Gas Content and Structure of Coal in Donets Basin

Ulyanova, E.V.; Malinnikova, O. N.; Burchak, A. V.; Balalaev, A. K.; Baranovsky, V. I.

doi:10.1134/s1062739117042643

Cited by 6 publications

(5 citation statements)

References 10 publications

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“…The three-level: Sub-bituminous (SB), High volatile bituminous (HVB) and Low volatile bituminous (LVB) metamorphism factor (Rank) reliably affects most of the researched coal parameters. 4, etc. The analysis of the simultaneous influence of these two factors with a reduced number of beds for the full plan of the experiment showed the absence of accurate effects for all dependent variables.…”

Section: Results and Their Discussionmentioning

confidence: 99%

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Change of parameters in molecular structure of Donbas coals under the influence of external factors

et al. 2019

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The molecular structure of coal is estimated by 13 parameters of infrared spectra, electron paramagnetic resonance, volatile yield and ash content. A new criterion of hydrophobicity is applied, which has shown its informativeness in analyzing the molecular structure of coals of various ranks. It is more sensitive to changes in coal rank than the standard index of volatile yield. The coalification process leads to a significant increase in this index due to the water release and other hydroxyl-containing compounds from the substance of coal. Two-way analysis of variance showed that the influence of the metamorphism factor is significant for 9 molecular parameters. The strongest effects are manifested in the sorption capacity, the criterion of hydrophobicity and the number of paramagnetic centers. The stratigraphic factor does not have a significant impact on one of the molecular parameters. Factor analysis by the method of principal components of the molecular structure of coal showed that the most significant independent factors are metamorphism and sedimentation conditions, the latter ones include independent processes: accumulation of mineral components, decomposition of biomass and geochemical environment during the sedimentation period.

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Section: Results and Their Discussionmentioning

confidence: 99%

“…Most of these indexes are often used to characterize the substance of coal [2][3][4]. In addition, a new criterion for the hydrophobicity of undisturbed coals is introduced here.…”

Section: Methodsmentioning

confidence: 99%

Change of parameters in molecular structure of Donbas coals under the influence of external factors

et al. 2019

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“…Gas generation in the process of coalification is the result of complex physicochemical transformations in the coal substance at the macro-, micro-, nano-and atomic-molecular levels of the structural hierarchy in the coal seam [1]. However, the complexity, diversity and metastability of coal structures lead to the fact that the study of such transformations by classical empirical-theoretical methods is difficult.…”

Section: Methodsmentioning

confidence: 99%

Gas generation by coal matter in contemporary conditions

2019

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A new approach for the study of processes at the atomic-molecular level occurring in the current situation in fossil carbonized organics was proposed. A new phenomenological model of physicochemical transformations in a metastable coal substance with the emission of fluids has been developed. The proposed physic/chemical model is based on the genetic connection of coal methane with fossil organic matter and determines the conditions for the activation of structural transformations in coalmines. This model describes the possible options for the coal/gas system development in the current situation. The accumulation of thermal and mechanical energy by coal in the form of structural stresses in an amount, sufficient to activate free-radical reactions, was experimentally established. In the undisturbed coalrock massif the processes of the coal molecular structure transformation have the relaxation character. The result of relaxation of the accumulated energy in the conditions of a gas-saturated coalrock massif is the methane generation by coal. Gas generation in the process of coalification, in its essence, is the energy response of the system to the action of external geomechanical options (temperature and pressure), by the way of releasing the accumulated additional energy with the emission of gaseous products and the destruction of the solid phase in the organic matter of the coal.

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“…As mentioned above, a lot of research work has been carried out and more results have been achieved on the effect of the moisture content on coal gas desorption and emission characteristics. − Most of the experiments were conducted on coals with the same degree of metamorphism, and no systematic research has been carried out on coals across the rank range. − Based on the existing results, this paper carries out a study on the influence of different moisture contents on the initial velocity of gas emission in the coal body for three different metamorphic degree coal samples (lignite, bituminous coal, and anthracite) to reveal the mechanism of the influence of moisture in depth. The results of the study are of great significance for the prevention and control of gas hazards, outburst prediction, and risk assessments. − …”

Section: Introductionmentioning

confidence: 99%

Investigation on the Gas Emission Law of Water-Containing Coal across the Rank Range

Wang,

Huang,

Liu

et al. 2024

ACS Omega

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Water commonly occurs in coal reservoirs, and it can block the gas flow channels. This has a significant influence on methane transportation within coal. To reveal the gas emission law of water-containing coal across the rank range, three typical coal samples with different coal ranks covering lignite to anthracite were selected in this work. The initial velocity of gas emission (ΔP) under the effect of moisture was measured, and the combination of scanning electron microscopy and mercury injection method was adopted to study the pores and fracture characteristics within coal. Distribution features of oxygen-containing groups in coal were explored by X-ray photoelectron spectroscopy. The microscopic influence mechanism of the water content on ΔP in coal was also comprehensively elucidated. The experimental results show that the moisture content has an obvious inhibitory effect on the ΔP of coal, but the degree of influence on different coal rank samples was different. As the pore space of anthracite (sample XJ) is developed with numerous gas transportation channels, the ΔP has less changes at the lower moisture content (<4.36%). When the moisture content is >4.36%, a large number of water molecules will band together to form water clusters, hindering the gas release, thus greatly reducing the ΔP. However, the change of lignite (sample SL) shows an inverse trend to that of anthracite. Its ΔP is sensitive to the moisture content due to the small number of pores and low porosity. In addition, a great number of oxygen-containing groups in lignite can also provide good surface hydrophilicity for water molecules, and even a small amount of the moisture content (<3.21%) can block most of the pore and facture channels within coal, leading to the remarkable decrease in ΔP. For bituminous coal (sample ML), the distribution of pores and oxygen-containing groups is the most uniform, and the ΔP decreases linearly with the increase in the moisture content.

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Gas Content and Structure of Coal in Donets Basin

Cited by 6 publications

References 10 publications

Change of parameters in molecular structure of Donbas coals under the influence of external factors

Change of parameters in molecular structure of Donbas coals under the influence of external factors

Gas generation by coal matter in contemporary conditions

Investigation on the Gas Emission Law of Water-Containing Coal across the Rank Range

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