Syngas production by simultaneous splitting of H2O and CO2via ceria redox reactions in a high-temperature solar reactor

Abstract

Solar syngas production from H₂O and CO₂ is experimentally investigated using a two-step thermochemical cycle based on cerium oxide redox reactions. A solar cavity-receiver containing porous ceria felt is directly exposed to concentrated thermal radiation at a mean solar concentration ratio of 2865 suns. In the first endothermic step at 1800 K, ceria is thermally reduced to an oxygen deficient state. In the second exothermic step at 1100 K, syngas is produced by re-oxidizing ceria with a gas mixture of H₂O and CO₂. The syngas composition is experimentally determined as a function of the molar co-feeding ratio H₂O : CO₂ in the range of 0.8 to 7.7, yielding syngas with H₂ : CO molar ratios from 0.25 to 2.34. Ten consecutive H₂O/CO₂-splitting cycles performed over an 8 hour solar experimental run are presented.