CuO/Al2O3脱硫反应单颗粒模型化研究

Modeling of flue gas SO_2 removal with CuO/Al_2O_3

针对氨再生CuO/Al2O3脱硫反应只发生在固体内外表面的CuO上这一特性,在粒子模型基础上,建立了描述氨再生CuO/Al2O3脱硫的单颗粒数学模型,并在热重分析仪上进行了CuO/Al2O3颗粒脱硫反应动力学的研究,将反应过程中CuO逐步变为CuSO4、孔隙率逐渐减小及气相SO2的有效扩散系数逐渐降低的现象用经验式De=α(1-x)b表达,从而使结构变化对反应的影响在颗粒模型中体现出来。模型预测与实验结果吻合良好。数值分析表明,孔扩散对CuO/Al2O3颗粒脱硫反应进程起重要作用,扩散活化能随反应的进行而增大。

Considering the reaction of SO2 and surface CuO, a mathematical model based on the grain model was developed to simulate the SO2 removal process over a NH3-regenerated CuO/Al2O3 pellet. SO： removal from flue gas over CuO/Al2O3 pallets of various sizes was carried out in a thermo-gravimetric analyzer to study the effects of reaction temperature, particle diameter and porosity, and to validate the single particle model developed. The reaction of CuO with SO2 and O2 yields CuSO4 that is larger in molecular size than CuO and results in a decrease in particle porosity and gas diffusivity. The effective SO2 diffusivity can be correlated with CuO conversion by De = α （1 -x）^b, which allows the model to fit the experimental data better. Mathematical analysis using this particle model indicates that the pore diffusion is important for the SO2 removal over CuO/Al2O3 pallets and the activation energy of pore diffusivity increases with the reaction going on.