复合钙硅固硫剂的固硫反应动力学研究

Desulfurization and Kinetic Studies on CaCO_3-SiO_2 Complex Desulfurization Reagent

用机械混合法、沉淀法及溶胶 -凝胶法制备了 Ca-Si系列复合固硫剂 ,并用热分析法分别研究其固硫性能和固硫过程 ,用等效粒子模型对固硫反应的动力学过程进行表征 ,计算了各固硫反应的动力学参数 .研究结果表明 ,氧化钙固硫动力学参数活化能与指前因子之间存在着耦合现象 ,即反应活化能 Ea 下降时 ,指前因子 k0 相应下降 ,反之 ,活化能增加时 ,指前因子相应增加 .用不同方法制备的 Ca-Si复合固硫剂的固硫性能和固硫过程有明显差别 ,但其固硫率都高于纯 Ca CO3 ,其中溶胶 -凝胶法效果最好 ;Ca-Si系列复合固硫剂对固硫反应的影响表现为在反应初期 (即化学反应控制阶段 ) ,其反应速率较纯 Ca CO3 的低 ;而到反应后期 (即产物层扩散控制阶段 ) ,其反应速率显著增加 ,固硫反应温度越高 ,这种影响越明显 ,与固硫转化率的实验结果非常吻合 .

In this paper, Ca-Si complex desulfurization reagent was prepared by precipitation, sol-gel and mixing method. Then the effect on desulfurization among differet samples was studied. The grain model of the reaction kinetic was used. It is shown that this model can describe the course of desulfurization. Different samples have different effects on the kinetic parameter such as E a and k 0, which couple to each other(the accretion of E a always accompanies the accretion of k 0 and vice versa). The sol-gel-Ca-Si reagent gives the best performance on desulfurization. At the beginning of the reaction, the complex Ca-Si reagent shows the slow rate, but in the end, it is obviously faster, further more, the higher the temperature of the reactions, the greater the effect.