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  • 1.
    Al-Saadi, Munir
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Sandberg, Fredrik
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Stefan
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Microstructure characterisation in alloy 8252018Konferensbidrag (Refereegranskat)
  • 2.
    Al-Saadi, Munir
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Sandberg, Fredrik
    Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression2018Ingår i: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October, 2018, artikel-id 114Konferensbidrag (Refereegranskat)
  • 3.
    Al-Saadi, Munir
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi. R&D, AB Sandvik Materials Technology, SE-811 81Sandviken, Sweden..
    Sandberg, Fredrik
    R&D, AB Sandvik Materials Technology, SE-811 81Sandviken, Sweden..
    Hulme-Smith, Christopher
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    A study of the static recrystallization behaviour of cast Alloy 825 after hot-compressions2019Ingår i: Journal of Physics: Conference Series, 2019, Vol. 1270Konferensbidrag (Refereegranskat)
    Abstract [en]

    The static recrystallization behaviour of a columnar and equiaxed Alloy 825 material was studied on a Gleeble-3800 thermo-simulator by single-hit compression experiments. Deformation temperatures of 1000-1200 °C, a strain of up to 0.8, a strain rate of 1s-1, and relaxation times of 30, 180, and 300 s were selected as the deformation conditions to investigate the effects of the deformation parameters on the SRX behaviour. Furthermore, the influences of the initial grain structures on the SRX behaviors were studied. The microstructural evolution was studied using optical microscopy and EBSD. The EBSD measurements showed a relaxation time of 95 % for fractional recrystallization grains, 𝑡95, in both structures, was less than 30 seconds at the deformation temperatures 1100 °C and 1200 °C. However, fewer than 95% of recrystallized grains recrystallized when the deformation temperature was lowered to 1000 °C. From the grain-boundary misorientation distribution in statically recrystallized samples, the fraction of high-angle grain boundaries decreased with an increasing deformation temperature from 1000 °C to 1200 °C for a given relaxation time. This was attributed to grain coarsening

  • 4.
    Arzpeyma, Niloofar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Mathematical Modeling of Postcombustion in an Electric Arc Furnace (EAF)2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 5, artikel-id 547Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Numerical modeling was used to study the capability of postcombustion in an electric arc furnace (EAF) equipped with virtual lance burners. The CO flow rate at the molten bath surface was estimated using the off-gas data obtained close to the outlet of an EAF. Then, the effect of the secondary oxygen flow rate on postcombustion was studied. The results show a CO flow rate of 0.6 kgs(-1) and 0.8 kgs(-1) for operation modes of burner and burner + lancing. Increase of the secondary oxygen flow rates of 60% and 70% result in 17% and 7% increase in the postcombustion ratio (PCR) for the burner and burner lancing modes, respectively.

  • 5.
    Bai, Haitong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Numerical study of an application of a divergent reverse TurboSwirl nozzle in the billet continuous casting process2019Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 46, nr 2, s. 148-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The swirling flow has widely been investigated for liquid steel flowing in the continuous casting process. In this paper, a new design of the submerged entry nozzle (SEN) is applied by using a reverse TurboSwirl device with a divergent nozzle. This divergent reverse TurboSwirl nozzle (DRTSN) is shown to gain a more beneficial flow pattern compared to the straight nozzle. A stronger swirling flow can be obtained at the SEN outlet, which leads to a calmer flow field and an appropriately active meniscus flow that could improve the heat and mass transfer near the meniscus. The swirl number in the SEN is independent of the casting speed, while a lower casting speed yields a lower maximum wall shear stress. The DRTSN is connected to the tundish by an elbow and a horizontal runner. A longer horizontal runner supplies a more uniform velocity profile and a more symmetrical flow pattern.

  • 6.
    Bai, Haitong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Ni, Peiyuan
    Northeastern Univ, Sch Met, Key Lab Ecol Met Multimet Intergrown Ores, Educ Minist, Shenyang 110819, Liaoning, Peoples R China.;Osaka Univ, Grad Sch Engn, Dept Mat & Mfg Sci, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Zhang, Tingan
    Northeastern Univ, Sch Met, Key Lab Ecol Met Multimet Intergrown Ores, Educ Minist, Shenyang 110819, Liaoning, Peoples R China..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Effect of swirling flow tundish submerged entry nozzle outlet design on multiphase flow and heat transfer in mould2019Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Effect of a swirling flow SEN (submerged entry nozzle) outlet design on the multiphase flow and heat transfer in a mould was investigated by using numerical simulation. It was found that different SEN outlet designs could form different flow patterns and temperature distributions on the upper of the mould. The enlarged outlet SEN design had an effect to decrease the horizontal velocity of liquid steel flowing out the SEN outlet, reducing the steel flow velocity towards the solidification front. Although a higher velocity was found near the slag/steel interface with the enlarged outlet SEN, but the turbulent kinetic energy was lower. The reason was that less circulation flows were formed in the region of the mould top. The weak horizontal flow towards the solidification front with the enlarged outlet SEN induced lower wall shear stresses, at the same time it also formed a lower temperature distribution near the solidified shell.

  • 7.
    Bölke, Kristofer
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Andersson, Nils A. I.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Imris, Matej
    ScanArc Plasma Technol AB, SE-81321 Hofors, Sweden..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 1, artikel-id 101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    IronArc is a newly developed technology and an emerging future process for pig iron production. The long-term goal with this technology is to reduce the CO2 emissions and energy consumption compared to existing technologies. The production rate of this process is dependent on the stirring, which was investigated in the pilot plant process by measuring the mixing time in the slag bath. Moreover, slag investigations were done both based on light optical microscope studies as well as by Thermo-Calc calculations in order to determine the phases of the slag during operation. This was done because the viscosity (which is another important parameter) is dependent on the liquid and solid fractions of the slag. The overall results show that it was possible to determine the mixing time by means of the addition of a tracer (MnO2 powder) to the slag. The mixing time for the trials showed that the slag was homogenized after seconds. For two of the trials, homogenization had already been reached in the second sample after tracer addition, which means <= 8 s. The phase analysis from the slag indicated that the slag is in a liquid state during the operation of the process.

  • 8.
    Bölke, Kristofer
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Imris, Matej
    ScanArc Plasma Technol AB, SE-81321 Hofors, Sweden..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Importance of the Penetration Depth and Mixing in the IRONARC Process2018Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 58, nr 7, s. 1210-1217Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the most important parameters for gas injection into liquid baths is the penetration depth of the gas into the bath. This is due to that it strongly influences the flow structure and hence the stirring and plume behavior in metallurgical processes. The IRONARC process is a new energy efficient process for reduction of iron oxide to produce pig iron. The future goal is to continuously scale up the process to an industrial scale from the current pilot scale. In this process, gas is injected horizontally through a submerged nozzle into a slag bath. Hence, the penetration depth is of great importance since it greatly affect several parameters in this process. Moreover, this information is essential when scaling up the reactor from a pilot scale to an industrial scale. In this work, the penetration depth of gas injection into water in a small scale side blown converter was studied numerically. Two different approaches with different multiphase models were tested, namely the Volume of Fluid (VOF) model and Eulerian multiphase model (EE). The penetration depth could be accurately determined for both numerical models, with a small expected deviation of 13.9% from the physical experiment results. Also, the simulation time was shorter for the Eulerian multiphase model. The penetration depth was then determined for the IRONARC pilot plant process. The results show that the plume is detached from the nozzle wall, which in turn results in a better energy usage of the gas along with a small refractory wear.

  • 9.
    Bölke, Kristofer
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ni, Peiyuan
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Swartling, Maria
    ScanArc Plasma Technol AB, SE-81321 Hofors, Sweden..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Physical Modeling Study on the Mixing in the New IronArc Process2018Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, nr 7, artikel-id 1700555Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    IronArc is a newly developed technology for pig iron production with the aim to reduce the CO2 emission and energy consumption, compared to a conventional blast furnace route. In order to understand the fluid flow and stirring in the IronArc reactor, water modeling experiments are performed. Specifically, a down scaled acrylic plastic model of the IronArc pilot plant reactor is used to investigate the mixing phenomena and gas penetration depth in the liquid bath. The mixing time is determined by measuring the conductivity in the bath, after a sodium chloride solution is added. Moreover, the penetration depth is determined by analyzing the pictures obtained during the experimental process by using both a video camera and a high speed camera. The results show that the bath movements are strong and that a circular movement of the surface is present. The mixing in the model for the flow rate of 282 NLmin(-1) is fast. Specifically, the average mixing times are 7.6 and 10.2s for a 95% and a 99% homogenization degree, respectively. This is 15% and 18% (per degree of homogenization) faster compared to the case when using 3 gas inlets and the same flow rate.

