Mitigation of Molten Salt Corrosion

Technical Report · Sat Apr 30 04:00:00 EDT 2022

DOI:https://doi.org/10.2172/1891879· OSTI ID:1891879

Sandhage, Kenneth H. ^[1]

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1. Purdue Univ., West Lafayette, IN (United States); Purdue University

The desire to increase the peak operational temperature of Concentrated Solar Power (CSP) plants to lower the levelized cost of CSP-derived electricity, has led to consideration of an earth-abundant, low-cost, thermally-stable, molten MgCl₂-KCl-NaCl (40-40-20 mole%) salt for high-temperature thermal energy storage and heat transfer. The reliable, long-term containment of such a molten salt is challenging, however, due to the corrosion of cost-effective, high-temperature structural metal alloys in this salt (particularly if this salt is contaminated with oxygen-bearing species). This project has been focused on: i) development of equipment for evaluating corrosion kinetics in molten chlorides under well-controlled thermal, fluid dynamic, and atmospheric conditions at CSP-relevant temperatures, ii) use of such equipment to evaluate the influence of forced convection on corrosion kinetics (to determine the role of liquid phase diffusion on such corrosion), and iii) identifying a corrosion-mitigation strategy that can be industrially applied to achieve a projected annual corrosion ≤30 μm at CSP-relevant temperatures. The overall goals of this project have been: i) to understand the rate-limiting step(s) and associated kinetic laws governing corrosion in molten chlorides at 750°C, ii) to determine key operational parameters affecting the corrosion kinetics in molten salts, and iii) to demonstrate the tailoring of such parameters to appreciably reduce such corrosion.

• Research Organization: Purdue University, West Lafayette, IN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: EE0008532
• OSTI ID: 1891879
• Report Number(s): DOE-Purdue-FTR-8532
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
Molten chloride salts
air-stable molten chloride salts
high-temperature corrosion
thermal energy storage