An accurate model for the filling pressure of carbon slit-like micropores

Malheiro, Carine; Mendiboure, Bruno; Plantier, Frédéric; Guatarbes, Bertrand; Miqueu, Christelle

doi:10.1016/j.fluid.2015.07.003

Cited by 6 publications

(4 citation statements)

References 24 publications

(38 reference statements)

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“…Accordingly, it is consistent with recent molecular simulation studies, for example, by Mosher et al using GCMC simulations, who reported the adsorbate layer density of CH 4 in gas shale and coal systems to increase with increasing bulk phase pressure. Malheiro et al also found a similarly increasing trend of the adsorbate phase density in their model for argon and nitrogen sorption in slit carbon micropores.…”

Section: Modeling Approachmentioning

confidence: 67%

Laboratory-Scale Investigation of Sorption Kinetics of Methane/Ethane Mixtures in Shale

Dasani

Wang

Tsotsis

et al. 2017

Ind. Eng. Chem. Res.

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Natural gas produced from shales is composed primarily of methane (CH 4 ), accounting for up to 87−96 mol %. In addition to CH 4 , shale gas contains a host of secondary components, including nitrogen (N 2 ), helium (He), and hydrocarbons such as ethane (C 2 H 6 ) and propane (C 3 H 8 ). CH 4 and the other hydrocarbons are thought to be stored in the adsorbed state in the micropores and mesopores of the shale, and as free gas in the (natural) fracture networks. Although convective transport and diffusive transport account for the short-term behavior during shale gas production, desorption is thought to dominate the long-term dynamics of shale gas production. The key objective of this study, therefore, is to investigate the sorption kinetics of methane/ethane mixtures in gas shales. Specifically, we study here the adsorption/ desorption behavior of pure CH 4 and C 2 H 6 , and their mixtures in a whole shale sample (cube) using thermogravimetric analysis (TGA). The choice of ethane is because it is, typically, the second largest component of shale gas and is thought to compete for the same adsorption sites as methane. To this end, we first determine the steady-state isotherms of the pure component gases and their binary mixtures, which are essential to predicting the gas storage capacity of the shale. We then study the dynamics toward equilibrium during the sorption process in order to better understand the role of desorption during the later times of shale gas production. We apply the well-established Langmuir approach to analyze and interpret the experimental dynamic sorption observations. Our experimental data predict a lag in ethane production relative to that of methane due to the preferential sorption of ethane on the shale. This provides for added insight into interpreting field-scale production data in terms of the produced gas compositions. The experimental observations and their analysis pave, therefore, a path toward improving the interpretation of production data from shale gas operations via an enhanced understanding of desorption dynamics (and subsequent mass transfer) of gas mixtures in shale.

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Section: Modeling Approachmentioning

confidence: 67%

Laboratory-Scale Investigation of Sorption Kinetics of Methane/Ethane Mixtures in Shale

Dasani

Wang

Tsotsis

et al. 2017

Ind. Eng. Chem. Res.

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“…In order to have a relevant comparison between experimental and modeling adsorption isotherms, one needs first to get the Pore Size Distribution (PSD) of the material. In a previous work, 56 we have developed a new thermodynamic model in the same spirit of Horwath and Kawazoe approach 57 in order to link the filling pressure of a micropore to its size and thus obtain the PSD of a microporous carbon adsorbent from a low temperature adsorption isotherm (Nitrogen or Argon, classically). Here, we have performed the adsorption isotherm with nitrogen at 77.4 K on Carboxen 1012 with a Micromeretics gas porosimeter (ASAP 2020) ( Figure 5) and then applied our model to get its PSD that is shown in Figure 6.…”

Section: Characterization Of the Microporous Adsorbentmentioning

confidence: 99%

Density functional theory for the description of spherical non-associating monomers in confined media using the SAFT-VR equation of state and weighted density approximations

Malheiro

Mendiboure

Plantier

et al. 2014

The Journal of Chemical Physics

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As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.

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“…The specific surface area and distribution of pore size were performed by JW-BK300, Beijing Jingwei Gao Bo Science and Technology Co., LTD. For this equipment, the application pore size range is from 0.35 to 40 nm by (HK mode for micropore analysis). [38,39]…”

Section: Methodsmentioning

confidence: 99%

Growing Intact Membrane by Tuning Carbon Down to Ultrasmall 0.37 nm Microporous Structure for Confining Dissolution of Polysulfides Toward High‐Performance Sodium–Sulfur Batteries

Liu

Zhang

et al. 2023

Energy & Environ Materials

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Room temperature sodium–sulfur (Na–S) batteries are severely hampered by dissolution of polysulfides into electrolytes. Herein, a facile approach is used to tune a biomass‐derived carbon down to an ultrasmall 0.37 nm microporous structure for the first time as a cathode in sodium–sulfur batteries. This produced an intact uniform Na2S membrane to greatly confine the dissolution of polysulfides while realizing a direct solid phase conversion for complete reduction of sulfur to Na2S, which delivers a sulfur loading of 1 mg cm−2 (50 wt.%), an excellent rate capacity (933 mAh g−1 @ 0.1 A g−1 and 410 mAh g−1 @ 2 A g−1), long cycle performance (0.036% per cycle decay at 1 A g−1 after 1500 cycles), and a high energy density for 373 Wh kg−1 (0.1 A g−1) based on whole electrode weight (active sulfur loading + carbon), ranking the best among all reported plain carbon cathode‐based room temperature sodium–sulfur batteries in terms of the cycle life and rate capacity. It is proposed that the solid Na2S produced in the ultrasmall pores (0.37 nm) can be squeezed out to grow an intact membrane on the electrode surface covering the outlet of the pores and greatly depressing the dissolution effect of polysulfides for the long cycle life. This work provides a green chemistry to recycle wastes for sustainable energies and sheds light on design of a unique pore structure to effectively block the dissolution of polysulfides for high‐performance sodium–sulfur batteries.

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An accurate model for the filling pressure of carbon slit-like micropores

Cited by 6 publications

References 24 publications

Laboratory-Scale Investigation of Sorption Kinetics of Methane/Ethane Mixtures in Shale

Laboratory-Scale Investigation of Sorption Kinetics of Methane/Ethane Mixtures in Shale

Density functional theory for the description of spherical non-associating monomers in confined media using the SAFT-VR equation of state and weighted density approximations

Growing Intact Membrane by Tuning Carbon Down to Ultrasmall 0.37 nm Microporous Structure for Confining Dissolution of Polysulfides Toward High‐Performance Sodium–Sulfur Batteries

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