Effects of Coal Deformation on Different-Phase CO2 Permeability in Sub-Bituminous Coal: An Experimental Investigation

Zhang, Beining; Liang, Weiguo; Ranjith, P.G.; He, Wenjun; Li, Zhigang; Zhang, Xiaogang

doi:10.3390/en11112926

Cited by 7 publications

(3 citation statements)

References 56 publications

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“…The Datong coalfield is located in the north of Shanxi Province, China (Figure 1), with a total area of 1827 km 2 from 39°52′ to 40°10′ north latitude and 112°49′32″ to 113°9′30″ west longitude. 29 It consists of two coal-bearing strata: the upper Jurassic coal-bearing stratum with 60.8 Gt of coal reserves and the lower Carboniferous and Permian coal-bearing stratum with 369.1 Gt of coal reserves. It is a main large-scale coalfield in China, as well as one of the potential CO 2 sequestration sites.…”

Section: Methodsmentioning

confidence: 99%

Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

et al. 2018

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CO2 sequestration in deep unminable coal seams is currently identified as a research hot spot to reduce CO2 emissions, due to the potential large-scale storage capacity and complicated physical and chemical reactions, especially for supercritical CO2 (scCO2). Hitherto, the interaction mechanisms between scCO2 and coal mass in situ conditions are still unclear. Therefore, the main objective of this study is to fully address the coupling effects of scCO2 sequestration on coal mass and provide a comprehensive evaluation of the interrelation of these variations. Five cycles of helium and scCO2 injection were replicated on a subbituminous coal sample to investigate the permeability variation with scCO2 saturation time. Meanwhile, gas chromatography–mass spectrometry (GC–MS), gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR), proximate analysis, and low-pressure–temperature nitrogen (N2) isotherm analyses were employed to characterize the transformation in coal mass. The test result shows the following: (1) scCO2 tended to mobilize a higher proportion of aliphatics than aromatics, and the concentration of the yielded hydrocarbons decreased with CO2 saturation time. (2) Carbonate and silicate cemented minerals were partly dissolved due to the formation of an acidic solution containing H2CO3. (3) The hydrocarbon extraction and mineral dissolution resulted in the corresponding FTIR absorbance bands being weakened and the volatile matter content and the ash content being decreased by approximately 15 and 26%, respectively. (4) The coal pore volume and the Brunauer–Emmett–Teller (BET) surface area decreased by approximately 24 and 12%, respectively. (5) Due to CO2 adsorption and the reduction of Young’s modulus with saturation time, the volumetric strain increased from 0.23 to 3.26%, which led to coal permeability decrease from 0.042 to 0.029 mdarcy. After analysis of the interrelation of these variations, the interaction mechanisms between scCO2 and coal mass in situ conditions were described and an overall negative effect on coal permeability was found.

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Section: Methodsmentioning

confidence: 99%

Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

et al. 2018

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“…When CO 2 transitions from gaseous to supercritical state, the swelling of the coal matrix only increases by about 6%. 59 Therefore, there is no need to worry about more ScCO 2 being adsorbed and causing a significant deformation of the coal matrix, leading to a substantial decrease in permeability.…”

Section: Comparison Between Gaseous Co 2 and Supercritical Comentioning

confidence: 99%

“…Although CO 2 has a stronger ability to cause coal expansion after adsorption, experimental evidence has shown that the majority of volume deformation occurs during the gaseous CO 2 adsorption stage, accounting for approximately 94%. When CO 2 transitions from gaseous to supercritical state, the swelling of the coal matrix only increases by about 6% . Therefore, there is no need to worry about more ScCO 2 being adsorbed and causing a significant deformation of the coal matrix, leading to a substantial decrease in permeability.…”

Section: Comparison Between Gaseous Co2 and Supercritical Co2mentioning

confidence: 99%

Characterization of Methane Extraction during ScCO₂-ECBM: Consideration of Competitive Adsorption of ScCO₂ and CH₄

