On the Influence of the Forms of the Connection of Methane With the Coal Matrix on the Gas Dynamic Phenomena Arising in the Underground Development of Coal Seams

Смирнов, В. Г.; Дырдин, В. В.; Исмагилов, З. Р.; Kim, T.L.; Manakov, Andrey Yu.

doi:10.26631/arc1-2017-34-41

Cited by 3 publications

(5 citation statements)

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“…The study into the dependence of the energy characteristics of the magnetic fi eld on the external infl uence of physical factors makes it possible to investigate the kinetic parameters of the processes in the molecular structure of the coal substance associated with the macroscopic properties of coal. Geological processes, accompanied by an increase in pressure and temperature, aff ect the state, composition, and properties of coal [16,17]. The absorption of energy by coal substance leads to transformations of its molecular structure, resulting in the structural adjustment of coal substance with the possible release of methane [15,18].…”

Section: Study Problem Statementmentioning

confidence: 99%

Impact of weak electromagnetic fields on the properties of coal substance

Burchak¹,

Soboliev²,

Bezruchko³

et al. 2022

Nauk. visn. nat. hirn. univ.

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Purpose. To establish the regularities of the influence of magnetic fields on the peculiarities of changing the chemical and structural characteristics of the coal substance according to the size of microparticles enriched with vitrinite. To formulate a new system of views on the mechanisms of structural and functional transformations of coal substance under the influence of weak external fields. Methodology. The authors used an electric furnace heating up to 320 K that creates a pulsation magnetic field with a strength of up to 4,000 A/m to process dispersed samples of hard coal with a weak magnetic field. The methods of infrared spectroscopy and electron paramagnetic resonance were used in the research. Findings. Experimental works were carried out to estimate the impact of weak fields on the state and properties of coal substance. It is shown that weak energy fields, and the electromagnetic one in particular, are able to reduce the energy barriers of reactions in coal substance due to spin-spin interaction, which leads to the activation of processes at the atomic-molecular level and interfacial interaction. Originality.It is experimentallyestablished that for coal micro-particles with sizes from 0.16 to 0.1 m, enriched with vitrinite, the coupling coefficient decreases after exposure to an external magnetic field, and for micro-particles with sizes less than 0.63 m, this indicator increases. Such changes are caused by the redistribution of hydrogen between aromatic and aliphatic components during free-radical reactions. Changes in the spectrum on vitrinite (0.160.10 mm), are more significant than on inertinite (0.063<0.05 mm). At the same time, the external action of the electromagnetic field has caused the opposite consequences. It is shownthat magnetically stimulated chemical reactions occurring in the coal substance are aimed at the recombination of free radicals with active surface states of the organic mass of coal into stable gas molecules. The results of laboratory studies using the methods of electron magnetic resonance and infrared spectroscopy and infrared spectroscopy allow assuming that the changes in structural characteristics recorded during experiments with low-energy impacts can be considered as intermediatorsfor the matter transformation or changes in the state of coal in preparation for structural and functional transformations.For example, to the sorption interaction or destructive processes with methane generation. Practical values.The magnetic field effect can be used to develop new research methods for the study on elementary processes by electron spin resonance; control spin-dependent phase transitions. The use of magnetic resonance methods allows the usage of magnetically field effects in the form of basic tools for the research on structural defects. The results obtained will be a scientific ground for the development of methods for estimating the parameters of electromagnetic processes in coal to develop new technologies for the extraction and processing of hydrocarbon energy carriers.

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Section: Study Problem Statementmentioning

confidence: 99%

Impact of weak electromagnetic fields on the properties of coal substance

Burchak¹,

Soboliev²,

Bezruchko³

et al. 2022

Nauk. visn. nat. hirn. univ.

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“…Among the indicated schemes of endothermic reactions ( 23)-( 25), the energetically most favorable is (25). After the shock formation of radicals OH, they participate in subsequent reactions with the formation of atoms and radicals H, O, OH (the continuation and branching of the chain) [59].…”

Section: Conditions Of Self-ignition Of Hydrogen Upon Release Into Atmospherementioning

confidence: 99%

“…We chose the kinetic energy of a hydrogen molecule T H 2 , equal to the modulus of the work function of the molecule from hydrogen (A H 2 < 0), i.e., T H 2 = A H 2 . Then the condition for initiating process (25)…”

Section: Conditions Of Self-ignition Of Hydrogen Upon Release Into Atmospherementioning

confidence: 99%

“…A sudden release of coal and gas brings finely dispersed coal from the face to the mined-out space. A distinctive feature of coal and gas emissions is the presence of finely ground—even down to the nanoscale—coal, the mass of which can be from 20% to 50% of the total outburst mass [ 25 ]. Despite the abundance of papers discussing possible mechanisms for outbursts of coal and gas, the mechanism for generating coal dust remains unknown.…”

