Elina Fernö, Swerim AB, Sweden

Co-Author:
Elina Fernö, Swerim AB
Xianfeng Hu, Swerim AB

Abstract:
The ironmaking process utilising the blast furnaces releases a significant amount of CO2 into the atmosphere due to using coke/coal as reductants and fuels. Innovative technologies are needed to meet the Paris agreement and reduce CO2 emissions in the ironmaking process. Electrolysis, which employs electrons generated from electricity as the reductants, is one of these alternative technologies. When electricity produced from renewable sources is applied, and an inert anode is employed in the electrolysis process, the process will be completely green, yielding iron as a product and oxygen as a byproduct; meanwhile, no CO2 is released. In this study, we investigated the electrolytic reduction behaviors of pure chemicals (or synthetic chemicals) of wustite, hematite, and magnetite, as well as magnetite-type iron ore in the molten NaOH salt (kept at 500 °C). There was at Swerim (Luleå, Sweden) established a pilot-scale electrolysis reactor, in which the materials of interest up to 60 grams were tested at the cathode, and a graphite electrode was applied as the anode. A series of electrolysis reduction trials were conducted at a constant cell voltage of 1.7V to understand how iron oxides with different valence statuses are reduced and how the gangue materials in the iron ore can affect the electrolytic reduction process. The results show that iron oxides/ore can be reduced into metallic iron electrolytically in molten NaOH salt. There is a stepwise reduction of iron oxides from a high valence to a low one. The knowledge obtained in this study provides a better understanding of the electrolytic reduction behaviors of iron oxides/ore, thus assisting in developing a CO2-free molten salt electrolysis process for ironmaking when an inert anode is applied. Also, this study provides knowledge for the electrolytic reduction of other transition metal oxides in molten salt.

Ryota Higashi, Tohoku University, Japan

Co-Author:
Daisuke Maruoka, Tohoku University
Taichi Murakami, Tohoku University
Eiki Kasai, Tohoku University
Yuji Iwami, JFE Steel Corporation

Abstract:
The iron making industry consumes a large amount of fossil fuel derived carbon as heat source, reducing agent of iron ores and carburizing agent of reduced iron. Carbon is an essential element for an efficient ironmaking, although hydrogen is expected to be the substitution. The carbon recycling ironmaking process by circulating CO gas has been already proposed to achieve carbon neutrality. However, the production of hot metal is not considered in this process because CO gas is not utilized as a carburizing agent. In order to apply the carbon recycling ironmaking process to the production of the hot metal, new ironmaking process of carbon solidification using porous iron whisker and production of hot metal using recovered carbon-iron ore composite is proposed in this study. The lumps of iron whisker with high porosity, approximately 95% were obtained by heating the mixture of fine hematite reagent and biomass char at 950℃ for 75 min. The lumps were utilized as the catalyst of the carbon solidification reaction under the gas flow of CO at 600℃. The recovered solid carbon samples with different cementite/free carbon ratio were obtained by changing the reaction time. The composite made of the obtained carbon powder and hematite reagent was heated in order to proceed the reduction of the iron oxide and carburization of reduced iron. The molar ratio of carbon to oxygen in the composite was set as from 0.8 to 1.0. The composite started to be reduced at 700℃ and then reduction degree increased sharply at 900℃. The molten iron nuggets were observed on the surface of the composite samples heating up to 1300℃. These results indicate that the suggested carbon recycling ironmaking process may contribute to forward not only carbon neutrality but also rapid hot metal production.

Simon Wölfelschneider, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Thomas E. Müller, Ruhr-Universität-Bochum
Dennis Panke, Ruhr-Universität-Bochum
Michael Hensmann, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
This work presents the melt-recrystallisation process as a possible solution for the sustainable use of carbon-containing materials, that would otherwise be burned or landfilled. Of interest are for example residuals or carbonaceous co-products from pyrolysis processes. Although these materials consist almost exclusively of carbon, they are lacking major fields of application. The melt-recrystallisation process provides a pathway towards these applications, as the low-grade carbon products can be upcycled to a graphitic carbon nano material, generally referred to as graphene nano platelets (GNP). GNP are sheets of hexagonally arranged and covalently bonded carbon atoms in µm-scale, forming stacks of about ten atomic layers. There is a wide spectrum of applications for GNP, ranging from high end electronics to corrosion protection and industrial lubricants. However, the most promising field for large scale application are composite materials, especially as additives in polymers and cement, in which GNP can induce an improvement of the mechanical properties. The process concept is based on dissolving defined amounts of carbon residual in molten alloys containing Fe or Ni. Afterwards the carbon is precipitated under defined conditions, forming the GNP at the melt surface. The formed GNP must then be removed from the surface of the liquid melt, to avoid prolonged growth of the crystallites into larger graphite particles. Therefore, a concept for removing the GNP from the melt surface is designed and tested. Furthermore, the influence of alloy composition, annealing time, and cooling rate on the crystal structure of the produced carbon nano material are evaluated. Analysis methods include Raman microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results indicate that indeed various types of GNP can be produced via melt-recrystallisation. Nonetheless, the separation of the produced GNP from the melt surface provides a challenge and is also affecting the product quality.

