Study of carbonation of CaO for high temperature thermal energy storage

In view of its potential application to high temperature heat energy storage, carbonation of CaO with various CO2 pressures is investigated in the temperature range 873-1173 K by using a thermogravimetric analyzer under atmospheric conditions. For a given temperature, although the reaction takes place for a partial pressure of CO2, P, higher than the equilibrium CO2 pressure of CaCO3, P-e, the reaction rate shows a slight increase with increasing P, On the other hand, for a given P, the rate increases rapidly with increasing temperature from 973 to 1023 K, above which it decreases gradually. By applying a grain model and assuming the presence of a reaction intermediate, a possible reaction rate equation has been developed.