Breno Maia, Lumar Metals, Brazil

Abstract:
The practice of Slagplashing is already consolidated industrially. However, there are still uncertainties about the relationship of the boom parameters and their effects on the slag. This article presents a comparison of the similarity of two 300t converters, one in Ukraine and the other in Brazil, with the 1/10 scale acrylic model of the LASIP located at the Federal University of Minas Gerais and their respective slagsplashing patterns. The results will be compared using an improved version of the equation of motion in determining the jet penetration over the slag layer and the ejection of material to cover the refractory walls.

Bernhard Mitas, K1-MET GmbH , Austria

Co-Author:
Ville Visuri, University of Oulu
Johannes Schenk, Montanuniversität Leoben

Abstract:
The significance of iron droplets dispersed in BOF slag is researched regarding their contribution to overall refining kinetics. The droplet generation in the hot spot vicinity and their behaviour during their residence in the slag is modelled. Previously the consensus has been to focus on fine droplet dispersion when modelling BOF emulsion refining processes. This research indicates that the focus should be on mass transfer between the larger droplets and the slag when modelling emulsion refining.

Xiaomeng Zhang, K1-MET GmbH, Austria

Co-Author:
Stefan Pirker, Johannes Kepler University
Mahdi Saeedipour, Johannes Kepler University

Abstract:
Inclusion removal via slag absorption is considered a common way of lowering the inclusion amount in steel melt. However, the stage of inclusion separation at the steel-slag interface and further integration into the slag has been overlooked, leading to an overestimated inclusion removal efficiency. The current work conducts numerical simulations to investigate the interactions between a micron-sized spherical particle and steel-slag interfaces. By using the volume of fluid (VOF) method in combination with the dynamic overset mesh, this study is able to visualize the separation process, including the formation and evolution of a meniscus due to the wetting property of the system and the resulting capillary force-driven particle motion. The results indicate that the wetting angle and slag viscosity govern the interfacial separation. The role of capillary force is closely associated with the meniscus shape. It mainly acts as a driving force for particle motion arising from a decurved meniscus attached to the particle. It also imposes resistance when the meniscus is upcurved in the later stage of particle separation. In a low-viscosity environment, the positive capillary force results in significant particle acceleration and high enough particle displacement, thus separating the particle into the upper fluid. Whereas with the resistance from high viscous slag, no complete separation is observed, which corresponds to most situations in realistic steel-slag systems. It concludes that the dissolution of the particle happens near the steel-slag interface. Further, the effect of the dissolution-induced dynamic interfacial phenomenon, i.e., the Marangoni convection, is discussed. This study provides insight into the physics of inclusion removal at the interface which is essential for steel quality control.

Elizaveta Cheremisina, K1-MET GmbH, Austria

Co-Author:
Johannes Schenk, Montanuniversität Leoben
Emmanuel de Bilbao, CNRS, CEMHTI, University of Orleans
Zheng Zhang, CNRS, CEMHTI, University of Orleans

Abstract:
Density, surface tension and viscosity of the slag are key properties in steel refining. The accurate measurement of these properties is required for better process control of metallurgical operations. Aerodynamic levitation was employed to derive density, surface tension and viscosity of CaO-SiO2 and CaO-SiO2-Fe2O3 slags under contactless conditions. The levitation experiment was carried out under mixture of argon (80%) and oxygen (20%) gas atmosphere in the temperature range between 800 °C and 2000 °C for the density and 1500 °C and 2000 °C for surface tension and viscosity measurements. The quenched slag samples were analysed by Raman spectroscopy to provide information on the anionic structure of the silicate slag. It was observed that the addition of Fe2O3 to the silicate did not affect surface tension, while it influenced the density due to the reduction of non-bridging oxygens and viscosity due to the increase in the polymerization degree, especially for high silica-containing slag.

