Materials compatibility for the next generation of Concentrated Solar Power plants

Abstract

The next generation of Concentrated Solar Power (CSP) plants are expected to operate at higher temperatures than those currently in use, for improved efficiency and reduced cost of power generation. This paper, presents a proposed scheme for a CSP plant designed to operate at temperatures from 550 to 700 °C. With regard to the three main sections of the proposed plant including receiver, storage and power generator, a comprehensive review on degradation mechanisms that threaten structural alloys at elevated temperatures has been provided and the gaps in the literature identified. Thermal fatigue and creep were recognized as general threats to all sections of the system. In addition, specific degradation mechanisms caused by liquid sodium as the preferred heat transfer fluid material, eutectic salts or metals as Phase Change Material (PCM) in the storage and sCO2 Brayton cycle in the generator have been discussed in detail. For the purpose of studying compatibility, a list of candidate alloys, with acceptable mechanical strengths at 550 to 700 °C, has been developed together with some ideas for future research. Further research on the proposed list could result in the better understanding of the interaction between candidate structural materials and environmental conditions in the next generation of CSP plants.