Development of new low melting point mixed molten salt heat storage material

doi:10.19799/j.cnki.2095-4239.2020.0204

Abstract

Abstract:

As a heat storage medium, nitrate molten salt has the advantage of high use temperature, good heat transfer performance, and large specific heat capacity. The development of a new low-melting point mixed molten salt heat storage material can solve the problems of low energy storage efficiency and pipeline freezing and blocking in binary solar salt. This study accurately predicts that the composition of the ternary eutectic point and the experimental results are basically consistent with the theoretical results based on the CALPHAD method and the results from PANDAT for the phase diagram of the NaNO₃-NaNO₂-KNO₂ ternary system. We add LiNO₃ on the basis of the ternary eutectic point composition ratio and prepare NaNO₃-KNO₂-NaNO₂-LiNO₃ quaternary molten salt. The quaternary low-melting point molten salt composition ratio is obtained through experimental optimization screening, resulting to 21.57% NaNO₃, 41.27% KNO₂, 17.16% NaNO₂, and 20% LiNO₃. The melting point of the low-melting molten salt is 84.2 °C, as obtained from the DSC test. The upper limit of temperature usage is 583.3 °C by the TG test. The step cooling curve test shows a solid-liquid phase transition temperature of 78.9 °C. The results show that the low-melting point molten salt can be widely used as a heat storage and heat transfer medium in CSP and industrial heat storage, among others.

Key words: molten salt, heat storage material, thermal properties

CLC Number:

TK 514

Haihua LUO, Qiang SHEN, Junguang LIN, Yanmei ZHANG, Yunke XU. Development of new low melting point mixed molten salt heat storage material[J]. Energy Storage Science and Technology, 2020, 9(6): 1755-1759.

Figures/Tables 6

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