  • 10.
    Carlsson, Leo
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Samuelsson, Peter
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Predicting the Electrical Energy Consumption of Electric Arc Furnaces Using Statistical Modeling2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 9, artikel-id 959Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Statistical modeling, also known as machine learning, has gained increased attention in part due to the Industry 4.0 development. However, a review of the statistical models within the scope of steel processes has not previously been conducted. This paper reviews available statistical models in the literature predicting the Electrical Energy (EE) consumption of the Electric Arc Furnace (EAF). The aim was to structure published data and to bring clarity to the subject in light of challenges and considerations that are imposed by statistical models. These include data complexity and data treatment, model validation and error reporting, choice of input variables, and model transparency with respect to process metallurgy. A majority of the models are never tested on future heats, which essentially renders the models useless in a practical industrial setting. In addition, nonlinear models outperform linear models but lack transparency with regards to which input variables are influencing the EE consumption prediction. Some input variables that heavily influence the EE consumption are rarely used in the models. The scrap composition and additive materials are two such examples. These observed shortcomings have to be correctly addressed in future research applying statistical modeling on steel processes. Lastly, the paper provides three key recommendations for future research applying statistical modeling on steel processes.

  • 11.
    Carlsson, Leo
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Samuelsson, Peter
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär G.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Using statistical modeling to predict the electrical energy consumption of an electric arc furnace producing stainless steel2020Ingår i: Metals, ISSN 2075-4701, Vol. 10, nr 1, artikel-id 36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The non-linearity of the Electric Arc Furnace (EAF) process and the correlative behavior between the process variables impose challenges that have to be considered if one aims to create a statistical model that is relevant and useful in practice. In this regard, both the statistical modeling framework and the statistical tools used in the modeling pipeline must be selected with the aim of handling these challenges. To achieve this, a non-linear statistical modeling framework known as Artificial Neural Networks (ANN) has been used to predict the Electrical Energy (EE) consumption of an EAF producing stainless steel. The statistical tools Feature Importance (FI), Distance Correlation (dCor) and Kolmogorov–Smirnov (KS) tests are applied to investigate the most influencing input variables as well as reasons behind model performance differences when predicting the EE consumption on future heats. The performance, measured as kWh per heat, of the best model was comparable to the performance of the best model reported in the literature while requiring substantially fewer input variables.

  • 12.
    Davydenko, Arkadiy
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Glaser, Bjoern
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Direct Reduction of Fe, Ni and Cr from Oxides of Waste Products Used in Briquettes for Slag Foaming in EAF2019Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, nr 20, artikel-id 3434Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Environmental aspects and the sustainable manufacturing of steels require producers to pay more and more attention to the efficient utilization of materials and waste products during steelmaking. This study is focused on the evaluation of possibilities for the recovery of metals (such as Fe, Ni and Cr) from waste products used for slag foaming in the Electric Arc Furnace (EAF) process. Two types of industrial briquettes were produced by mixing mill-scale from the hot rolling of stainless steels with anthracite and pet-coke, respectively. Thereafter, an assessment of the metal reduction processes in briquettes at high temperatures (1500 degrees C) was made by using laboratory thermo-gravimetric reduction experiments in an argon atmosphere. The amounts of metal, slag and gas obtained from the briquettes were estimated. In addition, the velocity and time for the removal of metal droplets from the liquid slag depending on the size of the metal droplets was estimated. It was found that up to 97% of metal droplets can be removed from the slag during the first 30 min. Moreover, results showed that most of the Cr, Ni and Fe (up to 93-100%) can be reduced from oxides of these metals in briquettes at 1500 degrees C. Moreover, the anthracite and pet-coke in the investigated briquettes have similar reduction capabilities. It was found that up to 330 kg of Fe, 28 kg of Ni and 66 kg of Cr per ton of added briquettes can be recovered from waste products by the industrial application of those briquettes for slag foaming in EAF.

  • 13.
    De Colle, Mattia
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Gauffin, Alicia
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Renman, Agnieszka
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    The Use of High-Alloyed EAF Slag for the Neutralization of On-Site Produced Acidic Wastewater: The First Step Towards a Zero-Waste Stainless-Steel Production Process2019Ingår i: Applied Sciences, ISSN 2076-3417, Vol. 9, nr 19, artikel-id 3974Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recycling of steelmaking slags has well-established applications, such as their use in cement, asphalt, or fertilizer industries. Although in some cases, such as the electric arc furnace (EAF) high-alloyed stainless-steel production, the slag’s high metal content prevents its use in such applications. This forces companies to accumulate it as waste. Using concepts such dematerialization, waste management, industrial symbiosis, and circular economy, the article drafts a conceptual framework on the best route to solving the landfilling issue, aiming at a zero-waste process re-design. An experimental part follows, with an investigation of the use of landfill slag as a substitute of limestone for the neutralization of acidic wastewater, produced by the rinsing of steel after the pickling process. Neutralization of acidic wastewater with both lime and slag samples was performed with two different methods. Two out of four slag samples tested proved their possible use, reaching desired pH values compared to lime neutralizations. Moreover, the clean waters resulting from the neutralizations with the use of both lime and slag were tested. In terms of hazardous element concentrations, neutralization with slag yielded similar results to lime. The results of these trials show that slag is a potential substitute of lime for the neutralization of acidic wastewater.

  • 14.
    Du, Hongying
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Sundqvist, Olle
    Sandv Mat Technol AB, S-81181 Sandviken, Sweden..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 1, artikel-id 74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The focus of this study involved comparative investigations of non-metallic inclusions in 316L stainless steel bars without and with Ca treatments. The inclusions were extracted by using electrolytic extraction (EE). After that, the characteristics of the inclusions, such as morphology, size, number, and composition, were investigated by using a scanning electron microscope (SEM) in combination with an energy dispersive X-ray spectroscopy (EDS). The following four types of inclusions were observed in 316L steels: (1) Elongated MnS (Type I), (2) MnS with hard oxide cores (Type II), (3) Undeformed irregular oxides (Type III), and (4) Elongated oxides with a hard oxide core (Type IV). In the reference sample, only a small amount of the Type III oxides (Al2O3-MgO-MnO-TiOx) existed. However, in Ca-treated 316L steel, about 46% of the observed inclusions were oxide inclusions (Types III and IV) correlated to gehlenite and to a mixture of gehlenite and anorthite, which are favorable for the machinability of steel. Furthermore, untransformed oxide cores (Al2O3-MgO-MnO) were also found in the inclusions of Type IV. The mechanism leading to different morphologies of oxide inclusions is also discussed.

  • 15.
    Ghadamgahi, Mersedeh
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Ovako Sweden AB, Sweden.
    Olund, Patrik
    Ekman, Tomas
    Andersson, Nils
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A Comparative CFD Study on Simulating Flameless Oxy-Fuel Combustion in a Pilot-Scale Furnace2016Ingår i: Journal of Combustion, ISSN 2090-1968, E-ISSN 2090-1976, artikel-id 6735971Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current study presents a method to model the flameless oxy-fuel system, with a comparative approach, as well as validation of the predictions. The validation has been done by comparing the predicted results with previously published experimental results from a 200 kW pilot furnace. A suction pyrometer has been used to measure the local temperature and concentrations of CO, CO2, and O-2 at 24 different locations. A three-dimensional CFD model was developed and the validity of using different submodels describing turbulence and chemical reactions was evaluated. The standard k-epsilon model was compared with the realizable k-epsilon model for turbulence, while Probability Density Function (PDF) with either chemical equilibrium or the Steady Laminar Flamelet Model (SLFM) was evaluated for combustion. Radiation was described using a Discrete Ordinates Model (DOM) with weighted-sum-of-grey-gases model (WSGGM). The smallest deviation between predictions and experiments for temperature (1.2%) was found using the realizable k-epsilon model and the SLFM. This improvement affects the prediction of gaseous species as well since the deviation between predictions and experiments for CO2 volume percentages decreased from 6% to 1.5%. This provides a recommendation for model selections in further studies on flameless oxy-fuel combustion.

