(346c) Evaluating the Performances of Reduction Process in the Solar Thermochemical Two-Step CO2 Splitting Based on Ceria Redox Reactions

Authors: 
The emission of carbon dioxide is a severe problem in the current society. There are tremendous technologies that provide approaches to address the surplus CO2. Solar thermochemical reactor provides an attractive approach that utilizes the most common solar radiation as the thermal driving force to motivate the reaction between CO2 and metal oxides, which is so called metal oxide redox pair based thermochemical cycles. By two-step redox process, the incoming CO2 can be transformed to CO for further applications. Among the diversified metal oxide redox pairs, CeO2/CeO2-δ shows an anticipated performance, due to its fast redox kinetics, high crystallographic stability of a wide range of reacting oxygen non-stoichiometry, and relatively high oxygen solid-state conductivity.

In this work, a numerical analysis is applied to study on the performance of CeO2 reduction process in a segment of cavity-receiver reactor. The CeO2 is presented as catalyst particles in the domain to mimic the structure of porous medium. A three-dimension transient model is applied to simulate the momentum, heat, and mass transfer in the domain. CeO2 particle size, void fraction of domain, purge gas velocity and radiation flux rate are four key parameters that are analyzed in this work. By investigating on the influences of each factor to the reduction reaction, an optimized reaction rate can be achieved, which is beneficial to improve the solar to fuel efficiency of the reactor.