Relationship between Thermal Conductivity and Chemical Structures of Chinese Coals

Shi, Qingmin; Qin, Yong; Chen, Yilin

doi:10.1021/acsomega.0c02281

Cited by 13 publications

(3 citation statements)

References 33 publications

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“…In the actual situation, the thermal conductivity of coal varies greatly with the environment and its own properties [25][26][27], while in the model, it is impossible to accurately calculate each discrete point, so it is necessary to analyze the influencing factors to the thermal conductivity of coal.…”

Section: Influencing Factors To the Thermal Conductivity Of Coalmentioning

confidence: 99%

A Method for Detection of Fire Source Positions in High-Temperature Areas

Shang¹

2022

IJHT

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Spontaneous combustion of coal is an important disaster that needs to be addressed in the coal mine production process. Since its ignition position is often unknown and concealed, determining the ignition position in the goaf is of great significance to the work safety of the mining area. This study measured the thermal conductivity of coal samples using the spherical thermal conductivity model, and obtains the fitting relationship between the thermal conductivity, the heating voltage U and the inner sphere outer wall temperature t1 by inputting different voltages, and the correlation coefficient R2 was all greater than 0.99. Through analysis of the spherical geometric model, it was determined that the ignition point was at the vertical depth of 16.542m from the highest temperature point in the goaf, and that the distance from the ignition position to the ignition source ranged between 13.49m to 1.03m when the temperature in the goaf was 60℃ to 1700℃. Through comparison with the actual data, the error was found to be 4.7%, indicating that the proposed model was more accurate. Finally, it was found that the thermal conductivity of coal is closely related to the porosity, degree of metamorphism and inhomogeneity of the medium.

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Section: Influencing Factors To the Thermal Conductivity Of Coalmentioning

confidence: 99%

A Method for Detection of Fire Source Positions in High-Temperature Areas

Shang¹

2022

IJHT

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“…A coal mass is an anisotropic non-homogeneous crystalline formation that develops under long-term complex conditions. The natural biochemical structure and composition and degree of water saturation have a significant influence on the original conductivity of coal mass and the type of conductivity (Figure 13) [22,23]. According to solid-dielectric theory, the electrical types of solid medium can be divided into two categories by the type of conductive carriers and the migration mode.…”

Section: Macro-microscopic Mechanism Analysis Of Resistivity Change O...mentioning

confidence: 99%

Spatiotemporal Evolution Characteristics of Apparent Resistivity and Its Response Correlation with Acoustic Emission of Coal under Multi-Step Loading

et al. 2022

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To understand the early warning signs of damage during the coal mass deformation process, an integrated monitoring procedure was designed that combines the apparent resistivity (AR) and acoustic emission (AE) of coal damage under multi-step loading. The spatiotemporal response characteristics of AR and the time-varying evolution of AE were studied and the varying correlation between the two was discussed. Additionally, the macro–microscopic mechanics of the AR response during the coal deformation process was explored. The results show that the AR and AE signals corresponded well with the applied load during the coal deformation process. In the early loading stage, variations in AR and AE signals were not apparent. As the applied load increased, the high-resistance area of AR increased and the AE signals became active. The local variation characteristics of AR could be used to indirectly invert the internal structure of the coal samples. The electrical variation in the loaded coal was mainly controlled by the conductive surface of cracks. The acoustic and resistivity methods can strongly complement the spatial and temporal dimensions of early warning systems for disasters. The AE technique can continuously monitor a test area for abnormal occurrences in the engineering site, and AR tomography images that are obtained can be used to locate inversions in the source coal in order to take pre-emptive action before disaster occurs. This research can provide new ideas for monitoring and early warning systems for coal and rock dynamic disasters.

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“…The TC presents a slow increment at first but then rapidly increases with the increase of temperature (Deng et al, 2017b). The increase in the temperature slightly improves the TC of coals with varying degrees in the temperature range of 30-150 °C, while water with a higher TC than air contributes to the TC of loose coal (Shi et al, 2020).The trend of the TC first increases and then decreases with the change of temperature, and introduced a modeling method for the thermal properties of coal and temperature (Deng et al, 2017a(Deng et al, , 2018. Clearly, although many factors affect the TC of residual coal in goaf, there are few studies on the relationship between these influencing factors and the ETC model of porous medium.…”

Section: Introductionmentioning

confidence: 99%

Effective thermal conductivity of loose residual coal in goaf: Comparative analysis of experiment and model

Zhang

Shen

Wan

2022

Energy Exploration & Exploitation

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The effective thermal conductivity (ETC) model of loose residual coal in goaf is a method to study the heat transfer law of spontaneous combustion in goaf. In order to study the effect of coal particle size and ambient temperature on heat transfer, coal samples of different sizes were taken from the FuSheng (FS) mine, and the void fraction, the thermal conductivity (TC) of the residual coal under different ambient temperature were tested. Additionally, four types of ETC models of loose residual coal in goaf were obtained and the average relative errors of the TC were analyzed. The results showed that the void fraction, the coal particle size and ambient temperature have different effects on the spontaneous combustion of the residual coal. The effect of coal sample size on the heat transfer is 100 times that of the ambient temperature. The changes in the ETC and average relative error of the different models were consistent. The heat transfer in the spontaneous combustion of residual coal has a direct relationship with the spatial distribution and heat transfer modes of the loose residual coal in the goaf.

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Relationship between Thermal Conductivity and Chemical Structures of Chinese Coals

Cited by 13 publications

References 33 publications

A Method for Detection of Fire Source Positions in High-Temperature Areas

A Method for Detection of Fire Source Positions in High-Temperature Areas

Spatiotemporal Evolution Characteristics of Apparent Resistivity and Its Response Correlation with Acoustic Emission of Coal under Multi-Step Loading

Effective thermal conductivity of loose residual coal in goaf: Comparative analysis of experiment and model

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