  • 16.
    Ghadamgahi, Mersedeh
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Ovako AB, Stockholm, Sweden..
    Olund, Patrik
    Ovako AB, Stockholm, Sweden..
    Ekman, Tomas
    AGA AB, Linde Grp, Lidingo, Sweden..
    Andersson, Nils
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Numerical and experimental study on flameless oxy-fuel combustion in a pilot-scale and a real-size industrial furnace2018Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 141, s. 788-797Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previously validated CFD model was used to simulate the flameless oxy-fuel combustion in a pilot-scale furnace and a full-scale soaking pit furnace. The CFD predictions for temperature were compared with experimental data measured by shielded S-type thermocouples for both furnaces. The results indicate the validity of using shielded S-type thermocouples for temperature measurement, although use of the suction pyrometers renders more accurate results. Afterwards, the validation of previously proposed CFD model for simulating the flamaless oxy-fuel combustion is investigated in a full-scale soaking pit furnace in the production route of steel bars. The validation has been done by comparing the predicted temperatures with experimental data obtained by using S-type thermocouples. For both pilot-scale and full-scale furnaces a three dimensional CFD model with realizable k-epsilon, Probability Density Function (PDF) with Steady Laminar Flamelet Model (SLFM) and Discrete Ordinates Model (DOM) with Sum of The Weighted Gray Gases Model (SGGWM) for simulating turbulence, combustion and radiation was performed. The predicted temperature results show a good agreement with measured data from shielded S-type thermocouples for pilot-scale and full-scale furnace. More specifically the maximum deviation was 3.3% and 9.95% respectively. Afterwards, the simulation results on the full-scale furnace have been used to investigate the non-uniformity of temperature distribution inside the chamber. 

  • 17.
    Han, Tong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ding, Saiman
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Catalytic pyrolysis of lignin using low-cost materials with different acidities and textural properties as catalysts2019Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 373, s. 846-856Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Catalytic fast pyrolysis of lignin was performed using low-cost materials with different acidities and textural properties as catalysts in the present work. The main focus is to understand the role of low-cost catalysts in the fast pyrolysis of lignin. The four most commonly used low-cost catalysts, ilmenite (FeTiO3), bentonite (Al-Si-OH), activated carbon (AC) and red mud (RM), were selected. The results show that bentonite, red mud and activated carbon effectively enhance the dehydration reaction, which is regarded as the dominant way to eliminate oxygen during the pyrolysis process, due to the existence of strong acidic sites. However, only activated carbon is found to be effective in promoting the production of monocyclic aromatic hydrocarbons (MAHs). Two metallic catalysts, i. e., bentonite and red mud, have strong acidities but quite low surface areas and less porous structures. Therefore, the dehydrated intermediates produced are especially easy to repolymerize to form char or coke without the restriction of obtaining a porous structure during the pyrolysis process. Activated carbon has not only a certain acidity but also a rich porous structure. Lignin fast pyrolysis-derived oxygenates can diffuse and react on the well-dispersed active sites within the pores of activated carbons. The catalytic performance of the activated carbon are supposed to be determined by the pore size. Only pores of similar size to lignin fast pyrolysis-derived oxygenates (0.6-1 nm) seems to be effective for the production of MAHs. Pores larger or smaller than lignin fast pyrolysis-derived oxygenates both tend to cause coke deposition rather than MAHs formation.

  • 18.
    Han, Tong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Lu, X.
    Sun, Y.
    Jiang, J.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär G.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Magnetic bio-activated carbon production from lignin via a streamlined process and its use in phosphate removal from aqueous solutions2020Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 708, artikel-id 135069Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin and ferrous salt were mechanically mixed, melted, carbonized and steam activated to produce magnetic bio-activated carbons (MBACs). Phosphate adsorption capacity measurement was conducted on representative MBAC, which has a high surface iron oxide proportion and mesoporous volume. The results indicate that iron species are embedded into the carbon matrix by lignin melting. Steam is not only an activation agent for pore generation and widening but is also effective for the oxidization of Hagg iron carbide produced via ferrous salt decomposition and subsequent reduction during the carbonization process to form magnetite. The porous and magnetic properties and surface iron oxide content of the produced MBACs can be modified by controlling the steam/magnetic biochar (MBC) ratio. The MBAC production process is streamlined and novel, compared with conventional coprecipitation or impregnation methods. The maximum phosphate adsorption onto the representative MBAC product using the best fitting model, i.e., the Langmuir-Freundlich model, is estimated to be 21.18 mg/g, suggesting that the representative MBAC product has a comparable phosphate adsorption capacity to most of the reported MBCs and MBACs.

  • 19.
    Han, Tong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Sophonrat, Nanta
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Evangelopoulos, Panagiotis
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Persson, Henry
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Weihong, Yang
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin2018Ingår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 33, s. 162-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sulfonated Kraft lignin, the most available commercial lignin of today, has high sulfur content due to the extraction and the subsequent sulfonation processes. In this work, the evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin has been studied. Fast Pyrolysis experiments have been done using Py-GC/MS. It is found that main sulfur-containing products in the pyrolytic vapors are present as the following small molecular compounds: H2S, SO2, CH3SH, CH3SCH3, and CH3SSCH3. This indicates that sulfur-containing radicals preferentially combine with the other small radicals such as H and CH3 during fast pyrolysis process. Sulfur is suggested to be mainly present as sulfite (SO3) and sulfide (S) in the sulfonated Kraft lignin. Sulfite that is incorporated into lignin during the sulfonation process mainly result in the formation of SO2. The nature of the sulfur links created during the Kraft pulping process is difficult to determine, but they are supposed to mainly exist in form of sulfide (S) bonds, which lead to the formation of H2S, CH3SH, CH3SCH3 and CH3SSCH3.

  • 20. Iwnicki, S. D.
    et al.
    Orlova, A.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Fartan, M.
    Design of the running gear for the SUSTRAIL freight vehicle2015Ingår i: Stephenson Conference Research for Railways 2015, Institution of Mechanical Engineers , 2015, s. 299-305Konferensbidrag (Refereegranskat)
    Abstract [en]

    The authors are working together in the 'SUSTRAIL' project to design an innovative, sustainable freight vehicle for use in new European markets. Market research has determined that the SUSTRAIL freight vehicle needs to run at up to 140km/h with an axle load of up to 25T. In order to reduce the impact of the increased freight traffic a requirement for a 50% reduction in lateral forces on the track has also been set. These very demanding requirements can not be met without a corresponding step change in suspension design. After a thorough review it was therefore decided that the conventional Y25 type suspension was not appropriate for the SUSTRAIL freight vehicle. The Y25 suspension is very common in European railway operations and this brings advantages for operation and maintenance however it does have a high level of longitudinal stiffness after the small amount of longitudinal clearance at the axle box has been exceeded and this can result in relatively poor curving and high lateral wheel-rail forces. As an alternative a modified version of the Y25 suspension with a double Lenoir link primary suspension has been investigated and shown to produce much lower longitudinal primary stiffness while still utilizing standard components and methods which are well established within the railway industry. Computer simulation tools have been used by the project team to optimize the precise geometric design and the component parameters. In order to improve stability of the vehicle and allow higher speed operation it was decided to assess the benefit of linkages providing longitudinal stiffness between the axleboxes using a radial arm. Various previous designs were considered and the final proposal involves a novel cross bracing arrangement. A prototype SUSTRAIL freight vehicle is now being constructed and will be tested in 2015. 

  • 21.
    Jarnerud, Tova
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialteknologi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär G.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Briquetting of wastes from pulp and paper industries by using AOD converter slag as binders for application in metallurgy2019Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, nr 18, artikel-id 2888Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A number of carbon-rich (containing up to 47 wt% C) and lime-rich (containing up to 96 wt% of CaO-compounds) waste products from the pulp and paper industries can be used in iron and steel industry as fuels and slag formers for various metallurgical processes such as blast furnaces (BF), cupola furnaces (CF), argon oxygen decarburization (AOD) converters and electric arc furnaces (EAF). In most cases, these wastes consist of different size powders. In order to facilitate loading, transportation and charging of these powder wastes, briquetting is required. In this study, a pulverized AOD slag was tested as a binder component for briquetting of CaO-containing wastes (such as mesa, lime mud and fly ash) from pulp and paper industries. Moreover, mechanical testing of the possibilities for loading, transportation and unloading operations were done, specifically drop test trials were done for briquettes with different chemical compositions and treatments such as heating and storage. The results showed that an addition of 10-20% of AOD slag as a binder component followed by heat-treatment at 850 °C significantly improved the mechanical properties of the CaO-containing briquettes. An application of these briquettes will significantly reduce the consumption of natural resources (such as nature lime) in the metallurgical processes. Moreover, it can reduce the landfill area of wastes from pulp and paper industries, which is important from an environmental point-of-view.

