Burden Distribution Analysis by Digital Image Processing in a Scale Model of a Blast Furnace Shaft.

Jiménez, Juan José de la Vega; Mochón, Javier; Formoso, A.; Ayala, Jesús Sainz de

doi:10.2355/isijinternational.40.114

Cited by 38 publications

(40 citation statements)

References 4 publications

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“…Four flow regions have been identified in the BF shaft 6,61,62) : plug flow at the top part where uniform velocity occurs; stagnant zone (deadman) in the center of the lower part where particles are often regarded as static; quasi-stagnant zone, adjacent to the deadman, where particles move very slowly; and converging flow region where particles have a significant velocity variation between the furnace wall and stagnant zone. There have been numerous physical modelling studies undertaken on burden distribution, [63][64][65][66] solid flow pattern 6,61,62,67) and stress state. 68) These studies have both improved our understanding of the macroscopic features of solid flow and provided data with which to validate numerical models.…”

Section: Bf Shaftmentioning

confidence: 99%

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

et al. 2007

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An ironmaking blast furnace is a complex multiphase flow reactor involving gas, powder, liquid and solid phases. Understanding the flow behaviour of these phases is of paramount importance to the control and optimization of the process. Mathematical modelling, often coupled with physical modelling, plays an important role in this development. Yagi 1) gave a comprehensive review of the early studies in this area in 1993. Significant progress has since been made, partially driven by the needs in research but mainly as a result of the rapid development of computer and computational technologies. This paper reviews these developments, covering the formulation, validation and application of mathematical models for gas-solid, gas-liquid, gas-powder and multiphase flows. The need for further developments is also discussed.KEY WORDS: ironmaking; blast furnace; multiphase flow; two fluid model; discrete element method. Review development. Mathematical ModellingGenerally speaking, the existing approaches to modelling the multiphase flow in a BF can be classified into two categories: continuum approach at a macroscopic level and discrete approach at a microscopic level. In the continuum approach, phases are generally considered as fully interpenetrating continuum media and described by separate conservation equations with appropriate constitutive relations and interaction terms representing the coupling between phases. The general governing equations are based on the so-called two fluid model (TFM), originally developed for gas-particle flow, [29][30][31] given by:Conservation The so-called Model A and Model B result from the treatment of the fluid pressure. For example, for gas-solid flow, Model A assumes the pressure is shared between the two phases, while in Model B, the pressure is attributed to gas phase only. 31) Model A formulation has been widely used in multiphase modelling, especially in process metallurgy. Model B formulation was recently used in the so called combined continuum and discrete method for coupled flow of continuum fluid and discrete particles. 32) The continuum approach is suitable for process modelling and applied research because of its computational convenience and efficiency. Indeed, most of the BF modelling is based on this approach. However, its effective use heavily depends on constitutive or closure relations and the momentum exchange between phases. For Newtonian fluids (gas and liquid here), these relations can be readily determined. For non-Newtonian fluids such as solids and powder, general theories are not yet available. In the past, various theories have been devised for different flow regimes (three flow regimes have been identified: quasi-static regime, rapid flow regime and a transitional regime that lies inbetween). For example, models have been proposed to derive the constitutive equations for the rate-independent deformation of granular materials based on either the plasticity theory or the double shearing theory; the rapid flow of granular materials has been described by extend...

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Section: Bf Shaftmentioning

confidence: 99%

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

et al. 2007

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“…Furthermore, in the actual blast furnace, the coke layer thickness after collapse cannot be measured because the coke layer is covered with ore layer. Since many experimental studies have been carried out to investigate the coke collapse and clarify dominant factors [1][2][3][4][5][6]. Some studies have used numerical method like Discrete Element Method (DEM) [7] for better understanding of the phenomena involved.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Coke Layer Collapse during Ore Charging in Ironmaking Blast Furnace by DEM

Narita¹,

Mio²,

Orimoto³

et al. 2017

EPJ Web Conf.

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Abstract.A technical issue in an ironmaking blast furnace operation is to realize the optimum layer thickness and the radial distribution of burden (ore and coke) to enhance its efficiency and productivity. When ore particles are charged onto the already-embedded coke layer, the coke layer-collapse phenomenon occurs. The coke layer-collapse phenomenon has a significant effect on the distribution of ore and coke layer thickness in the radial direction. In this paper, the mechanical properties of coke packed bed under ore charging were investigated by the impact-loading test and the large-scale direct shear test. Experimental results show that the coke particle is broken by the impact force of ore charging, and the particle breakage leads to weaken of coke-layer strength. The expression of contact force for coke in Discrete Element Method (DEM) was modified based on the measured data, and it followed by the 1/3-scaled experiment on coke's collapse phenomena. Comparing a simulation by modified model to the 1/3-scaled experiment, they agreed well in the burden distribution.

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“…12,13) It is hard to ascertain the effect of the charging a layer on the underlying layers as it is difficult to measure the underlying profile after the new layer has been charged. Some studies have used magnetometer readings 14) or image processing techniques 8,15) for experimental verification, but these method have their own drawbacks: magnetometer is intrusive disturbing the layer structure and image processing requires a furnace section with a transparent wall, which induces wall effects. Therefore some studies have resorted to sophisticated numerical techniques like Discrete Element Modeling (DEM) for better understanding of the phenomena involved.…”

Section: Introductionmentioning

confidence: 99%

“…Coke collapse has been observed both in numerical studies 1,7) and experimentally. 8,9) Various schemes have been suggested to prevent the collapse, for example creating a coke plateau near the wall and controlling the particle trajectory. 10,11) Some other schemes have used it to their advantage to achieve a central working furnace.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Coke Collapse in the Blast Furnace Using Mathematical Modeling and Small Scale Experiments

Mitra

Saxén

2016

ISIJ International

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Burden distribution plays a key role in controlling the gas flow conditions inside a blast furnace. The distribution of ore and coke influences the gas permeability distribution in the lumpy zone and also in the cohesive zone, where the gas flows mainly through the coke slits. Charging an ore dump on coke can sometimes cause the coke layer to collapse under the force of the heavier ore particles. This is known as 'coke collapse' or 'coke push', which results in a higher coke fraction near the center of the furnace than expected. In this work coke collapse phenomena are evaluated on model charging programs using small scale experiments and Discrete Element Modeling (DEM). DEM simulations were used to study the extent of collapse for different charging programs, and experiments were undertaken to verify the results of the simulations. The slope stability method was used to classify the collapse conditions into no collapse, impact failure or gravity failure, depending on the stability of the coke layer. The findings were also compared with results from an in-house mathematical model, which was modified to consider the effect of the collapse on the underlying layer. The corrected mathematical model was found to show results in general agreement with results from the DEM simulation.

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Burden Distribution Analysis by Digital Image Processing in a Scale Model of a Blast Furnace Shaft.

Cited by 38 publications

References 4 publications

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

Modelling of Coke Layer Collapse during Ore Charging in Ironmaking Blast Furnace by DEM

Investigation of Coke Collapse in the Blast Furnace Using Mathematical Modeling and Small Scale Experiments

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