Thermal diffusion in micropores by molecular dynamics computer simulations

Galliéro, Guillaume; Colombani, Jean; Bopp, P.; Duguay, B.; Caltagirone, Jean‐Paul; Montel, François

doi:10.1016/j.physa.2005.06.001

Cited by 31 publications

(17 citation statements)

References 23 publications

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“…-ground experiments (Croccolo et al 2012;Urteaga et al 2012;Giraudet et al 2014;Larrañaga et al 2015) on thermodiffusion in ternary mixtures that will take advantage of an extension of the theory of nonequilibrium fluctuations in ternary mixtures (Ortiz de Zárate et al 2014), -Molecular Dynamics (MD) simulations of thermodiffusion in multicomponent mixtures in bulk (Galliero et al 2003;Galliero et al 2009;Artola and Rousseau 2013) and confined situations (Galliero et al 2006;Hannaoui et al 2013), -developing models to take into account thermodiffusion when describing the initial state of a reservoir (Montel et al 2007;Touzet et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Impact of Thermodiffusion on the Initial Vertical Distribution of Species in Hydrocarbon Reservoirs

Galliéro

Bataller

Croccolo

et al. 2015

Microgravity Sci. Technol.

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In this work we propose a methodology, based on molecular dynamics simulations, to quantify the influence of segregation and thermodiffusion on the initial state distribution of the fluid species in hydrocarbon reservoirs. This convection-free approach has been applied to a synthetic oil composed of three normal alkanes and to a real acid gas. It has been found that the thermodiffusion effect induced by the geothermal gradient is similar (but opposite in sign) to that due to segregation for both mixtures. In addition, because of the combined effect of thermal expansion Guillaume Galliero guillaume.galliero@univ-pau.fr and thermodiffusion, it has been observed that the density gradient can be reversed, in the presence of a geothermal gradient. These numerical results emphasize the need of improving our quantification of thermodiffusion in multicomponent mixtures. The SCCO-SJ10 experiments will be a crucial step towards this goal.

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Section: Introductionmentioning

confidence: 99%

Impact of Thermodiffusion on the Initial Vertical Distribution of Species in Hydrocarbon Reservoirs

Galliéro

Bataller

Croccolo

et al. 2015

Microgravity Sci. Technol.

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“…In studying Thermodiffusion using Molecular Dynamics, several recent studies have employed the HEX algorithm to estimate thermodiffusive properties of different types of fluid mixtures including isotopes [79][80][81] and hydrocarbons [83][84][85]. However, there are several drawbacks of this HEX algorithm:…”

Section: Major Drawbacks Of the Current Heat Generation Algorithmmentioning

confidence: 99%

Molecular Dynamics Calculation Of Thermodiffusion Coefficients In Binary And Ternary Mixtures