Luca Neri, SMS group, Italy

Co-Author:
Luca Neri, SMS group Spa
Andrea Lanari, SMS group Spa

Abstract:
Reduction of CO2 emission in steel production and transformation to green energy sources demand a highly efficient and flexible power supply for electric arc furnaces (EAF). Integrated BOF routes usually provide very weak grids, which do not allow the connection of demanding EAFs without major changes in the power network topology. The new family of IGBT based electrical modules is capable of feeding EAFs from 5 MVA up to 350 MVA. A fully modular technology concept provides the demanded efficiency and power density in order to serve the needs of the green steel transformation. Using this innovative modulation, technologies and proprietary control algorithms, which take full advantage of the power electronic capabilities, ensure highest power transfer and lowest impact on the grid’s power quality. A real project case is showing the challenges and needs of the implementation of EAFs for green steel production, and how the fully modular technology allows our journey into a CO2 reduced and green energy powered steel production.

Wolfgang Linden, SMS group, Germany

Co-Author:
Alexander Feldermann, SMS group
Volker Paersch, SMS group

Abstract:
The metals industry is on its way to replace the high CO2 emissions generated by the use of fossil fuels with renewable energies in order to achieve climate-neutral steel production. Rising prices for fossil fuels and the increase in CO2 taxes are further incentives for switching to a climate-friendly energy supply. The time is now for SMS group to make the most of its unique core competencies, technologies, and partnerships to provide all climate-neutral processes from a single source. With its pooled expertise in process and energy management, SMS group is able to connect all plant areas to a cost-efficient power supply network. This is achieved through a central connection to the public AC grid and available renewable energy sources, for instance solar or wind energy, as well as to energy storage units that include battery storage systems. The paper explains, how DC ECO GRID from SMS group connects these to hybrid power networks (AC and DC), thus improving the plants' energy efficiency. Thereby a holistic solution from SMS group combines energy management consulting services, a defined business case, the development of concepts and solutions, and the integration of systems – all from a single source. The DC ECO GRID helps to provide a greener, more energy-efficient power supply for steel plants, both new and existing. In this way, it creates a link between a more environmentally friendly metals industry and new green energy supply systems.

Todd Astoria, Midrex Technologies, Inc., United States

Co-Author:
Matt Hargreaves, TUTCO SureHeat

Abstract:
The iron and steelmaking industry is experiencing rapid market change and technology developments. One of the key drivers for the market change is the need to improve the environmental impact of the processing routes. The reduction of CO2 emissions is one of the most important environmental goals facing the industry. The Direct Reduction (DR) – Electric Arc Furnace (EAF) is one of the most promising technologies to achieve CO2 reductions. In order to achieve the reduction, the DR plants are extending their fuel options to include green hydrogen. Hydrogen has great promise for the direct avoidance of CO2 from the DR route when used as the process fuel; however, hydrogen has drawbacks when applied as a fuel for heating the Process Gas in the conventional combustion-based heating unit operation. Generally, green hydrogen is produced from electrolysis. If hydrogen is used as a fuel in a combustion system, then it can reduce the CO2 emission compared to a typical fossil-based fuel. However, inefficiencies are introduced when electricity is used to produce hydrogen, which must then be transported to the facility. In order to overcome the inefficiencies then it is advantageous to use electricity to directly heat the Process Gas. This paper focuses on the advancements that are being made in the field of electrical heating of process gases in the Direct Reduction facility.

Sanjeev Manocha, LanzaTech, United States

Co-Author:
Tobias Plattner, Primetals Technologies Austria
Alexander Fleischanderl, Primetals Technologies Austria
Wim Van Der Stricht, ArcelorMittal

