Particle heat exchanger for the integration of CST into a supercritical CO2 Brayton power cycle

This work presents part of the main results of the project “Components’ and Materials’ Performance for Advances Solar Supercritical CO2 Powerplants” (COMPASsCO2). The project investigated key components required to integrate a solar tower concentrated solar thermal (CST) plant with a supercritical CO2 (sCO2) Brayton power cycle operating at extreme conditions of 700°C and 250 bars, aimed to achieve an outstanding thermal efficiency of 49%. One part of the project focused on the development and testing of new solid particles and their coatings for use as heat transfer and thermal storage materials. The project also investigated the development and testing of new chromium alloys to be used as bulk material or Coatings for the application in a particle/sCO2 heat exchanger (HEX) under extreme conditions. The HEX design was optimized to increase the heat transfer coefficient between particles and sCO2. Furthermore, a pilot particle/sCO2 HEX was manufactured and tested, and advanced computer models were used to assess the durability of the components. The knowledge gained from this project is not only applicable to this use case, but can contribute to the decarbonization of industrial applications under harsh conditions.