Effect of the Carbonation Temperature on the CO2 Carrying Capacity of CaO

The calcium looping process based on the CaO/CaCO3 carbonation/calcination cycle has been proven to be an efficient CO2 capture technology. Most of the experimental work describing the behavior of the CaO particles has been performed under carbonation reference conditions of 650 degrees C and 10-15% vol CO2. Although, process schemes recently proposed have pointed out the practical benefits of operating the carbonator reactor at lower temperatures, on the assumption that these would lead to higher CO2 capture efficiencies. However, there is a lack of correlations for estimating the evolution of the carrying capacity along cycling at temperatures below 650 degrees C. Therefore, in this work the carrying capacity of a high purity natural Ca-material used as reference has been studied in a selected range of representative carbonation temperatures (450-725 degrees C). The parameters on the CaO deactivation curve that is widely employed have been readjusted to accord with a more general decay model that takes into account the effect of the carbonation temperature on the thickness of the CaCO3 product layer that marks the end of the fast kinetically controlled regime.