Formation and Melt-Down of Softening-Melting Zone in Blast Furnace

Sasaki, Minoru; Ono, Kazuyoshi; Suzuki, Akira; Okuno, Yoshio; Yoshizawa, Ken-ichi; Nakamura, Takashi

doi:10.2355/tetsutohagane1955.62.5_559

Cited by 30 publications

(16 citation statements)

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“…With reference to the work done by Gudenau et al [22,23] and Bakker et al, [44] Fig. 1-Schematic shows the (a) internal state of the cohesive zone [42] ; (b) temperature-based definition of the nonlayered cohesive zone; and (c) defined layered cohesive zone. Note that T s refers to solid phase temperature even for the solid which is in the melting state.…”

Section: Cz Treatmentsmentioning

confidence: 99%

“…Physically, the CZ may be subdivided into the following different states as shown in Figure 1(a) [42] : molten, softening, lumpy, and coke-only. According to the analysis of Kanbara et al, [43] in Figure 1(a), distributions of metallic iron and slag were present, whereas in Figure 1(b), iron-bearing materials were about 70 pct reduced and bonded together.…”

Section: Cz Treatmentsmentioning

confidence: 99%

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Modeling of Blast Furnace with Layered Cohesive Zone

Dong

Chew³

et al. 2010

Metall Mater Trans B

124

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An ironmaking blast furnace (BF) is a moving bed reactor involving counter-, co-, and crosscurrent flows of gas, powder, liquids, and solids, coupled with heat exchange and chemical reactions. The behavior of multiple phases directly affects the stability and productivity of the furnace. In the present study, a mathematical model is proposed to describe the behavior of fluid flow, heat and mass transfer, as well as chemical reactions in a BF, in which gas, solid, and liquid phases affect each other through interaction forces, and their flows are competing for the space available. Process variables that characterize the internal furnace state, such as reduction degree, reducing gas and burden concentrations, as well as gas and condensed phase temperatures, have been described quantitatively. In particular, different treatments of the cohesive zone (CZ), i.e., layered, isotropic, and anisotropic nonlayered, are discussed, and their influence on simulation results is compared. The results show that predicted fluid flow and thermochemical phenomena within and around the CZ and in the lower part of the BF are different for different treatments. The layered CZ treatment corresponds to the layered charging of burden and naturally can predict the CZ as a gas distributor and liquid generator.

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Section: Cz Treatmentsmentioning

confidence: 99%

Section: Cz Treatmentsmentioning

confidence: 99%

Modeling of Blast Furnace with Layered Cohesive Zone

Dong

Chew³

et al. 2010

Metall Mater Trans B

124

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“…In observation of the cohesive zone in dissected blast furnaces such as Hirohata No. 1 blast furnace 15) and Jenice No. 2 blast furnace, 16) there were icicle-like semi-molten materials extending from the bottom of the cohesive zone into the coke layer.…”

Section: Pressure Drop In Layered Conditionmentioning

confidence: 99%

Evaluating Effect of Coke Layer Thickness on Permeability by Pressure Drop Estimation Model

Ichikawa¹,

Kashihara²,

Oyama³

et al. 2017

ISIJ International

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Recently, low coke rate blast furnace operation has been required in response to the rising cost of coking coal. However, the thickness of the coke layer decreases in low coke rate operation. Since it is known that the gas permeability of the blast furnace deteriorates as the coke layer thickness decreases, it is important to determine the minimum coke layer thickness for stable blast furnace operation. On the other hand, the minimum coke layer thickness has not been clarified due to a lack of equipment capable of measuring the effect of the coke layer thickness on permeability.In this study, a new experimental device called the cohesive zone simulator was developed to clarify the minimum coke layer thickness. In the cohesive zone, gas flows horizontally along the coke layer. In order to quantify the effect of the coke layer thickness on permeability, this horizontal gas flow should be simulated. Therefore, this simulator simulates a horizontal gas flow.Next, the effect of the coke layer thickness was quantified by using the cohesive zone simulator. The results showed that melting iron ore penetrated into the coke layer and closed part of the layer. These phenomena caused a deterioration of permeability under thin coke layer thickness conditions. Finally, a pressure drop estimation model considering penetration of the coke layer by melting ore was developed with the aim of quantifying the minimum coke slit thickness.

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“…1, after descending in an icicle-like form from the cohesion zone, it is considered that the melt repeatedly disperses and coalesces as it drips through the coke packed bed. 8) This initial dripping of the melt and the subsequent motion of the droplets was the focus of the present study. Figure 2 shows the concept of the MPS method.…”

Section: Introductionmentioning

confidence: 99%

“…Directly under the cohesion zone, the melt drips in an "icicle" form. 8) Below this point, observation in cold experiments, etc. suggests that the liquid flow phenomenon comprises various phenomena, such as branching and coalescence of flow paths, which are collections of droplets, deformation of droplets, and the like.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Dripping Behavior of Droplet in Packed Bed Using Particle Method

et al. 2012

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The liquid flow in the packed bed strongly affects the productivity and operational stability of the blast furnace. It is controlled by the physical properties and wettability of the melt and the structure of the packed bed. However, this is a difficult object of analysis, as melt properties and conditions in the furnace are inhomogeneous. In this research, a three-dimensional model of the liquid flow in a packed bed was constructed using the MPS method, which is one of particle method, in order to express melt behavior. The liquid flow on solid surfaces was expressed by optimizing the relationship of energy at a three-phase (solid, gas, liquid) interface. The appropriateness of the calculation model was verified by analyzing and comparing the behaviors of liquids with different physical properties flowing on the surface of a single sphere experimentally and in calculations. Next, this model was applied to analysis of the flow of liquids dripping in a packed bed, and a simulation was calculated for a three-dimensional liquid flow comprising dispersion and coalescence of the liquid. Among the knowledge obtained in this study, the viscosity of a liquid migrating through a packed bed influences the velocity and flow path of the liquid, but has little effect on the amount of liquid which remains in a static condition in the packed bed.

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Formation and Melt-Down of Softening-Melting Zone in Blast Furnace

Abstract: The processes of formation and melt-down of the softening-melting zone are discussed based on the results of dissection of water-quenched blast furnaces.

Cited by 30 publications

References 0 publications

Modeling of Blast Furnace with Layered Cohesive Zone

Modeling of Blast Furnace with Layered Cohesive Zone

Evaluating Effect of Coke Layer Thickness on Permeability by Pressure Drop Estimation Model

Numerical Simulation of Dripping Behavior of Droplet in Packed Bed Using Particle Method

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