流化床脱硝三氧化铀的氨裂解气还原研究

THE CRACKING AMMONIA REDUCTION KINETICS OF DENITRATED URANIUM TRIOXIDE

应用等温热重法研究了由流化床脱硝三氧化铀的氨裂解气还原动力学,结果表明,在温度为550～660℃和转化率为0～95％的范围内,反应动力学服从Sepencer-Toply方程,符合未反应核化学反应控制模型,测得还原反应的表观活化能为133.8kJ/mol。实验证明氨裂解气还原过程与氢氮混合物(3H_2+N_2)的基本相同。测定了氢分压和水蒸气分压对还原反应的影响,求得氢的分压指数为0.57。水蒸汽的存在,明显的抑制了还原反应速度。

The cracking ammonia reduction kinetics of UO_3 denitrated in fluidized bed has been studied with thermograyimetric method. The results show that the reduction kinetics of UO_3 obeys Spencer-Toply equation within 0—95% conversion in range of 550-660℃ which coincides with chemical reaction controlled unreacted-core model. The apparent activation energy of reduction reaction is found to be 133.8 kJ/mol. There is comparison between effects of cracking ammonia and mixture of hydrogen and nitrogen (3H_2+N_2) on reduction rate of UO_3. The effects of partial pressure of hydrogen and water vapour on reduction rate are examined. The hydrogen partial pressure exponent is found to be 0. 57. The water vapour restricts obviously reduction rate of UO_3.