Maarten Geerdes, Geerdes Advies, Netherlands

Abstract:
Summary. Biocrude oil for ironmaking Frans Goudriaan and Jaap Naber, BioFuel B.V., Rendorppark 30, 1963AM, Heemskerk, The Netherlands, info@biofuel.com Maarten Geerdes, Geerdes Advies, Mient 3B, 1901AB Castricum, The Netherlands, geerdes@mgeerdes.nl Paper submitted to ECIC & ICSTI 2022 Joint Conference, Bremen, 29. August - 2. September 2022 The Hydrothermal Upgrading Process (HTU®) is capable of producing biocrude from biomass and consolidates ~70% of the energy content. Biomass residues from sugarcane, palm oil, forestry or cultivation of energy crops can be used. The process is technically feasible as shown in a pilot plant producing from 500 kg dry biomass 200 kg biocrude/day. The next step is construction of a demonstration plant, that will process 25.000 ton biomass to 10.000 ton biocrude per year. The biocrude produced from the Hydrothermal Upgrading Process (HTU®) is separated by extraction to a minerals-free light crude (LCR) and heavy crude (HCR). Application of biofuels for ironmaking will be discussed. • Injection of LCR into blast furnaces, which is similar to heavy fuel oil injection used extensively for ironmaking until the mid-1970’s. LCR injection can replace most if not all coal injection in blast furnaces. • From HCR coke can be produced. The product is similar to pet-coke with a very low S-content. Pet coke percentage in the coal blend for coke making can reach 25-30% of the coal blend. • The biocrude and/or LCR can be used in direct reduction plants (DRI). The crudes can be injected with or without gasification by some additional oxygen. The injected crude will be converted to syngas in the DR reactor replacing natural gas and/or hydrogen. In total an estimated 50% of carbon used for ironmaking in blast furnaces can be replaced by a sustainable source. The HTU® process can produce LCR at a cost of 7 €/GJ, or 245 €/ton.

Bart de Graaff, Danieli Corus, Netherlands

Co-Author:
Jan De Weerdt, Danieli Corus
Michael Skorianz, Danieli Corus

Abstract:
In the light of European climate actions the steel industry is faced by the challenge to reduce its substantial carbon footprint. This works focusses on the evaluation of low and medium scale investments to reduce the CO2 emissions for the production of liquid hot metal. A comprehensive and easy to use methodology for estimating the (change in) carbon emissions is provided and several real life case studies are described to serve as example.

Nicholas Aubry, Hatch, Canada

Co-Author:
Tom Honeyands, University of Newcastle / Newcastle Institute for Energy and Resources
Ben Ellis, BHP
Xinliang Liu, BHP
Kyle Lefebvre, Hatch Ltd.
Ian Cameron, Hatch Ltd

Abstract:
As part of the European Community’s Ultra-Low Carbon Dioxide Steelmaking (ULCOS) program, blast furnace top gas recycling was tested to reduce CO2 emissions using the LKAB experimental blast furnace. During tests from 2007-2010, the blast carbon rate was reduced by about 25% when CO recovered from blast furnace top gas was re-injected into the furnace stack using a second bustle pipe. Hatch and BHP have re-visited the top gas cycling concept to assess if additional technologies such as hydrogen and hot oxygen injection could be implemented to further reduce CO2 emissions beyond what was achieved at the experimental blast furnace. Using a 2-stage heat and mass balance model, viable operating conditions were established for a low carbon rate operation, significantly less than what was achieved in the ULCOS trials. Details of the enabling technologies to reach such low CO2 emission rates will be presented.

Michael Cremer, thyssenkrupp Steel Europe AG, Germany

Abstract:
Coke plant Schwelgern, commissioned in March 2003, is still running the biggest coke ovens worldwide with a coke output of more than 56 tons per oven. The so-called Coke Stabilizing Quenching, the state of the art regarding wet quenching processes, realizes the procedure of coke quenching. The two quenching towers are the highest industrial wood constructions worldwide and hardly stressed by the coke quenching process itself. The presentation illustrates the quenching process itself and shows the different steps of maintenance optimization in a battlefield of abrasion. The presentation gives also an impression about the actual project of demolishing and new erection of Quenching Tower No. 2.

Volodymyr Kuskov, Paul Wurth S.A., Luxembourg

Co-Author:
Christian Dengler, Paul Wurth S.A.

Abstract:
As the equipment designer, Paul Wurth has an intimate knowledge of the WHY’S of the equipment design as well as an in-depth knowledge of process and equipment logic and operations of the latest technology. Growing global competition and increasing pressure to maximise production efficiency are key forces acting on the adoption of new digital tools within the iron and steel industry. Organisations recognise the importance of extracting and analysing information from data, as well as persisting and amplifying knowledge accumulated during years of experience in the types of equipment used in the primary iron making industry. The following will focus data acquisition and on knowledge-based condition monitoring systems and their practical application in maintenance, specifically for the Paul Wurth coke oven machines and in particular for our Stamping Charging Pushing Machines. Monitoring and evaluating the condition of complex equipment requires analysis of everything from simple variable data to recognition of trends and complex phenomena resulting from multiple factors. Effective evaluation of critical events in the operation of complex equipment may rely on knowledge acquired from both human and machine. A secure platform and tools that allow integration of human and machine learning can enable continuous growth of baseline knowledge used to operate and monitor critical assets. Digitally captured knowledge from process and equipment experts with an abundance of real-time data adds the potential to predict and prevent asset failure by identifying and preventing the re-occurrence of detected failures and recognize repetitive events. Enabling engineers with tools omitting the need for programming or data science experience makes this possible. Rule engines driven by human knowledge reduce the potential for overwhelming operators faced with continuous alerts requiring no immediate remedy or action. THE COMPLETE ABSTRACT IS ATTACHED.

Bert Gols, Tata Steel Europe, Netherlands

Abstract:
The integrated steel site in IJmuiden has two coke plants to supply coke to the blast furnaces. Major rebuilds are not economically feasible. So the challenge is to keep these coke plants in operation for as long as possible to remain at least self-sufficient. Especially Coke Plant # 2 is vulnerable for high coking pressures due to its age (45+ years), weaker design and higher oven walls. To control coking pressure, pilot test facilities are used to measure the gas pressure. A good relation between gas pressure and pushing force of a coke oven was found. Limiting the amount of power required to push an oven is believed to prevent damage to an oven wall. In the pilot oven the gas pressure of all blending piles entering the coke plant is measured as well as all individual coal shipments and several trial blends to investigate intended blend changes. The dataset of all the pilot oven tests is used to develop predictive models for gas pressure. This model requires the data of the individual coal test to widen the data range to give the model predictive power outside the range of blends used for the coke plant. Even though a model like this can predict the general direction and variation between coal types quite well, it fails to predict the difference between various shipments of the same coal. A further investigation into this revealed that variations in moisture and particle size of the same coal type have influenced the gas pressure measurement. These variations do not show up in analytic models, because the influence of these factors is coal type dependent. When the limitations and constraints of these models are understood they can be a useful tool in the optimisation of the coal blends and protection of our assets.

Michael Specht, Refratechnik Steel GmbH, Germany

Co-Author:
Michael Cremer, thyssenkrupp Steeleurope

Abstract:
The requirements for the door plug building blocks of the Schwelgern coking plant are particularly challenging due to the door height of 8.43 meters. In order to ensure the tightness of the doors, the durability of the insulating bricks of the coke oven doors, the so-called door plug components, is essential for a safe oven door repair process. In the course of the continuous improvement of processes (CIP), the proven door plugs modules of the Schwelgern coking plant were further improved. The focus of further improvement was on reducing the expansion coefficient of the components in order to achieve a longer service life and less susceptibility to cracking. Initial tests in the laboratory and in practice showed positive results and confirmed the theoretical approach. In addition to the newly developed material grade, the prefabricated components were reinforced with a special steel fiber to achieve another positive effect. The operational experience of the last six years, which is shown in this presentation, shows that the newly developed components outperform the conventional parts in terms of service life. The consumption of door plug modules could be reduced significantly.

