Thermal stability and corrosion characteristic analysis of low melting point ternary molten salt for thermal energy storage

Abstract

Molten salt is used as an important heat transfer and storage medium in thermal energy storage application. Thermal stability as well as corrosion characteristic are important for system safe operation. In this paper, a low melting point ternary hybrid salt was prepared and subjected to 1000h of constant temperature experiments and 1000h of static corrosion experiments on 304 at a high temperature of 600 °C. The results show that the low melting point mixed salt has a melting point of 143.1 °C, an initial crystal point of 136.1 °C, a decomposition temperature of 666.8 °C, and an average specific heat and thermal conductivity of 1.45 J g⁻¹k⁻¹ and 0.34 W m⁻¹K⁻¹. After a constant temperature of 1000 h at 600 °C, the melting point and initial crystal point have increased by 38 % and 49 %, the decomposition temperature has decreased by 8 %, and the specific heat and thermal conductivity have increased by 0.7 % and 0.3 %, respectively, compared with the base salt. 0.3 %. The weight loss per unit volume after 1000h of static corrosion was 6.2 mg cm⁻² and the annual corrosion rate was 0.068 mm y⁻¹.