Ahmed, Dr. Hesham, 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.

Alter, Dr. Michael, ALTER Blast Furnace Consulting, United States

Co-Author: Vladimir Naboka, PJSC “Zaporizhstal” Iron & Steel Works • Sergey Safonov , PJSC “Zaporizhstal” Iron & Steel Works • Sergey Karikov, PJSC “AZOVSTAL” Iron & Steel Works • Oleksii Chaika, Iron and Steel Institute of Z.I. Nekrasov National Academy of Sciences of Ukraine • Vitaliy Lebed, Iron and Steel Institute of Z.I. Nekrasov National Academy of Sciences of Ukraine • Bohdan Kornilov, Iron and Steel Institute named Z.I. Nekrasov National Academy of Sciences of Ukraine (ISI NASU);

Abstract: The implementation of Pulverized Coal Injection (PCI) technology has reduced the lifetime of lining and cooling systems on Blast Furnaces in Ukraine. Efficient long-lasting operation with PCI required a new approach to furnace design and systems to control technical condition and thermal work of blast furnaces. Six blast furnaces of “MetInvest” have been upgraded to work with 160 kg/t PCI since 2014. These changes include: shaft cast-iron cooling plates replaced with copper; evaporative cooling system updated to modern cooling system having "cold" chemically purified water; profile design changed and furnaces equipped with Bell Less Top (BLT). In accordance with proposals of the Institute of Ferrous Metallurgy of National Academy of Science of Ukraine these blast furnaces were equipped with automated monitoring scheme of shaft-lining wear and in the hearth, thermal losses in the cooling system and also providing coke compensation calculations. One of the furnaces was equipped with the BLT charging model make available burden calculations and distribution. The mathematical models provide operators with critical information impacting the furnace operations on lining wear, skull formation, heat loads and losses on the shaft and hearth. This information is used for decision-making on optimization smelting regimes with PCI, which ensure the performance and efficiency while maintaining a lining and ensuring the safety of blast furnace operation. The automated system characterized the cooling system heat losses with 10 - 45 kg/t of coke required for compensation and established the dependency of blast furnace design and technical condition, loading parameters and operations technology. A reduction of specific coke rate of 2 – 20 kg/t was realized using the BLT charging model (varying by actual conditions.)

Altgaßen, Jan, 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.

Aubry, Nicholas, Hatch, Canada

Co-Author: Don Tu, Hatch Ltd. • Ian Cameron, Hatch Ltd.

Abstract: The addition of DRI to the Blast Furnace (BF) has known benefits for increasing productivity and decreasing coke rate. The impact of DRI additions has been revisited as a strategy to reduce blast furnace CO2 emissions. Technology changes are needed to overcome the challenges of low top gas temperature. We estimate the maximum amount of DRI that can be added to a blast furnace operation and the related carbon dioxide savings. BF operational strategies of various regions around the world dictate the maximum DRI charge to the BF and resulting CO2 saving. A discussion on how operational strategies can be modified to charge more DRI is provided.

Aubry, Nicholas, 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.

Aubry, Nicholas, Hatch, Canada

Abstract: Tuyere zone blast furnace reactions are reviewed from an energy standpoint. Simplified mass and energy balances are outlined to improve the accuracy of flame temperature calculations.

Bahgat, Dr. Mohamed, Hadeed a SABIC Affiliate, Saudi Arabia

Abstract: One of the challenges facing steel producers that rely on direct reduction technologies is the sticking tendency of iron ore pellets, which might lead to disrupting operational procedures. In an effort to reduce the sticking tendency of iron ore pellets, suppliers apply inactive coating materials and steel producers apply an additional coating in the form of slurry prior to charging pellets to the furnace. In this work, the suitability of steel plant’s by-products to be used as a secondary coating material is investigated. In order to determine the optimum coating conditions, their influence on pellets reducibility and sticking index was quantified. The coating condition in question includes dosage amount and slurry concentration of the coating material. Coating amounts were varied in the range of 1-5 kg per ton of ore and slurry concentrations were varied in the range of 5-30% in this study. Thermogravimetric analysis was used to measure the relative reducibility of the pellets under different coating conditions. The reduction conditions were set to simulate reduction temperature and reducing gas composition in Midrex shaft furnace. The samples that exhibited higher reducibility were those at coating condition of: • 20% slurry conc. & 3.0 Kg /ton iron ore • 30% slurry conc. & 3.0 Kg /ton iron ore • 30% slurry conc. & 4.0 Kg /ton iron ore Sticking index measurements were determined according to ISO 11256 for these samples that showed relatively higher reducibility. Since the samples showed similar sticking index values, an additional optimization analysis in terms of operational cost was carried out. It was concluded that the coating conditions with optimum reducibility and adequate sticking resistance are 3.0 kg per ton of ore and 30% slurry concentration.

Balzan, Dr. Luke, 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.

Baniasadi, Dr. Mehdi, Paul Wurth, Luxembourg

Co-Author: Cristiano Castagnola, Paul Wurth • Maryam Baniasadi, Paul Wurth • Klaus-Peter Kinzel, Paul Wurth • Philipp Bermes, Paul Wurth • Florent Mauret, Paul Wurth • Stephan Hojda, Dillingen Hutte • Rongshan Lin, Dillingen Hutte • Henrik Saxon, Abo Academi

Abstract: Although concepts for future carbon neutral steelmaking with green hydrogen are on their way, their economic feasibility is often not yet given. Enhancing the traditional BF-BOF route, responsible for 70% of steel production, towards CO2 saving is, therefore, of vital importance. A key technology for significant CO2 emission reduction of the blast furnace is to inject hydrogen-rich syngas at the shaft level. This injection enables high injection rates of hydrogenous gases such as coke oven gas, natural gas, and syngas at the tuyere level. Nevertheless, the influence of hydrogenous gas injection through tuyere and shaft on the BF internal state and overall performance needs to be thoroughly investigated before industrial application. Considering the hostile environment inside the furnace, numerical modelling is the most promising approach for acquiring the required knowledge. In this contribution, a newly developed two-dimensional and multiphase mathematical model for describing the flows and thermo-chemical behaviour of a BF is used. A thorough validation of the model has been carried out using operational data such as in-burden measurements and top gas conditions. Simulations were then carried out to predict the effect of gas injection into the BF shaft. The results show that the shaft injection brings the cohesive zone root up while remaining controlled below the syngas injection point. An increase of the reduction degree and gas temperature in the wall region is also observed. This study demonstrates the potential of the newly developed numerical model to quickly and accurately investigate innovative BF processes with minimum CO2 emissions also for cases of high hydrogen load and low coke rate.

Bartusch, Dr. Hauke , VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author: Tatjana Mirkovic, Salzgitter Flachstahl GmbH • Marcel Kloos, Salzgitter Flachstahl GmbH • Matthias Kozariszczuk, VDEh-Betriebsforschungsinstitut GmbH • Thorsten Hauck, VDEh-Betriebsforschungsinstitut GmbH • Hauke Bartusch, VDEh-Betriebsforschungsinstitut GmbH • Pavel Ivashechkin, VDEh-Betriebsforschungsinstitut GmbH

Abstract: The dust in the blast furnace top gas has for a long time been regarded only as a process residue which must be handled somehow. Correspondingly, little attention was paid to the time course of the dust concentration - although it carries important information about the furnace’s working state. Excessive dust generation was proven to signalise upcoming operational issues which detract efficiency and production. A proper combination of online dust supervision and fingerprinting with operational data evaluation allows to predict operational problems in advance. This early error recognition enables to improve process control and efficiency: good reason to monitor the dust formation. Therefore, VDEh Betriebsforschungsinstitut has developed an online top gas dust concentration measurement system based on the soft-sensor principle. In the first step, part of the top gas is washed in a small scrubber and the slurry is directed to the MAGS sensor. The mass of dust separated on a magnet is continuously measured. In the second step, this value is transformed by a software model to the information about the total dust concentration in the top gas to deliver continuous knowledge about the current furnace state. The sensor MAGS has been applied to blast furnace B at the Salzgitter Flachstahl site. The obtained data reveals new information about the dust formation during charging of different materials, but also about the dust concentration arising from the process in between the chargings. A clear relation between dust formation and process state could be shown. Proper interpretation of the MAGS measurements enables a new facet of blast furnace working state monitoring. This article informs about the technical concept of the soft-sensor and provides an insight about the so far received knowledge from analysis of the obtained data. The sensor is currently in a long-term trial at the Salzgitter Flachstahl site.

Baumann, Thomas, AKW Apparate + Verfahren GmbH, Germany

Co-Author: Thibaut Richard, AKW Apparate + Verfahren GmbH

Abstract: Almost all the iron and steel manufactured in the world is made from pig iron produced by the blast furnace process (BF). However, the dust and especially the sludge represent a great challenge to improve the overall sustainability of this highly material and energy intensive industry. During the production of pig iron in blast furnace, a Zn- and Pb-containing sludge is generated in the air pollution control system. More than ½ of the mass input becomes outputs in form of off-gas and solid wastes/by-products. This toxic waste can be landfilled after dewatering and pretreatment, which is very costly. The sludge particles contain large amounts of Fe and C that could be recycled in the furnace. However, the Zn content of the sludge is high, and the Zn input to the blast furnace must be limited, so Zn has to be removed (major portion concentrated in the <20 µm). There are no standard plant concepts for a BF-sludge treatment plant. The process design and plant arrangement will primarily depend on the nature of the feed sludge and therefore will be based on pilot test work that is being performed in AKW Equipment + Process Design technical laboratory. On basis of the test results, the suitable and customized process solution will be developed, discussed and later on engineered and executed by AKW Equipment + Process Design. This unique process concept is presented in the following paper: multi-stages hydrocycloning, combined with thickening and filter pressing.