Reinoud van Laar, Danieli Corus BV, Netherlands

Co-Author:
Co Author, Hyundai Steel Company
Reinoud Van Laar, Danieli Corus

Abstract:
Dust emissions are occurring at the blow-down and shut-down of a Blast Furnace if the bleeder valves are used. Modern societies and their governments are therefore imposing more stringent legislation and permitting, which may necessitate interim plant modifications. A new clean gas vent line has been developed and demonstrated at Hyundai Steel Company to eliminate any dust emissions at blow-down and shut-down procedures as the gas will be cleaned by the wet scrubber before its release to ambient air. A comprehensive health and safety analysis has been executed to ensure that any operations and maintenance risks would be eliminated. The system design has been optimized to prevent any changes to the original standard operating procedures for blow-down and shut-down. The project contract to commissioning has been realized within four months and the clean gas vent line has since then been successfully used at multiple occasions.

Arndt Wilhelmi, Lechler GmbH, Germany

Co-Author:
Eduardo Bernauer, Lechler GmbH
Willi Jansen, Lechler GmbH

Abstract:
When cleaning off gases e.g. from blast furnaces, many different factors have an influence on the performance of venturi scrubbers or other wet cleaning systems e.g. coke quenching towers. Even small components, such as nozzles and separators, can have a big influence on the overall performance of these systems. The correct nozzle selection is essential, with the knowledge of pressure, volumes, process conditions, positions and the resulting precise droplet spectrum. This influences important factors such as exhaust gas saturation, reduction of dust deposals, dust wetting, pre-separation and the overall performance, etc. In addition, after the scrubber, the separation of the droplets, with the dust particles inside, is very important. For example, spin vane separators have a very poor efficiency with a high-pressure drop. In modern applications, special adapted and designed lamella separators are installed in order to achieve very low emission levels with low-pressure drops. The investment and maintenance cost are normally lower compared to other installations.

Jan Altgaßen, Beck u. Kaltheuner Feuerfeste Erzeugnisse GmbH & Co. KG, Germany

Co-Author:
Ansgar Schepers, Beck u. Kaltheuner Feuerfeste Erzeugnisse GmbH & Co. KG

Abstract:
In recent years, nanoscaled materials have gathered significant importance in the production of refractory castables and gunning/shotcreting products. The reason for this trend lies in the reduction of the refractory microstructure down to the nanometre range and an associated significant improvement in the physical and mechanical parameters. The main objectives for nanomaterial applications are to improve compressive strength, tensile strength, elasticity, resistance to thermal shock, abrasion, chemical corrosion and a favourable ratio of strength to Young’s modulus. Moreover, along with better performance nanoscaled binders make shorter turnaround times and thus reduce energy consumptions feasible. In this paper, we report on the progress made in the development of colloidal silica-based sol-gel refractories for the blast furnace hearth, the main and tilting runner. These nanobonded refractories can be applied via casting, dry gunning and shotcreting. Sol-gel refractories are often associated with low green strength after demoulding and preshapes are susceptible to cracking at the shop floor stage. Technological approaches to work with precast and shotcreted sol-gel bonded refractories will be presented. Furthermore, different developments to overcome some of the challenges that occur while handling sol-gel bonded refractories are presented.

Afshin Sadri, Hatch, Canada

Co-Author:
Wai Lai (Winnie) Ying, Hatch

Abstract:
For the most part, blast furnaces' campaign life relies on the condition of their hearth refractory lining. The hearth refractory lining mainly consists of carbon, micropores, graphite, and ceramic caps or some combination of two or three of these mentioned brick types. Blast furnace lining undergoes severe thermal-mechanical and thermal-chemical abuses that result in its wear and deterioration. Aside from direct hot metal wear, penetration and percolation of gasses within the lining, particularly the walls, affect the lining by causing chemical instability and failure of its material properties. In other words, the integrity of the blast furnace refractory systems is critical to its continuous operation. Hence, a comprehensive, multisource, risk-based, and dynamic management program is required to ensure that no sudden failures interrupt the operation. The hearth being the critical section of the furnace, its refractory thickness and quality must always be known. This information requires reliable and steady data sources acquired during furnace operation. The primary data is provided by various non-destructive testing (NDT) inspection and monitoring techniques, which do not interrupt furnace operation. The secondary data is provided by furnace operation and controls, such as the coke, pellet/sinter, flux quality and chemistry, all the output gases, chemistry, and temperatures. An integrated risk-based refractory management system is designed to reduce the probability of lining failure and increase the furnace campaign life.

Reinoud van Laar, Danieli Corus BV, Netherlands

Abstract:
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Fabio Muscolino, Paul Wurth Italia, Italy

Co-Author:
Zak van der Westhuizen, METIX
Joe Bartholme, Paul Wurth S.A.
Stefano Magnani, Paul Wurth Italia
Fabio Cravino, Paul Wurth Italia

Abstract:
Smart combination of new Midrex direct reduction plants in existing blast-furnace-based integrated plants: solutions for lowering OPEX and CO2 emissions vs the stand-alone approach

Richard Elliott, Hatch Ltd., Canada

Co-Author:
Ian Cameron, Hatch Ltd.
Laura Mariani, Hatch Ltd.
Sa Ge, Hatch Ltd.

Abstract:
Hydrogen-based ironmaking is widely accepted as a critical enabling technology for the decarbonization of the steel industry. As adoption of this technology progresses, low-carbon and carbon-free DRI will become increasingly available for use in electric steelmaking. Traditionally, EAF operators have valued the carbon present in DRI for the operational benefits it brings. While decarbonizing the ironmaking process promises significant environmental benefits, these must be reconciled with the practical requirements for carbon in steel and consider the most effective route to deliver carbon into the steelmaking process. Process models of typical iron and steelmaking technologies are used to consider the environmental, technical, and economic advantages and limitations involved in the use of low-carbon and carbon-free DRI in EAF steelmaking. In doing so, guidance will be provided on the practical implications of a future where hydrogen-based ironmaking is commonplace.

Kyle Chomyn, Hatch Ltd, Canada

Co-Author:
Terrence Koehler, Hatch Ltd
Sa Ge, Hatch Ltd

Abstract:
The future of steelmaking requires changes to achieve significant reduction of green house gas emissions, using new process flowsheets. One approach commonly considered is the use of direct reduced iron (DRI) with an electrical arc furnace (EAF); however, this poses significant challenges when using lower grade ores / pellets and when using hydrogen-DRI. This paper describes a method to improve the process yield and efficiency, using an electric melting furnace. The melting furnace efficiently converts DRI into pig iron, for downstream use in an EAF or basic oxygen furnace (BOF). The melting furnace leverages advanced furnace technology developed over 60+ years for iron / ferro-nickel applications. This new approach eases the shift to green steelmaking by using existing facilities and pellet supply chains, and provides higher yields and reduced lifecycle costs.

Axel Sormann, K1-MET GmbH, Austria

Co-Author:
Michael Zarl, K1-MET GmbH
Axel Sormann, K1-MET GmbH
Bernhard Geier, voestalpine Stahl Donawitz GmbH
Christoph Thaler, voestalpine Stahl Linz GmbH
Johannes Schenk, Montanuniversitaet Leoben

Abstract:
Climate change, mainly caused by gaseous emissions like CO2, is globally one of the most important subjects. Significant efforts are required to solve this problem within the following decades. The European Commission´s low carbon roadmap suggests a reduction of CO2 emissions of 80 % by 2050 compared to 1990 levels. The steel industry, which contributes around 6 % to the worldwide anthropogenic emissions of CO2, is asked to decrease the greenhouse gas emissions. There are two possible pathways to perform low-C economy: Carbon Direct Avoidance (CDA) and Smart Carbon Usage (SCU). In the case of SCU, process integration with reduced carbon input and carbon capture and usage are being performed. CDA includes hydrogen- and electricity-based metallurgy to remove carbon as a reducing agent for iron ore. In this paper, CDA using hydrogen as a reducing agent for iron ore will be presented. Since 1980, laboratory investigations at the Montanuniversitaet Leoben/Austria have been shown that hydrogen – especially in the plasma state – is an excellent reducing agent for iron oxides. Based on the results of these investigations and previous laboratory work, a consortium of scientific and industrial partners decided to go a step ahead and build a bench-scale plant for HPRS (Hydrogen Plasma Smelting Reduction). The upscaling from the laboratory to bench-scale ranges from 100 g to 100 kg of iron ore. In this bench scale plant, which is located at the Donawitz site of voestalpine, smelting reduction tests using hydrogen in gas mixtures are being carried out. A transferred plasma arc will reduce and meltdown fine-grained iron ore in one step while the ore is fed into the plasma arc through a hollow electrode. One of the challenges is to generate a stable process for the plasma arc. For this purpose, investigations are carried out regarding the influence of the electrode material

