Project Name: Sensing and Arresting Metal Corrosion in Molten Chloride Salts at 800^oC
Funding Opportunity: Solar Energy Technologies Office Fiscal Year 2018 Funding Program (SETO FY2018)
SETO Team: Concentrating Solar Power
Location: Tucson, AZ
SETO Award Amount: $800,000
Awardee Cost Share: $200,000
Planned Timeline: 2019-2021

-- Award and cost share amounts are subject to change pending negotiations --

Molten chloride salts are currently being investigated to transfer and store the heat generated by next-generation concentrating solar-thermal power (CSP) plants, and at high temperatures, they have the potential to rapidly corrode their containers and pipes, typically made of metal alloys. Corrosion is minimal when molten chloride salts are free of oxidizing impurities such as oxygen, water, and metal ions, but when they contain impurities, corrosion rates greatly increase. This project is investigating novel methods to remove oxidizing impurities in molten salts and limit corrosion, thereby reducing operation costs.

APPROACH

The project team is testing three ways to prevent corrosion to CSP components from oxidizing impurities in an operating CSP system. This first is using a zirconium screen to react with and remove the oxidizing impurities. The second is putting electrodes in the molten salt stream to remove oxidizing impurities through electrochemical reactions. And the third is applying an electric current to metal pipes and containers and inserting a highly active piece of metal called a sacrificial anode into the molten salt so the impurities react with and consume the anode, preserving the plant’s pipes and containers.  

INNOVATION

This project aims to develop several procedures to remove corrosive oxidizing impurities from molten salts and test the promising ones in a realistic molten salt flow environment. If successful, this team could help eliminate corrosion in CSP plants that use chloride salts, and help achieve next-generation cost targets of $0.05 per kilowatt-hour.