Jelena Brankov, Carmeuse SA, Belgium

Co-Author:
Dana Baricova, Technical University of Košice
Peter Demeter, Technical University of Košice
Jaroslav Legemza, Technical University of Košice
Róbert Findorák, Technical University of Košice
Branislav Buľko, Technical University of Košice
Sorinel Nafornita, Carmeuse SA
Francois Ponchon, Carmeuse SA

Abstract:
An ultimate goal of oxygen steelmaking process is formation of a basic slag using fluxes (lime, dolime) to remove impurities, like phosphorus and sulphur. Fluxes dissolution efficiency is important to achieve basic slag at the early stage of the process and protection of refractory lining. Limiting step in the slag formation process in the BOF represents lime dissolution kinetics in the primary acidic slag. Lime for the steelmaking process must be soft-burnt, as only this type has a high reactivity - ability to transition to the slag phase. Experimental work was carried out in a Marsh furnace to determine the mechanism of lime dissolution in the slag. Dissolution rate of different types of lime (soft, medium, and hard-burnt lime) in the typical BOF slag were compared. It has proven an excellent solubility for the soft-burnt lime, which is related to its high reactivity and a lower solubility for the hard-burnt lime. After determining the mechanism of lime dissolution in the steel slag, high-temperature experiments were performed in the induction furnace. Results were used to quantify the level of lime dissolution in the steel slag, compare it with a standard lime reactivity measurement, and for development of Value in Use Model. This in-depth study was conducted to understand the importance and to evaluate the influence of lime characteristics on BOF steelmaking process and their quantification through total cost of ownership. Besides lime dissolution, thermodynamic and the fluid dynamic approach was used, together with mass and heat balance. Value in Use Model proves the importance of lime characteristics and its impact on steel cleanliness, metallurgical results, productivity, and total cost of steel production including notably energy and CO2 balance. Model can calculate the savings and cost benefits for a given inputs, including lime and dolime,and operating parameters for respected case.

Oleksandr Kharchenko, Zaporizhzhia National University, Ukraine

Co-Author:
Oleksiy Smirnov, National Academy of Sciences of Ukraine
Olena Volkova, Iron and Steel Institute, TU Bergakademie Freiberg

Abstract:
The work is devoted to the analysis of physical and chemical processes in the high-temperature reaction zone (HTRZ), which is formed in steelmaking processes with oxygen blowing, such as converter production. Detailed thermodynamic analysis of HTRZ has been conducted, and parameters of liquid steel bath HTRZ have been determined: temperature, masses and chemical composition of metal, slag and gas phases. It is concluded that the carbon contained in the metal of HTRZ behaves as a catalyst for the transition of the iron into the gas phase and, accordingly, the irrevocable loss of iron in the steelmaking process. The results of the study allowed to build previously unknown fragments of equilibrium phase diagrams of the high-temperature region of systems "iron-oxygen" and «iron-oxygen-carbon». Another aspect of this study is removal of impurities from HTRZ. It is important process in which chemical elements are irretrievably removed from the space of the steelmaking unit. According to the temperature and the degree of removal into the gas phase, studied impurities can be divided into three groups: a) carbon, which is almost completely removed at a relatively low total oxygen content in the HTRZ and temperatures up to 2000°C; b) silicon, calcium, magnesium and phosphorus, which are almost completely removed into the gas phase in the temperature range of 2100...2800°C; c) manganese, sulfur, iron and aluminum, which are partially removed at temperatures above 2600°C. With an increase in the total oxygen content in the HTRZ above 15%, temperature increase sharply slows down, reaching limit of 2900°C at a total oxygen content of 20%. In this case, iron intensively escapes into the gas phase along with impurities. Therefore, blowing the steelmaking bath with oxygen at a very high rate is inappropriate, since it does not lead to a significant increase in the productivity of steelmaking unit.

