| Description |
Molten salts, particularly nitrates and nitrites, have been used in concentrated solar power (CSP) plants as a heat transfer fluid (HTF) since the early 1980s. One of the main issues associated with the use of molten salts is their decomposition at high temperatures. Currently, there is no technology available for the continuous monitoring of the composition of these salts. This study focuses on the research and development of an online oxide ion sensor that would provide CSP plant operators with live data. The formation of an oxide ion is an indication of the decomposition of nitrate and nitrite salts. Electrochemical methods like cyclic voltammetry (CV), linear square voltammetry (LSV), and square wave voltammetry (SWV) were used to measure changes in the O2- concentration in both HITEC and Solar Salt. The peak current values measured with LSV and SWV were correlated via a linear function to the oxide ion concentration. Multiple calibration curves were developed for both salts in bench scale electrochemical experiments. A variety of electrochemical test methods and test materials were investigated in this project to support the development of a real-time sensor for oxide ions in molten nitrate salts. Platinum coated titanium rods were used as the working (WE) and counter electrodes (CE). A Ag/AgNO3 electrode contained inside of a thin-walled mullite tube served as a reference electrode. The probe designed and assembled based on this study performed effectively to measure the change in oxide concentrations. |