Ko-ichiro Ohno, Kyushu University, Japan

Co-Author:
Kazuya Kunitomo, Kyushu University
Takayuki Maeda, Kyushu University
Shungo Natsui, Tohoku University
Shingo Ishihara, Tohoku University
Takashi Watanabe, Tokyo Institute of Technology
Hirokazu Konishi, Osaka University

Abstract:
Correct knowledge about softening behaviour of iron burden in cohesive layer is becoming more and more important for the minimum carbon blast furnace operation. In order to precisely understand cohesive behaviour, a unique softening simulator under rapid heating and quenching conditions was applied. Outcomes from normal softening simulator are very complex because they depend on reduction degree, chemical composition, basicity, melts physical property, etc. One of the reasons to make complex this test is sample for this test provided as particle packed bed. In order to comprehend softening behaviour of cohesive zone, focus on behaviour of single particle as a component of particle packed bed in this study. For simplification, a pre-reduced simulant sinter iron ore was prepared as single particle sample. The samples were made from mixture of reagent oxides and they were pre-reduced to several reduction levels. The sample was rapidly heated up to 900℃, and then gradually heated up with 10℃/min under inert gas atmosphere and 0.1MPa load. Shrinkage degree of the sample particle was measured during the softening test, and quenched sample was made at certain temperature when the sample shows a characteristic tendency. Cross-sectioning observation of the quenched sample provided mineral phases distribution in the sample particle. The observation indicated that peripheral structure has a significant effect on deformation resistance. Especially in there, existence of molten slag phase could make easy to deform the sample particle shape, and metallic solid Fe phase helped to strengthen the particle's deformation resistance.

James Small, Tata Steel, Netherlands

Co-Author:
Chloe Buytendijk, Tata Steel
Stefan Melzer, Tata Steel
Sieger van der Laan, Tata Steel
Kooij Chris, Tata Steel
Enno Zinngrebe, Tata Steel
Yanping Xiao, Tata Steel
Magdalini Ntouma, Tata Steel
Frank van der Does, Tata Steel
Mary Wijngaarden-Kroft, Tata Steel

Abstract:
Here we discuss the influence of chemistry, mineralogy and microstructure of iron ore sinter on its reduction behavior under conditions relevant to the upper shaft and the reserve zone of the blast furnace process. Sinter material was produced in a sintering pot varying only limestone flux- and coke addition rate with an otherwise constant sinter mixture, to yield variation in basicity (CaO/SiO2: 1.7 – 4.1) and FeO (6 - 19 wt%). This material was coarsely ground and screened to 250-500 µm and used as starting material for isothermal reduction treatments in lab-experimental gas-mixing furnaces at the following conditions: (1) 750 °C with XCO (= CO/[CO+CO2]) of 0.55; and 950 °C with XCO of (2, 3 & 4 respectively) 0.65, 0.76, 0.90. The experimental starting materials thus retain the mineralogical and microstructural variations of quasi-industrial sinter, while excluding mesostructural variations (e.g. sinter size). Long duration experiments were performed to compare the resultant net reduction degree and mineralogy with (Factsage-)predicted thermodynamic equilibrium. Excellent agreement was found between the predicted and measured reduction degree of samples from long-duration experiments within the wustite stability field (conditions (1) & (2)), with broad agreement too in terms of mineralogical composition. Samples were consistently less reduced than predicted with conditions (3) & (4), reflecting kinetic limitations. For (4), these are the formation of dense metallic layers around wustite domains in the case of lower-basicity sinters, and the sluggish reduction of metastably formed brownmillerite (C2(A,F)) to metallic Fe, lime and Ca-aluminate in higher basicity sinters. Shorter duration time-series experiments performed at conditions (1) and (2) show clearly the passage of sequential concentric reaction(-zone) fronts through the particles. Categorical differences are seen in the initial reduction behavior of Si-Al-rich SFCA versus Fe-rich SFCA-I, while all SFCA types remain initially unreacted as the hematite-magnetite reaction front passes.

Olli Mattila, SSAB Europe Oy, Finland

Co-Author:
Timo Paananen, SSAB Europe Oy
Lauri Halonen, Sapotech Oy
Juha Roininen, Sapotech Oy
Iikka Salmela, Sapotech Oy
Henrik Saxen, Åbo Akademi

Abstract:
Ironmaking pellets transported overseas are usually moist to prevent dust emissions during vessel loading. Dust generation cannot be avoided when pellets collide on conveyor system parts and when they move in contact with each other starting from the pellet incineration line and ending in the blast furnace (BF). Due to restrictions in available field area or construction costs, large pellet storage silos are not optimized with respect to fines flow behavior. Their operation often leads to the accumulation of fines and the discharge of sudden pulses of fines. Pellet fines pulses together with moisture create sieving problems prior to the BF and in the BF process itself by impairing burden permeability and, in consequence, BF stability. If the share of fines in the feed is constant, it is possible to fine-tune the sieving practice and charging pattern in the BF to maintain a proper permeability distribution. To tackle the uneven fines discharge-related problem, the behavior of fines in silos during sequential charge and discharge cycles was modeled with the Discrete Element Method (DEM). Based on the modeling results, a new systematic practice to fill and discharge the storage silos was applied in the automation system. To measure the amount of fines in the pellet stream discharged from large storage silos, an optical image analysis measurement on the bottom of the conveyor line was developed. In addition, the separated fines originating from multiple simultaneously operating sieving machines were analyzed with respect to pellet quality with a newly installed conveyor balance and simple delay model. By combining information from the extracted flow of fines with measurements of pellet moisture, the fines flow to the BF is estimated, and the information can be used for taking appropriate actions to guarantee BF operation stability.

Igor Shepetovsky, JSC "Kosaya Gora Iron Works" , Russian Federation

Co-Author:
Ivan Chmerenko, Kosaya Gora Iron Works
Andrew Shalygin, Kosaya Gora Iron Works
Rustam Nuriev, Kosaya Gora Iron Works
Konstantin Myasnikov, Kosaya Gora Iron Works
Alla Shepetovskaya, Kosaya Gora Iron Works

Abstract:
Stringent requirements of contemporary production of high-duty castings and special grades of steel lead to a new approach specific to basic burden material for foundry and special steelmaking which tends to use of virgin ferrous material with minimum impurities. Over a long period Kosaya Gora Iron Works (Tula, Russia) develops blast furnace technology for large scale manufacturing of pig iron with extended set of quality requirements in accordance with the above mentioned new approach. Along with the typical task to minimize content of conventionally detrimental sulfur and phosphorus in pig iron, technologists of Kosaya Gora must minimize content of manganese, titanium, vanadium and other tramp elements (up to 10 elements in all) in produced pig iron. Partially this task is solved due to application of ferrous burden with 100% pellets which are chemically purer than sinter. This paper describes peculiarities of production of high quality pig iron with precise qualitative properties through blast furnace route using state-of-the-art technologies and equipment.

Xue Feng Dong, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Australia

Co-Author:
Apsara Jayasekara, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong
Dominique Sert, ArcelorMittal Maizieres Research SA
Rodolfo Paulo Santos Ferreira, ArcelorMittal Maizieres Research SA
Pascal Gardin, ArcelorMittal Maizieres Research SA
Brian Monaghan, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong
Sheng Chew, Coke & Ironmaking Technology, BlueScope Ltd
David Pinson, Coke & Ironmaking Technology, BlueScope Ltd
Paul Zulli, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong

Abstract:
Molten slag, which is primarily generated in the blast furnace (BF) cohesive zone, trickles down through the coke packed bed in the form of films, rivulets or droplets in the lower zone of the BF. During its downward flow, there are significant interactions occurring between slag and other phases. In terms of these interactions, slag flow behaviour can greatly affect BF productivity and be associated with furnace irregularities. Hence, understanding the interactions between phases is useful to maximizing BF efficiency. In the current study, a Volume of Fluid (VOF) modelling technique was applied to track the movement of individual slag droplets at a mesoscopic level. The numerical modelling was firstly developed and validated through comparisons between simulation and experimental results via qualitative and quantitative methods. The VOF approach was then used to investigate the slag flow behaviour in the packed bed, considering various bed permeabilities, more wide-ranging slag properties, and strong interactions between slag and other phases. Results demonstrate the significant role of modelling at a mesoscopic level in understanding macroscopic slag flow behaviour. Modelling work helps to visualize the trickling behaviour of slag droplets in more realistic and complex conditions representing a BF, and clarify the mechanisms of the different flow patterns generated for variations in operating conditions. As examples, flow characteristics such as localised slag flooding and gas channelling caused by the strong interaction between gas and slag were uniquely identified and analysed. As the hydrostatic pressure dominates the flow of rivulets downwards, slag and liquid iron enhance their respective flows through the bed rather than retard each other. The current modelling proved to be a valuable tool to provide a foundation for better understanding the slag flow behaviour and its interactions with other phases in the BF lower zone.

