Marco Rische, ABP Induction Systems GmbH, Germany

Co-Author:
Josef Gahleitner, Primetals Technologies Austria GmbH
Axel Walther, ABP Induction Systems GmbH
Martin Ennen, ABP Induction Systems GmbH

Abstract:
The steel industry is the second largest industrial emitter of CO2 emissions worldwide. The increasing pressure to reduce these emissions is leading to a move away from fossil fuels in the future. Alternatives are the use of green energy via the generation of DRI/HBI for pig iron production with green hydrogen. In further processing, this opens up new possibilities for alternative applications in the steel making and rolling mill processes, which offer almost CO2-free heating of the material, both in the melting process and in reheating. One of these alternative processes is induction. The energy input is achieved directly via the electromagnetic field into the material to be heated. The process is dynamic, easily controllable and, if green energy is used, almost CO2-neutral. Both in the melting process and in the area of reheating, the established processes can thus be complemented and thereby reduce the emissions of the overall process. The hybrid addition of induction heating systems not only improves the emission behavior in the overall process at manageable investment costs: Due to lower burning rates of the aggregates and an extremely good stirring effect during the melting process, the process is excellently suited for melting aggregates at the lowest possible energy consumption with good mixing of the target analysis in the melt and with higher yields as conventional processes contribute. With the dynamic behavior in the heating process due to the direct energy input into the material, the induction heating process is also a good alternative to the existing gas furnace for reheating. The induction furnace can be positioned complementarily upstream or downstream of the gas furnace. Both variants enable a reduction of the total energy consumption as well as the gas consumption and thus a directly measurable CO2 reduction in the reheating process.

Fabian Krause, SMS group, Germany

Co-Author:
Andreas Kemminger, SMS group
Hans-Jürgen Odenthal, SMS group
Johannes Wilkomm, RWTH Aachen University
Johannes Henrich Schleifenbaum, RWTH Aachen University
Christian Goßrau, RWTH Aachen University
Manfred Wirsum, RWTH Aachen University
Florence Cameron, RWTH Aachen University
Huanhuan Xu, RWTH Aachen University
Heinz Pitsch, RWTH Aachen University

Abstract:
Electric steelmaking using scrap generates 80% less greenhouse gases than the blast furnace route. The electric arc furnace (EAF) is usually equipped with natural gas (NG) burners that melt down the scrap and decarburize the melt. Many activities are underway to replace NG, at least to a large extent, with hydrogen. Hydrogen has complex combustion properties, e.g. high burning velocity, low ignition energy, low volumetric energy density, and wide flammability limits, which places high demands on the burner design. Here, additively manufactured (AM) burners open up new avenues with regard to the gas/water routing, and thus show significant advantages over conventional burners when using hydrogen. These avenues are being explored within the HyInnoBurn project. This project is part of the German Clusters4Future initiative (supported by the German Federal Ministry of Education and Research, BMBF) with partners from the entire hydrogen value chain and focuses on the development of additively manufactured burners for flexible use of NG and hydrogen. The presentation gives an overview of Computational Fluid Dynamics (CFD) simulations, manufacturing approaches and experiments at small-scale 50 kW and 450 kW burners. All burners are additively manufactured with a new and pure copper powder. High resolution combustion simulations show the fundamental flame structure, temperature and species distribution as well as the influence of increasing hydrogen amounts. While the 50 kW burner is examined with advanced laser diagnostics, the 450 kW burner is tested in an industrial sized furnace at the Gas- und Wärme-Institut (GWI) Essen. Difficulties and possible solutions for the change from NG to hydrogen are discussed.

Itsaso Auzmendi, Sarralle, Spain

Abstract:
Success stories towards CO2 neutral steelmaking via hydrogen-based technologies Sarralle has decades of experience on helping steelmaking companies in the challenge of decarbonization and sustainability. Moreover, through their division Environment & Energy, we can offer technological solutions for industrial sectors related to the Circular Economy and Energy, including the integration of green hydrogen technologies in the industry. Sarralle offers oxy-combustion and hydrogen technology applicable to EAFs, Ladle and Tundish Preheaters, Reheating Furnaces and Oxyfuel-Cutting, thus enabling savings in natural gas consumption and the total decarbonization of these equipment. Sarralle, together with one of its European customers, has implemented their oxy-combustion and hydrogen technology in a ladle pre-heater, using 100% hydrogen. The Spanish company owns also a prototype of a reheating furnace at scale, designed to operate with 100% hydrogen, both with air and oxy-combustion burners, and they are currently working on the conversion of an industrial reheating furnace in a European steelmaking plant, for the installation of their oxy-combustion and hydrogen technology in one furnace zone. The goal of this cutting-edge technology offered by Sarralle is to optimize the process efficiency as well as to reduce the emissions generated in existing installations, replacing the air used as an oxidizer with oxygen, being able to keep natural gas as a fuel, or taking a step further by using 100% green hydrogen. By using green hydrogen, all CO2 emissions are eliminated as only water vapor is generated in its combustion.

