| 1. |
- Cuervo-Piñera, Victor, et al.
(författare)
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Blast Furnace Gas Based Combustion Systems in Steel Reheating Furnaces
- 2017
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; , s. 357-364
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Konferensbidrag (refereegranskat)abstract
- The usage of steelmaking process gases in thermoprocessing plants is the most efficient way to reduce the natural gas dependence and therefore both fuel costs and carbon footprint in steelworks. Furthermore NOx emissions can be cut by firing lean gases considering their low adiabatic flame temperatures. A European funded project aiming to enhance the usage of blast furnace gas (BFG) in steel reheating furnaces has been successfully accomplished by a multidisciplinary international consortium of research centers (ArcelorMittal Global R&D Asturias and Maizières, Centro Sviluppo Materiali, Swerea MEFOS, VDEh-Betriebsforschungsinstitut), burner suppliers (Tenova, AGA Linde) and end-users (ArcelorMittal). Three innovative preheated fuel gas burner technologies, namely double regenerative air-fuel, oxy-fuel and flat-flame burners, have been designed and manufactured for 100% BFG firing, so that the inherent constraints of burning very lean gases have been overcome. On the one hand, flameless oxy-fuel combustion with central preheated BFG, so that capital expenditures are limited, allowing easily furnaces retrofitting and potentially carbon capture. On the other hand, for air burners a dual honeycomb regenerator that preheats both air and BFG streams at the burner level, so that operating costs are reduced. Finally, an oxy-regenerative flat-flame burner that transfers homogeneously radiant heat to the load, combining the two beforehand mentioned technologies that are used mainly for high capacity burners (higher than 0.5-1 MW). These systems have been tested (long-term) at both pilot plant and industrial scale in order to define the guidelines for a safe application in the industrial environment, to address technical and economic issues and to put forward guidelines for retrofitting existing furnaces. Moreover, computational fluid dynamics (CFD) modelling has been carried out and validated with the pilot testing results, so that a numerical set-up has been defined for BFG firing. For this purpose a new radiation model for the radiative properties of the products of combustion of BFG has been developed, considering the low water vapor-carbon dioxide ratio. By means of preheating BFG with the waste heat content in flue gases stream, the typical operating temperatures of reheating furnaces (1350°C) have been achieved without natural gas enrichment, keeping the NOx emissions level below the European regulation threshold. © 2017 The Authors. Published by Elsevier Ltd.
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| 2. |
- Niska, John, et al.
(författare)
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Combustion Control Using An IR Diode Laser
- 2003
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Tunable diode laser absorption spectroscopy (TDLAS) is a recent development in process instrumentation. A commercial TDLAS instrument has been tested both in an industrial steel reheating furnace and in a pilot furnace at MEFOS for continuous oxygen analysis of the furnace combustion gases. Automatic control of the air-to-fuel ratio (AFR) was proven using a time-averaged oxygen concentration signal with a TDC2000 furnace controller at MEFOS. The oxygen concentrations measured by the TDLAS instrument compared well with local measurements of the oxygen concentration using a conventional zirconia probe in both furnaces. The diode laser has the advantages of high reliability for average gas concentration measurements in the path of the beam, when compared to point gas analysis with conventional zirconia instrumentation. Reliable gas analysis offers the benefits of improved process control, which for steel reheating furnaces include energy savings, reduced emissions and improved productivity.
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| 3. |
- Saffari Pour, Mohsen, 1987-, et al.
(författare)
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The behavior of impurities during producer gas implementation as alternative fuel in steel reheating furnaces : A CFD and thermochemical study
- 2016
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Ingår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). - USA : American Society of Mechanical Engineers (ASME). - 9780791850589
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Konferensbidrag (refereegranskat)abstract
- The use of available and cheap industrial producer gases as alternative fuels for the steel reheating furnaces is an attractive topic for steel industry. The application of producer gases for such furnaces introduces not only the complicated combustion system of Low Calorific Value (LCV) gases, but also several impurities that could be problematic for the quality of final steel products. The quality of steel can be highly affected by the interaction of impurities with iron-oxides at hot slab surfaces. In this research, the combustion of producer gases and the behavior of impurities at the steel slab surface are studied by aid of a novel coupled computational fluid dynamics (CFD) and thermodynamics approach. The impurities are introduced as mineral ash particles with the particle size distributions of 15-100 νm. The CFD predicted data regarding the accumulation of ash particles are extracted from an interface layer at the flaring gas media around the steel slab surface. Later on, these predicted data are used for the thermo-chemical calculations regarding the formation of sticky solutions and stable phases at the steel slab surface. The results show that the particles are more likely follow the flow due to the high injection velocity of fuel (70 m/s) and the dominant inertial forces. More than 90 percent of particles have been evacuated through the exhaust pipes. The only 10 percent of remaining particles due to the high recirculation zones at the middle of furnace and the impinging effect of front walls tend to stick to the side wall of slab in the heating zone more than the soaking zone.
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| 4. |
- Sjögren, B., et al.
(författare)
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Test of electromagnetic, non-destructive method for determining material properties in steel
- 2014
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Ingår i: La Metallurgia Italiana. - : Associazione Italiana di Metallurgia. - 0026-0843. ; 106:10, s. 23-27
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Tidskriftsartikel (refereegranskat)abstract
- This study, in the area of non-destructive testing and measuring technology, shows that it is possible to inspect and determine the mechanical properties and micro structure of a material using electro-magnetic technique. The goal has been to on-line determine material properties like residual stress distributions, variations in tensile strength and fatigue strength in a material. In the project the latest in materials inspection using electro-magnetic methods combined with statistic modelling is used. The project has shown that these new methods can non-destructively determine the mechanical properties of a material or a machine detail. It is believed that this measuring technique has a clear place in industry.
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