Continuous Performance Monitoring and Calibration of Model and Control Functions for Liquid Steelmaking Processes
PerMonLiSt project objectives
The main objective of the research project was to improve, for the different stages of the liquid steelmaking process route, the continuous monitoring of the process performance as well as to ensure the permanent reliability of used dynamic process models and control rules. For this purpose, methods and tools have been developed involving the application of innovative and comprehensive performance indexes and strategies for automatic calibration of model and control parameters.
By these developments the following benefits should be achieved for the liquid steelmaking processes:
The developed tools have been coupled to an integrated approach and tested exemplarily for the most important liquid steelmaking facilities of the electric steelmaking route, i.e. for electrical arc furnace (EAF), ladle furnace (L)F, vacuum degasser (VD) and argon stirring plants.
The project started at July 1st 2016 and ended at December 31st 2019. Involved partners in the research were:
|Centre for Research in Metallurgy|
|Feralpi Siderurgica S.p.A.|
|Centro Sviluppo Materiali|
|Peiner Träger GmbH|
The research has received funding from the European Union’s Research fund for Coal and Steel (RFCS) under grant agreement No. RFSR-CT-2016-709620.
PerMonLiSt achieved results
In a first step, the available process models and required process data have been described and assessed regarding current accuracies for the EAF and secondary metallurgical ladle treatment processes at PTG, Feralpi/Lonato and Tata/Aldwarke, respectively. Data acquisition and model functions for EAF and ladle treatment processes at PTG as well as EAF process at Feralpi/Lonato and Tata/Aldwarke steel plant have been completed.
Process and model performance indexes have been defined for assessment of process behaviour and related model calculations in electric steelmaking processes. The analysed correlations between process performance indexes and operating practices show different significances. The most significant correlation for all studied EAFs of the industrial partners is given between metallic yield and specific oxygen consumption (see Figure A). The relation of specific energy consumption decreasing with increasing productivity in EAF depends on the characteristics of the furnace and its operation. The desulphurisation efficiency in ladle treatment shows positive correlation with the volume of applied stirring gas. Such correlations were used to appropriately adapt related operating practices. Analysed correlations between model and process performance indexes reveal systematic errors of the respective model for certain ranges of process operation.
Figure A: Correlation between specific O2 gas consumption and metallic losses for different EAFs of industrial partners
Regular ranges for defined process performance indices have been defined which are used within enhanced monitoring and alert functions regarding process behaviour and performances. At Feralpi Lonato steel plant such functions have been included in the newly installed on-line system EAFPro covering the EAF as well as the subsequent ladle treatment processes until teeming in tundish. The implemented monitoring functions comprise also new control charts with statistical evaluations of relevant process parameters and performance indices. Regarding enhancement of process monitoring, PTG has laid the focus on the EAF process. A suitable new human machine interface (HMI) has been designed and installed within their manufacturing execution system (MES) to support the operator in end-point control of the EAF process (see below). Furthermore, operating practices for EAF and secondary metallurgy have been adapted via appropriate configuration of the MES. For the secondary metallurgical ladle treatment, the specification of target temperature and time for delivery of a heat to the caster has been extended to take into account the position of the heat in the casting sequence. This information is used for dynamic adaptions of defined variable set-points in the operating practices (e.g. electrical energy input in LF) based on predictive model calculations.
The operating instructions at Feralpi Lonato plant have been adapted regarding practices with charging of 2 or 3 scrap baskets, charging and injection of carbon as well as injection of oxygen in the EAF. Charging of 2 scrap baskets results in lower electrical energy consumption for cases with sufficiently high scrap densities. The charging and injection of carbon is reduced in cases of too high carbon contents analysed in LF for previous heats. Additional increase of injected oxygen during EAF refining phase reduces carbon content further on with lowering electrical energy consumption and tap to tap time but also with decrease of metallic yield. The management of optimised oxygen injection as well as charge and injection of carbon in order to achieve maximum metallic yield, target carbon content in steel and sufficient slag foaming in EAF is supported by related control rules. Figure B shows an example for control of oxygen injection using the calculated slag oxidation status (SOS = calculated slag weight / reference slag weight) and appropriate thresholds for adaption of the injection practice (based on reference slag weight of 5 t).
Figure B: Logics of control function implemented at Feralpi Lonato for adaption of oxygen injection using slag oxidation status (SOS)
For applications with large number of model and control parameters, auto-calibration methods based on regression analysis with least-squares fitting and artificial neural network have been chosen, while approaches using Unscented Kalman filters (UKF), moving average corrections or KPI (key performance index) based heuristics were found to be suitable for on-line heat-to-heat adaptions of few parameters with rare measurements.