Martin Fein, Andritz AG, Austria

Co-Author:
Andreas Rechberger, Andritz AG
Vasile Jechiu, Andritz AG
Philippe Reynes, Andritz AG

Abstract:
This paper reports on a strategy of alternative heating solutions for a continuous galvanizing line in order to prevent any direct CO2 emissions, increase efficiency and production at the same time. This is possible by replacing common natural gas-fired radiant tubes with a new electrical heating system without modification of existing furnace setup, minimizing down-time and reducing the OPEX (lifetime increase and easier maintenance). The system – developed by ANDRITZ - is based on existing and reliable technologies and eliminates NOx emissions completely. In addition, to electrical heating, an advanced type of hydrogen-ready burners was developed to replace the consumption of natural gas on direct fired furnaces – combined with decreasing respective CO2 emissions – potentially using green hydrogen. The performance of the new Green Hydrogen burners has been validated with CFD simulations, confirmed by laboratory tests with full hydrogen operation. This internal development started 2 years ago has been confronted to customers, then validated during detail study in partnership with one of our long term and key clients. The study confirmed the expected results and even more, leading us to go further, building dedicated test furnaces and schedule industrial tests. The electrical test furnace is already in use to validate customer specific configurations in real operating conditions.

Andrea Turolo, SMS group, Italy

Co-Author:
Pietro Della Putta, SMS group
Umberto Zanusso, SMS group
Jimmy Fabro, SMS group

Abstract:
An important area of application for hydrogen in steel production is the field of reheating and heat treatment furnaces. On the way to more environmentally friendly steel production SMS group has developed a flameless, extra-low NOx burner: the SMS ZeroFlame HY2. This burner can work with outstanding process and environmental performances on any given mixture of hydrogen and natural gas up to 100% of H2, thus accompanying step-by-step the transition to the hydrogen economy from the present paradigm based on fossil fuels combustion. Besides the CO2 emission reduction due to the use of hydrogen as an energy carrier – that reaches a net zero at 100% of hydrogen - the SMS ZeroFlame HY2 confirmed its high performance in terms of flame thermal profile and extra-low NOx emissions, and its high flexibility as it can operate in flame, flameless and over-boost mode at any percentage of hydrogen in the gas mixture. SMS ZeroFlame HY2 burner design was optimized with the help of Ansys computational fluid dynamics simulation software. The first set of burners was then tested in an experimental test furnace. Through this procedure, SMS was able to confirm the behavior of the burners and to experimentally validate the theoretical model. The first lot of SMS ZeroFlame HY2 burners will be installed and started up in the first half of 2023.

Stephane Mehrain, Fives Group, France

Abstract:
In current fast-evolving markets, Steelmakers are facing two types of simultaneous challenges. The first is related to new products and processes which require higher performance technologies and new digital solutions whereas a second challenge is overlapped with the need for green operations. Deep emission reductions are not achievable without innovation in technologies and materials. While innovative technologies are under development to use hydrogen, electrification and carbon capture, use and storage (CCUS), most of potential emission reductions are today coming from improvements in technology performances and in material efficiency. This paper presents the technology pathways to decarbonization and how innovations in technologies and materials contributes to both challenges through some examples in various fields of carbon steel and electrical steel processing. These advanced process technologies and digital solutions offer new avenues for steelmakers to expand their portfolio to higher-added value products, and to boost the productivity and environmental performance of their operations.

Alessandro Della Rocca, Tenova S.p.A., Italy

Co-Author:
Claudio Leoncini, Tenova S.p.A.

Abstract:
The European Green Deal, the Paris Cop21 agreement and the ‘Fit for 55’ climate package all set ambitious targets in terms of greenhouse gas emissions reduction. Consequently, European iron and steel producers need a paradigm shift to fulfill environmental regulations and to carefully evolve their processes towards low-carbon footprint technologies without losing competitiveness or profitability. To this end, both steel production stages, Upstream (up to liquid steel) and Downstream (from liquid to solid steel), need to implement an evolution or replacement of current technologies. Reduction of iron ores remains the most carbon intensive process and several technologies are currently under scrutiny for minimizing its carbon footprint. Anyway, more than 40% of European steel comes from scrap recycling with direct carbon emission intensity of about 130 kgCO2e/ton for the Upstream portion. In this case, reheating and heat treatment processes in Downstream, accounting for 50-190 kgCO2e/ton depending upon the product type, cover a relevant fraction of total direct carbon footprint of steel products. Consequently, the decarbonization of electric steel production must also take into account hot rolling and heat treatment processes. In this energy transition scenario, Tenova proposes a stepwise solution to the decarbonization of heating furnaces. After a first step of thermal efficiency optimization of existing equipment, electrification is pursued as far as possible to maximize energy efficiency. This is possible only up to a critical temperature, where other process constraints (scale formation, heating efficiency, production flexibility) come into play. Hydrogen and non-fossil fuels combustion are required for the final temperature increase, while also providing a protective atmosphere against surface oxidation. The sequence of implementation of these energy transition steps follows the availability of resources as foreseen in the energy transition scenario for Europe, thus providing to steelmakers a low-risk implementation of steel production decarbonization.

