Dynamic Corrosion of Carbonate Salt for 3rd Generation CSP Plants

Abstract

Eutectic ternary carbonate salt is one of the candidates for 3rd generation concentrated solar power (CSP) plants. Gen3 CSP targets higher operation temperatures, which strengthens the corrosivity issues associated to molten salts. Although there are corrosion studies for this carbonate salt in static conditions, the effect of salt flow is not fully understood. In this work, corrosion experiments under static and dynamic conditions are compared for SS310 subjected to ternary carbonate salt at 600ºC.
 The corrosion layer formed during static and dynamic tests were completely characterized by means of SEM-EDX and XRD (surface and cross-section). The corrosion products deposited in the salt during the experiment were analyzed by ICP-OES.
 The tests performed under dynamic conditions demonstrated an increase spallation of the corrosion layer. This spallation produced a thinner scale and exposed the Cr containing phase to the molten salt, fostering its dissolution. These results confirmed the significant effect of dynamic conditions on the corrosivity of eutectic ternary carbonate salt and the importance of assessing them in the design of 3rd generation CSP plants.