BFI has set-up an off-line calibration procedure for the parameters of the dynamic EAF model installed at PTG furnaces based on regression analysis with least-squares fitting on a defined number (e.g. 200) of last produced heats. This procedure can be called after a certain number (e.g. 100) of newly produced heats in order to keep the parameters adapted to the respective scrap, plant and process conditions. For the secondary metallurgical temperature model an on-line batch-to-batch adaption of identified (significant) parameters distinguished for 3 different routes (with 3 different LFs) has been developed using an Unscented Kalman filter (UKF) approach. Figure C exemplarily shows the resulting evolution of the electrical energy efficiency for one ladle furnace with an initial decrease of this efficiency which is later recovered again.
Figure C: Batch-to-batch adaption of electrical energy efficiency at ladle furnace of PTG steel plant
CRM has set-up a parameter calibration for their EAF model based on the same Kalman filter technique. It is important to select the most significant parameters and to adapt not more parameters in one step than the available number of temperature measurements for the related heat. The convergence speed of the Kalman filter should be adjusted by appropriate selection of the covariance matrix of applied process noise, so that the parameters converge on average over 10 -20 adaption steps.
CSM and Feralpi have developed an artificial neural network solution (ANN) for auto-calibration of the scrap basket composition at Feralpi Lonato plant (see Figure D). The sterile content of scrap also has to be taken into account in the slag weight which is estimated by the used EAFPro model to assess the slag oxidation status (SOS). This is a KPI mainly used at Feralpi Lonato plant within control rules for oxygen injection during the EAF refining phase (cf. Figure B). Another developed method for auto-calibration of the sterile content in scrap uses a moving average over the difference between calculated and measured tap weights of steel.
Figure D: Auto-calibration loop for scrap basket composition at Feralpi Lonato plant using an ANN
Furthermore, a temperature model for ladle treatment between tapping at EAF and teeming in tundish has been set-up by CSM and Feralpi which is also based on a calibration of model parameters via statistical analysis with moving average adaptions. The auto-calibrated model calculations are used for predictions of arrival temperatures in LF and CC. Together with defined acceptable limits for these arrival temperatures, the model predictions are used to support the operator in control of the thermal state evolution along the whole electric steelmaking route. This kind of temperature control together with the already mentioned adaptions of oxygen injection as well as carbon charge and injection based on evaluation of slag foaming via an acoustic sensor in EAF build an expert system of control rules for process management at Feralpi Lonato plant. For the used control rule parameters (e.g. limits for SOS and acoustic foaming index) there have been derived heuristics based on related KPIs for suitable auto-calibrations. For the auto-calibration of the SOS limits used within the control rules for oxygen injection (which were in the main focus for the EAF process at Feralpi Lonato), the heuristic uses information from the adapted sterile content in scrap.
At PTG as well as at Feralpi Lonato steel plant the installed tools support the operator in on-line monitoring and control of the EAF and secondary metallurgical ladle treatment processes, especially regarding electrical and chemical heating. Figure E gives an example of the newly installed HMI for online monitoring of the EAF processes at PTG steel plant. For support of end-point control of the heating process, the horizontal red line in the upper half indicates the target tapping temperature to be met by the actual temperature calculated cyclically by the EAF model.
Figure E: HMI for online monitoring and control of EAF processes at PTG steel plant
The installed least-squares fitting procedure for periodic adaption of the EAF model parameters mainly improves the mean model error (from mainly negative values to values around 0), whereas the standard deviation of the model error more or less is unaffected (cf. Figure F). The improvement of the mean model error results in an avoidance of systematic over- or underestimation of the melt temperature by about 5 – 10 K. Cases with systematic underestimation as shown in Figure F cause an overheating of the melt with related increase of
as well as negative effects on the lifetime of the furnace refractory. Cases with systematic overestimation of the melt temperature lead to need of
Figure F: Evolution of moving averages and standard deviations of errors in model temperatures at PTG with and without recalibration of parameters at the DC-EAF
The secondary metallurgical temperature model installed at PTG steel plant turned out to be already well calibrated and quite stable regarding the plant and process conditions. Thus, the batch-to-batch auto-calibration procedure based on the UKF approach has been tested after detuning of model parameters. This proved an automatic re-calibration of the model by the installed UKF procedure within about 20 heats resulting in reduced mean values and standard deviations of the model errors compared to the detuned cases.
The off-line application of the UKF approach for batch-to-batch auto-calibration of the CRM EAF model provided significant improvements of calculation accuracies (see Figure G). The mean error is decreased from 18,7 K to 3,5 K and the standard deviation from 58,8 K to 23,1 K.
Figure G: Correlation between calculated and measured temperature without (left) and with (right) auto-tuning of parameters for CRM EAF model
Thus, the on-line application of the CRM EAF model with batch-to-batch auto-calibration and thereby ensured improved model accuracies will lead to similar benefits as estimated above for the BFI EAF model applied at PTG steel plant.
