Mobilisation of elements from coal due to batch reactor experiments with CO2 and water at 40°C and 9.5MPa

Dawson, G. K. W.; Golding, Suzanne D.; Biddle, Dean; Massarotto, P.

doi:10.1016/j.coal.2015.01.005

Cited by 32 publications

(16 citation statements)

References 27 publications

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“…In turn, the gas adsorption capacity of the coal is affected, which is a crucial mechanism in CO 2 ‐ECBM processes. So far, only a few researchers have conducted the related studies on supercritical CO 2 ‐H 2 O‐coal coexistent systems under in situ conditions . It is not enough for us to fully understand the supercritical CO 2 ‐H 2 O‐coal interaction processes.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

Zhao

Wang

et al. 2018

Greenhouse Gases

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An initial investigation into the impacts of CO2 storage in unmineable coal seams, with or without enhanced coal‐bed methane recovery (CO2‐ECBM), was conducted, focusing on changes in the chemical and physical properties of coal. A high metamorphic grade anthracite was obtained from Qinshui Basin in China. Powdered coal was reacted with deionized water and carbon dioxide at temperatures of 25–35 °C and pressures of 5–11 MPa, in seven custom‐built batch reactors – conditions similar to the in situ formation conditions for the coal samples. An experiment with N2 saturated‐water to compare CO2‐free‐water mobilization with CO2‐water was also performed. It was observed that the supercritical CO2‐H2O‐coal reaction had a more significant influence on the micropores than mesopores. The micropore increase was reflected directly in the specific surface area and pore volume, which increased sharply. The true density also increased accordingly. The changes to the pore structure in the coal may affect the storage capacity of CO2 and can modify the fluid flow pattern in the process of CO2‐ECBM. Meanwhile, after exposing the coal samples to supercritical CO2, most of the trace‐element content in the reaction solutions was very low; only the Se and Mn content was beyond acceptable drinking water quality, but not enough to produce a serious influence on shallow aquifers. Nonetheless, the potential for mobilizing toxic trace elements from the coalbed is an important factor to be considered when evaluating CO2 sequestration in deep unmineable coal seams. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

“…So far, only a few researchers have conducted the related studies on supercritical CO 2 -H 2 O-coal coexistent systems under in situ conditions. [40][41][42][43][44] It is not enough for us to fully understand the supercritical CO 2 -H 2 O-coal interaction processes.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

Zhao

Wang

et al. 2018

Greenhouse Gases

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“…Solvated electrons in ScCO 2 can dissolve some coal and cause the coal to swell (Dawson et al., 2015; Gathitu et al., 2009). Swelling decreased the interactions among the coal macromolecules, causing the extension and reorientation of the coal macromolecules, rupture of the hydrogen bonds, and rearrangement of coal chemical structure (Dawson et al., 2015; Gathitu et al., 2009). Swelling is accompanied by bond dissociation reactions, polyaddition reactions, and hydrogen bond interactions and is a general expression of above-mentioned chemical reactions.…”

Section: Resultsmentioning

confidence: 99%

“…The acidic solution can leach out inorganic minerals in coal, e.g. calcite, dolomite, magnesite, etc., which can change the pore-fracture structure and the connectivity of coal (Dawson et al, 2015;Liu et al, , 2010Massarotto et al, 2010;Wang et al, 2016aWang et al, , 2016b. Recent studies of interactions between a ScCO 2 -H 2 O system and coal have focused on that aspect.…”

Section: Introductionmentioning

confidence: 99%

The effects of CO₂ on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy

Liu

Sang

et al. 2018

Energy Exploration & Exploitation

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The interactions between supercritical CO 2 and coal and their effects on changes in the coal pore structure and organic groups play a critical role in the CO 2 geological storage-enhanced coalbed methane recovery. To investigate the effects of supercritical CO 2 on organic groups in coals of different ranks and its mechanisms under different temperature and pressure conditions, CO 2 sequestration processes in bituminous coals and high-rank coals were replicated using a highpressure reactor. Four coal samples of different ranks were exposed to supercritical CO 2 and water under three temperatures and pressures for 240 h. Fourier transform infrared spectroscopy was used to provide semiquantitative ratios and Fourier transform infrared spectra of coal samples before and after the supercritical CO 2-H 2 O treatment. The results show that interactions between supercritical CO 2 and coal were controlled by the coal macromolecular structure, and semianthracite is the inflection point of interaction characteristics for coal samples of different ranks. Bituminous coal, including high-and low-volatility bituminous coal, has a low degree of condensation of its aromatic structure, and its aromatic nuclei can facilitate addition reactions. Swellings primarily break cross-links between aromatic nuclei in the same aromatic layer. These characteristics favor the polymerization addition of aliphatic side chains of aromatic nuclei, causing an increase in the degree of condensation of the aromatic structures in bituminous coal. Highrank coals including semianthracite and anthracite have a high degree of condensation of their

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“…dissolution of minerals (Credoz et al., 2011; Hedges et al., 2007), transformation of clay minerals (Farquhar et al., 2015) and formation of new minerals (Liu et al., 2015). H 2 CO 3 has been found to leach out and dissolve some minerals in coals, especially, minerals filled in the pores and fractures, such as carbonate and aluminosilicate minerals (Black et al., 2015; Dawson et al., 2015). The dissolution of minerals has been observed to increase the pores and fractures of coals and generate pores in the minerals, which can increase the volume and connectivity of meso- and macropores (Chen et al., 2017; Liu et al., 2018).…”

Section: Mechanism 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

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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.

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Mobilisation of elements from coal due to batch reactor experiments with CO2 and water at 40°C and 9.5MPa

Cited by 32 publications

References 27 publications

Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

The effects of CO₂ on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy

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

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Mobilisation of elements from coal due to batch reactor experiments with CO2 and water at 40°C and 9.5MPa

Cited by 32 publications

References 27 publications

Experimental study of physical‐chemical properties modification of coal after CO2 sequestration in deep unmineable coal seams

Experimental study of physical‐chemical properties modification of coal after CO2 sequestration in deep unmineable coal seams

The effects of CO2 on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy

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

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Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

Experimental study of physical‐chemical properties modification of coal after CO₂ sequestration in deep unmineable coal seams

The effects of CO₂ on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy