| 1. |
- Arzpeyma, Niloofar, et al.
(author)
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Development of a Mass and Energy Balance Model and Its Application for HBI Charged EAFs
- 2020
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In: Metals. - : MDPI. - 2075-4701. ; 10:3
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Journal article (peer-reviewed)abstract
- A static mass and energy balance model combined with a MgO saturation slag model is developed for electric arc furnaces. The model parameters including distribution ratios and dust factors are calibrated for a specific furnace using experimental data. Afterward, the model is applied to study the effect of charging different amounts of hot briquetted iron (HBI) on energy consumption, charged slag former amount, and slag composition. The following results were obtained per each 1% increase of HBI additions: (i) a 0.16 Nm(3)/t decrease in the amount of injected oxygen for metal oxidation, (ii) a 1.29 kWh/t increase in the electricity consumption, and (iii) a 34 kg increase in the amount of the slag.
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| 2. |
- Arzpeyma, Niloofar, et al.
(author)
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Model Development to Study Uncertainties in Electric Arc Furnace Plants to Improve Their Economic and Environmental Performance
- 2021
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In: Metals. - : MDPI. - 2075-4701. ; 11:6
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Journal article (peer-reviewed)abstract
- A statistical model is developed in order to simulate the melt composition in electric arc furnaces (EAFs) with respect to uncertainties in (1) scrap composition, (2) scrap weighing and (3) element distribution factors. The tramp element Cu and alloying element Cr are taken into account. The model enables simulations of a charge program as well as backwards estimations of the element concentrations and their variance in scrap. In the backwards calculation, the maximum likelihood method is solved by considering three cases corresponding to the involved uncertainties. It is shown that the model can estimate standard deviations for elements so that the real values lie within the estimated 95% confidence interval. Moreover, the results of the model application in each target product show that the estimated scrap composition results in a melt composition, which is in good agreement with the measured one. The model can be applied to increase our understanding of scrap chemical composition and lower the charged material cost and carbon footprint of the products.
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| 3. |
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| 4. |
- Compañero, Reinol Josef, et al.
(author)
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Appraising the value of compositional information and its implications to scrap-based production of steel
- 2023
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In: Mineral Economics. - : Springer Nature. - 2191-2203 .- 2191-2211.
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Journal article (peer-reviewed)abstract
- The current nature of steel design and production is a response to meet increasingly demanding applications but without much consideration of end-of-life scenarios. The scrap handling infrastructure, particularly the characterization and sorting, is unable to match the complexity of scrapped products. This is manifested in problems of intermixing and contamination in the scrap flows, especially for obsolete scrap. Also, the segmentation of scrap classes in standards with respect to chemical compositions is based on tolerance ranges. Thus, variation in scrap composition exists even within the same scrap type. This study applies the concept of expected value of perfect information (EPVI) to the context of steel recycling. More specifically, it sets out to examine the difference between having partial and full information on scrap composition by using a raw material optimization software. Three different scenarios with different constraints were used to appraise this difference in terms of production and excess costs. With access to perfect information, production costs decreased by 8–10%, and excess costs became negligible. Overall, comparing the respective results gave meaningful insights on the value of reestablishing the compositional information of scrap at the end of its use phase. Furthermore, the results provided relevant findings and contribute to the ongoing discussions on the seemingly disparate prioritization of economic and environmental incentives with respect to the recycling of steel.
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| 5. |
- Gyllenram, Rutger, et al.
(author)
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Blast furnace control after the year 2000
- 1996
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In: Steelmaking Conference Proceedings. - : Iron & Steel Soc of AIME, Warrendale, PA, United States. ; , s. 685-692
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Conference paper (peer-reviewed)abstract
- Rapid technical development together with developments in work organization makes it important to investigate possible ways to achieve a cost efficient process control of different metallurgical processes. This paper describes a research project, and proposes a human oriented Information Technology Strategy, ITS, for control of the Blast Furnace process. The method used is that of deductive reasoning from a description of the prevailing technological level and experiences from various development activities. The paper is based on experiences from the No. 2 Blast Furnace at Lulea Works but the conclusions do not at this stage necessarily reflect the opinion of the management and personnel or reflect their intentions for system development at SSAB.
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| 6. |
- Gyllenram, Rutger, et al.
(author)
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Driving investments in ore beneficiation and scrap upgrading to meet an increased demand from the direct reduction-EAF route
- 2021
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In: Mineral Economics. - : Springer Science and Business Media Deutschland GmbH. - 2191-2203 .- 2191-2211.
