Quantification of blast furnace hearth drainage parameters through physical model study

Desai, Bobby; Lenka, S.

doi:10.1179/174328107x155321

Cited by 6 publications

(2 citation statements)

References 7 publications

(7 reference statements)

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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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“…Physical models of iron-producing blast furnaces have been reported, [2][3][4] used in model validations. The 2D and 3D computational fluid dynamics (CFD) approaches to model tapping from iron-producing blast furnaces have been reported, [2,4,5] which utilized the volume of fluid (VOF) method to represent the gas-liquid or slag-metal interfaces during tapping.…”

Section: B Previous Workmentioning

confidence: 99%

Modeling of Manganese Ferroalloy Slag Properties and Flow During Tapping

Muller

Zietsman

Pistorius

2015

Metall Mater Trans B

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Stable operation of submerged-arc furnaces producing high-carbon ferromanganese (HCFeMn) and silicomanganese (SiMn) requires tapping of consistent amounts of liquid slag and metal. Minimal effort to initiate and sustain tapping at reasonable rates is desired, accommodating fluctuations in especially slag chemical composition and temperature. An analytical model is presented that estimates the tapping rate of the liquid slag-metal mixture as a function of taphole dimensions, coke bed particulate properties, and slag and metal physicochemical properties with dependencies on chemical composition and temperature. This model may be used to evaluate the sensitivity to fluctuations in these parameters, and to determine the influence of converting between HCFeMn and SiMn production. The model was applied to typical HCFeMn and SiMn process conditions, using modeled slag viscosities and densities. Tapping flow rates estimated were comparable to operational data and found to be dependent mostly on slag viscosity. Slag viscosities were generally lower for typical SiMn slags due to the higher temperature used for calculating viscosity. It was predicted that flow through the taphole would mostly develop into laminar flow, with the pressure drop predominantly over the coke bed. Flow rates were found to be more dependent on the taphole diameter than on the taphole length.

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A review on liquid level measurement techniques using mathematical models and field sensors in blast furnace

Agrawal

Kothari

Ramna

et al. 2019

Metall. Res. Technol.

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Stable blast furnace operation requires proper drainage of liquid from the hearth. The estimation of drainage rate and hearth liquid level are of utmost importance for understanding the underlying hearth phenomena. The present review gives an insight of the need for measurement of the hearth liquid level and further throws light on various methods of estimation of hearth liquid level in-depth, which is primarily divided into 2 categories namely; model-based estimation and sensor-based estimation. Although the model-based estimation and sensor-based estimation have their own advantages and disadvantages, an integrated system comprising of both methods could potentially facilitate operators to reveal the state of hearth, which is unless not available with the implementation of a single method of estimation. Furthermore, the challenges in the estimation and the prospects for determining the reliable hearth liquid level measurement in blast furnace are discussed. The article is presented to give prospect of encountering the drift occurring in estimation of liquid level, which leads to inaccurate prediction and simulation with the industrial blast furnace. Lastly, the article gives recommendation for improving the liquid level estimation methods in blast furnace.

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Quantification of blast furnace hearth drainage parameters through physical model study

Cited by 6 publications

References 7 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

Modeling of Manganese Ferroalloy Slag Properties and Flow During Tapping

A review on liquid level measurement techniques using mathematical models and field sensors in blast furnace

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