关键词: 二氧化碳捕集, 钙循环, 氯, 动力学, 烧结

Abstract: The CO₂ capture peformance of the CaCO₃ doped with Cl through impregnation method was investigated in a dual fixed-bed reactor together TGA measurment. A gas-solid ion reactive adsorption kinetics model was employed to describe the chemical-reaction controlled stage of the carbonation process of the sorbent. The results show that the existence of Cl has negative effect on the CO₂ capture with the calcium based sorbent. When the Cl/Ca molar ratio is greater than 0.25%, both the carbonation rate and the lasting time during the chemical reaction controlled stage decrease with the increae of the Cl/Ca molar ratio, leading to a low ultimate carbonation conversion in this stage. The pore distribution of the Cl^- doped sorbent were analyzed through N₂ adsorption method. The existence of Cl leads to a lower BET surface area and reduced pore distribution in the range of 10-120nm, resulting in higher CO₂ diffusion resistance in the sorbent and less CaO that can react with CO₂. Thus, the carbonation rate and ultimate conversion of the Cl^- doped sorbent in the chemical reaction controlled stage are lower. Therefore, high content Cl in the final sorbents should be avoided when choosing calcium materials as CO₂ sorbent or synthesizing high reactive calcium-based sorbent.

Key words: CO₂ capture, calcium looping process, chlorine, kinetics, sintering