Effect of pore characteristics on coalbed methane adsorption in middle-high rank coals

Liu, Xianfeng; He, Xueqiu

doi:10.1007/s10450-016-9811-z

Cited by 89 publications

(49 citation statements)

References 63 publications

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“…22 The Langmuir volume (V L ) is mainly affected by micropores, and it increases linearly with the increasing specific surface areas of the micropores, while, the Langmuir pressure (P L ) is influenced by the combined effects of micropores and mesopores. 23 In previous research on the impact of coal composition and pore structure on gas adsorption, the impact of coal composition and pore structure was investigated without considering the 3D spatial distribution and geometrical morphology of the pore structure, [24][25][26][27] which is unreasonable because coal composition is related to the adsorption capacity of unit internal pore surface while the pore structure morphology is related to the total gas adsorption amount and the hysteresis between desorption and adsorption isotherms, which was found in this paper. As a result, to better understand gas adsorption in coal, the role of coal composition and pore structure in be investigated based on the coal's 3D nanopore structure.…”

Section: Introductionmentioning

confidence: 86%

“…A positive correlation between gas sorption capacity and pore surface fractal dimension was found . The Langmuir volume ( V L ) is mainly affected by micropores, and it increases linearly with the increasing specific surface areas of the micropores, while, the Langmuir pressure ( P L ) is influenced by the combined effects of micropores and mesopores …”

Section: Introductionmentioning

confidence: 99%

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Impact of coal composition and pore structure on gas adsorption: a study based on a synchrotron radiation facility

2019

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A better knowledge about the impact of coal composition and pore structure on gas adsorption is of great significance for coalbed methane exploration and uneconomic coalbed CO2 storage. Coal is a porous medium with complex organic components, and most pores in coal are nanopores that have a complex geometrical morphology. As a result, it is significantly necessary to investigate the impact of coal composition and pore structure on gas adsorption based on coal 3D nanopore structure. Synchrotron radiation nano‐computed tomography (CT) was applied to acquire 3D coal nanopore structure and synchrotron radiation small‐angle X‐ray scattering (SAXS) was used to obtain the pore surface fractal dimension. The coal with higher pore surface fractal dimension presents higher Langmuir volume. Based on the 3D nanopore structure acquired by synchrotron radiation nano‐CT, gas adsorption capacity was characterized by the adsorbed gas amount on unit pore surface area. It was found that gas adsorption capacity depends on the coal composition. There is a negative correlation between gas adsorption capacity and ash content and oxygen‐containing groups, and a positive correlation between gas adsorption capacity and vitrinite contents. Hysteresis between desorption and adsorption isotherms is dependent upon the ratio of throat number to pore number, and the hysteresis becomes more significant when the ratio is larger. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Impact of coal composition and pore structure on gas adsorption: a study based on a synchrotron radiation facility

2019

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“…When the pH changes from 6 to 9, Lc and La decrease and then increase, and reach a minimum of 15.38 and 33.50 nm at a pH of 7. 31 The peak near 1,021 cm− 1 is related to quartz. The decrease of Lc and La occurs because F I G U R E 6 Scanning electron microscopy image after bioconversion at different pH microorganisms have a degrading effect during biological metabolism, which exacerbates the degree of nondirectional alignment of coal macromolecular structures in space and reaches a maximum for the sample #2 conditions.…”

Section: X-ray Diffractionmentioning

confidence: 99%

“…All coal samples had similar spectra, which indicates that samples from both regions contain similar functional groups. 31 The peak near 1,021 cm− 1 is related to quartz. The peak at 1,429 cm −1 that is caused by bond rotation is the characteristic absorption peak of calcite, and the absorbance and intensity decrease after bioconversion.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Influence of bioconversion on pore structure of bituminous coal

Chai

Zhou

et al. 2020

Asia-Pacific J Chem Eng

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Microbial-enhanced coalbed methane is a feasible technique to improve gas recovery and achieve antipenetration, and the coal pores determine the gasadsorption capacity and permeability. To study the pore structure of bituminous coal before and after microbial treatment mercury intrusion porosimetry, nitrogen-gas adsorption, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy was used. The results showed that the microbial treatment increased the macropores volume of the high volatile bituminous coal and sub-bituminous coal, and decreased the micropore and mesopore volume. The porosity increased by 33.80% and 22.89% for the high volatile bituminous coal and sub-bituminous coal, respectively. The effect of bioconversion on the pore structure increases as the degree of coal evolution increases. Because of bioconversion, the oxygen-containing functional groups and the degree of coal crystallization were reduced and the organic matter was degraded, which lead to an enhancement of the pore connectivity. The optimal pH of the nutrient solution for microbial changes to the pore structure was 7. Compared with pure water, the reference of mine water to configure the nutrient solution was more conducive to microbial activity and had a greater impact on the pore structure. K E Y W O R D Scoalbed methane, bituminous coal, pore structure, pH, bio-enhancement

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“…The specific surface area of coal shows a close relationship with methane absorption capacities. Generally, the coal with larger specific surface area has stronger gas absorption ability (Guo et al, 2016;Liu and He, 2017;Sun et al, 2015). The distribution of the specific Figure 6.…”

Section: Pore Distribution Characteristics Of the Coal Samplesmentioning

confidence: 99%

Pulverization characteristics of coal affected by magmatic intrusion and analysis of the abnormal gas desorption index on drill cuttings

Chen

Wang

et al. 2017

Adsorption Science & Technology

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The gas desorption index of drill cuttings is a basic index that measures the initial desorption capacities of coal seams and predicts coal seam gas outbursts. Following a long period of gas drainage in the No.7 coal seam of the No.86 mining area in the Haizi coal mine, the gas desorption index of drill cuttings was still found to be much higher than the threshold value for outburst risks. This abnormal phenomenon led to the present study of the rational selection of test methods and objects in this context. In this study, particle size distribution, pore structure and gas desorption characteristics of coal samples in anomalous areas were analyzed. We found that desorption characteristics are related to particle size and particle size varies in relation to tectonic stress and magmatic intrusions. It appears that the anomalous readings are related to particle size of the coal, resulting from tectonic/magmatic pulverization. Furthermore, measured particle size of drill cuttings is not actually reflective of coal particle size-larger particles may be comprised of multiple smaller particles. The results show that coal samples with particle size <1 mm accounts for 76.3% of total samples and coal samples with particle size >1 mm only accounts for 23.7% of total samples. The porosity and total pore volume increase as the particle size decreases. The specific surface area increases with decreasing pore diameter. Transitional pores and micropores increase the specific surface area of the coal sample

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Effect of pore characteristics on coalbed methane adsorption in middle-high rank coals

Cited by 89 publications

References 63 publications

Impact of coal composition and pore structure on gas adsorption: a study based on a synchrotron radiation facility

Impact of coal composition and pore structure on gas adsorption: a study based on a synchrotron radiation facility

Influence of bioconversion on pore structure of bituminous coal

Pulverization characteristics of coal affected by magmatic intrusion and analysis of the abnormal gas desorption index on drill cuttings

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