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

Abstract:
Opening of the conference by the chairman

Stefanie Brockmann, Steel Institute VDEh, Germany

Abstract:
Welcome address by the host

Frank Hohlweg, ArcelorMittal Bremen, Germany

Abstract:
123

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

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

Alexander Fleischanderl, Primetals Technologies, Austria

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

Markus Dorndorf, TENOVA LOI Thermprocess GmbH, Germany

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

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

Sean Boyle, Midrex Technologies, Inc, United States

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

Rénard Chaigneau, Baffinland, Netherlands

Co-Author:
Maarten Geerdes, Geerdes Advies

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

Maarten Geerdes, Geerdes Advies, Netherlands

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

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

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

Co-Author:
Peter Schmöle, Schmöle Consulting

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

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

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

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

Richard Elliott, Hatch Ltd., Canada

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

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

Rainer Radloff, RWTH Aachen University, Germany

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

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

Arash Tahmasebi, The University of Newcastle, Australia

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

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

Brody Brooks, The University of Newcastle, Australia

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

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

Peer Eric Günther, TU Bergakademie Freiberg, Germany

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

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

Nicholas Aubry, Hatch, Canada

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

Hiroshi Nogami, Tohoku University, Japan

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

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

Henrik Saxen, Abo Akademi University, Finland

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

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

Peter Warren, British Steel Ltd, United Kingdom

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

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

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

Abstract:
In recent years, after the commissioning of many blast furnaces, there are frequent problems such as hearth lining temperature raising, local overheating, abnormal erosion and so on, even many hearth lining breakout accidents occurred. Based on the production practice and investigation of blast furnace, this paper analyzes and researches the abnormal damage of hearth lining, obtains the main reasons and mechanisms of abnormal erosion, and proposes some effective technical measures and approaches to prolong the campaign life of hearth. The shape, position and liquid permeability of dead coke column have important influence on melting slag and hot metal discharge. The hot metal circular flow is the main cause of abnormal erosion of hearth lining. It is concluded that the blast furnace design must follow the theory of reasonable temperature distribution, control the reasonable distribution of temperature field in the bottom and hearth, attach importance to the optimization of hearth lining structure design, and construct the dissipative structure system of blast furnace with self-organized characteristics. In blast furnace operation, must pay attention to the stability of hearth operation, keep the hearth with good performances of gas permeability and liquid permeability, and control the shape, position and structure of hearth dead coke column. Strengthen the melting slag and hot metal management of hearth, especially control the process of tapping, restrain the hot metal circular flow along the edge of the hearth side wall, control the temperature distribution of hearth side wall and bottom, and restrain the abnormal erosion of hearth side wall lining. Promote the maintenance and rehabilitation of hearth lining function, add the titanium compound to protect hearth lining reasonably, strengthen hearth cooling management, reinforce the monitoring and control of hearth lining temperature, etc. The effective technical measures to prolong the campaign life of modern blast furnace are put forward.

Henrik Saxen, Abo Akademi University, Finland

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

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

Filipe Sathler, ArcelorMittal Tubarão, Brazil

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

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

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

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

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

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

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

Wim Van der Stricht, ArcelorMittal, Belgium

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

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

Yichao Hu, The University of Queensland, Australia

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

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

Damien Streiff, Zentralkokerei Saar GmbH, Germany

Abstract:
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Zion Guetta, thyssenkrupp Industrial Solutions AG, Germany

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