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Papers by SUMANT PATANKAR
The Journal of Chemical Physics, 2020
Fundamental understanding of subcritical/supercritical behavior of key hydrocarbon species inside... more Fundamental understanding of subcritical/supercritical behavior of key hydrocarbon species inside nanoporous matrices at elevated pressure and temperature is less developed compared to bulk fluids, but this knowledge is of great importance for chemical and energy engineering industries. This study explores in detail the structure and dynamics of ethane (C2H6) fluid confined in silica nanopores, with a focus on the effects of pressure and different ratios of C2H6 and CO2 at non-ambient temperature. Quasielastic neutron scattering (QENS) experiments were carried out for the pure C2H6, C2H6:CO2=3:1, and 1:3 mixed fluids confined in 4-nm cylindrical silica pores at three different pressures (30, 65, and 100 bar) at 323 K. Two Lorentzian functions were required to fit the spectra, corresponding to fast and slow translational motions. No localized motions (rotations, vibrations) were detected. Higher pressures resulted in hindrances of the diffusivity of C2H6 molecules in all systems investigated. Pore size was found to be an important factor, i.e., dynamics of confined C2H6 is more restricted in smaller pores compared to the larger pores used in previous studies. Molecular dynamics (MD) simulations were performed to complement the QENS experiment at 65 bar, providing supportive structure information and comparable dynamic information. The simulations indicate CO2 molecules are more strongly attracted to the pore surface compared to C2H6. The C2H6 molecules interacting with or near the pore surface form a dense first layer (L1) close to the pore surface and a second less dense layer extending into the pore center (L2). Both the experiments and simulations revealed the role that CO2 molecules play in enhancing C2H6 diffusion ('molecular lubrication') at high CO2:C2H6 ratios. The energy scales of the two dynamic components, fast and slow, quantified by both techniques, are in very good agreement. Herein, the simulations identified the fast component as the main contributor to
The Journal of Physical Chemistry C, 2016
Ethane is found confined to mineral and organic pores in certain shale formations. Effects of con... more Ethane is found confined to mineral and organic pores in certain shale formations. Effects of confinement on structural and dynamic properties of ethane in mesoporous controlled pore glass (CPG) were studied by gravimetric adsorption and quasi-elastic neutron scattering (QENS) measurements. The obtained isotherms and scattering data complement each other by quantifying the relative strength of the solid–fluid interactions and the transport properties of the fluid under confinement, respectively. A magnetic suspension balance was used to measure the adsorption isotherms at two temperatures and over a range of pressures corresponding to a bulk density range of 0.01–0.35 g/cm3. Key confinement effects were highlighted through differences between isotherms for the two pore sizes. A comparison was made with previously published isotherms for CO2 on the same CPG materials. Behavior of ethane in the smaller pore size was probed further using quasi-elastic neutron scattering. By extracting the self-diffusivity an...
Chemical Physics Letters, 2016
Tous droits réservés © Association canadienne d'éducation de langue française, 2018 Ce document e... more Tous droits réservés © Association canadienne d'éducation de langue française, 2018 Ce document est protégé par la loi sur le droit d'auteur. L'utilisation des services d'Érudit (y compris la reproduction) est assujettie à sa politique d'utilisation que vous pouvez consulter en ligne. https://apropos.erudit.org/fr/usagers/politique-dutilisation/ Cet article est diffusé et préservé par Érudit. Érudit est un consortium interuniversitaire sans but lucratif composé de l'
The Journal of Chemical Physics, 2020
Fundamental understanding of subcritical/supercritical behavior of key hydrocarbon species inside... more Fundamental understanding of subcritical/supercritical behavior of key hydrocarbon species inside nanoporous matrices at elevated pressure and temperature is less developed compared to bulk fluids, but this knowledge is of great importance for chemical and energy engineering industries. This study explores in detail the structure and dynamics of ethane (C2H6) fluid confined in silica nanopores, with a focus on the effects of pressure and different ratios of C2H6 and CO2 at non-ambient temperature. Quasielastic neutron scattering (QENS) experiments were carried out for the pure C2H6, C2H6:CO2=3:1, and 1:3 mixed fluids confined in 4-nm cylindrical silica pores at three different pressures (30, 65, and 100 bar) at 323 K. Two Lorentzian functions were required to fit the spectra, corresponding to fast and slow translational motions. No localized motions (rotations, vibrations) were detected. Higher pressures resulted in hindrances of the diffusivity of C2H6 molecules in all systems investigated. Pore size was found to be an important factor, i.e., dynamics of confined C2H6 is more restricted in smaller pores compared to the larger pores used in previous studies. Molecular dynamics (MD) simulations were performed to complement the QENS experiment at 65 bar, providing supportive structure information and comparable dynamic information. The simulations indicate CO2 molecules are more strongly attracted to the pore surface compared to C2H6. The C2H6 molecules interacting with or near the pore surface form a dense first layer (L1) close to the pore surface and a second less dense layer extending into the pore center (L2). Both the experiments and simulations revealed the role that CO2 molecules play in enhancing C2H6 diffusion ('molecular lubrication') at high CO2:C2H6 ratios. The energy scales of the two dynamic components, fast and slow, quantified by both techniques, are in very good agreement. Herein, the simulations identified the fast component as the main contributor to
The Journal of Physical Chemistry C, 2016
Ethane is found confined to mineral and organic pores in certain shale formations. Effects of con... more Ethane is found confined to mineral and organic pores in certain shale formations. Effects of confinement on structural and dynamic properties of ethane in mesoporous controlled pore glass (CPG) were studied by gravimetric adsorption and quasi-elastic neutron scattering (QENS) measurements. The obtained isotherms and scattering data complement each other by quantifying the relative strength of the solid–fluid interactions and the transport properties of the fluid under confinement, respectively. A magnetic suspension balance was used to measure the adsorption isotherms at two temperatures and over a range of pressures corresponding to a bulk density range of 0.01–0.35 g/cm3. Key confinement effects were highlighted through differences between isotherms for the two pore sizes. A comparison was made with previously published isotherms for CO2 on the same CPG materials. Behavior of ethane in the smaller pore size was probed further using quasi-elastic neutron scattering. By extracting the self-diffusivity an...
Chemical Physics Letters, 2016
Tous droits réservés © Association canadienne d'éducation de langue française, 2018 Ce document e... more Tous droits réservés © Association canadienne d'éducation de langue française, 2018 Ce document est protégé par la loi sur le droit d'auteur. L'utilisation des services d'Érudit (y compris la reproduction) est assujettie à sa politique d'utilisation que vous pouvez consulter en ligne. https://apropos.erudit.org/fr/usagers/politique-dutilisation/ Cet article est diffusé et préservé par Érudit. Érudit est un consortium interuniversitaire sans but lucratif composé de l'