Novel model for estimation of liquid levels in the blast furnace hearth

Brännbacka, Johnny; Saxén, Henrik

doi:10.1016/j.ces.2004.05.007

Cited by 36 publications

(38 citation statements)

References 14 publications

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“…When the tapping starts, i.e., when the taphole is drilled open, iron and slag flow out through the dead-man and taphole. Many researchers [1][2][3][4][5][6][7][8][9][10] have studied this complex system, primarily concentrating their efforts on analyzing the effects of inhearth conditions, such as coke diameter, dead-man voidage, and extent of the coke free region, on the drainage behavior. As for the conditions in the taphole, most of these studies assumed either a constant pressure loss or assumed iron and slag to be a mixture of specified volume ratio and applied mean values of density and viscosity in describing the flow.…”

Section: Introductionmentioning

confidence: 99%

A Simulation Study of Blast Furnace Hearth Drainage Using a Two-phase Flow Model of the Taphole

Shao

Saxén

2011

ISIJ Int.

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The drainage of the hearth plays an important role for the operation of the ironmaking blast furnace. An undisturbed extraction of the produced molten materials from the hearth is a prerequisite of a smooth operation of the high-temperature region, and a good mixing of liquid iron and slag in the taphole and runner helps desulfurize the iron. The flows of molten iron and slag in the blast furnace taphole have not received much attention, even though several investigators have studied the hearth drainage phenomena. In the present paper a two-fluid model of the taphole flow, based on an assumption of full stratification of the two liquids, is developed, and coupled with a simple material balance for the furnace hearth. Furthermore, the pressure loss of the liquids in the dead-man in front of the taphole inlet is considered. Simulations with the model are applied to illustrate how different factors affect the drainage, liquid levels and taphole flow. It is demonstrated that the in-furnace conditions play an important role for the flows and the flow distribution between iron and slag. The effects of key variables, such as coke-bed voidage and coke size, are illustrated and conclusions concerning their impact on the drainage are drawn.KEY WORDS: taphole; two-phase flow; hearth drainage; blast furnace.hearth drainage and taphole flow, paying special attention to the latter condition. A simultaneous flow of two immiscible liquids through a (slightly inclined) pipe is encountered in a variety of industrial processes, but usually the density and viscosity differences of the two liquids are not as big as for the molten materials in the BF taphole. Despite these differences, the model equations for fully stratified flow are known and can be rather readily applied to the present problem. [13][14][15][16] However, the pressure loss in the coke bed (dead-man) in front of the taphole for the two phases has also to be considered. The novelty of this work is to use a two-fluid (TF) model to describe the dynamic features of iron and slag flow in the taphole and to couple this with a simple description of the hearth drainage process. ModelingThe present study simulates the hearth drainage of a small or medium-size BF with a single taphole. According to the typical tap cycle, 17) the taphole is generally kept plugged for about 20-30 min to let the injected taphole mud solidify properly after the previous tapping operation. This section describes the main assumptions made in the modeling, as well as the arising equations of the model. Simplifying AssumptionsSince the conditions of dead-man and taphole are extremely complex during the tapping operation, some assumptions must be made in order to be able to simulate the tap cycle. The following simplifications are therefore introduced (where the 'iron level' and the 'slag level' refer to the overall vertical levels in the hearth of the iron-slag interface and the slag-gas interface, respectively): a) The dead-man sits at the bottom of hearth and its voidage is constant. b) The liquid v...

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Section: Introductionmentioning

confidence: 99%

A Simulation Study of Blast Furnace Hearth Drainage Using a Two-phase Flow Model of the Taphole

Shao

Saxén

2011

ISIJ Int.

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“…With the increase of the size of coke particle, the number of the large particle near the furnace wall, and the voidage of the coke bed, with the decrease of the slag viscosity, the interface will be lower and lower, the volume of residual slag will be less, but the space of free coke and the penetrability of the coke bed have no obvious effect on the interface height. The literature 49,61) showed that surface profile is parabola at the end of tapping, just like Fig. 4(a).…”

Section: Vof (Volume Of Fluid) Modelmentioning

confidence: 99%

Research Status and Development Trend of Numerical Simulation on Blast Furnace Lining Erosion

et al. 2009

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“…Such models, which are based on indirect measurements, provide interpretations of phenomena of interest and their use may lead to a deeper understanding of the internal state and the interrelations between variables. Models based on the assumption of a stationary or a floating dead man have been reported in the literature,6–10 and been applied to estimate liquid levels and tap rates. If short‐term information about the production and tap rates is available, mass balance equations of iron and slag in the hearth can be applied to estimate the instantaneous liquid volumes.…”

Section: Introductionmentioning

confidence: 99%

Model of Blast Furnace Hearth Drainage

Shao

Saxén

2011

steel research int.

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The hearth plays an important role in the operation of the ironmaking blast furnace (BF). A simplified simulation model of the hearth based on the general principles of liquid drainage has been extended to make the model more practical and comprehensive. The tap rates of the liquids are determined by production and taphole conditions, including taphole diameter and length, and the tap‐end conditions are iteratively calculated to yield a quasi‐stationary tap cycle. The model, which considers both a sitting and a (partially) floating dead man, is illustrated with the use of a set of examples, where the effect of variables on the drainage behavior is studied. The model is finally validated by applying it to short‐term data from an industrial BF.

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Novel model for estimation of liquid levels in the blast furnace hearth

Cited by 36 publications

References 14 publications

A Simulation Study of Blast Furnace Hearth Drainage Using a Two-phase Flow Model of the Taphole

A Simulation Study of Blast Furnace Hearth Drainage Using a Two-phase Flow Model of the Taphole

Research Status and Development Trend of Numerical Simulation on Blast Furnace Lining Erosion

Model of Blast Furnace Hearth Drainage

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