Fabian Perret, RWTH Aachen University, Germany

Co-Author:
Alexander Babich, RWTH Aachen / IEHK
Dieter Senk , RWTH Aachen / IEHK

Abstract:
The raceway parameters such as the temperature (RAFT and real temperature), the temperature distribution, and the ignition/combustion characteristics of injected auxiliary reducing agents (ARA) have a strong impact on the operational parameters of the blast furnace process. Due to the fact that various factors influence the raceway conditions, it is necessary to monitor these conditions under changing blast parameters, e.g. hot wind volume, hot wind temperature, oxygen content and the injection rate of auxiliary reducing agents (ARA). Using various BF operational conditions, it is crucial to gain a deeper understanding of the adjustments necessary to achieve a high PC and a low coke rate. This contribution focuses on the applicability of thermovision camera (TVC) measurements for the analysis of raceway conditions, and in particular for an investigation of the interplay between the blast furnace parameters and the raceway conditions, in order to optimise the BF process. To analyse the influence of these process parameters, two TVC measurement campaigns were conducted at two different European blast furnaces during coal injection. The TVC measurements were used to investigate the temperature distribution of the injected coals (PC) in the raceway and their influence on the blast furnace. The statistical software programme Stata was used for data analysis. The results will be used to improve and support raceway and shaft models, as well as predictions of the effect of PC residues (such as char) and their behaviour on the BF operation. Unburnt coal or PC conversion degree affects both measured temperature and RAFT.

Thomas Nanz, K1-MET GmbH, Austria

Co-Author:
Michael Harasek, TU Wien ICEBE
Magdalena Schatzl, K1-MET GmbH
Johannes Rieger, K1-MET GmbH
Hugo Stocker, voestalpine Stahl Donawitz GmbH
Christoph Feilmayr, voestalpine Stahl GmbH
Franz Hauzenberger, Primetals Technologies Austria GmbH
Markus Bösenhofer, K1-MET GmbH / TU Wien ICEBE

Abstract:
Injection of auxiliary reducing agents (ARAs) is a common approach to replace metallurgical coke in the blast furnace iron making process. A variety of ARAs is currently used, e.g. natural gas, coke oven gas, pulverized coal, heavy and waste oil, biomass, and carbonaceous dust. Conversion rates of ARAs are hardly available in literature, which makes the optimization of the ARA injection process and the evaluation of new ARAs troublesome. Identifying new ARAs requires suitable experimental setups and accurate methods for the extraction of the conversion rates. Experiments should reproduce the conversion conditions of the raceway zone of blast furnaces. Significant temperature and species concentration stratification might occur in such experimental equipment. A combined methodology using CFD simulations and experimental data can be used to obtain accurate conversion rates. Spatially resolved temperature, velocity, and species concentration profiles can be obtained via CFD simulations. In addition, accurate residence times can be extracted from these simulations via Lagrangian particle tracking. In case of strong stratification effects, the simulated profiles are superior to the typically assumed constant temperature, velocity, and species concentrations. Usually residence times are estimated by assuming plug flow. These residence times deviate from the experimental ones, since flow phenomena, e.g. vortexes or radial velocity profile, are neglected when assuming plug flow. Using realistic temperature and species concentration profiles as well as residence times refines the accuracy of the extracted conversion rates and kinetic parameters. In this work, we first introduce a CFD approach for the simulation of experimental equipment and the methods to determine the transient temperature and species concentration profiles. Subsequently, we introduce and discuss a computer aided kinetic extraction algorithm and compare their results with kinetic parameters determined by traditional approaches.

Yakov Gordon, Hatch, Canada

Co-Author:
Andrei Sorokin, NLMK
Vladislav Listopadov, NLMK
Vladimir Titov, NLMK
Larisa Gileva, Ural Federal University
Sergei Myasoedov, NLMK
Sergei Filatov, NLMK
Segei Zagainov, Ural Deferal University

Abstract:
Based on the result of theoretical analysis, it has been shown that injection of pulverized coal supports process conditions either to provide higher smelting rate or achieve minimum coke specific consumption. In case of coke and natural gas replacement, two conflicting factors can be observed: gas amount per minute is reduced thus having a favorable effect on gas dynamics both at upper and lower zones of the furnace; porosity is decreased in slag formation zone. It determines extreme correlation between PCI (pulverized coal injection) consumption and blast furnace performance. It has been established that increasing ratio of PCI to natural gas (NG) consumption is followed by lower coke and total carbon in fuel specific consumption at slowdown. High smelting rate can be achieved with this ratio within the range of 2.0-2.5.

Martina Hanel, Mettop GmbH, Austria

Co-Author:
Hans-Jörg Krassnig, Mettop GmbH
Andreas Filzwieser, Mettop GmbH
Martina Hanel, Mettop GmbH

Abstract:
ILTEC is a new patented cooling technology, developed by Mettop GmbH in Austria, to overcome the disadvantages of water by using an alternative cooling medium, namely the ionic liquid IL-B2001. Since the use of water - today’s standard cooling medium - has major drawbacks as it can cause fatal explosions in case of leakages or malfunction. In contrast to that, IL-B2001 is non-flammable, non-corrosive, non-toxic and minimizes explosions due its low vapor pressure. Not only in highly stressed areas, as our reference at the blast furnace tap hole of ArcelorMittal Bremen shows, an alternative cooling medium minimizes the risks of fatal accidents. Also new ways of furnace cooling can be achieved in order to increase the lifetime of lances, side wall areas and even furnace bottom areas. The paper will highlight potential as well as already implemented applications for the iron and steel industry for making iron and steelmaking a more safe industry.

Martina Hanel, Mettop GmbH, Austria

Co-Author:
Javier Bolado, Welding Copper
Andreas Filzwieser, Mettop GmbH
Hans-Jörg Krassnig, Mettop GmbH

Abstract:
Mettop and WeCo have developed an innovative casting process enabling the only real copper-in-copper pipe cast by cooling with ionic liquid. The result is excellent metallurgical bond between copper tube and copper casting which leads to both long life time and recyclability of the copper cooler. Mettop and WeCo joined forces to develop this new safe production method for copper coolers aiming for improved thermal and mechanical properties and consequently extended lifetime not only limited to tuyeres. In order to get the best performance and the longest lifetime of these tuyeres it is best to use copper tubing for the cooling circuits. This entails the challenge of putting a thin metal structure into a surrounding with a large amount of liquid metal with a higher temperature then the melting point of the tube. Therefore a method we developed which allows sufficient refrigeration of a copper cooling circuit during the casting process in order to prevent the melting or deformation of the tube. As the cooling with gases is not sufficient and the use of water is extremely dangerous in presence of liquid metals - the only viable option keeping work safety in mind, is to cool with an Ionic Liquid. These liquids can be tailored in their characteristics in order to fit the application. In this case it is a cooling medium which can be used up to 250 °C and which is safe in handling and in case of direct contact to liquid metal. Mettop holds the patent to the only non-corrosive and non-toxic Ionic Liquid specifically designed for metallurgical applications – the IL-B2001. Therefore a co-operation between WeCo and Mettop has been formed in order to overcome the challenges of producing large cooling elements which are entirely made from copper in a safe way.

Edward Long, Primetals Technologies, United Kingdom

Co-Author:
Ross Edmond, Primetals Technologies
Jarmo Naula, SSAB Europe Oy

Abstract:
In a blast furnace, copper staves are often used to protect the shell in the highest heat zones. These staves are in turn protected from the abrasive burden material by freezing semi-molten material onto the stave face, forming a skull and preventing wear. The stability of this skull is therefore essential to achieving a long stave life which consequently allows a longer and more stable blast furnace campaign. Primetals Technologies have developed a solution which traps burden material at the front of the stave whilst still allowing liquids through to the copper face – the result is a more stable skull and improved overall process stability. This paper describes the equipment operated at SSAB Raahe since August 2019 and compares performance against the traditional design of stave. This paper describes the new stave design and its technical and commercial benefits over other designs, supported by operational data.

