DEM simulation of particle descending velocity distribution in the reduction shaft furnace

Abstract

-Reduction shaft furnace is a promising alternative to blast furnace ironmaking. The particle descending velocity distribution has a great influence on the shaft furnace, which directly affects the production index and further the shaft furnace normal smelting. Therefore, a three-dimensional model (3D) is established based on the discrete element method (DEM) and computation fluid dynamic (CFD). The effect of the gas flow in the shaft furnace, the height, the diameter and the bosh angle of the shaft furnace on the particle descending velocity distribution during discharging process is investigated by the model and analyzed based on the granular dynamic theory and Janssen theory. The results show that the particle velocity reduces along the radius. The effect of the gas flow on the velocity distribution is insignificant. In order to obtain a uniform velocity distribution, it is better to increase the height, or the diameter, or to decrease the bosh angle. An improved model is proposed for the uniform velocity distribution at last.B ecause of its fast reduction rates, consistent product quality, minimal environmental impacts, and great flexibility, reduction shaft furnace is a promising alternative to blast furnace ironmaking [1]. In the shaft furnace production, iron ore particles are charging in the shaft furnace, and the reducing gas having high temperature is blown from tuyeres, then the particles are reduced during descending. If the particle descending velocity distribution is not reasonable, the iron ore particles will not be reduced better, causing the production index decreases and further affecting the shaft furnace normal smelting. Consequently, it is necessary to focus on researching the particle descending velocity distribution in the shaft furnace.Hence many researches had been investigated about the solid flow [2-6], these results are helpful for an overall understanding of the solid flow. To sum up, there have been two approaches adopted for the solid flow research, such as the physical simulation [2][3][4] and the mathematical simulation [5,6]. Compared with the mathematical simulation, the physical simulation is hard to analyze the solid flow quantificationally. Kou et al. [5] researched the effect of the bottom diameter of COREX shaft furnace, the cylinder height and the screw flight diameter on the particle velocity distribution based on DEM. However, the model he developed is not taken into account the effect of the gas flow in the shaft furnace, the height, the diameter and the bosh angle of the shaft furnace on the particle descending velocity.Numerical simulation analysis for solid flow in shaft furnace is a useful tool to understand the behavior of solid flow. So far, DEM has become one of the most powerful simulation methods for granular behaviors. In the ironmaking field, many researches [5][6][7][8] had been studied about the granular behavior based on DEM, and the simulation results coincided well with the experiments and industrial operation. It can be found that DEM is well ...

Influence of Wall Angle of Direct Reduction Shaft Furnace on Particle Flow Pattern by DEM Modeling

“…The intricate fluid dynamics associated with granular flows have been extensively investigated. [12][13][14][15][16] Wu et al [17] performed an experimental and theoretical investigation of the flow characteristics of solid particles within a 2D moving bed. Their study revealed that factors such as the shape, size, and rest angle of the solid particles have a significant impact on the resulting flow pattern.…”

Influence of Lump Ore Ratio and Shapes on the Particle Flow Behavior Inside the Direct Reduction Shaft Furnace by Discrete Element Modeling Model

“…[9] Since the shape of lump ore is nonspherical and random, and the difference in shape will affect the charge compliance to a great extent, it is necessary to consider the difference in charge distribution and movement behavior in the shaft furnace due to the shape of the lump ore. Currently, the discrete element method (DEM) has been widely used to study the basic solid flow behavior in iron-making processes such as blast furnace, [10][11][12] smelting processes such as COREX, [13][14][15][16] and direct reduction processes such as MIDREX. [7] In addition, in a previous study, Yu et al [17] verified that DEM can predict the flow of irregular and spherical particles.…”

Solid Flow in a Shaft Furnace in Smelting Reduction Process under Circumferential Imbalance Conditions

“…This method can generate detailed microdynamic information of individual particles, such as particle velocity and interaction forces between particles, which is key for understanding the flow of burden materials in ironmaking process. Thus, DEM has been applied to study solid flow in a shaft furnace in smelting reduction process, such as dynamic burden distribution, particle descending velocity, effect of screws on solid flow, and the effect of Areal Gas Distribution (AGD) beams on solid flow . These studies provide useful information on solid flow in shaft furnace.…”