Abstract:
The Iron & Steel industry is in the decarbonisation era facing significant regulatory, political and technical challenges. Moreover, with aging Blast furnaces due for reline, steel mills are at critical decision-making moment to pick the most economic and sustainable solution. We believe that eliminating carbon emissions will be achieved through the integration of multiple technologies to deliver bespoke solutions suited to local conditions. Amongst the options is an innovative carbon capture and use technology developed by LanzaTech. LanzaTech converts carbon-rich gases into sustainable fuels and chemicals by a process of gas fermentation, with biocatalyst that feed on gases. LanzaTech’s naturally-occurring biocatalyst has been optimized to provide economic routes to ethanol and other chemicals from a variety of carbon-rich gas streams, including industrial off-gases from steel and ferroalloy mills, agricultural or MSW waste, and even CO2 from Direct Air Capture (DAC). By capturing the carbon contained in these gas streams, LanzaTech’s gas fermentation process reduces industry carbon emissions whilst producing chemical building blocks like ethanol that can be used directly for cleaning products or fragrances or converted to sustainable aviation fuels or the key ingredients needed for a broad range of consumer products including detergents, packaging and textile fibers. Products made with LanzaTech’s process offer an improved environmental profile and reduce greenhouse gas emissions by over 70% when compared to equivalent products derived from fossil fuels. This is the circular economy in action. LanzaTech technology has been successfully deployed in 3 commercial operating facilities at a steel and 2 ferro alloy mills, with 7 additional commercial plants in construction and several more in the engineering phase. The first European commercial scale plant, Steelanol, is soon due for commissioning at the ArcelorMittal Ghent combined with the Torero biomass project, with the objective of producing 80 million liters of bio-ethanol/year.

Saptarshi Bhattacharya, M. N. Dastur & Co., India

Co-Author:
Arnab Adak, M. N. Dastur & Co.
Atanu Mukherjee, Dastur Energy Inc.
Anindya Majumdar, M. N. Dastur & Co.
Arunava Maity, M. N. Dastur & Co.

Abstract:
While global CO2 emissions are set to reach around 40.5 GTPA by 2022, the steel industry alone contributes 7-10% of the total emission. The CO2-intensive BF-BOF route of steel production is pre-dominant and will continue for some time. Decarbonization of BF-BOF is limited by the economics of multi-point post-combustion capture and technology to replace coal. Dastur has designed a novel solution integrating gas conditioning unit, carbon capture unit, and combined heat and power (CHP) plant. Gas conditioning unit helps to increase CO2 concentration to >30% and to capture >85% of available CO2 from a single source, enabling carbon capture technology to work efficiently with the lowest $/Te. Additionally, H2 can be recovered from the H2-rich fuel gas stream at a marginal cost of <0.5 $/kgH2. Since CO2 concentration is >30%, a wide range of technologies (from steam-based amine to all-electric PSA/Cryogenic) can be deployed depending on CO2 purity requirement, net CO2 reduction target, electricity, and steam cost. Even steam and power sourcing options could differ depending on available waste recovery options in existing steel plant operations. Additionally, the deployment of carbon capture along with H2 recovery can enable a circular green economy through utilization of CO2 /H2 in downstream industries like aggregates, methanol based chemicals, Enhanced Oil Recovery, etc. The incentives and support from governments can accelerate decarbonization of steel further. This paper discusses the key design aspects, policy support and techno-economics of different options.

Michalis Agraniotis, Mitsubishi Heavy Industries EMEA Ltd., Germany

Co-Author:
Takashi Kamijo, Mitsubishi Heavy Industries Engineering, Ltd.

Abstract:
Decarbonization in Hard-to-abate industrial sector is considered as one of the key future challenges in Europe and worldwide towards reaching the targets of Paris Agreement. Electrification and use of hydrogen, are two emerging technologies which may become relevant for specific industrial applications. Nevertheless, carbon capture is already proven in the large industrial scale and is expected to play a key role in the decarbonization of these sectors through combination with permanent storage. MHI has more than 30 years’ experience in development and commercialization of its proprietary amine based carbon capture technology and has 14 industrial scale references, including the world’s largest post combustion CO2 capture project, Petra Nova. MHI has recently commercialized the “Advanced KM CDR ProcessTM”, which utilizes the new generation of its proprietary solvent KS-21TM. The new solvent has improved characteristics such as higher stability and lower volatility, and brings competitive advantages in terms of capex and opex for new carbon capture projects. In the present paper the experience from projects in Hard-to-abate sector like steel industry, is assessed. For the development of new large scale projects Feasibility and Pre-FEED study type of activities are combined together with specific test campaigns in dedicated mobile test units. In this way the impact of specific flue gas composition on the performance of the process and quality of captured CO2 from steel industry can be analyzed, so that the outcome can directly facilitate the design of the large scale project.

Kerstin Stenzel, thyssenkrupp Uhde GmbH, Germany

Co-Author:
Holger Thielert, thyssenkrupp Uhde GmbH
Dirk Scheckreiter, thyssenkrupp Uhde GmbH

Abstract:
The process of treating raw coke oven gas (COG) to generate a clean fuelgas is a well-known process nowadays and generates a number of valuable saleable side products. Simultaneously the combustion of clean COG causes CO2 emissions which will be more costly in future at most places. It is worth to think about other types of using COG which help to reduce the greenhouse gas emissions of the coke plant and even of the steel mill. By further upgrading COG can be applied for the production of chemicals or be used as reducing agent in the blast furnace as well as in the process for production of direct reduced iron. In addition to that the CO2 captured at the stack of a coke oven gas battery and the hydrogen extracted from the COG offer a promising opportunity for the production of a new range of chemicals improving the carbon footprint any further.

