Changes in Pore Structure of Coal Associated with Sc-CO2 Extraction during CO2-ECBM

Chen, Run; Qin, Yong; Wei, Chongtao; Wang, Linlin; Wang, Youyang; Zhang, Pengfei

doi:10.3390/app7090931

Cited by 28 publications

(25 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generally, the micropore volume has exhibited a decreasing trend after ScCO 2 exposure, when the intensity of the matrix swelling has been observed to be stronger than the other effects. Instead, the micropore volume has been found to increase (Chen et al., 2017; Zhang et al., 2017a). However, for the dry coals, numerous studies have shown that ScCO 2 exposure cannot significantly change the PSD of the micropores of coals (Figure 4).…”

Section: Effects Of Scco2 On the Pore Morphology Of Coalsmentioning

confidence: 99%

Influences of supercritical carbon dioxide fluid on pore morphology of various rank coals: A review

Zhang

Wang

et al. 2020

Energy Exploration & Exploitation

View full text Add to dashboard Cite

Supercritical carbon dioxide is known to change the pore structure of coals and thus affect their carbon dioxide sequestration capacity. In this study, supercritical carbon dioxide dependence of pore morphology of coals was reviewed. Results indicated that the micropore surface area and volume of dry coals varied between –20% and 20% after exposure to supercritical carbon dioxide. Changes in the micropore size distribution of dry coals after supercritical carbon dioxide exposure were not found to be significant; however, the change in meso- and macropores with diameter of 2–8 nm was observed to be significant. Supercritical carbon dioxide and H2O exposure mainly influenced pores with diameters of 0.4–0.7, 0.7–0.9 and 2–8 nm. The variation in the pore fractal dimensions of the coals ranged from –0.5% to 0.5% after supercritical carbon dioxide exposure. Furthermore, the dependence of supercritical carbon dioxide on the pore structure of coals relies on the coal rank. The change in the pore structure of the coals after supercritical carbon dioxide exposure was observed to be related to the following aspects. First, supercritical carbon dioxide induced swelling in coal matrix, thus reducing the pore surface area and volume of the coal matrix and compressing the cleat system. Next, the extraction of supercritical carbon dioxide mobilised the small organic molecules dispersed in the coal matrix; this increased the pore volume, particularly of micropores. Finally, the mineral dissolution/precipitation also changed the pore structure of the coals. To further examine supercritical carbon dioxide dependence of coal pore morphology, the following studies should be performed. The characterisation of the chemical and pore structure of coals should be combined with existing coal structure models to account for the mechanism of supercritical carbon dioxide changing the pore structure of coals. Combination of physical experiments and numerical simulations is recommended to predict the changes in porosity and permeability of coals due to long-term carbon dioxide sequestration.

show abstract

Section: Effects Of Scco2 On the Pore Morphology Of Coalsmentioning

confidence: 99%

Influences of supercritical carbon dioxide fluid on pore morphology of various rank coals: A review

Zhang

Wang

et al. 2020

Energy Exploration & Exploitation

View full text Add to dashboard Cite

show abstract

“…When coal is exposed to ScCO 2 , the ScCO 2 is incorporated into the coal and it rearranges the coal's structure [19]. It is generally agreed that ScCO 2 can change the pore morphology of coal irreversibly, including pore volume, pore size distribution, surface area, and pore connectivity [20,21]. Additionally, ScCO 2 is an organic solvent and can mobilize some of the organic matter in the coal.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Study on Changes in the Pore Structures and Gas Desorption Properties of Intact and Tectonic Coals after Supercritical CO2 Treatment: Implications for Coalbed Methane Recovery

Zou

et al. 2018

Energies

View full text Add to dashboard Cite

Tectonic coals in coal seams may affect the process of enhanced coalbed methane recovery with CO2 sequestration (CO2-ECBM). The main objective of this study was to investigate the differences between supercritical CO2 (ScCO2) and intact and tectonic coals to determine how the ScCO2 changes the coal’s properties. More specifically, the changes in the tectonic coal’s pore structures and its gas desorption behavior were of particular interest. In this work, mercury intrusion porosimetry, N2 (77 K) adsorption, and methane desorption experiments were used to identify the difference in pore structures and gas desorption properties between and intact and tectonic coals after ScCO2 treatment. The experimental results indicate that the total pore volume, specific surface area, and pore connectivity of tectonic coal increased more than intact coal after ScCO2 treatment, indicating that ScCO2 had the greatest influence on the pore structure of the tectonic coal. Additionally, ScCO2 treatment enhanced the diffusivity of tectonic coal more than that of intact coal. This verified the pore structure experimental results. A simplified illustration of the methane migration before and after ScCO2 treatment was proposed to analyze the influence of ScCO2 on the tectonic coal reservoir’s CBM. Hence, the results of this study may provide new insights into CO2-ECBM in tectonic coal reservoirs.

show abstract

“…CO 2 injected into coal beds enhances coal bed methane (CBM), taking advantage of competitive adsorption. CO 2 geological storage-enhanced coal bed methane recovery (CO 2 -ECBM) is a new technology that has been proposed to implement CO 2 storage in coal beds and also enhance the recovery of CBM [2,3]. However, the injection capacity and storage potential of CO 2 in coal beds will decrease as a result of coal swelling deformation [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Coal Swelling Deformation Caused by Carbon Dioxide Adsorption Based on X-Ray Computed Tomography

et al. 2018

View full text Add to dashboard Cite

The geologic sequestration of carbon dioxide by coal beds leads to the swelling deformation of coal. In order to investigate the swelling deformation characteristics at the microscopic scale, X-ray computed tomography (CT) scanning technology was used. X-ray CT scanning technology detects the internal structure, deformation, and porosity of coal at different gas pressures. Results show that swelling deformation is nonuniform, which is caused by the heterogeneity of the coal structure. Through quantitative measurement of the distance between fractures and pseudocolor processing of CT images, we observed that fractures gradually close with the increase of adsorption pressure. As adsorption pressure increases, the porosity of coal decreases, and the density of coal increases.

show abstract

Changes in Pore Structure of Coal Associated with Sc-CO2 Extraction during CO2-ECBM

Cited by 28 publications

References 19 publications

Influences of supercritical carbon dioxide fluid on pore morphology of various rank coals: A review

Influences of supercritical carbon dioxide fluid on pore morphology of various rank coals: A review

Laboratory Study on Changes in the Pore Structures and Gas Desorption Properties of Intact and Tectonic Coals after Supercritical CO2 Treatment: Implications for Coalbed Methane Recovery

Analysis of Coal Swelling Deformation Caused by Carbon Dioxide Adsorption Based on X-Ray Computed Tomography

Contact Info

Product

Resources

About