Eustáquio Vieira Junior, Ternium Brasil, Brazil

Abstract:
COMPARATIVE ANALYSIS OF BLAST FURNACE COOLER SYSTEM PERFORMANCE WITH DIFFERENT PRESERVATION TECHNIQUES AND DESIGN CONDITIONS Blast Furnace 2 of Ternium Brasil steelmaking company, in Rio de Janeiro, started to operate in December 16th, 2010. During its service life, the cast iron stave coolers displaced into the blast furnace and the copper stave coolers deformed, generating the lost of refrigeration capacity of these cooling system components. This paper presents the evaluation of techniques used to maintain the stability of the equipment shell, emphasizing the aspects of fluid dynamics, maintenance methods and the thermal consequences in stave cooler bodies. The main results of this research are the best procedures to stabilize the cooler system in good conditions without causing damages in the Blast Furnaces shell, and improvements in actual maintenance techniques to preserve the equipment and extend its service life. Keywords: Blast Furnace; Stave Cooler; Fluid Dynamics; Computational Fluid Dynamics.

Alexander Redenius, Salzgitter Mannesmann, Germany

Co-Author:
Peter Juchmann, Salzgitter-Flachstahl GmbH
Alexander Redenius, Salzgitter Mannesmann Forschung GmbH

Abstract:
To reach the environmental goals 2045/2050, a fundamental reduction of CO2 emissions has to be achieved in all areas. The steel industry is one of the most energy intensive sectors, but also offers the highest and most energy efficient potential for CO2 migitation. Since 2015 together with Fraunhofer-Gesellschaft and in technical cooperation with Tenova S.p.A., Salzgitter AG has been developing its well-known SALCOS concept aiming at a stepwise and flexible decarbonisation of steel making by carbon direct avoidance (CDA). Here, green hydrogen will replace carbon as reduction agent and energy carrier. This most promising approach of low-CO2 steel production is based on proven industrial-scale technology, which could be implemented immediately. Today`s BF/BOF process will be substituted by a direct iron ore reduction/electric arc furnace (DRP/EAF)-route. The DR process is predestined for a flexible switch and mixture of natural gas and green hydrogen. Right from the beginning the use of CH4 offers a significant reduction in CO2 emissions by more than 60 %. After a complete transition to 100% hydrogen from renewable energy a total decrease of CO2 emissions by more than 95% is possible. The presentation will give an overview of the ongoing SALCOS-transformation at Salzgitter-Flachstahl GmbH and includes current demonstration and accompanying research activities.

Amaia Sasiain, K1-MET GmbH, Austria

Co-Author:
Katharina Rechberger, voestalpine Stahl GmbH
Andreas Spanlang , voestalpine Stahl GmbH
Hermann Wolfmeir, voestalpine Stahl GmbH
Christopher Harris, voestalpine Stahl GmbH

Abstract:
The iron and steel industry accounts for approximately one-quarter of the global industrial CO2-emissions. As the reduction potentials of the current steelmaking routes are rather low, the transfer towards breakthrough-technologies is essential to achieve the climate neutrality by 2050, in line with the European Green Deal. The hydrogen-based direct reduction in combination with an electric arc furnace is one of the most energy efficient approaches to accomplish a CO2-lean steelmaking process. Therefore, the state-of-the-art natural gas based direct reduction acts as a basis for the first step of this transition. This process is already operated with a syngas containing CO and H2 produced out of natural gas. The high flexibility of the DR-route allows the gradual substitution of natural gas by hydrogen and, in a long-term view, running the process with pure hydrogen. The aim of this work is the analysis of the hydrogen-based direct reduction process from a technical and economical point of view. The results obtained; as the energy- and reactants demand, CO2 reduction potentials and production costs; were compared with the blast furnace and direct reduction process with natural gas, considered respectively as the reference- and the bridge technology route between both processes. The techno-economic assessment performed here, conforms the basis for the roll-out plan on behalf of the decarbonization of the steel industry

Brett Belford, SMS group GmbH , Germany

Co-Author:
Tim Kleier, SMS group GmbH
Gawie Lötter, Metix (SMS group)
George Farmer, Metix (SMS group)

Abstract:
Factors Affecting Throughput and Configuration of an Open Bath Furnace for the Production of Hot Metal Brett Belford , George Farmer, Gawie Lötter , Tim Kleier 1 Abstract The decarbonization of steel making is of importance to support the limitations on global warming stipulated in the Paris Agreement. Multiple technology options are emerging in the race to minimize the historically CO2-intensive iron production stage. One leading candidate is the combination of the well-proven direct reduction of iron ore using a shaft furnace (referred to generically in this paper as a direct reduction plant or DRP) and an open bath electric furnace (OBF). The DRP-OBF technology stands out as a viable candidate to significantly lower the CO2 footprint of the iron making stage, meeting many criteria that other technology options are not immediately able to satisfy. In conjunction with real-world plant operators, the authors have undertaken a number of case studies exploring configurations of DRP and OBF for the iron making stage, both in existing-, and greenfield sites. These studies have revealed that potential plant operators often seek guidance on the primary factors influencing plant throughput, energy consumption, capital- (CAPEX) and operational expenditure (OPEX). OBF configuration and plant layout are inextricably linked to the throughput, and also to the associated risk of an inherently new scale of operation. Given that the DRP-OBF plant configurations are not well known, an opportunity arises to link throughput, configuration, layout and risk considerations in a single paper. Keywords: openbathfurnace, OBF, smelter, hotmetal, decarbonization, greensteel, sustainability, ironmaking

Rob van Opbergen, Danieli Corus, Netherlands

Abstract:
Title: Channelling in the blast furnace Oscar Lingiardi (1), Rob van Opbergen (2) and Maarten Geerdes(3) 1) Ternium, Argentina, olingiardi@gmail.com 2) Danieli-Corus, The Netherlands, Rob.van-Opbergen@danieli-corus.com 3) Geerdes Advies, The Netherlands, geerdes@mgeerdes.nl Channelling in a blast furnace is a local, preferential gas flow through an area with the lowest gas resistance. Channelling occurs frequently and has major impact in loss of chemical and physical energy of the gas. Most of the channelling starts along the wall of the furnace. Because of the inverse conical shape of the shaft a gap is easily formed when burden descends. Channels have a self-enhancing effect: a strong gas flow blows away materials, preventing materials collapse in the channel. Therefore channels are observable from strong decrease of the gas utilization, locally high heat losses and/or stave temperatures as well as pressure taps. Experience shows, that channels can be caused by irregular burden descent, because fast descent creates a gap between wall and burden. Irregular burden descent is caused by uneven melting of the cohesive zone. This can be caused by - Concentration of fines. - Drainage of primary slag because of poor melting. - Unstable burden descent. Remedial actions for channelling are the following. - In the very short run an operator will try to have the channels collapse by checking and operate at a lower blast volume. - In the long run, the occurrence of channels has to be prevented by having stable burden descent. The paper will show, that effects on ETA CO, stave temperatures, heat losses and pressure taps indicate the same channelling phenomenon. Remedial actions are discussed and operational examples will be given.

Lijia Wu, AG der Dillinger Hüttenwerke, Germany

Co-Author:
Rongshan Lin, AG der Dliinger Hüttenwerke
Dieter Senk, IEHK RWTH Aachen University
Alexander Babich, IEHK RWTH Aachen University
Stephan Hojda, AG der Dliinger Hüttenwerke
Pierre Van Dorpe, PAUL WURTH S.A.
Juraj Micák, PAUL WURTH S.A.