Sergio Martinez Muniz, Fives Stein, France

Abstract:
Following the global trend towards higher environmental sustainability/green industry, steel processing plants continue to develop new technologies, with new slab reheating process technologies offering major opportunities to help reach green steel targets, not only to minimize the carbon footprint but also to reduce plant operational expenditure. This paper introduces new equipment and services for reheating furnaces to reduce energy consumption, scale production and emissions. Multi-fuel combustion (including hydrogen) and energy recovery systems are fundamental new technologies that will also be reviewed.

Amanda Vickerfält, Swerim AB, Sweden

Co-Author:
Sichen Du, Hybrit Development AB
Johan Martinsson, Swerim AB
Joar Huss, Swerim AB

Abstract:
The melting progression of hydrogen direct reduced iron pellets containing metallic iron and residual oxides (flux, gangue and unreduced iron oxide) was studied experimentally at 1773-1873 K. It was found that the autogenous slag formed inside the pellet prior to the iron melting. The autogenous slag formation was initiated by the melting of FeO. The liquid FeO dissolved the remaining residual oxides, forming the autogenous slag inside the pellet pores. After the iron melted, the autogenous slag was released from the pores coalescing into droplets. Phase separation occurred as the slag droplets floated up to the liquid iron surface. The melting speed was found to increase with decreased degree of reduction. The reduction degree also affected the partitions of phosphorus and vanadium between slag and metal.

Sa Ge, Hatch Ltd., Canada

Co-Author:
Kamal Joubarani, Hatch Ltd.
Terrence Koehler, Hatch Ltd.
Ian Cameron, Hatch Ltd.
Chris Walker, Hatch Ltd.
Kyle Chomyn, Hatch Ltd.

Abstract:
The future of steelmaking requires changes to existing integrated process flowsheets and application of new technologies to achieve significant reduction of greenhouse gas (GHG) emissions, i.e., green steel production. One such novel approach is the use of direct reduced iron (DRI) coupled with an electrical smelting furnace (ESF) to produce hot metal for downstream steelmaking, and thus replacing the blast furnace (BF) – the biggest GHG emitting process step in the value chain. The DRI-ESF process capitalizes on the lower Scope 1 GHG emissions from direct reduction and electric furnace processes versus BF, as well as the effective gangue rejection and slag valorization capability of ESF to improve raw material flexibility. The complexity of the iron and steel value chain and the rapidly evolving decarbonization technology landscape mean that the implementation of the DRI-ESF concept requires bespoke flowsheet development and thorough assessment of many potential options to be effective. The present study examines various potential flowsheets centred around the DRI-ESF concept, considering the key choices in flowsheet development such as DRI reductant (hydrogen or natural gas or both), specification of intermediate product, grade and type of iron ore, ESF slag valorization, downstream steelmaking technology, and the ultimate transition to ESF-based direct steelmaking. High level process and cost models were developed to simulate archetypal flowsheets, and these flowsheet cases are critically assessed with emphasis on comprehensive economics, overall GHG emission benefits, and level of technical / implementation risks. Potential risk mitigation options, enabling / synergistic technologies, and preferred implementation scenarios were also identified and discussed.

Reinoud van Laar, Danieli Corus B.V, Netherlands

Co-Author:
Bart De Graaff, Danieli Corus B.V

Abstract:
The majority of steel to date is made by BF-BOF, but the iron- and steelmaking industry is more frequently evaluating alternative plant configurations to reduce CO2 emissions. These include DRP and EAF technologies, but also new electric smelter technology to convert low-grade DRI pellets to hot metal to retain BOF steelmaking plants. The development of this technology eliminates future constraints to DR-grade pellets and could allow usage of slag for the production of cement. However, there are many challenges in the process design of industrial electric smelter technology including carburization particularly when hydrogen is used for the production of DRI. This paper will address potential plant configurations including electric smelter technology. It will also address a preliminary assessment of electric smelter technology and metallurgy and identify challenges and risks.

David Rudge, Hatch Ltd., Canada

Co-Author:
Sa Ge, Hatch Ltd
Terry Koehler, Hatch Ltd
Chris Walker, Hatch Ltd

Abstract:
The future of steelmaking requires changes to achieve significant reduction of greenhouse 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 in the future when using hydrogen-DRI. This paper describes a method to improve the process yield and efficiency, using an electric smelting furnace technology. The smelting furnace (ESF) efficiently converts DRI into pig iron (hot metal), which can be used downstream in an EAF or basic oxygen furnace (BOF), or cast / granulated for future use. The smelting furnace leverages advanced furnace technology developed over 60+ years for ironmaking and ferro-nickel applications, and has also been demonstrated for direct steelmaking. These furnaces are operated continuously with high power and large throughputs. Technologies have been developed, tested, and optimized to ensure safe and efficient operation, and a long furnace campaign life. 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.

