Holistic view of the insulating layer on the thermal efficiency of a steel ladle lining

Campos, Maria Gabriela Garcia; Santos, M.F.; Moreira, M.H.; Angélico, Ricardo Afonso; Sako, Eric Y.; Pandolfelli, V. C.

doi:10.1002/ces2.10043

Cited by 2 publications

(6 citation statements)

References 11 publications

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“…It was then possible to compare the temperatures of the refractory lining and determine the heat flux required to bring it back to thermal equilibrium. This could then be converted into a temperature loss from the steel to validate H3 that insulation reduces the cooling effect of refractories (2,3,(25)(26)(27). The method described was applied to the scenarios discussed in the following sections.…”

Section: Simulation Methodsmentioning

confidence: 99%

“…A model will only ever be accurate within an acceptable tolerance, a build-up of tolerances leads to an increase in temperatures produced. (19,(25)(26)(27)(28)(29)(30). By increasing the thermal conductivity it is possible to model the liquid steel via FEA because the heat transfer between liquid steel and refractory is higher than the simulated solid steel and refractory.…”

Section: Online Modelsmentioning

confidence: 99%

“…However, like CFD models the processing time is unable to keep up with the rate of production. FEA models are more commonly used due to the reduced simulation times and the reduced computer capacity requirements, with simulations taking several hours as opposed to days with CFD (19,(25)(26)(27)(28)(29). This gives companies a difficult choice between accuracy and costfrom an accuracy point of view the CFD models would be the best choice.…”

Section: Online Modelsmentioning

confidence: 99%

“…This can be done by measuring the insulation temperatures during production and recovering a sample of the insulation after it has been removed from the ladle. As discussed in the introduction to this chapter, the thermal efficiency of a teeming ladle is heavily influenced by the thermal conductivity of the insulation materials (2,3,(25)(26)(27). Gupta (2004) concluded that 55-60% of the heat lost from a full ladle is via heat transfer through the barrel when an insulation layer is not present (3).…”

Section: Ladle Insulationmentioning

confidence: 99%

“…Because this assessment was made in multiple studies it is interesting to note that there are minimal studies that investigate the post-mortem properties of microporous pyrogenic silica insulation (2,3,(25)(26)(27). By conducting a study on the post-mortem insulation it would be possible to determine how much the insulation degraded and the heat loss caused by the in-situ insulation properties.…”

Section: Ladle Insulationmentioning

confidence: 99%

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Thermal measurement and degradation quantification of teeming ladle refractories and the effects on the process

Cotton¹

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The key objective of the thesis was to quantify the heat loss caused to the liquid steel due to the cooling effect of the teeming ladle refractories. It was previously hypothesised that the in-situ degradation of insulation layer would increase this cooling effect. To determine the cooling effect of the degraded insulation material it was first thermally characterised with in-situ thermocouple measurements. Post-mortem samples were recovered from the teeming ladles used for the thermocouple measurements during their regular production cycles in a BOS plant. The post-mortem samples were then tested for their thermophysical properties. From this it was possible to determine the density increased from 260kg/m3 to 759.6 kg/m3, the thermal conductivity increased from 0.039W/m.K to 0.15W/m.K and the specific heat capacity decreased by 40% compared to its original state. These findings were then used to calculate the increased heat loss rate of the refractory material in the teeming ladle, which then in turn causes increased heat loss to the steel transported by the ladle. A thermal model was used to determine the heat flux stored in a fully saturated ladle and then different time periods of cooling with and without a lid. The effect of teeming ladle lids reduced the heat losses by up to 11°C per cycle compared to a ladle without a lid. Whereas the heat loss due to the insulative layer degradation was calculated to be <1°C for the initial heats before the ladle reached production temperatures and, therefore, had minimal effect. However, the degradation did show an increase in teeming ladle shell temperatures, which needs to be taken into account for service temperature monitoring. The thermal profiles of the modelled scenarios showed that if an accurate hot face measurement could be achieved it would be possible to accurately predict the cooling effect of each teeming ladle in production. This study was able to accurately measure the refractories and slag taken from a teeming and utilise the geometry of the ladle to reduce the error from thermal imaging. Previously predictions were used that could cause errors up to ±175°C when taking thermal images of the teeming ladle hot face. Through the method adopted in this study it was possible to take accurate measurements of the hot face within ±5°C. This can now be utilised by a thermal model to make accurate real time predictions of the heat loss caused by teeming ladle refractories. Thereby reducing the reheating required and improving the quality of steel produced.

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Section: Simulation Methodsmentioning

confidence: 99%

Section: Online Modelsmentioning

confidence: 99%

Section: Online Modelsmentioning

confidence: 99%

Section: Ladle Insulationmentioning

confidence: 99%

Section: Ladle Insulationmentioning

confidence: 99%

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Thermal measurement and degradation quantification of teeming ladle refractories and the effects on the process

Cotton¹

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Multi‐Response Optimization of the Thermal and Thermomechanical Behavior of a Steel Ladle Lining using Grey Relational Analysis and Technique for Order Preference by Similarity to Ideal Solution

Hou

Gruber

Jin

2022

steel research int.

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The present research attempts to simultaneously optimize the thermal and thermomechanical behavior of a steel ladle lining. The lining configurations are designed with an L32 orthogonal array considering the input parameters of various material properties and lining thicknesses. From the finite‐element (FE) simulations, three responses are evaluated: the end temperature and maximum tensile stress at the steel shell and the maximum compressive stress at the hot face of the working lining. Multi‐response optimization is performed through grey relational analysis (GRA) and the technique for order preference by similarity to ideal solution (TOPSIS) by applying a distinguishing coefficient of 0.5 in GRA and the signal‐to‐noise (S/N) ratio‐based weight in both techniques. Both GRA and TOPSIS results yield the same best solution (the fourth lining configuration) and the same optimal levels for significant factors. Analysis of variance (ANOVA) is used to identify the significance of the factors and their contributions to the overall performance characteristic. The results demonstrate that the top five factors with the analyses of GRA and TOPSIS are the same and their total contribution is similar.

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Holistic view of the insulating layer on the thermal efficiency of a steel ladle lining

Cited by 2 publications

References 11 publications

Thermal measurement and degradation quantification of teeming ladle refractories and the effects on the process

Thermal measurement and degradation quantification of teeming ladle refractories and the effects on the process

Multi‐Response Optimization of the Thermal and Thermomechanical Behavior of a Steel Ladle Lining using Grey Relational Analysis and Technique for Order Preference by Similarity to Ideal Solution

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