CaO based sorbents for CO2 capture are in demand because it can be used in many industrial process,such as zero emission power generation technologies [1],steam methane reforming processes for enhanced hydrogen production [2],and energy storage systems in chemical heat pumps [3].In these technologies,the CO2 sorbent is used repeatedly based on the reversibility of the reaction:CaO(s)+CO2(g) carbonation(→)(←)calaination CaCo3(s) (1)However,carbonation conversions rapidly decrease with increasing numbers of reaction cycles [4].Loss-in-capacity is mainly owing to the sintering of CaO in the regeneration process.It is believed that sintering is a process of growth and physical aggregation of the crystais [5].But currently there are few researches focusing on CaO grain size in sintering and no CaO crystal growth kinetics investigation.