Modelling of Multiphase Flow in Ironmaking Blast Furnace

Abstract

A mathematical model for the four-phase (gas, powder, liquid, and solids) flow in a two-dimensional ironmaking blast furnace is presented by extending the existing two-fluid flow models. The model describes the motion of gas, solid, and powder phases, based on the continuum approach, and implements the so-called force balance model for the flow of liquids, such as metal and slag in a blast furnace. The model results demonstrate a solid stagnant zone and dense powder hold-up region, as well as a dense liquid flow region that exists in the lower part of a blast furnace, which are consistent with the experimental observations reported in the literature. The simulation is extended to investigate the effects of packing properties and operational conditions on the flow and the volume fraction distribution of each phase in a blast furnace. It is found that solid movement has a significant effect on powder holdup distribution. Small solid particles and low porosity distribution are predicted to affect the fluid flow considerably, and this can cause deterioration in bed permeability. The dynamic powder holdup in a furnace increases significantly with the increase of powder diameter. The findings should be useful to better understand and control blast furnace operations.

Basic Characteristics of the Shaft Furnace of COREX® Smelting Reduction Process Based on Iron Oxides Reduction Simulation

“…However, with the development of computational fluid dynamic, numerical methodology has been widely used in simulating metallurgical iron-making processes, such as traditional blast furnace process [7][8][9][10][11][12][13] and latest Midrex ® process. [14][15][16] Although the role of COREX ® shaft furnace plays is similar with that of lump zone in blast furnace, there are some differences existed between them in term of initial reducing gas composition, distribution and temperature, as well as burden distribution pattern.…”

Preliminary Investigation on the Capability of eXtended Discrete Element Method for Treating the Dripping Zone of a Blast Furnace

“…2,18,49) The permeability of the gas phase and liquid phases hold up, which govern the flow of gas and liquid phases, are key factors to smooth and stable blast furnace operation. These parameters are highly sensitive to the porosity distribution.…”

“…This capability makes the current method close to the reality compared to other studies with the assumption of constant porosity distribution. 1,2) The liquid hold up reported in this study is the resultant of the particles drag force and gravitational force without taking into account the capillarity effects. The importance of capillary pressure on the liquid hold up in packed is non-negligible.…”

“…This model gives more detailed information for the distribution of the liquid phases through packed bed of coke particles at different gas velocities, which cannot be realized by the continuous methods. Almost all continuous methods either use constant porosity distribution 1,2) or benefit the correlation 13,40) for porosity calculation, while the XDEM itself calculates the porosity distribution by considering the position of the particles. Although this model has the capacity to consider several liquid phases, in the current study the validation was done solely for one liquid phase.…”

Mathematical Model of Solid Flow Behavior in a Real Dimension Blast Furnace

“…The continuum approach assumes that all the phases in the furnace behave like a continuum medium and is based on a local average principle. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] On the other hand, the discrete method is based on the Newton's second law of motion and is focused on the behavior of each and all individual particles in the system. [22][23][24][25][26][27][28][29][30] The discrete element method (DEM) is originally developed by Cundall and Strack 31) and is very effective to model granular materials.…”