Model of the State of the Blast Furnace Hearth.

Torrkulla, J.; Saxén, Henrik

doi:10.2355/isijinternational.40.438

Cited by 69 publications

(77 citation statements)

References 2 publications

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“…The process variables required for the simulation of the two states are given in Table 2. The hearth geometry estimated by the wear model, 5) discussed further in the next subsection, was simplified to cylindrical shape by taking averages of the hearth depths and diameters, yielding the values reported in columns four and five of Table 2. The geometrical simplifications were introduced to make the examples more transparent and easier to interpret.…”

Section: Resultsmentioning

confidence: 99%

“…5,21) Considerable variations in the slag delay were observed in BF B, showing a strong negative correlation with changes in the volume of the hearth. In BF A no correlation between slag delay and hearth volume has been observed, even though the hearth volume has varied considerably.…”

Section: Simulationmentioning

confidence: 98%

“…5) Since changes in hearth-coke voidage or other parameters of the model were unable to explain the radical fluctuations in the slag delay, the effect of dead-man floating was studied with the model. In order to make it possible to simulate partial floating of the dead man, the radial distribution of the pressure of the burden was modeled by a simple parametric expression.…”

Section: Discussionmentioning

confidence: 99%

“…2.4 does not require a symmetric (or cylindrical) geometry. Since the wear model 5) monitoring the hearth geometry produces a number of two-dimensional profiles of the hearth at different angles relative to the taphole, the corresponding sectors, as illustrated in Fig. 9, can be used in Eqs.…”

Section: Setupmentioning

confidence: 99%

“…Models for such estimation on the basis of thermocouple measurements in the lining have been presented in literature and have been found to fairly well describe the hearth geometry on a long-term basis. [1][2][3][4][5] The properties of the dead man are extremely difficult to estimate. On the tuyere level core drilling can be used to sample dead-man coke, [6][7][8][9] but the technique can only be used at stoppages, it is fairly expensive, and it is laborious to analyze the samples.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

Section: Simulationmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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Inverse geometry heat transfer problem based on a radial basis functions geometry representation

Gonzalez¹,

Goldschmit²

2006

Int. J. Numer. Meth. Engng

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SUMMARYWe present a methodology for solving a non-linear inverse geometry heat transfer problem where the observations are temperature measurements at points inside the object and the unknown is the geometry of the volume where the problem is defined. The representation of the geometry is based on radial basis functions (RBFs) and the non-linear inverse problem is solved using the iteratively regularized Gauss-Newton method. In our work, we consider not only the problem with no geometry restrictions but also the bound-constrained problem.The methodology is used for the industrial application of estimating the location of the 1150 • C isotherm in a blast furnace hearth, based on measurements of the thermocouples located inside it. We validate the solution of the algorithm against simulated measurements with different levels of noise and study its behaviour on different regularization matrices. Finally, we analyse the error behaviour of the solution.

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Data‐driven Analysis of Sulfur Flows and Behaviour in the Blast Furnace

Helle

Saxén

2008

steel research international

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Sulfur has for long been known as a problematic element for the quality of iron, but along with its accumulation it also causes physical problems in the blast furnace, so it is of central importance to safeguard its removal from the process. Sulfur‐related problems in the blast furnace were studied by applying a balance equation for the element at three industrial blast furnaces, tracking errors in the in‐ and outflows and estimating changes in the amount of accumulated sulfur. A hypothesis on the behaviour of sulfur in the process was proposed and supporting evidence of it was found through an analysis of dynamic phenomena in the hearth of one of the furnaces.

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Model of the State of the Blast Furnace Hearth.

Cited by 69 publications

References 2 publications

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

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

Inverse geometry heat transfer problem based on a radial basis functions geometry representation

Data‐driven Analysis of Sulfur Flows and Behaviour in the Blast Furnace

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