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Journal article (peer-reviewed)abstract
- The pressure on the steel industry to reduce its carbon footprint has led to discussions to replace coke as the main reductant for iron ore and turn to natural gas, bio-syngas or hydrogen. Such a major transition from the blast furnace-basic oxygen furnace route, to the direct reduction-electric arc furnace route, for steel production would drastically increase the demand for both suitable iron ore pellets and high-quality scrap. The value for an EAF plant to reduce the SiO2 content in DRI by 2 percentage points and the dirt content of scrap by 0.3 percentage points Si was estimated by using the optimization and calculation tool RAWMATMIX®. Three plant types were studied: (i) an integrated plant using internal scrap, (ii) a plant using equal amounts of scrap and DRI and (iii) a plant using a smaller fraction of DRI in relation to the scrap amount. Also, the slag volume for each plant type was studied. Finally, the cost for upgrading was estimated based on using mainly heuristic values. A conservative estimation of the benefit of decreasing the silica content in DRI from 4 to 2% is 20 USD/t DRI or 15 USD/t DR pellets and a conservative figure for the benefit of decreasing the dirt in scrap by 0.3 percentage points Si is 9 USD/t scrap. An estimate on the costs for the necessary ore beneficiation is 2.5 USD/t pellet concentrate and for a scrap upgrade, it is 1-2 USD/t scrap.
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| 7. |
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| 8. |
- Gyllenram, Rutger, et al.
(author)
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Lubricating the recycling machine
- 2012
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In: Revue de métallurgie (Imprimé). - : EDP Sciences. - 0035-1563 .- 1156-3141. ; 109:5, s. 349-358
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Journal article (peer-reviewed)abstract
- When introducing a new control paradigm in industry or society one has to accept that it is an evolutionary process where people, methods and processes must develop simultaneously, and this takes time. The recycling of material has been studied intensely for the last ten years using different approaches to material flow analyses, MFAs. They have given a good view of the magnitude of material flows but their use has been limited by lack of relevant data. In the case of recycling, data must be acquired from the practitioners of the trade and in order to get it, the value of the output for them and for society must be proved and visualized. This paper is based on a MFA model developed at KTH for steel flows in Sweden (part of the Swedish environmental research program, the "Steel-Eco-Cycle"). The aim of the work reported on here was to initiate the process of motivating better sampling of data in industry and society for performing MFAs. The KTH model is based on a product-to-product approach for steel, describing the recycling machine. Data is presented in a simplified model for Sweden with total figures and figures per capita. Areas where improvements can be made are identified and ways to "lubricate" the recycling machine are discussed. The main idea is to provide a way of describing flows that can be of use to recyclers and steel producers and form a basis for discussions on improvements. Finally, the underlying model is briefly described and the uncertainties of data are discussed.
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| 9. |
- Gyllenram, Rutger, et al.
(author)
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User friendliness : why are some beautiful models used while others are thrown in the wastepaper basket?
- 2008
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In: SCANMET III. - Luleå : MEFOS. - 9789163322693 ; , s. 315-322
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Conference paper (peer-reviewed)abstract
- Development and implementation of models in steel companies represent large values and will be even more important in the future. There are many pitfalls to step into in the process of modelling and implementation of systems. In this paper pitfalls and success factors experienced in six different projects are presented and discussed. Experiences like these are hard to earn and easily forgotten and it is concluded that this kind of knowledge management ought to be on the agenda for top management like the Corporate Technology Officer, CTO.
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| 10. |
- Nurdiawati, Anissa, et al.
(author)
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Towards fossil-free steel : Life cycle assessment of biosyngas-based direct reduced iron (DRI) production process
- 2023
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 393
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Journal article (peer-reviewed)abstract
- Given the urgent need for transitions towards global net zero emissions, decarbonisation of the iron and steel industry is critical. Deep decarbonising this sector requires a breakaway from current blast furnace-basic oxygen furnace (BF-BOF) technologies that largely depend on fossil resources. Biosyngas is considered to be a promising alternative to fossil energy and reductants used in existing ironmaking due to its renewability, technological maturity and compatibility for use in existing furnaces. The present work assesses the environmental impacts of biosyngas-based direct reduced iron production followed by electric arc furnace (DRI-EAF) routes for crude steel production. Further, the proposed routes are compared with the other steelmaking routes, including BF-BOF, natural gas (NG)-based and hydrogen-based direct reduction routes by performing life cycle assessment (LCA). The results indicate that the global warming potential (GWP) value for the biosyngas-based DRI-EAF system is 75% lower than the existing NG-based DRI-EAF route and 85% lower than the BF-BOF route. Moreover, the proposed system possibly has lower GWP values than the renewable hydrogen-based DRI-EAF route. The pro-posed system has an estimated cradle-to-gate GWP of 251 kg CO2 eq./t crude steel, of which 80% is from up-stream emissions. Combined with CO2 storage, the GWP of the proposed system is a net negative, estimated at-845 kg CO2 eq./t crude steel for the selected system boundary. In addition to GWP, other non-climate impact indicators are also evaluated to identify potential burden shifting. The results highlight the emissions reduction potential of the novel biosyngas DRI production route. Large-scale deployment, however, requires sustainable forest management and adequate CCS infrastructure, along with a strong, long-term policy framework to incentivise the transitions.
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