Andre Esterhuizen , Tenova South Africa Pty Ltd, South Africa

Co-Author:
Piet Jonker, TENOVA South Africa Pty Ltd
Marco Corbella, Tenova S.p.A.

Abstract:
With the global steelmaking industry’s focus on the decarburization of the steel making process, Tenova has developed iBlue®, a novel technology that combines conventional smelting furnaces with the Energiron® Direct Reduction technology - jointly developed by Tenova and Danieli - to replace the blast furnace process, using low grade pellets (± 62% FeO) as virgin iron sources. To maximize the yield of the hot metal produced, and provide operators with a flexible plant design that can cater for a wide range of inputs, key design decisions are required to ensure an optimal flow sheet. This paper explains in detail the decision making process in the DRI melter design, touching on raw material feed requirements, metal handling, carbon balancing, electrical system design and management of the off gasses produced in the reducing atmosphere. These concepts will be evaluated from both a control volume and process design point of view. The conduction of the melter process is closely connected to the DRI production process and there are substantial benefits in the interconnection of the ENERGIRON® plant and the melter from an overall quality and efficiency perspectives. The paper analyzes the benefits of a closed furnace design for this application, as it operates in a reducing environment, allowing for minimal losses of FeO to the slag. Lastly, slag conditioning and management is described: matching the chemical composition requirements for the cement industry (not possible using an EAF) is a key benefit of this solution which can be truly considered as the evolution of the blast furnace technology. Key Words Hydrogen, DRI, HBI, BF, BOF, EAF, FMF, H2, reducing gas, carbon footprint, decarburization, ENERGIRON ZR, CCS, CCU, smelting reduction furnace, OSBF, ENERGIRON

Bartosz Mertas, Institute of Energy and Fuels Processing Technology, Poland

Co-Author:
Robert Baron, Koksownia Częstochowa Nowa Sp. z o.o
Sten Yngve Larsen, Eramet AS
Michał Książek, Sintef AS
Anna Rodź, Institute of Energy and Fuel Processing Technology
Grzegorz Gałko, Institute of Energy and Fuel Processing Technology
Małgorzata Wojtaszek-Kalaitzidi, Institute of Energy and Fuel Processing Technology
Michał Rejdak, Institute of Energy and Fuel Processing Technology
Bartosz Mertas, Institute of Energy and Fuel Processing Technology

Abstract:
The carbothermal reduction process is used to produce manganese ferroalloys. One way to reduce CO2 emissions from the process in which coke is used would be to replace fossil carbon with renewable biomass carbon, which is considered to be carbon neutral. One of possibilities is to use bio-coke as a substitute for typical coke made of only fossil coking coal. Bio-coke can be manufactured on the basis of coking coal with the addition of materials of biomass origin. Blends for the production of bio-coke should have acceptable cokemaking properties to allow to produce bio-coke of appropriate quality. The paper presents the results of the on-going research project on the influence of the addition (up to 20%) of bio-materials of different origins to the coal blend on its cokemaking properties, i.e., Gieseler Fluidity, Arnu—Audibert dilatation and caking ability (Roga Index). The bio materials used in the research were raw and thermally processed waste biomass of different origins (forestry: beech and alder woodchips; sawmill: pine sawdust; and the food industry: hazelnut shells and olive kernels) and commercial charcoal. Presented results show that the amount of additive as well as the type of material affect the obtained coking properties. The presentation also contains the results of the quality parameters of bio-coke made on the basis of a coal blend with the addition of up to 20% of thermally processed biomass - charcoal. The evaluated parameters were: reactivity to CO2 (CRI), CSR post-reaction strength, structure and texture parameters. The presentation will also show the results of earlier research conducted at SINTEF: CO/CO2 reactivity, electrical resistivity and reactivity to MnO (slag-reactivity). Studies have shown that the quality parameters of the bio-coke produced on a large-laboratory scale meet the requirements for the reductant in the process of smelting manganese ferroalloys in submerged arc furnaces.

Ko-ichiro Ohno, Kyushu University, Japan

Co-Author:
Tatsuya Kon, Kyushu University
Taro Handa, Kyushu University
Yuki Kawashiri, JFE Steel Corporation