Belford, Brett, 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

Bettinger, Dieter, Primetals Technologies, Austria

Co-Author: Harald Fritschek, Primetals Technologies • Martin Schaler, Primetals Technologies • Petra Krahwinkler, Primetals Technologies • Adnan Husakovic, Primetals Technologies

Abstract: The revival of Artificial Intelligence (AI) promises to offer solutions in particular for complex systems that are difficult to model with classical methods. An overview of AI solutions in ironmaking is provided, their strengths and weaknesses are discussed: Topics as the applicability for typical problem groups, preconditions regarding required data quality and completeness of data sets, reliability, combination with classical approaches are covered. Further the deployment and integration of black box models into control systems and the related stability are discussed.

Boyle, Sean, Midrex Technologies, Inc, United States

Abstract: The mitigation of greenhouse gas (GHG) emissions is becoming critical in the steel industry. The natural gas based MIDREX® Process paired with an electric arc furnace (EAF) has the lowest CO2 emissions of any ore-based steelmaking route with options to lower even further. As green hydrogen becomes available, it can be injected in the MIDREX process with minimal modifications, thus reducing emissions further. Ultimately, MIDREX H2™ can make use of hydrogen both as the energy source and the reductant to produce a near-zero carbon footprint metallic, which can then be used as feedstock for steelmaking. The ArcelorMittal Hamburg project will be the world’s first direct reduction plant on an industrial scale to demonstrate the technology readiness. Unfortunately, green hydrogen is not currently available at sufficient scale and low cost for rapid adoption. Additionally, the capital requirements to convert from BF to DR-EAF are enormous. Therefore, the rapid conversion to hydrogen steelmaking is unrealistic, so other ways to reduce CO2 emissions during the transition phase must be explored, such as the use of HBI in a BF/BOF. Hot Briquetted Iron (HBI) is a compacted form of Direct Reduced Iron (DRI) that is manufactured with well-defined, consistent chemical and physical characteristics that make it very suitable for handling, shipping, and storage with minimal yield losses during those steps. HBI can be used in an EAF to produce high quality steel products and in Blast Furnaces to increase productivity and lower coke consumption, ultimately lowering CO2 emissions. As such, HBI produced outside of one’s facility should be considered in all steelmaking operations as a flexible metallic source during the hydrogen transition. As a merchant product, HBI can be produced in large scale operations at a location where logistics and reducing gas (including hydrogen) can be advantageous and transported in the right amount to

Brockmann, Dr. Stefanie, Steel Institute VDEh, Germany

Abstract: Welcome address by the host

Brooks, Brody, The University of Newcastle, Australia

Co-Author: Stephen Brant, BHP • Kim Hockings, BHP • Soonho Lee, University of Newcastle • Brody Brooks, University of Newcastle

Abstract: Maceral composition is one of the key parameters used to assess coals and to predict coke quality. However, coal grains are often a mixture of different macerals and mineral matters. The development of fluidity in coal grains depends on grain size and the degree of maceral association. It is important to determine the composition of coal grains to understand the fluidity drivers. Coal Grain Analysis (CGA) was used in this study to determine the maceral compositional information of individual coal grains for 4 metallurgical coals varying in rank and maceral composition. The thermoplastic behaviour of coal samples was tested using a Gieseler plastometer and the custom-designed permeability/dilatation testing apparatus and a 4kg dual-heated coke oven. The experimental results showed that coal inertinite content and the degree of association between inertinite (and minerals) and vitrinite greatly influence coal thermoplasticity. Coals with a lower vitrinite particle size and a higher degree of association of vitrinite with inertinite and minerals showed lower dilatation and higher permeability. It was postulated that coals with close maceral association are more prone to volatile gas escape during the plastic phase, effectively hindering bubble formation and growth and thermoswelling while also increasing the viscosity, leading to decreased Gieseler fluidity measurements. However, coals with different degrees of maceral associations showed similar internal gas pressures (IGP) in the 4kg dual heated coke oven and made strong cokes. The liquid phase present in the melt provided sufficient binder material to form strong cokes. Results suggest that some coals possess a higher “effective fluidity” than reported from standard Gieseler testing. On the other hand, coals that display limited maceral association and relatively high proportions of larger vitrinite prolific grains benefit from enhanced bubble growth and coalescence. The apparent fluidities of such coals are more accurately represented by standard Gieseler testing.

Chaigneau, Dr. Rénard, Baffinland, Netherlands

Co-Author: Maarten Geerdes, Geerdes Advies

Abstract: Numerous studies have been done to determine the best properties of each of the components of the blast furnace ferrous burden like for sinter, for pellets or for lump ore. The more difficult and interesting question is: how does the burden as a whole behaves inside the blast furnace when facing reduction, softening and melting. More difficult, since studies inside the furnace are nearly impossible and laboratory simulations never can cover the complete process. The present paper shows data that have become available from analysis inside the furnace as well as resulting from laboratory tests. The following conclusions are reached: - Reducibility: it was found, that the reduction degree of materials with very different reducibilities are at 900-950 °C more or less identical. Furthermore, reducibility is the weighted average of the properties of each of the components. - Softening of a blend is much closer to the softening temperature of the material with the highest softening temperature. Softening and melting of a blend is not a weighted average of the properties of each of the components. An example is shown, where in a blast furnace the pellet ratio is increased and what options exist with respect to pellet type (fluxed, acid, olivine) in conjunction with sinter basicity. The conditions for burden distribution at high pellet% are indicated and a strategy for using lump ores under varying conditions is discussed. Understanding the interaction of reduction, softening and melting in conjunction with burden distribution is important as they are main contributers to blast furnace productivity. The inherent know how on ferrous burden should also be applied to existing and newly developed shaft based direct reduction processes

Chen, Prof. Guanjun, Research Institute of Technology in SHOUGANG Group, China

Abstract: The energy consumption in iron-making process accounts for the main part of the total energy consumption in iron and steel industry, which is the focus of iron and steel energy conservation. Hot blast stove technology and blast temperature in China have greatly improved after more than ten years introduction, digestion and absorption, and independent innovation, but there has been a decline in recent years. According to the basic methods to improve blast temperature, the relationship between theoretical combustion temperature, preheating temperature and calorific value of gas is discussed. Through the comparison of domestic and foreign technologies such as blending high calorific value gas, preheating by heat exchanger, preheating by hot blast stove itself and preheating by high temperature air combustion, etc. It is clarified that high blast temperature of 1250 ~ 1300 ℃ has been achieved by adopting the double preheating technology of air and gas with high temperature preheating furnace on the hot blast stove of large blast furnace. In combination with the problems of cracking of furnace shell, deformation of corrugated compensator and corrosion of gas pipe network in the hot blast stove of JINGTANG No. 2 blast furnace(5500m3) in recent years, measures such as controlling the top temperature, surface temperature and displacement monitoring of expansion joints are taken to improve the blast temperature. Through comparison of main blast furnace indexes before and after raising the blast temperature in 2014 and 2016, it is shown that the blast temperature has picked up somewhat in recent years and the energy consumption level has decreased. The research on blast temperature uniformity shows that the method of stabilizing blast temperature can effectively improve the average blast temperature. The influence of parameters such as the temperature of combustion-supporting air before and after raising the blast temperature, the preheating temperature of gas, the calorific value, the flow rate, the dome, the blast temperature and the smoke exhaust temperature on raising the blast temperature were emphatically studied. At the same time, it is pointed out that there is a technical problem to realize high blast temperature for a long time and there is a long way to go.

Chomyn, Kyle, 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.

Cremer, Michael, 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.

de Graaff, Bart, 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.

de Graaff, Bart, Danieli Corus, Netherlands

Abstract: NOx emission from the Hot Blast System: Formation, effects, and the possibilities for its reduction Bart de Graaff, Jan de Weerdt, Yuriy Lytvynyuk (Danieli Corus) Keywords: Hot Blast Stoves, Hot Blast System, NOx formation, Emissions, Inter–crystalline Stress Corrosion INTRODUCTION The environmental footprint of the production of iron and steel is well–known by the industry and in general large improvements have been made in this field over the past decades [ref. 13]. However, in many places iron and steel companies are still a significant source of water and air pollution. With growing concerns from local societies over harmful emissions and the tightening of environmental regulations the need for mitigation remains high and important. One of the emissions that often gains attention of the ironmaking industry is the group of nitrous oxides, or NOx. This pollutant is formed within many of the present combustion processes, but one of its main sources and points of concern in the iron and steel industry is the Hot Blast System. Not only due its negative impact on the environment, but also because its influence on the occurrence of inter–crystalline stress corrosion. This article is intended to give an overview of the formation of NOx and the available methods to predict it, explaining the needs for its mitigation as well as providing certain directions to reduce its formation. CONSEQUENCES The reason why NOx is considered an undesired reaction product has two main reasons, first the environmental impacts. Secondly, and especially relevant for Hot Blast Systems, is the role NOx plays in the occurrence of Inter–Crystalline Stress Corrosion at the inside of the steel shell of the stoves. Environmental Impact The environmental effects of NOx have been a field of investigation for decades and are well documented [ref. 4]. One of the most important negative effects of NOx is the role it plays in

Dengler, Dr. Christian, Paul Wurth S.A., Luxembourg

Abstract: Automation is an essential component of modern plants. In addition to automation systems that operate the plant in hard real time, dedicated systems are used more and more to analyze important processes and suggest or even plan maintenance tasks with less and less human interaction. These systems perceive the current state of the plant and suggests actions based on sensor data combined with digitized knowledge, e.g., known process equations or the plant’s dimensions. Digitized knowledge is diverse and managing different forms of digital knowledge for complete plants is no simple task. The digital twin brings together all information available on the plant, from the engineering phase to simulations and operation data. Coupled with data analytics, a holistic tool for visualization and generation of recommendations supports the operators in their daily tasks. In this contribution, we present an overview of the developments and solutions by SMS-Group in relation to the digital twin and expert systems for the steel and iron making industry. The focus of the presented work lies on the digital solutions created using modern tools in order to generate value during operation.

