石灰石直接硫化反应动力学研究  

Direct Sulfation Reaction Kinetics of Limestone

作　　者：陈传敏[1] 赵长遂[2] 赵毅[1] 

机构地区：[1]华北电力大学环境科学与工程学院,保定071003 [2]东南大学洁净煤发电及燃烧技术教育部重点实验室,南京210096

出　　处：《燃烧科学与技术》2009年第5期388-392,共5页Journal of Combustion Science and Technology

基　　金：国家重点基础研究发展计划(973)资助项目(2006CB705806-01);华北电力大学博士学位教师科研基金资助项目

摘　　要：采用热重分析法研究了石灰石直接硫化反应过程,结果表明,直接硫化可以使Ca达到很高的转化率,而且直接硫化速率随Ca转化率的升高而减小,随温度的升高而增大.用收缩未反应核模型对其反应过程进行了表征,得到石灰石直接硫化反应的速率常数Ks及产物层扩散系数De的Arrhenius表达式.石灰石直接硫化反应动力学分析表明,石灰石直接硫化在开始时由化学反应动力学控制,一旦CaSO4产物层形成,逐渐变为由通过产物层扩散控制.表观活化能和有效扩散系数分析表明通过产物层扩散为固态离子扩散.The direct sulfation reaction processes of limestone were investigated by the thermogravimetric analysis method. Compared with sulfation of precalcined limestone （CaO） , direct sulfation of limestone can achieve higher Ca conversion. Direct sulfation reaction rate rises with temperature and decreases with sulfation degree. The kinetic behavior was expressed by the shrinking unreacted core model. The Arrhenius expressions of direct sulfation rate constant, effective diffusivity of CaSO4 product layer, were calculated and explained according to the model. The kinetic analyses show that direct sulfation reaction is chemically controlled before CaSO4 product layer forms and controlled by diffusion through product layer after CaSO4 product layer forms. The high value of activation energy and low value of effective diffusivity of CaSO4 product layer under diffusional control suggest that mass transport through product layer occurs by means of a solid-state ionic mechanism.

关 键 词：直接硫化 收缩未反应核模型 石灰石 动力学 

分 类 号：X511[环境科学与工程—环境工程]