Accurate hydrodynamic models for the prediction of tracer diffusivities in supercritical carbon dioxide

“…Great effort has been devoted to creating expressions valid for predicting their diffusion in supercritical fluids, and the literature is rich in empirical models for their prediction. They can be commonly classified in two groups: models constructed on the base of rough hard sphere principles [ 21 , 22 , 23 ] and hydrodynamic models based on the Stokes–Einstein equation [ 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. A big number of these models present some limitations, failing in their estimations of D for polar or asymmetric solutes, or cannot be applied over a wide range of temperatures and pressures, nor near the critical point.…”

Section: Resultsmentioning

confidence: 99%

Binary Diffusion Coefficients for Short Chain Alcohols in Supercritical Carbon Dioxide—Experimental and Predictive Correlations

2023

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Experimental binary diffusion coefficients for short-chain alcohols in supercritical carbon dioxide were measured using the Taylor dispersion technique in a temperature range of 306.15 K to 331.15 K and along the 10.5 MPa isobar. The obtained diffusion coefficients were in the order of 10−8 m2 s−1. The dependence of D on temperature and solvent density was examined together with the influence of molecular size. Some classic correlation models based on the hydrodynamic and free volume theory were used to estimate the diffusion coefficients in supercritical carbon dioxide. Predicted values were generally overestimated in comparison with experimental ones and correlations were shown to be valid only in high-density regions.

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“…Thus, it is of great importance to research and understand the supercritical behavior of fluids and their heat transfer processes. Literature can provide a few theoretical and empirical correlative models capable to predict diffusion coefficients, e.g., hydrodynamicbased models [14][15][16][17][18][19], but there is still insufficient information, namely, experimental data for a given system that can allow to accurately calculate the diffusion coefficient values, as it is the case of certain carbon mixtures, or the models fail in certain temperature and pressure conditions. The availability of accurate diffusion coefficients is key to validly mimic real geological conditions, becoming essential information to design and optimize any process involving supercritical CO 2 , namely, to model the migration behavior inside the reservoirs but also, to complement with other properties (solubility, vapor-liquid equilibrium, etc.)…”

Section: Introductionmentioning

confidence: 99%

FTIR as a Powerful Tool for Measurements of Diffusion in Supercritical Carbon Dioxide Using Taylor Dispersion Method

et al. 2022

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A new experimental high-pressure setup for measuring diffusion coefficients in supercritical fluids, based on Taylor dispersion method, and using an FTIR detector to operate up to 25.0 MPa was designed and optimized. Tracer diffusivities, D12, of toluene and benzene in supercritical carbon dioxide were measured in the temperature range of 306.15–320.15 K, and pressure range of 7.5–17 MPa to evaluate the setup and experimental protocol. The effects of flow velocity, volume of the cell, absorbance at different wavenumbers on the diffusion coefficient as well as all parameters respecting the Taylor dispersion method have been analyzed. The obtained diffusion coefficients are in excellent agreement with the available literature data. The dependence of D12 on temperature, pressure, and solvent density were examined. Some correlation models based on the hydrodynamic theory were used to estimate the diffusion coefficients in supercritical carbon dioxide, which is the best agreement obtained for an improved version of the Wilke–Chang model.

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Accurate hydrodynamic models for the prediction of tracer diffusivities in supercritical carbon dioxide

Cited by 15 publications

References 137 publications

Molecular dynamics simulation of diffusion coefficients and structural properties of ketones in supercritical CO2 at infinite dilution

Molecular dynamics simulation of diffusion coefficients and structural properties of ketones in supercritical CO2 at infinite dilution

Binary Diffusion Coefficients for Short Chain Alcohols in Supercritical Carbon Dioxide—Experimental and Predictive Correlations

FTIR as a Powerful Tool for Measurements of Diffusion in Supercritical Carbon Dioxide Using Taylor Dispersion Method

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