Revisiting methane absolute adsorption in organic nanopores from molecular simulation and Ono-Kondo lattice model

Pang, Wanying; Jin, Zhehui

doi:10.1016/j.fuel.2018.07.098

Cited by 33 publications

(64 citation statements)

References 78 publications

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“…52 The capability of the model highlighted in this study is the incorporation of pore size distributions, making it suitable for understanding adsorption on clay minerals characterized by both micro-and mesoporosity. The LDFT model has also compared well with the grand canonical Monte Carlo (GCMC) simulations, 50,57,58 showing its reliability and efficiency with less computation time.…”

Section: Modeling Ldft Model For Supercritical Adsorptionmentioning

confidence: 99%

Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals

Hwang

Pini

2019

Environ. Sci. Technol.

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Clay minerals abound in sedimentary formations and the interaction of reservoir gases with their sub-micron features has direct relevance to many geo-energy applications. The quantification of gas uptake over a broad range of pressures is key towards assessing the significance of these physical interactions on enhancing storage capacity and gas recovery. We report a systematic investigation of the sorption properties of three source clay minerals-Na-rich montmorillonite (SWy-2), illite-smectite mixed layer (ISCz-1), and illite (IMt-2)-using CO 2 and CH 4 up to 30 MPa at 25 to 115 • C. The textural characterization of the clays by gas physisorption indicates that micropores are only partly accessible to N 2 (77 K) and Ar (87 K), while larger uptakes are measured with CO 2 (273 K) in the presence of illite. The supercritical excess sorption experiments confirm these findings, while revealing differences in uptake capacities that originate from the clay-specific pore size distribution. The Lattice Density Functional Theory (LDFT) model describes accurately the measured sorption isotherms by using a distribution of properly weighted slit pores and clay-specific solid-fluid interaction energies, which agree with isosteric heats of adsorption obtained experimentally. The model indicates that the maximum degree of pore occupancy is universal to the three 1 clays and the two gases, and it depends solely on temperature, reaching values near unity at the critical temperature. These observations greatly support the model's predictive capability for estimating gas adsorption on clay-bearing rocks and sediments.

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Section: Modeling Ldft Model For Supercritical Adsorptionmentioning

confidence: 99%

Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals

Hwang

Pini

2019

Environ. Sci. Technol.

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“…Recently, adsorption of supercritical fluids has attracted the interest of many research groups. − This interest stems from the various behaviors observed for supercritical fluids that are not manifested for subcritical fluids − as well as from the adsorbed gas in shale, which plays a key role in the accurate estimation of gas in place (GIP) and the prediction of well productivity. − Shale gas exists in three different phases within the shale formation: (i) as free compressed gas, (ii) as adsorbed fluid on the surface, and (iii) as a dissolved component in liquid hydrocarbon and brine. , The most widely used approach for estimating shale GIP is to sum these three components . As a result, the adsorbed gas in shale reservoir, which behaves differently from free gas, may contribute 20–85% of the total shale gas content. − Therefore, accurate estimation of the adsorption gas content in shale gas resources is of great significance for the calculation of GIP and the resource composition. − …”

Section: Introductionmentioning

confidence: 99%

“…There have been numerous experimental works to study the gas adsorption behavior in shale media. ,,− Among them, gravimetric and volumetric methods have been widely used to measure the Gibbs adsorption of various hydrocarbon species. ,− However, neither the gravimetric method nor the volumetric method can measure the adsorbed phase volume; therefore, the measured amount of adsorption is the surface excess adsorption. − The surface excess adsorption represents the amount of gas exceeding bulk gas phase density in the system. The absolute adsorption represents the total amount of gas molecules in the sorbed state. − …”

Section: Introductionmentioning

confidence: 99%

Improved Methane Adsorption Model in Shale by Considering Variable Adsorbed Phase Density

