate the forced convection heating of the bituminous coal under different oxygen flow rates with hot oxygen and used a Fourier transform infrared spectrometer flue gas analyzer to detect the outlet gas, used ATR-FTIR spectrometer to analyze the solid residues in different areas, and recorded the time and maximum temperature of coal ignition under other processes. The results showed that low-flow high-temperature oxygen could quickly burn coal seams.When the oxygen flow rate was 2.5 m 3 /h, and the coal seam was ignited when heated to 130 C for 170 min. Through GC-MS analysis of nine flammable components in the tar components under different processes, the content of shortchain aliphatic hydrocarbons in the tar decreases, and the content of benzene series tends to increase. Through ATR-FTIR analysis, the solid sample near the gas injection port contained fewer oxygen functional groups; the middle of the furnace body included the most oxygen functional groups; near the gas outlet contained more oxygen functional groups than the raw coal. CO 2 would rise to 3% when coal was about to ignite.

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“…Spontaneous coal combustion is a complex physical and chemical reaction process that involves interaction between momentum and chemical structures. − The low-temperature oxidation of coal is the primary cause of spontaneous coal combustion. Scholars worldwide have conducted studies on spontaneous coal combustion prevention technologies, including inert gas injections, inhibitors, and fire extinguishing gels. − Inhibitors are physical or chemical based on their action mechanism.…”

Section: Introductionmentioning

confidence: 99%

Effect of Water Evaporation on the Inhibition of Spontaneous Coal Combustion

et al. 2022

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Spontaneous coal combustion is the primary cause of coal mine fires. During the production process, spontaneous coal combustion in the goaf is often affected by air leakage, which weakens or annuls the effect of inhibitors and leads to secondary oxidation. However, the action mechanism of inhibitors on secondary oxidation spontaneous coal combustion remains unclear. Thus, this study analyzes the influence of moisture evaporation on the performance of a high-water-content physical inhibitor (HWPI) using the Carbolite temperature-programmed experiment, differential scanning calorimetry, scanning electron microscopy, and a MINI MR test. The results demonstrate that as the moisture content of the inhibitor decreased, after being treated with the HWPI and drying for 24 h, the concentrations of O 2 , CO, and CO 2 were found to be lower than the gas concentration of raw coal, which showed that although the moisture content is reduced, the treated coal sample still has a lower spontaneous combustion tendency than the raw coal. The apparent activation energy was reduced, and the heat absorption per unit time decreased, which eventually weakened or annulled the effect of the HWPI. Future research should further improve existing inhibitor types to reduce the impact of secondary oxidation on spontaneous coal combustion caused by water evaporation.

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Comparative study of experimental testing methods for characterization parameters of coal spontaneous combustion

Cited by 71 publications

References 23 publications

Study on Multifield Migration and Evolution Law of the Oxidation Heating Process of Coal Spontaneous Combustion in Dynamic Goaf

Study on Multifield Migration and Evolution Law of the Oxidation Heating Process of Coal Spontaneous Combustion in Dynamic Goaf

Pure oxygen condition forced oxidation ignition process of underground coal gasification

Effect of Water Evaporation on the Inhibition of Spontaneous Coal Combustion

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