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

2020 ◽  
Vol 2 (3) ◽  
pp. 113-129
Author(s):  
Maria Gabriela Garcia Campos ◽  
Matheus Felipe Dos Santos ◽  
Murilo Henrique Moreira ◽  
Ricardo Afonso Angélico ◽  
Eric Yoshimitsu Sako ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Ladle Lining ◽  
Steel Ladle ◽  
Holistic View ◽  
Insulating Layer

Computational Heat Transfer Analysis of the Effect of Skirts on the Performance of Third-World Cookstoves

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
Alex Wohlgemuth ◽  
Sandip Mazumder ◽  
Dale Andreatta
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Third World ◽  
Heat Transfer Analysis ◽  
Vertical Position ◽  
Dynamics Model ◽  
Unknown Parameters ◽  
Insulating Layer ◽  
Computational Predictions

In many developing countries, natural gas, wood, or biomass fired cookstoves find prolific usage. Skirts, placed around the cookpot, have been proposed as a means to improve the thermal efficiency. However, use of skirts has shown conflicting results, and the role of skirts is poorly understood. In this study, a computational heat transfer analysis of a generic third-world cookstove is conducted with the goal to understand the effect of various skirt-related parameters on the overall heat transfer characteristics and thermal efficiency. A computational fluid dynamics model, including turbulence and heat transfer by all three modes, was created. The model was first validated against the experimental data, also collected as part of this study. Unknown parameters in the model were calibrated to better match the experimental observations. Subsequently, the model was explored to study the effects of several skirt-related parameters. These include the vertical position of the skirt, the width of the gap between the skirt and the cookpot, and the thermal conductivity of the skirt (insulating versus conducting material). The computational predictions suggest that the skirt must either be made out of an insulating material or insulated on the outer surface by a backing insulating layer for it to provide maximum benefits. It was also found that it must be placed at an optimum distance away from the cookpot and aligned with the mouth of the cookstove chimney for maximum thermal efficiency. An optimum set of conditions obtained through this computational analysis resulted in an increase in the thermal efficiency from 20.7% to 28.7%.

Key features of alumina/magnesia/graphite refractories for steel ladle lining

2000 ◽  
Vol 20 (9) ◽  
pp. 1419-1427 ◽  
Author(s):  
W.S Resende ◽  
R.M Stoll ◽  
S.M Justus ◽  
R.M Andrade ◽  
E Longo ◽  
...  
Keyword(s):  
Ladle Lining ◽  
Steel Ladle ◽  
Key Features

scholarly journals Drying behavior of steel-ladle lining refractory castables under continuous heating rate

2021 ◽  
Author(s):  
T.M. Cunha ◽  
M.H. Moreira ◽  
M.F. Santos ◽  
A.P. Luz ◽  
V.C. Pandolfelli
Keyword(s):  
Heating Rate ◽  
Ladle Lining ◽  
Continuous Heating ◽  
Steel Ladle ◽  
Refractory Castables ◽  
Drying Behavior

scholarly journals A Method for Steel Ladle Lining Optimization Applying Thermomechanical Modeling and Taguchi Approaches

JOM ◽  
2018 ◽  
Vol 70 (11) ◽  
pp. 2449-2456 ◽  
Author(s):  
Aidong Hou ◽  
Shengli Jin ◽  
Harald Harmuth ◽  
Dietmar Gruber
Keyword(s):  
Ladle Lining ◽  
Steel Ladle ◽  
Thermomechanical Modeling

scholarly journals Corrosion Mechanism of A Density-Reduced Steel Ladle Lining Containing Porous Spinel-Calcium Aluminate Aggregates

Ceramics ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 155-170 ◽  
Author(s):  
Christoph Wöhrmeyer ◽  
Jianying Gao ◽  
Christopher Parr ◽  
Magali Szepizdyn ◽  
Rose-Marie Mineau ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Service Life ◽  
Calcium Aluminate ◽  
Porous Matrix ◽  
Thermomechanical Properties ◽  
Ladle Lining ◽  
Magnesium Aluminate ◽  
Steel Ladle ◽  
Corrosion Mechanism ◽  
Calcium Magnesium

