A model of coal–gas interaction under variable temperatures

Zhu, Wancheng; Wei, Chenhui; Liu, Jishan; Qu, Hao; Elsworth, Derek

doi:10.1016/j.coal.2011.01.011

Cited by 219 publications

(115 citation statements)

References 21 publications

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“…Li ZQ and Xian XF proposed a model of coal gas flow under the combined effects of the stress and temperature (29). Zhu et al developed a coupled model of coal deformation, gas transport and thermal transport to examine the complex coal-gas interactions under variable temperatures (16). Considering the effects of gas pressure and gas desorption of coal.…”

Section: Role Of Thermodynamic Effect On Coal-gas Interactions Duringmentioning

confidence: 99%

“…The fundamental understanding of gas migration and coal self-heating is essential to eliminate their dangers as mining hazards or develop the potential as an unconventional gas resource recovered (11)(12)(13)(14). The evolution of coal-gas interaction processes is a chain of physicochemical reactions in underground pre-and post-mining coal seams, which is labeled as "coupled processes" implying that one reaction process affects the initiation and progress of another (15)(16)(17). This reaction chain is linked together through dominant mechanisms, including compositional gas flow and diffusion, reaction kinetics, energy transport and coal deformation (1,2,15).…”

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confidence: 99%

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Role of thermodynamic effect on coal-gas interactions during underground pre- and post- mining coal seams in the environmental geology

Xia¹

2017

J Environ Geol

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U nderground coal mining generally occurs in the terrifically thermodynamic environment of high geostress and geotherm, resulting in many coal-gas disasters, such as coal-gas outburst, coal spontaneous combustion and even gas explosion etc. (1-3). Geological statistics and relative researches show that when mining depth is over 1000 m, the geotherm will reach the range of 40 and 45°C with the commonly geothermal gradient of 30-50°C/km, and the geostress is 95-135 MPa at 3500-5000 m depth (4). In addition, the geotherm has a significant impact on geomechanics of coal-rock mass: the variation of 1°C within the coal-rock medium may trigger the insitu stress change of 0.4-0.5 MPa (5).Coal-gas disasters pose a difficult, persistent and costly problem for coal industries worldwide, usually causing huge economic losses, personal casualties, perilous land subsidence and massive environmental contamination (6-10). The fundamental understanding of gas migration and coal self-heating is essential to eliminate their dangers as mining hazards or develop the potential as an unconventional gas resource recovered (11)(12)(13)(14). The evolution of coal-gas interaction processes is a chain of physicochemical reactions in underground pre-and post-mining coal seams, which is labeled as "coupled processes" implying that one reaction process affects the initiation and progress of another (15)(16)(17). This reaction chain is linked together through dominant mechanisms, including compositional gas flow and diffusion, reaction kinetics, energy transport and coal deformation (1,2,15). The individual reaction process, in the absence of full consideration of cross couplings, forms the basis of well-known disciplines such as hydrology, chemistry, elasticity and heat transfer (1,15).Advances in our understanding of coal-gas interactions have provided some effective measures to retard or suppress underground coal-gas disasters and enhance potential resource utilization quality. Some typically mathematical models had been established to reveal coupled hydro-mechanical mechanism of coal seam gas flow, such as Palmer-Mansoori model (18), Shi-Durucan model (19), Zhang-Liu model (17) and Xia-Zhou model (20,21) etc., but failed to consider the influence of thermal effect on coal-gas interactions. However, in real coal mining environment, the thermodynamic effect may not only have a significant impact on the micro-and macro-structure evolution of coal-rock mass, but on gas ad/desorption, diffusion and migration behaviors. Thus, the thermodynamic effect should not be ignored in addressing the coal-gas interactions, which has become a kind of common recognition among many contemporary experts and scholars. Levy J et al. carried out an adsorption experiment of some coal sample, which showed that when the gas pressure of the coal sample was 5 MPa and the temperature was the range of 20 and 65°C, the adsorbed quantity of coal gas would be reduced by 0.12 m 3 /t as the temperature increased by 1°C (22). Yin GZ, et al. experimentally studied the influence...

