煅烧温度对石灰石循环分离CO_2的影响及动力学分析

Process and Kinetic Analysis of Cyclic CO_2 Capture Using Limestone under Different Calcination Temperatures

在热重分析仪上研究了煅烧温度对石灰石循环分离CO2特性的影响,并利用两段的收缩核模型考察了不同煅烧温度下循环碳酸化反应过程动力学参数的变化规律。结果表明:煅烧温度和循环次数的增加皆导致化学反应控制阶段提前结束,致使产物层扩散控制阶段提前,导致CaO最终转化率随煅烧温度和循环次数的增加而降低。较高的煅烧温度致使化学反应控制阶段表观反应速率常数较小且随着循环次数的增加而快速降低,产物层扩散控制阶段表观速率常数较大且随着循环次数的增加而缓慢降低。

The effect of calcination temperature on cyclic CO2 capture characteristics using limestone was experimentally investigated in a thermogravimetrie analyzer. In addition, kinetic parameters of the multiple carbonation cycle reactions at different calcination temperature were investigated using the two stages of shrink core model. The resuhs show that the finish-time of the chemical reaction controlling stage is shortened and it results in a decrease of eventual CaO conversion rate with the increase of calcination temperature and cycle numbers. Higher calcination temperature leads to a trend that the chemical reaction controlling stage is lower and decreases quickly with the in- crease of cycle numbers. While, it still results in another trend that apparent chemical reaction rate constant of the product layer diffusion controlling stage is larger and decreases slowly with the increase of cycle numbers.