For improved process monitoring and control of the EAF process at Feralpi Lonato steel plant, the auto-calibration of sterile content in scrap has been identified as one of the most important components. A moving average adaption of this parameter yields improved results for mass balance calculations including slag oxidation status (SOS) used for control of oxygen injection. Figure H gives an example for monitoring of the auto-calibrated sterile content of scrap and the related steel weight error.
Figure H: Monitoring of auto-calibrated sterile content of scrap and related steel weight error
The SOS based expert rules for on-line control of oxygen injection during refining in EAF lead to avoidance of overoxidation with reduced consumptions of electrical energy and oxygen and increased metallic yield. The on average achieved improvements at Feralpi Lonato plant comprise
Furthermore, the rules for alerts regarding arrival temperatures in LF and CC based on the installed temperature model for ladle treatment at Feralpi Lonato plant with adapted parameters have been proven to support the operator decisions for temperature control along the whole steelmaking route.
Reuse of slags from integrated steelmaking
In Europe 2016 steelmaking slags (SMS) amount to 18.4 Mio t/a, of those 10.4 Mio t/a are generated through BOF steelmaking. The majority of slags are used in road construction (46,0 %). Internal recycling for metallurgical use amounts to 15,3 % of the SMS. Unfortunately landfilling already makes up the third biggest share of life cycle destinations. This amount is prone to increase as future EU regulations will cause many SMS not to be permitted for use in road construction. Under the pretext of circular economy, it is desirable to increase internal recycling. That however is limited by the phosphorus content in the slag, due to the deterioration of material properties that would be caused by the phosphorus in steel. SLAGREUS, thus aims to increase internal recycling of primary BOF slag by generation of a high Fe- and low P-slag fraction ready for sintering or direct use in BF and a fraction containing high amounts of Ca and possible free lime for cement production.
This project receives funding from the Research Fund for Coal and Steel under grant agreement No. 847260. The project has started June 1st of 2019 and is set to be concluded on December 1st of 2022.
The research partners involved in the project are:
|VDEh – Betriebsforschungsinstitut GmbH (BFI)|
|Voestalpine Stahl GmbH (voestalpine)|
|K1-MET GmbH (K1-MET)|
|Institut für Baustoff-Forschung e.V. (FEhS)|
|Oulun Yliopisto (Uni Oulu)|
In order to achieve the goal of saving natural resources and reduce landfilling the amount of internally recycled SMS must be increased. It is therefore necessary to develop a new BOF-slag treatment process that allows for the slag to be divided into a fraction of high iron and low phosphorus content and a fraction of high calcium and phosphorus content. The Fe-rich/P-poor fraction will be tested for metallurgical re-use in sinter plants. The Ca-/P-rich fraction will be evaluated as a cement additive, as well as its use in lime fertilizers.
The additional objective of the project is the development of an off-line prediction tool for mass and energy balances of the recycling process, thereby providing information about expected quality and quantities of the slag fractions. The prediction tool will be based on the separation efficiency and specific energy demands of the individual unit operations within the process.
The new process concept is divided into two phases. A primary liquid treatment and secondary solid treatment.
During primary liquid the BOF-slag is slowly cooled to allow for large calcium-silicate crystals to form and segregate to the top of the crucible. The liquid Fe-enriched part is then recirculated into the next slag melt. This facilitates segregation. The obtained calcium-silicate rich phase can already be used as a test material for addition into cement. The iron enriched fraction is slowly cooled to generate large grain sizes, which benefits the secondary solid treatment.
The secondary solid treatment only focusses on the iron enriched fraction obtained from the primary liquid treatment. The first unit operation is the microwave heating of the slag, improving liberation of the individual mineral phases by generating thermally induced tension within the particles. The slag is than ground which the goal to complete phase liberation. The last step of the solid treatment consists of dry magnetic separation, after which the final Fe-rich/P-poor fraction will be separated from the Ca-/P-rich fraction.
During the project the process concept will be implemented and investigated at laboratory and pilot scale. The concept will also be tested on a small industrial scale. During each stage the processing parameters will be evaluated and will contribute to the development of the prediction tool.
After investigation into grain size distribution and composition via SEM, XRD and XRF of BOF-slag samples, it can be stated that the slow cooling of the slag has the predicted and desired effect of creating large crystal grains with complementary distribution of iron in some phases and phosphorus in other phases. This can be observed in the fluorescence maps depicted in the images below. Iron is marked blue and phosphorous is marked white.
That indicates, if the mineral phases can be separated, so can iron and phosphorous.
Minimise sinter degradation between sinter plant and blast furnace exploiting embedded real-time analytics (MinSiDeg) project abstract
Sinter with high and consistent quality, produced with low costs and emissions is very important for iron production. Transport and storage degrade sinter quality, generating fines and segregation effects.
