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Keywords:

  • energy;
  • fuels;
  • reactor analysis;
  • surface chemistry/physics

Abstract

A two-step solar thermochemical cycle for splitting CO2 with Zn/ZnO redox reactions is considered, consisting of: (1) the endothermic dissociation of ZnO with concentrated solar radiation as the heat source and (2) the non-solar, exothermic, reduction of CO2 to CO by oxidizing Zn to ZnO; the latter is recycled to the first step. The second step of the cycle is investigated using a packed-bed reactor where micron-sized Zn particles were immobilized in mixtures with submicron-sized ZnO particles. Experimental runs were performed for Zn mass fractions in the range 67–100 wt % and CO2 concentration in the range 25–100%, yielding Zn-to-ZnO conversions up to 71% because of sintering prevention, as corroborated by SEM analysis. © 2010 American Institute of Chemical Engineers AIChE J, 2011