Sebastian Bock, Rouge H2 Engineering, Austria

Co-Author:
Gernot Voitic, Rouge H2 Engineering

Abstract:
RGH2’s novel chemical looping based system can directly convert CO, CO2 and N2 rich blast furnace gas (BFG), coke oven gas (COG) and basic oxygen furnace gas (BOFG) into high purity H2 with inherent CO2 capture. The produced hydrogen can be utilized to substitute coal in the blast furnace and decarbonize steel plants, or to decarbonize plant-integrated heat and power generation systems. Based upon results in RGH2’s 100 kW OSOD On-Site-On-Demand demo plant (TRL 6) [1], the process produces high-purity H2 (>99.99%) and pure N2 (98.5%) as products, while sequestrating a carbon dioxide rich stream without energy penalty [2, 3]. In the specific case of nitrogen-containing gases (BFG, COG, BOFG), RGH2’s 3-step system enriches the CO2 content up to 50%. Only a downstream separation of nitrogen is required for CO2 sequestration up to 99% capture rate. Thus, the whole system can be an important building block to decarbonize the integrated steel plants. [1] Voitic G, Legerer C, von Hofen F, Beese-Vasbender P. Deponiegas zur Wasserstoffproduktion nutzen. GWF Gas + Energie. Sep. 2022; 163(Sep). https://gwf-gas.de/aktuelle-ausgabe-9/ [2] Bock S, Zacharias R, Hacker V. Co-production of pure hydrogen, carbon dioxide and nitrogen in a 10 kW fixed-bed chemical looping system. Sustain. Energy Fuels Mar. 2020; 4(3):1417–26. https://doi.org/10.1039/C9SE00980A. [3] Bock S, Zacharias R, Hacker V. High purity hydrogen production with a 10 kWth RESC prototype system. Energy Convers. Manag. Sep. 2018; 172(May):418–27. https://doi.org/10.1016/j.enconman.2018.07.020.

Peter Glodek, GEA Bischoff GmbH, Germany

Co-Author:
Jens Lange, GEA Bischoff GmbH
Marcel Zillgitt, GEA Bischoff GmbH

Abstract:
With the goal of reducing greenhouse gases to prevent global warming above 2 °C, industry is facing an unprecedented challenge. In this context, the reduction of CO2, as the main driver of global warming, represents a sensible and sustainable solution from many points of view. On the one hand, there is increasing national and international pressure regarding energy and CO2 saving solutions. On the other hand, there is also an opportunity to reduce operating costs in long term by a new sustainable orientation. Particularly in the context of sharply rising certificate costs for CO2, a trend is emerging that a decisive step must be taken in the direction of sustainable and ecological industrial processes. The iron & steel industry is well aware of these issues; many plants have already taken the first step to energy and decarbonization optimization. A much-discussed approach is to substitute coke or natural gas with hydrogen, preferably produced climate-neutral, for the reduction of iron ore. Despite these process optimizations, the direct emission of CO2 should still be avoided. Chemical absorption by means of amine solution has become established as a commercially proven downstream solution. The absorption process requires a very low content of residual impurities in the off gas, which can be ensured by using advanced gas cleaning technologies. In addition to indirect CO2 reduction, direct heat recovery from the energy-rich process is particularly well suited here for solvent regeneration, whereby surpluses can still be used to cover the company's own electricity consumption and / or compressed air generation. In this context, an overview of the sustainability goals described above is given to focus on the expanded importance of emission control.

Hubert Fouarge, CRM Group, Belgium

Co-Author:
Frédéric van Loo, CRM Group
Jan Wiencke, ArcelorMittal Maizières Research
Maria Martinez Pacheco, Tata Steel Nederland Technology B.V
Loredana di Sante, Rina Consulting – Centro Sviluppo Materiali S.p.A

