On‐line model of gas distribution in the blast furnace

Nikus, Mats; Saxén, Henrik

doi:10.1002/srin.199605468

Cited by 7 publications

(6 citation statements)

References 2 publications

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“…In a model for estimation of the burden distribution on the basis of gas temperature measurements, [3] efforts are made to exploit the first factor, while the local gas flow rates are suggested to be estimated using independent techniques. [10] Since the measured temperature does not change abruptly after charging because of sensor dynamics, a temperature change computed over a longer period of time must be utilized. This is why it is important to understand the general dynamic behavior of the temperatures in the upper shaft.…”

Section: Discussionmentioning

confidence: 99%

Simplified simulation of the transient behavior of temperatures in the upper shaft of the blast furnace

Saxén

1998

Metall Mater Trans B

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A one-dimensional dynamic model of the upper part of the blast furnace shaft is applied to study the evolution of gas and burden temperatures, mainly in order to shed light on the transient phenomena after charging dumps of burden. The effects of irregularities in the burden descent and charging are also studied briefly. The simulations demonstrate that the temperatures of the burden layers in the lower part of the simulated region assume a quasi-steady state, indicating that the changes in the top gas temperature experienced immediately after a dump of burden arise primarily because of heat transfer between the gas and the dump. These results support the idea that such temporary changes can be interpreted in terms of distribution of the dumps on the burden surface.

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Section: Discussionmentioning

confidence: 99%

Simplified simulation of the transient behavior of temperatures in the upper shaft of the blast furnace

Saxén

1998

Metall Mater Trans B

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Section: Pressure Drop and Burden Descent Ratementioning

confidence: 99%

“…3.2 of Ref. 1)), which affects not only gas distribution 18) and permeability but also burden descent; 7) it is a well-established fact that an over-filling of the hearth slows down the driving rate.The gas pressure drop and the burden descent rate are, however, affected by a large number of other process variables and disturbances, such as changes in blast volume and …”

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confidence: 99%

Indicators of the Internal State of the Blast Furnace Hearth.

et al. 2002

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The hearth is a crucial region of the blast furnace, since the life of its refractory may be decisive for the campaign length of the furnace. Excessive growth of skull on the hearth wall and bottom, in turn, reduces the inner volume of the hearth, causes drainage and other problems that limit productivity, and has a negative effect on hot metal temperature and chemistry. A set of indicators that reflect the internal state of the hearth has been developed. The motivation for the indicators is outlined and their application to hearth state detection is illustrated with several examples from the operation of two Finnish blast furnaces.KEY WORDS: blast furnace hearth; dead man state; erosion and skulling; slag delay. Indicators of the Hearth State Lining Wear and SkullingA model estimating the residual lining and the thickness of the skull layer on the hearth wall and bottom has been developed.7) The routine determines the location of the 1 150°C-isotherm that gives the best match between measured and calculated temperatures for a set of two-dimensional vertical cross-sections of the hearth (Fig. 1), aggregating the results into a three-dimensional representation of the internal profile, as shown in Fig. 2. The model describes the state of the lining and its results can be used as a basis for decisions on control and maintenance actions, e.g., whether a relining or injection of Ti-bearing materials to form protective skull on the hearth lining should be scheduled to avoid a breakout, or if a drop in hot metal production is necessary to avoid excessive hot metal velocities. By examining the evolution of the 3-D representation, it is possible to follow the progress of the erosion and skulling in time. However, when the results of the model are correlated with other process data, it may be more useful to study the evolution of quantities such as the available hearth volume, 6) calculated on the basis of the model's results (cf. Sec. 3). The Internal State of the Hearth CokeIn spite of its name, the dead man, i.e., the core of the hearth coke, is known to play an important role for the operation of the blast furnace. Its shape and permeability influence the hot metal and slag velocities and flow patterns in the hearth, and, therefore, also affect the erosion or formation of skull and the drainage of the two liquid phases. Heat and mass transfer between the slag and iron phases are also affected by the dead man state. Furthermore, the dead man may also have an impact on the conditions in the upper part of the furnace through its possible vertical motion along with changes in the levels of liquids in the hearth. In the following, some indicators of the state of the hearth coke are presented. Slag Delay and Hearth Coke VoidageA simple but extremely informative variable that reflects the internal state of the hearth is the slag delay, t slag , i.e., the time that elapses after the tap is started until slag enters the runner. The delay, which is roughly a function of the (extreme) levels of the iron-slag interface and the ta...

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“…mathematical models of gas and burden distribution (Saxen 1996;Nikus and Saxen 1996), should be used in the conjunction with the classifier. Therefore, additional information, extracted by, e.g.…”

Section: Operation Diagramsmentioning

confidence: 99%

Industrial Applications of Soft Computing

Leiviskä¹

2001

Studies in Fuzziness and Soft Computing

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On‐line model of gas distribution in the blast furnace

Cited by 7 publications

References 2 publications

Simplified simulation of the transient behavior of temperatures in the upper shaft of the blast furnace

Simplified simulation of the transient behavior of temperatures in the upper shaft of the blast furnace

Indicators of the Internal State of the Blast Furnace Hearth.

Industrial Applications of Soft Computing

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