Refractory monolithics for steel ladle linings are typically products with low porosities and high bulk densities. They achieve high temperature, penetration, and corrosion resistance. Despite the high density of these products, which is due to the low porosity of the aggregates, their matrices still exhibit a high amount of pores. Since calcium magnesium aluminate (CMA) has already proven its resistance to penetration and corrosion as a binder in the matrix, this paper investigated if alumina spinel refractories containing microporous calcium magnesium aluminate aggregates can withstand conditions that occur in a steel ladle wall. The objective was to reduce the castable density with the advantage of a lower material requirement for a ladle lining and reduced heat and energy losses. This was achieved by replacing dense alumina aggregates by up to 38% of porous CMA aggregates (grains with 30 vol% porosity), which resulted in a bulk density reduction from 3.1 g/cm3 for the dense alumina castable to 2.8 g/cm3 for the 38% CMA aggregates containing castable. However, the despite the higher porosity, penetration, and corrosion resistance and thermomechanical properties were not impacted negatively for a model alumina spinel castable. A postmortem investigation was conducted on a newly developed dry-gunning mix that was installed in a steel ladle wall on top of a slag penetrated castable and that achieved a service life of 31 heats versus only 18 heats for the reference mix that contained dense alumina and spinel aggregates. This new repair mix contained the newly designed porous CMA aggregates, which in this case partly replaced the dense alumina and spinel aggregates. These porous aggregates consisted of magnesium aluminate and calcium aluminate micro-crystals. The postmortem study revealed two important phenomena that can explain the improved performance: at the hot face in contact with steel and slag, a thin densified zone was observed that blocked the slag penetration into the porous matrix and the porous aggregates. Iron oxides were almost completely blocked from penetration, and only some manganese oxide was observed in the penetrated zone together with some silica and lime from the slag. Clusters of calcium aluminate (CA6) and magnesium aluminate (MA) spinel build the refractory back-bone on the hot side of the material and gussets filled with mostly glassy calcium aluminum silicates close to the hot face and gehlenite further inside the penetrated zone. Alumina grains had a reaction rim consisting of CA2 or CA6 and a very intimate connection to the surrounding matrix unlike the CMA-free mix that showed micro cracks around the alumina grains. At the colder side, the gunning mix with CMA aggregates showed a very good connection to the substrate, supported by a hercynite formation in the gunning mix resulting from a cross-reaction with remains of iron oxide on the CMA containing repair mix. Furthermore, macroscopic observations of a CMA aggregate containing alumina magnesia castable in the metal zone of a steel ladle revealed that macro cracks developed only very slowly, which resulted in a superior service life.

scholarly journals Influence of Variation/Response Space Complexity and Variable Completeness on BP-ANN Model Establishment: Case Study of Steel Ladle Lining

2019 ◽  
Vol 9 (14) ◽  
pp. 2835
Author(s):  
Aidong Hou ◽  
Shengli Jin ◽  
Dietmar Gruber ◽  
Harald Harmuth
Keyword(s):  
Material Behavior ◽  
Space Complexity ◽  
Ladle Lining ◽  
Steel Ladle ◽  
Ann Model ◽  
Predictive Tool ◽  
Node Number ◽  
Hidden Layer ◽  
The Impact

Artificial neural network (ANN) is widely applied as a predictive tool to solve complex problems. The performance of an ANN model is significantly affected by the applied architectural parameters such as the node number in a hidden layer, which is largely determined by the complexity of cases, the quality of the dataset, and the sufficiency of variables. In the present study, the impact of variation/response space complexity and variable completeness on backpropagation (BP) ANN model establishment was investigated, with a steel ladle lining from secondary steel metallurgy as the case study. The variation dataset for analysis comprised 160 lining configurations of ten variables. Thermal and thermomechanical responses were obtained via finite element (FE) modeling with elastic material behavior. Guidelines were proposed to define node numbers in the hidden layer for each response as a function of the node number in the input layer weighted with the percent value of the significant variables contributing above 90% to the response, as well as the node number in the output layer. The minimum numbers of input variables required to achieve acceptable prediction performance were three, five, and six for the maximum compressive stress, the end temperature, and the maximum tensile stress.

scholarly journals An alternative lining of steel ladles: technical and economic aspects

2018 ◽  
pp. 72-80
Author(s):  
L. M. Akselrod ◽  
V. Garten
Keyword(s):  
Phenol Formaldehyde ◽  
High Heat ◽  
Ladle Treatment ◽  
Ladle Lining ◽  
Concrete Lining ◽  
Steel Ladle ◽  
Refractory Materials ◽  
Metal Quality ◽  
Gaseous Hydrocarbon ◽  
Steel Making