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Section: Role Of Thermodynamic Effect On Coal-gas Interactions Duringmentioning

confidence: 99%

mentioning

confidence: 99%

Role of thermodynamic effect on coal-gas interactions during underground pre- and post- mining coal seams in the environmental geology

Xia¹

2017

J Environ Geol

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“…Yuan et al numerically investigated the spontaneous combustion process of coal in a large-scale coal chamber and focused on the low-temperature oxidation reaction rate [13]. Some studies also discussed the influence of simulated parameters on the rising temperature feature [14,15]. However, correlative studies on the characteristics of the fire source position and its influencing factors combined with various heat dissipation conditions were not found.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental simulation of spontaneous combustion of coal

Yu¹,

Hu²

2017

Int. J. SAFE

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In this paper, our main aims are to make up for the defects of large-scale coal spontaneous heating tests on trial methods. An unsteady-state numerical model is developed to simulate self-heating in a largescale coal spontaneous heating reactor with experimental conditions. The self-heating process of coal is reproduced successfully, and the main characteristics of nonlinear heating and windward movement of the fire source are obtained during the whole process. By comparison, the simulated and experimental results of the Tianchi coal samples show a good agreement with the temperature rise features and fire source positions. This confirms the validity of the model. Based on the model, a sensitivity analysis is constructed to investigate the influence of the external environment on coal spontaneous heating. The main contents include (1) heat dissipation surroundings; (2) air quantity; (3) air direction. The simulated conclusions contribute to optimizing the experimental parameters and obtaining the shortest spontaneous combustion period. In addition, the model is found to be of great significance for predicting the fire source temperature and position in practical coal mine conditions.

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“…The skeleton deformation of coal mass containing gas is widely expected to obey Terzaghi's effective stress principle [7][8][9]. According to the law of conservation of momentum, the equation of stress equilibrium is expressed with effective stress and pore pressure as in which σ ij ' is the effective stress tensor of coal mass containing gas (Pa, i,j=1,2,3), α is Biot's coefficient (=-K/K s ), K is the bulk modulus of coal mass containing gas (Pa), K s is the effective bulk modulus of coal grains (Pa), δ ij is the Kronecker delta as 1 for i=j and 0 for i≠j, p is the pore pressure (Pa), and F i is the body force (Pa).…”

Section: Governing Equations Of Coal Deformationmentioning

confidence: 99%

Research on the Effective Influence Radius of Hydraulic Reaming in Mining Seam

Peng¹,

Wang²,

Li³

et al. 2015

TOEFJ

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Abstract:In Accordance with the present situations suggesting that the construction of the gas drainage boreholes in mining seam is sufficient and the gas drainage effect in low permeability coal seams does not yield perfectly, the hydraulic reaming technology in mining seam was proposed to increase the gas drainage efficiency. Through the gas flow method, the effective influence radius of hydraulic reaming was determined and the fluid-solid coupling model of gas drainage along boreholes after hydraulic reaming was established theoretically. Following this, the changes in the laws of gas content around the boreholes in the coal seam were simulated and analyzed. The results indicated that hydraulic reaming can effectively promote the stress-relief and permeability-increase of the coal mass around the boreholes, and the coal mass around the reaming boreholes can be divided into gas flow increase zone, gas flow delay attenuation zone and fast decay zone. The effective influence radius of hydraulic reaming was 5.5~6 m. The obtained simulation results were basically in accordance with the field investigation.

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A model of coal–gas interaction under variable temperatures

Cited by 219 publications

References 21 publications

Role of thermodynamic effect on coal-gas interactions during underground pre- and post- mining coal seams in the environmental geology

Role of thermodynamic effect on coal-gas interactions during underground pre- and post- mining coal seams in the environmental geology

Numerical and experimental simulation of spontaneous combustion of coal

Research on the Effective Influence Radius of Hydraulic Reaming in Mining Seam

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