COREX竖炉螺旋结构对物料运动影响的DEM模拟

Effect of Screw Structure on Burdens Moving Behavior in COREX Shaft Furnace with DEM Simulation

基于离散单元方法建立了三维COREX-3000竖炉模型,通过模拟研究比较了宝钢螺旋与设计的均匀下料螺旋的下料均匀性指数、物料流型和物料下降速度在炉内的分布.结果表明,宝钢螺旋的下料均匀性指数在第1节到第5节螺旋上都较小,最大值在第4节螺旋上为0.36,而设计螺旋的下料均匀性指数在整个下料段都接近1,在理论上达到了均匀下料的目的;从宏观上看,设计螺旋在整个竖炉高度上的物料流型比宝钢螺旋更均匀;在围管下方设计螺旋沿竖炉径向的下料速度比宝钢螺旋均匀,在围管上方螺旋结构对物料下降速度的影响很小,下料模式接近活塞流.

A COREX-3000 shaft furnace model was established based on discrete element method to compare the drawdown uniformity coefficient,drawdown pattern and distribution of descending velocity between Baosteel screw and the newly designed screw by means of simulating. The results show that the drawdown uniformity coefficients of Baosteel screw from pitch 1 to pitch 5 are small and the peak 0. 36 appears at pitch 4. However,the drawdown uniformity coefficients of the newly designed screw are close to 1 in all the burden drawdown area. From the macroscopic aspect,the drawdown patterns of the new screw along the whole height of shaft furnace are more uniform than that of Baosteel screw. Below the gas slots,the distribution of descending velocity along the radius of the shaft furnace with the new screw are more uniform than that with Baosteel screw. Above the gas slots,the effect of screw structure on burden descending velocity is small, and the drawdown patterns is more like plug flow.