Development of porous solid reactant for thermal-energy storage and temperature upgrade using carbonation/decarbonation reaction

Cyclic reaction performances of solid reactants for a CaO-CO2 chemical heat-pump designed for upgrading and storing high-temperature thermal energy were studied. Solid reactants composed of CaO as the reactant and CaTiO3 as the inert framework were prepared using the conventional powder method or the metal alkoxide method. Upon experiments of cyclic operation between CaO carbonation and CaCO3 decarbonation at 1023K, the reaction reversibility of the solid reactants with the inert CaTiO3 framework was steady, whereas that of the solid reactant without the inert framework decreased with sintering of the solid particles during cyclic operation. Reaction rates for the first carbonation and the decarbonation of solid reactant prepared using the alkoxide method were about 1.8 and 2.4 times faster, respectively, than for those prepared by the powder method due to the smaller average diameter of reactant particles derived from the alkoxide method.