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Publications (10 of 32) Show all publications
Liu, Y., Ersson, M., Liu, H., Jönsson, P. G. & Gan, Y. (2019). A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 50(1), 555-577
Open this publication in new window or tab >>A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy
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2019 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 1, p. 555-577Article, review/survey (Refereed) Published
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.

Place, publisher, year, edition, pages
SPRINGER, 2019
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-243935 (URN)10.1007/s11663-018-1446-x (DOI)000456070300052 ()2-s2.0-85056988962 (Scopus ID)
Note

QC 20190313

Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-03-13Bibliographically approved
Lundkvist, N., Ni, P., Iguchi, M., Tilliander, A. & Jönsson, P. (2018). A Physical Modeling Study on Slag Behavior in the AOD Converter Process. Steel Research International, 89(6), Article ID 1700536.
Open this publication in new window or tab >>A Physical Modeling Study on Slag Behavior in the AOD Converter Process
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2018 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, no 6, article id 1700536Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
AOD, Emulsification, Entrainment, Physical modeling, Slag viscosity
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-231210 (URN)10.1002/srin.201700536 (DOI)000434279200007 ()2-s2.0-85044857849 (Scopus ID)
Note

QC 20180628

Available from: 2018-06-28 Created: 2018-06-28 Last updated: 2018-06-28Bibliographically approved
Ternstedt, P., Ni, P., Lundqvist, N., Tilliander, A. & Jönsson, P. G. (2018). A physical modelling study to determine the influence of slag on the fluid flow in the AOD converter process. Ironmaking & steelmaking, 45(10), 944-950
Open this publication in new window or tab >>A physical modelling study to determine the influence of slag on the fluid flow in the AOD converter process
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2018 (English)In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 45, no 10, p. 944-950Article in journal (Refereed) Published
Abstract [en]

A 1:4.6 scale physical model of a production argon oxygen decarburisation (AOD) converter was used to study the influence of top slag on the AOD process. Specifically, the gas penetration depth, fluid flow and slag behaviour under different nozzle diameters, nozzle numbers and gas flow rates were studied. The results show that the relative gas penetration depth generally increases linearly with an increased gas flow rate and a decreased nozzle size. Furthermore, the slag thickness increases linearly with an increased gas flow rate. In addition, the open-eye size was found to increase exponentially with an increased gas flow rate. Overall, three kinds of fluid flow patterns were found in the experiments: (i) a counter-clockwise rotation, (ii) a clockwise rotation and (iii) a double circulation with the plume in the middle of the converter. A counter-clockwise rotation was most common for the current experimental conditions.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
Physical modelling, AOD, slag, side-gas injection, penetration depth
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-240764 (URN)10.1080/03019233.2017.1415012 (DOI)000453823900014 ()2-s2.0-85039167810 (Scopus ID)
Note

QC 20190107

Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Ni, P., Ersson, M., Jonsson, L. T. & Jönsson, P. (2018). A study on the nonmetallic inclusion motions in a swirling flow submerged entry nozzle in a new cylindrical tundish design. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 49(2), 723-736
Open this publication in new window or tab >>A study on the nonmetallic inclusion motions in a swirling flow submerged entry nozzle in a new cylindrical tundish design
2018 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 49, no 2, p. 723-736Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-238356 (URN)10.1007/s11663-017-1162-y (DOI)000426808500024 ()2-s2.0-85047456102 (Scopus ID)
Note

QC 20181113

Available from: 2018-11-12 Created: 2018-11-12 Last updated: 2018-11-12Bibliographically approved
Al-Saadi, M., Karasev, A., Jönsson, P. & Sandberg, F. (2018). Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression. In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October: . Paper presented at 3rd International Conference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19 October. , Article ID 114.
Open this publication in new window or tab >>Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression
2018 (English)In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October, 2018, article id 114Conference paper, Published paper (Refereed)
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-235343 (URN)
Conference
3rd International Conference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19 October
Note

