Water reactivation of spent sorbents from a calcium looping process.

The aim of this work was to investigate the hydration-reactivation behaviour of spent sorbents from a calcium looping process. The following aspects were considered: the changes in the sorbent physico-chemical properties induced by hydration, the regeneration of the CO2 capture capacity and the attrition tendency of the material once reused in the looping cycle. To this end, a reference limestone was subjected to multiple calcination/carbonation cycles in a lab-scale fluidized bed reactor and then reactivated by water hydration at room temperature for different times. Physico-chemical characterization of the hydrated material indicated that 10 min hydration was long enough to effectively reactivate the spent sorbent. Results of the tests showed a renewal of the CO2 capture capacity that could be related to chemical hydration and increase in sorbent porosity. Attrition/fragmentation data referring to both as-received and reactivated sorbent are presented and critically discussed.