Sourav Kumar Panda, Tata Steel IJmuiden B.V., Netherlands

Co-Author:
Aart Overbosch, Tata Steel Nederland Technology B.V

Abstract:
Lime is added during the converter process to remove phosphorus from steel. At the end of the converter process, some heats were found to contain undissolved lime, especially, the low phosphorous aim grades. The undissolved lime issue can be due to insufficient time after flux additions before the slag is tapped, formation of C3S/C2S layer on top of CaO flux which prevents further dissolution, and flux reach saturation limit which prevents further dissolution. One way to increase the lime dissolution is to increase the FeO content locally during the converter process. Dolomite is also added to the converter slag to control the MgO-C refractory dissolution by aiming right MgO-saturation level. Thermodynamic studies were performed using FactSage to determine “minimum FeO” content required within the converter slag which dissolves all lime that is added during the process. And, to determine the “minimum MgO” content required during converter slag to reach the MgO saturation level. The assumption in the current work is the fast kinetics of transfer of solid lime and dolomite to liquid slag when fluxes are added. FactSage-Macro function was used for determining the lime and MgO saturation limit for ~15,000 synthetic slag compositions within a specific range of composition and temperature. Regression formulas was then developed using the FactSage calculations which can calculate the “minimum FeO” and “minimum MgO” content for any given slag composition and temperature within that range. The formula will help design the local slag composition to avoid the undissolved lime issue and MgO-saturation level of the converter process.

Peer Eric Günther, Hüttenwerke Krupp Mannesmann GmbH, Germany

Co-Author:
Thomas Sturz, Hüttenwerke Krupp Mannesmann GmbH

Abstract:
Within the steel industry it is commonly known that slopping of slag and molten steel occurs in the BOF. Whilst searching for the reasons of slopping is still part of much research, it is also of interest how to manage these events of slopping and how to predict them as slopping events are problematic for environmental reasons and costly in their removal. Within the steel mill of Hüttenwerke Krupp Mannesmann GmbH (HKM) a technology for prediction of slopping is developed using acoustical analysis. The implementation of this technology is described, as well as the results to predict and to prevent excessive slopping of the converter vessel.

Anna Mayrhofer, Primetals Technologies Austria, Austria

Co-Author:
Franz Hartl, Primetals Technologies Austria
Krzysztof Pastucha, Primetals Technologies Austria
Bernhard Voraberger, Primetals Technologies Austria
Helmut Kühböck, Primetals Technologies Austria

Abstract:
"Steelmaking industry currently goes through the process of digital transformation heading to fully automated operations. The growing pressure from the global steel market for competitive steel making pushes towards increased plant automation. Highest productivity, flexibility, optimized product quality, precise and stable target achievement and at the same time lowest production costs are main demands for BOF and AOD operation. A continuous optimization and improvement of the converter process automation system is essential to reach the constantly increasing demands. In order to meet these challenges, we provide modular solutions for continuously closing the gap between the current situation of equipment as well as daily practice and the overall vision of an automated operation. We will illustrate how flexible cross process optimization leads to optimized steelmaking performance. Knowledge can be generated out of historical data and combined with digitalized know-how of experienced operators. This forms a digital knowledge base allowing assistance for maintenance and the handling of standard as well as exceptional operational situations. This paper drafts the journey to fully automtic converter steelmaking and possiblities to ensure state-of-the-art functionality, compatibility and cyber security throughout the life-time with subscription license models."

Bernhard Voraberger, Primetals Technologies Austria, Austria

Co-Author:
Anna Mayrhofer, Primetals Technologies Austria
Mario Hirth, Primetals Technologies Austria
Hartl Franz, Primetals Technologies Austria
Jakub Szcech, Primetals Technologies Austria

Abstract:
"Process automation and the process models are continuously improving in BOF converter steelmaking. The latest version of Primetals Technologies converter process model together with the maintenance friendly LOMAS offgas analysis system allows for a high share of heats with direct tapping. Still a steel sample is required to fulfill the quality requirements of steel production. Primetals Technologies has a broad portfolio of such measuring and sample taking solutions for all different plant configurations, installation space, heat size and measuring position. A very effective solution to measure at the tilted converter position is our horizontal measuring manipulator which is a proven and reliable technology with more than 13 references. A more advanced solution for highest productivity and safety is our new vertical sublance 2.0 for inblow measurement. The sublance can be equipped with a LiquiRob for fully automatic probe attachment and removal to eliminate manual work, as well as digital assistance tools, like the lance checker which ensures highest availability. Latest references of these measuring solutions at Arcelor Mittal Poland, Arcelor Mittal Brazil and at Ternium Brazil will be presented."

