炉料粒度对高炉料面炉料分布及透气性的影响

Effect of particle size on burden distribution of stock surface and permeability of burden layer in blast furnace

为了研究炉料粒度对炉喉内炉料分布和料层透气性的影响,建立了4070m-3高炉并罐式无钟炉顶三维模型,应用离散单元法对炉料粒级分布为25-40、40-60和60-80mm时,炉料从料仓运动至炉喉全过程进行数值计算。结果表明,不同粒级分布的炉料在炉喉内形成的料层,其周向各区域内炉料体积分布均在±10%之间波动。随着颗粒粒度增大,料面堆尖位置沿圆周分布更接近圆形。颗粒粒度越小时,壁面效应作用越弱,边缘处空隙度相对于料面中心来说差别越小。对于25-40、40-60和60-80mm粒级炉料,边缘透气度分别是料面中间区域的1.4、2.1和2.5倍左右。因此,保证料面径向颗粒粒度合理分布,对料层透气性十分重要。

In order to investigate the effect of particle size on burden distribution and bed permeability, the calculated model of bell-less top system with two parallel hoppers used in a 4070 m-3 blast furnace was established. The motion of burden particles with different particle size distribution（PSD） included 25-40, 40-60 and 60-80 mm from bunker to throat was calculated by discrete element method. The results show that the volume of burden can fluctuate in the range of ±10% according to the circumferential area with different particle sizes. As the particle size increases, the tip position of the stock surface is closer to the circle along the circular distribution. The permeability of border is larger than that of the center of stock surface due to the wall effect, which is easy for gas overdevelop in border. With the decreases in particle size, the influence of wall effect is also weakened and the disparity in the voidage between border and center is reduced. Based on the calculated results obtained in this study, the permeability index of border is 1.4, 2.1, 2.5 times larger than that of the center for the 25-40, 40-60, 60-80 mm PSD. If the big particles are distributed near the wall, it is easy for gas overdevelop in border, then will have bad influence on blast furnace. Thus, keeping the radial distribution of particle size in burden surface is very important for bed permeability of burden layer.