| 1. |
- Abhale, Prakash Bansi, et al.
(författare)
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Efficient computation of gas flow in blast furnace in 3-D
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012. - 9781627480215 ; , s. 722-732
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Konferensbidrag (refereegranskat)abstract
- Blast furnace continues to occupy prominent place among iron making technologies as it accounts for more than 90% of the hot metal produced in the world. In India, as a part of initiative from Ministry of Steel, efforts are being made to develop offline as well as online models with an aim to improve blast furnace performance. As a part of this effort, offline comprehensive models simulating the internal state of an operating blast furnace are being developed. Such comprehensive models involve systematic integration of various sub-models for gas flow, solid flow, reaction kinetics, enthalpy balance etc. Unlike in many other systems, these sub-processes are highly interlinked in blast furnace and hence call for large number of iteration among the sub-models which ultimately results in significant computation time. Our efforts in integration of these sub-models have indicated that the gas flow is one of the important bottle necks in achieving faster computation. This has led to a development of new and efficient computation scheme to simulate the gas flow in 2-D [1]. This new scheme provided efficient way of handling complex burden profile in a blast furnace. This paper presents the extension of this 2-D gas flow model to 3-D. Further, the 3-D model has been used to investigate the asymmetry in gas flow which can arise from blanking the tuyeres, asymmetric fusion or cohesive zone or formation scabs or scaffolds in the furnace behavior
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| 2. |
- Forsberg, Fredrik, et al.
(författare)
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3D sequential imaging and analysis of iron ore pellets under reduction by X-ray microtomography
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012. - 9781627480215 ; , s. 1744-1753
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Konferensbidrag (refereegranskat)abstract
- In this study, X-ray microtomography, combined with textural analysis, is used for 3D imaging of iron ore pellets and characterisation of interior cracks under a reduction process. The work is currently focused on the development of the methods and therefore the results mainly reflect the possibilities with the technique. Reduction experiments on a number of iron ore pellets were performed in 4 steps during the transformation from hematite to magnetite at 500°C. The pellet microstructure is imaged and visualized before reduction and after each subsequent reduction step using x-ray microtomography and the crack distribution characterized with image analysis. For the chosen pellet composition, networks of cracks are already visible in the unreduced state and show a successive growth during the first half of the reduction process. However, this growth stops during the second half of the process, and for the majority of the investigated samples a certain regression of the crack size is observed. Although further studies are needed, it can be concluded that the use of X-ray microtomography has the potential to become an important tool for material characterization in iron ore pellet research due to its ability to gather information from the bulk of the material at several different stages of a process.
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| 3. |
- Hyllander, Gunilla, et al.
(författare)
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Innovative measurement technique for raceway monitoring
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012 - Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore. - 9781627480215 ; , s. 1732-1743
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Konferensbidrag (refereegranskat)abstract
- When raceway conditions are changed, e.g blast parameters or selection of injection material, additional measurements and monitoring of raceway can support evaluation of the effects on raceway conditions. Two types of measurement methods have been tested during injection trials with BF flue dust at the SSAB EMEA BF in Oxelösund and the LKAB Experimental Blast Furnace (EBF®). The raceway depth was measured using microwave technique and a camera was installed for viewing the raceway when the peep hole was occupied by the depth measurements equipment. Temperature estimation was made on thermal radiation guided via an optical fibre from the raceway to a spectrometer. Evaluation methods were developed based on Planck radiation law. The measurement techniques and their use for monitoring of raceway conditions are discussed.
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| 4. |
- Motta, Ricardo S. N., et al.
(författare)
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Pneumatic conveyor dynamic models for a pulverized coal plant
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012. - 9781627480215 ; , s. 91-103
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Konferensbidrag (refereegranskat)abstract
- This article describes new advanced non-linear dynamic models for pulverized coal injection (PCI) plant into blast furnaces. A complete new approach for modelling is developed for the actual state-of-art PCI injection station. These models take into account all the physical dynamic laws and pneumatic conveyor variables allied to a modern updated digital control system (DCS). The models were constructed to operate in real time for the same DCS that controls the industrial PCI plant. Process validations include pressure and modern mass flow meter specially designed to check the models. New verification variables allowed by these equipments shows the functionality of the dynamic model-based, thermal, pressure profile and the particle velocity models. The models can be used mainly to improve coal flow stability control by means of modern control strategies and to prevent clogging lance caused by low coal particle speed and high solid to gas ratio.
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| 5. |
- Semberg, Pär, et al.
(författare)
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Magnesium diffusion in magnetite-olivine diffusion couple during oxidation and reduction: Preliminary laboratory study
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012 - Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore. - 9781627480215 ; , s. 1268-1277
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Konferensbidrag (refereegranskat)abstract
- The solid-state diffusion of magnesium through iron oxides is important in understanding the oxidation and reduction of iron ore pellets containing olivine. In this study, a diffusion couple was made of olivine (containing 50% MgO) and magnetite. Initially, experiments were conducted under oxidizing atmosphere at a temperature above 1,250°C. A new 100-micron thick layer of magnesioferrite and 11% Mg now appeared at the interface of the couple. In the oxidized iron oxide layer there was no detectable presence of Mg. Subsequently, the oxidized samples were subject to reduction atmosphere sufficient for formation of wustite. The layers of oxidized magnetite (i.e. hematite) and the magnesioferrite reduced to wustite. In the reduced samples, the magnesium level in the wustite by the interface was found to be 1.5 wt%. At distance of 700-1,000 μm from the olivine boundary, the magnesium levels went below detection limit. A diffusion coefficient was estimated from the data. The implication of these observations in iron ore pellets will be discussed.
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| 6. |
- Tikka, Janne, et al.
(författare)
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Utilization of tornado processed blast furnace gas cleaning sludge in blast furnace injection
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012 - Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore. - 9781627480215 ; , s. 1957-1966
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Konferensbidrag (refereegranskat)abstract
- Significant quantities of waste materials or by-products are generated every day from the global steel industry. These materials contain substantial amounts of valuable compounds for example carbon or iron. Utilization of wet gas cleaning sludge from the blast furnace process is limited to as an additive in sinter production due to its fine particle size, high moisture and undesirable elements content. Test campaigns with a novel material handling process called Tornado have been carried out in order to enable utilization of recycled BF gas cleaning sludge in BF injection. Gas cleaning sludge containing over 40% of moisture was dried to less than 3% of residual moisture. The product from the Tornado-process: Powder with high Fe and C-contents was characterized for its physical injection and chemical properties. Injection trials were successfully carried out in the LKAB Experimental Blast Furnace to further validate material suitability to blast furnace injection as a reducing agent replacing PCI and coke as well as an iron bearing material replacing sinter and pellets. This paper describes the conducted work and analyzes the results.
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| 7. |
- Ökvist, Lena Sundqvist ., et al.
(författare)
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Injection of pulverized materials into the blast furnace raceway
- 2012
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Ingår i: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012 - Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore. - 9781627480215 ; , s. 1721-1731
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Konferensbidrag (refereegranskat)abstract
- A number of injection trials carried out over the years at the LKAB experimental blast furnace (LKAB EBF®) and in industrial BFs shows that tuyere injection is a feasible method for supply of various types of pulverized materials as different types of PC, BOF slag and BF dust to the BF. In this study, the effect on process, raceway conditions, hot metal quality, reductant agent consumption and slag formation due to the selection of injection materials are discussed based on trial data. A special attention is paid on the injection of alternative carbon containing residual material. Based on recent trials the efficiency in use of carbon in injected residual materials are discussed and pilot scale results compared with industrial trial results.
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