Thomas Schmidt, SMS group, Germany

Co-Author:
Markus Reifferscheid, SMS group
Uwe Plociennik, SMS group
Michael Hönig, SMS group
Michael Bruns, SMS group

Abstract:
Disadvantageous temperature management of ladles and their contained melts have a negative effect on energy consumption, throughput, and yield. In particular, the caster is highly influenced by any deviation from target temperature, which may come along with either low casting speed at high temperatures or even casting abortion at low temperatures. In this contribution, we present a solution for tracking ladle temperatures in a steel melt shop. In detail, the SMS group GmbH has developed an L2 process model to represent the current thermal state of each ladle in circulation in real time. This involves also empty ladles in waiting position. In addition, predictions on the melt and refractory temperatures can be performed, based on the planned process routing, which in turn define trimming values on standard target temperatures. The process model solves the heat conduction equation by means of the finite volume method in either 2D or 3D, whereby effects such as changes of the melt level, stirring of the ladle, or alloy additions are reflected. Moreover, model adaption to actual measurements from process and/or the coupling to other process models is possible. During production, the model receives actual process and equipment data (treatment times, alloy additions, refractory materials, heating power, …), as well as information on planned routing via a predefined database interface. The obtained computational results of the process model can be used in a variety of ways, in order to improve process performance, e.g. cost reduction at the primary aggregate, increase of throughput, or avoidance of ladle returners.

Hans Pronk, Tata Steel IJmuiden B.V. , Netherlands

Co-Author:
Cees Brockhus, Tata Steel IJmuiden B.V.
Sander Willemsen, Tata Steel IJmuiden B.V.
Dennis Berkvens, Tata Steel IJmuiden B.V.

Abstract:
Automation of processes in steel making are difficult and risky because of the high potential risks when mistakes in programming are made. To secure safe and stable automation you need time consuming test on the equipment/machines involved. In case of automation on production critical equipment, testing time will lead to loss of production. In Tata Steel Ijmuiden BOS plant the middle loading crane for hot metal or scrap is the most production critical compared to other cranes, so we decided to build a digital twin for this crane to speed up automation. This digital twin behaves exactly as the real crane and is connected to the backup PLC of the crane with the same software as in the real crane. With this digital twin we can test new software in a 3D environment before we install it on the real crane. Automation of these cranes can speed up without loss of production. Automation and operator skills are linked to each other. 99% of the time the automation will work but when it not works the operator need the skills to do it manual. For simple tasks it is not a problem but for complex tasks like charging hot metal in a vessel without fume emission or spilling hot metal it is more difficult. Another problem is to get operators working in a steel plant and to train them on the job with a mentor. The work done to create a digital twin for software development and testing is the base of the next step, a loading crane simulator for operator training. In Tata Steel Port Talbot there is already an simulator in operation and also other steel plants (not Tata) started with Steel Sim VR for training crane operators.

Angela Philipp, Alleima GmbH, Germany

Co-Author:
Felipe Beluche Lima, Alleima AB

Abstract:
Brazil is the largest producer of crude steel in the Americas by BOF process, and many challenges come along with the increasing market demand. In the BOF, a tubular wall hood structure has been showing premature failures related to the overlay welded tube technology in the hood wall. The main root causes were: thermal fatigue at 1800°C, hot spot formation, high heat-affected zone (HAZ) leading to stress cracking susceptibility, carburizing corrosion, and superficial wearing. Based on that, co-extruded tube technology (named composite tube) was the alternative chosen to enhance hood performance without compromising the BOF process. To rises safety and productivity, the composite tube has a 100% metallurgical bond assuring stable expansion, high heat exchange efficiency, better corrosion resistance, and less rough surface finishing. It was highly suggested to many other mills due to similar and existing reported cases. The paper describes the product co-extruded composite tube and the first successful installation in a tubular wall hood of a BOF. Keywords: BOF Hood; Co-extruded composite tube; Corrosion