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

Co-Author: John Tsalapatis, Ironmaking, Liberty Primary Steel • Matthew Middleton, Ironmaking, Liberty Primary Steel • Paul Zulli, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong

Abstract: Liberty Primary Steel’s Whyalla No. 2 Blast Furnace (W2BF) has operated for over 17 years since blow-in in 2004. The measured refractory temperature trends in the hearth show unique variations at different stages during this campaign, influenced by a variety of different refractory and operational conditions. From an operational perspective, an investigation was begun to more deeply understand the hearth and refractory condition throughout the whole W2BF current campaign. This included detailed investigations of the refractory, coke bed status and corresponding liquid flow behaviour in the hearth. In this study, a methodology was proposed to help explain the refractory temperature measurements (trend) based on simplified and comprehensive fluid flow and heat transfer modelling, measured refractory temperatures and other relevant operational data. Results of this comprehensive study show that the estimations of hearth refractory and hearth conditions determined from different sources are consistent over the course of the campaign. The predictions are verified through comparison between calculated and measured data, over the whole campaign life.

Dong, Dr. Xue Feng, 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.

Dorndorf, Dr. Markus, TENOVA LOI Thermprocess GmbH, Germany

Co-Author: Pablo Duarte, TENOVA HYL • Andre Esterhuizen, TENOVA South Africa Pty Ltd • Jorge Martinez, TENOVA HYL

Abstract: The move of steelmaking industry, as part of the decarbonisation of Europe’s economy by Carbon Direct Avoidance CDA, is towards natural gas-based (short-term) and hydrogen-based (long-term) iron reduction as substitute for carbon-based processes. But this path represents an extreme challenge, especially under the difficult economic conditions and the general global political situation. The key elements, the so called transition technologies, like the ENERGIRON-ZR® Direct Reduction Technology and melting technologies for iron making (SAF/OSBF) provide reliable tools to support each phase of this transformation process and represents the perfect interim solutions with highest flexibility and minimized negative economic impact. From an economic point of view, two approaches are particularly target-oriented and sustainable: • The combination of the ENERGIRON process with its flexible use of gaseous reducing agents (natural gas, CH4/CO/H2) and a smelting reduction furnace (SAF/OSBF) offers the possibility of continuing to use the existing steel route via the BOF to its full extent and replacing only the blast furnace (BF) in the process chain by direct reduction and smelting reduction. The liquid pig iron produced via the new process route has the same properties as conventionally produced pig iron, but with a significantly lower carbon foot-print, allowing the new technology concept to be seamlessly integrated into existing steel making facilities. • A centrally located plant of maximum size and the production of Cold DRI or HBI, with the unique flexibility for ~1% to 4,6% carbon, offers the possibility for several end users to use sus-tainably produced DRI/HBI to process it directly into steel in the EAF or FMF with other charg-ing materials such as scrap and liquid pig iron. The paper explains in detail innovative and forward-looking concepts for steel manufacturers and shows a way forward under the current difficult economic conditions and the tension between international competition and local environmental regulations, political conditions and costs.

Efetürk, Mohamed, Hüttenwerke Krupp Mannesmann GmbH, Germany

Co-Author: Andreas Janz, Hüttenwerke Krupp Mannesmann GmbH • Rosa Peter, Hüttenwerke Krupp Mannesmann GmbH • Marten Sprecher, Hüttenwerke Krupp Mannesmann GmbH

Abstract: The European steel industry has broadly committed to the European climate targets by developing decarbonisation plans. A common dominator of these plans is a transformation step, which includes a technology shift from carbon-based blast furnaces to green hydrogen-based direct reduction processes. This will happen around 2030, resulting in a significant CO2 reduction. Hüttenwerke Krupp Mannesmann GmbH (HKM) operates an integrated steel mill in Duisburg and generally agrees with the common decarbonisation plans. Despite these future action plans within the European steel industry, HKM already started to take action aiming for a significant CO2 reduction with the existing facilities before the transition point of 2030. Until this transition point, it is HKMs aim to make processes as CO2-efficient as possible. HKM has gained significant experience injecting natural gas (NG) into its blast furnaces through the tuyeres in the noughties. Regular injections were stopped as PCI became available in 2010. The re-establishment of NG-injection replacing pulverized coal (PC) will reduce the CO2 emissions of the blast furnace. Furthermore, as HKM operates no rolling mills, there is an excess of low-pressure, high hydrogen-containing (>70%) coke oven gas (COG), which is currently used for power generation. This article discusses how coke oven gas and other hydrogen-containing gases are utilized as additional reducing agents for the blast furnace and how it lowers the carbon footprint of HKM’s crude steel significantly.

Elliott, Richard, Hatch Ltd., Canada

Co-Author: Don Tu, Hatch Ltd. • Ian Cameron, Hatch Ltd.

Abstract: The total CO2e footprint of all ironmaking technologies is linked to their material and energy inputs. The CO2e costs embedded in the production of these feed materials are non-trivial, and complete accounting of these costs – from mine to metal – is necessary for a holistic comparison of the emissions footprint of the various ironmaking technologies. Thanks to an array of life cycle analyses reported in the literature, sufficient information is now available to perform this accounting. This work presents a collection of factors for the embedded CO2e cost of ironmaking feed materials and employs them in a comparative analysis of alternative ironmaking technologies based on available data. Results are presented and discussed in the context of Scope 1, 2 and 3 emissions. Of interest is the sensitivity of the total emissions of each technology to the reductant mix employed and the potential of each to mitigate global CO2e ironmaking emissions.

Elliott, Richard, 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.

Fleischanderl, Dr. Alexander , Primetals Technologies, Austria

Abstract: Steel is an invaluable material for many sectors. However, in the context of the climate crisis, the sector has come under increased scrutiny due to its reliance on carbon-intensive fossil fuels, primarily coal. Steel production accounts for around 9% of total global carbon emissions, and its hunger for coal continues to drive excavation. In recent years, governments across the world have been looking for ways to meet the goals of the 2015 Paris Climate Agreement, and as such, the political pressure on the sector to decarbonize is also mounting. But it is not only the governments putting the pressure on. Increasing financial pressures like the price of carbon and the rise in the popularity and credibility of Environmental, Social and Governance scores amongst a more environmentally conscious generation of investors looking to put their money where their morals are. According to several leading organizations the sectors transformation will see a phased approach. Short term, the existing integrated mills will implement major de-carbonization measures, reduce the specific fossil consumption, improve energy efficiency and implement a circular economy. In the mid-term fuel switching and electrification of processes will play a significant role. In this phase we might see two major trends, the implementation of EAFs into integrated mills (hybrid mills) with highest charge mix flexibility and new DR-based minimills. Since scrap supply will remain an undersupply alternative virgin feed from iron ore will remain important. Due to the availability limitation of high-grade iron ore, DR plants will have to utilize also lower grade ores, which has an impact on the steelmaking operation. Primetals Technologies is addressing this challenge and has been developing the hydrogen-based fine ore reduction HYFOR pilot project in Austria. What separates HYFOR from its green steel peers, is what

Geach, Paul , Primetals, United Kingdom

Co-Author: Martin P Smith, Primetals Technologies Austria GmbH

Abstract: The evolution of the Hot Blast Stove has been integral with the development of the blast furnace process for pig-iron production. As the steel industry adapts to deliver a reduced carbon footprint, the major technology changes in stoves and the operational improvement will be reviewed, with emphasis on the adoption of Top-Fired Stove technology. The paper will then assess different Top-Fired solutions, comparing the particular advantages and benefits of each, providing a critical summary of the available technologies.

Geerdes, Dr. Maarten, Geerdes Advies, Netherlands

Co-Author: Yongzhi Sha, Chinese Institute of Iron and Steel Industry

Abstract: There was about 1.28 billion tons of hot metal produced in 2019 with various operations of blast furnaces around the world. The present paper describes similarities and differences in BF operation based on hands on experience and operational results. The focus is on large blast furnaces (≥12 m hearth, ≥3200 m3 IV). The paper starts with comparing results in productivity, coke rate and total fuel rate. A comparison is made of: - The effect of BF size on operation results. - Raw materials being used, slag volume and composition as well as the effect of slag volume on PCI rates and productivity. - Operating philosophies: consistent versus variable blast volume. - Tuyere parameters like velocity and blast momentum. - PCI rates and oxygen enrichment. - Use of burden distribution.for optimizing BF operations. This includes the ferrous and coke layers that are being used as well as methods for using two sizes of sinter. In the discussion the authors address the question what operators can learn from each other. Note: this is the farewell lecture of Dr Maarten Geerdes, who leaves the BF community after turning 70 in March 2021

Geerdes, Dr. Maarten, 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.

Gols, Bert, 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.

Gordon, Dr. Yakov, 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.

