竖冷炉内烧结矿分布的DEM模拟

DEM simulation of sinter distribution in vertical cooling furnace

为研究竖冷炉料层透气性以改善冷却气体分布,建立梅钢竖冷炉单料仓扁平模型,采用离散单元法模拟研究了竖冷炉布料和排料过程,获得了稳态下竖冷炉内烧结矿分布和孔隙率分布的微观信息。结果表明,布料时由于落料点位置的变化,烧结矿会产生偏析分布。在烧结矿流动稳定的状态下,炉腔存在准静止区、活塞流区和汇聚流区3种流动区域;就烧结矿分布而言,炉腔中心区含有更多的10~25 mm和25~40 mm颗粒,炉腔中间区则分布有更多的40~80 mm和80~150 mm颗粒,炉腔边壁区中上部25~40 mm和40~80 mm颗粒的质量分数更高,而下部80~150 mm的颗粒质量分数更高。上述烧结矿分布使炉腔边壁区和中间区发生大颗粒偏析,炉腔中心区发生小颗粒偏析;孔隙率呈炉腔边壁区和中心区较大、中间区较小的“U”形分布。料层透气性在边壁区最好,导致冷却气体易从边壁区逸出。为改善冷却气体在炉内的分布,可尝试从缩小入炉烧结矿粒度范围以及开发新型布料装置展开进一步研究。

In order to study the permeability of sinter in vertical cooling furnace and improve the distribution of cooling gas,the slot model of single bin for vertical cooling furnace in Meigang was established.The charge and discharge process were simulated by discrete element method.Sinter and its porosity distribution in the vertical cooling furnace under steady-state conditions were obtained.The results show that during charging,the segregation distribution of sinter will occur due to the change of landing point.When the sinter flow is stable,there are three flow regions in the furnace cavity,quasi stationary region,mass flow region and convergent flow region.In terms of sinter distribution,the central area of furnace cavity contains more particles of 10-25 mm and 25-40 mm.More particles of 40-80 mm and 80-150 mm are distributed in the middle area.In the middle and upper part of the sidewall area,the mass fraction of 25-40 mm and 40-80 mm particles are higher,while the mass fraction of 80-150 mm particles in the lower part is higher.Such sinter distribution causes large particle segregation in the sidewall area and middle area of the furnace cavity,and small particle segregation in the center area.The porosity is distributed as"U"with larger in sidewall as well as central area,and smaller in middle area.Sinter in the sidewall area has the best air permeability,resulting in the easy escape of cooling gas from the sidewall area.In order to improve the distribution of cooling gas in the furnace,further research could be carried out from reducing the sinter size range and developing a new charge device.