Abstract:
In an oxygen blast furnace trial using an experimental blast furnace, it was confirmed that the oxygen blast furnace could operate at a high pig iron ratio of approximately twice that of a normal blast furnace. Owing to the higher productivity of the oxygen blast furnace compared to the standard blast furnace process, the internal volume can be reduced while maintaining the same productivity. This trend can help utilization of lump iron ore, which is generally not used in current blast furnace operation due to the low strength and poor reducibility of lump ore compared to sintered iron ore. To evaluate the possibility of utilizing lump ore in an oxygen blast furnace, slag formation behavior at the lump ore and limestone interface was investigated in this study. In order to evaluate the slag formation behavior in the cohesive zone, the softening behavior between pre-reduced lump ore and a CaO substrate in an inert atmosphere was measured under loading conditions using a softening simulator. From the results, the following results were obtained. When the lump ore melt intrudes to the CaO substrate, the solid part of lump ore penetrates into the CaO substrate with deformation of the CaO substrate, and the greater the degree of melt intrusion, the more lump ore penetrates. The melt intrusion behavior into the CaO substrate is strongly related to the presence or absence of Ca2SiO4 phase at the initial melt formation temperature. At 1300°C or lower, the gangue composition at the outer part of the lump ore decides intrusion behavior. At 1300°C or higher, the average gangue component of the entire lump ore is the main factor to make intrusion behavior.

Michael Alter, ALTER Blast Furnace Consulting, United States

Co-Author:
Andrii Moskalyna, ISI NASU
Mykola Izumskyi, ISI NASU
Vitaliy Lebed, ISI NASU
Bogdan Kornilov, ISI NASU
Oleksii Chaika, ISI NASU
Volodymyr Naboka, PJSC Zaporizhstal

Abstract:
The article discusses results of calculations of energy and exergy balances in blast furnaces with possibilities of new and existing technologies for reducing carbon dioxide emissions and reducing coke consumption, increasing production of pig iron by injection into the hearth hydrogen and hydrogen containing fuel additives (coke oven, BOF, or natural gases), use of scrap, enriched top gas, increasing blast temperature, reducing heat loss and improving gas utilization. Calculations were carried out using original mathematical model developed in the ISI NASU for blast furnace total energy balance. There were assessed impacts of different technologies on reducing CO2 emissions and technical and economic blast furnace operating indexes in depending on changes in pulverized coal consumption, hydrogen and hydrogen-containing fuel additives rate and their combinations in a wide range. Have been determined limits of hydrogen and hydrogen-containing fuel additives for injection into the hearth of blast furnace, by the following factors: degree of direct reduction of iron, RAFT range, the availability of oxygen for blast enrichment and top gas temperature. Outcomes of study disclosed that CO2 emissions of blast furnace ironmaking can be reduced up to 25-30% by evolution of blast furnace operations which depends on investments, quality of raw materials, available energy, level of existing blast furnace operations technology. The effects of injection of preheated enriched top gas, clean scrap additives use, heat losses drop, actions to increase hot blast temperature, and optimization of gas distribution in the blast furnace on carbon dioxide emissions decreasing and technical and economic indicators of blast furnace operation were investigated. The results can be useful for determining the economic feasibility of different technological actions to reduce CO2 emissions in blast furnace ironmaking.

Mehdi Baniasadi, Paul Wurth S.A., Luxembourg

Co-Author:
Florent Mauret, Paul Wurth S.A.
Peter Kinzel, Paul Wurth S.A.
Fernand Didelon, Paul Wurth S.A.

Abstract:
The steel industry, especially traditional ironmaking is among the largest contributors of greenhouse gas emissions, attributable to approximately 7% of total emissions, because the Blast Furnace (BF) process was initially designed for the utilization of carbon-containing fossil fuels. Considering economic reality and CO2 emission targets, Paul Wurth has reassessed the blast furnace route and ended up with a solution named EASyMelt™, Electrically Assisted Syngas sMelter. In this contribution, an in-house numerical model (BFinner model) is utilized to investigate the EASyMelt™ concept for a blast furnace. First, the validation of the BFinner model with operation data of processes with medium to high levels of H2 load will be deliberated. Then, the model gives an insight into the feasibility of the EASyMelt™ with high H2 load and a minimum possible coke rate resulting in a significant coke saving.

Pratyush Kumar, M. N. Dastur & Co., India

Co-Author:
Arnab Adak, M. N. Dastur & Co.
Atanu Mukherjee, Dastur Energy Inc.
Saptarshi Bhattacharya, M. N. Dastur & Co.
Soukarsa Das, M. N. Dastur & Co.
Arunava Maity, M. N. Dastur & Co.
Kaushal Kumar Sinha, M. N. Dastur & Co.