Conventional sinter quality monitoring is insufficient: Slow and expensive. Consequently, the impact of sinter quality on daily BF operation is extremely intransparent.
In MinSiDeg, new transfer systems and procedures will minimise degradation during transfer to save return fines and stabilise particle size distribution.
New on-line measurements will be established, combined and exploited with Big Data technologies. This break-through in continuous quality monitoring will enable combined optimisation of sinter plant and blast furnace.
Major objective of the project MinSiDeg is to clearly decrease costs and environmental impact of sinter plants and blast furnaces. To achieve this, the sinter quality will be optimised along the production chain improving both, sinter plant and blast furnace working.
The following general technical objectives are defined:
MinSiDeg will realise the objectives by 3 main approaches (cf. Figure 1):
Figure 1: Main approaches within the MinSiDeg concept.
MinSiDeg research approach
The project work will be organised within 5 technical work packages:
The involved partners in this research project are
|thyssenkrupp Steel Europe AG|
|voestalpine Stahl GmbH|
|DK Recycling und Roheisen GmbH|
|The project leading to this application has received funding from the Research Fund for Coal and Steel under grant agreement No. 847334.|
Project duration: 1 July 2019 – 31 December 2022 (42 months)
Thermal and fluid-mechanical conditions in continuous casting moulds are only roughly known although highly relevant for the product quality. Manual process control is difficult due to the great number of influencing factors. Therefore, the aim of the research is the digitalisation and optimised control of continuous casting machines. Large data streams will considered online and assist the caster operators with a real-time support system. This system will provide suggestions for an optimised process control in real-time. It will be developed with application of new measuring techniques and representation of the casting machine by a digital twin.
The kick-off-meeting for the RFCS project “Embedded real-time analysis of continuous casting for machine-supported quality optimisation” (RealTimeCastSupport) took place on 1st and 2nd of October 2019 at premises of the coordinator BFI.
|AG der Dillinger Hüttenwerke|
|voestalpine Stahl GmbH|
|Materials Processing Institute (MPI)|
|Minkon SP ZOO|
The main objective of the proposed research project is:
The main objective is accompanied by several sub-objectives which can be assigned to the already mentioned main components of the research project:
Online monitoring of tundish and mould with implementation of new measuring techniques
Exploitation of various CC data and surface inspection to predict reliability of steel production
Advanced CC process control in real-time offering machine supported decisions
Online monitoring of tundish and mould with implementation of new measuring techniques
|Available measurement techniques|
An important research approach of this project is the simultaneous temperature measurements at different positions in tundish as well as in the mould and the monitoring of the casting powder coverage. This will provide a deeper insight of the conditions in the casting machine depending on time, i.e. transient conditions like ladle or tundish changes can be analysed in detail. The results can then be connected to quality information, i.e. hard spots appearance on heavy plates as well as sliver appearance on cold-rolled strips. The online application of the new measurement technologies FOTS and DynTemp® for temporally high resolving temperature is scheduled as well as the implementation of IR-based 2D casting powder monitoring system. The figure below illustrates the availability and position of the utilised measuring techniques.
Additionally, already available measurements, analysis and online modelling results systems will be utilised for the real-time machine support system:
Exploitation of various CC data and surface inspection to predict reliability of steel production
A self-evident element of this project component is the material tracking and the synchronisation of the available data streams. It has to be ensured that the quality information, i.e. hard spots and sliver occurrence, can be assigned to the corresponding casting conditions. But the casting conditions are not only valid for a certain time. They were taken at different positions, i.e. measurements with regard to the determined product quality have to be taken at different times, e.g. melt temperature in the tundish and in the mould, casting powder cover and copper plate temperatures. They have to be synchronised knowing well that different techniques show different idleness, e.g. temperature measurements in the copper plates react slower on melt temperature changes than the DynTemp® measurements. Material tracking algorithms are already available at the steel plants of the industrial partners. They will be used in the frame of the research project. Synchronisation of the measured data will be worked out in the frame of the comprehensive statistical analysis.
For the analysis and assessment of the mentioned data different methods from Data Mining and Big Data analytics will be used. For the computations with the 3D digital twin the analysis of influencing factors of casting is necessary in order to find the target parameter, e.g. the occurrence of hard spots. Therefore, a common analysis of the casting parameters, i.e. the various temperature measurements in tundish and mould and the results of image processing, will be executed by means of Data Mining methods in a first step. Several methods like Decision Tree analysis, artificial neural networks, e.g. Self Organising Map or Deep Learning methods, and others will be applied to detect relationships between the input parameters and the target one. The aim is to identify those inputs – or derived features- which are influencing mainly the target parameter. By the derived subset of input values a digital twin of the casting machine, i.e. a transient CFD model of the considered casting machine, will be developed in order to estimate the impact of altered parameters on product quality features. The findings will be integrated in the real-time support system by the definition of a set of rules describing possible countermeasures. The real-time support system will provide information about possible critical process conditions causing defects and will support operators to find appropriate countermeasures, i.e. it supports the decision making.
