The hydrogen process of calcium-based absorbents is currently one of the important ways to promote the efficient and clean utilization of coal. One potential issue with carbonation-calcination is that the reaction activity and stability are frequently challenged by a few factors such as changes in pore structure and surface area. To address this issue, in this paper, 15 cycles of carbonation-calcination were carried out in a tube furnace, and the carbonation-calcination products were prepared separately for each cycle. The microstructure of the products was characterized, and the key parameters of stable reaction activity were studied. First, the CaO particle size distribution model was developed according to the volume mean particle size (X-ray diffraction) and the actual particle size (Transmission electron microscopy). Then, the effect of CaO particle size distribution on the carbonation reaction's fast stage and the ultimate CaO conversion were discussed. The model of particle size distribution is used to improve the stability of reaction activity in the circulation process and optimize the preparation process of calcium-based sorbents for calcium looping applications.

CaO,reaction activity,Particle Size,calcium looping