Kyunghwan Kim, Hanyang University, Korea, Republic of

Co-Author:
Joohyun Park, Hanyang University

Abstract:
One of the most effective ways to reduce carbon emissions in the oxygen steelmaking process is to lower the hot metal ratio (HMR) in basic oxygen furnace (BOF). However, if the HMR is lowered, the amount of oxygen blowing during decarburization in the BOF converter increases due to a lack of heat source. As a result, the amount of the deoxidizer increases because the end point oxygen content in the molten steel increases, which results in a deterioration of the cleanliness of molten steel. Therefore, this study was conducted to ensure the molten steel quality even at a decreased HMR about 10%p compared to the current level to reduce carbon emission in a BOF steelmaking. An appropriate amount of silicon in hot metal was presented to maintain the lowered HMR, and a method of refining phosphorus when the silicon content in hot metal is varied for the lowered HMR was presented. Finally, even if the amount of scrap usage increases due to the application of lowered HMR operation, a process was improved to resolve the tramp elements issue.

Bart van den Berg, Danieli Corus B.V, Netherlands

Abstract:
Despite the fact that the price of scrap is usually higher than that of hot metal, environmental regulations are forcing ironmakers to decrease hot metal production as a key source of CO2 emissions. Steelmakers are for this reason looking for ways to increase the scrap ratio in the BOF charge mix. An overview of existing technologies and methods for increased scrap utilization in converter-type furnaces is set out in this paper. The study also deals with the economic and environmental reasons for increased scrap usage.

Champion Chigwedu , HT-PEACS LLC , Germany

Abstract:
Oxygen Steelmaking Reliable Production of Low Sulphur Steel Grades Without a Ladle Metallurgy Furnace The annual production of the Steelplant in question is 5 million metric tons of Flat Rolled Products. A significant percentage of the product mix requires final Sulphur levels of less than 50 ppm (0.0050 wt% [S]). When these steel Grades were scheduled, special steps were needed to minimize Downgrades and Cast Sequence Interruptions. The mandatory steps to be followed were: A -Desulphurize the incoming Hot Metal to 10ppm [S] or less B -Skim the “HECK” out of the Hot Metal transfer ladle, without regard to Yield losses C –Use only special low Sulphur scrap metal both at the BOF and at the Ladle Treatment Station as coolant D –Use special Low Sulphur Alloy Materials A careful study of the difference in chemistry between the final BOF-Slag and the required final LTS-Slag for a successful, final low Sulphur was carried out. In the end, new special steps, namely; E –Targeted control of the amount of BOF carryover slag F –Complete deoxydation of steel and carryover slag at BOF-Tap using Designed Deoxydation Cocktails G –Intensive and Efficient stirring at the LTS helped; -Reduce Hot metal skim losses, -Minimize Scrap metal cost -Optimize the use of expensive special low Sulphur alloy materials. Author; Dr.-Ing. Champion Chigwedu Technical Director of HT-PEACS LLC, USA. Tel.: +1 (703-350-7698) Email: cchigwedu@gmail.com cchigwedu@yahoo.com

Breno Maia, Lumar Metals, Brazil

Co-Author:
Marcelo Duarte, Lumar Metals
Willian Lima, Lumar Metals
Marcelo Guerra, Lumar Metals
Bernardo Braga, Lumar Metals

Abstract:
The integrated plants suffer the need to adapt their processes to contribute to carbon reductions. One option of many BOF converters is the replacement of scrap with hot metal. Building on theories from the 80s and using modern computational mathematical simulation resources, Lumar developed an innovative lance tip with afterburner on the face. Patented product with the differential of being a lance with three tubes and supersonic post combustion nozzles. The results show an average increase in scrap percentage, shorter blowing time and integrity of the lance conditions.

