Dynamic corrosion test using LiNO3 containing molten salt for CSP applications

Abstract

Low melting point thermal energy storage (TES) materials have been proposed in the last years to reduce the storage cost in concentrating solar power (CSP) technology. One of the most interesting additive due to the enhancement in thermal properties is lithium nitrate. However, there is a lack of dynamic corrosion tests to simulate real operation conditions in CSP plants. In this work, we present a dynamic reactor set up where a mixture of 30 wt.% LiNO3 + 57 wt.% KNO3 + 13 wt.%. NaNO3 is moved through a mechanical stirrer obtaining a lineal speed of 0.30 m/s. A commercial carbon steel A516 was tested as container material at 390 °C during 1000 h. Fe2O3 and Fe3O4 were obtained as the main corrosion products by scanning electron microscopy (SEM) and x-ray diffraction (XRD) with a metallographic corrosion rate of 0.015 mm/year.