Based on these findings measures for an improved thermal and fluid-mechanical process control will be worked out and their potential for thermal and fluid-mechanical process control will be checked with the digital twin. These developed countermeasures will be tools which strengthen the options for real-time process control in the machine support system.
Advanced CC process control in real-time offering machine supported decisions
The chart below shows the organisation of the scheduled real-time support system with the different modules contributing to this system. Comprehensive temperature measurements in tundish and mould as well as the monitoring of the casting powder cover provide the basis for this approach. On the one hand, these data will be utilised for the offline statistical data analysis aiming at an assessment of the casting process and correlations with the corresponding product quality. On the other hand, measurements and monitoring will provide an online basis for the real-time support system. Here the defined rules for an advanced process control will be evaluated in real-time and the status of the casting machine will be judged, e.g. realised as a traffic light.
The project leading to this application has received funding from the Research Fund for Coal and Steel under grant agreement No. 847334. On 1./2. October 2019 was the kick-off meeting in the BFI. http://www.bfi.de/en/2019/10/16/kick-off-meeting-realtimecastsupport-october-1st-2nd-in-dusseldorf/
Exploitation of Projects for Low-Carbon Future Steel Industry
LowCarbonFuture project abstract
The project “LowCarbonFuture” has the objective to collect, summarize and evaluate research projects and knowledge dealing with CO2-mitigation in iron and steelmaking.
As final result, LowCarbonFuture will generate a roadmap stating research needs, requirements and boundary conditions for breakthrough technologies and a new CO2 lean steel production to guide the EU steel industry towards the world’s climate contract and the EU climate goals, e.g. by implementing the key findings in the strategic research agenda of the European Steel Technology Platform (ESTEP). Furthermore, “LowCarbonFuture” will contribute to an update of the steel roadmap for a low carbon Europe 2050 and the current BIG-Scale initiative of EUROFER.
LowCarbonFuture initial situation
According to the steel roadmap edited by the European Steel Association (EUROFER), CO2 emission must be decreased by at least 80 % until 2050 (based on 1990’s level).
Only by means of incremental improvement of ironmaking and steelmaking processes the reduction target cannot be reached, since European production routes already perform at their physical thermodynamic limits (black and blue curves in Figure). A complex mix of actions are necessary (curves orange, red and brown in Figure) to reach the ambitious reduction target.
LowCarbonFuture technological pathways
Current pan-European research is focused on the two main pathways Carbon Direct Avoidance (CDA), and Smart Carbon Usage (SCU). SCU is further divided into the pathways Process Integration (PI) and Carbon Capture, Storage and Usage (CCU).
CDA means the production of steel without direct release of carbon emissions based on hydrogen and electricity. Regarding the energy supply, steel production is shifted from carbonaceous sources to hydrogen based sources with electricity from renewable energies. The pathway PI covers the existing steelmaking routes (BF / BOF and DRI / EAF) using fossil fuels (coal, natural gas, etc.) and how these processes must be adopted to release less CO2. Carbon Capture and Usage (CCU) covers the usage of CO2 i.e. all the options for utilizing the CO and CO2 in steel plant gases or fumes as raw material for production of/integration into valuable products.
The involved Partners in the research project are:
|Centre de Recherches Metallurgiques (CRM)|
|Rina Consulting Centro Sviluppo Materiali S.P.A. (CSM)|
|K1-MET GmbH (K1-MET)|
|Swerim AB (SWERIM)|
This project receives funding from the Research Fund for Coal and Steel under grant agreement No. 800643.
The main objectives of this project are:
Further information and news of the LowCarbonFuture project can be found on www.lowcarbonfuture.eu/
Model-based optimisation for efficient use of resources and energy.
Working points in the project
The project started at October 1st 2017 and ends at September 30st 2021. Involved partners in the research are:
|GRIPS Industrial IT Solutions GmbH|
|OPTIMIZACION ORIENTADA A LA SOSTENIBILIDAD SL|
|Maschinenfabrik Liezen und Gießerei GmbH|
|OUTOKUMPU STAINLESS OY|
|SSAB EUROPE OY|
|Teknologian tutkimuskeskus VTT OY|
Model-based offline and real-time optimisation tools for the whole process route to increase overall energy and resource efficiency as well as product quality in production of high-strength carbon steels, stainless steels and cast steels.
The research has received funding from the European Commission, funding reference Horizon 2020 (H2020) / SPIRE-07-2017 / 768652.
