Chikashi Kamijo, 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.

Mehdi Baniasadi, 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.

Rongshan Lin, 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.

Nella Janakova, 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

Thomas Baumann, 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.

Olli Vitikka, 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.

Hauke Bartusch, 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.

Bernd Weiss, 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.

Christian Dengler, 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.

Claude Meisch, 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.

Henry Merten, 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.

Yale Zhang, 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.

Bart de Graaff, 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

Filipe Sathler, 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.

Michael Alter, 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.)

Yakov Gordon, 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.

Mohamed Efetürk, 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.

Nicholas Aubry, 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.

Stephan Höntsch, 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.

Elsayed Mousa, 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).

Yale Zhang, 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

Dieter Bettinger, 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.

Olivier Mersch, 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.

Thomas Hahn, 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.

Edward Long, 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.

Richard Willemsen, 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.

Gerald Wimmer, 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.

Yakov Gordon, 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.

Mohamed Bahgat, 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.

Hans Bodo Lüngen, 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.

Florian Markus Penz, 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.

Fuming Zhang, Shougang Group Co., Ltd., China

Abstract:
Increasing the blast temperature can effectively reduce the fuel consumption of blast furnace (BF) and promote the BF stable and smooth production, which is one of the important developing directions of green and low carbon ironmaking technology. The heat transformation process and heat transfer characteristics of hot blast stove (HBS) are researched. The relationship between heating area and blast temperature of HBS is expounded through the study and analysis of heat transfer mechanism, and the view point of increasing heat flux to improve heat transfer in HBS is put forward. The relationships between theoretical combustion temperature, dome temperature and blast temperature of HBS are researched. The technical innovation and practice of high blast temperature are introduced by applying low heat value BF gas and recovering flue gas waste heat of HBS by coupling preheating and energy ladder-level utilization. High efficiency utilization and high value conversion of low heat value BF gas, increasing blast temperature, reducing fuel ratio and CO2 emission are the key-common technologies of BF ironmaking in the future.

Paul Geach, 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.