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Luleå, Sweden

Lindvall M.,Swerea MEFOS AB | Sichen D.,KTH Royal Institute of Technology
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2015

The solubility of vanadium oxide in the Al2O3-CaO(30 mass pct)-SiO2 system and Al2O3-CaO(35 mass pct)-SiO2 system was determined experimentally at 1873 K (1600 °C) and at a fixed oxygen potential of 9.37 × 10−11 bar. EPMA microanalyses were employed to identify the phases and their compositions in the quenched samples. The solubility of vanadium oxide in the liquid phase was found to decrease with increasing CaO content in the liquid. The vanadium oxide solubility was especially low when both CaO and Al2O3 contents were high in the liquid phase. The maximum solubility of vanadium oxide was up to 7 mass pct (as V). Two solid phases were found, a solid solution of Al2O3 and vanadium oxide and an Al2O3-rich solid phase with 16.7 mass pct V2O3. The Al2O3 solubility in the solid solution was found to increase with increasing Al2O3 content in the liquid, the impact of the CaO content in the liquid on the solubility of Al2O3 in V2O3 was found to be small. The Al2O3-rich solid phase was identified as the mineral hibonite with fractionation of V into the crystal structure. © 2014, The Minerals, Metals & Materials Society and ASM International. Source

When producing hot strip, HSLA(High Strength Low Alloyed) products the coiling temperature and the subsequent coil cooling is of great importance for the final mechanical properties. A thermo-mechanically coupled model has been developed where the anisotropic stress dependent thermal properties caused by the layered structure and the asymmetric cooling are included. Additionally the precipitation hardening effect on the yield strength, influenced by the thermal history during cooling was compared with mechanical tensile testing along the strip length at SSAB EMEA works in Borlänge, Sweden. Good agreement between measured and predicted yield stress variations in head and tail was obtained. © (2014) Trans Tech Publications, Switzerland. Source

Kajberg J.,Swerea MEFOS AB | Sundin K.-G.,Lulea University of Technology
Journal of Materials Processing Technology | Year: 2013

In order to characterise the mechanical response of materials in manufacturing processes, such as wire and bar rolling involving very high strain rates, temperatures and level of straining, an experimental device is presented. The device is suitable for testing at strain rates up to approximately 4000 s-1, temperatures up to 1200 °C (≈1500 K) and strains around 0.5. It is based on the classical Split Hopkinson pressure bar and is complemented with an inductive heating source for achieving requested temperatures. By keeping the specimen separated from the Hopkinson bars just until an instant before impact (50 ms) considerable cooling and temperature gradients in the specimen are avoided. Three steel grades, two stainless steels and a high-speed steel, were tested. Four different material models whose parameters were fitted to the obtained experimental data were used for mechanical characterisation: two empirically based and two physically based. Overall, one of the physically based models showed the best agreement between experimental results and the predicted flow stresses. © 2012 Elsevier B.V. All rights reserved. Source

Lundgren J.,Lulea University of Technology | Ekbom T.,Grontmij AB | Hulteberg C.,Nordlight AB | Hulteberg C.,Lund University | And 4 more authors.
Applied Energy | Year: 2013

Off-gases generated during steelmaking are to a large extent used as fuels in process units within the plant. The surplus gases are commonly supplied to a plant for combined heat and power production. The main objective of this study has been to techno-economically investigate the feasibility of an innovative way of producing methanol from these off-gases, thereby upgrading the economic value of the gases. Cases analyzed have included both off-gases only and mixes with synthesis gas, based on 300MWth of biomass. The SSAB steel plant in the town of Luleå, Sweden has been used as a basis. The studied biomass gasification technology is based on a fluidized-bed gasification technology, where the production capacity is determined from case to case coupled to the heat production required to satisfy the local district heating demand. Critical factors are the integration of the gases with availability to the synthesis unit, to balance the steam system of the biorefinery and to meet the district heat demand of Luleå. The annual production potential of methanol, the overall energy efficiency, the methanol production cost and the environmental effect have been assessed for each case. Depending on case, in the range of 102,000-287,000ton of methanol can be produced per year at production costs in the range of 0.80-1.1EUR per liter petrol equivalent at assumed conditions. The overall energy efficiency of the plant increases in all the cases, up to nearly 14%-units on an annual average, due to a more effective utilization of the off-gases. The main conclusion is that integrating methanol production in a steel plant can be made economically feasible and may result in environmental benefits as well as energy efficiency improvements. © 2013 Elsevier Ltd. Source

Grip C.-E.,Lulea University of Technology | Larsson M.,Swerea MEFOS AB | Harvey S.,Chalmers University of Technology | Nilsson L.,SSAB
Applied Thermal Engineering | Year: 2013

The energy network in Luleå consists of the steel plant, heat and power production and district heating. Global system studies are necessary to avoid sub-optimization and to deliver energy and/or material efficiency. SSAB began work with global simulation models in 1978. After that several more specialized process integration tools have been tested and used: Mathematical programming using an MILP method, exergy analysis and Pinch analysis. Experiences and examples of results with the different methods are given and discussed. Mathematical programming has been useful to study problems involving the total system with streams of different types of energy and material and reaction between them. Exergy is useful to describe energy problems involving different types of energy, e.g. systematic analysis of rest energies. Pinch analysis has been used especially on local systems with streams of heat energy and heat exchange between them. © 2012 Elsevier Ltd. Source

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