Investigation of High-Temperature Steam Hydration of Naturally Derived Calcium Oxide for Improved Carbon Dioxide Capture Capacity over Multiple Cycles

The CaO-CaCO3 cycle offers a promising high-temperature CO2 capture technology, but the decay in CO2 absorption capacity of CaO over multiple cycles poses a challenge that needs to be overcome to make it an economically feasible process. Of the various methods suggested, intermediate hydration of CaO seems to be the most promising. Low-temperature hydration is known to produce a highly reactive sorbent; however, this will be detrimental for integration in the high-temperature process. Hence, high-temperature steam hydration is proposed, and the effect of such hydration has been investigated on CaO obtained from commercially available precursors. In this work, the hydration was performed at 500 degrees C in a fixed-bed reactor and thermogravimetry and Brunauer-Emmett-Teller (BET) techniques were used for sorbent analyses and characterization. Multiple cycles of carbonation-calcination-hydration were performed, and the reduction in the CO2 capture capacity was observed to be negligible.