Quality of steel ladles lining to a big extent determine the economic efficiency of steel-making operation. Direct costs on the refractory lining of them can reach 30–50 % of the costs of lining of a steel-making complex. Experience of utilization of refractory materials of different composition considered with the purpose of efficiency increase of refractory materials application in the steel ladles lining under conditions of steel ladle treatment. Considerable abilities shown to make the lining of steel ladle walls and bottom by both carbon-containing and carbon-free refractory materials taking into account the economic aspect. Lining base of steel-making facilities — BOFs, EAFs and steel ladles — is composed by periclase-carbon (MgO–C) refractories. However those refractories have a high heat conductivity, that effects on the heat operation of steel ladles. When using MgO–С materials, vertical fractures can appear in the ladle walls lining as its residual thickness becomes small. Under definite conditions a working lining chipping takes place, problems appear with lining destruction in the pieces angles with cavities formation at the pieces joining. To level the MgO–С drawbacks, periclase-alumo-carbon (MgO–Al2O3–С) and alumo-periclase-carbon (Al2O3–MgO–С) refractory products are used. Al2O3–MgO–C refractories are widely used in most erosion-intensive lining zone — in the combatting place of steel ladle bottom lining. In Russia monolithic lining of steel ladle bottom is successfully displacing the lining by piece products, including alumo-periclase-carbon ones. Such a replace enables to decrease specific refractory consumption and specific costs of them. At present the technology of concrete application to bottom is implemented for ladles of BOF- and steel-making shops. A technology of concrete ladle walls and bottom is intensively implemented for 120–180-ton ladles. The concrete lining of steel ladles has the following advantages: high withstandability against impregnation by metal-slag melt; absence of metal carbonization by the carbon from ladle lining; increase of running duration of safety lining layer by 2–2.5 times; absence of necessity to use nest blocks in both steel outlet unit and for bottom blow-off lance; absence of cracks in lining, wash-outs in seams, angles and edges of pieces; decrease of gaseous hydrocarbon emissions(phenol, formaldehyde, benzapilene) during lining drying, heating-up and operation (only slag belt remains, where pieces have organic binders); saving of materials, working time and manpower while making and maintain the lining; decrease of specific consumption and specific costs for lining per 1t of steel. For lining of steel ladles of big volumes (more 250 t) alumo-periclase (alumo-spinel) products are widely used in China, Europe and Japan. For such a lining the thermo-mechanical tension, arising in monolithic ladle lining, has a less importance, including at its replacing with metal by using crane. It is easier for the products to compensate the ladle geometry change, resulted in metal shall geometry change in time. A positive influence of carbon-free lining, as well as a lining with low content of magnesium oxide, on metal quality noted, first of all for low- and ultralow carbon grades, and pipe low-alloyed steels.

Suppression of decarbonization and resource characteristics of carbonated spinel-corundum refractories in steel-ladle lining

2021 ◽  
pp. 104-112
Author(s):  
S. A. Suvorov ◽  
A. P. Shevchik ◽  
V. V. Kozlov ◽  
N. V. Arbuzova
Keyword(s):  
Mass Transfer ◽  
Pore Structure ◽  
Experimental Studies ◽  
Ladle Lining ◽  
Steel Ladle ◽  
Functional Zones ◽  
Slag Melt ◽  
Technical Properties ◽  
Resource Characteristics ◽  
Hot Surface

Experimental studies of changes in the pore structure and physical and technical properties of carbonated spinel-corundum refractories under different conditions of decarbonization and the formation of a protective regulatory layer on their hot surface, suppressing decarbonization of the refractory material and mass transfer between the lining and the flow of slag melt, are presented. The results of industrial tests of carbonated spinel-corundum refractories in the working layer of the lining of a 400-ton steel-ladle lining, as well as the topography and consumption specific coefficients of refractories for the functional zones of the ladle lining, the amount of refractory destruction products of the lining during its operation are considered.

scholarly journals Corrosion resistance of alumina-magnesia castable to slag in steel ladle lining

2011 ◽  
Vol 119 (1396) ◽  
pp. 916-921 ◽  
Author(s):  
Yoshitaka SADATOMI ◽  
Naoya ENOMOTO ◽  
Junichi HOJO
Keyword(s):  
Corrosion Resistance ◽  
Ladle Lining ◽  
Steel Ladle
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