Abstract: The carbonation characteristics of K₂CO₃ sorbents and K₂CO₃/Al₂O₃ supported sorbents for CO₂ capture were investigated with thermogravimetric apparatus (TGA), scanning electron microscopy analysis (SEM) and N₂ adsorption. The surface areas and porosities of the sorbents were greatly improved after loading, which led to increase of reaction rate and conversion percent. It meant that carbonation characteristics of sorbents were improved. The reaction rate and conversion percent decreased with increasing diameter of pure K₂CO₃ sorbents, and slightly increased with increasing diameter of K₂CO₃/Al₂O₃ sorbents. The influence of different diameters and reaction times on the particle micro structure was studied, and the result showed a steady micro structure of the particle. A supported particle model was used to describe the carbonation process of K₂CO₃/Al₂O₃ sorbents and the model results agreed well with experimental data. The influence of different CO₂ concentrations on K₂CO₃/Al₂O₃ sorbents carbonation was computed by the model. The simulation result was reasonable and accurate, providing a foundation for further study.

Key words: CO₂ capture, K₂CO₃/Al₂O₃, adsorbents, carbonation reaction, particle model, kinetics

摘要： 利用热重分析仪、扫描电镜和氮吸附仪对不同粒径的K₂CO₃颗粒和负载型K₂CO₃/Al₂O₃二氧化碳吸收剂的碳酸化特性进行研究。负载后的吸收剂比表面积和孔隙结构得到较大改善，使得碳酸化反应速率和转化率均提高，吸收剂碳酸化特性得到改善。纯K₂CO₃颗粒吸收剂的反应速率和转化率随着粒径的增加而减小，负载型吸收剂的反应速率和转化率随着粒径的增加略增大。研究了不同粒径和反应时间对K₂CO₃/Al₂O₃颗粒微观结构的影响，结果表明K₂CO₃/Al₂O₃颗粒具有较稳定的微观结构。采用负载型粒子模型对K₂CO₃/Al₂O₃吸收剂吸收CO₂碳酸化过程进行研究，所建立的粒子模型计算结果与试验值吻合较好。利用建立的模型对不同CO₂浓度下K₂CO₃/Al₂O₃吸收剂碳酸化反应特性进行模拟计算，模拟结果具备一定的合理性和准确性，为开展进一步研究提供了基础。

关键词: CO₂捕集, K₂CO₃/Al₂O₃, 吸收剂, 碳酸化反应, 粒子模型, 动力学