CuCl2改性飞灰吸附气相零价汞

Adsorption of gaseous elemental mercury on CuCl2-modified fly ashe

采用CuCl2对循环流化床锅炉飞灰进行改性,在固定床反应器上对CuCl2改性飞灰进行了气相零价汞(Hg0)吸附实验。考察了CuCl2负载量和吸附温度对改性飞灰Hg0吸附能力的影响,并结合颗粒内扩散模型、准一阶动力学模型、准二阶动力学模型和耶洛维奇模型拟合结果分析该过程的控制步骤。结果表明:CuCl2改性飞灰的Hg0穿透时间远大于未改性飞灰,对Hg0的吸附量随CuCl2负载量的增加而增加;CuCl2改性飞灰的Hg0吸附能力随吸附温度的升高先增大后减小,150℃为最佳吸附温度;准二阶动力学模型的拟合值与实验值相关系数最高,且该模型初始吸附速率与实验值最为接近,即准二阶动力学模型更适合于描述CuCl2改性飞灰的Hg0吸附过程。

The fly ash in circulating fluidized bed boiler was modified with CuCl2,and the experiment for adsorption of gaseous elemental mercury(Hg^0)on it was carried out in a fixed bed reactor.The effects of CuCl2 loading and adsorption temperature on adsorption capability of modified fly ash to Hg^0 were investigated,the control steps of this process are analyzed by the fitting results of intra-particle diffusion model,quasi-first-order kinetic model,quasi-second-order kinetic model and Elovich kinetic model.The results show that:The Hg0 penetration time of CuCl2-modified fly ash is much longer than that of non-modified fly ash,while the Hg^0 adsorption quantity increases with the increase of CuCl2 loading;The Hg^0 adsorption quantity of the modified fly ash increases first and then decreases with the increase of adsorption temperature and is the highest at 150℃;The correlation coefficient between the quasi-second order kinetic model fitting results and the experiment results is the highest,and the initial adsorption rate of this kinetic model is the closest to the experimental value,which indicates that the quasi-second order kinetic model is more applicable to reflect Hg^0 adsorption on CuCl2-modified fly ash.