(71d) Mixed Layer Formation in a Blast Furnace and Its Effect on the Performance

Dianyu E,^1[*] Qinfu Hou,¹ and Aibing Yu^1,2

¹ARC Research Hub for Computational Particle Technology, Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia

²Centre for Simulation and Modelling of Particulate Systems, Southeast University - Monash University Joint Research Institute, Suzhou 215123, PR China

Abstract

Gas flow distribution in a blast furnace (BF) plays a significant role in BF smooth operation, productivity and thermal efficiency. It is affected by the distribution of burden materials composed of alternating coke and ferrous ore layers. While moving downward coke and ferrous layers of different sizes can mix and form the so-called mixed layers. Generally, the porosity is lower and hence the pressure drop is higher in the mixed layers. These variations can change the gas flow distribution and BF performance. Previous work tried to quantify the effect of material properties and process conditions on the formation of mixed layers and the resulting local porosity variation. However, these studies were often conducted under simplified conditions. Few was dedicated to the formation of mixed layers in a BF and its effect on BF performance. This work studies the formation of mixed layers in an experimental BF by using a combined computational fluid dynamics and discrete element method approach. The effect on BF performance is evaluated under different operational conditions including different size ratios of coke and iron ore particles, burden distribution and batch weight, and discharge rates. The results are helpful to optimize burden charge for improving BF performance.

Keywords: Blast furnace, Mixed layer, Discrete element method, Computational fluid dynamics