Abstract:
Currently approximately two billion tons of steel are produced annually. The rapid industrialisation of developing nations has contributed to an addition of nearly one billion tons steel capacity over the past 20 years. CO2-intensive BF-BOF has been the preferred process method due to its scale, robustness, and feed flexibility. The potential to instantly replace BF-BOF with clean technologies like H2-based DRI or scrap-based EAF is constrained by the maturity of the technology, the economic impact of stranded assets, and the availability of resources (scrap & green H2) at the right quantity and price. Over the last decade, significant consolidation has happened in the steel industry, enabling steel businesses to optimize and reconfigure plant assets in order to achieve sustainable and effective production. Our work demonstrates that replacement of old inefficient BFs with DRI plants fueled by waste gas or syngas can be the most effective near-term decarbonization strategy for steel plants having multiple BFs and/or having facilities at multiple locations. Our case demonstrates how the use of HBI in BF can reduce CO2 emissions by about 1.5 mtpa while maintaining the same level of crude steel production in a large (around 10 mtpa) BF-BOF-based integrated steel plant. The BF productivity would rise by about 10% with an increase of 140 kg/thm HBI, helping to shut down two smaller inefficient blast furnaces. With the reduction of the coke rate by at least 45 kg/thm and around 140 kg/thm HBI addition in burden, the older smaller sinter & coke oven plant could also be decommissioned. Procuring power from renewable sources or a greener grid will reduce the usage of gas in inefficient power plants operation. Available gas has been considered for DRI plant operation. Other options for fueling DRI plants like syngas from waste and/or biomass gasification will also be further evaluated.

David Leigh, Rio Tinto plc, Australia

Co-Author:
Chris Dodds, Chemical and Environmental Engineering, The University of Nottingham
Michael Buckley, Rio Tinto

Abstract:
Rio Tinto has been working on technology pathways which do not require the use of coal for processing Pilbara iron ores to iron and steel for well over a decade. Use of natural gas, hydrogen and biomass as reductants has been studied with a unique option combining microwave energy with raw sustainable biomass (rather than char) showing strong potential. Testwork with single “briquettes” made from a range of raw sustainable biomass including agricultural wastes, purpose grown energy crops, macro and micro algae with Pilbara iron ore fines indicated the potential of the process at laboratory scale. Initial scale up to 1000 briquette batches confirmed the early testwork and has positioned the technology for development of a 1 tonne per hour continuous pilot plant.

Anderson Agra, Tecnored Desenvolvimento Tecnológico S.A., Brazil

Co-Author:
Ismael Flores, Federal University of Rio de Janeiro
Manoel Gonçalves, Tecnored Desenvolvimento Tecnológico S.A
Bruno Flores, Federal University of Rio Grande do Sul
Alex Campos, Tecnored Desenvolvimento Tecnológico S.A
Ronald Lopes, Tecnored Desenvolvimento Tecnológico S.A
Guilherme Gonçalves, Tecnored Desenvolvimento Tecnológico S.A
Stephen Potter, Tecnored Desenvolvimento Tecnológico S.A

Abstract:
The iron and steel production sector accounts for 7-9% of the total CO2 emitted worldwide, being one of the most energy-intensive and large-volume production industries. As a result, governments and companies are committed to mitigating its CO2 emissions, an important requisite for the future development of the steel industry. Most of the world's steel is obtained through the blast furnace-basic oxygen furnace (BF-BOF) route, with the blast furnace being responsible for roughly 90% of the total carbon emissions of the entire steelmaking route. However, reducing BF CO2 emissions is challenging due to the technology's high maturity and raw materials. Tecnored company has extensive experience developing cold agglomerated briquettes for its smelting reduction technology, which is 100% fed with self-reducing briquettes and fuel briquettes. With the increasing demands for CO2 reduction in the iron and steel sector and Tecnored background, two low-carbon briquetting solutions were developed for hot metal production (BF). The first one is a bio-briquette for cokemaking (BBC). The replacement of coking coals by biomass-based materials for coke production is challenging, usually limited to no more than 1-2% only. BBC has promising results indicating up to 10% replacement ratio while keeping high coke quality. The second low-carbon solution developed by Tecnored is the catalyzed briquette for blast furnace (CBB). CBB is a combination of carbonaceous sources (coking/non-coking coals, biocarbon, etc.), a catalyst (iron and calcium bearing materials) and binders, which is carbonized in mild conditions to produce a material with the ideal composition and strength for blast furnace application. The utilization of CBB associated with the sinter layers in BF has the potential to decrease reserve zone temperature hence coke consumption. In this study, the main characteristics and features of the briquetting solutions (BBC and CBB) were discussed regarding their potential for use, process impact and potential for CO2 mitigation.

Hedda Pousette, SSAB AB, Sweden

Co-Author:
Joel Carlsson, SSAB/HDAB
Niklas Kojola, SSAB AB
Pär Ljungqvist, SSAB/HDAB
Liviu Brabie, Swerim AB
Ulf Sjöström, Swerim AB
Erik Sandberg, Swerim AB
Magnus Heintz, Swerim AB
Xianfeng Hu, Swerim AB