Abstract:
In order to allow steelmakers to comply with ever stringent environmental constraints, TACOS project aims at evaluating solutions bringing significant decrease of CO2 with consequently decrease of others main pollutants (a.o. NOx, SOx, VOC’s, dioxins and dust emissions). Following alternative heat inputs are investigated : I. Alternative solid fuels with or without pre-processing’s; II. Waste gas recirculation (case studies are ArcelorMittal Fos, selective lay-out and Tata Steel IJmuiden, non-selective lay-out); III. Combustible gases for injection at strand surface; IV. High temperature fumes produced in an external combustion chamber. Combinations of these solutions will also be tested to reached a replacement of 100% of the solid fuel. For evaluation of the impact of these solutions on sintering process performances and emissions, tasks consists in modelling work (mathematical model), lab trials, sinter pot trials and industrial measuring campaigns and trials. These solutions have significant impacts on Blast Furnace process, so a special focus is also placed on their impact on sinter quality (especially on its vertical segregation) and BF performances. For that purpose a wide set of complementary tools not use in usual industrial practice is available amongst the project partners. At this stage of the project, a replacement rate of the solid up to 80% was tested for the selected alternative solid fuels (pyrolyzed biomass) without significant impact on sinter quality and productivity. Based on the pot trials results, industrial trials will be performed in ArcelorMittal Gent. Blast furnace gas injection at sinter strand surface was tested up to 10% replacement of the solid fuel while the hot fumes injection at strand surface allowed to reach 35% with limited productivity drop. This research is funded by the Research fund For Coal and Steel (RFCS), project # 847322-1, June 2019 to June 2023.

Johan van Boggelen, Tata Steel IJmuiden B.V. , Netherlands

Co-Author:
Hans Hage, Tata Steel Nederland Technology B.V
Christiaan Zeilstra, Tata Steel Nederland Technology B.V
Koen Meijer, Tata Steel Nederland Technology B.V
Dharm Jeet Gavel, Tata Steel IJmuiden B.V.
Chris Barnes, Tata Steel IJmuiden B.V.

Abstract:
HIsarna is a new and breakthrough process for the production of liquid hot metal from iron ore. It is a smelting reduction ironmaking process which is being developed by Tata Steel at the site in IJmuiden, the Netherlands. It will reduce CO2 emissions compared to the blast furnace route and the process is also ideally suited for combination with carbon capture technology. A CO2 emission reduction of 50% without carbon capture has already been demonstrated. The pilot plant has been in operation in campaigns since 2011 and significant modifications were made to the plant between the different campaigns. In the past few years significant steps were made to achieve stable process conditions and the focus is now moving more and more to plant reliability and availability in order to extend the duration of individual process runs and improve productivity. In addition work is also ongoing to increase circularity and valorise revert streams in order to maximise sustainability. This paper will address the most recent process results and some of the ongoing initiatives at the HIsarna pilot plant.

Kaijun Zhang, Sinosteel Equipment & Engineering CO., LTD., China

Co-Author:
Jinfeng Zhu, Sinosteel Equipment & Engineering CO., LTD.

Abstract:
According to the International Energy Agency, global energy-related CO2 emissions in 2019 were about 33 billion tonnes, of which nearly 14% were generated by the iron and steel industry, while the energy consumption and emissions of the iron and steelmaking system accounted for about 70% of the total energy consumption and emissions of the whole iron and steel process, and the development of low-carbon iron and steelmaking technology is an effective way for the iron and steel industry to achieve low-carbon development and green and sustainable development. Sinosteel actively practices the low-carbon and green development strategy. In July 2022, the hydrogen-rich carbon cycle oxygen blast furnace pilot project was successfully put into production, and in the subsequent experiments, key technologies such as 1200°C gas heating technology, gas CO2 removal technology, hydrogen-rich gas/decarbon gas heating and blowing were realized one after another, and the 1200°C high temperature gas self-circulation blowing and hydrogen-rich smelting were carried out under oxyfuel smelting working conditions The industrialization test of the hydrogen-rich carbon cycle oxygen blast furnace (HyCROF) process has been completed. A milestone of 30% reduction in solid fuel consumption and 21% carbon reduction has been achieved (as of November 2022). The new process is safe, stable, smooth and efficient, with strong resistance to fluctuations, low manufacturing costs and good compatibility with traditional manufacturing processes. This paper will introduce the new HyROF process and its engineering practice milestones with a view to providing a reference for the industry.

Kristina Beskow, UHT Uvån Hagfors Teknologi AB, Sweden

Co-Author:
Caroline Asplund, Uvån Hagfors Teknologi AB
Mårten Görnerup, Metsol AB

Abstract:
The transformation of the iron- and steelmaking industry into a fossil-free production system is challenging as you need to maintain productivity and product quality throughout the transition. The transition will likely have to be carried out in several steps over time where parallel production in both old and new systems must be managed, and where it is important for the steel makers to always maintain the iron balance in the plant. The introduction of a metal granulation unit can facilitate the transition by enabling the iron producer to operate without constraints from downstream steel-making operations and handle large excess pig iron flows during the transformation. Granulation of iron with the GRANSHOT process has proven to be an efficient way to resolve difficulties in the iron balance in integrated steelmaking plants as it decouples the ironmaking and steel-making operations when required, producing a ready-to-use granulated pig iron product (GPI). The process is today widely used for rapid solidification of various types of metals and has been well established on the Indian market for handling large flows of excess pig iron from the BF. In the GRANSHOT process, liquid metal is transformed into solid granules instantly using a high-capacity water granulation process. The process can handle large capacities, up to 360 tph, and can be implemented adjacent to the existing BF allowing granulation directly from the torpedo. The granulated pig iron product is well suited for handling in many metallurgical processes and can be used either as a part of the internal feedstock in the existing/new plant or sold as a commodity to other operators, as valuable iron feedstock.

