Calcium looping is a developing CO2 capture technology. It is based on the reversible
carbonation of CaO sorbent, which becomes less reactive upon cycling. One method of
increasing the reactivity of unreactive sorbent is by hydration in the calcined (CaO) form.
Here, sorbent has been subjected to repeated cycles of carbonation and calcination within a
small fluidised bed reactor. Cycle numbers of 0 (i.e., one calcination), 2, 6 and 13 have been
studied to generate sorbents that have been deactivated to different extents. Subsequently,
the sorbent generated was subjected to steam hydration tests within a thermogravimetric
analyser, using hydration temperatures of 473, 573 and 673 K. Sorbents that had been
cycled less prior to hydration hydrated rapidly. However, the more cycled sorbents exhibited
behaviour where the hydration conversion tended towards an asymptotic value, which is likely
to be associated with pore blockage. This asymptotic value tended to be lower at higher
hydration temperatures; however, the maximum rate of hydration was found to increase with
increasing hydration temperature. A shrinking core model has been developed and applied to
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the data. It fits data from experiments that did not exhibit extensive pore blockage well, but
fits data from experiments that exhibited pore blockage less well