A chloride-based molten-salt system that uses a ternary blend of MgCl2/KCl/NaCl is investigated to provide higher-temperature thermal energy storage capability than conventional nitrate salt-based systems. Despite their high thermal stability and operating temperature, molten chlorides present several challenges, including the design of internal liners to prevent the corrosion and thermal stress of alloy tank shells. This work discusses issues and potential solutions related to containment of molten chloride salt, specifically the optimization of the hot face refractory materials for use as internal liners. Three down-selected refractory materials were analyzed with respect to permeation of salt through the material as well as chemical stability during high temperature operation. Through the application of X-ray imaging and electron spectroscopy techniques, highly stable secondary surface phases in equilibrium with the molten salt were identified, as well as time-dependent changes in the salt composition itself.
Bibliographical noteFunding Information:
This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Subcontract ADJ-9-92133-01 under Prime Contract No. DE-AC36-08GO28308. Funding provided by DOE Office of Energy Efficiency and Renewable Energy (EERE) . The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. The authors gratefully acknowledge Ms. Thao Truong, Mr. Douglas DeVoto, and Mr. Joshua Major for their contributions.
The research leading to the X-ray CT results received funding from the Engineering & Physical Sciences Research Council (EPSRC) via grants EP/P009050/1 and EP/M028100/1 . P. R. S. acknowledges the support of the Royal Academy of Engineering ( CIET 1718/59 ).
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- Corrosion science
- Gen3 CSP
- Molten chloride salt
- Refractory ceramics
- Surface passivation
- Thermal energy storage
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films