Oday Daghagheleh, Montanuniversität Leoben , Austria

Co-Author:
Johannes Schenk, Montanuniversität Leoben, K1-Met GmbH
Michael Zarl, K1-MET GmbH
Heng Zheng, Montanuniversität Leoben
Manuel Farkas, K1-MET GmbH

Abstract:
Alternatives to fossil fuels are worth developing to shift to carbon-free iron making. Accordingly, replacing coal, coke and natural gas with H2 is the current trend. H2 is mainly produced through steam reforming and partial oxidation, which are not carbon neutral. A promising method to produce H2 is the decomposition or pyrolysis of natural gas using plasma technology. If the required energy for pyrolysis is provided from a renewable source, the CO2 footprint can be further minimized. Using thermal plasma pyrolysis in combination with hydrogen-based iron making in a fluidized bed can lead to an enormous decrease in CO2 emission. Thermal plasma converts electrical power to thermochemical energy and offers temperatures up to 10000 k. This temperature range requires no catalytic effect for the decomposition reaction to occur. The other advantages of plasma are the relatively small and simple technology, high-efficiency rate, low energy demands, and high grades of Carbon Black (CB) products besides the enriched H2 gas. CB, as a worthful byproduct, can be forwarded for applications in, e.g., the mobility, plastic, or agriculture industries. The methane pyrolysis is tested on a laboratory scale using a DC-transferred plasma arc system with a maximum power of 8 kW, providing a voltage range of 20-100 V and a maximum current of 150 A. The arc is initiated between a hollow graphite cathode and the graphite pin anode. The plasma gas (2l/min Ar) and methane (1-1.5 l/min CH4) are introduced to the reaction zone through the cathode. The off-gas could flow out for further analysis, and the arc could be seen through the openings at the top. The results show a CH4 conversion rate of 50 to 95 % depending on the testing parameters. The produced carbon black is fluffy and fine with high purity. Its structure can be amorphous or turbo.

Klaus Franz, Primetals Technologies Germany, Germany

Co-Author:
Gerd Becker, Primetals Technologies Germany
Klaus Weinzierl, Primetals Technologies Germany GmbH

Abstract:
"In the production of green steel, it is necessary to provide green hydrogen in sufficient quantities. This can be produced from green electricity by means of electrolysis. It is particularly important to produce the hydrogen as cost-effectively as possible. To achieve this, on the one hand the electrolyzer has to be operated at the highest possible utilization rate, and on the other hand only when energy costs are low. This means a conflict of objectives, which can be resolved by supplementing the electrolyzer with a battery energy storage system. This combination requires an intelligent predictive control system that actually operates this production process at its optimum cost. The paper describes a model-predictive approach that takes into account energy costs, capital costs, and the costs due to wear of the entire plant. The approach is universal and can easily be extended to include other plant components, such as a direct reduction plant, a hydrogen storage unit or a wind power plant. Simulation results show the advantages of the approach."

Daniel Ernst, Montanuniversität Leoben , Austria

Co-Author:
Johannes Schenk, Montanuniversität Leoben
Michael Zarl, K1-MET GmbH
Isnaldi R. Souza Filho, Max-Planck-Institute for Iron Research

Abstract:
Carbon Direct Avoidance (CDA), Smart Carbon Usage (SCU) and Circular Economy are strategic pathways that the European Steel Association's members created to reach a CO2-neutral European steel industry. Climate change can only be tackled by reducing the anthropogenic greenhouse gas emissions, particularly CO2 ones. The iron and steel industry must also contribute to mitigating CO2 emissions, as it accounts for 5.7% of the European Union's overall emissions and is even responsible for 7% of global anthropogenic CO2 emissions. To achieve the goals of the European Green Deal and reduce emissions by at least 55% from 1990 levels by 2030, today's steel industry and its processes must be completely transformed. Highly promising process technologies use hydrogen (H2) as the primary reducing agent instead of carbon-carrier substances (coke) to simultaneously reduce iron ores and achieve the climate target, thus following the CDA pathway. The Hydrogen Plasma Smelting Reduction (HPSR) exploits the highly energetic hydrogen species (e.g. H, H+) existing in a hydrogen-containing plasma arc as reducing agents for the ore. The high energy of such hydrogen plasma species helps overcome the reaction’s activation energy, leading to a 15 times higher reduction potential than the gaseous molecular hydrogen. The plasma species are created by the thermal energy of a DC-transferred arc between a hollow graphite electrode (HGE) and the melting bath, enabling a one-step direct production from iron ore to steel. Introducing iron ores with different pre-reduction degrees into the reaction zone (plasma/melt interface) influences the hydrogen utilization degree, the total process time, and the metal phase's microstructure. With this knowledge, optimal combinations of pre-reduction states via direct reduction and subsequent processing with hydrogen plasma to crude steel can be achieved to obtain the highest H2 utilization and optimal steel quality.

