关键词: 串罐式无钟炉顶, 离散单元法, 粒度偏析, 石盒, 炉料运动

Abstract: A full model of serial-hopper bell-less type charging system of blast furnace was developed, and the movement of burden from conveyor to throat was calculated by discrete element method. Particle size segregation on the conveyor and in the upper and lower hoppers was studied, and the effects of installed stone box on burden distribution in the hopper, particle movement during charging and discharging and the size variation of discharged particles were analyzed. The results show that the small particles percolate into the lower material layer on the conveyor, which results in the average size of lower particles being smaller than that of the upper. Particle segregation exists in the vertical, circumferential and radial directions of upper hopper, and in the vertical and radial directions of lower hopper. However burden distribution in the circumferential direction of lower hopper is uniform, and the standard deviation of relative particle size is about 0.03. Installing stone box has little effect on burden distribution in the circumferential and vertical directions of hopper, however, the effect of stone box on burden distribution in the radial direction of hopper is large, since the small particles percolate near the stone box. The material surface is level and particles move in plug flow in the lower hopper with stone box, but burden surface forms heap tip and particles move in funnel flow without stone box. Change in mean size of discharged particles is affected by particle movement and burden distribution in the lower hopper. When stone box is not installed in hoppers, standard deviation of the size variation in discharging process is 7.15, and that is 10.42 with stone box and the change of discharged particle size is more obvious

Key words: serial-hopper bell-less top, discrete element method, size segregation, stone box, particle movement