Cyber-Physical Production Optimization Systems for Long Production Factories
Cyber-POS project abstract and objectives
Production technology in steel industry has reached a level that significant improvements can only be reached by through process optimization strategies instead of improving each process step separately. Therefore the connection of suitable technological models to describe process and product behavior, methods to find solutions for typical multi-criterial decisions and a strong communication between involved plants becomes mandatory. Cyber-POS will develop a virtual simulation platform for the design of cyber-physical production optimization systems (CPPS) for long production facilities with special emphasis to thermal evolution and related material quality, leading to reduced energy consumption, shortened production time and improved product quality.
The main objectives within this project are:
This is achieved by applying the developed software and methods for the specific use cases. This implies the following sub-objectives:
The project started at July 1st 2016 and ends at December 31th 2019. Involved partners in the research are:
|Arcelor Mittal España|
|Scuola Superiore Sant’Anna di Studi Universitari e di Perfezionamento|
Cyber-POS project expected industrial impacts
The research has received funding from the European Union’s Research fund for Coal and Steel (RFCS) under grant agreement No. 709669.
The main motivation for introducing the methods of cyber-physical production optimization is essentially to preserve the economic performance and safety level in spite of faults and process changes that may occur over time. The CPS platform to be developed can be regarded as an assistance system that will support plant personnel/operator decisions, and thus can contribute to the improvement of working conditions. All involved processes can actively communicate with each other, know their field of activity and production conditions. The optimizations made are also more tailored to the human workforce.
Higher maintainability, reliability and efficiency of long production factories through cyber-physical production optimization will lead to improved product quality, reduced maintenance costs and decreased material and energy consumption. This will have a positive impact on preservation of natural resources, energy and environment. Needless to say, reducing energy consumption leads to reduced CO2 emissions.
At the two involved plants of ArcelorMittal España and Mannstaedt, the developed concept will be installed as assistance system and tested in the process route reheating, hot rolling and cooling. This leads to increased flexibility of process chain, higher productivity, better disturbance management and energy savings.
Real Time Monitoring of coal composition in closed systems for fast process control
RemoCoal project abstract
Nowadays for competitive hot metal production at a Blast furnace it is necessary to realize a high pulverised coal (PC) injection rate at a minimised coke rate. But actually there is a lack of real time analytical technologies to obtain reliable short time information of the actual composition of pulverized coal blend which is injected into the blast furnace (BF). A real time analysis of the pulverised coal blend opens up the opportunity to detect unexpected or prompt deviation in coal blend composition. It enables to run an optimized total BF fuel rate, a reduction of fuel cost for hot metal production and subsequently decreasing CO2 emissions.
Within the project the Pulsed Fast and Thermal Neutron Analysis (PFTNA) technology designed as borehole logging tool will be modified and applied in a closed silo of a pulverized coal injection (PCI) system. BF trials for real-time analysis of coal composition to adjust the coal injection rate near time will be performed.
The PFTNA-technique takes advantage of a switchable pulsed neutron generator for emission of fast and thermal neutrons and a gamma ray detector which record the characteristic gamma photons generated by interaction of the emitted neutrons with the nuclei of the surrounding coal material. It delivers characteristic spectra as basis for determination of the PC composition.
Additional the real time spectra will be processed by fingerprint analysis software (pattern recognition). The analysis is based on statistical data evaluation of the gamma spectra and delivers the operator principle parameter of the PC for Blast furnace optimization.
The involved Partners in the research project are:
|VDEh – Betriebsforschungsinstitut GmbH|
|Malvern Panalytical GmbH|
|thyssenkrupp Steel Europe AG|
This project receives funding from the Research Fund for Coal and Steel under grant agreement No. 754 200
The main objective of this project is to demonstrate the high benefit of the real time analysis of coal composition for industrial application in better adjusting/controlling the pulverised coal injection rate and improve the production process.
The implementation of the PFTNA technology and the finger print analysis software enables to:
The new technology shall be demonstrated at the pulverized coal injection plant of a BF at tk SE. Finally, a concept will be set up for the implementation of the PFTNA technology and the real-time data evaluation at European blast furnaces.
Remocoal research approach
The development of the online monitoring systems in RemoCoal will be achieved in four major steps. An overview of the concept is illustrated in the following figure:
Recent results of the RFCS research project PowGETEG (Power generation from hot waste gases using thermoelectrics)
PowGETEG project abstract
Industries involve a huge amount of energy consumption. A considerable amount of this energy is lost and escapes to ambient as waste heat. Energy recovery from industrial waste-heat streams attracts interest for commercial and strategic reasons. Main drivers are international competition and technological opportunities, combined with geopolitical issues such as security of energy supply, energy consumption and greenhouse gas emission. In recent years, numerous ideas have been suggested either for better process integration, reuse in other settings, or for power generation. For an efficient use of waste heat generally following order is essential:
In the iron and steel industry the points 1 to 3 are usually state of the art. Thermoelectric (TE) devices have the ability of directly convert waste heat into electricity and can be located under point 4.