Kong¹,

Fan²,

Xiao

et al. 2021

Energy Fuels

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Numerous models have been used to describe the isotherm adsorption of supercritical methane in porous media. Many models assume that the adsorbed phase density does not change with pressure during the adsorption process. However, recent studies show that this assumption is unreasonable, and the resulting error is enormous. Therefore, we propose an improved isotherm adsorption model in shale that assumes that the adsorbed phase density keeps changing and that adsorbed phase volume remains constant during the adsorption process [the variable density adsorption (VD) model]. A logarithmic function is used to describe the change of the adsorbed phase density during the adsorption process. The product of the adsorbed phase density and volume is used to calculate the adsorption capacity. The fitting results for large amounts of methane adsorption data show that this assumption is reasonable. The fitting results are consistent with the molecular simulation, and it will be more convenient to obtain the truly adsorbed phase volume and density. The adsorbed phase volume and density obtained by the VD model show a good positive correlation with the total organic carbon, specific surface area, and micropore volume, which indicates the rationality of adsorption parameters fitted by the model. As a result of the correct calculation of the adsorption phase density, the gas in place (GIP) obtained by the VD model is lower than the supercritical Dubinin–Radushkevich model. The new model proposed this time provides a new tool for the study of shale methane isotherm adsorption and a new model for the calculation of GIP. Using this model, the adsorbed phase density and volume of methane can be obtained more conveniently and accurately. This will be a milestone in the VD model.

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“…The Steele model represents a significant improvement over the (9-3) potentials for the molecular modelling of adsorption of gases on carbons [4][5][6][7][8][9][10][11][12][13][14][15][16]. The expression has been typically used in molecular simulation or in theoretical studies to model adsorption of gases on graphitic surfaces however, the expression is applicable to other crystalline solids with a hexagonal structure oriented on the basal plane or to face-centred cubic (fcc) crystals oriented on the (111) plane.…”

Section: Introductionmentioning

confidence: 99%

“…Forte [20] presented the equivalent (10-4) and (9-3) expressions for Mie force fields; the second one has been employed by Theodorakis et al [26,27] to simulate coarse-grained (CG) systems with non-bonded interactions modelled via Mie potentials with parameters obtained through the statistical associating fluid theory in its gamma version (SAFT-γ) [28,29]. Despite these isolated examples, the simple LJ-based (10-4), (9-3), and (10-4-3) expressions are ubiquitous [10][11][12][13][14][15][16][30][31][32][33][34][35][36]. The preference for these potentials can be attributed to the lack of detail required by many simulation studies, where the onus is on the effects of a generic external potential or wall (in which case the actual nature of the surface is irrelevant), the ready-to-use incorporation in simulation software, or simply because those are a well-known option ('better the devil you know from the devil you don't').…”

Section: Introductionmentioning

confidence: 99%

Extension of the effective solid-fluid Steele potential for Mie force fields

Jiménez-Serratos

Müller

2019

Molecular Physics

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Molecular simulation of fluid systems in the presence of surfaces require computationally expensive calculations due to the large number of solid-fluid pair interactions involved. Representing the explicit solid as a continuous wall with an effective potential can significantly reduce the computational time and allows exploring larger temporal and spatial scales. Different analytical expressions can be found in the literature depending on the structural characteristics of the solid and the approximations adopted in the derivation. The well-known (10-4-3) Steele potential is one such analytic expression that faithfully represents the effective solid-fluid interactions for homonuclear crystalline solids with hexagonal lattice symmetry. However, this and most of the effective potentials found in the literature have been developed for fluids and solids interacting exclusively through Lennard-Jones potentials. In this work, we extend the Steele model to obtain the effective wall-fluid potentials for Mie force fields. We perform molecular dynamics simulations of coarse-grained fluids modelled via the SAFT force field approach in the presence of explicit and implicit surfaces to compare structural and dynamic properties in both representations. Also, we study the adsorption of ethane into slit-like pores with explicit and implicit surfaces via grand canonical Monte Carlo simulations. We explore the validity and the improvement in the simulation performance as well as the limitations of the proposed expression.

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Revisiting methane absolute adsorption in organic nanopores from molecular simulation and Ono-Kondo lattice model

Cited by 33 publications

References 78 publications

Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals

Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals

Improved Methane Adsorption Model in Shale by Considering Variable Adsorbed Phase Density

Extension of the effective solid-fluid Steele potential for Mie force fields

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Revisiting methane absolute adsorption in organic nanopores from molecular simulation and Ono-Kondo lattice model

Cited by 33 publications

References 78 publications

Supercritical CO2 and CH4 Uptake by Illite-Smectite Clay Minerals

Supercritical CO2 and CH4 Uptake by Illite-Smectite Clay Minerals

Improved Methane Adsorption Model in Shale by Considering Variable Adsorbed Phase Density

Extension of the effective solid-fluid Steele potential for Mie force fields

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Product

Resources

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Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals

Supercritical CO₂ and CH₄ Uptake by Illite-Smectite Clay Minerals