Abstract:
The blast furnace is nowadays still the main facility for metallic iron production in steel making. Because of the current economic and ecological situation, a stable operation aiming at lowing fuel consumption is strongly required. Thus, reliable thermal state prediction plays an important role in thermal control. Compared to the silicon content in hot metal, the hot metal temperature is considered to be more representative of the current thermal state. Hence, for model fine-tuning, many thermal state prediction models especially machine learning models require not only high measurement accuracy of hot metal temperature measurement but also enough datasets. This paper introduces first a short overview of methods of hot metal temperature measurement and presents secondly the model-based thermal control system applied at ROGESA. To further improve this system, continuous hot metal temperature measurements are installed for each of the two tap holes on blast furnace No.5. The results are compared with the conventional hot metal temperature measurements that are taken by immersion thermocouple probes and integrated into the current thermal control system for further improvement of thermal state prediction supported by machine learning. Key words: thermal control; hot metal temperature prediction; continuous hot metal temperature measurement; machine learning models

Eric Schaub, Paul Wurth Deutschland GmbH, Germany

Co-Author:
Ralf Allmannsdörfer, Paul Wurth Deutschland GmbH
Markus Bierod, Paul Wurth Deutschland GmbH
Volker Dulz , Paul Wurth Deutschland GmbH
Rudolf Hebel, Paul Wurth Deutschland GmbH
Martina Engelmann, Paul Wurth Deutschland GmbH
Stephan Bamberg, Paul Wurth Deutschland GmbH

Abstract:
Modern blast furnace (BF) hearth linings can reach life times of 15 years and more. During such a long BF campaigns, a number of lining properties and characteristics (e.g. thermal conductivity (TC)) can change unnoticed, if alkalis form potassic feldspars, especially in carbon hearth lining layers. Besides this, other phenomena like “heat resistances” can create unnoticed changes in the hearth side wall lining, too. One has to distinguish between positive heat resistances like “skulls” and heat resistances with a negative effect on the BF hearth linings like cracks, gaps, or partly destroyed lining structures, like “brittle layers”. It is hard to detect such changes of important lining properties with classical observation measurement techniques. Without identifying such changes, it is very difficult to calculate the important “true and real” hearth lining wear profiles in different measuring sections and measuring levels with a 2D- or 3D- mathematical FE model. Paul Wurth Deutschland GmbH (Paul Wurth) has developed so-called multipoint thermocouple sensor probes (MTP sensor probes) in combination with necessary heat flux probes, to detect such kind of unnoticed changes of BF hearth lining properties on the one hand and “heat resistances” in the BF hearth linings on the other. In order to detect such phenomena, the multipoint MTP sensor probes are installed deep in the BF hearth lining wall and work reliably throughout the whole BF campaign. The MTP sensor probes provide “online” the necessary calibration and reference points for the true and real lining wear calculation with a special tailor-made mathematical FE model. Aiming at monitoring the condition and extending the service live of modern blast furnaces, especially under today’s harsh technical and economic conditions, Paul Wurth presents in this paper examples of typical installations, recent experience of detected abnormalities as well as application of MTP sensor probe technology and mathematical models.

Fabian Perret, RWTH Aachen University, Germany

Co-Author:
Dieter Senk, RWTH Aachen / IEHK
Alexander Babich, RWTH Aachen/ IEHK

Abstract:
Despite measures to increase pulverised coal (PC) conversion, part of the injected PC leaves the raceway as char, particularly at high injection rates. The coke/PC replacement ratio and, consequently, the blast furnace (BF) operation efficiency depends on the consumption of char by reactions of sec-ondary gasification and added burden. This contribution focuses on the change in streaming condi-tions in different BF zones when coal particles leave the raceway. To investigate this, a 2-D physical BF cold model was used. Tests were conducted after injecting various amounts of PC and under various gas flow rates. Particle movement and accumulation were examined by measuring the pres-sure drop at different positions in the model. To evaluate the effect of PC on the gas permeability in vertical and horizontal directions, calculations using the Darcy-Weisbach/Ergun equation were per-formed. The results will be used to improve CFD-modelling and the prediction of char behaviour in the BF.

Bartosz Smaha, thyssenkrupp Steel Europe AG, Germany

Co-Author:
R. Klock, thyssenkrupp AT.PRO tec GmbH
C. Morrison, Primetals Technologies Limited
W. Edmond, Primetals Technologies Limited
H. Bartusch, VDEh-Betriebsforschungsinstitut GmbH
M. Juen, thyssenkrupp AT.PRO tec GmbH

Abstract:
The SIP technology developed by thyssenkrupp in-house is the first of its kind and the Schwelgern 1 blast furnace is the first blast furnace in the world to be equipped with it. The system fits perfectly into thyssenkrupp Steel’s strategy to produce carbon-neutral steel of known quality by 2045. The carbon-based metallurgy of the blast furnace route is expected to give way to hydrogen-based technologies. The SIP Oxygen Pulsing technology was commissioned in late 2020 on the 40-tuyere thyssenkrupp Steel Europe Schwelgern BF1 in Germany, and demonstrated immediate improvements in eta-CO. The technology makes it possible to optimize the use of reducing agents. Innovations such as the SIP process enable the necessary efficiency gains and CO2 savings in the existing infrastructure until the technology change is complete. This paper presents the effects of the new technology on the performance and CO2 emissions during regular operation of the blast furnace.

Rodrigo M. de Carvalho, Universidade Federal do Rio de Janeiro, Brazil

Co-Author:
Luis Marcelo Marques Tavares, UFRJ
Emerson Reikdal da Cunha, UFRJ
Rodrigo Magalhaes de Carvalho, UFRJ
Bruno Pinheiro da Silva, Ternium

Abstract:
In the BLT systems, metallic and coke raw materials are discharging in layers into the blast furnace. The quantification of granular materials characteristics into the blast furnace, such as granulometric segregation and components distribution are difficult to perform. Therefore, this work consists in the development of a predictive model for the understanding and optimization of the blast furnace burden distribution equipped with a BLT (Bell less Top) based on calibrated high-fidelity DEM simulations, which were used as a viable and less expensive alternative compared to full scale experiments. To perform the simulations of the blast furnace charging, calibrations of contact parameters for coke and sinter were done, additionally the calibrations of pellets and lump ore parameters available in the literature. The present work contemplates the construction of a realistic virtual model of the blast furnace installed in Rio de Janeiro. Particles size distribution close to real materials were adopted in the simulations. The DEM simulations results allowed for the improvement of a phenomenological burden distribution model based on Park et al. (2011). The model was based on three charging strategies and four strategies for the discharge of the BLT hoppers and was able to predict and to determine the burden profile obtained in DEM simulations when compared to the original model by Park et al. (2011).

Dong-Geun Kim, Hyundai Steel Company, Korea, Republic of

Co-Author:
Hyuk Kim, Hyundai Steel Company
Ho Jun Youn, Hyundai Steel Company

Abstract:
The flow of slag through the coke bed largely influences the gas permeability in the dripping zone. The controlling parameters during the furnace operations are found to show a noticeable correlation with the conceptual slag holdup index. The relationship between the slag holdup index and plant data from the blast furnace (inner volume of 5250 m3) at the Hyundai Steel Company is analyzed. A practical range of the holdup index is derived based on three months of plant data. All the monitoring values in the furnace operation such as temperature, pressure from sensors, and the compositions/physical properties of the burden materials, etc. are used as-is. The mean size of the coke in the lower part of the furnace is predicted based on several times of coke sampling from the tuyeres. The voidage of the coke bed is derived from the measurement of the size distribution ratio of coke charges. A thermochemical software FactSage is used to calculate the slag viscosity. The guideline of operational parameters such as CaO/SiO2 basicity, wt%Al2O3 in burden materials, and the mean diameter of the coke charge are obtained in terms of the slag holdup index.

Christian Weichbold, voestalpine Stahl Donawitz Gmbh / K1-Met GmbH, Austria

Co-Author:
Elmar Schuster, voestalpine Stahl Donawitz GmbH

Abstract:
Sinter is a dominant operational material for the blast furnace and represents a continuous inhomogeneous material flow. Depending on the process step, different material flow structures can be found in the material flow. In order to be able to describe such material flow and its relevant attributes, sub-areas were analyzed in the SmartSinter-project and a model concept was developed. Sieves and conveyor lines can be relatively easily overserved and described in terms of material flow. Sinter coolers or bunkers in the stock house pose a challenge, as their interior cannot be observed. In order to examine the flow characteristics of these sub-areas, a physical bunker section model, bunker simulation (DEM) and tracer studies (RFID & color tracer) were used in the operating facilities. A transition function for the material flow was found for the cooler. This function describes the system’s response when input properties change. In the storage bunker area, we investigated the applicability of the RFID-technology. In the bunkers there is a pronounced core flow, which was confirmed with all three used methods. The DEM-Simulation was able to quantify this core flow and also provided important information about the segregation process when filling and emptying the bunker. Coarse material collects near the bunker wall, while finer parts concentrate in the core (center). In the first phase of emptying the bunker, more fines dominate and in the final phase the coarse fraction is discharged. So it was determined that the original smooth grain distribution leaving the sinter plant fluctuates greatly after the bunker system. Online measurement techniques for determining the grain size distribution were investigated and the challenges of these systems were explained. The observed different chemical analyzes in the individual grain classes and the findings from the bunker investigations can influence the downstream blast furnace process.