Henri Pauna, University of Oulu, Finland

Co-Author:
Daniel Ernst, K1-MET GmbH
Michael Zarl, K1-MET GmbH
Isnaldi R. Souza Filho, Max-Planck-Institute for Iron Research
Hauke Springer, RWTH Aachen University
Marko Huttula, University of Oulu
Johannes Schenk, Montanuniversität Leoben
Timo Fabritius, University of Oulu
Dierk Raabe, Max-Planck-Institute for Iron Research

Abstract:
Hydrogen plasma smelting reduction (HPSR) has the potential to be a viable solution for both reducing metal-bearing oxides and treatment of metallurgical sidestreams for metal recovery. However, thermal plasmas are known for their erratic and sometimes unpredictable behavior where the plasma may e.g. jump from place to place or have circular movement from side to side around the furnace. Furthermore, plasmas are highly dynamic entities, as their properties change rapidly depending on, to name a few, the plasma composition, electron density, and length. Since the composition of the ore will change in the reduction process, the plasma’s properties will also change during the smelting reduction. The need for online in situ process control is evident to keep the metallurgical process and the application of plasma aligned with the desired end-product reduction degree, composition, and quality. To address the demand for process control, the reduction of iron ore was studied at two lab-scale HPSR set-ups at the Montanuniversität Leoben and Max Planck Institute for Iron Research together with a demonstration-scale facility at K1-MET GmbH. Optical emission spectroscopy (OES) was used to provide a qualitative outlook on the HPSR process from an OES point of view by looking at the radiating species within the plasma and linking them to what is happening inside the furnace. As a measurement method, OES offers a way to monitor the plasma's composition, temperature, electron density, and other characteristics from a distance so that the plasma is not affected by the measurement itself. Since the focus is on process control, the aspects of OES as a process control tool to monitor the plasma are discussed.

Arun Kamalasekaran, KTH Royal Institute of Technology, Sweden

Co-Author:
Pelle Mellin, Swerim AB
Christopher Hulme, KTH Royal Institute of Technology

Abstract:
Ferronickel (FeNi) alloys are widely used to manufacture stainless and heat-resistant steels. They are also used as an alternative binder in tools, replacing Ferro-Cobalt. Typically, FeNi alloys and alloy powders are produced by processes that use carbon as a reductant and emit large volumes of greenhouse gases. In the current work, FeNi alloy powders with varying compositions were produced by directly reducing Fe2O3-NiO powder mixtures using hydrogen to replace carbon as the reductant. This could prevent millions of tons of greenhouse gas emissions each year in Sweden alone, and reduce energy consumption significantly. The mixtures of Fe2O3 and NiO powders were directly reduced using hydrogen in a horizontal tube furnace in which the products were analysed using a gas analyser based on photoacoustic spectroscopy. The preliminary results from the gas analyser indicated that the mixtures reduced completely at a temperature of 700°C within 45 minutes. This was confirmed using X-ray diffractometry (XRD). The XRD data revealed the absence of oxides in the reduced powders and the presence of a single solid phase: gamma (FCC) or two solid phases: alpha (BCC) and gamma (FCC), depending on the ratio of the iron and nickel oxide powders in the initial mixture. Analysis using energy-dispersive X-ray spectroscopy in a scanning electron microscope showed that the average composition of a mixture of oxide powders that contained a mass ratio of 78 wt% iron and 22 wt% nickel was 85 wt% iron and 15 wt% nickel. This is promising enough to justify further investigation. Successful application of these results could replace traditional pyrometallurgical processes with a clean, lower-energy production route and thereby save large amounts of carbon emissions and energy.

Durgesh Gupta, H2 Green Steel, Sweden

Co-Author:
Anatoliy Meyko, Midrex Technologies, Inc.
Marco Perato, Paul Wurth Italia S.p.A.