Gordon, Dr. Yakov, Hatch, Canada

Co-Author: Mikhail Polovets, Ural Federal University • Vladislav Panteleev, Ural Federal University • Konstantin Mironov, NTMK-Evraz • Segei Zagainov, Ural Federal University

Abstract: Timely and complete taping of hot metal and slag is the main precondition of blast furnace intensive operation. Irregular taping leads to fluctuation of the level of liquid products in the furnace hearth, change in rate of material charging to the furnace and variations in a burden residence time in the furnace. Also it effects the thermal state of the furnace and chemical composition of the hot metal and slag. Ratio of tapped hot metal and slag is determined by physical properties of slag, diameter and length of hot metal taphole. Analysis of NTMK-Evraz blast furnaces operation showed significant fluctuations of this ratio. At average slag volume between 340-360 kg/thm the actual range of slag volume changes from 200 to 850 kg/thm. The fundamentals of mechanics of fluid and gases were applied to study the problem and laminate flow of hot metal and slag was assumed for the taphole. The ratio of the metal and slag mass in the taphole and hot metal and slag velocities were described as a function of slag parameters and taphole geometry. This approach allowed to derive numerical relationship between volumes of tapped hot metal and slag, slag viscosity and taphole design. Results of mathematical modeling were confirmed by actual performance parameters of NTMK-Evraz blast furnaces. It was found, that increase in slag to hot metal ratio led to the reduction in blast furnace productivity and reduction in vanadium partition to hot metal.

Gordon, Dr. Yakov, Hatch, Canada

Abstract: Gas dynamics and gas distribution in cross-section of shaft furnace play crucial role in increase of furnace productivity, reduction in natural gas rate and DRI quality improvement. Optimum design parameters of gas distribution devises were investigated by means of mathematical modelling, pilot plant and industrial installation studies. New heat transfer co-current schematics of gas and material movement with self-reforming of natural gas in metallization zone, was invented, patented and tested at pilot plant. New Shaft furnace design and improvements where proposed and some new gas distribution devises implemented for shaft furnaces, providing savings in fuel rate, increase in productivity and improvements in quality of DRI.

Gordon, Dr. Yakov, 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.

Guetta, Dr. Zion , thyssenkrupp Industrial Solutions AG, Germany

Abstract: The Gas Treatment Plants (GTP) of Acciaierie d'Italia has been just upgraded with new Claus plant, ramp up H2S/NH3 Desorption plant capacities and new chiller plant. The Arcerlormittal Gent (Belgium) has just started construction of new H2S/NH3 Desorption plant and new Claus plant. Both GTPs have a common goal, which is to reduce to low as possible the downtime of the desulfurization process by installing a 1+1 setups. This is state of the art of GTPs today. After the modification, Acciaierie d'Italia possess at least one standby unit in all plants of the GTP from Primary Gas Cooler (PGC) and up to Desulfurization. Acciaierie d'Italia has made itself completely weather independent and it is able to run on a hot south Italian summer a constant PGC outlet temperature. The GTP in Gent will continue to keep a clean COG even during boiler inspections or cleaning of internals owning to the new installation. The upgrading of an existing GTP (brown field installation) is counted to be one of the most difficult work in chemical engineering. That kind of work begins with a study to identify targets, concepts and last but not least budgets. At the pre-engineering phase, the tie-in points are investigated and identified by the engineers. The beigest challenge of engineering is to adapt a know process to the existing installation considering for example: flows, pressure and temperatures, accessibility, process control, local standards, modern standards, as well as minimize spare parts by trying to use the same wear parts as in the existing installation. The paper will present the arrangements of the GTPs and examples of engineers challenges, who developed solutions for some given specific difficulties with regard to brown field installations.

Günther, Peer Eric, TU Bergakademie Freiberg, Germany

Co-Author: Erik Oldinski, TU Bergakademie Freiberg / Institut für Eisen- und Stahltechnologie • Lukas Neubert, TU Bergakademie Freiberg / Institut für Eisen- und Stahltechnologie

Abstract: As part of the degree programme "Materials Science and Materials Technology" in the specialisation Steel Technology, a mini blast furnace was designed, built and operated by the students of the Institute for Iron and Steel Technology. The aim was to apply the basic knowledge of the blast furnace process from the lectures in practice. After the first hours of operation, the furnace was tapped for the first time and liquid pig iron and slag were obtained. The charge materials and products were analysed and the process evaluated. The results of the experiment showed that the blast furnace process can be demonstrated on a small scale with simple methods.

Hahn, Thomas, Beck u. Kaltheuner GmbH & Co. KG, Germany

Co-Author: Jan-Philipp Altgaßen, Beck u. Kaltheuner GmbH & Co.KG • Stephan Hermann, Beck u. Kaltheuner GmbH & Co.KG

Abstract: Drones are more and more involved in taking professional video footage of all kinds. Previous generations however had only a minor role in inspecting high temperature, dust loaded or dark facilities due to technical difficulties. In recent years improvements on lighting and camera systems have led to better visibility in dust loaded and dark rooms and newer Li-Ion technologies have led to longer flight duration. Flight stabilisation via route vectoring and internal sensors make it possible to have a smooth operation. With a cage housing drones are even possible to operate in small spaces without risk of colliding. This altogether widened the field of possible facilities to be inspected to e.g. cowpers, blast furnaces, and all sorts of second heat furnaces and flues and made drone inspections a reliable source for imaging with the option to have the data available even after years. Software aided analysis of the video footage can be completed with a full 3D Model and thus gives a good overview of the actual damage of the scene, or possible spots for preventive maintenance. With health and safety issues being a foremost important point in all companies worldwide, an operator that has not to undergo risks of going directly into the production facilities another point in favour to using drones is made. Also time consuming construction of scaffolding or the use of cranes is not necessary.

Hanel, Dr. Martina, 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.

Hanel, Dr. Martina, 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.

Hapugoda, Priyanthi, 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.

Heikkilä, Dr. Anne, 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.

Hohlweg, Frank, ArcelorMittal Bremen, Germany

Abstract: 123

Höntsch, Stephan, TU Bergakademie Freiberg, Germany

Co-Author: Andreas Siegfried Braeuer, TU Bergakademie Freiberg • Christopher Harris, voestalpine Stahl GmbH • Christoph Thaler, voestalpine Stahl GmbH • Laura Lohmeier, TU Bergakademie Freiberg • Ralf Wollenberg, TU Bergakademie Freiberg • Hans-Werner Schröder, TU Bergakademie Freiberg • Volker Herdegen, TU Bergakademie Freiberg

Abstract: Midrex process residues, such as screened oxide fines, hot briquetted iron (HBI) screened fines, dried sludge and process classifier dust contain iron and iron oxide that should be saved for better utilization of resources. The presentation is about basic research to achieve this by way of briquetting the residues with or without a binder for recycling in the reduction shaft furnace. After reduction the residue briquettes are converted into HBI by joint hot briquetting with the major proportion of direct reduced iron (DRI) pellets. Another way of utilizing the residues is adding them directly to the hot DRI pellets without prior reduction and integrating them finally also into the HBI. Process requirements for briquette production are described as well as quality parameters of the briquettes with special emphasis on mechanical strength, transport safety, thermal stability and reduction properties. REM and EDX analytical methods are used to get a deeper insight into the micro structure of the briquettes which helps understand the effect of process parameters on briquette quality. Finally, the results of a briquetting test with a roller briquetting machine in semi industrial scale gives prove of transferability of the results obtained in laboratory to industry.

Hu, Yichao, The University of Queensland, Australia

Co-Author: Mengran Li, Delft University of Technology • Tom Rufford, The University of Queensland • Geoff Wang, The University of Queensland • Liangyuan Hao, Hesteel Group Company

Abstract: As the most significant carbon consumer in the integrated steel mill, the blast furnace (BF) is expected to undertake the most considerable contribution to reduce CO2 emission and achieve a sustainable iron and steelmaking process. Currently, carbon capture and utilisation (CCU) to BFs is considered one of the hotspot technologies to sufficiently support the large CO2 emission reduction. A potential way is to capture CO2 from the ironmaking process and convert it into a reductant for the iron ores, feeding back to the blast furnace. This paper integrated the CO2 capture, electrochemical CO2 conversion and top gas recycling technology to improve the traditional blast furnace. Our work focuses on exploring different pathways of CCU, BF and hot blast stoves and evaluating their environmental performances through a two-stage mass and energy modelling with respect to minimise CO2 emission. With different integrated CCU ironmaking system pathways, the overall ironmaking process could save 80 kg/tHM of fresh coke or abate around 80% CO2 emission compared to that of the traditional ironmaking process. The electricity required of the current CCU system causes higher energy consumption than the traditional blast furnace. However, future progress in CO2 conversion technologies with high energy efficiency would improve the competitiveness of the integrated CCU ironmaking system. This work is expected to provide a guideline for allocating and using different CO2 emission sources to achieve a carbon-neutral blast furnace ironmaking process.

Janakova, Nella, Progres Ekotech, s.r.o., Czech Republic

Co-Author: Nella Janakova, Progres Ekotech, s.r.o.

