Rapid gas desorption and its impact on gas-coal outbursts as two-phase flows

Zhou, Aitao; Zhang, Meng; Wang, Kai; Elsworth, D.; Deng, Nan; Hu, Jiaying

doi:10.1016/j.psep.2021.04.042

Cited by 13 publications

(4 citation statements)

References 27 publications

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“…The ratio of the gas diffusing rate from broken coal particles at the initial time to that from intact coal can be related to the coal particle breakage ratio x = R 2 /R 1 from Equation (18):…”

Section: Calculate the Desorption Rate Ratio With Particle Distributionmentioning

confidence: 99%

“…Therefore, deep insights into coal and gas outbursts require analyzing gas desorption rate variations in gas-containing coal pre-and post-crushing. It has already been recognized in addressing the outburst issue that the desorption rate of gas from coal is closely associated with the tendency of coal outbursts [18,19]. The rapid gas desorption from powdered coal plays a decisive role in gas outbursts [20,21].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Cheng,

Huang,

et al. 2024

Applied Sciences

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The gas contained in coal plays a crucial role in triggering coal and gas outbursts. During an outburst, a large quantity of gas originally absorbed by coal is released from pulverized coal. The role this part of the gas plays in the process of coal and gas outbursts has not been clearly elucidated yet. Therefore, investigating the changes in gas desorption rate from coal particles of different sizes could provide some meaningful insights into the outburst process and improve our understanding of the outburst mechanism. First, combining the diffusivity of coal of different particle sizes and the distribution function of broken coal, we present a gas desorption model for fragmented gas-bearing coal that can quantify gas desorption from coal particles within a certain range of size. Second, the gas desorption rate ratio is defined as the ratio of the gas desorption rate from coal being crushed to that from coal before breaking. The desorption rate ratio is mainly determined by the desorption index (γ) and the granularity distribution index (α). Within the limit range of coal particle sizes, the ratio of effective diffusion coefficient for coal particles with different sizes is directly proportional to the reciprocal of the ratio of particle sizes. Under uniform particle size conditions before and after fragmentation, the gas desorption rate ratio is the square root of the reciprocal of the effective diffusion coefficient. The gas desorption model quantitatively elucidates the accelerated desorption of adsorbed gas in coal during the continuous fragmentation process of coal during an outburst.

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Section: Calculate the Desorption Rate Ratio With Particle Distributionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Cheng,

Huang,

et al. 2024

Applied Sciences

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“…At present, people's understanding of coal and gas outburst mechanism is not completely clear. The influential research on the outburst mechanism at home and abroad can be divided into four categories [20][21][22][23][24]. The "comprehensive action hypothesis" is recognized by most people, which states that coal and gas outburst is caused by the comprehensive action of gas, in-situ stress and physical and mechanical properties of coal.…”

Section: Establishment Of Fuzzy Bow-tie Model For Coal and Gas Outburstmentioning

confidence: 99%

Assessment Method of Coal and Gas Outburst: From the Perspective of TFN-MCS Theory<br /> <div> <br /> </div>

Wang,

Xu,

2023

IJEES

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The prediction of coal and gas outburst risk can effectively prevent underground coal mine accidents. Due to the overlapping, coupling and complexity of coal and gas outburst in the development process, coal and gas outburst is generally Gaussian distribution or nearly Gaussian distribution, especially when the sample data in the research area is not accurate or the information is insufficient, the traditional evaluation model and method have certain limitations. To further improve the scientific and accurate prediction of coal and gas outburst risk level, a coupling model of coal and gas outburst risk assessment is established based on Monte Carlo stochastic simulation (MCS) and triangular fuzzy number (TFN) theory. Firstly, the index weight measurement value is determined by using expert opinions and AHP method. Then, the risk level and risk importance of coal and gas outburst risk assessment index are quantitatively described by using fuzzy semantics with five-level classification standards. Finally, the confidence interval of the comprehensive risk value of the coal mines to be evaluated in the research area is established. The research results show that after 20,000 simulation experiments with the coupling model, the calculation results have converged, and the confidence interval value of the system comprehensive risk simulation value of each coal mine is 95%, which can provide relevant decision support for the prevention and control planning of coal and gas outburst.

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“…Coal is a natural porous medium and its internal pore structure is relatively complex which varies greatly with the degree of metamorphism. 1,2 The study and evaluation of the pore structure in coal is the basic premise for accurately mastering the adsorption and desorption characteristics of coal, evaluating the permeability of coal, preventing coal and gas outbursts, and realizing efficient gas extraction. 3,4 Scholars have often examined the pore structure of coal: Jiang et al studied the pore characteristics of coal with different coal structures by low-temperature liquid nitrogen adsorption test.…”

Section: Introductionmentioning

confidence: 99%

Pore and gas desorption characteristics of primary coal with different degrees of metamorphism

Chen

Liu

Wang

et al. 2023

Energy Science & Engineering

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Pore difference characteristics and adsorption/desorption experiments of primary coal with different degrees were explored to study the characteristics of pore structure and gas desorption. The results show that the pore volume increases with the increase in the degree of metamorphism. In primary coal with different degrees of metamorphism, the distribution of micropores, small pores, and medium‐sized pores (by volume) is WY < PM < CY. The distribution of large pore volume and visible pore volume was WY > PM > CY. According to the pore volume distribution law of different metamorphic primary coals, the average pore diameters of WY, PM, and CY were 68.40, 45.60, and 30.50 nm, respectively. The porosity and specific surface area of primary coal with different degrees of metamorphism show a distribution pattern such that WY > PM > CY. For large pore and visible pore, the pore volumes of WY, PM, and CY coal were 0.0785, 0.0587, and 0.0300 mL/g, respectively, and the proportions were 81.86%, 74.49%, and 55.25%, respectively. The porosity of WY, PM, and CY were 11.57%, 9.03%, and 6.57%, respectively, and the specific surface areas were 6.917, 5.826, and 5.611 cm3/g. According to the desorption characteristics of coal bodies with different metamorphic degrees at different time nodes found that the gas desorption at different time nodes shows similar changes under the same adsorption equilibrium pressure. The higher the degree of coal metamorphism, the greater the amount of gas desorption, and the faster the desorption amplitude. The desorption intensity of WY coal is significantly higher than that of PM and CY coal with the increase of desorption time which also verifies the measurement results of pore structure and adsorption constant.

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Rapid gas desorption and its impact on gas-coal outbursts as two-phase flows

Cited by 13 publications

References 27 publications

Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Assessment Method of Coal and Gas Outburst: From the Perspective of TFN-MCS Theory<br /> <div> <br /> </div>

Pore and gas desorption characteristics of primary coal with different degrees of metamorphism

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Rapid gas desorption and its impact on gas-coal outbursts as two-phase flows

Cited by 13 publications

References 27 publications

Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Effect of Coal Particle Breakage on Gas Desorption Rate during Coal and Gas Outburst

Assessment Method of Coal and Gas Outburst: From the Perspective of TFN-MCS Theory&lt;br /&gt; &lt;div&gt; &lt;br /&gt; &lt;/div&gt;

Pore and gas desorption characteristics of primary coal with different degrees of metamorphism

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Assessment Method of Coal and Gas Outburst: From the Perspective of TFN-MCS Theory<br /> <div> <br /> </div>