A study on liquid flow in the blast furnace hearth

Brännbacka, Johnny; Torrkulla, J.; Saxén, Henrik

doi:10.1016/s1474-6670(17)37002-7

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…Such studies 12) along with CFD simulations by the present authors 13) indicate that it is reasonable to assume that the iron-slag interface during the tap is horizontal until it reaches the taphole level and slag starts to flow out. Therefore, the iron level in the hearth is "measured" once at every tap, and the moment when slag first enters the runner indicates the time, t k , when the iron level passes the taphole level on its descent during the tap.…”

Section: Modeling the Iron Levelmentioning

confidence: 52%

Mathematical Modeling of Iron and Steel Making Processes. Modeling the Liquid Levels in the Blast Furnace Hearth.

Brännbacka

Saxén

2001

ISIJ International

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The drainage of a blast furnace hearth is analyzed on the basis of measurements of the instantaneous mass flow rates of tapped iron and slag, obtained from radar level measurements in the iron ladles and a pressure signal from the slag granulation drum. The measurements are used in a model estimating the levels of liquids in the blast furnace hearth, where correction terms have been introduced to prevent the level estimates from excessive drift. When applying the model on data from two Finnish blast furnaces, it was found that the estimated iron level exhibited strong correlation with the electromotive force (emf ) measured between two electrodes at the furnace shell. The results of the model are in general agreement with results reported by other investigators. The performance of the model is illustrated by some examples, and a procedure for considering the case of a floating dead man is proposed.KEY WORDS: blast furnace; iron and slag levels; hearth drainage; tap rates.

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Section: Modeling the Iron Levelmentioning

confidence: 52%

Mathematical Modeling of Iron and Steel Making Processes. Modeling the Liquid Levels in the Blast Furnace Hearth.

Brännbacka

Saxén

2001

ISIJ International

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“…The assumptions about the outflow behavior of iron and slag are motivated by results from an earlier study of measurements of instantaneous slag and iron tap rates. 15) The moment at which slag starts to flow out was selected on the basis of results from both from physical and mathematical modeling reported in the literature, 13,14,[16][17][18] as well as findings from statistical tests on data from a large number of tap cycles. 15) Assumption d) is motivated especially in studies of the over-all behavior of the liquid levels during the tap cycle.…”

Section: Simplifying Assumptionsmentioning

confidence: 99%

Model Analysis of the Operation of the Blast Furnace Hearth with a Sitting and Floating Dead Man

Brännbacka

Saxén

2003

ISIJ International

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The phenomena in the blast furnace hearth are extremely complex and the possibilities to directly measure its internal state are practically non-existent. In order to control the process to achieve smooth operation and long campaigns, a thorough understanding of the conditions in the hearth is required. Such knowledge can be gained through mathematical modeling of the internal conditions. Since the properties of the dead man are known to considerably affect the hearth conditions, a model describing the operation of the hearth with a sitting, partially or completely floating dead man has been developed. Simulation of the tap cycle of a one-taphole blast furnace shows the effect of boundary conditions, hearth geometry, coke voidage and dead-man floating state on the evolution of the liquid levels and the slag delay. On the basis of the computed inner geometry of the hearth, the model has been applied to data from a six-year period of a Finnish blast furnace, and it has been found to accurately predict the long-term variations in the slag delay.KEY WORDS: blast furnace hearth; tap cycle; dead man floating; slag delay. scend further to a certain (given or calculated) level below the taphole at the end of each tap. Under these assumptions, the voidage of the dead man can be estimated once in every tap cycle from produced and tapped quantities of iron.According to Zulli, 13) a coke-free zone at the bottom of the hearth does not influence the cyclic behavior of the liquid levels as long as its volume is constant and it does not extend above the surface of the iron phase. However, if a coke-free zone below the dead man exists, the reason must be that the dead man is (at least partially) floating, so the position of the dead man, and thus also the size of the free space below it, depends on the volume of the liquids in the hearth. From this it follows that it is likely that the volume of the free space varies and affects the liquid levels. Therefore, the methods for estimating the dead-man voidage reviewed above apply only for a hearth with a sitting dead man. This is one of the motivations behind the modeling effort presented in the present paper, where the effect of a floating dead man on the liquid levels is investigated. In particular, the implications of dead-man floating on the slag delay, t sl , i.e., the time of iron-only flow in the beginning of the tap, is studied. Modeling The Tap CycleIn blast furnaces with one taphole, the tapping of iron and slag from the hearth follows a typical cycle, schematically illustrated in Fig. 1. When the taphole is closed both iron and slag accumulate in the hearth because of the progress of reduction and smelting of iron and slag formation. In the hearth the two liquids form separate layers, the dense iron on the bottom and the light slag layer floating on top of the iron bath. The taphole is generally kept plugged for at least 20-30 min to let the injected taphole mud solidify properly. Thus, as the tapping begins the iron-slag interface, henceforth called the iron level, is us...

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“…This study deals with the discontinuous flow of liquid in random packing, which could be used to understand realworld problems such as rainwater flow over windowpanes, water flow on plant leaves (in droplet form), volcanic eruptions (rivulets/droplets), and discontinuous liquid flow in many engineering disciplines [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] etc. as discussed in the introduction section.…”

Section: Liquid Flow In a Randomly Packed Bedmentioning

confidence: 99%

“…The liquid flow through a packed bed is quite common in many chemical engineering applications like distillation, 1,2) stripping, 3,4) catalysis, [5][6][7] and in metallurgical processes like blast furnace, [8][9][10][11][12] heap leaching. [13][14][15] Many researchers have modelled the liquid flow in packed beds using continuum hypothesis [16][17][18][19][20][21] for both wetting and non-wetting conditions.…”

Section: Introductionmentioning

confidence: 99%

Discrete Liquid Flow Behavior in a 2D Random Packed Bed

Gadi,

Gupta

2023

ISIJ Int.

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In many systems, the liquid flows in discrete rivulet/droplet form rather than continuous in non-wetting or low liquid flow rate conditions. A discrete liquid flow (DLF) theory has been used by a few researchers to describe these systems such as Ironmaking blast furnace. A few investigators have applied the discrete flow of liquid in structured packing where the particles are arranged in a particular pattern where void size and shape are fixed. However, in the real world, the packing system is random, for which the DLF theory has not been extended/verified. Also, DLF theory has not been verified for 2D structural packing in the absence of gas flow rigorously. In this article, this theory is not only validated for structural packing in the absence of gas flow but also extended and validated for 2D random packing. Random packing has been created using the Discrete Element Method. The void size and shape are determined using a novel graphbased algorithm in the random 2D bed to study the liquid flow. The liquid flow behaviour has been studied in various conditions, like changing the packing size and bed height. This study confirms that the bed topology plays an important role in dictating the liquid flow behavior in a randomly packed bed.

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A study on liquid flow in the blast furnace hearth

Cited by 4 publications

References 8 publications

Mathematical Modeling of Iron and Steel Making Processes. Modeling the Liquid Levels in the Blast Furnace Hearth.

Mathematical Modeling of Iron and Steel Making Processes. Modeling the Liquid Levels in the Blast Furnace Hearth.

Model Analysis of the Operation of the Blast Furnace Hearth with a Sitting and Floating Dead Man

Discrete Liquid Flow Behavior in a 2D Random Packed Bed

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