Abstract: The paper presents a cold technology to produce a low-carbon BF feedstock which is used to supplement the sintering process of iron ore as it is currently known. The implementation of this production process of BF feedstock causes lower energy consumption compared to the high-temperature process of sintering. The result is quite a reduction of energy and significantly lower carbon footprint. A key factor in reducing the carbon footprint is the cold production process, as there are no direct CO2 emissions. In addition, the technology contributes to lower consumption of iron ore and coke and to efficient re-utilization of by-products from metallurgical processes like scale and fractions of dust and slag. The BF burden produced by The EcolBriq® process shows mechanical product characteristics, very favorable mechanical and physical properties, such as: high strength 6-12 MP, which makes it easily ready as BF charge. An additional benefit of EcolBriq® is the possibility of year-round outdoor storage without changing the briquette properties. A single production line with a capacity of 400KT / year can be utilized for a wide variety of materials with different structures, eg: powder, oxide, metal with sizes 0-200 mm. In contrast with sinter the briquette´s shape and size can be adjusted within a wide range to optimize the BF operation. This flexibility offers the possibility of creating an optimal low-carbon charge tailored to optimum blast furnace operation and quality of the hot metal. The presentation will show the advantages by two case studies, which quantify the results arising from: i. Reduction of CO2 emissions for production of the EcolBriq® feedstock compared to sinter ii. Reducing the consumption of natural resources for EcolBriq® iii. Dust reduction for EcolBriq® compared to sinter plant iv. Maximizing the efficiency of the circular economy in BF operations v. Reducing energy intensity

Kamijo, Dr. Chikashi, Nippon Steel Corporation, Japan

Co-Author: Shin Tomisaki, Nippon Steel Engineering Co., Ltd. • Yutaka Ujisawa, Nippon Steel Corporation • Koki Nishioka, Nippon Steel Corporation • Kaoru Nakano, Nippon Steel Corporation • Hiroshi Sakai, Nippon Steel Corporation • Kazumoto Kakiuchi, Nippon Steel Corporation • Kohei Sunahara, Nippon Steel Corporation • Hirokazu Yokoyama, Nippon Steel Corporation • Yoshinori Matsukura, Nippon Steel Corporation

Abstract: COURSE50, CO2 Ultimate Reduction System by Innovative technology for cool Earth 50, is the national project for reduction of CO2 emission from steelworks in Japan. Three steel companies, NIPPON STEEL CORP., JFE Steel Corp., and Kobe Steel Ltd, and one engineering company named NIPPON STELL ENGINEERING CO., Ltd. join this project supported by NEDO (New Energy and industrial technology Development Organization). The target of COURSE50 is reduction of CO2 emission from steel works by 30 %, 20 % by CCS and 10 % by operation of blast furnace. In order to realize the CO2 emission form blast furnace by 10 %, H2 utilization technology has been developing using 12 m3 experimental blast furnace. The experiments have been taking place form 2016. From 2016 to 2017, 10 % reduction of CO2 emission achieved by using three methods, gaseous reductant injection from tuyeres, gaseous reductant injection from shaft tuyeres, and high reducibility sinter ore charging. In order to improve the reduction CO2 emission technology, hydrogen-based gaseous reductants and high reducibility sinter were used form 2018. Two campaigns, 32 days each, were taken placed in 2018 and 2019. Three types of H2 concentrate gaseous reductants were injected. As a result, it is clarified that the reduction ratio of CO2 emission was affected by the H2 concentration. Over 10 % of CO2 emission was reduced with highest H2 concentration gaseous reductant injection.

Kim, Dr. Dong-Geun, 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.

Kuskov, Volodymyr, 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.

Lin, Dr. Rongshan, 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.

Lin, Dr. Rongshan, AG der Dillinger Huettenwerke, Germany

Co-Author: Andreas Feiterna, AG der Dillinger Huettenwerke • Alexander Babich, RWTH Aachen University • Jean-Paul Simoes, RWTH Aachen University • Dieter Senk, RWTH Aachen University

Abstract: Reduction of CO2 emission is an important challenge for integrated steel plants. Injection of hydrogen rich gas into the blast furnace is one of the most suitable and ready accessible measures to substitute carbon input and consequently to reduce the overall CO2 emission. For almost 3 years, started in November 2017 at ROGESA (Roheisengesellschaft Saar mbH) coke oven gas (COG) was injected at pilot scale and, since June, 2020 at industrial scale into No. 4 and No. 5 blast furnace. The pilot project has been launched to investigate and gain valuable experience on different aspects. First, the pilot installation was configured to be able to inject coke oven gas through the copper tuyere at high flow rates in order to reduce the overall carbon-dioxide emissions. Secondly, the pilot installation was adapted to enable adding simultaneously minimal required quantities to the transport gas of the pulverized coal in order to improve the ignition and conversion of the coal at the tip of the oxy-coal-lance. Thus, the pilot installation delivered us to gain valuable information for the industrial up-scaling on different injection technologies, on the handling H2-rich gas from safety aspect and the behavior of H2 as ignition gas to improve the gasification-conversion of the coal. In parallel, laboratory trials under blast furnace simulating conditions have been performed at the RWTH Aachen University in order to testify the effect of adding coke oven gas to the transport gas of the pulverized coal. Based on these investigations, an industrial plant has been built and commissioned. This paper presents the results obtained at the laboratory trials at the RWTH Aachen University, at pilot installation in Dillingen and the first industrial results obtained on No. 5 blast furnaces of ROGESA.

Lomas, Dr. Hannah, 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.

Long, Edward, 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.

Long, Edward, Primetals Technologies, United Kingdom

Co-Author: Colin Morrison, Primetals Technologies • Jeremy Fletcher, Primetals Technologies • Mark Geach, Primetals Technologies

Abstract: Consistently high hot blast temperature and the resultant lower fuel rate and CO2 emissions are important financial drivers for all blast furnace operators – Primetals Technologies’ solutions and development fully support these targets. As the steelmaking world tries to assess how to reduce CO2, and which future technologies to back, determining the benefits of spending capital on an existing blast furnace can be difficult. Spending capital on ancillary equipment such as the hot blast stove system can be a major part of this assessment. This paper will assess some of the technical solutions currently available as well as possible future technologies, particularly comparing the traditional internal combustion chamber and the top fired stoves solutions. The paper will assess CAPEX against OPEX reduction over various timescales, and the Return on Investment (ROI) possibilities.

Lundgren, Dr. Maria, 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.

Lüngen, Dr. Hans Bodo, on behalf of Steel Institute VDEh, Germany

Abstract: Blast furnaces need coke for iron ore reduction and melting of the ores to liquid hot metal whilst separating a part of the gangue components of the blast furnace charge materials via a liquid slag from the hot metal. Coke was always rated as the necessary evil of the blast furnace especially in those years, when cokemaking facilities had problems in environmental protechtion. Direct reduction of iron ores is done in the solid stage without the need of coke. Just the main content of the oxygen is removed from the iron ores without melting and without slag metallurgy. This means, that all the gangue materials remain in the product sponge iron, called Direct Reduced Iron (DRI). Direct reduction processes can be classified by its kind of used reducing agent in gas-based processes and coal-based processes. Gas-based processes are shaft furnaces, retorts and fluidized beds. Coal-based processes are rotary kilns, rotary hearths and the multiple heath. The advocates of the direct reduction technologies have forecast a quick penetration of these processes from the 1970ies on and a replacement of blast furnaces with especially the gas-based reduction processes. This never occurred. The worldwide production of DRI was 114 mil. t in 2021 whist the hot metal production of blast furnaces 1340 mill. t. The gas-based direct reduction processes have a share of 75 % at total DR production and this is mainly done in regions with cheap natural gas prices. The main processes are the Midrex and the HyL/Energiron shaft furnace technologies. These have been developed to high level and most efficient processes with an industrial scale-up to 2.5 mill. t DRI production per year in a single module. In Europe a Midrex DR plant was built a very early stage as the second industrial unit worldwide in 1971 in Hamburg, Germany, with a capacity of 400.000 t DRI/year. With respect to the high gas prices in Europe and the steady increase of blast furnaces size and efficiency it was the only DR installation by now. Due to its use of natural gas as reductant the DR-EAF route has lower CO2 emissions compared to the blast furnace converter route. On the background of the current European target to become a climate neutral region by 2050 the DR technology based on natural gas and hydrogen used in DR shaft furnaces for DRI production currently gain huge importance.

Lüngen, Dr. Hans Bodo, on behalf of Steel Institute VDEh, Germany

Co-Author: Peter Schmöle, Schmöle Consulting

Abstract: The integrated steel works in Western Europe operate modern plants to produce a wide variety of high-grade steel products. Currently, the blast furnace-basic oxygen furnace (BF-BOF) route for steel production is the main production route within Europe with a share of 57.3 % at total crude steel production in 2021. The other 42.7 % is produced by scrap-based Electric arc furnaces. The integrated BF-BOF-route is today operated close to its theoretical minimum in carbon consumption, but it is still the main CO2 emitter in iron and steelmaking. This needs to be changed, because the requirements of the society to stop the climate change and to limit temperature increase to 2° C by the year 2050 compared to the pre-industrial decades of the late 19th century require massive efforts for the steel industry to reach the target of CO2-free steel production. The key ways to reduce CO2 emissions in iron and steelmaking can be summarized under the general terms “Smart Carbon Usage” (SCU) and “Carbon Direct Avoidance” (CDA). SCU covers on the basis of carbon carriers as reductant incremental measures at the conventional blast furnace converter route and the CO2 mitigation measures by applying so-called “end-of-pipe” technologies like CCS (CO2 Capture and Storage) and CCU (Carbon Capture and Usage). CDA covers the scrap based electric arc furnace route and the iron ore based steelmaking route via direct reduction plants and electric arc furnaces by the use of natural gas and/or hydrogen as reducing agent, which means the complete avoidance of coal and coke for the reduction of iron ores. The application of CCU at the conventional blast furnace converter route, which means the conversion of process gases into chemical raw materials, as well as the implementation of the direct reduction technology with hydrogen and subsequent smelting of the DRI (Direct Reduced Iron) to steel in an electric arc furnace or a combination of a submerged arc furnace and a basic oxygen steel converter require an immense amount of hydrogen and CO2-free electric energy. The transformation of the integrated BF-BOF route to DR-EAF route requires huge amount of capex and higher rates of opex.

Lüngen, Dr. Hans Bodo, on behalf of Steel Institute VDEh, Germany

Abstract: Opening of the conference by the chairman

M. de Carvalho, Dr. Rodrigo, 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).

Maruoka, Dr. Daisuke, 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.

Mattila, Olli, 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.