QCR 20181008

Available from: 2018-09-21 Created: 2018-09-21 Last updated: 2018-10-08Bibliographically approved
Svidró, P., Diószegi, A. & Jönsson, P. (2018). Determination of pressure in the extradendritic liquid area during solidification. Journal of thermal analysis and calorimetry (Print), 132(3), 1661-1667
Open this publication in new window or tab >>Determination of pressure in the extradendritic liquid area during solidification
2018 (English)In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 132, no 3, p. 1661-1667Article in journal (Refereed) Published
Abstract [en]

Complex-shaped lamellar graphite iron castings are susceptible to casting defects related to the volume change during solidification. The formations of these recurring defects are caused by the flow of the liquid in the intradendritic area, between the austenite dendrite arms, and in the extradendritic area between the austenite grains. The conditions for the liquid flow, in turn, are determined by the solidification behavior. The present study suggests a new measurement method and a novel calculation algorithm to determine the pressure of the extradendritic liquid during solidification. The method involves a spherical sample suspended in a measurement device, where the temperature and the volume changes are measured during solidification. The calculation algorithm is based on the numerical interpretation of the Clausius-Clapeyron equation where the temperature variation, the volume change and the released latent heat are processed to determine the local pressure of the extradendritic liquid area during solidification.

Place, publisher, year, edition, pages
Springer Netherlands, 2018
Keywords
Volume change measurement, Fourier thermal analysis, Clausius-Clapeyron equation, Extradendritic liquid pressure, Lamellar graphite iron
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-225417 (URN)10.1007/s10973-018-7088-z (DOI)000432215600022 ()2-s2.0-85042940249 (Scopus ID)
Funder
Knowledge Foundation
Note

QC 20180416

Available from: 2018-04-04 Created: 2018-04-04 Last updated: 2018-05-31Bibliographically approved
Wang, S., Persson, H., Weihong, Y. & Jönsson, P. (2018). Effect of H2 as Pyrolytic Agent on the Product Distribution during Catalytic Fast Pyrolysis of Biomass Using Zeolites. Energy & Fuels
Open this publication in new window or tab >>Effect of H2 as Pyrolytic Agent on the Product Distribution during Catalytic Fast Pyrolysis of Biomass Using Zeolites
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029Article in journal (Refereed) Published
Abstract [en]

Bio-oil generated from catalytic fast pyrolysis or hydrotreating processes represents one of the most promising alternatives to liquid fossil fuels. The use of H2 as carrier gas in the pyrolysis of biomass requires further research to study the catalytic fast pyrolysis reactions in the case of using reactive atmosphere. In this work, pyrolysis experiments with lignocellulosic biomass have been performed in a fixed bed reactor in H2 and N2 atmospheres with/without HZSM-5 additions to investigate the influence of the pyrolytic agents during fast pyrolysis of biomass and upgrading of pyrolytic vapors over a zeolitic catalyst. It was found that in a H2 atmosphere, H2 was consumed in both noncatalytic and catalytic pyrolysis processes, respectively. Higher yields of nonaqueous liquids and permanent gases are obtained in a H2 atmosphere compared to a N2 atmosphere. A catalytic pyrolysis process using HZSM-5 in a H2 atmosphere increased the production of polymer aromatic hydrocarbons and suppressed the production of monomer aromatic hydrocarbons compared to similar tests performed in a N2 atmosphere. The results show an overall increased activity of HZSM-5 in the reactive H2 atmosphere compared to a N2 atmosphere.