Abstract:
H2 Green Steel is on a mission to decarbonize hard-to-abate industries, and the steel industry is a prime place to start. Steel production is the source of 7-9% of global CO2 emission, 5% of CO2 output in the European Union, and 14% of CO2 generated in Sweden, the home country of H2GS AB. Sweden possesses an abundance of natural resources necessary to support green steel production via the direct reduction-electric arc furnace route (DR-EAF). H2 Green Steel is bringing together the technology expertise of Midrex in processing iron ore into steel products, creating green hydrogen with giga-scale electrolysis, and developing a circular supply chain to become the first commercial-scale supplier of green steel by 2025. The story of how H2 Green Steel decided to undertake a steel project in northern Sweden – 45 mile south of the Arctic Circle, development of the technical scope of the project, and what will be involved in the steel mill reaching its design capacity of 5 million metric tons/year is the focus of our presentation. We will discuss the further steel-related plans of H2 Green Steel and how the Boden project will provide the technical blueprint for future green steel projects.

Gunilla Hyllander, Hybrit Development AB, Sweden

Co-Author:
Christer Ryman, Hybrit Development AB
Marcus Henriksson, Hybrit Development AB
Hannes Wikström, Hybrit Development AB
Petrus Hedlund, Hybrit Development AB
Damian Guido, Hybrit Development AB
Nicklas Eklund, LKAB
Per Lundström, LKAB
Hedda Pousette, SSAB AB
Anna-Maria Suup, Hybrit Development AB
Per Hellberg, Hybrit Development AB
Jenny Wikström, LKAB
Shabbir Lakdawala, LKAB
Joel Carlsson, SSAB AB
Niklas Kojola, SSAB AB
Johan Riesbeck, Hybrit Development AB
Gunilla Hyllander, Hybrit Development AB

Abstract:
The iron and steel industry contributes globally with a share of up to 7% to greenhouse gas emissions. The goal of the HYBRIT initiative is to realize a fossil-free iron and steel production value chain. In this value chain the fossil CO2 emissions associated with the traditional blast furnace route are eliminated by using a 100% green hydrogen based direct reduction process. Starting from today's conventional natural gas based direct reduction technology, a shift to hydrogen as reduction gas introduces significant changes to the process chemistry and thermodynamics. A direct reduction pilot plant, including all safety installations required for hydrogen operation, has been designed and commissioned to develop best practices under semi-industrial conditions. The plant has a capacity of 1 tonne DRI per hour. Typically, the plant is run in campaigns where continuous operation takes place for a period of about 6-8 weeks. After initial design and construction of the pilot plant the trials started at the end of 2020 with natural gas and continued in early 2021 with the use of hydrogen as reduction gas. This paper provides key operational results from H-DR test trials conducted in the approximately 43 weeks of operation until today. DRI and HBI products have been successfully produced on pilot-scale under stable process conditions using 100% green hydrogen as reduction gas. Sponge iron produced with hydrogen as reduction agent is a carbon-free product. This DRI product has better physical, mechanical, chemical and reactivity characteristics compared to conventional DRI produced with natural gas. The results also demonstrate the technical feasibility to define a process window for production of DRI and HBI in an industrial DR plant based on green hydrogen.

Matthew Boot-Handford, Calix, Australia

Co-Author:
Mark Sceats, Calix
Geoffrey Brooks, Swinburne University of Technology
Phil Hodgson, Calix
Andrew Okely, Calix
Matthew Gill, Calix
Thomas Dufty, Calix
Isis Rosa Ignacio, Calix
Bintang Ayu Nuraeni, Swinburne University of Technology
Andrew Adipuri, Calix
Yun Xia, Calix

Abstract:
Calix is extending the application of its indirectly heated Calix flash calcination (CFC) technology to the decarbonisation of iron and steel production. The Zero Emissions Steel TechnologY (ZESTY) can be used to process low- and high-grade iron ore fines to a hydrogen direct reduced iron (H-DRI) product, avoiding the need for pelletisation or agglomeration. The small particle size range of the iron ore charge facilitates fast rates of metallisation allowing for significantly shorter residence times (in the order of 60s) and lower temperature operation than a conventional blast furnace such that the stickiness problem is avoided. Pilot-scale testing at Calix’s Centre for Technology Development in Victoria, Australia has shown that the ZESTY technology can produce a H-DRI product approaching commercial grade. The ZESTY technology is compatible with intermittent operation and can therefore be heated using renewable energy sources. ZESTY is targeting the theoretical minimum hydrogen use of 54 kg/t H-DRI as green hydrogen is used only as the reductant and is recycled in the process. Several scenarios are being explored for the downstream processing of the ZESTY DRI product including hot briquetting, direct flash melting and processing to green steel through integration with an electric arc furnace. Calix’s Low Emissions Intensity Lime and Cement (LEILAC) technology can be used to supply a zero-emissions lime fluxing agent to the EAF and other steel making processes. This paper will introduce the technology and discuss the status of ZESTY pilot testing and development.