Thomas Steinparzer, Primetals Technologies GmbH, Austria

Co-Author:
Alexander Fleischanderl, UP TI

Abstract:
Energy and environmental technologies become a decisive factor for iron and steel industry. Emissions as well as energy efficiency directives are issued by every government in the world and the requirements become more stringent from year to year. For sinter plants the patented MEROS® technology has become a recognized solution and has recently been extended to by-product treatment to achieve almost zero waste. For direct reduction technologies dry dedusting and waste heat recovery are also the basis for modern production. The dry gas cleaning technology (MEROS) reduces the emissions of SO2, heavy metals and dioxins from sinter plants safely below the required emission levels all around the world. Such low emission levels are maintained by a multi-component additive injection upstream of a high-performance fabric filter, while the installation of a (selective) waste recirculation technology minimizes the investment cost for the gas treatment and reduces the fuel consumption. Residues and by-products arising from the gas treatment are often disposed, leading to consumption of valuable landfilling volume and high cost. The innovative leaching process is closely linked to the MEROS plant and reduces on site the residue volume to a minimum. The proposed solutions can be applied to existing and greenfield plants. This novel residual treatment technology has been applied in past year at a Japanese steel plant. Direct reduction technologies will see a booming market perspective due to their significant reduction of carbon dioxide emissions compared with other ironmaking technologies. A new dry dedusting system based ceramic filter elements as well as waste heat recovery boiler helps plant operators to undershoot all emission and energy efficiency requirements. The paper will summarize state-of-the-art environmental solutions as well as achievable performance figures including operational results and give an overview on the latest executed projects in a brown-field as well in a green-field environment.

Yakov Gordon, Hatch, Canada

Abstract:
Beginning of development of gas based direct reduction processes goes back to the end of 19 century. The first industrial application was Wiberg-Soderfors DRI shaft furnace process. The history of development and implementation of various gas based direct reduction processes was studied. The strength and week features of this processes were evaluated. It was shown that economics of the direct reduction process depends on cost of raw material and reducing agent, reliability of equipment and strict application of direct reduction principles. Deviation from these main principles leads to the failure of the new DRI technologies. Results of evaluation allowed to show, why Midrex and HYL are the only successful DRI gas-based processes, while other lost their competitive position and stop operation.

Hesham Ahmed, Lulea University of Technology, Sweden

Co-Author:
Bo Björkman, Luleå university of Technology
Johanna Alatalo, johanna.alatalo@afry.com
T K Sandeep Kumar, LKAB
Hesham Ahmed, Lulea University of Technology

Abstract:
Iron and steel industries are major contributors to the greenhouse gas emissions. The majority of these emissions are linked to the use of fossil-based carbon. Hence, decarbonization of the steel industry is one of the pathways toward a fossil-free environment. One of the decarbonization strategies is to replace the fossil-based reductant by green hydrogen. However, the produced zero-carbon DRI will cause the refining and steelmaking operations to have a starting point far from today’s operational practices. The furnace feedstock melting point will be increased by several hundred degrees, melting will take place over a very short melting interval, gas formation in the melt will be very limited, and slag foaming will be difficult to achieve without introducing additional carbon. Therefore, in hydrogen-based iron making process, a way to introduce carbon in a controlled manner is essential. In the present study, attempt have been made to investigate the carburization of hydrogen-reduced DRI at the single pellet scale. The factors affecting the carburization process, such as gas composition, temperature and duration were investigated thoroughly in the temperature range of 600 to 800oC. Further, the carbon introduced into the hydrogen-reduced DRI can either be in the form of cementite, graphite (free-carbon) or mixture of both. Therefore, the effect of carbon content and the form in hydrogen-based DRI for their respective melting characteristics have also been investigated, and presented here.

Hannah Lomas, The University of Newcastle, Australia

Co-Author:
Hannah Lomas, University of Newcastle
Richard Roest, University of Newcastle
Hui Wu, University of Wollongong
Zhengyi Jiang, University of Wollongong
Richard Sakurovs, CSIRO Energy
Aaron Anderson, University of Newcastle
Anthony Edwards, University of Newcastle
Tori Hill, University of Newcastle
Merrick R. Mahoney, University of Newcastle
Arash Tahmasebi, University of Newcastle
Brody Brooks, University of Newcastle

Abstract:
One of the major reasons it is difficult to predict the strength of metallurgical coke is its heterogeneity. The mechanisms by which coke degrades under applied loads or stresses are not only dependent on coke composition and microstructure but also the different forms of carbon that the coke comprises, which constitute the coke microtexture. Furthermore, the ordering of the carbon domains within the microtextural constituents and the integrity of the interfaces between them are key contributors to coke strength, including its resistance to abrasion. We have developed a novel approach which applies tribological (i.e. wear) testing techniques to examine the factors that influence coke abrasion. Moreover, we have developed the capability to assess coke abrasion resistance in-situ at elevated temperatures of up to 950°C and in controlled gas atmospheres. Bosh coke samples retrieved from an operating blast furnace and a near-matched feed coke were examined in this study. The key findings include: • High temperature abrasion resistance for both cokes was lower than at room temperature. Parallel work has shown that the reduction in abrasion resistance occurs for both the RMDC and IMDC, and at interfaces. • CO2 attack during pre-reaction of feed coke samples was found to ‘level’ coke properties, to some extent, and effectively overwrite the effects of prior CO2 exposure in the blast furnace. • Bosh coke IMDC showed more severe damage than in feed coke at 950°C, suggesting that the thermal damage to the IMDC is accentuated by prior gasification. • In the blast furnace, the fines generated by abrasive wear may act as a lubricant or they may adversely impact the permeability of the furnace and thus its efficient operation. • A parallel study using pilot oven cokes from single Australian coals of varying properties has indicated that deterioration in abrasion resistance occurs at 400°C, and is accentuated at 950°C.

Marc Schulten, thyssenkrupp Steel Europe AG, Germany

Co-Author:
Heike Liszio, thyssenkrupp Steel Europe AG
Oliver Donnes, thyssenkrupp Steel Europe AG
Viktor Stiskala, thyssenkrupp Steel Europe AG

Abstract:
thyssenkrupp Steel Europe (tkSE) operates a pilot coke oven lab in Duisburg. Main target of the lab is to support the operations of coke plant Schwelgern. The lab can only be an assisting to plant operations if the pilot ovens produce comparable data. This includes also coke parameters such as texture and phase distributions. To get additional insight tkSE was participating in the research project ForeCoke. The paper outlines the carried out comparison study between industrial and pilot oven coke and detectable impacts on coke quality.

Maria Lundgren, Swerim AB, Sweden

Co-Author:
,
Lena Sundqvist Ökvist, Swerim AB

Abstract:
The use of processed biomass (bio-coal) as source for carbon in the reduction of iron ore to metallic iron in the blast furnace is one option for decreasing the CO2 emission from integrated steel plants. Trials with addition of bio-coal to the coal blend for cokemaking have been conducted in technical scale at DMT retort with different types of bio-coals and amounts. Characterization of bio-coal as chemical composition and produced bio-coke involves changes in strength, reactivity and microstructure as well as dilatation, maximum fluidity and estimated wall load compared to reference coke and blend. Potential usage of bio-coal as partially replacement of coking coals and possible methods for maximizing the added amount are discussed.

