Methane adsorption-induced coal swelling measured with an optical method

Tang, Shuheng; Wan, Yi; Duan, Lijiang; Xia, Zhaohui; Zhang, Songhang

doi:10.1016/j.ijmst.2015.09.011

Cited by 24 publications

(11 citation statements)

References 19 publications

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“…After reaching a pressure of 12 MPa, the cell was degassed under vacuum, and we repeated the aforementioned pressurization cycle a second time. More information related to our experimental technique for recording the sorption-induced swelling of coal can be found in previously published work …”

Section: Experimental Methodsmentioning

confidence: 99%

“…More information related to our experimental technique for recording the sorption-induced swelling of coal can be found in previously published work. 19 In order to minimize the relative error in the length measurement, we only measured the strain along the long axis of each specimen. The volumetric swelling per unit volume for the specimen at each pressure step is defined as…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…As a result, the coal macromolecular network expands. Using the same batch of coal specimens, Tang et al measured the swelling in CH 4 at pressures up to 12 MPa and found that the maximum volumetric swelling varies from 2.73% to 3.21%, 19 which are lower than those in CO 2 by 20% to 28%. Given that only the physical interaction occurs between the coal and CH 4 , we deduced that the physical interaction rather than the chemical interaction between the coal and CO 2 dominates the swelling behavior.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

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A Comprehensive Explanation to CO₂-induced Coal Swelling

Duan

Xia

et al. 2020

Energy Fuels

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After exposing dry high-volatile bituminous coal, low-volatile bituminous coal, and anthracite to CO2, we measured the swelling properties of the coal in two pressurization cycles with a maximum pressure of 12 MPa. The viewpoint of physicochemical interactions between the coal and CO2 was used to explain these observations for the first time. Due to the irreversibility of the chemical interactions, the swelling process is also irreversible. At medium to high pressures, the compressional environment is stronger than the magnitude of the swelling; as such, the maximum swelling occurs at 10 MPa. The magnitude of the swelling increases with the coal rank, indicating more drastic breakage of the associative bonds in the coal macromolecule. We attribute anisotropic swelling to the anisotropic bond density in the directions perpendicular and parallel to the bedding plane. In the second pressurization cycle, more gases enter the coal macromolecule at the same pressure, which cause higher strains than those of the first run. The swelling anisotropy slightly weakens in the second pressurization run because the expansion perpendicular to the bedding plane is mitigated. Since the coal rearranges to a more homogeneous structure, the anisotropic swelling is obvious at all pressures.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: ■ Experimental Methodsmentioning

confidence: 99%

Section: ■ Experimental Methodsmentioning

confidence: 99%

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A Comprehensive Explanation to CO₂-induced Coal Swelling

Duan

Xia

et al. 2020

Energy Fuels

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“…Coalbed methane (CBM) is a safety hazard as well as an energy resource to coal mining industry. , On the one hand, it permeates most coalbeds, rendering a danger of gas explosion and outbursts. , Also, methane’s “greenhouse gas” potential is much greater than CO 2 , so its release during coal mining and processing is a concern. , Furthermore, the release of CBM in the openings can significantly increase the ventilation expense. On the other hand, CBM can be used to generate electricity, either at mine sites or can be piped to commercial utilities. , Therefore, CBM recovery before coal extraction is desirable …”

Section: Introductionmentioning

confidence: 99%

“…Coalbed methane (CBM) is a safety hazard as well as an energy resource to coal mining industry. 1,2 On the one hand, it permeates most coalbeds, rendering a danger of gas explosion and outbursts. 3,4 Also, methane's "greenhouse gas" potential is much greater than CO 2 , so its release during coal mining and processing is a concern.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Coal Petrophysical Properties under Microwave Irradiation Stimulation for Different Water Saturation Conditions

Lin

Chen

et al. 2017

Energy Fuels

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Coalbed methane (CBM) reservoirs generally have very low permeability and requires 8 stimulation to make gas extraction economical. Hydraulic fracturing has been widely applied to enhance 9 CBM productivity, but this technology has a number of key limitations, including fractures only propagate 10 along existing joints, large amount of water usage, and potential environmental impact. Microwave 11 irradiation technology can likely overcome the above limitations. In this study, the effect of microwave 12 irradiation on the petrophysical properties of an unconstrained bituminous coal was comprehensively 13 investigated through a suite of integrated diagnostic techniques including Nuclear Magnetic Resonance and 14 X-ray Computed Tomography. A series of experiments were conducted both on centrifuged samples and on 15 samples with different water contents ranging from 1 to 15%. The mineral removal and moisture 16 evaporation due to the microwave selective heating lead to the enlargement, opening, and interconnection 17 of coal pores. The NMR-determined porosity increases linearly with the microwave power while grows 18exponentially with respect to water contents. When the water content is above 6%, the porosity increases 19 by around 98~211%. The fracture volume and coal permeability increase while the P-wave velocity 20 decreases with increasing water contents. Microwave irradiation is effective in enlarging mesopores and 21 macropores and in enhancing the pore connectivity. The significant enhancement of coal permeability and 22 pore fracture structure indicates that the microwave irradiation is effective in improving gas productivity 23 thus has the potential to become a new CBM reservoir simulation technology. 24 25

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Coupled variation of pressure and temperature for methane adsorption in coal seam under three initial pressures

Geng,

Liu,

Zhang

et al. 2024

Adsorption

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The methane adsorption test of coal under three initial pressures of 0.50MPa,0.75MPa and 1.00MPa was carried out using the coal bed adsorption simulation test system, and the change law of CH4 gas pressure and coal bed temperature under three initial pressures was studied. The distribution law of methane gas pressure and coal seam temperature on the inner plane of coal seam and the coupling relationship between them are studied by interpolating and plotting the collected data with MATLAB software. The results show that the methane pressure decreases with time, the coal seam temperature increases with time, and there is no linear correlation between the decrease of pressure and the increase of temperature. When coal is adsorbed, the pressure and temperature in the central region are lower, and the temperature in the region with high pressure is also higher, and the distribution of pressure and temperature is synchronized. The higher the initial pressure, the higher the temperature of the coal seam, the more methane adsorbed by the coal, but the strength of the adsorption capacity of the coal can not be measured simply by the amplitude of the pressure drop. The research content can be used as the basis for further investigation of methane occurrence rule in coal seam and evaluation of methane adsorption capacity of coal.

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Methane adsorption-induced coal swelling measured with an optical method

Cited by 24 publications

References 19 publications

A Comprehensive Explanation to CO₂-induced Coal Swelling

A Comprehensive Explanation to CO₂-induced Coal Swelling

Evolution of Coal Petrophysical Properties under Microwave Irradiation Stimulation for Different Water Saturation Conditions

Coupled variation of pressure and temperature for methane adsorption in coal seam under three initial pressures

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Methane adsorption-induced coal swelling measured with an optical method

Cited by 24 publications

References 19 publications

A Comprehensive Explanation to CO2-induced Coal Swelling

A Comprehensive Explanation to CO2-induced Coal Swelling

Evolution of Coal Petrophysical Properties under Microwave Irradiation Stimulation for Different Water Saturation Conditions

Coupled variation of pressure and temperature for methane adsorption in coal seam under three initial pressures

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A Comprehensive Explanation to CO₂-induced Coal Swelling

A Comprehensive Explanation to CO₂-induced Coal Swelling