Christopher Long, Hatch Ltd., South Africa

Co-Author:
Hamid Ghorbani, Hatch Ltd.
Robert A MacCrimmon, Hatch Ltd.
William Wang, Hatch Ltd.
Lori Hay, Hatch Ltd.
Kyle Chomyn, Hatch Ltd.
Samantha Jarrett, Hatch Ltd.
Luis Felipe Gomez, Hatch Ltd.
Jorge Luiz de Oliveira, Gerdau Acominas S.A.
Lucio Eustaquio dos Santos, Gerdau Acominas S.A.

Abstract:
Gerdau’s integrated iron and steel plant at Ouro Branco, Minas Gerais State, includes a melt shop containing two basic oxygen furnaces (BOFs). The primary hot metal charging crane of 340t capacity has suffered structural damage including cracking and local deformations to girders and trolley structures after more than 30 years of operation. This damage presented a threat to the continued campaign life of the crane. Critical risks associated with this damage necessitated a thorough technical assessment to quantify the current structural condition, determine likely failure modes, and investigate possible options for continued safe operation. A campaign life assessment was performed, and life extension strategies were developed to minimize risk, maximize production, and improved reliability conditions. Root cause analysis and subsequent fitness-for-service assessment were carried out, including a strength and stability assessment, identification of cracking mechanisms. This led to the development of a range of options for mitigation and the associated constraints / monitoring requirements / etc. These strategies included short-term local repairs and monitoring strategies that could be completed without interruptions to overall production, as well as with long-term repairs, reinforcements, and local platework replacements to extend the campaign life until a replacement crane is procured and installed. These actions were successfully implemented, thus allowing for reliable continued operation of the crane, with major financial benefits to the melt shop facility. Keywords: Basic Oxygen Furnace; Melt Shop; Overhead Crane; Charging Crane; Fitness-for-Service; Campaign Life Extension.

Cameron Soltys, Hatch Ltd. , Canada

Co-Author:
Kyle Chomyn, Hatch Ltd.
Hamid Ghorbani, Hatch Ltd.
Jürgen Cappel, Hatch Ltd. Consultant

Abstract:
An integrated steel plant including two Basic Oxygen Furnaces (BOFs) in one melt shop identified the need and opportunity to enhance the refractory campaign life and furnace shell life of the BOFs. Hatch worked with the steel plant to understand the mechanisms that influence the lifespan of refractory and vessel shell campaign lives, including review of refractory material selection and thermomechanical evaluation. Based on the findings from this study, various options for enhancing the life of the converter were evaluated. These included options for increasing the life of a replacement converter vessel such as improved cooling systems, altering the refractory system to reduce shell heat loads, and a new material of construction. Changes to the refractory material selection and operational practice to improve lining performance were also investigated. The enhanced refractory design and equipment improvements implemented by the steel plant has allowed an optimized converter operation with an extended refractory campaign life. This optimization also lead to a reduction in shell temperatures, which will result in longer vessel campaign life. This has led to improved productivity, with key recommendations from the study also being applied to other BOFs at the plant. Keywords: Basic Oxygen Furnace; Melt Shop; Performance Optimization; Campaign Life Extension; Refractory Design

