solar; fuels; thermogravimeter; heat and mass transfer; kinetics; solar radiation; thermochemistry; thermochemical cycle; concentrated solar radiation
Ackermann Simon, Takacs Michael, Scheffe Jonathan, Steinfeld Aldo, Reticulated porous ceria undergoing thermochemical reduction with high-flux irradiation, in International Journal of Heat and Mass Transfer
Takacs Michael, Ackermann Simon, Bonk Alexander, Neises M, Haueter Philipp, Scheffe Jonathan, Vogt Ulrich, Steinfeld Aldo, Splitting CO2 with a ceria-based redox cycle in a solar-driven thermogravimetric analyzer, in AIChE Journal
This proposal outlines the motivation for constructing a solar thermogravimetric system (Solar-TG) necessary for identifying reaction mechanisms and determining kinetic rate laws of high-temperature endothermic reactions driven by concentrated solar radiation. The need for a Solar-TG stems from fundamental research in high-temperature solar chemistry being performed by the Professorship of Renewable Carriers (PRE) at ETH Zurich. This research group works in close collaboration with PSI’s Solar Technology Laboratory and renowned international research institutes (Caltech, U. Colorado, U. Minnesota, Sandia Labs, DLR, CIEMAT, CNRS-Odeillo, and others). These projects are directed towards the efficient production of solar fuels and materials. Examples are thermochemical cycles with metal oxides redox reactions for splitting H2O and CO2, the carbothermal reduction of metal oxides for extracting metals (e.g. Al, Si), and the gasification of carbonaceous materials for producing syngas and liquid fuels. A major challenge in the solar reactor design and optimization for maximum solar-to-fuel energy conversion efficiency is matching the radiative heat transfer to the chemical reaction kinetics. For accomplishing that, it is important to acquire fundamental understanding of the reaction mechanisms and determine overall kinetic rate laws under the similar heat and mass transfer characteristics existing in highly concentrating solar systems, such as solar towers and solar parabolic dishes. The proposed Solar-TG should deliver the information needed by allowing temporal monitoring of the reaction with reactants directly exposed to concentrated solar radiation. Temperatures up to 3000 K and heating rates exceeding 1000 K/s can be achieved with reactants exposed to solar concentration ratios equivalent to 5000 suns. The proposed Sol-TG offers the offers the additional advantage of being able to operate at vacuum pressures. Coupled with gas chromatography and pyrometric temperature measurements, the mechanisms of high-temperature solar thermochemical processes can be examined in-depth. The significance of this research lies in the advancement of the thermo-sciences and engineering directed at developing solar chemical technologies, which have the potential of making significant contributions to sustainable, clean, and efficient energy utilization.