复吹转炉渣金间传质物理模拟及应用

Physical modeling of mass transfer between slag and metal in combined blown converter and application

将200t复吹转炉按照1∶12的比例缩小,用液体石蜡模拟炉渣、水模拟钢水、压缩空气模拟顶吹和底吹气体,在实验室建立模拟复吹转炉吹炼过程熔池渣金间传质的试验模型,在顶吹气体流量为88m^(3)/h条件下,通过相对集中非对称布置的4、6、8、10、12支底枪吹入不同底吹气体,用苯甲酸作为传输物质,试验测定了复吹转炉熔池渣金间的容量传质系数,考察不同底枪支数和布置以及底吹气体流量对渣金间传质速率的影响,优化复吹转炉底枪布置和底吹气体流量,以增强复吹转炉熔池的搅拌,改善熔池渣金反应动力学条件。研究结果表明,当底吹气体流量为1.14m^(3)/h时,在4~12支的底枪布置方案中,4、6支底枪布置方案的容量传质系数(分别为1.77×10^(-4)、1.80×10^(-4)L/s)低于8、10、12支底枪布置方案的容量传质系数(分别为2.41×10^(-4)、2.24×10^(-4)、2.42×10^(-4)L/s);当底吹气体流量为0.57m^(3)/h时,在8~12支底枪布置方案中,10、12支底枪布置方案的容量传质系数(分别为1.68×10^(-4)、1.69×10^(-4)L/s)明显大于8支底枪布置方案的容量传质系数(0.95×10^(-4)L/s);在底吹气体流量不小于1.14m^(3)/h后,8、10、12支底枪布置的容量传质系数相差不大,在2.24×10^(-4)~2.87×10^(-4)L/s的范围;在气体流量小于1.14m^(3)/h时,随着底吹气体流量的增加,渣金间的容量传质系数增加显著,底吹气体流量大于1.14 m^(3)/h后,容量传质系数增加变缓。将12支底枪布置方案应用到实际复吹转炉,整个炉役的平均碳氧积为0.00196×10^(-4),在不同炉龄阶段,终点钢水平均碳氧积为0.00188×10^(-4)~0.00204×10^(-4),终点钢水碳氧积小于0.0025×10^(-4)的炉次比例达到90.53%。

Mass transfer between slag and metal in a 200tcombined blown converter was simulated in a model with 1∶12geometrical scale.Liquid paraffin was used to simulate slag,water to simulate molten steel,and compressed air to simulate top and bottom gases.Influence of relatively concentrated and asymmetric configurations of 4,6,8,10and 12bottom tuyeres and bottom gas flowrates on the mass transfer rate between slag and metal in the converter was investigated with benzoic acid as transport material under the condition of 88m^(3)/h top gas flowrate in order to optimize configuration of bottom tuyeres,enhance stirring in the combined blown converter bath and improve dynamic conditions of slag and metal reactions.It is known from the investigation that the volumetric mass transfer coefficients(1.77×10^(-4)and 1.80×10^(-4)L/s,respectively)from cases of 4and 6bottom tuyeres at 1.14m^(3)/h bottom gas flowrate is lower than those(2.41×10^(-4),2.24×10^(-4)and 2.42×10^(-4)L/s,respectively)of the cases of 8,10and 12bottom tuyeres for the configurations of 4-12bottom tuyeres used in this research.At the bottom gas flowrate of 0.57m^(3)/h,the volumetric mass transfer coefficients(1.68×10^(-4)and 1.69×10^(-4)L/s,respectively)from the cases of 10and 12bottom tuyeres are higher than that(0.95×10^(-4)L/s)from the case of 8bottom tuyeres.At bottom gas flowrates higher than 1.14m^(3)/h,the volumetric mass transfer coefficients from the cases of 8,10and 12tuyeres are not much different,being in the range of 2.24×10^(-4)-2.87×10^(-4)L/s.The volumetric mass transfer coefficients increase greatly with increase in bottom gas flowrate lower than 1.14m^(3)/h,while at the bottom gas flowrate greater than 1.14m^(3)/h,the volumetric mass transfer coefficient increases slowly.The average product of carbon and oxygen contents of molten steel at the end point during a whole of campaign was 0.00196×10^(-4)with the application of case of 12bottom tuyeres in an industrial combined blown converter.At different stages of the converter campaign,the average carbon and oxygen product was 0.00188×10^(-4)-0.00204×10^(-4).The ratio of the heats with the carbon and oxygen content product being less than 0.0025×10^(-4)reached 90.53%.