Phase Diagram Analysis and Experimental Study of Low Melting Point Molten Salt for Large Scale Thermal Energy Storage

The eutectic properties of molten salts are crucial for thermal energy storage and serve as a key indicator for evaluating their application potential in thermal energy conversion, offering broad prospects for utilization. Eutectic properties are vital for assessing molten salts in thermal energy storage. This study employs Factsage software to thermodynamic simulate the eutectic behavior of LiNO3, NaNO3, KNO3, and NaNO2, aiming to rapidly predict eutectic formation, ratios, and minimum melting points. The influence of cation and anion combinations on these properties is investigated. Results indicate that different ionic compositions significantly affect the eutectic temperature and composition. To validate the phase diagram predictions, experimental verification was conducted on the NaNO3-KNO3-LiNO3 ternary system. The measured melting point and eutectic composition align closely with the simulated results, confirming the accuracy of the Factsage software. Through this series of studies, this paper not only provides new insights and methodologies for evaluating the eutectic properties of mixed nitrates but also offers crucial theoretical support for the future optimization and application of molten salt thermal energy storage technologies.