TE materials are semiconductors which exhibit a strong relationship between a current flow in the material and the passage of heat through the material. This is due to the Seebeck effect. The Seebeck effect shows itself as the generation of electrical power from the semiconductor when opposite ends of a piece of the material are subjected to hot and cold temperatures respectively. TE modules consist of arrays of N and P type semiconductors in which electrical energy can be produced. TE systems have well known advantages: no moving parts, simple configuration and long-run unattended operation for thousands of hours. Additionally, they are scalable and do not release any pollutant to the environment during operation. Hence, they could be suited for many applications at different scales. Proved applications of thermoelectric power production are in the Aero and Space industry and for power supply in remote areas e.g. at pipelines, on offshore platforms or in nature protection areas. Until now waste heat recovery from industrial plants by TE devices is just demonstrated in research projects in prototype scale applications.
The RFCS PowGETEG research project aims to investigate the possibilities of TE power generation using industrial gaseous waste heat at temperatures well above 550 °C in order to verify the techno-economic feasibility of TE systems for industrial scale waste heat utilization.
The project started at July 1st 2015 and ends at December 31st 2018. Involved partners in the research are
|University of Glasgow|
|thyssenkrupp Steel Europe AG|
The research has received funding from the European Union’s Research fund for Coal and Steel (RFCS) research programme under grant agreement No°RFSR-CT-2015-00028.
Waste heat recovery by TE systems in industrial scale is not known until now. Just a few research projects investigate TE waste heat recovery, mainly in low temperature range with common BI2Te3 modules. Knowledge and studies about high temperature waste heat recovery by thermoelectrics in industrial plants and industrial scale are rare.
Aim of the project is to develop a TE demonstrator with a power output of 1 kWel for utilization of high temperature industrial waste gases with temperatures well above 550°C. The demonstrator will be tested in an industrial environment for several months to determine the techno-economic feasibility of such a system and to make statements about the possibility to use the technology in non-iron and steel industries.
PowGETEG research approach
Main aim is the long-term testing of a newly developed TE demonstrator in an industrial environment. Thus, several waste heat sources of an integrated steel mill will be studied, supported by both tests and data evaluation to determine their suitability for such a long-term test.
Since the TE system will be installed in the waste gas of an iron and steel manufacturing process, advanced components, materials and solutions need to be integrated in the TE system and the electrical power subsystem. These requirements are determined by the high temperature level at which TE power generation will now be applied and the nature of such waste gases, that are produced when combusting iron and steel process gases. For that reason surface coatings for antifouling will be investigated to protect the heat exchanger of the TE system from damages.
To optimize the performance and power output of the TE system a tailor made power converter and new MPPT (Maximum Power Point Tracking) algorithm will be developed. The goal of the MPPT algorithm is to set the TE system to operate at its optimum power output according to the temperature conditions.
By testing a bench scale unit in the laboratory under near-service conditions, which will be able to produce about 200 Wel, conclusions can be drawn about the requirements to process control, power conversion, heat exchanger design and the construction that supports the TE system in the waste heat stream.
Based on the results of the bench scale test a 1 kWel demonstrator will be developed and tested at the selected industrial plant for several months. The results will then be used to study the techno-economic feasibility of implementing TE systems in high temperature waste gases. This includes a comparison with other steam based power producing technologies and an extrapolation of the research results to other industries.
PowGETEG recent results
Main results obtained until now are:
A suitable waste heat source at TKSE steel plant was selected and the connection for the demonstrator installed.
A thermoelectric cartridge with an expected power output of 250 W was assembled and tested in the laboratory under near-service conditions.
A power conversion system was developed and assembled. A new MPPT algorithm was designed with an increased power output of 3.7 % compared to other MPPT algorithms.
Coatings for antifouling were investigated and suitable coatings selected
Recent results of RFCS DEPREX research project – Early detection and prevention ot tuyere damaging conditions for extension of tuyere life time at blast furnaces
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Up to now the damage of a blast furnace tuyere is an unpredictable incident during usual blast furnace operation, which happens in average between 30 to 120 times a year. Each single tuyere damage effect a stoppage of the whole blast furnace of several hours for repair. Those unplanned stoppages caused by tuyere damage effect:
Although BF operators and R&D institutes have done a lot of effort analysing the tuyere damages and trying to find the reasons for those incidents there are still major gaps what to do or avoid for lowering tuyere damage incidents at BF operation. The main difficulty up to now was the “singular” character of the incidents due to local thermal overload and the massive destruction effect within short time, which has led to an acceptance of those damages as usual in the past. Consequently, no operational tools are available, yet, to solve the problem.
