焙烧HDS失活催化剂提取钒的动力学

Kinetics of roasting HDS spent catalyst for recovery vanadium

在固定床反应器中 ,用空气焙烧HDS失活催化剂 ,再用碳酸钠水溶液浸取钒和钼。研究了钒焙烧转化率随失活催化剂粒径、焙烧温度及焙烧时间的变化关系 ,结果表明 :实验数据可以用收缩未反应核模型拟合。当催化剂平均粒径小于 6 0 μm ,或在较低反应温度及较低转化率下 ,内扩散阻力可以忽略不计 ,过程受化学反应控制 ;而当平均粒径大于 6 0 μm ,且在较高反应温度及较高转化率下 ,过程同时受化学动力学与内扩散控制。分别导出了 2种情况下焙烧钒的动力学方程式 ,并按方程式计算得到反应温度在 92 3～ 112 3K时的活化能为 5 6 .12kJ·mol-1。

Vanadium can be recovered from spent HDS catalyst by roasting it with air in a fixed bed reactor and then immersing roast product with sodium carbonate solution. The relationship between vanadium recovery and catalyst diameter, roasting temperature and roasting time is investigated. The experiment results indicate that the roasting reaction kinetics can be expressed by the shrinking core model. When catalyst particle diameter is <60 μm, the roasting process is judged as reaction controlled step . At the conditions of diameter >60 μm,high roasting temperature and large vanadium recovery, the process rate is controlled by reaction and inner-diffusion simultaneously. The kinetics equations for two different controlled steps are found . The activation energy within 923～1 123 K is 56.12 kJ·mol -1