Combined Ceria Reduction and Methane Reforming in a Solar-Driven Particle-Transport Reactor.

We report on the experimental performance of a solar aerosol reactor for carrying out the combined thermochemical reduction of CeO and reforming of CH using concentrated radiation as the source of process heat. The 2 kW solar reactor prototype utilizes a cavity receiver enclosing a vertical AlO tube which contains a downward gravity-driven particle flow of ceria particles, either co-current or counter-current to a CH flow. Experimentation under a peak radiative flux of 2264 suns yielded methane conversions up to 89% at 1300 °C for residence times under 1 s. The maximum extent of ceria reduction, given by the nonstoichiometry δ (CeO), was 0.25. The solar-to-fuel energy conversion efficiency reached 12%. The syngas produced had a H:CO molar ratio of 2, and its calorific value was solar-upgraded by 24% over that of the CH reformed.