Section: Introductionmentioning

confidence: 99%

“…The development of theoretical concepts of gas and coal outbursts in the framework of macroscopic continuum theories (mechanics, hydro- and gas dynamics) over the 20 years following the work published in [ 30 ] did not lead to an explanation of their mechanism and causes [ 18 , 23 , 28 , 31 , 32 ]. Two mysterious phenomena remain unexplained: (1) methane generation in quantities significantly superior to the methane in coal and (2) the dispersion of a significant part of the emitted coal at a nanoscale [ 25 ]. Despite the wide variety of conditions under which gas and coal ejections occur, there is a universal part of these fast and high-energy phenomena associated with the generation of large quantities of gas and fine coal.…”

Section: Introductionmentioning

confidence: 99%

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High-Energy Ejection of Molecules and Gas-Dust Outbursts in Coal Mines

Kaim

2021

Entropy

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In the current work, using the framework of the formalism found in the Bogolyubov–Born–Green–Kirkwood–Yvon (BBGKY) equations for the distribution functions of particle groups, the effective single-particle potential near the surface of the liquid was analyzed. The thermodynamic conditions under which a sudden opening of the liquid surface leads to high-energy ejection of atoms and molecules were found. The energies of the emitted particles were observed to be able to significantly exceed their thermal energy. Criteria of the ejection stability of the liquid surface and the self-acceleration of ejection were formulated. The developed theory was used to explain the phenomenon of the self-acceleration of gas-dust outbursts in coal mines during the explosive opening of methane traps. The results also explained the mechanisms of generating significant amounts of methane and the formation of coal nanoparticles in gas-dust outbursts. The developed approach was also used to explain the phenomenon of the self-ignition of hydrogen when it enters the atmosphere.

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Hypothesis about physical-chemical nature of gas-dynamic phenomena in coal mines

2021

Geoteh. meh.

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Practical experience in the development of a gas-saturated coal-rock massif, as well as the results of scientific research, point to the imperfection of the existing ideas regarding the processes in the extremely stressed coal-rock massif, mechanisms of the occurrence and behavior of gas-dynamic phenomena (GDP). The conducted analysis for the problem state regarding the nature and mechanism of sudden outbursts of coal, rocks and gas, in general, confirm that the outburst hazard was due to the complex interaction of three main natural factors (stress state, gas factor and physical-mechanical properties of rocks) with technological ones, and the formation of outburst hazardous conditions occurs in geological environments that are characterized by certain properties and conditions. The purpose of the paper is to obtain new theoretical understanding of the GDP nature with taking into account geological conditions and the impact of external factors by developing a hypothesis regarding the physicochemical nature of the GDP. It is proved that relief of stresses arisen in the molecular structure under the impact of geological factors leads to the activation of relaxation processes in the substance. The relaxation of the accumulated energy system results in structural transformations with the release of low-molecular-weight compounds. According to this pattern, accumulation of gases genetically connected with fossil organic matter and the emergence of gas-dynamic phenomena.is formed in the coal-rock massif. The key point of the hypothesis is that partial stress relief of the coal-rock massif creates in the fractured zones of the coal bed conditions for relaxation of elastic energy accumulated in the molecular structure of coal, hence, promoting the activation of structural transformations by the free-radical mechanism, which results in the release of low-molecular-weight compounds (methane, in particular). Under appropriate conditions, in the zone of relaxation of elastic deformations, the process can assume an avalanche character, namely, initiate sudden outbursts of coal and gas. According to the physicochemical model of methane release in coal under the impact of geomechanical, geological, and technogenic factors, which is proposed within the framework of this work, partial discharge creates in the coal bed conditions for relaxation of the elastic energy accumulated in the molecular structure of coal. That is, it promotes the activation of structural transformations by the free-radical mechanism, the result of which is the release of low-molecular-weight compounds (methane). Under the condition of sufficiently high fracturing of the elastic deformation zone, the process acquires an avalanche character, that is, sudden outbursts of coal and gas are developed. Keywords: coal, coal mines, gas-dynamic phenomena, outbursts of coal and gas, stress-strain state.

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On the Influence of the Forms of the Connection of Methane With the Coal Matrix on the Gas Dynamic Phenomena Arising in the Underground Development of Coal Seams

Cited by 3 publications

References 0 publications

Impact of weak electromagnetic fields on the properties of coal substance

Impact of weak electromagnetic fields on the properties of coal substance

High-Energy Ejection of Molecules and Gas-Dust Outbursts in Coal Mines

Hypothesis about physical-chemical nature of gas-dynamic phenomena in coal mines

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