钙基CO_2吸收剂循环活性衰减原因初探

对钙基CO2吸收剂的循环活性衰减进行了实验研究,考察了随着循环次数的增加,吸收剂的表面形态、吸收剂分子孔径及比表面积等微观结构的变化,分析了钙基CO2吸收剂循环活性衰减的原因。结果表明,随着循环次数的增加,吸收剂晶粒中的片状结构已经完全消失,取而代之的是正方体状的大晶粒,晶粒生长严重,大量空隙被封闭。而由此引起的吸收剂的比表面积的不断减小和孔容积的降低以及孔分布的改变,导致了吸收剂循环活性的衰减,吸收剂的循环转化率降低。

Activity decline of Ca-based CO_2 absorbent in repetitive calcination-carbonation

The carbonation characteristics and the decline of reactivity for recycle Ca-based CO₂ absorbent were investigated. The microstructure, pore radius and specific surface area of the absorbent changed with the number of cycles, leading to the decline of the absorbent reactivity. The results show that, the lamellar structure in the absorbent disappears, which changes to bigger cubic crystals, and most apertures were blocked. It reduces the specific surface area and total cumulative volume and changes the distribution of pore radius, and then the reactivity of Ca-based CO₂ absorbent and the absorption capability decline as the number of cycles increases.