Experimental study on migration and heat transfer characteristics of three potential molten salts leaking into tank foundation materials

The leakage of molten salt tanks has attracted great attention in molten salt tower concentrating solar power plants. The current research on the leakage characteristics of molten salt mainly focuses on Solar Salt, and there is no report on the leakage characteristics of molten salt with great application potential, which is crucial to the design of molten salt tanks and their foundations in the future. In addition, there is no unified explanation for the morphological characteristics of the agglomerates formed after the molten salt leakage. In this paper, the migration and heat transfer characteristics of three potential molten salts (60–10-20–20 wt% KNO 3 -NaNO 3 -LiNO 3 -Ca(NO 3 ) 2 .4H 2 O, 7.5–23.9–68.6 wt% NaCl–KCl-ZnCl 2 , 32.1–33.4–34.5 wt% Li 2 CO 3 –Na 2 CO 3 –K 2 CO 3 ) leaking into the thermal tank foundation material are experimentally studied and compared with Solar Salt. The results indicate that both the operating temperature and molten salt type significantly affect the temperature rising rate of tank foundation and migration characteristics of molten salt. Increasing the operating temperature, the average temperature rising rate, maximum migration depth, maximum migration width and migration speed respectively increase, increase, decrease and increase. Compared with Solar Salt, the maximum migration depths of the three potential molten salts increase 56.3%, -11.6%, and -50.2%, and the maximum migration widths increase -22.7%, -16.7% and -2.7%, respectively. In addition, a model explaining the solidification and agglomeration of the molten salt is proposed and well verified by the experimental results.