Development of SiC-SiC Heat Exchangers for High Temperature Heat Transfer

Industrial process heat is used for a large variety of applications with different heat requirements and with temperature ranges covering a wide spectrum. Process temperatures range from 100 to 180°C for district heating and desalination to over 800°C for coal gasification and hydrogen production. Although Concentrated Solar Power (CSP) systems can potentially provide much of the process heat needs, nuclear power systems are the best choice to minimize carbon release. Gen IV nuclear reactor technologies have advanced safety features could limit the size of low-population zones to the actual plant site boundary minimizing monitoring and evacuation planning that may discourage industrial users to locate adjacent to the power plants. The high operating temperatures of the Gen IV designs also make them able to support most industrial thermal processes.Yet, even when the industrial facilities are closer to the power plants, heat transfer can be difficult for high temperature processes. Reliable, high-temperature, SiC composite heat exchangers are important contributors to IES feasibility. High-temperature heat transfer between power plants and co-located industrial facilities requires coolants like molten salts with high boiling temperatures and very low vapor pressures. While less reactive than most liquid metals, molten salts are very corrosive and are not compatible with many traditional metals, especially at very high temperatures. High nickel alloy such as Haynes 230, offer short-term corrosion resistance, but these materials are very expensive and creep strength drops rapidly at the desired temperatures.Alternative materials and associated fabrication techniques are needed. Novatech will develop and demonstrate the feasibility of utilizing silicon carbide composites to fabricate robust, resilient heat exchangers that will effectively and efficiently integrate industrial energy users with high-temperature nuclear power plants.The technology already demonstrated by NovaTech has shown that SiC fiber wound SiC tubes are significantly more robust than simple SiC tubes and will retain their strength at high temperature. SiC is also compatible with high temperature liquid metals and molten salts. For this project, we will build on our experience in the design of SiC composite components for nuclear reactors and solar thermal power plants.