Wang,

Liu,

2023

ACS Omega

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The supercritical CO2 enhanced coalbed methane (ScCO2-ECBM) technology is still in the development stage, and many simulation experiments and theoretical studies related to ScCO2-ECBM are being improved. Previous research works have conducted many studies on the competitive adsorption of CO2 and CH4 in coal, but there is less research on the competitive adsorption of ScCO2 and CH4 and its impact on methane extraction characteristics. In this study, a permeability model considering the competitive effects of effective stress and adsorption swelling on permeability was established. Based on the assumed conditions and permeability evolution model, different injected pressure and initial methane pressure conditions were set to obtain quantitative results of the competitive adsorption of ScCO2 and CH4, permeability changes, and CH4 production. By obtaining the competitive adsorption relationship between ScCO2 and CH4, we analyzed the evolution law of permeability and its impact on CH4 production. It was found that ScCO2 has a stronger competitive adsorption capacity, and the competitive adsorption capacity of ScCO2 and CH4 is more sensitive to injected pressure. Under two different conditions, it was found that the higher the injected pressure or injected differential pressure, the higher the initial permeability. However, due to the greater sensitivity of the competitive adsorption capacity of ScCO2 and CH4 to injected pressure, the greater the injected pressure in the later stage, the greater the decrease in permeability, resulting in a situation where the permeability at an injected pressure of 10 MPa is lower than that at an injected pressure of 8 MPa. A simple comparison was made between gaseous CO2 and ScCO2, and it was found that although injecting ScCO2 has a stronger adsorption swelling capacity that affects permeability changes, its stronger adsorption capacity can effectively displace methane and higher injected pressure, injected temperature, and advantages such as fracturing and extraction that are not yet reflected in the model. This study provides some guidance for numerical simulation of the ScCO2-ECBM process and the enhancement of coalbed methane extraction.

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Experimental measurements of CO2 adsorption on Indonesian low-rank coals under various conditions

Tambaria

Sugai

Anggara

2022

J Petrol Explor Prod Technol

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In this study, the CO2 adsorption capacity was measured on Indonesian low-rank coals in the raw and dry conditions in powder and block states using different coal sample preparation to estimate CO2 sequestration and storage potential. Coal sample specimens were taken from three different areas in the South Sumatra Basin, Indonesia. The adsorption experiments were performed using the volumetric method at a temperature of 318.15 K and pressure up to 3 MPa. The CO2 excess adsorption capacity of powder coal is always higher than block coal. Moreover, decreasing moisture content by the drying process increases CO2 adsorption capacity on coal. Based on fitted CO2 adsorption experimental data with the Langmuir and Freundlich isotherm model, the adsorption occurs on monolayer and multilayer at various conditions. Langmuir volume capacity and pressure show drying and crushing process increased adsorption capacity. However, the drying process affects more the capability of coal to adsorb CO2 than the powdered sample, especially in low-rank coal. It was also observed adsorption capacity is directly proportional to huminite content in the coal. Due to lower moisture and higher huminite contents, the dried WB coal powder had the highest CO2 adsorption capacity over the other coal samples in similar sample conditions. Altogether, this study may provide a better understanding in CO2 adsorption on low-rank coal with different coal sample preparation resulting in different CO2 adsorption capacity.

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Effects of Coal Deformation on Different-Phase CO2 Permeability in Sub-Bituminous Coal: An Experimental Investigation

Cited by 7 publications

References 56 publications

Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

Characterization of Methane Extraction during ScCO₂-ECBM: Consideration of Competitive Adsorption of ScCO₂ and CH₄

Experimental measurements of CO2 adsorption on Indonesian low-rank coals under various conditions

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Effects of Coal Deformation on Different-Phase CO2 Permeability in Sub-Bituminous Coal: An Experimental Investigation

Cited by 7 publications

References 56 publications

Coupling Effects of Supercritical CO2 Sequestration in Deep Coal Seam

Coupling Effects of Supercritical CO2 Sequestration in Deep Coal Seam

Characterization of Methane Extraction during ScCO2-ECBM: Consideration of Competitive Adsorption of ScCO2 and CH4

Experimental measurements of CO2 adsorption on Indonesian low-rank coals under various conditions

Contact Info

Product

Resources

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Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

Coupling Effects of Supercritical CO₂ Sequestration in Deep Coal Seam

Characterization of Methane Extraction during ScCO₂-ECBM: Consideration of Competitive Adsorption of ScCO₂ and CH₄