Expansion energy of coal gas for the initiation of coal and gas outbursts

An, Fenghua; Yuan, Yu; Chen, Xiangjun; Li, Zhiqiang; Li, Liyang

doi:10.1016/j.fuel.2018.07.132

Cited by 127 publications

(37 citation statements)

References 30 publications

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“…Taking into account considerable sorption capacities of coal and its low porosity at the same time, the ratio of the sorbed gas to the free gas is high. In spite of its small share in the total amount of gas contained in rock, it is the free gas that plays a key role in the initiation of an outburst [4], as it is the source of energy necessary to crush the rock material and partly to give the crushed rock the kinetic energy [5], which initiates the transportation of the post-outburst mass. As a result of the outburst, the coal is finely crushed and the gas pressure surrounding the newly formed grains decreases dynamically from the value corresponding with the original pore gas pressure to the pressure of the mine atmosphere.…”

Section: The Nature Of Gas and Rock Outburstmentioning

confidence: 99%

“…Energies 2019, 12,1999 2 of 23 kinetic energy [5], which initiates the transportation of the post-outburst mass. As a result of the outburst, the coal is finely crushed and the gas pressure surrounding the newly formed grains decreases dynamically from the value corresponding with the original pore gas pressure to the pressure of the mine atmosphere.…”

Section: Gas Stressmentioning

confidence: 99%

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Methane Emission during Gas and Rock Outburst on the Basis of the Unipore Model

et al. 2019

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The goal of this paper is to analyze the phenomenon of gas emission during a methane and coal outburst based on the unipore Crank diffusion model for spherical grains and plane sheets. Two occurrences in the Upper Silesian Coal Basin were analyzed: an outburst in a Zofiówka coal mine in 2005 and an outburst in a Budryk coal mine in 2012. Those two outbursts differed considerably. The first one was connected with an unidentified tectonic disturbance in the form of a triple, interlocking fault, and the other one is an example of an outburst in an area free from tectonic disturbances. The model analysis required laboratory tests in order to determine the sorption properties of coals from post-outburst masses. Sorption isotherms and the values of the effective diffusion coefficient were specified. The post-outburst masses were subjected to sieve analysis and the grain composition curves were plotted. The researchers also used the measurement data provided by proper mine services, such as the methane content, the volume of post-outburst masses, and the time courses of CH4 concentration changes in excavations. They were recorded by methane measurement systems in the mines.

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Section: The Nature Of Gas and Rock Outburstmentioning

confidence: 99%

Section: Gas Stressmentioning

confidence: 99%

Methane Emission during Gas and Rock Outburst on the Basis of the Unipore Model

et al. 2019

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“…A coal and gas outburst is an extremely complex gas dynamic phenomenon during which a large amount of pulverized coal is suddenly ejected from a mining face into a roadway or stope in a very short time, accompanied by large amounts of gas, which can destroy underground equipment. With the mining depth increasing by an annual average growth of 10 m-30 m, the proportion of coal and gas outburst disasters has also gradually increased [1][2][3][4]. Since the first recorded coal and gas outburst accident, the former Soviet Union, Japan, China, Poland, and more than 20 countries have invested a large amount of resources to carry out research on the mechanism of coal and gas outbursts, and these countries have accomplished abundant achievements [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Energy Condition and Quantitative Analysis of the Occurrence of a Coal and Gas Outburst

Dai

Liu

Cao

et al. 2019

Shock and Vibration

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With mining depths increasing, coal and gas outburst disasters are becoming more and more serious and complicated, which directly restricts the production efficiency of coal mines. In order to study the rules of energy dissipation during the occurrence of a coal and gas outburst based on the occurrence mechanisms, a simulation experiment of a coal and gas outburst with a ground stress of 16 MPa and a gas pressure of 0.5 MPa was carried out using a self-developed large-scale coal and gas outburst simulation experimental system. A quantitative analysis was given based on the energy model. The results showed the following: (1) In the process of the coal and gas outburst, the main energy source originated from the elastic potential energy of the coal body and the gas internal energy. The main energy loss was used for coal crushing and throwing. (2) The outburst coal sample in this experiment had a mass of 18.094 kg, and the relative outburst intensity was 1.21%. Additionally, the farthest throwing distance of the outburst coal samples was 3.3 m away from the outburst hole wall. The distribution of the outburst coal sample decreased along the roadway, and the proportion of the coal sample grain size in each area first decreased and then increased with the decrease of the grain size. The coal samples with a grain size less than 0.2 mm after the outburst accounted for 6.34% of the mass of the total coal samples. (3) The elastic potential energy of the coal body accounted for 0.34% of the total outburst energy, while the gas internal energy accounted for 99.66%. It was verified that gas internal energy was the key energy source for the coal and gas outburst, and this internal energy was two orders of magnitude more than the elastic potential energy, playing a leading role in the outburst process. After the outburst initiation, most of the energy was consumed in coal crushing, which was in the same order of magnitude as the gas internal energy. Moreover, the energy losses due to friction, vibration, and sound during the outburst process comprised no more than 10% of the total energy. The research results can provide certain guidance for clarifying the mechanism of a coal and gas outburst and the quantitative analysis of outburst energy.

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“…14 By and large, the phenomenon of outbursts is the process of coal energy dissipation, 15,16 which is accompanied by instantaneous ejection of pulverized coal and gas. 14 By and large, the phenomenon of outbursts is the process of coal energy dissipation, 15,16 which is accompanied by instantaneous ejection of pulverized coal and gas.…”

mentioning

confidence: 99%

“…accelerated with the presence of high gas pressure. 14 By and large, the phenomenon of outbursts is the process of coal energy dissipation, 15,16 which is accompanied by instantaneous ejection of pulverized coal and gas. Most of the outbursts accidents are associated with coal gas pressure, especially in China, combining with other parameters, it is predominated in outbursts identification, and with threshold of 0.74 MPa to indicate the outbursts prone of the coal seams.…”

mentioning

confidence: 99%

The research of coal seam gas pressure and initial gas emission characteristics of borehole

Zeng

Tian

et al. 2019

Energy Science & Engineering

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Gas pressure is one of the major factors to characterize the outburst danger of coal seams. Generally, the process of gas pressure determination is complicate and cannot ensure the accuracy of results, which may cause a wrong identification of outburst danger. This paper discussed and revealed a positive correlation between initial gas emission and gas pressure, which provides a new approach to identify the outburst danger by initial gas emission. Through theoretical analysis and numerical simulation, the liner equation of gas pressure and initial gas emission was deduced. Laboratory experiments under adsorption and desorption of CO2 and N2 were performed using coal samples from Weishe coal mine. The data of initial gas emission under different gas pressure were recorded, and the fitting curves were obtained. The results show a positive correlation between initial gas emission and gas pressure, and the curve of N2 was below the CO2. Especially, while the adsorption gas pressure was under 0.663 and 0.675 MPa, the difference of corresponding initial gas emission was only 0.01 L/s, which indicates the high degree of correlation. The results validated the theoretical and practical feasibility to identify the coal and the gas outbursts through initial gas emission.

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Expansion energy of coal gas for the initiation of coal and gas outbursts

Cited by 127 publications

References 30 publications

Methane Emission during Gas and Rock Outburst on the Basis of the Unipore Model

Methane Emission during Gas and Rock Outburst on the Basis of the Unipore Model

A Study on the Energy Condition and Quantitative Analysis of the Occurrence of a Coal and Gas Outburst

The research of coal seam gas pressure and initial gas emission characteristics of borehole

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