  • 22.
    Karasev, Andrey
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Alekseeva, E.
    Lukianov, A.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Characterization of non-metallic inclusions in corrosion -resistance nickel - Based EP718 and 718 alloys by using electrolytic extraction method2019Ingår i: E3S Web of Conferences, EDP Sciences , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    It is known that non-metallic inclusions (NMI) that are formed during steel production and heat treatment can significantly affect the properties of final steel products. Therefore, it is very important to be able to determine the content of harmful NMI in steels. Nickel-based alloys are widely used in the oil and gas recovery industry, due to a good combination of strength and corrosion properties. Earlier studies have shown that the corrosion properties in immersion test and electrochemical tests for Ni-based EP718 alloys are slightly lower than that for 718 alloys. The focus in this study was the influence of different NMI on the corrosion resistance of these alloys. The characteristics of inclusions (such as size, morphology, and chemical composition) were analysed by using the electrolytic extraction method followed by three-dimensional investigations using SEM in combination with EDS. It was found that some non-metallic inclusions in EP718 alloys significantly reduce its corrosion resistance. It was also shown that a primary dissolution of the metal matrix occurs around certain inclusions during electrolytic extraction. Based on obtained results, the corrosion active non-metallic inclusions can be determined in these Nickel-base alloys and some recommendations for optimization of their production technology can be formulated.

  • 23.
    Kellner, Hans E. O.
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Dalarna University, Sweden.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sundqvist, Olle
    Memarpour, Arashk
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Estimation of Non-Metallic Inclusions in Industrial Ni Based Alloys 8252017Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, nr 4, artikel-id UNSP 1600024Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is well known that inclusions affect the properties of the steel and other alloys. The importance of understanding the behavior of the inclusions during production can never be overstated. This study has examined the main types of big size (> 10 mu m) inclusions that exist in Ni-based Alloy at the end of ladle treatment and after casting during industrial production of Ni based Alloys 825. Sources, mechanisms of formation and behavior of different type large size inclusions in Alloy 825 are discussed based on 2 and 3D investigations of inclusion characteristics (such as, morphology, composition, size, and number) and thermodynamic considerations. The large size inclusions found can be divided in spherical (Type I and II) inclusions and in clusters (Type III-V). Type I-A inclusions (Al2O3-CaO-MgO) originate from the slag. Type I-B inclusions and Type II inclusions consist of CaO-Al2O3-MgO and Al2O3-TiO2-CaO, respectively. Both types originate from the FeTi70R alloy. Type III clusters (Al2O3-MgO-CaO) are formed during an Al deoxidation of the Ni-based alloy. Type IV clusters (Al2O3-TiO2-CaO) formed from small inclusions, which are precipitated in local zones which contain high Ti and Al levels. These clusters are transformed to Type III clusters over time in the ladle. Finally, Type V clusters are typical TiN clusters.

  • 24.
    Khodabandeh, Erfan
    et al.
    Amirkabir Univ Technol, Tehran Polytech, Mech Engn Dept, 424 Hafez Ave,POB 15875-4413, Tehran, Iran..
    Akbari, Omid Ali
    Islamic Azad Univ, Young Researchers & Elite Club, Khomeinishahr Branch, Khomeinishahr, Iran..
    Toghraie, Davood
    Islamic Azad Univ, Dept Mech Engn, Khomeinishahr Branch, Khomeinishahr 84175119, Iran..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap. Sharif Univ Technol, Dept Mech Engn, Tehran, Iran..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Numerical investigation of thermal performance augmentation of nanofluid flow in microchannel heat sinks by using of novel nozzle structure: sinusoidal cavities and rectangular ribs2019Ingår i: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 41, nr 10, artikel-id UNSP 443Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we present a numerical simulation of a laminar, steady and Newtonian flow of f-graphene nanoplatelet/water nanofluid in a new microchannel design with factors for increasing heat transfer such as presence of ribs, curves to enable satisfactory fluid mixing and changing fluid course at the inlet and exit sections. The results of this study show that Nusselt number is dependent on nanoparticles concentration, inlet geometry and Reynolds number. As the nanofluid concentration increases from 0 to 0.1% and Reynolds number from 50 to 1000, the Nusselt number enhances nearly up to 3% for increase in fluid concentration and averagely from 15.45 to 54.1 and from 14.5 to 55.9 for geometry with and without rectangular rib, respectively. The presence of ribs in the middle section of microchannel and curves close to hot walls causes a complete mixing of the fluid in different zones. When the nanoparticles concentration is increased, the pressure drop and velocity gradient will become higher. An increased concentration of nanoparticles in contribution with higher Reynolds numbers only increases the fraction factor slightly. (The fraction factor increases nearly 37% and 35% for Re = 50 and 1000, respectively.) The highest uniform temperature distribution can be found in the first zones of fluid in the microchannel and by further movement of fluid toward exit section, because of decreasing difference between surface and fluid temperature, the growth of temperature boundary layer increases and results in non-uniformity in temperature distribution in microchannel and cooling fluid. With decrease in the concentration from 0 to 0.1%, the average outlet temperature and FOM decrease nearby 0.62% and 6.15, respectively.

  • 25.
    Liu, Hailong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Swedish Def Res Agcy, Sweden.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Jönsson, Pär Göran
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A Simulation Study of Particles Generated from Pellet Wear Contacts during a Laboratory Test2016Ingår i: ISIJ INTERNATIONAL, ISSN 0915-1559, Vol. 56, nr 11, s. 1910-1919Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the blast furnace process, material losses occur due to mechanical wear between charged iron ore pellets and are exhausted in the form of dust in the off-gases. A redesigned tribometer combined with a ventilation chamber was developed to identify the dust emission from the mechanical wear contact of pellets. In order to obtain a better understanding of the measurement results, a coupled drift flux with a unified Eulerian deposition model was adopted to investigate particle dispersion and deposition during tests. Two influential factors, namely the air condition (5-20 L/min) and particle size (1-20 mu m) were examined. The predicted results were presented by introducing two parameters, namely the measurable fraction and the deposition fraction. For each air condition, the measurable fraction declines while the deposition fraction rises as particle size grows. The critical size of the particles that becomes airborne and captured at the outlet was identified to be around 20 mu m. In addition, a high airflow rate supplied at the inlet was observed to be favorable for improving the measurable fraction. Nevertheless, the results show that nearly 50% of emitted particles (1-20 mu m) that failed to be captured during tests. Thus it could be expected that these generated particles would be transported deeply in a blast furnace if they are not efficiently removed from the off-gas. As a consequence, they may influence the quality of the products. Furthermore, the validation of the simulation results against the experimental data was achieved by using the predicted measurable fraction.

  • 26.
    Liu, Yu
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Bai, Haitong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Liu, Heping
    Cent Iron & Steel Res Inst, 76 Xueyuan Nanlu, Beijing 100081, Peoples R China..
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Gan, Yong
    Cent Iron & Steel Res Inst, 76 Xueyuan Nanlu, Beijing 100081, Peoples R China..
    Physical and Numerical Modelling on the Mixing Condition in a 50 t Ladle2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 11, artikel-id 1136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The bubbly flow and mixing conditions for gas stirring in a 50t ladle were investigated by using physical modelling and mathematical modelling. In the physical modelling, the effect of the porous plugs' configurations on the tracer homogenization was studied by using a saturated NaCl solution to predict the mixing time and a color dye to show the mixing pattern. In the mathematical modelling, the Euler-Lagrange model and species transport model were used to predict the flow pattern and tracer homogenization, respectively. The results show that, for a +/- 5% homogenization degree, the mixing time with dual plugs using a radial angle of 180 degrees is shortest. In addition, the mixing time using a radial angle of 135 degrees decreases the most with an increased flow rate. The flow pattern and mixing conditions predicted by mathematical modelling agree well with the result of the physical modelling. For a +/- 1% homogenization degree, the influence of the tracer's natural convection on its homogenization pattern cannot be neglected. This is especially true for a 'soft bubbling' case using a low gas flow rate. Overall, it is recommended that large radial angles in the range of 135 degrees 180 degrees are chosen for gas stirring in the present study when using dual porous plugs.

