基于气液固三相流模拟的电炉侧吹优化
Side-blowing optimization of electric arc furnace based on gas-liquid-solid three-phase flow simulation
-
摘要: 康斯迪(Consteel)电弧炉是目前国内广泛使用的电炉炼钢设备, 其熔池搅拌工艺对冶炼具有重要的影响。绝大多数电炉配备了侧吹技术, 少数电炉匹配了底吹技术。侧吹氧枪(或烧嘴)除了切割废钢、消除冷点等作用以外, 对改善熔池均匀性具有关键作用。为提高钢液流动及混匀效率, 本文基于气液固三相流模拟了电炉侧吹工艺对熔池流场的影响。以某厂150 t康斯迪电弧炉及其侧吹氧枪为原型, 制作了相似比1∶8的水力学模型。基于流体力学相关理论, 提出了非均匀流量的侧吹布置方式。对不同侧吹条件下气液固三相流的运动行为及废钢模拟物的熔化现象进行了模拟试验。以平均混匀时间、流场运动情况及废钢模拟物熔化情况作为判据, 得到了优选的非均匀气量布置方案。结果表明, 模拟侧吹氧枪水平方向偏转10°是本试验的优选角度。在水平偏转10°的条件下, 侧吹气量越大越有利于混匀。但当气量较大时, 增大相同气量引起的平均混匀时间降低程度显著减小, 气体能量利用率降低。在一定的侧吹强度下, 当增大侧吹总气量时, 相对于均匀增加每支枪的气量, 集中增加某支侧吹的气量更有利于混匀。在本试验的S4条件下, 4号侧吹枪处于加料区和偏心炉底出钢区域(EBT区)2个冷区的交界, 相同气量下, 平均混匀时间最短, 气体利用率增大了15%。此时, 液相混匀和废钢运动速度更快。同时进入冷区的废钢数量有所减少, 堆积和黏结情况明显减轻。综合来看, 是优选的非均匀布置方式。本试验研究结果为电炉实际侧吹氧枪的位置调整和工艺参数优化提供了借鉴和指导作用。Abstract: Consteel electric arc furnace (EAF) is a high-efficiency, green and low-carbon steelmaking equipment widely used in China, and its molten pool stirring process has an important influence on smelting. Most of them are equipped with side-blowing technology, while a few feature bottom-blowing systems. The side-blowing oxygen lances (or burners) play a key role in improving the uniformity of the molten pool in addition to cutting scrap steel and eliminating cold spots. To enhance the flow and mixing efficiency of molten steel, this paper simulates the impact of the side-blowing process on the flow field within the molten pool based on gas-liquid-solid three-phase flow. A hydraulic model with a similarity ratio of 1∶8 was made based on a 150 t Consteel EAF and its side-blowing oxygen lances. Referring to fluid mechanics theory, a side-blowing arrangement with non-uniform gas flow was proposed. Simulated tests were then conducted to study the movement behavior of gas-liquid-solid three-phase flow and the melting phenomenon of scrap simulants under different side-blowing conditions. The average mixing time, flow field movement and melting of scrap simulants were used as criteria to obtain the preferred non-uniform gas volume arrangement scheme. The results show that a 10° horizontal deflection of the simulated side-blowing oxygen lances is the optimal angle in this study. At a horizontal deflection of 10°, increasing the side-blowing gas volume is more conducive to mixing. However, when the gas volume is large, the reduction in average mixing time caused by increasing the same gas volume is significantly reduced, and the gas energy utilization rate decreases. Under a certain side-blowing intensity, when increasing the total side-blowing gas volume, concentrating the gas volume increase on one specific side-blowing lance is more conducive to mixing than uniformly increasing the gas volume of each lance. Under the S4 condition of this study, the No.4 side-blowing lance is located at the junction of two cold zones, the feeding zone and the eccentric bottom tapping(EBT) zone. Under the same gas volume, this configuration achieves the shortest average mixing time and increases the gas utilization rate by 15%. At this time, the liquid phase mixing and scrap simulant movement speed are faster. Meanwhile, the amount of scrap entering the cold zones decreases, and the accumulation and bonding phenomena are significantly alleviated. Overall, this is the preferred non-uniform arrangement. The results of this experimental study provide reference and guidance for the position adjustment and process parameter optimization of actual side-blowing oxygen lances in EAFs.
下载: