Effects of Particle Free Space on Hearth Drainage Efficiency.

Nouchi, Taihei; Yasui, Masato; Takeda, Kanji

doi:10.2355/isijinternational.43.175

Cited by 41 publications

(51 citation statements)

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“…Nouchi et al examined the effect of particle free space on hearth drainage efficiency by using immiscible two different density fluids. 6) They reported the coke free zone in front of the taphole drastically changed the residual slag volume in the hearth. However, the effect of other in-furnace conditions for examples, slag viscosity, iron and slag density has not been examined because immiscible appropriate liquids for their experiment are limited.…”

Section: Introductionmentioning

confidence: 99%

“…Especially, the slag flow behavior should be understood precisely. [1][2][3][4][5][6][7] Fukutake and Okabe proposed 'flow out coefficient', F L , and they concluded that their correlation can be used to estimate residual slag volume in a blast furnace. [1][2][3] At the same time, the effect of the iron phase below the taphole was not considered.…”

Section: Introductionmentioning

confidence: 99%

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A Three-dimensional Mathematical Modelling of Drainage Behavior in Blast Furnace Hearth

2005

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Stable blast furnace operation is required to reduce energy consumption in iron and steelmaking industry. For the stable blast furnace operation, precise controlled drainage is one of the important factors. However, the effects of the various in-furnace conditions on the stable operation were not examined well. Therefore, in this work, basic characteristic features of drainage in a blast furnace hearth were examined.Two-and three-dimensional mathematical model were developed based on the finite difference method to simulate molten iron and slag flow in a hearth of a blast furnace. Pressure drop evaluation model in a taphole was developed to reflect pressure variation in a blast furnace hearth on drainage rate of molten iron and slag for the three-dimensional mathematical model.The two-dimensional mathematical model results were validated with measured interfaces shapes obtained using an experimental model. The three-dimensional mathematical model results were validated with measured total, iron and slag drainage rate of Chiba No. 6 blast furnace. The results indicate that the drainage behavior and residual iron and slag volume were affected by the conditions in the hearth. The taphole conditions dominate the total drainage rate under the term of assumed blast furnace conditions. In order to reduce the residual slag volume, the taphole diameter change during the tap should be controlled. The decrease of the coke diameter causes increase of the residual slag volume, decrease of the residual iron volume.KEY WORDS: iron and slag flow; residual slag volume; numerical simulation; VOF method; blast furnace hearth; ironmaking.faces shapes of immiscible fluids having different properties. Two-dimensional Mathematical ModellingThe governing equations for fluid flow used in the twodimensional mathematical model are based on the HSMAC method, 8) ... (3) where u is the horizontal velocity (m/s), v is vertical velocity (m/s), x and y are coordinates (m), t is time (s), r is density of fluids (kg/m 3 ), p is pressure of fluids (Pa), m is viscosity (Pa · s), g is acceleration due to gravity (m/s 2 ), and S is an interaction force between fluid and 2 flat parallel plates (m/s 2 ). In the two-dimensional mathematical model, gas, slag and iron were treated as one fluid having local properties, which correspond to each phase. Representation of InterfacesFor the determination of the fluid properties in each computational cell, it is necessary to compute the proportion of gas, iron and slag in each cell. Therefore, gas-slag and slag-iron interfaces should be identified exactly. To distinguish the interfaces, the VOF method 9) was applied for the calculation of interfaces (gas-slag, slag-iron). Generally, the VOF method is used to track free boundaries in two-or three-dimensional meshes. Although, in this work, VOF is also used to identify slag-iron interface, as shown in Fig. 1. A unit value of VOF 1 would correspond to a cell full of liquid. A unit value of VOF 2 would correspond to a cell full of iron. Cells with VOF 2 values betw...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Three-dimensional Mathematical Modelling of Drainage Behavior in Blast Furnace Hearth

2005

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“…An efficient and strictly controlled tapping is necessary for guaranteeing a stable operation and high productivity of the BF. Many recent investigations [1][2][3][4][5][6][7][8][9] on this subject have revealed that the pressure drop caused by fluid flow through the deadman in the hearth is a significant factor governing hearth drainage. However, due to the hostile environment, the possibilities to directly measure internal variables are practically nonexistent.…”

Section: Introductionmentioning

confidence: 99%

Pressure Drop in the Blast Furnace Hearth with a Sitting Deadman

Shao

Saxén

2011

ISIJ Int.

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“…the formation of coke free zone, affects the liquid drainage. 34,35,44,45) The flow of particles in the hearth is mainly driven by the downward gravitational and upward buoyancy forces, and hence strongly affected by the level of liquid and the position of discharging hole due to the upward buoyancy forces. 34) An attempt was recently made by Nouchi et al 35) to simulate the solid flow in BF hearth and reveal the formation mechanisms of dead zone.…”

Section: Solid Flow In the Hearthmentioning

confidence: 99%

Numerical Investigation of the Transient Multiphase Flow in an Ironmaking Blast Furnace

Zhou

Zhu

et al. 2010

ISIJ Int.

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Discrete particle simulation (DPS) has been applied to multiphase flow modelling in an ironmaking blast furnace (BF), including burden distribution at the top, gas-solid flow in the BF shaft and raceway, and liquid-solid flow in the hearth. In this work, the approach is further extended to take into account the transient features of gas and particle flow coupled with liquid tapping operation. In the simulation, two types of particles of coke and ore with different physical properties are considered, together with different shapes of the cohesive zone and the shrinkage of size of ore particles in the cohesive zone to present ore reduction. The simulated results show that the flow of both solid and gas phases varies spatially and temporally, particularly in the cohesive zone. Gas flow is strongly affected by the layered structure of ore and coke particles in the cohesive zone. A coke-free zone can form in the hearth, and the boundary profile between the coke-free zone and the coke bed depends on the amount of liquid accumulated in the hearth, gas and solid flow rates in the raceway, and coke consumption in different regions at the interface of liquid and the coke bed. The results show that the complicated transient multiphase-flow in a BF can be captured by the present approach which may be extended to account for heat transfer and chemical reaction in the future.KEY WORDS: multiphase flow; discrete particle simulation; computational fluid dynamics; blast furnace; cohesive zone. 515

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Effects of Particle Free Space on Hearth Drainage Efficiency.

Cited by 41 publications

References 2 publications

A Three-dimensional Mathematical Modelling of Drainage Behavior in Blast Furnace Hearth

A Three-dimensional Mathematical Modelling of Drainage Behavior in Blast Furnace Hearth

Pressure Drop in the Blast Furnace Hearth with a Sitting Deadman

Numerical Investigation of the Transient Multiphase Flow in an Ironmaking Blast Furnace

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