Investigation of Chloride Molten Salts for Thermal Energy Storage (TES) Applications

Concentrating Solar Power (CSP) plants represent the key solution for exploiting the solar energy and moving towards a more renewable world’s energy. Consequently, a Thermal Energy Storage (TES) system has to be employed for efficient utilization to overcome the seasonal fluctuations. Due to their high thermal and physiochemical properties, molten salt mixtures are potential candidates for TES and/or for Heat Transfer Fluids (HTF). In this report, the purity of molten salt is investigated in different procedures, due to its importance and high influence on the corrosion rate of structural alloys involved in every power plant. Most of halide salts are hygroscopic and thereby heating in presence of water stimulates hydrolysis of the salt followed by the formation of oxides/hydroxides compounds. Unacceptable results of salt degradation and corrosion rates are gained by simple heating experiments. Then, purification processes are performed inducing improved salt quality and thereby reduced corrosion rates. Ensuring high quality of salt’s purity is a significant step for an efficient exploitation of molten salts as a HTF and as storage media for solar or other industrial application in which molten salt is required.