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Björkman, Bo
Publications (10 of 194) Show all publications
El-Tawil, A., Björkman, B., Lundgren, M. & Sundqvist Ökvist, L. (2023). The Effect of Bio-Coal Agglomeration and High-Fluidity Coking Coal on Bio-Coke Quality. Metals, 13(1), Article ID 175.
Open this publication in new window or tab >>The Effect of Bio-Coal Agglomeration and High-Fluidity Coking Coal on Bio-Coke Quality
2023 (English)In: Metals, ISSN 2075-4701, Vol. 13, no 1, article id 175Article in journal (Refereed) Published
Abstract [en]

Metallurgical coke with high strength and low reactivity is used in the ironmaking blast furnace. Replacement of some coking coal with bio-coal was shown to result in lower strength and higher reactivity of produced coke due to introduction of reactive bio-coal carbon and ash components catalyzing the Boudouard reaction, but also due to lowering of the coking coal blend fluidity, which influences coke strength and reactivity negatively. The current study aims to investigate the possibility to counteract negative impact from bio-coal addition on fluidity and coke reactivity by using high-fluidity coking coal and by agglomeration of bio-coal before addition. Original bio-coal and micro-agglomerate of bio-coal was added at 10%, 15% and 20% to the coking coal blend. The influence of bio-coals on the coke reactivity was measured by using CO2 in a thermogravimetric analyzer. Selected cokes and bio-cokes were produced in technical scale, and their reactivity and strength were measured in standard tests. The effect on dilatation of adding bio-coal or crushed agglomerates of bio-coal to the coking coal blends was measured in an optical dilatometer. The results show that by using a coking coal blend containing high-fluidity coal with agglomerated bio-coal, the max. contraction is increased, whereas the opposite occurs by using original bio-coal. The results show overlapping between contraction occurring before dilatation and during dilation, which affects max. dilatation. The bio-coke containing high-fluidity coal with agglomerated bio-coal has lower reactivity in comparison to bio-cokes with original bio-coal or bio-coke with agglomerated bio-coal produced from a coking coal blend without high-fluidity coal. The reactivity of coke produced in technical scale, as measured in CRI/CSR tests, shows a similar trend regarding reactivity, as measured by thermogravimetric analysis, on coke produced in laboratory scale.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
agglomerated bio-coal, bio-coke, high-fluidity coking coal, torrefied sawdust
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-95546 (URN)10.3390/met13010175 (DOI)2-s2.0-85146806548 (Scopus ID)
Funder
Swedish Research Council Formas, (FR-2018/0010)
Note

Validerad;2023;Nivå 2;2023-02-08 (joosat);

Licens fulltext: CC BY License

Available from: 2023-02-08 Created: 2023-02-08 Last updated: 2023-09-05Bibliographically approved
Kumar, T. K., Ahmed, H., Alatalo, J. & Björkman, B. (2022). Carburization Behavior of Hydrogen-Reduced DRI Using Synthetic Bio-syngas Mixtures as Fossil-Free Carbon Sources. Journal of Sustainable Metallurgy, 8(4), 1546-1560
Open this publication in new window or tab >>Carburization Behavior of Hydrogen-Reduced DRI Using Synthetic Bio-syngas Mixtures as Fossil-Free Carbon Sources
2022 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 8, no 4, p. 1546-1560Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Springer, 2022
National Category
Mineral and Mine Engineering Inorganic Chemistry
Research subject
Process Metallurgy; Centre - Centre for Advanced Mining & Metallurgy (CAMM)
Identifiers
urn:nbn:se:ltu:diva-93089 (URN)10.1007/s40831-022-00590-0 (DOI)000849157200001 ()2-s2.0-85137457570 (Scopus ID)
Funder
Swedish Energy Agency
Note

Validerad;2023;Nivå 2;2023-04-20 (hanlid)

Available from: 2022-09-19 Created: 2022-09-19 Last updated: 2023-04-20Bibliographically approved
Ahmed, H., Kumar, T. K., Alatalo, J. & Björkman, B. (2022). Effect of carbon concentration and carbon bonding type on the melting characteristics of hydrogen- reduced iron ore pellets. Journal of Materials Research and Technology, 21, 1760-1769
Open this publication in new window or tab >>Effect of carbon concentration and carbon bonding type on the melting characteristics of hydrogen- reduced iron ore pellets
2022 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 21, p. 1760-1769Article in journal (Refereed) Published
Abstract [en]