  • 27.
    Liu, Yu
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Liu, H.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Gan, Y.
    Comparison of Euler-Euler Approach and Euler–Lagrange Approach to Model Gas Injection in a Ladle2019Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 90, nr 5, artikel-id 1800494Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The gas injection in a ladle using a porous plug is simulated using both the Euler-Euler and Euler-Lagrange approaches. The effects of various forces, bubble sizes, and bubble injection frequencies on the flow pattern are modeled. For predicting axial velocity and turbulent kinetic energy, the Euler-Lagrange approach fits better than Euler-Euler approach with the measured data. In the Euler-Euler approach, differences in axial velocities and turbulent kinetic energies for various bubble sizes mainly appears in the plume zone. In the Euler-Lagrange approach, different bubble sizes with the same injection frequency have a small impact on the turbulence dissipation. Furthermore, the turbulent dispersion from the gas phase to the liquid phase has an important effect on the plume structure and spout eye formation. For both modeling, the smaller the bubble diameter is, the larger the axial velocity and turbulent kinetic dissipation are in the central zone. For the bubble coalescence and breakup, according to the comparison of two modeling approaches, the Euler-Lagrange approach is more accurate in predicting the flow pattern for gas injection with a porous plug in the ladle.

  • 28.
    Liu, Yu
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi. Central Iron and Steel Research Institute, Beijing, P.R. China.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Liu, Heping
    Cent Iron & Steel Res Inst, Beijing 100081, Peoples R China..
    Jönsson, Pär Göran
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Gan, Yong
    Cent Iron & Steel Res Inst, Beijing 100081, Peoples R China..
    A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy2019Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, nr 1, s. 555-577Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    This article presents a review of the research into gas stirring in ladle metallurgy carried out over the past few decades. Herein, the physical modeling experiments are divided into four major areas: (1) mixing and homogenization in the ladle; (2) gas bubble formation, transformation, and interactions in the plume zone; (3) inclusion behavior at the steel-slag interface and in the molten steel; and (4) open eye formation. Several industrial trials have also been carried out to optimize gas stirring and open eye formation. Approaches for selecting criteria for scaling to guarantee flow similarity between industrial trials and physical modeling experiments are discussed. To describe the bubble behavior and two-phase plume structure, four main mathematical models have been used in different research fields: (1) the quasi-single-phase model, (2) the volume of fluid (VOF) model, (3) the Eulerian multiphase (E-E) model, and (4) the Eulerian-Lagrangian (E-L) model. In recent years, the E-E model has been used to predict gas stirring conditions in the ladle, and specific models in commercial packages, as well as research codes, have been developed gradually to describe the complex physical and chemical phenomena. Furthermore, the coupling of turbulence models with multiphase models is also discussed. For physical modeling, some general empirical rules have not been analyzed sufficiently. Based on a comparison with the available experimental results, it is found that the mathematical models focusing on the mass transfer phenomenon and inclusion behaviors at the steel-slag interface, vacuum degassing at the gas-liquid interface, dissolution rate of the solid alloy at the liquid-solid interface, and the combination of fluid dynamics and thermodynamics need to be improved further. To describe industrial conditions using mathematical methods and improve numerical modeling, the results of physical modeling experiments and industrial trials must offer satisfactory validations for the improvement of numerical modeling.

  • 29.
    Lundkvist, Nicholas
    et al.
    KTH.
    Ni, Peiyuan
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Iguchi, Manabu
    Hokkaido Univ, Grad Sch Engn, Sapporo, Hokkaido 0608628, Japan..
    Tilliander, Anders
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A Physical Modeling Study on Slag Behavior in the AOD Converter Process2018Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, nr 6, artikel-id 1700536Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A water/oil physical model is built up to investigate the slag behavior under the side gas-blowing condition of an AOD process. The critical side-blowing air flow rates for the top oil entrainment and emulsification are investigated. In addition, the oil entrainment with the existence of solid particles is studied. Specifically, the influences of the tuyere size, oil viscosity, oil thickness, and volume fraction of solid particles in oil on the mixing phenomena are studied. It is found that oil viscosity is an important factor for the initial oil entrainment and emulsification. Oil thickness only has a slight influence on these phenomena. The critical air flow rate for both initial oil entrainment and emulsification increases slightly with an increased tuyere size from 2.0 to 3.2 mm. Empirical equations have been proposed to predict the critical air flow rate for the initial oil entrainment and emulsification. Furthermore, solid particles in oil are found to increase the critical air flow rate for an initial entrainment. This may be due to the increase of oil viscosity when solid particles exist in oil. In addition, a new model is developed to predict the oil viscosity when solid particles exist inside it.

  • 30.
    Mu, Wangzhong
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. McMaster University, Canada.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Nakajima, Keiji
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review2017Ingår i: High Temperature Materials and Processes, ISSN 0334-6455, E-ISSN 2191-0324, Vol. 36, nr 4, s. 309-325Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063-1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

  • 31. Nabeel, M.
    et al.
    Alba, M.
    Sun, S.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Dogan, N.
    Characterization of inclusions in high-Mn steel using two-dimensional and three-dimensional methods2018Ingår i: AISTech - Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2018, s. 1483-1491Konferensbidrag (Refereegranskat)
  • 32. Nabeel, M.
    et al.
    Alba, M.
    Sun, S.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Dogan, N.
    Characterization of inclusions in high-Mn steel using two-dimensional and three-dimensional methods2019Ingår i: Iron & Steel Technology, ISSN 1547-0423, Vol. 16, nr 7, s. 74-82Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The characteristics of inclusions in high-manganese steel samples from laboratory-scale experiments were investigated. This was done by two-dimensional and three-dimensional methods. In the two-dimensional investigations, inclusions on polished cross-sections were observed by using automatic scanning electron microscopy analysis. For the three-dimensional investigations, inclusions collected on a film filter after electrolytic extraction were observed. It was found that electrolytic extraction could be successfully applied to high-manganese steels. Further, automatic analysis, which is a common practice in steel industry, has limitations for the detection and classification of nitride inclusions, whereas it was possible to detect nitrides using the three-dimensional method.

  • 33.
    Nabeel, Muhammad
    et al.
    McMaster Univ, 1280 Main St West, Hamilton, ON L8S 4L7, Canada..
    Alba, Michelia
    McMaster Univ, 1280 Main St West, Hamilton, ON L8S 4L7, Canada..
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär G.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Dogan, Neslihan
    McMaster Univ, 1280 Main St West, Hamilton, ON L8S 4L7, Canada..
    Characterization of Inclusions in 3rd Generation Advanced High-Strength Steels2019Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, nr 4, s. 1674-1685Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Samples taken from laboratory-produced 3rd generation advanced high-strength steels, solidified at a low cooling rate, have been investigated to study the characteristics of non-metallic inclusions. Two steels, containing 2 and 5 pct Mn content, were produced for this purpose. A higher number of total inclusions were observed in 5 pct Mn steel. The four main types of inclusions observed were Al2O3, AlN, MnS, and AlSiMn-oxide. These classes were divided into subclasses according to variations in their chemistry. The major subclasses of AlN inclusions are either plate-like or regular in shape and have different size distributions. Thermodynamic calculations suggest that plate-like AlN inclusions are formed at the initial stage of solidification, while faceted/regular-shaped inclusions are precipitated toward the end of solidification. Moreover, it was found that the size of nitride inclusions is related to their N content. This phenomenon is discussed from the viewpoint of nucleation theory.

  • 34.
    Nabeel, Muhammad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Metallografi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Extreme Value Distribution of clusters in REM-alloyed stainless steelsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    An extreme value distribution (EVD) analysis has been applied for three dimensional (3D) investigations of clusters observed in REM alloyed stainless steel samples. The presence of observed unit areas without any clusters has been discussed. It has been shown that an increase of the observed unit area (AO) significantly improves the correlation of EVD regression lines. Moreover, three different size parameters were considered for EVD analysis. The results show that using the maximum length of clusters (LC) results in a better correlation of EVD regression lines by improving R2 value up to 0.9876 as compared to 0.9656 – 0.9774 for other size parameters. Moreover, a comparison of predicted and observed maximum lengths of clusters showed that there is need of further work on validation of EVD analysis. 

