活性炭脱除SO2吸附动力学模型及数值模拟

由于内扩散阻力的影响，对于粒径在3 mm及以上的活性炭颗粒脱除SO2，采用以气膜控速为基础的LDF模型存在很大的误差。建立了适合3 mm以上活性炭颗粒脱除SO2的气固床传质模型，考察了活性炭吸附不同SO2浓度时几种吸附动力学模型的相关性系数，讨论了影响活性炭颗粒吸附SO2的控制步骤；以固相扩散模型为基础，研究了单颗粒下不同吸附动力学模型为基础的吸附速率方程吸附速率与吸附量之间的关系；以Vermeulen模型作为粒内推动力模型，建立了穿透曲线模型并与实验值进行了比较。研究表明，活性炭吸附SO2主要为内扩散控制，可以使用Boyd模型进行描述；以Boyd模型为基础的Vermeulen模型能够很好地预测活性炭颗粒吸附速率与吸附量之间的关系；以Vermeulen模型为推动力建立的穿透曲线模型可以精确地预测3 mm及以上活性炭颗粒在不同SO2浓度和不同空塔线速度下的出口浓度。

Kinetic models and numerical simulation of SO2 adsorption on activated carbon

Due to the impact of diffusion resistance，the linear driving force model (LDF) which is controlled by internal diffusion is not suitable to predict the adsorption of SO2 on activated carbon with size over 3 mm.Therefore，it will be of significance to develop a better mathematical model.In this paper，the authors investigated the correlation coefficients between several adsorption kinetic models with different concentrations of SO2.In addition，the authors discussed the controlling steps of the adsorption.According to the solid diffusion model，the authors researched the relationship between the velocity of adsorption and the amount of adsorption based on the different force model of a single particle.Finally，the authors built a breakthrough curve model with the Vermeulen model as the particle driving force model，and compared the experiment data.The results show that the internal diffusion is the controlling step of the adsorption of SO2 with the size over 3 mm，and it can be described by the Boyd model.The breakthrough curve model，using the Vermeulen model as the particle driving force model，can accurately predict the experiment with different SO2 concentrations when the particle size is over 3 mm.The result provides an important evidence for the simulation of SO2 adsorption inside the gas-solid bed which is filled with the activated carbon of the size over 3 mm.