内配碳团块CO-CO_2气氛下反应行为的研究

Study on reaction behavior of ore-carbon briquette in CO-CO_2 atmosphere

为了建立内配碳团块CO-CO_2气氛下反应的数学模型并验证模型的正确性,根据还原动力学原理模拟计算内配碳团块在CO-CO_2气氛下的还原过程,通过对不同温度下的团块还原度、团块碳转化率的模拟值和实验值之间的比较证明了模型的可靠性。经过研究发现模型的反应包括了铁氧化物的逐级还原、碳的Boudouard反应和金属铁的再氧化。在1 473 K和CO-CO_2气氛下对内配碳团块的反应进程的模拟分析表明,在早期阶段内配碳团块显示出自还原的特征;在团块达到其最大还原度时,团块内氧化铁还原和金属铁再氧化同时存在;在后期阶段,团块内主要是金属铁的再氧化反应。在1 473 K和CO-CO_2气氛下对影响内配碳团块反应行为的相关因素的模拟结果表明,改变铁矿粉反应性或还原剂气化性不能有效提高内配碳团块的最终还原度,但是减小孔隙率可以提高团块的最终还原度。

In order to establish a mathematical model for the reaction of carbon-doped aggregates in CO-CO2 atmosphere and verify the model,the reduction process of carbon-doped aggregates in CO-CO2 atmosphere was simulated and calculated based on the principle of reduction kinetics.The reliability of the model was verified by comparing the simulated and experimental values of the reduction degree and the carbon conversion rate of carbon-doped aggregates at different temperatures.It was found that the model reactions included the step-by-step reduction of iron oxides,Boudouard reaction of carbon,and reoxidation of metallic iron.An analysis on the briquette reaction progress at 1 473 K and in CO-CO2 atmosphere showed that the briquette presents the characteristics of self-reduction in the early stage.When the briquette reaches its maximum reduction degree,both iron oxide reduction and metallic iron reoxidation occurred.In the later stage,the main reaction in the briquette was metallic iron reoxidation.The simulation results of the factors influencing the briquette reaction behavior at 1 473 K and in CO-CO2 atmosphere showed that altering the reactivity of iron ore fines or altering the gasification of the reductant could not improve the final reduction degree,while decreasing the porosity could significantly improve the reduction degree of the metallic product.