氧化锌脱硫中氧的气氛效应及动力学表征

THE ATMOSPHERE EFFECT OF OXYGEN & KINETICS FOR H_2S REMOVAL BY ZnO DESULFURIZER

用热重法研究了含氧气氛中Ｔ３０５氧化锌脱硫剂脱除Ｈ_２Ｓ的微观动力学。实验表明，２００～２９０℃温度范围，脱硫初期为化学反应控制，中后期转移为晶粒扩散控制。Ｏ_２存在会阻碍反应进行。气氛中Ｏ_２含量小于０．４％（ｍｏｌ）时，在不同控制区，过程对Ｏ_２均为－０．５级；Ｏ_２含量超过０．４伴随着深度氧化而使脱硫过程复杂化。脱硫反应动力学行为可用未反应收缩核模型描述。给出了不同控制区的参数估值及动力学表达式。对反应后粉末及球形颗粒进行了ＥＰＭＡ分析。

The microkinetics of H_2S removal by zinc oxide (T305) was sutdied in the presence of O_2 by using thermogravimetric methods,The experiments under 200-290℃ showed that the overall process was controlled by the surface reaction in the initial-stage,but by grain diffusion at the mid-and last-stages,The reaction order is-0.5 for O_2,at below 0.4(mol%).Because of possible deep oxidation the reaction become complicated with increase of oxygen concentration, The kinetic behavior of the reaction could be described by the shrinking core model. The model parameters were estimated. The EPMA results for reacted powder and spherical particle of ZnO desulfurizer were analyzed.