The calcium looping cycle is being developed as a method for capturing CO2 from both flue and fuel gases. It works by using CaO as a CO2 carrier and through repeated cycles of carbonation and calcination can extract CO2 from a gas with a lower partial pressure of CO2 (e.g., exhaust stream from a power station) and provide a pure stream of CO2 suitable for sequestration. A key problem in the development of calcium looping technology is the decrease in reactivity of the sorbent with an increasing number of cycles of carbonation and calcination. The hydration of calcined sorbent has been shown to be a promising way of periodically regenerating the sorbent, so that its reactivity can be recovered, reducing the requirement to purge material from the cycle. In previous work, the reactivity of sorbents after hydration has been mainly studied by thermogravimetric analysis or in a fluidized bed with an unrealistically low calcination temperature. For this work, a laboratory-scale reactor capable of operation under...