Decarbonization of the steel industry is one of the pathways towards a fossil-fuel-free environment. The steel industry is one of the top contributors to greenhouse gas emissions. Most of these emissions are directly linked to the use of a fossil-fuel-based reductant. Replacing the fossil-based reductant with green H2 enables the transition towards a fossil-free steel industry. The carbon-free iron produced will cause the refining and steelmaking operations to have a starting point far from today's operations. In addition to carbon being an alloying element in steel production, carbon addition controls the melting characteristics of the reduced iron. In the present study, the effect of carbon content and form (cementite/graphite) in hydrogen-reduced iron ore pellets on their melting characteristics was examined by means of a differential thermal analyser and optical dilatometer. Carburized samples with a carbon content 2 wt%, the molten fraction is higher in the case of carburized samples, which is indicated by the amount of absorbed melting heat.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Carburization, Melting behaviour of hydrogen-based direct reduced iron (DRI), Differential thermal analysis, Optical dilatometer
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-94118 (URN)10.1016/j.jmrt.2022.10.019 (DOI)000877013200007 ()2-s2.0-85144600090 (Scopus ID)
Funder
Swedish Energy AgencyLuleå University of Technology, CAMM2
Note

Validerad;2022;Nivå 2;2022-11-25 (sofila);

Funder: Hybrit RP1

Available from: 2022-11-25 Created: 2022-11-25 Last updated: 2023-10-11Bibliographically approved
Kumar, T. K., Alatalo, J., Ahmed, H. & Björkman, B. (2022). Effect of Temperature and Gas Mixtures on Cementite Formation During the Carburization of Hydrogen-Reduced DRI. Journal of Sustainable Metallurgy, 8(4), 1450-1464
Open this publication in new window or tab >>Effect of Temperature and Gas Mixtures on Cementite Formation During the Carburization of Hydrogen-Reduced DRI
2022 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 8, no 4, p. 1450-1464Article, review/survey (Refereed) Published
Place, publisher, year, edition, pages
Springer Science and Business Media Deutschland GmbH, 2022
National Category
Metallurgy and Metallic Materials Chemical Process Engineering
Research subject
Process Metallurgy; Centre - Centre for Advanced Mining & Metallurgy (CAMM)
Identifiers
urn:nbn:se:ltu:diva-93620 (URN)10.1007/s40831-022-00601-0 (DOI)000864324200001 ()2-s2.0-85139389496 (Scopus ID)
Funder
Swedish Energy Agency, Hybrit Research Program 1
Note

Validerad;2023;Nivå 2;2023-04-20 (hanlid)

Available from: 2022-10-26 Created: 2022-10-26 Last updated: 2023-04-20Bibliographically approved
Andersson, A., Ahmed, H., Sundqvist Ökvist, L. & Björkman, B. (2021). Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments. In: : . Paper presented at The 11th International Conference on Molten Slags, Fluxes and Salts (MOLTEN 2021), Seoul, South Korea, Online, February 21-25, 2021.
Open this publication in new window or tab >>Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments
2021 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

In the present work, a full factorial design of experiments with three factors was performed studying the evaporation of potassium (K) from synthetic blast furnace (BF) slag. The experiments showed that slag temperature and B2 basicity (%CaO/%SiO2) had the greatest effect on the evaporation kinetics, while the effect of the MgO content was comparatively less. The regression model developed based on the experimental design could describe the evaporation of K from actual BF slags fairly well, provided that they were within the experimental matrix of the design of experiments.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-88855 (URN)
Conference
The 11th International Conference on Molten Slags, Fluxes and Salts (MOLTEN 2021), Seoul, South Korea, Online, February 21-25, 2021
Available from: 2022-01-19 Created: 2022-01-19 Last updated: 2023-09-05Bibliographically approved
El-Tawil, A. A., Björkman, B., Lundgren, M., Robles, A. & Sundqvist Ökvist, L. (2021). Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity. Metals, 11(11), Article ID 1752.
Open this publication in new window or tab >>Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity
Show others...
2021 (English)In: Metals, ISSN 2075-4701, Vol. 11, no 11, article id 1752Article in journal (Refereed) Published
Abstract [en]

