Steam hydration was planned to reactivate the spent synthetic cement-supported Ca-sorbents pelletized by mechanical granulator which possessed excellent performance. The effect of steam hydration on the reactivity of sorbents was investigated in a bubbling fluidized reactor. A specially designed impact apparatus was employed to evaluate the strength of reactivated pellets. The transitions of microstructure after hydration were also analyzed. The results showed that the reactivity of synthetic pellets was elevated significantly by steam hydration. The conversion of CaO for pellets increased from 0.113 to 0.419 after hydration in comparison with the raw limestone from 0.089 to 0.278

while the mechanical strength of synthetic pellets declined severely after reactivation. Large cracks emerged on hydrated limestone

which increased the reactivity and impaired the strength. Similar appearance was not observed on hydrated synthetic pellets

except improved porosity and expended surface which could enhance CO2 capacity and decline the strength. Superheating allowed the annealing of stacking faults and mechanical strain formed by hydration was proven to be able to improve the strength of hydrated pellets. Thus

the technology combining steam hydration with superheating can reactivate the spent synthetic sorbents without obvious strength decay.