Anne Heikkilä, University of Oulu, Finland

Co-Author:
Timo Fabritius, University of OUlu
Mikko Iljana, University of Oulu
Aki Koskela, University of Oulu

Abstract:
A blast furnace (BF) is the dominant process for making iron in the world. The blast furnace is charged with coke and iron burden materials including iron ore pellets, sinter and/or lump ore. Coke has several functions in blast furnace process. Coke acts as a fuel in the blast furnace, it acts as a reducing agent for iron bearing materials and it provides support for the charge material inside the blast furnace providing permeability structure that enables gases to flow upwards. Compression strength of coke is one way to describe coke’s ability to act as a skeleton of the blast furnace charge. This work focuses on the compression strength of two different coke types after gasification. The gasification experiments were conducted in two different dynamic atmospheres acquired from an actual industrial blast furnace (CO-CO2-N2 and H2-H2O-CO-CO2-N2). Compression strength after reaction was studied with Gleeble 3800 thermochemical simulator. Light optical microscopy was used together with image analysis to gather information about pore area. Differences were found in pore areas as well as in compression strengths between the coke types as expected. Furthermore, the differences in atmospheres (with/without H2 and H2O) also yielded different results making strain at breaking point happen to a narrower scale when hydrogen and water vapor were presence at the atmosphere.

Arash Tahmasebi, The University of Newcastle, Australia

Co-Author:
Stephen Brant, BHP
Kim Hockings, BHP
Brody Brooks, University of Newcastle
Apsara Jayasekara, University of Newcastle

Abstract:
The importance of reducing CO2 emission linked with blast furnace ironmaking is widely recognised. Among proposed strategies to reduce CO2 emission, partial replacement of coal by biomass in coal blends has gained increasing interest. Woody biomass, such as charcoal and torrefied biomass used in previous studies, was identified to negatively impact coal rheology and coke strength due to the fibrous nature of these species. This paper introduces the use of microalgal biomass to the coking blend to increase the share of renewable carbon in cokemaking. Microalgae species are primarily composed of lipids, proteins, and carbohydrates, which, unlike woody biomass, do not form a fibrous structure during the carbonisation process. This is expected to mitigate the negative impact of biomass addition on coal rheological properties and coke strength compared to woody biomass. Microalgae can also be produced locally on a large scale for bio-fixation of CO2 from off-gas streams in integrated steel mills. The paper evaluates the impact of the addition rates of up to 10% microalgae Chlorella Vulgaris on the fluidity behaviour of three Australian metallurgical coals varying in rank, fluidity, and maceral composition. Custom-designed laboratory-scale experimental facilities including the 4kg dual-heated coke oven and permeability/ dilatation test facilities were utilised to measure thermoplastic parameters, including the plastic layer permeability, thermo-swelling, and internal gas pressure. The experimental results showed that the thermoplastic properties of premium Australian metallurgical coals were largely unaffected by microalgae addition, while a deterioration of thermoplasticity was recorded for the semi-hard low-vitrinite coal. The research outcomes provide guidance in selecting appropriate parent coals for microalgae blending.

Priyanthi Hapugoda, CSIRO, Australia

Abstract:
The reflectance measurements of macerals have a prominent role in the assessment of coals. As vitrinite reflectance is used as a rank index, the reflectance of all macerals can be used to predict a coals behaviour during coke making. Whilst these measurements are traditionally done manually, semi-automated imaging and characterisation methods provide an alternate means for acquiring this information. CSIRO have developed a semi-automated optical reflected light imaging and analysis system, Coal Grain Analysis (CGA), which provides high resolution reflectance and composition information on a large individual coal particles. This paper presents the process of vitrinite reflectance analysis of coking coal samples using this system to complement the traditional manual process which have some inherent limitations. First, continuous calibrated high-resolution images are collected across the settling plane on standard petrographic grain mounts in immersion oil using a 20X oil immersion objective following the standard calibration procedure similar to that detailed in [6]. The mosaicked images are then processed to obtain reflectance information, size, and compositional information for each individual particle in the image. The CGA processing software can export random reflectance measurements of vitrinite as well as inertinite information from individual particles. This provides reflectance information for tens of thousands of individual particles in a single sample; significantly higher than what is obtained by the industry standard manual method. This reflectance information can be used to compile maceral reflectance histograms which provides unique information to the industry for assessing the contribution of each of the macerals to coking performance.

Luke Balzan, Scantech International, Australia

Co-Author:
Henry Kurth, Scantech International

Abstract:
Accurate and timely control of a process is critical in the iron and steel making industry. As sensor technology improves and develops, controlling a process in real time becomes more viable and is essential for a modern plant to ensure optimal performance. Scantech's GEOSCAN range of elemental analysers have been used for more than two decades in a range of different industries, including both iron ore and for active real time control of cement plants. Using its extensive experience in these two industries, Scantech has been able to adapt the GEOSCAN for accurate real time measurement of sinter feed. From the elemental composition, basicity can be calculated and used for control. The high specification of the equipment enables accurate analysis of all the critical elements: silicon, aluminium, calcium and magnesium, which in turn enables better measurement of basicity and thus control via limestone dosing and additives. This paper discusses how the GEOSCAN is used, as well as giving a number of European examples where the equipment has been successful in improving control of sinter feed basicity.

Rongshan Lin, AG der Dillinger Huettenwerke, Germany

Co-Author:
Nadine Ziegler, AG der Dillinger Huettenwerke
Benjamin Blaß, AG der Dillinger Huettenwerke
Dieter Georg Senk, RWTH Aachen

Abstract:
Sinter is the major iron-bearing burden material in many integrated steelworks worldwide. Therefore, the sinter quality is of crucial importance for the blast furnace operation. The sinter production is usually monitored by periodic testing of the chemistry and metallurgical properties. However, the sinter properties are dependent not only on the chemical composition, but also strongly on the phases present after sintering and cooling, Sinter has a multiphase microstructure. Some phases are also multicomponent systems. The amount and morphology of the crystalline phases, amorphous phases and pores play an important role in the sinter properties. Experimentally, it is not possible to cover all these features with only one characterization technique. Therefore, in this work the microstructure of an industrial sinter was characterized by means of light microscopy, scanning electron microscopy (SEM), also using the chemical elemental mapping by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results of each technique are complementary and are discussed together to provide a broader picture of the sinter microstructure of an industrial sinter.

Roland Mežibrický, K1-MET GmbH, Austria

Abstract:
Ideal phase assemblages in the sinter matrix are essential for a high-quality sinter in terms of its strength. Individual mineral phases are considered as suitable or not suitable for a high sinter strength, however, there are limitations of the chemical composition because of the blast furnace requirements. Furthermore, sinter with e.g. calcium ferrites as the only bonding phase is almost impossible to produce. In this study, phase assemblages of industrial sinter were examined and coupled with the productivity index of a sinter plant. The results showed a strong relationship between the sinter quality and the sinter matrix. The phase assemblages influence the initial melting conditions as well as the strength after crystallization. The expected negative impact of silicates was found to be suppressed if appropriate phase assemblage formed in the sinter matrix. A simple calculation tool for the prediction of the sinter matrix composition and related sinter productivity has been developed.

Daisuke Maruoka, Tohoku University, Japan

Co-Author:
Tsubasa Shima, Tohoku University
Taichi Murakami, Tohoku University
Eiki Kasai, Tohoku University

Abstract:
Reduction of CO2 emissions has been strongly required for the ironmaking processes. In the sintering process of iron ores, coke breeze is utilized as main agglomeration agent. Its replacement with iron bearing materials such as metallic iron, wustite and magnetite is a promising way to reduce CO2 emissions from the process. Most of coke particles disappear due to combustion, while iron bearing materials remain in the sintering bed as their oxidized phases after heat generation through their oxidation reactions. Therefore, iron bearing materials will significantly affect the permeability of sintering bed and quality of produced sinter. Since the oxygen partial pressure in the sintered bed decreases with the combustion of coke, it is necessary to understand the oxidation behavior of the iron bearing materials under lower oxygen partial pressure conditions. In this study, influence of oxygen partial pressure on the high temperature oxidation of metallic iron was examined to evaluate the possibility to utilize it as an agglomeration agent. Thin plate samples of metallic iron were heated up to 1200℃ under N2 atmosphere by using TG. After reaching to the holding temperature, atmosphere was changed to the oxygen partial pressure of 0.001 - 0.21 atm, which was controlled by using N2 or CO2 gas. Thickness of wustite layer formed at the sample surface increased up to 300 s and follows parabolic manner. The wustite layer thickness decreases after 300 s, instead the thicknesses of magnetite and hematite layers drastically increased. It appears that the rate-determining step is changed when all metallic iron is oxidized to wustite. At PO2 = 0.01 atm, only wustite layer is observed and the oxidation proceeds in the CO2 base than in the N2. It implies that O2 is supplied by the decomposition reaction of CO2 gas.