Keywords
biomass, pyrolysis, hydrogen, HZSM-5, 生物质, 生物燃料, HZSM-5, 催化裂解, 氢气
National Category
Bioenergy Chemical Engineering Biochemicals
Research subject
Chemical Engineering; Energy Technology; Biotechnology
Identifiers
urn:nbn:se:kth:diva-232341 (URN)10.1021/acs.energyfuels.8b01779 (DOI)000442448300052 ()2-s2.0-85049616561 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 2018-07-20

Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2018-09-07Bibliographically approved
Han, T., Sophonrat, N., Evangelopoulos, P., Persson, H., Weihong, Y. & Jönsson, P. (2018). Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin. Journal of Analytical and Applied Pyrolysis, 33, 162-168
Open this publication in new window or tab >>Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin
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2018 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 33, p. 162-168Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Chemical Engineering Materials Engineering
Identifiers
urn:nbn:se:kth:diva-229683 (URN)10.1016/j.jaap.2018.04.006 (DOI)000435747900020 ()2-s2.0-85045121473 (Scopus ID)
Funder
Swedish Research Council Formas
Note

QC 20180611

Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-07-23Bibliographically approved
Svensson, J., Larsson, F., Memarpour, A., Ekerot, S., Brabie, V. & Jönsson, P. (2018). Implementation of an YSZ coating material to prevent clogging of the submerged entry nozzle (SEN) during continuous casting of Ce-treated steels. Ironmaking & steelmaking, 45(2), 105-113
Open this publication in new window or tab >>Implementation of an YSZ coating material to prevent clogging of the submerged entry nozzle (SEN) during continuous casting of Ce-treated steels
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2018 (English)In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 45, no 2, p. 105-113Article in journal (Refereed) Published
Abstract [en]

The possibility to reduce clogging in the submerged entry nozzle (SEN) during continuous casting of Ce alloyed stainless steels has been studied. This was done by implementing a new plasma coating material, consisting of yttria stabilized zirconia (YSZ). The coating was first tested in pilot-plant trials; where the amount of steel teemed through the plasma coated nozzles was monitored. Thereafter, samples of the coatings from the nozzles were studied using a FEG-SEM equipped with EDS. In addition, the coating material was tested in industrial trials where the performance was judged with respect to the clogging tendency detected as the movement of the stopper rod. The results from both the pilot-plant trials and industrial trials showed that the use of an YSZ coating led to a decreased clogging tendency during the casting in comparison to when using an uncoated SEN. Specifically, the pilot-plant trials showed that the clogging factor was lowered when implementing the YSZ coatings. Furthermore, the industrial trials showed that the clogging tendency, measured by the stopper rod movements, were lower when implementing the YSZ coating.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
Continuous casting, Clogging, Rare earth metals, Submerged entry nozzle, New coating material, Plasma coating, Yttria stabilised zirconia, Stainless steel, Pilot-plant trials, Industrial plant trials
National Category
Metallurgy and Metallic Materials
Research subject
Metallurgical process science
Identifiers
urn:nbn:se:kth:diva-196661 (URN)10.1080/03019233.2016.1245916 (DOI)000438587100002 ()2-s2.0-84994187845 (Scopus ID)
Projects
JERNKONTORETS FORSKNING, Delrapport från pilotförsök och industriförsök med ZrO2-belagda dysor och gjutrör genomförda hos ComdiCast AB respektive Outokumpu Stainless AB, Förbättrad processteknik vid stränggjutning av stål speciellt känsliga för igensättningar, Kommitté JK 23052
Funder
VINNOVA, Kommitté JK 23052
Note

QC 20161129

Available from: 2016-11-17 Created: 2016-11-17 Last updated: 2018-08-02Bibliographically approved
Al-Saadi, M., Jönsson, P., Sandberg, F., Karasev, A. & Jonsson, S. (2018). Microstructure characterisation in alloy 825. In: : . Paper presented at 17th International Conference on Metal Forming, Metal Forming 2018, 16-19 September 2018, Toyohashi, Japan (pp. 1626-1634). , 15
Open this publication in new window or tab >>Microstructure characterisation in alloy 825
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2018 (English)Conference paper, Published paper (Refereed)
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-234261 (URN)10.1016/j.promfg.2018.07.294 (DOI)
Conference
17th International Conference on Metal Forming, Metal Forming 2018, 16-19 September 2018, Toyohashi, Japan
Note

QC 20180906

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-09-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9775-0382

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