  • 35.
    Nabeel, Muhammad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Friction forces and mechanical dust generation in an iron ore pellet bed subjected to varied applied loadsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Iron ore pellets degrade and generate dust during transportation and handling as well as during the iron making process. This leads to material losses and effects the process efficiency in a negative manner. In order, to reduce the generation of dust it is important to understand the influence of process parameters on the dust formation. An experimental setup was used to measure the dust generation and friction forces caused by abrasion of iron ore pellets in a closed pack bed. A varied load of 1 to 3 kg was applied on the pellet bed but at a constant air flow rate to capture the airborne dust particles. It was observed that an increase of ~67% is observed in the friction and the dust generation in the bed as the applied load increased from 1 to 3 kg. Moreover, the evaluation of the particle size distribution of the generated dust showed that a higher friction in the pellet bed can lead to an increased amount of airborne particles. Moreover, it has been shown that in an air flow the morphology and the orientation of dust particles can influence the air velocity required to transport the particles upwards.   

  • 36.
    Nabeel, Muhammad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Metallografi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Friction Forces and Mechanical Dust Generation in an Iron Ore Pellet Bed Subjected to Varied Applied Loads2017Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 57, nr 4, s. 656-664Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Iron ore pellets degrade and generate dust during transportation and handling as well as during the iron making process. This leads to material losses and effects the process efficiency in a negative manner. In order, to reduce the generation of dust it is important to understand the influence of process parameters on the dust formation. An experimental setup was used to measure the dust generation and friction forces caused by abrasion of iron ore pellets in a closed pack bed. A varied load of 1 to 3 kg was applied on the pellet bed but at a constant air flow rate to capture the airborne dust particles. It was observed that an increase of similar to 67% is observed in the friction and the dust generation in the bed as the applied load increased from 1 to 3 kg. Moreover, the evaluation of the particle size distribution of the generated dust showed that a higher friction in the pellet bed can lead to an increased amount of airborne particles. Moreover, it has been shown that in an air flow the morphology and the orientation of dust particles can influence the air velocity required to transport the particles upwards.

  • 37.
    Nabeel, Muhammad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Metallografi.
    Karasev, Andrey
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Glaser, Bjoern
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Mikro-modellering.
    Characterization of dust generated during mechanical wear of partially reduced iron ore pelletsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    During reduction in a blast furnace (BF), the iron ore pellets undergo structural changes which facilitate dust generation due to the mechanical wear / disintegration of the pellets. The generated dust decreases the permeability and productivity of the BF process. Thus, this study investigates the mechanical wear of iron ore pellets reduced at 500 °C (P500) and 850 °C (P850) and compares the results to the wear of unreduced pellets (P25). Moreover, the dust generated during the wear experiments is also characterized. It was found that pellets reduced at 500 °C exhibit a ~ 16 to 35% higher wear rate than reference unreduced pellets. For the pellets reduced at 850 °C, the mechanical wear is inhibited by a formation of a metallic layer at the outer surface of the pellets. Further, the dust generated due to mechanical wear of reduced pellets contained 3 to 6 times higher amount of coarse particles (>20µm) as compared to the dust from unreduced pellets. The obtained results are explained on the basis of the structural changes which take place during the reduction of pellets. 

  • 38.
    Nakajima, Keiji
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Mu, Wangzhong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Assessment of a Simplified Correlation Between Wettability Measurement and Dispersion/Coagulation Potency of Oxide Particles in Ferrous Alloy Melt2019Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, nr 5, s. 2229-2237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article seeks to demonstrate a direct and simplified correlation between the measurement of the wettability and the agglomeration potency of the inclusion particles in liquid ferrous alloy. The established methodology has been validated by the agreement between the calculated coagulation coefficient of Al2O3 particles and the experimental data in the open literature. Subsequently, the coagulation coefficient of Al2O3, MgO, and Ti2O3 particles in ferrous alloy melts was evaluated quantitatively by the proposed method using the actual experimental data of contact angle and surface tension. Meanwhile, the effect of the matrix composition has been investigated by comparing the Hamaker constant and coagulation coefficient between Ti2O3/pure iron and Ti2O3/low-carbon steel systems. It is noted that the change of coagulation coefficient associated with the contact angle is caused by the formation of a new phase at the oxide/metal interface at the high temperature. The present work aims to provide a deep understanding of the connection between inclusion motion behavior in the liquid alloy and the high temperature interfacial phenomenon.

  • 39. Ni, P.
    et al.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Zhang, T. -A
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Effect of immersion depth of a swirling flow tundish SEN on multiphase flow and heat transfer in Mold2018Ingår i: Metals, ISSN 2075-4701, Vol. 8, nr 11, artikel-id 910Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of the immersion depth of a new swirling flow tundish SEN (Submerged Entry Nozzle) on the multiphase flow and heat transfer in a mold was studied using numerical simulation. The RSM (Reynolds Stress Model) and the VOF (Volume of Fluid) model were used to solve the steel and slag flow phenomena. The results show that the SEN immersion depth can significantly influence the steel flow near the meniscus. Specifically, an increase of the SEN immersion depth decreases the interfacial velocity, and this reduces the risk for the slag entrainment. The calculated Weber Number decreases from 0.8 to 0.2 when the SEN immersion depth increases from 15 cm to 25 cm. With a large SEN immersion depth, the steel flow velocity near the solidification front, which is below the mold level of SEN outlet, was increased. The temperature distribution has a similar distribution characteristic for different SEN immersion depths. The high temperature region is located near the solidification front. Temperature near the meniscus was slightly decreased when the SEN immersion depth was increased, due to an increased steel moving distance from the SEN outlet to the meniscus.

  • 40. Ni, P.
    et al.
    Tanaka, T.
    Suzuki, M.
    Nakamoto, M.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A kinetic model on oxygen transfer at a steel/slag interface under effect of interfacial tension2018Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 58, nr 11, s. 1979-1988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A kinetic model was developed to predict the dynamic change of the oxygen content in the sub-interface region as well as the dynamic change of the interfacial tension between molten steel and slag. The dynamic steel/slag interfacial phenomena are very complex, where the combined effect of thermodynamics and kinetics on the interfacial tension needs to be accounted for. As a first step, the current model only considers the SiO2 decomposition, oxygen adsorption and desorption at the steel/slag interface to realize the modeling of the dynamic change of the steel/slag interface phenomena. The oxygen desorption rate was derived based on the slope of the interfacial tension change over oxygen content. Specifically, the oxygen change with time in a sub-interface was predicted by the current model. The oxygen desorption rate was found to have an important influence on the dynamic change of the oxygen content in the sub-interface region. Furthermore, a low slag viscosity was found to increase the oxygen content at the interface due to the fast supply of SiO2 from the slag bulk to the interface. In addition, the equilibrium constant for the oxygen adsorption at an interface due to the interfacial tension effect increases the oxygen content in the sub-interface region.

  • 41.
    Ni, Peiyuan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A study on the nonmetallic inclusion motions in a swirling flow submerged entry nozzle in a new cylindrical tundish design2018Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 49, nr 2, s. 723-736Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different sizes and shapes of nonmetallic inclusions in a swirling flow submerged entry nozzle (SEN) placed in a new tundish design were investigated by using a Lagrangian particle tracking scheme. The results show that inclusions in the current cylindrical tundish have difficulties remaining in the top tundish region, since a strong rotational steel flow exists in this region. This high rotational flow of 0.7 m/s provides the required momentum for the formation of a strong swirling flow inside the SEN. The results show that inclusions larger than 40 µm were found to deposit to a smaller extent on the SEN wall compared to smaller inclusions. The reason is that these large inclusions have Separation number values larger than 1. Thus, the swirling flow causes these large size inclusions to move toward the SEN center. For the nonspherical inclusions, large size inclusions were found to be deposited on the SEN wall to a larger extent, compared to spherical inclusions. More specifically, the difference of the deposited inclusion number is around 27 pct. Overall, it was found that the swirling flow contains three regions, namely, the isotropic core region, the anisotropic turbulence region and the near-wall region. Therefore, anisotropic turbulent fluctuations should be taken into account when the inclusion motion was tracked in this complex flow. In addition, many inclusions were found to deposit at the SEN inlet region. The plotted velocity distribution shows that the inlet flow is very chaotic. A high turbulent kinetic energy value of around 0.08 m2/s2 exists in this region, and a recirculating flow was also found here. These flow characteristics are harmful since they increase the inclusion transport toward the wall. Therefore, a new design of the SEN inlet should be developed in the future, with the aim to modify the inlet flow so that the inclusion deposition is reduced.