Christopher Bryce, Vesuvius UK, United Kingdom

Abstract:
The challenge in front of us with this prototype system has been significant, not only how to increase the speed of repair material delivery into the hot furnace, but more significantly, to do this immediately after the furnace has been emptied of molten slag. Successful repairs have taken place with lining temperatures measured by digital pyrometry at +1600 °c. Our internal objective to deliver one tone of gunning mass in less than five minutes has been exceeded consistently reducing the overall repair schedule time which typically takes up to twenty minutes after a furnace cooling down period. High speed gunning has not only achieved a record average repair gunning rate of 244kg/minute. We have achieved this consistently without any cooling down period. High speed gunning likens itself to a formula one racing car strategy for steelmakers, with fast set up, repair, and removal of equipment, all aspects of the system from material formulation to the equipment specification is designed to minimize repair time. The total repair downtime of 10 minutes has been achieved. Allowing the steelmaking cycle to restart immediately. A recent 5-day study of the technology in a 325t BOF Furnace has delivered a repair area lining thickness increase of 147mm from the high-speed application between 1776 to 1851 lives of the furnace, during this period ten high speed repairs took place. The repair speed, lining thickness increase, and overall time saving has Exceeded the steelmakers expectations of what is possible in the lower cone area of the hot BOF furnace. In the following paper we will present the system design advantages and share the results from industrial trial of the system.

Günther Staudinger, Danieli Corus B.V, Netherlands

Co-Author:
Michael Skorianz, Danieli Corus B.V
Willem Heijne, Danieli Corus B.V

Abstract:
Since the startup of Danieli Converter Technology in 2011, several BOF revamping projects have been realized and converters have been successfully brought in operation. Beside to keep the costs to a minimum, the most important tasks for revamping projects are: • Enlarge the inner volume but reuse as much as possible existing equipment • Maximize the lifetime of the converter vessel • Shorten the delivery time by keeping the quality level • Keep the shut down time during erection to a minimum Some recent examples which fulfill these requirements are presented. Additionally two special topics are brought under attention: • Revamping a converter by reusing an existing trunnion ring • Developing a measurement system for online monitoring the vessel shell temperature as well as its deformation The reusing of an existing trunnion ring is not a regular case but sometimes this could give added value for steel plants. Such approach has been successfully applied for a 160 t BOF in the Ukraine and will be realized for 2 x 65 t BOF in India. To serve this purpose, Danieli Corus developed a special technique which avoids high demanding welding as well as machining on site. For the measurement of the vessel temperature, Danieli Corus has already such sensors successfully installed in converter plants. For the next generation, Danieli Corus further developed this sensor. The most challenging topic is, to create a sensor which can operate at ambient temperatures of more than 250° C, which means, that consequently any electronic equipment cannot be applied. The solution was found by using proven techniques from the prior century when electronics did not even exist. This new sensor is basically a combination of a mechanical part, which enlarges the vessel deformation by a factor 5 or more and an electric resistance which transforms the mechanical distance into an electrical signal.

Gerald Wimmer, Primetals Technologies Austria, Austria

Co-Author:
Glenn Gosseye, ArcelorMittal
Dominik Jakob, Primetals Technologies Austria
Bernhard Voraberger, Primetals Technologies Austria

Abstract:
"One of the two 330t BOF converters at AM Gent, Belgium came to the end of lifetime and in 2018 Primetals Technologies was awarded with the contract to revamp the converter. Focus topic during the design phase of the new converter was to optimized reaction volume and shape of the converter vessel to further improve yield and energy efficiency towards absolute benchmark levels. Well proven equipment solutions like the Vaicon Link 2.0 vessel suspension and the Vaicon Drive for converter tilting were employed for the new converter. Existing equipment was reused as much as possible and e.g. the existing Vaicon Stopper for slag retention at tapping was installed with minimum modifications only on the new converter. Another focus topic in this project was the optimization of the project execution and especially the installation sequence. To minimize pre-assembly works on site and consequently the risks for quality issues and time delays the converter was fully assembled at the manufacturers site and transported in two pieces – the lower part of the vessel with the vessel suspension and the trunnion ring fully assembled and the upper cone of the vessel. Hence, onsite in final position only one circumferential weld was required. An optimized transport concept including lifting of fully assembled converter with a total weigh of more than 380t above a pipe bridge were required. Thanks to good planning and preparation, the tight 35-day timeline for the revamp could be met without any interruption in the ongoing production of the second converter in the melt shop during the shutdown. In the paper the main design features of the new converter as well as the highlights of the installation job will be presented."