The Effect of Long-term Corrosion on a Molten Salt Pump in Contact with a Ternary Mixture in a CSP Plant

Abstract

Solar thermal plants commonly plan their operation for a period of approximately 25 years. Therefore, it is key to accurately predict and evaluate the damage and faults occurring for that long period. Among all components, we find that choosing the heat storage medium (molten salt) and the material (steel) used in the equipment and pipping plays a crucial role in the plant’s design. We tested the long-term corrosion effect of the molten salt pump in a low-melting-point ternary mixture composed of 30wt.%LiNO3+57wt.%KNO3+13wt.%NaNO3 over a period of more than 5 years, corresponding to 30,000 hours of operation in a pilot experimental facility built at the University of Antofagasta (Chile).