Mozaffari¹

2021

Preprint

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Thermodiffusion phenomenon in fluid mixtures has been investigated by several scientists in theoretical as well as experimental fields for decades. Nevertheless, due to shortcomings of both methods, interest in searching for alternative approaches to shed some light on molecular scale of the phenomenon has spurred. The objective of this thesis is to develop an accurate molecular dynamics (MD) algorithm that can predict thermodiffusive separation in binary and ternary fluid mixtures. More importantly, the proposed algorithm should be computationally efficient in order to be suitable for integration into multi-scale computational models to simulate thermodiffusion in a large system such as an oil reservoir. In developing such an effective and efficient computational tool, this thesis introduces a modified heat exchange algorithms, wherein, a new mechanism is introduced to rescale velocities which curbs the energy loss in the system and at the same time minimizes the computational time. The performance of the new algorithm in studying Soret effect for binary and ternary mixtures has been compared with other non-equilibrium molecular dynamics (NEMD) models including regular heat exchange algorithm (HEX) and reverse non-equilibrium molecular dynamics (RNEMD). Different types of binary mixtures were studied including one equimolar mixture of argon (Ar)-krypton (Kr) above its triple point, non-equimolar normal alkane mixtures of hexane (nC6)-decane (nC10) as well as hexane (nC6)-dodecane (nC12) for six compositions, three non-equimolar mixtures of pentane (nC5) decane (nC10) at atmospheric temperature and pressure. Additionally, the new algorithm was validated for different ternary mixtures including ternary normal alkanes methane (nC1)-butane (nC4)- dodecane (nC12) for three compositions, and one composition of different types of alkane mixture of 1,2,3,4-tetrahydronaphthalene (THN)-dodecane (nC12)-sobutylbenzene (IBB). The new algorithm demonstrates a significant improvement in reducing the energy loss by nearly 32%. Additionally, the new algorithm is about 7-9% more computationally efficient than the regular HEX for medium and large systems. In terms of direction of thermodiffusive segregations in binary mixtures, in agreement with the experimental data, the new algorithm shows that the heavier component moves towards the cold region whereas the lighter component accumulates near the hot zone. Additionally, the strength of segregation process diminishes as the concentration of heavy component in the mixture increases. The new algorithm improved the prediction of thermodiffusion factor in binary mixtures by 24% in binary mixtures. With respect to the ternary mixtures, similarly to binary mixtures the heaviest and lightest component in the mixture move towards, cold and hot zones, respectively. While the intermediate component shows the least tendency to segregate. In terms of the strength of Soret effect, the new algorithm is about 17% more accurate than the regular HEX algorithm with respect to experimental data.

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“…46 The Lennard-Jones parameters are listed in Table 1. The solid phase parameters mimics a simplified silicate, 47 which represents the most abundant fraction of the inorganic matter in shales. 48 The solid is considered rigid during the grand canonical Monte Carlo simulations.…”

Section: ■ Molecular Simulationsmentioning

confidence: 99%

Theoretically Based Model for Competitive Adsorption of Subcritical Mixtures

Collell

Galliéro

2014

J. Phys. Chem. C

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International audienceNumerous works have been achieved on the prediction of subcritical fluids, but most of them are about gas adsorption at low pressures or low concentrations, where adsorption consists in the formation of one adsorption layer. However, at higher pressures or concentrations, these mixtures can form an important number of adsorbed fluid layers and may exhibit a gas/liquid transition when the capillary condensation pressure is reached. In this work, we derive from the statistical mechanics a model predicting subcritical mixtures in such conditions. In the proposed model, the adsorbed molecules are supposed to be distributed in two distinct adsorption layers. Two parameters per adsorbed species characterize the interactions of the species in the adsorption layers. One additional parameter characterizes the adsorption capacity of the porous structures. To check the consistency of the model, Monte Carlo simulations on pure compound and mixtures adsorption are used as reference data. Our model shows improvements compared to the Ideal Adsorbed Solution Theory, whose adsorption isotherm are modeled with the BET model developed by Gritti et al. [J. Chromatogr. A 2002, 978, 81-107]. Especially, the predictions of the adsorbed phases compositions are in good agreement with molecular simulation results, in both gas and liquid states. The adsorbed amount in the gas phase are also correctly predicted. By introducing an additional empirical parameter which characterizes the liquid adsorption capacity, it is also possible to predict the adsorbed amounts for the liquid phase, providing a consistent approach to model the adsorption of liquid and gas mixture

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Thermal diffusion in micropores by molecular dynamics computer simulations

Cited by 31 publications

References 23 publications

Impact of Thermodiffusion on the Initial Vertical Distribution of Species in Hydrocarbon Reservoirs

Impact of Thermodiffusion on the Initial Vertical Distribution of Species in Hydrocarbon Reservoirs

Molecular Dynamics Calculation Of Thermodiffusion Coefficients In Binary And Ternary Mixtures

Theoretically Based Model for Competitive Adsorption of Subcritical Mixtures

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