300 t复吹转炉底吹系统优化模拟

 顶底复合吹炼转炉炼钢法是当下主流的炼钢方法,底部供气元件的种类、支数、排布方式和底吹供气强度直接影响着转炉熔池的混匀效果,合理的流场不仅可以降低生产成本,更能缩短冶炼周期,增加企业效益。基于冷态水模拟以及CFD数值模拟手段各自的研究特点,以某钢厂300 t转炉为原型,将不同底吹条件下熔池的混匀时间、死区以及弱流区体积作为评判依据,对300 t转炉的底枪排布方式、底吹供气模式(非均匀供气和均匀供气)以及底吹供气强度进行了系统研究,研究结果表明,当底枪排布位置由0.3D(D为炉底直径)到0.5D,底吹系统对炉壁处钢液的搅拌能力明显增强,但熔池内死区以及弱流区体积却会明显增加,使得整个熔池混匀时间增长;在对适宜底吹强度研究发现,当熔池底吹强度的临界值为0.28 m3/(t·min),此底吹强度下对熔池的搅拌效果最好;底吹系统对熔池的搅拌效果会随着供气模式的不同而改变,当底吹流量分配为2:1时,底吹系统对熔池的搅拌效果最佳,均匀供气模式(1:1)次之,而当分配比为3:1和4:1时,由于熔池的大流量侧供气强度相对较大,会极大影响底吹系统对熔池的搅拌效果。

Optimization and simulation of bottom blowing system for 300 t combined blown converter

The top and bottom composite blowing converter steelmaking method is the mainstream steelmaking method at present. The type, number, arrangement mode and bottom blowing gas supply intensity of the bottom gas supply element directly affect the mixing effect of the converter molten pool. The reasonable flow field can not only reduce the production cost, but also shorten the smelting cycle and increase the enterprise benefit. Based on the research characteristics of cold water simulation and CFD numerical simulation, a 300 t converter in a steel plant was taken as the prototype, and the mixing time, dead zone and weak flow zone volume of the molten pool under different bottom blowing conditions were evaluated. The bottom lance arrangement, bottom blowing gas supply mode (non-uniform gas supply and uniform gas supply), and bottom blowing gas supply intensity of 300 t converter are systematically studied. The results show that when the position of the bottom lance is from 0.3D (D is the diameter of furnace bottom) to 0.5D, the stirring capacity of the bottom blowing system on molten steel at the furnace wall is obviously enhanced, but the volume of the dead zone and weak flow zone in the molten pool increases obviously, which makes the mixing time of the whole bath increase. It is found that when the critical value of bottom blowing strength is 0.28 m3 / (t·min), the stirring effect is the best. The stirring effect of the bottom blowing system on the molten pool will change with the different gas supply modes. When the bottom blowing flow distribution is 2:1, the bottom blowing system has the best stirring effect, followed by the uniform gas supply mode (1:1). When the distribution ratio is 3:1 and 4:1, the stirring effect of the bottom blowing system on the molten pool will be greatly affected due to the relatively large gas supply intensity on the large flow side of the bath.