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Title: Interplay between structure and transport properties of molten salt mixtures of ZnCl 2–NaCl–KCl: A molecular dynamics study

In this paper, molten mixtures of network-forming covalently bonded ZnCl 2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl 2–NaCl–KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl 2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. Finally, this new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Arizona, Tucson, AZ (United States). Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
EE0005942
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 144; Journal Issue: 9; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Arizona, Tucson, AZ (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 14 SOLAR ENERGY; thermal conductivity; associated liquids; chemical elements; Eyring equation; concentrated solar power; molecular dynamics; phonons; transport properties; thermodynamic properties; thermodynamic states and processes
OSTI Identifier:
1470074
Alternate Identifier(s):
OSTI ID: 1239855

Manga, Venkateswara Rao, Swinteck, Nichlas, Bringuier, Stefan, Lucas, Pierre, Deymier, Pierre, and Muralidharan, Krishna. Interplay between structure and transport properties of molten salt mixtures of ZnCl2–NaCl–KCl: A molecular dynamics study. United States: N. p., Web. doi:10.1063/1.4942588.
Manga, Venkateswara Rao, Swinteck, Nichlas, Bringuier, Stefan, Lucas, Pierre, Deymier, Pierre, & Muralidharan, Krishna. Interplay between structure and transport properties of molten salt mixtures of ZnCl2–NaCl–KCl: A molecular dynamics study. United States. doi:10.1063/1.4942588.
Manga, Venkateswara Rao, Swinteck, Nichlas, Bringuier, Stefan, Lucas, Pierre, Deymier, Pierre, and Muralidharan, Krishna. 2016. "Interplay between structure and transport properties of molten salt mixtures of ZnCl2–NaCl–KCl: A molecular dynamics study". United States. doi:10.1063/1.4942588. https://www.osti.gov/servlets/purl/1470074.
@article{osti_1470074,
title = {Interplay between structure and transport properties of molten salt mixtures of ZnCl2–NaCl–KCl: A molecular dynamics study},
author = {Manga, Venkateswara Rao and Swinteck, Nichlas and Bringuier, Stefan and Lucas, Pierre and Deymier, Pierre and Muralidharan, Krishna},
abstractNote = {In this paper, molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2–NaCl–KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. Finally, this new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.},
doi = {10.1063/1.4942588},
journal = {Journal of Chemical Physics},
number = 9,
volume = 144,
place = {United States},
year = {2016},
month = {3}
}

Works referenced in this record:

Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides
journal, September 1976