精砂粉悬浮冶炼反应塔闪速炼铁工况优化研究

Optimization of flash ironmaking in suspension smelting furnace for iron concentrate powder

为了对粉状铁精砂悬浮冶炼反应塔工况进行优化研究,采用数值仿真模拟技术对反应塔内多物理场进行分析,并通过正交实验对基本工况进行优化。在基本工况下,在0~6 m高度范围内工业氧形成向下运动并且逐渐扩张的气柱,6 m后气柱直径趋于稳定,且在0~5 m高度区域有对称分布的回流漩涡;高温区域出现在2.5~5.5 m高度区域,最高温度为2 590 K;铁矿颗粒进入反应塔后温度逐渐上升,在高温作用下Fe2O3依次还原为Fe3O4和Fe O最终生成Fe,在7.5 m处固体颗粒中Fe质量分数达到95%,铁精砂基本反应完成。通过正交试验分析,得到优化方案为A3B3C1,即中央氧和侧氧速度配比为3.5,工业氧质量分数为95%,煤粉投放量为3.06 t/h。在优化方案下,反应塔内高温区温度降低且低温区缩小,铁精砂冶炼基本完成,所需高度从7.5 m降低至5.0 m,反应塔出口气体中CO平均质量分数从17.8%降低至12.1%。

In order to optimize the working conditions of the reaction tower for suspension smelting of powdered iron concentrate,numerical simulation was used to analyse the multi physical fields and orthogonal test was used to find the most suitable parameters.Under the basic working condition,the industrial oxygen forms a downward movement and gradually expands within 0-6 m and the diameter of the stream column tends to be stable after 6 m.There are symmetrically distributed reflux vortices in the area of 0-5 m.For the gas phase,the high temperature area occurs in the area of 2.5-5.5 m,with the maximum temperature of 2 590 K.However,the temperature of iron concentrate powder gradually increases after entering the furnace.In the reduction reaction,Fe2O3is successively reduced to Fe3O4and Fe O,and Fe is finally generated.Fe mass fraction in solid particle reaches 95%at 7.5 m,indicating that the iron-making process is completed.According to the orthogonal test,the optimized condition is A3B3C1,i.e.,the velocity ratio of central oxygen and side oxygen is 3.5,the concentration of industrial oxygen is95%,and the dosage of pulverized coal is 3.06 t/h.Under the optimized condition,the highest temperature is decreased and the low-temperature zone is reduced.The height required for the basic completion of ironmaking process is reduced from 7.5 m to 5.0 m.The average mass fraction of CO in the outlet gas is reduced from 17.8%to 12.1%.