  • 42.
    Ni, Peiyuan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Zhang, T. -A
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Numerical study on the influence of a swirling flow tundish on multiphase flow and heat transfer in mold2018Ingår i: Metals, ISSN 2075-4701, Vol. 8, nr 5, artikel-id 368Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of a new cylindrical swirling flow tundish design on the multiphase flow and heat transfer in a mold was studied. The RSM (Reynolds stress model) and the VOF (volume of fluid) model were used to solve the steel and slag flow phenomena. The effect of the swirling flow tundish design on the temperature distribution and inclusion motion was also studied. The results show that the new tundish design significantly changed the flow behavior in the mold, compared to a conventional tundish casting. Specifically, the deep impingement jet from the SEN (Submerged Entry Nozzle) outlet disappeared in the mold, and steel with a high temperature moved towards the solidified shell due to the swirling flow effect. Steel flow velocity in the top of the mold was increased. A large velocity in the vicinity of the solidified shell was obtained. Furthermore, the risk of the slag entrainment in the mold was also estimated. With the swirling flow tundish casting, the temperature distribution became more uniform, and the dissipation of the steel superheat was accelerated. In addition, inclusion trajectories in the mold also changed, which tend to stay at the top of the mold for a time. A future study is still required to further optimize the steel flow in mold.

  • 43.
    Ni, Peiyuan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Transport and Deposition of Non-Metallic Inclusions in Steel Flows- A Comparison of Different Model Predictions to Pilot Plant Experiment Data2017Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, nr 12, artikel-id UNSP 1700155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inclusion behavior during a ladle teeming process is investigated. A Lagrangian method is used to track different-size inclusions and to compare their behaviors in steel flows, solved by the realizable k-epsilon model with SWF (Standard Wall Function), realizable k-epsilon model with EWT (Enhanced Wall Treatment), and RSM (Reynolds Stress Model). The results show that inclusion tracking based on the realizable k-epsilon model with SWF to predict the steel flow does not agree with the data fromplant experiments. The predicted number of inclusions touching the wall shows almost no dependence on inclusion size. This is due to that the boundary layer is not resolved. The inclusion deposition predicted using the realizable k-epsilon model with EWT and the RSM model to predict the steel flow generally agrees with the experimental observations. However, the large size inclusion deposition is over-predicted when using the realizable k-epsilon model with EWT. More specifically, the prediction for 20 mu m inclusions is three times larger than that with the RSM. This is due to that this model cannot calculate the anisotropic turbulence fluctuations. In summary, the turbulence properties in the near-wall boundary layer are found to be very important for a good prediction on inclusion deposition.

  • 44.
    Ni, Peiyuan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Northeastern Univ, Peoples R China.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär Göran
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Deposition of particles in liquid flows in horizontal straight channels2016Ingår i: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 62, s. 166-173Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A flow in a horizontal channel is an important method for the transport of materials, products and/or waste gases/liquids. The deposition of particles in a horizontal channel may clog the flow path. The purpose of this paper is to extend the use of a developed Eulerian deposition model to liquid flows in horizontal straight channels to predict the particle deposition rate. For a horizontal pipe, the deposition rates may differ greatly along a cross section, due to the influences of gravity and buoyancy. The current deposition model is first applied to air flows to enable a comparison with available experimental data. Then, the model is applied to liquid flows in horizontal straight pipes. The effects of gravity, buoyancy, water flow rates, wall roughness, particle size and temperature difference in the near-wall boundary layer on the deposition rate have been studied and explained. The results show that the deposition rates of particles increase with an increased flow rate. The gravity separation has a large influence on the deposition of large particle at high and low parts of the horizontal pipe in some flows. Moreover, both the wall roughness and thermophoresis have a significant influence on the deposition rate of small particles. In addition, the roughness also shows an important influence on the large particle deposition at the top of the investigated pipe, due to that a large value of roughness can make the deposition location somewhat far away from the wall, where a stronger turbophoresis exists. The intensity of the turbophoresis relative to the gravity separation before a particle is reaching the deposition location is important for the large particle deposition when the gravity separation play a negative role on the deposition rate. (C) 2016 Elsevier Inc. All rights reserved.

  • 45.
    Ni, Peiyuan
    et al.
    Osaka Univ, Grad Sch Engn, Div Mat & Mfg Sci, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Tanaka, Toshihiro
    Osaka Univ, Grad Sch Engn, Div Mat & Mfg Sci, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Suzuki, Masanori
    Osaka Univ, Grad Sch Engn, Div Mat & Mfg Sci, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Nakamo, Masashi
    Osaka Univ, Grad Sch Engn, Div Mat & Mfg Sci, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Mathematical Modelling Study of Dynamic Composition Change of Steel and Mold Flux in Continuous Casting of Steel2019Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 59, nr 11, s. 2024-2035Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A kinetic model was developed to describe multicomponent reactions and mass transfer at the steel/molten flux interface under the effect of the interfacial tension. This model mainly describes the following interfacial physicochemical phenomena: i) Silica decomposition and oxygen adsorption at the interface, ii) Oxygen and titanium reactions at the interface, iii) Oxygen and aluminum reaction at the interface, iv) Silica mass transfer from the flux bulk to the interface, and v) Dissolution of the formed titanium dioxide and alumina into the flux and its transfer in flux. With this model, the dynamic changes of the mold flux composition, steel composition, interfacial oxygen content and interfacial tension for different mold flux compositions were predicted. Overall, the dynamic composition changes of the mold fluxes in a casting mold were reproduced. The basicity of the mold flux shows a large influence on the dynamic change of its composition. The initial composition change of the mold flux is fast when the flux with a high basicity was used, compared with the case of the mold flux with a low basicity. The interfacial oxygen content and the interfacial tension were found to reach a constant value after the steel/flux reaches a metastable state. In addition, the interfacial adsorption of oxygen due to the interfacial tension effect was found to significantly accelerate the dynamic change process of the steel/mold flux system.

  • 46.
    Ni, Peiyuan
    et al.
    Osaka Univ, Div Mat & Mfg Sci, Grad Sch Engn, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Tanaka, Toshihiro
    Osaka Univ, Div Mat & Mfg Sci, Grad Sch Engn, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Suzuki, Masanori
    Osaka Univ, Div Mat & Mfg Sci, Grad Sch Engn, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Nakamoto, Masashi
    Osaka Univ, Div Mat & Mfg Sci, Grad Sch Engn, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    A Kinetic Model of Mass Transfer and Chemical Reactions at a Steel/Slag Interface under Effect of Interfacial Tensions2019Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 59, nr 5, s. 737-748Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new kinetic model was developed to predict the dynamic change of the interfacial oxygen content and the steel/slag interfacial tension. This model mainly describes the following interfacial physicochemical phenomena: i) Silica decomposition and oxygen adsorption at the interface, ii) Oxygen and aluminum reactions at the interface, iii) Oxygen desorption from the interface, iv) Silica mass transfer from the slag to the interface, v) Dissolution of the formed alumina into the slag and its transfer in slag and vi) Blockage on the silica mass transfer, to come in contact with the steel, by the accumulation of the formed alumina at the interface. With this model, the dynamic changes of the interfacial oxygen contents under different aluminum contents in steel and different slag viscosities were predicted. Overall, the interfacial oxygen content was found to increase with a decreased aluminum content and a decreased slag viscosity. Furthermore, the aluminum reaction rate can significantly influence the interfacial oxygen content as well as the interfacial tension. In addition, the model captured the fast increase of the interfacial tension after passing the minimum value point for the system of a high -Al content steel and a low viscous slag, which is in agreement with the experimental observations. Furthermore, a parameter study was carried out to show the influence of various parameters on the dynamic interfacial phenomena.

