10:30 AM - *SF15.12.01
Robust Ceramic/Metal Composites for High-Temperature Heat Exchangers for Concentrated Solar Power
Ken Sandhage1,Yujie Wang1,Camilla McCormack1,Priyatham Tumurugoti1,Alexander Strayer1,Adam Caldwell1,Thuan Nguyen1,Sunghwan Hwang1,Qingzi Zhu2,Mehdi Pishahang2,Asegun Henry2,Kevin Trumble1,Grigorios Itskos1,Mario Caccia1
Purdue University1,Massachusetts Institute of Technology2
Concentrated solar power (CSP) plants utilizing thermal energy storage could provide large-scale renewable and dispatchable electricity, with an associated significant reduction in greenhouse gas emissions, if such electricity production were to become cost competitive with fossil-fuel-based power plants. The solar thermal-to-electrical conversion efficiency of CSP plants may be appreciably increased, with a commensurate reduction in the levelized cost of CSP-derived electricity, by operating such power plants at higher temperatures. By increasing the turbine inlet temperature of the working fluid to >750oC and by using power cycles with high-pressure, supercritical carbon dioxide (sCO2) as the working fluid (instead of conventional Rankine cycles at <550oC with subcritical steam as the working fluid), the relative heat-to-electricity conversion efficiency may be increased by >20%. However, effective heat transfer to sCO2 at >750oC and >20 MPa requires compact heat exchangers capable of operating under such extreme conditions. The significant decrease in mechanical performance of conventional stainless steels and nickel-based superalloys at such high temperatures and pressures inhibits their use in such heat exchangers.
Co-continuous ceramic/metal composites can provide attractive combinations of properties for use in compact heat exchangers operating under extreme mechanical, thermal, and chemical conditions [1-4]. The interconnected ceramic phase can provide such composites with high-temperature stiffness and creep resistance, whereas the metallic phase can provide high-temperature ductility for enhanced resistance to fracture as well as enhanced high-temperature thermal conductivity. Ceramic and metallic phases in such composites can also exhibit desired thermal and chemical compatibility at high temperatures; that is, properly-selected ceramics and metals can possess similar thermal expansion coefficients (to allow for resistance to thermal cycling) and can retain a high solidus temperature with limited mutual solid solubility. The ceramic/metal composites may either be inherently resistant to high-temperature corrosion or corrosion-resistant coatings may be utilized. Dense co-continuous ceramic/metal composites can also be generated in desired geometries (e.g., thin plates with tailorable channel patterns) for compact heat exchangers via combined use of scalable, low-cost ceramic forming (e.g., tape casting, pressing) followed by shape-preserving reactive liquid metal infiltration (e.g., the patented Displacive Compensation of Porosity process ). The net-shape processing, microstructures, and attractive properties of several ceramic/metal composites (carbide/metal, oxide/metal) for use in advanced, high-temperature heat exchangers for CSP plants will be discussed.
 M. Caccia, M. Tabandeh-Khorshid, G. Itskos, A. R. Strayer, A. S. Caldwell, S. Pidaparti, S. Singnisai, A. D. Rohskopf, A. M. Schroeder, D. Jarrahbashi, T. Kang, S. Sahoo, N. R. Kadasala, A. Marquez-Rossy, M. H. Anderson, E. Lara-Curzio, D. Ranjan, A. Henry, K. H. Sandhage, “Ceramic–Metal Composites for Heat Exchangers in Concentrated Solar Power Plants,” Nature, 562 (7727) 406 (2018).
 Q. Zhu, X. Tan, B. Barari, M. Caccia, A. R. Strayer, M. Pishahang, K. H. Sandhage, A. Henry, “Design of a 2 MW ZrC/W-Based Molten-Salt-to-sCO2 PCHE for Concentrated Solar Power,” Applied Energy, 300, 117313 (2021).
 T. D. Nguyen, M. Caccia, C. K. McCormack, G. Itskos, K. H. Sandhage, “Corrosion of Al2O3/Cr and Ti2O3/Cr Composites in Flowing Air and CO2 at 750°C,” Corrosion Science, 179, 109115 (2021).
 T. D. Nguyen, G. D. Scofield, S. Hwang, M. D. Sangid, G. Itskos, M. Caccia, K. H. Sandhage, "Corrosion of a Dense, Co-Continuous, SiC/Si Composite in CO2 and Synthetic Air at 750oC," Journal of Materials Research and Technology, in press.