The gas-solid reaction and breakthrough curve of CO2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO2 capture at 550 degrees C. Calcium oxide sorbent after reaction can be easily regenerated at 900 degrees C by pure N-2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO2 were controlled by a combination of the surface chemical reaction and diffusion of product layer. (c) 2010 Elsevier B.V. All rights reserved.