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

The CaO–CaCO 3 cycle offers a promising high-temperature CO 2 capture technology, but the decay in CO 2 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 °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 CO 2 capture capacity was observed to be negligible.