Prediction of gas adsorption in 5a zeolites using Monte Carlo simulation

In this work we propose a new force field for modelling of adsorption of CO2, N2, O2 and Ar in all silica and Na+ exchanged Si–Al zeolites. The force field has a standard molecular-mechanical functional form with electrostatic and Lennard-Jones interactions satisfying Lorentz–Berthelot mixing rules and thus has a potential for further extension in terms of new molecular types. The parameters for the zeolite framework atom types are optimized by an iterative procedure minimizing the difference with experimental adsorption data for a number of different zeolite structures and Si:Al ratios. The new force field shows a good agreement with available experimental data including those not used in the optimization procedure, and which also shows a reasonable transferability within different zeolite topologies. We suggest a potential usage in screening of different zeolite structures for carbon capture and storage process, and more generally, for separation of other gases.

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“…Argon is modelled as a single spherical atom site with zero charge and Lennard-Jones parameters taken from [44].…”

Section: Models For Guest Moleculesmentioning

confidence: 99%

Transferable force-field for modelling of CO₂, N₂, O₂and Ar in all silica and Na⁺exchanged zeolites

Vujić

Lyubartsev

2016

Modelling Simul. Mater. Sci. Eng.

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“…Therefore, two a-cages are needed along all three crystallographic axes to form one repeating unit. Taking into account the intracrystalline water, which fills the channels and cavities of zeolites under ambient conditions, the formula of one pseudo-unit-cell is M 12 ]·x H 2 O. The number x of intracrystalline water molecules per pseudo-unit-cell depends on the cation M + .…”

Section: Zeolite Amentioning

confidence: 99%

“…Smit showed that this technique can be used in the grand canonical ensemble. [11] Among the many host-guest systems investigated using the GCMC or the configurational-bias GCMC technique are argon, oxygen, and nitrogen in 5A zeolites, [12] xenon, methane, p-and m-xylene in zeolite Na-Y, [13] alkanes from methane through pentane in AlPO-5, [14] benzene and pxylene in silicalite, [15] linear and branched alkanes in silicalite zeolite, [16] and benzene, cyclohexane, and hexane in AlPO-5.…”

Section: Introductionmentioning

confidence: 99%

Particle Distribution in a Microporous Material: Theoretical Concept

2005

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Particle distribution and exchange equilibria in a microporous host material, built up of equivalent particle sites, which are grouped in larger subsets, are described. Simplified descriptions evolve from the exact formulae in the thermodynamic limit. We find that, for example, a single zeolite A nanocrystal consisting of about 1000 pseudo-unit-cells fixes a lower limit for the use of the approximate formula describing particle distribution. A rational selectivity coefficient, which is approximately constant over the whole exchange range, only results if a single zeolite crystal consists of one million pseudo-unit-cells or more, or if a sufficiently large number of smaller crystals is considered. On the basis of the statistical particle distribution model, a closed, simple formula for the ion-exchange isotherm is then derived, which is valid for systems involving a variable number of coupled-exchange reactions. Its similarity to the Langmuir isotherm is discussed. The theory on ion-exchange equilibria is used to derive formulae for the change of free-energy, enthalpy, and entropy occurring in coupled ion-exchange reactions. The findings, though applicable to virtually any particle exchanging system with the structural properties described above, are applied to zeolite A, since this material can be treated as a nearly ideal model. The results derived can straightforwardly be used to evaluate experimental data quantitatively, since the common inequivalence of the host sites can be taken into account.

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“…According to accepted theories on physical adsorption (Brunauer-Emmett-Teller, or BET, and its precursors and evolutions, see for example Rouquerol et al 2013), the adsorbed gas gets confined, by the Lennard-Jones potential (Mortimer, 2000), in layers within few • A of the surfaces of the sorbent particles. Numerical simulations in Razmus and Hall (1991) show that the adsorbate's density markedly peaks in the adsorption layers with respect to the surrounding fluid phase; the contribution of those layers to the volume of the porous particles is negligible, which holds even more for chemisorption, in which case the adsorbate is confined within a single layer (Dabrowski, 2001). That is, the mass increment of particles due to adsorption can be regarded as a density increase only, at least at the pressure (within one order of magnitude of 1 bar) at which CO 2 adsorption takes place (Murata et al, 2002).…”

Section: Selective Replacement Methodsmentioning

confidence: 99%

Selective strategy for solid sorbent replacement in CCS

Colantuono

Cockerill

2017

Chemical Engineering Research and Design

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Please cite this article as: Giuseppe Colantuono, Timothy Cockerill, Selective strategy for solid sorbent replacement in CCS, (2017), http://dx.doi.org/10. 1016/j.cherd.2017.01.030 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Page 1 of 21A c c e p t e d M a n u s c r i p tThe continuous replacement of solid sorbent in post-combustion CCS loops is modeled. The known method removes/replaces a constant amount of sorbent after each iteration. Known method discards fresher material, too, as the looping sorbent is fully mixed. We can sort removed CO2-loaded sorbent: the fresher is denser due to higher capacity. Our novel strategy puts freshest sorbent back; we compute the reduced need of sorbent. *Research HighlightsPage 2 of 21 AbstractAn innovative method for sorbent replacement in the looping of a generic solid sorbent for post-combustion carbon capture and sequestration (CCS) is introduced. First, the standard replacement method is revisited with some original results presented. A new strategy is then modeled, aimed at selectively replacing the material as it degrades. This method exploits the density difference, after adsorption, between relatively fresh, CO 2 -laden sorbent and relatively degraded material, with small residual adsorption capacity. The model is then applied to values of degradation rate within the experimental range available in scientific literature for silica-supported amines (SSA). The selective removal strategy ideally allows a saving of 37% of the sorbent with respect to the standard, undifferentiated replacement considered in first place, while keeping the same adsorptive capacity of the system.

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Prediction of gas adsorption in 5a zeolites using Monte Carlo simulation

Cited by 139 publications

References 15 publications

Transferable force-field for modelling of CO₂, N₂, O₂and Ar in all silica and Na⁺exchanged zeolites

Transferable force-field for modelling of CO₂, N₂, O₂and Ar in all silica and Na⁺exchanged zeolites

Particle Distribution in a Microporous Material: Theoretical Concept

Selective strategy for solid sorbent replacement in CCS

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Prediction of gas adsorption in 5a zeolites using Monte Carlo simulation

Cited by 139 publications

References 15 publications

Transferable force-field for modelling of CO2, N2, O2and Ar in all silica and Na+exchanged zeolites

Transferable force-field for modelling of CO2, N2, O2and Ar in all silica and Na+exchanged zeolites

Particle Distribution in a Microporous Material: Theoretical Concept

Selective strategy for solid sorbent replacement in CCS

Contact Info

Product

Resources

About

Transferable force-field for modelling of CO₂, N₂, O₂and Ar in all silica and Na⁺exchanged zeolites

Transferable force-field for modelling of CO₂, N₂, O₂and Ar in all silica and Na⁺exchanged zeolites