Chemical Analysis and Electrochemical Monitoring of Extremely Low-Concentration Corrosive Impurity MgOHCl in Molten MgCl2–KCl–NaCl

MgCl 2 –KCl–NaCl is a promising thermal energy storage (TES) material and heat transfer fluid (HTF) with high operating temperatures of >700°C for next-generation concentrating solar power (CSP) plants. One major challenge future implementation the molten chloride TES/HTF technology arises from presence some corrosive impurities, especially MgOHCl, hydrolysis product hydrated . Even extremely low-concentration MgOHCl (tens ppm O in weight) can cause unneglectable corrosion commercial Fe–Cr–Ni alloys, which limits their service time as structural materials system. Thus, chemical analysis monitoring techniques at tens level are vital control. In this work, technique based on direct titration high-precision automatic titrator was developed an exact measurement level. It shows standard deviation below 5 average error 7 when concentration 36 O. Moreover, compared to other methods available literature reports, it exclude influence co-existing MgO measurement. This used calibrate previously electrochemical method cyclic voltammetry (CV) achieve reliable situ salt low The limitation <39 two work could be develop control system ensure long CSP