On the study of the vapor-liquid interface of associating fluids with classical density functional theory

Vergara, Edgar L. Camacho; Kontogeorgis, Georgios M.

doi:10.1016/j.fluid.2020.112744

Cited by 7 publications

(4 citation statements)

References 93 publications

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“…In this context, classical density-functional theory (DFT) − has been instrumental in complementing both molecular-simulation and experimental studies and in providing valuable insights concerning the behavior of inhomogeneous fluids. On the other hand, the statistical associating fluid theory (SAFT) , has been a very successful tool for predicting the thermodynamic properties of homogeneous fluids. , There is a growing interest in SAFT-DFT − as well as 2D-SAFT − approaches to study inhomogeneous fluids. In these approaches, traditionally, fluid–solid interactions are accounted for using simplified coarse-grained (CG) representations; the (atomistic) details of the solid are not incorporated explicitly but, instead, are accounted for in an effective manner.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Molecular Simulation Study of Carbon Dioxide Sequestration into Dry and Wet Calcite Pores Containing Methane

et al. 2021

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We perform grand canonical Monte Carlo (GCMC) simulations to study the adsorption of carbon dioxide in a calcite slit pore. The injection of carbon dioxide is simulated by increasing the chemical potential of carbon dioxide, which allows for an investigation of adsorption under varying carbon dioxide loadings. The study is carried out for three different environments: an empty pore; a pore containing methane; and a pore containing methane with trace amounts of water. We systematically investigate the impact of the presence of these other fluids on carbon dioxide adsorption. We study the influence of carbon dioxide loading on fluid density in the pore and examine individual fluid-density profiles (in the direction normal to the fluid−solid interface). The order of fluid adsorption affinity to the surface is found to be water > carbon dioxide > methane. The interpretation of our results is informed by the examination of free-energy-averaged fluid−substrate potentials, which are computed independently from the simulations. Our observations suggest that ignoring the presence of water could lead to overestimation not only of methane availability but also of carbon dioxide storage capacity in pores, with important consequences in, for example, modeling carbon dioxide sequestration in calcite-rich reservoirs. Ultimately, it is hoped that the molecular-level insights from this study will aid the multiscale modeling of reservoir fluids in the context of enhanced oil recovery and carbon dioxide sequestration.

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Section: Introductionmentioning

confidence: 99%

Monte Carlo Molecular Simulation Study of Carbon Dioxide Sequestration into Dry and Wet Calcite Pores Containing Methane

et al. 2021

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“…The molecular parameters ε f f , σ f f , and m are the same as the ones used by the PC-SAFT equation of state listed in Table 2. The association contribution F assoc [ρ(r)] is determined by employing the associating weighed density approximation (aWDA) approach [35,36] to the PC-SAFT bulk free energy. The aWDA makes use of the same weighted density shown in Equation ( 9), and F assoc [ρ(r)] is:…”

Section: Pc-saftmentioning

confidence: 99%

“…where X[ρ(r)] is the fraction of non-bonded species at r relative to other water molecules [36,37], and has the following relationship with the average density ρ(r) determined by Equation ( 9) as,…”

Section: Pc-saftmentioning

confidence: 99%

Water Vapor Adsorption on Desiccant Materials for Rotary Desiccant Air Conditioning Systems

Zhu

Zhang

2023

Processes

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In order to determine the water vapor adsorption performance of a rotary desiccant-based air conditioning system, the behavior of water adsorption on cylindrical pores of different sizes was studied by using classical density functional theory (CDFT) based on perturbated chain statistical associating fluid theory (PC-SAFT). Firstly, the structural parameters of the desiccant material were characterized by scanning electron microscopy (SEM), X-ray Energy Dispersive Spectrum (EDS), and N2 adsorption/desorption isotherms, as well as adsorption equilibrium measurements of water vapor at temperature range 293–308 K. Secondly, the potential energy equation of water molecules in cylindrical pores was determined, and contribution of various terms of PC-SAFT for simulating fluid in cylindrical pores were established. Finally, the pore size distribution (PSD) of the desiccant materials is determined by the PC-SAFT kernel. Moreover, water vapor condensation was investigated with the PC-SAFT model in micropores. The results indicate that the rotary desiccant materials have a large number of micropores with a volume of 0.3669 cm3/g and the amount of water adsorption is about 0.285 g/g. The condensation pressure and the pore width corresponding to the saturated pressure P0 grow with an increase in the temperature, signifying that adjusting the PSD of the material has a significant effect on improving the dehumidification performance. The research concludes that the PSD range of the oxide cylindrical pore between 1.09 and 1.53 nm is particularly beneficial for dehumidification. This study provides valuable theoretical guidance for optimizing dehumidification materials.

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“…To be consistent with the equation of state, a molecular-based approach is required. Notable studies in which equation of state parameters of associating components are fitted to vapor pressures, liquid densities, and surface tensions have been presented by Fu and Wu, by Gloor et al and, more recently, by Camacho Vergara et al for a number of associating components, including water and linear alcohols.…”

Section: Introductionmentioning

confidence: 99%

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

Rehner

Groß

2020

J. Chem. Eng. Data

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With predictive methods, such as classical density functional theory and predictive density gradient theory (pDGT), it is possible to model bulk phase properties and interfacial tensions using the same model. For nonassociating fluids, these models can be used to predict interfacial properties for systems that lack experimental data. For associating components, however, predictions often show large deviations to experiments, which is at least partially rooted in highly correlated pure component parameters. Therefore, we use interfacial properties for discriminating pure component parameters by amending the PCP-SAFT parameter estimation for water and alcohols by including surface tension data in the objective function. To obtain a comprehensive comparison between different association models, a multiobjective optimization is performed. By analyzing the resulting pareto fronts, it is shown that including a fitted dipole moment improves the results for water but not for alcohols. The result of the multiobjective optimization is inconclusive about the optimal choice of association scheme for water as the preferred model changes along the pareto front. For small alcohols, in contrast to chemical intuition, the 4C association scheme gives the best results. For longer alcohols, the pareto analysis shows the limits of the homosegmented modeling approach.

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On the study of the vapor-liquid interface of associating fluids with classical density functional theory

Cited by 7 publications

References 93 publications

Monte Carlo Molecular Simulation Study of Carbon Dioxide Sequestration into Dry and Wet Calcite Pores Containing Methane

Monte Carlo Molecular Simulation Study of Carbon Dioxide Sequestration into Dry and Wet Calcite Pores Containing Methane

Water Vapor Adsorption on Desiccant Materials for Rotary Desiccant Air Conditioning Systems

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

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