Abstract:
The global climate crisis demands that CO2 emissions are reduced. This is especially the case for the steel industry, which contributes to 7% of annual CO2 emissions. Steelmaking using an Electric arc furnace (EAF) and hydrogen reduced Direct Reduced Iron (DRI) as iron input is a possible replacement for the blast furnace steelmaking route. All research work has been conducted within the Hybrit development project, a joint venture between SSAB, LKAB and Vattenfall. For steel production in the EAF, carbon-sourcing materials (typically anthracite and carbon in the steel scrap) play an important role as an alloying agent, a slag foaming agent, and a reducing agent. Biocarbon is investigated as a possible replacement for anthracite in order to eliminate fossil CO2 emissions during the melting of H-DRI in the EAF. This paper highlights development results from the Hybrit development program with focus on the application of biocarbon during the melting of H-DRI in a pilot scale EAF. The performance of several different biocarbon materials was evaluated in terms of carbon yield in the steel, slag foaming behavior, off-gas and dust compositions. Fixed carbon content, ash, and volatiles have varied between the tested biocarbon materials. Size and form have varied as well. The results show that biocarbon is a feasible replacement for anthracite. However, properties of the biocarbon have a significant impact on its performance during EAF steelmaking. This is an important aspect for the continuing development of a fossil-free steelmaking value chain.

Elsayed Mousa, Swerim AB, Sweden

Abstract:
Agglomeration is an essential part in the metallurgical industries, and it comes in the core of circular economy. The agglomeration can play a substantial role not only in enhancing the residue recirculation in the steel plant, but also in introducing the neutral biocarbon for replacing the fossil fuels and consequently mitigate the fossil CO2 emission. The agglomeration can be performed through different techniques such as sintering, pelletising, and briquetting. This study demonstrates the recent trends in pelletising and briquetting as potential pathways for sustainability transitions from the traditional iron and steel making route to the next generation H2-based steel route. Developing biocarbon briquette and/or biocarbon containing agglomerates with the quality fulfil the shaft furnace and/or electric arc furnace will be discussed. In addition, developing and optimizing pellets/briquettes using innovative binders are key approaches to improve the process efficiency, reduce the slag generation, and decrease the energy consumption. In this context, the developed agglomerates will be evaluated in terms of cold mechanical strength, hot mechanical strength, reduction behaviour, softening and melting which are essential parameters to judge the quality of the agglomerates. Keywords: Pelletising, Briquetting, Organic binders, Biocarbon, Recycling, Ironmaking, CO2 emission, Circular economy

Jaehong Kwon, Hyundai Steel Co. , Korea, Republic of

Co-Author:
Han sang Oh, Hyundai Steel Co.
Jong hyup Lee, Hyundai Steel Co.
Ga Eon Kim, Hyundai Steel Co.
Yu bin Lee, Hyundai Steel Co.
Byong Chul Kim, Hyundai Steel Co.

Abstract:
Carbon dioxide emission reduction in the steelmaking process has been raised as an important issue according to greenhouse gas emission regulations. Among them, the use of biomass resources, which are carbon-neutral materials, is expected as a way to solve environmental problems. Therefore, a study was conducted to utilize biomass in a blast furnace by replacing coke and pulverized coal. First, the basic properties of 10 candidate groups were investigated to evaluate the feasibility of using biomass in a blast furnace, and the biomass for utilize in a blast furnace was selected in consideration of the calorific value and energy density. Iron-Bearing Biomass Coke (IBC), produced by mixing coal, torrefied biomass and iron ore, was used to partially replace coke with biomass. Evaluation for strength and reactivity must be preceded for the input of IBC in a blast furnace. Therefore, Shatter Index (SI) and Coke Reactivity Index (CRI) were evaluated, and the upper area of the blast furnace was simulated using the Shaft Inner-reaction Simulator (SIS). In addition, the combustion characteristics according to the mixing ratio of pulverized coal and biomass were investigated in order to partially replace pulverized coal with biomass. The combustibility of biomass was evaluated by a combustion test using a Drop Tube Furnace (DTF). The effect of using biomass in the blast furnace was investigated, and the following conclusions were drawn. When coke and pulverized coal are partially replaced with biomass, gas utilization and combustibility are improved. As a result, it is possible to reduce greenhouse gases emitted from the blast furnace through the use of biomass.

Maéva Chrzaszcz, Hatch Ltd., Canada

Co-Author:
Mitren Sukhram, Hatch Ltd.
Richard Elliott, Hatch Ltd.
Ian Cameron, Hatch Ltd.
Mariam Sidawi, Hatch Ltd.

Abstract:
Nearly all Europeans steelmakers are considering a transition to direct reduced ironmaking and electric steelmaking – either in electric arc furnaces or electric smelting furnaces – as part of a decarbonization strategy. This paper discusses the application of biotechnologies to further reduce electric steelmaking emissions as steel companies aspire to achieve near-zero emissions. Fermentation of off-gas streams can convert carbon monoxide to a bioethanol by-product. Microalgae production is a candidate for carbon capture and sequestration to further treat these off-gases. Biochar can be used as a fossil-fuel alternative for reductants, carburizers, and/or energy sources. Biotechnologies as a pathway to near-zero emissions for electric steelmaking operations will be presented.