Meisch, Claude, TMT, Luxembourg

Co-Author: Richard Geyer, AG der Dillinger Hüttenwerke • Jürgen Hochhaus, AG der Dillinger Hüttenwerke • Volker Langer, TMT

Abstract: An efficient blast furnace production process requires, amongst other things, a smooth cast house operation. The reliability of cast house equipment is also crucial for operational safety. It is therefore highly recommended to monitor the condition of the tapping equipment using the transmitters installed. A rudimentary equipment condition monitoring system is often part of the tapping equipment PLC software. However, when it comes to tapping process quality monitoring and predictive maintenance, PLC is not the right tool to get on. To fully exploit the potential of data-driven monitoring, TMT developed TapMan™, the tapping equipment condition monitoring and process control software that covers both operational and maintenance requirements. Automatic data analysis, based on both human experience and artificial intelligence, is a key feature of this tapping expert system. TapMan™ takes into account e.g. operator information on used consumables and main component replacement and indicates optimisation potential of the tapping process. This facilitates the benchmarking of tapping equipment and component lifetime amongst different furnaces. Operators can so benefit from each other’s experience, to reduce the operational costs and to optimise their spare parts management. Tapping process and equipment operation transparency is provided, including remote assistance if required. This Industry 4.0 application is continuously further developed by TMT and can be customised by clients according to their specific needs. TapMan™ is in operation at the Dillinger Blast Furnace 5 since 2020.

Mersch, Olivier , Paul Wurth S.A., Luxembourg

Co-Author: Christian Dengler, Paul Wurth S.A. • Fabrice Hansen, Paul Wurth S.A. • Marc Schweitzer, Paul Wurth S.A.

Abstract: Driven by the growing pressure to maximize production efficiency, the digital transformation has gained momentum within the industrial sector. Data-driven solutions will take over a crucial part in future production and increasingly improve processes across the entire life cycle of plants. The following contribution puts maintenance of one of the core technology in today’s blast furnace iron making in the light of the digital age: the Paul Wurth Bell Less Top® charging system. With the overall objective to ensure a long service life, optimum performance and reliable operation, the Bell Less Top needs to be continuously monitored. During operation, the system may output phenomena that are not easy to detect using a programmable logic controller. Key for a reliable monitoring is lying in the detection of short-, medium- and long-term trends, the recognition of recurrent events, the comparison of current states with historical baselines and particularly the recognition of dependencies between several phenomena. Reliable monitoring allows to efficiently implement maintenance processes in order to optimize the use of resources and reduce downtime. Maintenance can be scheduled on real condition and advanced statistics rather than on preventive actions. This contribution gives insights on how BLTXpert™, a condition and performance monitoring system for the Paul Wurth Bell Less Top, provides significant added value to the operator as well as maintenance staff and paves the way from fail and fix to prevent and predict.

Merten, Henry, Ruhr-Universität Bochum, Germany

Co-Author: Siegmar Wirtz, Lehrstuhl für Energieanlagen und Energieprozesstechnik, Ruhr-Universität Bochum • Stephan Hojda, AG der Dillinger Hüttenwerke, Research & Development Iron and Coke Making • Rongshan Lin, AG der Dillinger Hüttenwerke, Research & Development Iron and Coke Making • Viktor Scherer, Lehrstuhl für Energieanlagen und Energieprozesstechnik, Ruhr-Universität Bochum

Abstract: The lifetime of an industrial blast furnace is strongly affected by the campaign length of the hearth lining. Therefore, understanding the processes related to lining degradation in the hearth is essential. Since on-site measurements and experimental approaches can only provide a limited insight, numerical simulations are a valuable tool to evaluate the complex multiphase flow involved. The current work presents a numerical DEM-CFD simulation study of the multiphase processes in the blast furnace hearth. The movement of a particulate phase (coke particles), three continuous fluid phases (hot metal, liquid slag, gas) and their interactions are computed by a combined Eulerian-Lagrangian approach. In the BF hearth movement of the coke bed and the hot metal flow are intimately connected. Therefore, a coupled DEM-CFD approach is necessary to account for the transient movement of the coke particles instead of conventionally assuming a predefined porosity field. As the calculation of actual size particles in the total hearth is not feasible due to extensive computational cost, a static porosity field is assumed except for the region in front of the taphole. This results in two different domains for the CFD-side (total hearth) and the DEM-simulation (close-up of a coke bed section). Since steep velocity gradients and a high carbon dissolution rate prevail in this specific region, the movement of solid particles is of main interest. In particular, the principal flow direction of particles filling up the void space of dissolved coke is investigated. Since the path line of a single particle is determined by the interaction with the fluids (buoyancy and drag forces) and the mechanical interaction of solids, the numerical approach contributes a valuable insight into BF hearth phenomena, which are otherwise inaccessible.

Mežibrický, Dr. Roland, 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.

Mousa, Dr. Elsayed, Swerim, Sweden

Co-Author: , • Hesham Ahmed, Luleå University of Technology • Mohamed El-Sadek, Central Metallurgical Research and Development Institute

Abstract: The recycling of iron rich residues created by the different steel works has turn into an urgent issue due to ores depletion and strict environmental regulations. Mill scale is one of the iron rich residues generated during steelmaking, casting, and rolling processes. It is too fine to be charged directly to the iron and steel making units without pre-agglomeration. This paper demonstrates the feasibility of briquetting of the mill scale using organic binders to meet the requirements of hydrogen-based direct reduction. The influence of binder type, binder dosage, moisture content, compaction pressure on the briquetting process and the briquettes quality will be investigated. The briquettes quality will be characterized for their mechanical strength and reduction behaviour. The mechanical strength is measured by using a compressive tester machine and the reduction behviour is studied by thermogravimetric analysis (TGA).

Muscolino, Fabio , 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

Nanz, Thomas, 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.

Nogami, Prof. Hiroshi, Tohoku University, Japan

Co-Author: Shinsuke Taya, Tohoku University • Seiya Ueda, Tohoku University • Shungo Natsui, Tohoku University

Abstract: In ironmaking blast furnace, the raceway zone is one of the most important regions, since it strongly relates to the efficiency and the stability of the blast furnace process. Thus, the understanding the characteristics of the raceway zone is quite important in designing and operation of blast furnace operation. In this study, formation behavior of raceway in cold model was numerically analyzed and was discussed. A mathematical model of particle and fluid dynamic behavior was developed. The model tracked particle behavior by using the discrete element method and solved fluid flow field by using traditional computational fluid dynamic technique. These methods were combined through the distribution of void fraction and the flow resistance in the packed bed. The model was applied to some conditions in cold model experiments, and the raceway behaviors were successfully reproduced. The cold blast extruded the particles just in front of the tuyere and formed a cavity. Then the particle circulation was induced. The model also successfully revealed the transient variations of gas flow pattern, pressure distribution and inter-particle contact force network as well as the particle motion. Under the fixed bed condition, the formation behavior and the final size of the raceway were strongly affected by the initial packing condition. Contrarily, the size and the flow behavior of the formed raceway were almost independent of the initial packing. Additionally, the particles were numerically tracked, and the motion and the force balance were analyzed along the particle trajectories.

Penz, Dr. Florian Markus , Primetals Technologies, Austria

Co-Author: Hans Joerg Baumgartner, Primetals Technologies

Abstract: As the whole steelmaking world is at the edge of transformation to decarbonized production, iron ore pellets will play a central role as a high-quality iron bearing feed. Therefore, not only productivity but mainly requirements on pellet properties will rise to the possibly highest level to serve for high quality and low carbon production in downstream iron and steelmaking. Primetals Technologies pelletizing simulation tool was developed to calculate with a complex and highly flexible numerical model all important process data of any type of induration machine (e.g. travelling grate and grate kiln). Gas and solid flows of the pellet layers are calculated by solving 150 differential equations in each cell. Implemented parameters are fully validated through experimental results at Primetals Technologies pellet pot or at customers’ production facilities. Therefore, this tool can be used both for design of new pellet plants as well as for optimization of the entire induration process of existing pelletizing plants under consideration of productivity, product quality, energy consumption and environmental aspects at the same time. For the first time, such sophisticated numerical model can be integrated in an advanced Level 2 expert system as support of daily operation to enable early reaction on changing conditions such as e.g. changing raw material qualities. The paper will give an insight into Primetals Technologies simulation tool, its features, capabilities and different applications.

Perret, Fabian, 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.

Perret, Fabian, 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.

Radloff, Rainer, RWTH Aachen University, Germany

Co-Author: Ali Abdelshafy, Wissenschaftlicher Mitarbeiter • Grit Walther, Chair of Operations Management - RWTH Aachen University

Abstract: Hydrogen-based direct reduction is a promising route to decarbonize the production process of primary steel. Nonetheless, as its value chain is significantly different than the conventional technology (i.e. blast furnace), the transformation of steel industry towards hydrogen will be associated with crucial changes. Hence, this study presents a case study from Western Germany via quantifying the changes in the regional material and energy flows in the state of North Rhine-Westphalia. The quantitative analysis firstly presents a detailed material and energy flow model that depicts the existing supply chain of the regional industry and intersectoral relations. Thereafter, the derived process model of the hydrogen-based steel is integrated into the initial models in order to track the changes associated with the regional roadmaps for reaching zero-carbon steel. The analyses show that these structural changes will require more than 47 TWh renewable electricity per year. As this figure represents approximately one tenth of the current German power production, there are doubts that the renewable resources can satisfy this significant demand, especially if the sectors are taken into account. Therefore, more resilient strategies are needed in order to make sure that decarbonization plans can be achieved even with lower volumes of renewable electricity. For example, deploying natural gas as a reductant along with other technologies such as carbon capture and storage can significantly decrease the demand for electricity. Moreover, as hydrogen and natural gas use the same facilities, such approach can also help in upscaling the required infrastructure in the future. Keywords: primary steel; direct reduction; green hydrogen; energy and material flow model; process model; renewable electricity; natural gas

Rassel, Georges, Paul Wurth & CEO Region Europe SMS group, Luxembourg

Abstract: Exploring Paul Wurth's latest technological developments: How are we in SMS group building on our metallurgical expertise to advance green iron & steelmaking?

