RH精炼过程吹气对喷粉脱硫影响的数值模拟

Numerical simulation of gas blowing effect on powder injection desulfurization during RH refining process

为研究RH精炼过程吹气参数对喷粉脱硫的影响规律,进而提高喷粉脱硫的效率,以实际230 t RH喷粉脱硫过程为研究对象,建立三维耦合的k-ε湍流模型、流体体积(VOF)模型、离散相模型(DPM)、用户自定义标量(User Defined Scaler, UDS)以及未反应核脱硫动力学模型,讨论了浸渍管吹气流量、真空室侧吹以及钢包底吹对钢液流速以及喷粉脱硫的影响。结果表明,脱硫剂在喷入真空室后主要集中在靠近下降管一侧的真空室相交界面上,并随着钢液循环流动从下降管进入钢包,钢包中脱硫剂也趋向于在下降管一侧聚集。钢液流速以及脱硫速率随着浸渍管吹气流量的增大而增大,但吹气流量(标准状况)从1 000 L/min增大至2 000 L/min时,钢液流速以及脱硫速率增大幅度较小;继续将吹气流量从2 000 L/min增大至3 000 L/min时,钢液流速增大明显,但终点脱硫效率只增加了4.0%。真空室侧吹流量为2 000 L/min时,钢液流速和脱硫速率略微增大。在上升管对应的钢包底部进行200 L/min的底吹时,钢包内钢液流速明显增大,但脱硫速率则由于钢包内脱硫剂停留时间的减小而发生了降低。本研究为提高RH精炼过程喷粉脱硫效率提供了理论基础。

In order to study the influence of gas injection parameters on the powder injection desulfurization during RH refining process and improve the efficiency of desulfurization,three-dimensional coupled k-εturbulence model,volume of fluid(VOF)model,discrete phase model(DPM),user defined scaler(UDS),and unreacted core desulfurization kinetic model were established based on the powder injection desulfurization process of an actual 230 t RH.The effects of the circulation flow rate of snorkel,injection at the vacuum chamber side,and injection at the ladle bottom on the speed and powder injection desulfurization of molten steel were discussed.The results show that the desulfurizers are mainly concentrated on the interface of vacuum chamber near the downleg side after it is sprayed into the vacuum chamber,and desulfurizers enter the ladle from the downleg with the circulating flow of molten steel.The desulfurizers in the ladle also tend to accumulate on the downleg side.The speed and desulfurization rate of molten steel increase with the increase of the circulation flow rate of snorkel,but the increase is small when the circulation flow rate(standard condition)increases from 1000 L/min to 2000 L/min.When the circulation flow rate continues to increase from 2000 L/min to 3000 L/min,the speed of molten steel increases significantly,but the end-point desulfurization efficiency only increases by 4.0%.The speed and desulfurization rate of molten steel increase slightly with the 2000 L/min side injection at the vacuum chamber.When the gas injection with 200 L/min flow rate is carried out at the bottom of the ladle corresponding to the up snorkel,the speed of molten steel in the ladle increases significantly,but the desulfurization rate decreases due to the decrease of residence time for desulfurizer in the ladle.The study provides a theoretical basis for improving the efficiency of the powder injection desulfurization during RH refining process.