  • 47.
    Pirouznia, Pouyan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi. Dalarna Univ, Dept Mat Sci & Engn, SE-79188 Falun, Sweden.;Voestalpine Precis Strip AB, Res & Dev Dept, SE-68428 Munkfors, Sweden..
    Andersson, Nils A. I.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Tilliander, Anders
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    The Impact of the Gas Inlet Position, Flow Rate, and Strip Velocity on the Temperature Distribution of a Stainless-Steel Strips during the Hardening Process2019Ingår i: METALS, ISSN 2075-4701, Vol. 9, nr 9, artikel-id 928Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A non-uniform temperature across the width of martensitic stainless-steel strips is considered to be one of the main reasons why the strip exhibits un-flatness defects during the hardening process. Therefore, the effect of the gas inlet position in this process, on the temperature distribution of the steel strip was investigated numerically. Furthermore, an infrared thermal imaging camera was used to compare the model predictions and the actual process data. The results showed that the temperature difference across the width of the strip decreased by 9% and 14% relative to the calculated temperature and measured values, respectively, when the gas inlet position was changed. This temperature investigation was performed at a position about 63 mm from the bath interface. Moreover, a more symmetrical temperature distribution was observed across the width of the strip. In addition, this study showed that by increasing the amount of the hydrogen flow rate by 2 Nm(3)/h, a 20% reduction of temperature difference across the width of strip was predicted. Meanwhile, the results show that the effect of the strip velocity on the strip temperature is very small.

  • 48.
    Ratnasari, Devy Kartika
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Horn, Antonia
    BIOS BIOENERGIESYST GmbH, Inffeldgasse 21b, A-8010 Graz, Austria..
    Brunner, Thomas
    BIOS BIOENERGIESYST GmbH, Inffeldgasse 21b, A-8010 Graz, Austria..
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    The thermal degradation of lignocellulose biomass with an acid leaching pre-treatment using a H-ZSM-5/Al-MCM-41 catalyst mixture2019Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 257, artikel-id UNSP 116086Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Improvements on the pyrolysis process of biomass fuels are needed to obtain a high-quality of bio-oil. Pretreatment by acid leaching prior to the pyrolysis process is considered to remove Alkali and Alkaline Earth Metal (AAEM) from the biomass, since AAEM adversely affect the catalytic pyrolysis process. Therefore, the main objective of the present work was to determine and compare the effect of mixed-catalysts consisting of H-ZSM-5 and Al-MCM-41, which are used at different ratios in lignocellulose biomass pyrolysis via Thermal Gravimetric Analysis (TGA) for both, un-leached and leached biomass. In addition, the activation energies have been determined based on the solid-state reaction mechanism. The results from the acid leaching treatment showed that the optimum leaching process was set to 30 min, 30 degrees C and 5 wt% acetic acid in the leaching liquid. This resulted in 59%, 95%, 99%, and 96% reduction degree of Calcium (Ca), Magnesium (Mg), Potassium or Kalium (K), and Natrium (Na), respectively. The Higher Heating Values (HHVs) for un-leached and leached biomass were 19.42 and 19.14 MJ/kg, respectively, calculated by using the Milne formula. The HHV value is not significantly influenced by the acid-leaching pre-treatment. Thermogravimetric analysis showed similar trends for the mass loss as a function of temperature and four stages could be determined from the thermal degradation of biomass. There was no significant shift in the temperature profiles between un-leached and leached biomass degradations. However, the removal of AAEM significantly affected the degradation of hemicellulose, cellulose, and lignin. A 12.4-18.2% increase of mass losses could be found in Phase 2 for leached biomass, compared to un-leached biomass. The mass losses in Phase 2 also increased with increased heating rates. From the un-leached biomass experiments using a catalyst mixture, the percentage of mass loss increased from 64.95 wt% at 10 K min(-1) to 68.33 wt% at 50 K min(-1). Moreover, for the leached biomass, it rose from 65.71 wt% at 10 K min(-1) to 66.73 wt % at 30 K min(-1), before decreasing to 62.44 wt% at 50 K min(-1). A lower mass loss in Phase 4 for leached biomass compared to un-leached biomass showed the influence of an AAEM removal. The second order (F2) mechanism was able to illustrate the catalytic pyrolysis process, proven by the result that the coefficient of determination (R-2) was higher than 0.99, which was high compared to other mechanisms. An acid leaching pretreatment led to a reduction in the activation energies. The activation energies for the un-leached biomass were 26.94 and 25.56 kJ mol(-1) at a heating rate of 10 K min(-1) for a process without and with a catalyst mixture, respectively. The activation energies for leached biomass were 24.05 and 21.80 kJ mol(-1). The results also showed that the use of the acid leaching process as a treatment prior to catalytic pyrolysis is positive, since it resulted in high devolatilization and reaction rate.

  • 49.
    Ratnasari, Devy Kartika
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Kinetic Study of an H-ZSM-5/Al MCM-41 Catalyst Mixture and Its Application in Lignocellulose Biomass Pyrolysis2019Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 6, s. 5360-5367Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of H-ZSM-S and Al MCM-41 in a two-stage system of mesoporous and microporous catalysts has been proved to improve the quality of bio-oil. Information about biomass pyrolysis kinetics is important to evaluate biomass as a feedstock for fuel or chemical production as well as efficient design and control of thermochemical processes. In this study, the catalytic pyrolysis kinetics of lignocellulose biomass with a mixed catalyst of H-ZSM-5 and Al-MCM-41 at different ratios is analyzed. The derived activation energies are determined using the Coats-Redfern model and an Avrami mechanism for first order chemical reactions (A1, F1). Bench-scale experiments as well as quantifications of the resulted benzene, toluene, and xylene (BTX) yields have also been investigated. The thermogravimetric analysis DTG results show that the presence of catalyst mixtures has significant effects on the fractions of volatile matter from lignocellulose biomass. Reactivity profiles have been obtained in the temperature range of 180 to 360 degrees C. The results show that the energy activation for lignocellulose biomass at a heating rate of 10 K min(-1) is 134.64 kJ mol(-1) and that the value decreases when using catalysts. However, when the heating rate is increased, the activation energy from the catalytic experiments is 6.3-66.0% higher than that from the biomass pyrolysis experiment. This is due to the production of coke. Overall, a H-ZSM-5/Al MCM-41 ratio of 3:1 is found to be the best catalyst ratio in cracking hemicellulose and cellulose compared to other catalyst mixtures that were studied. The same catalyst ratio also attains the best interaction, in terms of a BTX product selectivity. The optimum activity of this catalyst mixture is reached at a temperature of 500 degrees C.

  • 50.
    Ratnasari, Devy Kartika
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Two-stage ex-situ catalytic pyrolysis of lignocellulose for the production of gasoline-range chemicals2018Ingår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 134, s. 454-464Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The appropriate system is needed to produce a scalable and economically viable renewable energy from biomass. The objective of this study is to improve the quality of bio-oil, in terms of Organic Liquid Product (OLP), water content, acidity, favourable fractions, as well as gasoline-range chemicals. The influence of a staged layered catalyst system consists of a mesoporous catalyst, Al-MCM-41, and a microporous catalyst, HZSM-5, on the bio-oil quality was investigated. Additionally, the effect of reaction temperatures in the range of 400-600 degrees C with the optimum staged catalyst system on the catalytic pyrolysis product was analysed. The experiments of lignocellulosic biomass pyrolysis and catalytic pyrolysis were performed using a fixed bed reactor equipped with oil condensers and a gas collection sample bag. The quality of bio-oil produced from the thermal pyrolysis of lignocellulosic biomass, catalytic pyrolysis with single catalysts, catalytic pyrolysis with the staged catalyst system, as well as catalytic pyrolysis with mixed catalyst system was studied. The results show that Al-MCM-41 with HZSM-5 in the staged catalyst system enhanced the production of favourable compounds: hydrocarbons, phenols, furans, and alcohols. The favourable compounds yield that boosted 5.25-6.43% of that with single HZSM-5 catalyst was produced with HZSM-5:Al-MCM-41 mass ratio of 3:1 and 7:1. The pyrolysis and catalysis temperature of 500 degrees C with HZSM-5:Al-MCM-41 ratio of 3:1 obtained the optimum quality of bio-oil with 11.08 wt.% of OLP, 76.20% of favourable fractions, 41.97 wt.% of water content, low TAN of 43.01 mg-KOH/g, high deoxygenation, as well as high gasoline-range production of 97.89%.

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