Redenius, Dr. Alexander, 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.

Sadri, Dr. Afshin, 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.

Sasiain, Amaia, 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

Sathler, Filipe, ArcelorMittal Tubarão, Brazil

Co-Author: Franklin Alexandre da Silva, ArcelorMittal Brazil • Renato Sarmento da Costa, ArcelorMittal Brazil • Filipe Sathler, ArcelorMittal Brazil • Leonardo Passos Perdigão, ArcelorMittal Brazil • Estefan Campos Ribeiro, ArcelorMittal Brazil • Claudio Cesar da Costa, ArcelorMittal Brazil • Frederico Godinho Cunha, ArcelorMittal Brazil

Abstract: This work describes the history and improvements of the second campaign of ArcelorMittal Tubarão Blast Furnace #3 that began on July 2014. There was a blowdown in April 2020 due to crisis period but returned to operate in October 2020 (same campaign without hearth repair). With Inner Volume of 3617 m³, 4 tap holes, 12,5m of hearth diameter and 34 tuyeres, blast furnace process and equipment were improved in several steps. After blow in on 2014, high pulverized coal injection project has started, decreasing total coke rate from 350 kg/t in 2014 to below than 290 kg/t. During the coke rate evolution, many challenges were faced to sustain blast furnace stability, for example: hearth temperature control, raw material quality worsening, jumbo cooling damage, equipment availability, blowdown with salamander tapping and blow in with remaining salamander. To overcome those challenges, developments such as burden distribution improvements, burden segregation tests, process control, integrated management and raw materials quality adjustments. This paper presents highlights of main events and developments of blast furnace #3 second campaign.

Sathler, Filipe, ArcelorMittal Tubarão, Brazil

Co-Author: Ramiro Da Conceição Do Nascimento Junior, IFES (Instituto Federal Do Espírito Do Santo)

Abstract: With steel market development and steel production advance, there is a historical quality degradation of iron ores which are used for sinter production and for pig iron production at blast furnace. On the other hand, amid this scenario of mineral resources restrictions and raw materials worsening, blast furnace aims to achieve high productivity and high pulverized coal injection rates (PCR) in order to decrease operational costs. However, to sustain such results, it is necessary to ensure slag volume reduction on blast furnace lowering harmful elements input and to assure raw materials properties optimization (physical, chemical and metallurgical). Aligned with those perspectives, this work presents the discussion of industrial data obtained from an integrated steel plant in order to: evidence effects of granulometry and chemical quality of the iron ore mixture (sinter-feed) into the sintering process (permeability, density control, productivity, fuel consumption, burnt lime injection); correlate consequences of sinter chemical quality adjustments into sintering process; and, demonstrate the influence of sinter quality modifications (physical, chemical and metallurgical) into blast furnace operational performance (permeability, slag index, top gas efficiency, productivity, fuel consumption). Therefore, the improvements and discussions carried out throughout this work have allowed to mitigate effects of iron ore quality worsening into sintering process, sinter quality and blast furnace performance.

Saxen, Prof. Henrik, Abo Akademi University, Finland

Co-Author: Debanga Nandan Mondal, Abo Akademi University • Olli Mattila, SSAB Europe Raahe • Timo Paananen, SSAB Europe Raahe • Yalcin Kaymak, VDEh Betriebsforschungsinstitut • Hauke Bartusch, VDEh Betriebsforschungsinstitut • Weiqiang Liu, Abo Akademi University

Abstract: The gas distribution plays an important role for the blast furnace process as it affects the thermal and chemical conditions in the shaft, and also the pressure drop and burden descent. The distribution of the gas is usually indirectly evaluated based on temperature and composition measurements at several points over a radius or diagonal by above-burden or in-burden probes. Novel acoustic techniques can estimate the gas temperature over the full cross section of the throat. However, an inherent problem is that the gas is redistributed in the upper bed and particularly above it, so measurements above the stockline may no longer reflect the conditions in the shaft. The paper studies the fate of the gas in the region between the stockline and gas uptakes by a CFD model. Heat transfer is neglected so the study is focused on the redistribution of the gas and its effect on the temperature. It is shown that a strong redistribution and downward-swirling flows may occur, creating non-intuitive gas flow patterns in certain parts of the throat region. The role of burden layers charged at different points is also analyzed, giving rise to different flow patterns above the bed. A brief study of the dynamics of the changes is also undertaken. Finally, the findings are compared with measurements based on acoustic techniques, demonstrating similarities in the patterns. The results of the study highlight the complex flow patterns that can be encountered in the top region of the blast furnace, and can partly explain anomality seen in the measured temperature patterns.

Saxen, Prof. Henrik, Abo Akademi University, Finland

Co-Author: Jan van der Stel, Tata Steel Europe • Gerard Louwerse, Tata Steel Europe

Abstract: The life length of the blast furnace is usually determined by the wear of the hearth refractory, so it is important to estimate the extent of the hearth wear during the campaign. Since it is impossible to directly measure the thickness of the remaining refractories, approaches based on inverse heat transfer formulations have been proposed. These one- or two-dimensional models of the system estimate how the position of the inner hearth profile progresses throughout the campaign by solving a sequence of static states based on temperatures measured by thermocouples in the lining. By this procedure it is also possible to track the formation of skull on the hot face. Crucial parts for the hearth wear are the regions close to the taphole, where the liquid flow is strongest. However, the thermal conditions in these regions make the use of one- or two-dimensional models incorrect since the taphole, when operated, acts as an additional heat source and further induces strong short-term dynamics that should not be neglected. The paper proposes an inverse heat transfer model that appropriately considers the heat source of the liquids in the taphole and the dynamics caused by the intermittent tapping operation. The model focuses on the region around the taphole and estimates the position of the hot face, i.e., the inner end of the “mushroom” formed by the taphole mud, based on the time evolution of the temperatures of the closest thermocouples in the lining. The paper describes the basic assumptions and equations of the model and presents an application of it to measurements from a large blast furnace. The estimates of the local wall-mushroom thicknesses on the different sides of the taphole are found to be correlated and also to follow the changes in the taphole length, which indicates the feasibility of the approach.

Schaub, Eric, 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.

Schulten, Marc, 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.

Shepetovsky, Dr. Igor, 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.

Smaha, Bartosz, 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.

Small, Dr. James, 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.

Sormann, Dr. Axel , 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

Specht, Michael, 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.

Steinparzer, Dr. Thomas, 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.

Streiff, Damien, Zentralkokerei Saar GmbH, Germany

Abstract: 123123

Tahmasebi, Dr. Arash, 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.

Tahmasebi, Dr. Arash, The University of Newcastle, Australia

Co-Author: Arash Tahmasebi, The University of Newcastle • Brody Brooks, The University of Newcastle • Kim Hockings, BHP

Abstract: The plastic layer permeability was investigated by using an integrated permeability/dilatation measurement rig and an in-situ permeability rig. The integrated measurement rig enabled the synchronized measurements of permeability and dilatation of coal samples during heating. The in-situ permeability measurement was fitted in the 4kg lab-scale double heated wall coke oven to measure the plastic layer permeability under thermal gradient induced coking conditions. To interpret the measurement data, the microstructure transitions across the plastic layer samples obtained from the plastic layer sampling technique fitted in the 4kg coke oven were analyzed by Synchrotron micro-CT. The permeability results and pore structure parameters derived from those analyses were correlated to better understand the mechanism of plastic layer permeability. Among all samples tested, the high-rank coking coal with low fluidity showed the lowest permeable peak at the later thermoplastic stage, corresponding to the high internal gas pressure (IGP). The microstructure in the resolidified layer of the high-rank coal was characterized by the lowest number of isolated pores and the larger volume of open pores within a larger size range of 50-100 µm, compared to those of the lower rank coals. In addition, its pore wall structure was highly compacted due to the high IGP. Based on these observations, a likely explanation of the lowest permeability of the high-rank coal is that the lower deformability of the pore wall structure at the later thermoplastic stage may have prevented additional pore growth, which prevented pore interconnectivity and decreasing permeability. For the high-pressure coal, there was a slight decrease in porosity in the initial softening layer. It is possible that the formation of the low permeable barrier redirected the plastic mass toward the loose coal side, thus increasing the fluidity of the region and filling the interparticle voids. These results suggest that the plastic layer permeability

Van der Stricht, Dr. Wim, ArcelorMittal, Belgium

Co-Author: Tobias Plattner, Primetal Technologies • Prabhakar NAIR, LanzaTech • Alexander Fleischanderl, Primetal Technologies

Abstract: Technological solutions, to utilize process gases from the iron and steel industry for production of fuels and chemicals, are an attractive sustainable and economic approach for industries today. This innovative approach converts carbon and hydrogen-rich off-gases, such as coke oven gas, blast furnace top gas and also converter gas into liquid based energy sources through a biological gas fermentation process to produce preferably ethanol or other chemicals. To produce ethanol, an integrated fermentation system with additional downstream installations is required to treat the fermentation product and waste streams. The treatment of the fermentation waste streams results in a number of by-products, usable for internal or external applications. By returning the by-products to an integrated steel plant or recovering the inherent energy, the fermentation system can be operated in circular system, with minimal waste. The first European commercial scale application of this technology is being developed at the ArcelorMittal steel plant in Ghent with the objective of producing 80 million liters of ethanol per year to be used as renewable transport fuel in a first stage, and as chemical building block on the longer term. We will present the latest developments in the construction of the plant and potential GHG reductions in the steel sector.

van Laar, Reinoud, 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.

van Laar, Reinoud, Danieli Corus BV, Netherlands

Abstract: -abstract

van Opbergen, Rob, 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.

