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为了分析真空热还原制取金属锂的还原效率和还原率,综合考虑罐内球团传热和化学反应,建立了传热与反应动力学耦合模型.利用该模型对单球团和还原罐内球团还原过程进行数值模拟,得到了球团温度及还原率的时间分布,并分析了罐外换热系数对球团还原过程的影响.结果表明:球团低导热率和反应等效热汇是影响还原过程的主要因素,罐中心区域和罐壁处的温度和反应速率存在较大差值;还原初期传热为还原过程的主要控制因素,而反应后期化学反应为主要控制因素;罐外换热系数对还原过程影响不大,增强罐内传热是提高还原效率的有效途径.
In order to analyze the reduction efficiency and reduction rate of metal lithium prepared by vacuum thermal reduction, a coupled model of heat transfer and reaction kinetics was established by comprehensively considering the heat transfer and chemical reaction in the canned pellets. The process of pellet reduction was numerically simulated to obtain the time distribution of pellet temperature and reduction rate, and the influence of the heat exchange coefficient outside the tank on pellet reduction was analyzed.The results show that the low thermal conductivity of pellets and the equivalent heat exchange Is the main factor affecting the reduction process. There is a big difference between the temperature and the reaction rate at the tank center and the tank wall. The heat transfer during the initial reduction is the main control factor for the reduction process, while the chemical reaction is the main control factor during the late reaction period. The heat transfer coefficient has little effect on the reduction process, and enhancing the heat transfer inside the tank is an effective way to improve the reduction efficiency.