Yu-Chiao Lu, KTH Royal Institute of Technology, Sweden

Co-Author:
Chuan Wang, Swerim AB
Björn Glaser, KTH Royal Institute of Technology
Andrey Karasev, KTH Royal Institute of Technology

Abstract:
Replacement of the blast furnace process with direct-reduction (DR) process coupled to an electric arc furnace is the key to realizing low-CO2 steelmaking and a climate neutral economy for Sweden. Direct-reduced iron (DRI) can be produced from reduction of iron ore pellets with H2 or CO gases in a shaft furnace, or from heating of carbon-containing pellets in a rotary hearth furnace. The addition of biomass to the pellets increases the porosities and thus the reducibility of pellets in both processes. The volatiles released from biomasses contain some amounts of reducing gases, such as H2, CO, and CH4, which can also contribute to the reduction degree and kinetics. By using biomass-containing pellets, a lower reduction temperature or a shorter reduction period could be obtained in both DR processes, which increases process efficiency and decreases energy consumption. Hydrochar is a bio-coal produced from hydrothermal carbonization treatment of organic wastes. Hydrochar has high volatile content and it may also act as an effective organic binder, which can be used for iron ore pellets making and carbothermic reduction. In this study, two carbon-containing materials: a Lemon Peel Hydrochar (LPH) and an Anthracite were separately mixed with an iron oxide-containing material (pellet fine, PF) at a Cfix/O ratio of 0.7 for reduction. The mixtures were pressed into briquettes (~30 g) and heated up in N2 atmosphere at a heating rate of 5 K/min up to two final temperatures. The reduction degree of PF by the volatiles released from the carbonaceous materials was determined by heating up to 750 °C, and that by combination of volatiles and residual carbon up to 1100 °C. The significance of the obtained results for the gas-based and coal-based DR processes were discussed, followed by some concluding remarks at the end.

Francesco Fredi, Feralpi Group, Italy

Co-Author:
L. Angelini, Feralpi Group
Piero Frittella, Feralpi Group
A. Landini, Feralpi Group
M. Fusato, Feralpi Group
G. Foglio, Feralpi Group
C. Di Cecca, Feralpi Group
M. Tellaroli, Feralpi Group
E. Tolettini, Feralpi Group
Mattia Bissoli, Tenova S.p.A.
Mauro Gizzi, Tenova S.p.A.
Elia Gosparini, I. Blu Spa
Filippo Cirilli, Rina Consulting – Centro Sviluppo Materiali S.p.A
M. Bersani, Acciaierie di Calvisano

Abstract:
The substitution of the use of carbon sources in Steelmaking became in last years an even more important topic considering the necessity both to increase the possibility of reuse of the residues also from other sector and also to reach a condition of strongly reduction of the global use of carbon sources to arrive at a condition of zero CO2 emissions. In particular, Feralpi Group has followed this route since several years starting with trials of basket charging of alternative materials arriving in last configuration to totally substitute the coal injected by wall mounted lances with polymers obtained by the plastic residues. Thanks to this substitution Feralpi Siderurgica became fist EAF plant with only polymer injected by wall mounted lances and able to eliminate the solid natural carbon sources to enable a correct production process and an appropriate slag foaming. In this way enabling the demonstration of a feasible industrial approach for the use of alternative materials Here the activity of the first period of the OnlyPlastic project is presented. The industrial injection system is described, together with a new injector able to efficiently deliver the plastic residues into the Feralpi Lonato EAF, with the aim of promoting the reduction process and the slag foaming in a circular economy approach. The paper includes also the design and realization of an industrial injection system and a new injector able to inject efficiently the material into EAF to promote reducing process and slag foaming. Keywords: Steelmaking, EAF, Slag foaming, Circular Economy, Residues Coal Substitution, Injections, Polymers

Guenter Harp, Harp Process Chemistry Consulting, Germany

Abstract:
The use of green H2 as reductant shall lead to a CO2 lean ironmaking. The industrial demand of green H2 in the future cannot be supplied via own resources and must therefore be imported from regions with better prerequisites for green H2 as well as renewable electricity production e.g. MENA region. The problem to transport such big amounts of green H2 shall be solved by using liquid ammonia (NH3) as H2-carrier. One missing link in this H2 transportation chain is the availability of an industrial proven solution for the NH3-splitting to recover the H2. This is still under development. Using green methanol (MeOH) as H2 carrier does not have this problem, because industrial proven solutions exist for all parts of the H2 transportation chain as well as the chain closing the CO2 cycle related to green MeOH production and its use. Moreover 1 m³ of MeOH lead stoichiometrically to 148 kg of H2, whereas 1 m³ liquid NH3 lead stoichiometrically to 107 kg of H2. Besides that, MeOH is an interesting reductant for iron oxides due to its physical and chemical properties. Under normal conditions it is a liquid. Its boiling temperature is 65°C, which makes it applicable to vaporize with low temperature waste heat. Methanol vapor is chemically adsorbed on the surface of hematitic as well as magnetitic iron oxides. At about 320°C it causes a reduction to ferrous oxide FeO, H2 and CO2 as reaction products leading to a new concept for DRI production.