Diffusion of hydrocarbons diluted in supercritical carbon dioxide

Abstract Mutual diffusion of six hydrocarbons (methane, ethane, isobutane, benzene, toluene or naphthalene) diluted in supercritical carbon dioxide ( $${\hbox {CO}}_{2}$$ CO 2 ) is studied by molecular dynamics simulation near the Widom line, i.e., in the temperature range from 290 to 345 K along th...

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Main Authors: Denis Saric, Gabriela Guevara-Carrion, Yury Gaponenko, Valentina Shevtsova, Jadran Vrabec
Format: Article
Language:English
Published: Nature Portfolio 2023-09-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-023-42892-7
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author Denis Saric
Gabriela Guevara-Carrion
Yury Gaponenko
Valentina Shevtsova
Jadran Vrabec
author_facet Denis Saric
Gabriela Guevara-Carrion
Yury Gaponenko
Valentina Shevtsova
Jadran Vrabec
author_sort Denis Saric
collection DOAJ
description Abstract Mutual diffusion of six hydrocarbons (methane, ethane, isobutane, benzene, toluene or naphthalene) diluted in supercritical carbon dioxide ( $${\hbox {CO}}_{2}$$ CO 2 ) is studied by molecular dynamics simulation near the Widom line, i.e., in the temperature range from 290 to 345 K along the isobar 9 MPa. The $${\hbox {CO}}_{2}$$ CO 2  + aromatics mixtures are additionally sampled at 10 and 12 MPa and an experimental database with Fick diffusion coefficient data for those systems is provided. Taylor dispersion experiments of $${\hbox {CO}}_{2}$$ CO 2 with benzene, toluene, n-dodecane and 1,2,3,4-tetrahydronaphthalene are conducted along the $$p =$$ p =  10 MPa isobar. Maxwell–Stefan and Fick diffusion coefficients are analyzed, together with the thermodynamic factor that relates them. It is found that the peculiar behavior of the Fick diffusion coefficient of some $${\hbox {CO}}_{2}$$ CO 2 mixtures in the extended critical region is a consequence of the thermodynamic factor minimum due to pronounced clustering on the molecular scale. Further, the strong dependence of the Fick diffusion coefficient on the molecular mass of the solute as well as the breakdown of the Stokes–Einstein relation near the Widom line are confirmed. Eleven correlations for the prediction of the Fick diffusion coefficient of $${\hbox {CO}}_{2}$$ CO 2 mixtures are assessed. An alternative two-step approach for the prediction of the infinite dilution Fick diffusion coefficient of supercritical $${\hbox {CO}}_{2}$$ CO 2 mixtures is proposed. It requires only the state point in terms of temperature and pressure (or density) as well as the molecular solute mass as input parameters. First, entropy scaling is applied to estimate the self-diffusion coefficient of $${\hbox {CO}}_{2}$$ CO 2 . Subsequently, this coefficient is used to determine the infinite dilution Fick diffusion coefficient of the mixture, based on the finding that these two diffusion coefficients exhibit a linear relationship, where the slope depends only on the molecular solute mass.
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spelling doaj.art-9904bad15a95450b98d2fca451b29e672023-11-26T13:06:04ZengNature PortfolioScientific Reports2045-23222023-09-0113111610.1038/s41598-023-42892-7Diffusion of hydrocarbons diluted in supercritical carbon dioxideDenis Saric0Gabriela Guevara-Carrion1Yury Gaponenko2Valentina Shevtsova3Jadran Vrabec4Thermodynamics, Technical University of BerlinThermodynamics, Technical University of BerlinMRC, CP-165/62, Université libre de Bruxelles (ULB)Fluid Mechanics Group, Faculty of Engineering, Mondragon UniversityThermodynamics, Technical University of BerlinAbstract Mutual diffusion of six hydrocarbons (methane, ethane, isobutane, benzene, toluene or naphthalene) diluted in supercritical carbon dioxide ( $${\hbox {CO}}_{2}$$ CO 2 ) is studied by molecular dynamics simulation near the Widom line, i.e., in the temperature range from 290 to 345 K along the isobar 9 MPa. The $${\hbox {CO}}_{2}$$ CO 2  + aromatics mixtures are additionally sampled at 10 and 12 MPa and an experimental database with Fick diffusion coefficient data for those systems is provided. Taylor dispersion experiments of $${\hbox {CO}}_{2}$$ CO 2 with benzene, toluene, n-dodecane and 1,2,3,4-tetrahydronaphthalene are conducted along the $$p =$$ p =  10 MPa isobar. Maxwell–Stefan and Fick diffusion coefficients are analyzed, together with the thermodynamic factor that relates them. It is found that the peculiar behavior of the Fick diffusion coefficient of some $${\hbox {CO}}_{2}$$ CO 2 mixtures in the extended critical region is a consequence of the thermodynamic factor minimum due to pronounced clustering on the molecular scale. Further, the strong dependence of the Fick diffusion coefficient on the molecular mass of the solute as well as the breakdown of the Stokes–Einstein relation near the Widom line are confirmed. Eleven correlations for the prediction of the Fick diffusion coefficient of $${\hbox {CO}}_{2}$$ CO 2 mixtures are assessed. An alternative two-step approach for the prediction of the infinite dilution Fick diffusion coefficient of supercritical $${\hbox {CO}}_{2}$$ CO 2 mixtures is proposed. It requires only the state point in terms of temperature and pressure (or density) as well as the molecular solute mass as input parameters. First, entropy scaling is applied to estimate the self-diffusion coefficient of $${\hbox {CO}}_{2}$$ CO 2 . Subsequently, this coefficient is used to determine the infinite dilution Fick diffusion coefficient of the mixture, based on the finding that these two diffusion coefficients exhibit a linear relationship, where the slope depends only on the molecular solute mass.https://doi.org/10.1038/s41598-023-42892-7
spellingShingle Denis Saric
Gabriela Guevara-Carrion
Yury Gaponenko
Valentina Shevtsova
Jadran Vrabec
Diffusion of hydrocarbons diluted in supercritical carbon dioxide
Scientific Reports
title Diffusion of hydrocarbons diluted in supercritical carbon dioxide
title_full Diffusion of hydrocarbons diluted in supercritical carbon dioxide
title_fullStr Diffusion of hydrocarbons diluted in supercritical carbon dioxide
title_full_unstemmed Diffusion of hydrocarbons diluted in supercritical carbon dioxide
title_short Diffusion of hydrocarbons diluted in supercritical carbon dioxide
title_sort diffusion of hydrocarbons diluted in supercritical carbon dioxide
url https://doi.org/10.1038/s41598-023-42892-7
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AT valentinashevtsova diffusionofhydrocarbonsdilutedinsupercriticalcarbondioxide
AT jadranvrabec diffusionofhydrocarbonsdilutedinsupercriticalcarbondioxide