An experimental study for characterization the process of coal oxidation and spontaneous combustion by electromagnetic radiation technique

Kong, Biao; Li, Zenghua; Wang, Enyuan; Lu, Wei; Chen, Liang; Qi, Guansheng

doi:10.1016/j.psep.2018.08.002

Cited by 169 publications

(36 citation statements)

References 43 publications

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“…From the fitting equation between the coal permeability and axial stress in Table , it can be seen that the correlation coefficients between the permeability and axial stress fitting equations under different gas pressures are all greater than 0.97, indicating that the fitting curve is in good agreement with the measured data and the fitting curve is good. These findings can accurately reflect that the permeability of gas‐containing coal increases with the increase of axial stress and has a power function relationship …”

Section: Discussionmentioning

confidence: 69%

“…These findings can accurately reflect that the permeability of gascontaining coal increases with the increase of axial stress and has a power function relationship. 39,40 From Figure 10, it can be seen that the permeability increases with the increase of axial stress under the condition of keeping the radial stress and gas pressure unchanged, and the trend of the coal sample permeability gradually slows down with the increase of axial stress. Because the permeability of gas-containing coal increases with the increase of axial stress, it reveals a macroscopic manifestation of the change in the effective stress of specimens and the continuous expansion of internal cracks in coal.…”

Section: Relationship Between Permeability and Axial Stressmentioning

confidence: 99%

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Study on the change of permeability of gas‐containing coal under many factors

Wang

et al. 2019

Energy Science & Engineering

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The permeability characteristics of gas‐containing coal under different radial stress, different axial stress, and gas pressure were studied by orthogonal experiments, using a self‐developed three‐axis servo fluid infiltration system with a gas‐solid coupling of gas‐containing coal, on the basis of a single‐factor influence on the permeability of gas‐containing coal. By considering the effective stress, three kinds of relationships between permeability and radial stress, permeability and axial stress, as well as permeability and gas pressure were established. The results show that radial stress, axial stress, and gas pressure have a great influence on the permeability characteristics of gas‐containing coal: (a) The influence of radial stress on gas permeability is significant, whereas the influence of axial stress is negligible. The degree of influence of radial stress, gas pressure, and axial stress on the permeability decreases in turn; (b) The permeability decreases following a power function with the increase of the radial stress; (c) The permeability gradually increases with the increase of axial stress. With the increase of axial stress, the permeability increases following a power function; (d) The increase in gas pressure will reduce the effective stress on the coal, and the number of pores and cracks inside the coal body will decrease. This will increase the effective seepage flow and gas flow rate of the gas and eventually lead to the increase of coal permeability. There is a quadratic function relationship between the permeability and gas pressure.

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Section: Discussionmentioning

confidence: 69%

Section: Relationship Between Permeability and Axial Stressmentioning

confidence: 99%

Study on the change of permeability of gas‐containing coal under many factors

Wang

et al. 2019

Energy Science & Engineering

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“…The combined exothermic process of the coal and oxygen oxidation leads to a constant change in the air density. Based on the hypothesis of Boussinesq, 26 this ignores the viscous dissipation and takes into consideration the fact that if all of the other parameters are constant, except for density, the air leakage intensity of the loose coal caused by the air hot pressure is where is the gas density at temperature T (kg/m) 3 ; ρ is the gas density at temperature T (kg/m 3 ); and is the gas expansion coefficient, = −( ∕ T) ∕ .…”

Section: Establishment Of the Asmmentioning

confidence: 99%

“…They burn up a large amount of coal resources, reduce the calorific value of the coal, and are the major source of toxic gas and greenhouse gas emissions . Mine fires caused by spontaneous coal combustion (CSC) in gob accounts for more than 90% of the total number of fires . Because the shear resistance of the top of the coal in the gob is poor, it is easy to produce deformation, fractures, and loose coal in deep mines.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 Mine fires caused by spontaneous coal combustion (CSC) in gob accounts for more than 90% of the total number of fires. [3][4][5][6][7][8] Because the shear resistance of the top of the coal in the gob is poor, it is easy to produce deformation, fractures, and loose coal in deep mines. The location of the loose coal is concealed and is difficult to deal with, which increases the possibility of spontaneous combustion, thus posing a serious threat to safe production in the mine.…”

Section: Introductionmentioning

confidence: 99%

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Study of the influence of the characteristics of loose residual coal on the spontaneous combustion of coal gob

Shu

et al. 2019

Energy Science & Engineering

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Mine fires are becoming a serious issue as the intensity of mining increases, especially in deep mines. Loose coal gob has a hidden ignition location and a high possibility of spontaneous combustion, which makes fire prevention difficult. Therefore, based on the theory of gas seepage and the characteristics of loose coal, a model of air leakage and spontaneous combustion in gob is established in this paper. Using working face #10414 in the Yangliu coal mine as an example, the relationship between the three spontaneous coal combustion (CSC) zones and the three stress zones is analyzed and verified by combining a FLAC3D simulation with field monitoring. In addition, the influence of advancing speed on the CSC is discussed, and suggestions for fire prevention are presented. The results show that the variation in the calorific value of the CSC with increasing degree of looseness of the residual coal in the gob forms an arch‐shape. There is a one‐to‐one relationship between the distribution of the three stress zones and the three CSC zones. In addition, as the advancing speed increases, the contact time between the loose coal body and the air decreases and the possibility of CSC decreases. This study provides a scientific basis for fire prevention and control in mines.

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Effect of coalbed methane airflow with optimum action concentration on coal oxidation under low temperatures

Yang

et al. 2020

Asia-Pacific J Chem Eng

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To explore the effect of coalbed methane (CBM) airflow on coal oxidation under low temperatures, an experimental apparatus was developed and applied to simulate coal oxidation under different oxidizing atmospheres. The formation of carbon monoxide CO, the index gas, in CBM airflow was analyzed to obtain the optimum concentration of CH4 that exerted the strongest influence on coal oxidation. Then, a comparison experiment was performed on coal oxidation in dry air and in CH4 at the optimum concentration by using electron spin resonance (ESR) and Fourier transform infrared (FTIR) technology. The results suggest that 25% of CH4 has the strongest effect on coal oxidation at low temperatures. The free radical concentration (Ng) in coal increases with temperature in both dry air and 25% CH4. At this concentration, CH4 can inhibit the reactivity of coal substantially while raising the excitation temperature. The oxidation of aliphatic hydrocarbons is severely inhibited by 25% CH4, which reduces its consumption rate and abates its decrement in the initial phase. Although 25% CH4 restricts the consumption of –OH and –COOH in oxidation, it promotes the formation of –C–O.

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An experimental study for characterization the process of coal oxidation and spontaneous combustion by electromagnetic radiation technique

Cited by 169 publications

References 43 publications

Study on the change of permeability of gas‐containing coal under many factors

Study on the change of permeability of gas‐containing coal under many factors

Study of the influence of the characteristics of loose residual coal on the spontaneous combustion of coal gob

Effect of coalbed methane airflow with optimum action concentration on coal oxidation under low temperatures

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