The RFCS DEPREX research project aims to develop an operational online control system for early detection and prevention of tuyere damaging conditions in order to decrease the frequency of unplanned BF stoppages for significant reduction of energy consumption and costs in BF operation.
The damage of a blast furnace tuyere is an unpredictable incident in blast furnace operation. Each single tuyere damage effect a stoppage of the whole blast furnace of about two hours up to eight hours for repair. Although, the hot blast is stopped and no hot metal is produced, coke is consumed and additional coke has to be charged. Energy is spent without any benefit.
The additional energy caused by a BF stoppage due to tuyere damage has been estimated roughly to about 1.600 TJ each year for German BF only. The estimation implied a damage frequency of 45 damages per blast furnace and year. Assuming the same tuyere damage frequency for blast furnaces in EU 28 the useless energy consumption results of more than 6.000 TJ. Doubling the extension of BF tuyere life time gives a benefit of 3000 TJ. Therefore reduction of tuyere damage frequency is an important aim to the sustainable energy use and reduction of costs strengthening the competitiveness of the European iron and steel industry.
The aim of the planned RFCS project is the development of an online BF tuyere damage risk assessment system for early detection and prevention of tuyere damaging conditions in order to decrease the frequency of unplanned BF stoppages. The decreasing number of unplanned blast furnace stoppages due to tuyere damages enables a significant reduction of energy consumption and costs in blast furnace operation. Furthermore, it decreases the risk for the occupational health due to e. g. contact of blast furnace staff with toxic CO containing gas and hot metal during exchange of damaged tuyeres. Therefore, each prevented tuyere damage helps to increase safety of BF staff.
Consequently, the proposed project contributes to the RFCS programme objectives (Council Decision 2008/376/EC).
To reduce the frequency of unplanned stoppages due to tuyere damages an innovative BF tuyere damage protection approach is developed with the project DEPREX. The key idea of this new approach is to detect early indications for BF tuyere damaging conditions before the tuyere damaging process has started and to prevent those conditions with suitable countermeasures in BF operation. Thus, the BF tuyere life time will be extended. The new integrated DEPREX approach is shown schematically in the figure below.
Additional knowledge about BF tuyere damage mechanism and weak spots / areas at tuyeres is generated by advanced analysis of the degradation of BF tuyere material properties over the life time of such components. Up to now metallurgical and thermo chemical investigations have only been carried out at damaged tuyeres. The chronology of material properties of BF tuyeres “from cradle to grave” has never been investigated before and is expected to give important additional information. The additional knowledge about tuyere damaging mechanisms is one key component in the development of the new online BF tuyere damage risk assessment system.
In order to get the necessary thermal data from the BF tuyere area new operational BF measuring tuyeres (MT) with advanced fibre optical temperature measurement device will be developed. The BF measuring tuyeres with fibre optical temperature measurement, generates important information concerning the thermal conditions in the BF hearth for the BF tuyere damage risk assessment system.
The new operational BF tuyere optical monitoring system (OMS) is used for monitoring of the BF tuyere and detection of tuyere damaging conditions. The system generates additional input for the new BF tuyere damage protection system. The new technology can be used as trigger for countermeasures at an early stage. Consequently, the advanced optical monitoring system brings an added value to the early detection of abnormal tuyere operation conditions effecting tuyere damages.
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The data and information generated with the new operational BF tuyere monitoring systems (MT & OMS) together with operational data of the blast furnace are concluded, analysed and processed in the model-based online tuyere damage risk assessment system. The aim is an early detection and prevention of BF tuyere damaging conditions with appropriate counteractions of the BF operators.
The basic idea of this new online BF tuyere damage risk assessment system is, first, to provide new operational BF tuyere monitoring systems improving and combing the prototype measuring tuyeres and the tuyere optical control system established in a previous project. Second, the measuring data will be correlated with operational data of the blast furnace. The results will be exploited for industrial online application in a model based online BF tuyere damage risk assessment system. The new BF tuyere damage protection system is composed of the following modules/ components:
The overall aim of the DEPREX RFCS research project is the early detection and prevention of tuyere damaging conditions for the extension of BF tuyere life time. The decrease of the frequency of unplanned blast furnace stoppages due to tuyere damages effect a significant reduction of energy consumption and costs in blast furnace operation, contributing to the RFCS programme objectives and strengthening the competition of ironmaking in Europe.
|thyssenkrupp Steel Europe AG|
|voestalpine Stahl GmbH|
|ISD Dunaferr Co. Ltd|
|Furol Co. Ltd|
|The project leading to this application has received funding from the Research Fund for Coal and Steel under grant agreement No 709424.|