Vieira Junior, Eustáquio, 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.

Vitikka, Olli, University of Oulu, Finland

Co-Author: Andrey Malkki, Kivisampo Oy • Illia Tkalenko, AMCOM GROUP LLC • Nikita Koriuchev, AMCOM GROUP LLC • Timo Fabritius, University of Oulu • Anne Hietava, University of Oulu • Mikko Iljana, University of Oulu

Abstract: One way to improve the recycling of by-products from iron and steel production is briquetting, a process in which fine materials unsuitable for use as such are agglomerated to achieve a larger particle size. This work is about the high-temperature properties of auger pressing briquettes mainly consisting of blast furnace sludge and mill scale. The aim was to determine the suitability of the briquettes for blast furnace (BF) ironmaking by studying the reduction, swelling and cracking behavior using blast furnace simulator (BFS) furnace. The BFS, able to perform non-isothermal reduction experiments with changing gas atmospheres, was used to simulate the reducing conditions in a BF. In the BFS experiments, different stages of reduction up to 1100 °C were simulated for the auger pressing briquettes. A commercial olivine pellet and a differently agglomerated industrial blast furnace briquette were used as reference samples. The sample weight losses were monitored by thermogravimetry, swelling as a change in the external dimensions, and cracking by visual inspection. TG-MS analysis was carried out to determine the presence of potentially harmful volatiles. The samples were analyzed using LOM and FESEM to study the phase transformations. The auger pressing briquettes proved to be a promising raw material for BF use. They were of self-reducing type due to their carbon content, and they were reduced to metallic iron faster compared to the reference briquettes. The swelling was slight, and despite minor cracking the auger pressing briquettes did not degrade. No harmful volatile substances were found but their existence cannot be completely ruled out.

Warren, Peter, British Steel Ltd, United Kingdom

Co-Author: Maarten Geerdes, Geerdes Advies • Jacob Tyszka, British Steel

Abstract: The blast furnace process is very variable, which is -among other things- manifest from large variability its thermal state: hot metal temperature and silicon content. So, at every operating blast furnace the thermal level is continuously controlled. However, when comparing blast furnace thermal control methods in various plants, there are large differences. Thermal control is analyzed from the perspective of the “melting capacity” of the bosh gas, that is the amount of heat available to melt the ferrous burden and slag in the lower part of the blast furnace. Since the major part of the heat requirement is used for driving direct reduction reactions and hydrogen is an efficient reducer at high temperature, the role of hydrogen in thermal control is discussed as well. A theoretical analysis is made to calculate the additional melting capacity that would be generated when coal rate is increased with and without an increase in oxygen enrichment to maintain flame temperature. This is applied to a real example of actions taken to prevent a blast furnace from severe cooling, and why these actions work, and to possible actions to take when coal rate is reduced due to supply problems whilst oxygen enrichment is maintained. Finally the importance of maintaining a minimum blast kinetic energy is discussed, along with the improvement made when tuyeres are clayed to maintain a minimum kinetic energy at low productivity.

Weichbold, Dr. Christian, 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.

Weiss, Dr. Bernd, Primetals Technologies GmbH, Austria

Co-Author: Johannes Niel, TU Wien • Walter Wukovits, TU Wien • Stefan Tjaden, K1Met • Bernhard Rummer, Voestalpine Stahl Linz

Abstract: Iron and steel making requires a wide range of different raw materials significantly influencing process performance which demands a continuous optimisation of process routes also with respect to energy efficiency as well as environmental emissions. Steadily changing raw material prices and qualities, market situations and product variations are challenging integrated steel plant operators in production planning and cost optimization. Primetals decided to develop a comprehensive metallurgical flow sheet model library for simulation and optimization of integrated steel plants. Intensive development efforts were taken in order to migrate existing well-established calculation and engineering routines as well as integrate newly developed models. The generated model library enables the setup of mass and energy balances for integrated steel plants, development and evaluation of new process concepts as well as investigations on impacts of raw material changes and trace material distributions. Recently coking plant operation data of an European coke producer was evaluated and based on a wide literature study predictive models for CRI, CSR, I10 and I40 developed. In a new approach the models were incorporated in a global mathematical optimization routine for strategic operations planning of integrated steel plants. Insight will be given on the models for prediction of coke parameters and its influence of overall operation optimization.

Wilhelmi, Dr. Arndt, 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.

Willemsen, Richard, Danieli Corus, Netherlands

Co-Author: Alain Woltheus, Danieli Corus • Magnus Sarbrant, Danieli Corus • Peter Öberg, SSAB Europe

Abstract: As a part of the modernization of the Oxelösund Blast Furnace No. 4 hot blast system, SSAB and Danieli Corus built an additional hot blast stove in 2019, for commissioning in 2020. After careful preparation, the vessel shell was fully prefabricated in an off-site workshop and erected in its operating position in a single lift. This resulted in a much swifter and safer execution of both the on-site and off-site activities connected to the construction phase since the majority of the welding, coating and inspections could take place in the workshop - which is a working environment fully optimized for such activities - minimizing on-site work under plant regulations and more difficult circumstances. In addition to the construction method, the improved burner design is a key feature of this hot blast stove. With comprehensive benchmarking on main performance indicators against existing as well as alternative new designs, this burner type is an entirely new development. The final design was selected for its efficient mixing of combustion gas and air as well as its reduced emissions.

Wimmer, Dr. Gerald, Primetals Technologies Austria GmbH, Austria

Abstract: The iron and steel industry is the second largest global industrial CO2 emitter. Direct reduction using low-carbon hydrogen is the most promising solution to achieve the industry target of climate neutrality. The common solution is an EAF for processing of DRI which is only beneficial in case based on high-grade ores. However, most of the iron ores globally available is of lower grade and new solutions for processing of such lower-grade direct reduced iron is required. A two-step process combining a Smelter with a BOF converter can handle such lower grade ores and is predestined for implementation in existing integrated plants. Depending on the capacity of the smelter required, round or rectangular smelters are used.

Wu, Lijia, 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

Yang, Prof. Tianjun, University of Science and Technology, Beijing, China

Co-Author: Jianliang Zhang, University of Science and Technology Beijing • Zhengjian Liu, University of Science and Technology Beijing • Kejiang Li, University of Science and Technology Beijing

Abstract: In recent years, the situation of continuous growth of Chinese ironmaking industry is changing with a lower growth rate. The development of Chinese large-scale blast furnace has made a great achievement. The number of blast furnaces with a volume larger than 4000 m3 is 23, while that larger than 5000 m3 is 9. With many new technologies such as refinement of raw materials, increase of blast temperature, increase of PCI rate, optimization of BF operation, the fuel consumption has decreased with a high utilization factor, while ultra-low emission has become the new target for many enterprises. Due to the huge production capacity and the existence of many medium-sized blast furnaces, there is still a long way to go to achieve energy-saving and emission-reduction. Chinese ironmaking experts are devoting to the development of low-carbon ironmaking technology and carrying out fundamental research on hydrogen metallurgy. Meanwhile, HBIS Group has planned to constructed a 1.2 million tons metallurgical demonstration project through international cooperation. Baowu Group has started the cooperation with other organizations to to develop nuclear energy for hydrogen production and hydrogen energy metallurgy. China is working hard to develop new processes to promote the development of the ironmaking industry.

Zhang, Dr. Yale, Hatch, Canada

Co-Author: Ronald Timmer, Algoma Steel Inc. • Aaron Tanninen, Algoma Steel Inc. • Ian Cameron, Hatch Ltd. • Yale Zhang, Hatch Ltd. • Luke Boivin, Hatch Ltd.

Abstract: Management of the hearth drainage, and the related hot metal and slag liquid levels, is one of the most important requirements to maintain a smooth and productive blast furnace (BF) operation. Hatch implemented a Casting Guidance Model (CGM) in support of Algoma Steel’s efforts to enhance their casting practice. The CGM provides real-time information to help the operators as they adjust the furnace casting practices using richer information about the hearth status. The CGM provides two key benefits; (i) real-time monitoring, visualization, and forecasting of hot metal and slag levels; and (ii) scenario analysis to simulate the impact of casting practice changes in response to changing blast furnace conditions. This paper outlines the CGM functionality and the implementation strategy at Algoma BF7. Benefits to the casthouse operation and furnace performance are discussed.

Zhang, Dr. Yale, Hatch, Canada

Co-Author: Nicholas Aubry, Hatch • Julie Kim, Hatch

Abstract: Using AI and Digital Twins to Improve Blast Furnace Operations Julie Kim, Nicholas Aubry, Mitren Sukhram and Yale Zhang Abstract: Successfully managing an ironmaking plant is a complex task. The need to satisfy the competing interests of efficiency, quality, and cost, while adhering to ever-higher standards of safety and sustainability puts immense pressure on people and systems. To meet the stringent expectations for today’s blast furnace operation, operational intelligence is a must for plant managers, process engineers, and shop-floor operators. Hatch’s Digital Twin Platform fulfills this need; it delivers operational intelligence from three strongly linked aspects: integration, intelligence and interaction. In this paper, a use case of a blast furnace digital twin is presented. The case focuses on predicting the thermal state of blast furnace using artificial intelligence. Advanced outlier filtering and stacked machine learning models, are used together with fundamental blast furnace mass and energy calculations. The model provides operators with a consistent understanding of the furnace thermal state, which results in a better hot metal temperature and silicon control strategy. The paper concludes by summarizing best practices learned from blast furnace digital twin development and deployment. Key words: Blast furnace, Ironmaking, Digital Twin, Artificial Intelligence