Coke corresponds to 2/3–3/4 of the reducing agents in BF, and by the partial replacement of coking coals with 5–10% of bio-coal, the fossil CO2 emissions from the BF can be lowered by ~4–8%. Coking coal blends with 5% and 10% additions of bio-coals (pre-treated biomass) of different origins and pre-treatment degrees were carbonized at laboratory scale and with a 5% bio-coal addition at technical scale, aiming to understand the impact on the bio-coal properties (ash amount and composition, volatile matter content) and the addition of bio-coke reactivity. A thermogravimetric analyzer (TGA) connected to a quadrupole mass spectroscope monitored the residual mass and off-gases during carbonization. To explore the effect of bio-coal addition on plasticity, optical dilatometer tests were conducted for coking coal blends with 5% and 10% bio-coal addition. The plasticity was lowered with increasing bio-coal addition, but pyrolyzed biomass had a less negative effect on the plasticity compared to torrefied biomasses with a high content of oxygen. The temperature for starting the gasification of coke was in general lowered to a greater extent for bio-cokes produced from coking coal blends containing bio-coals with higher contents of catalyzing oxides. There was no significant difference in the properties of laboratory and technical scale produced coke, in terms of reactivity as measured by TGA. Bio-coke produced with 5% of high temperature torrefied pelletized biomass showed a similar coke strength as reference coke after reaction.

Place, publisher, year, edition, pages
Minerals, Metals & Materials Society, 2021
Keywords
bio-coals, carbonization, gasification, reactivity, dilatation, fluidity
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-87770 (URN)10.3390/met11111752 (DOI)000725158000001 ()2-s2.0-85118196084 (Scopus ID)
Funder
Swedish Research Council FormasLuleå University of Technology, FR-2018/0010
Note

Validerad;2021;Nivå 2;2021-11-08 (beamah)

Available from: 2021-11-04 Created: 2021-11-04 Last updated: 2023-09-05Bibliographically approved
El-Tawil, A., Björkman, B., Lundgren, M., Bäck, F. & Sundqvist Ökvist, L. (2021). Influence of Modified Bio-Coals on Carbonization and Bio-Coke Reactivity. Metals, 12(1), Article ID 61.
Open this publication in new window or tab >>Influence of Modified Bio-Coals on Carbonization and Bio-Coke Reactivity
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2021 (English)In: Metals, ISSN 2075-4701, Vol. 12, no 1, article id 61Article in journal (Refereed) Published
Abstract [en]

Substitution of coal in coking coal blend with bio-coal is a potential way to reduce fossil CO2 emissions from iron and steelmaking. The current study aims to explore possible means to counteract negative influence from bio-coal in cokemaking. Washing and kaolin coating of bio-coals were conducted to remove or bind part of the compounds in the bio-coal ash that catalyzes the gasification of coke with CO2. To further explore how the increase in coke reactivity is related to more reactive carbon in bio-coal or catalytic oxides in bio-coal ash, ash was produced from a corresponding amount of bio-coal and added to the coking coal blend for carbonization. The reaction behavior of coals and bio-coals under carbonization conditions was studied in a thermogravimetric analyzer equipped with a mass spectrometer during carbonization. The impact of the bio-coal addition on the fluidity of the coking coal blend was studied in optical dilatometer tests for coking coal blends with and without the addition of bio-coal or bio-coal ash. The result shows that the washing of bio-coal will result in lower or even negative dilatation. The washing of bio-coals containing a higher amount of catalytic components will reduce the negative effect on bio-coke reactivity, especially with acetic acid washing when the start of gasification temperature is less lowered. The addition of bio-coal coated with 5% kaolin do not significantly lower the dilatation-relative reference coking coal blend. The reactivity of bio-cokes containing bio-coal coated with kaolin-containing potassium oxide was higher in comparison to bio-coke containing the original bio-coal. The addition of ash from 5% of torrefied bio-coals has a moderate effect on lowering the start of gasification temperature, which indicates that the reactive carbon originating from bio-coal has a larger impact.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
bio-coals, washing, kaolin, ash, coking, volatile matter
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-88709 (URN)10.3390/met12010061 (DOI)000747640300001 ()2-s2.0-85121723271 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-11 (johcin)

Available from: 2022-01-11 Created: 2022-01-11 Last updated: 2023-09-05Bibliographically approved
Orre, J., Sundqvist Ökvist, L., Bodén, A. & Björkman, B. (2021). Understanding of Blast Furnace Performance with Biomass Introduction. Minerals, 11(2), Article ID 157.
Open this publication in new window or tab >>Understanding of Blast Furnace Performance with Biomass Introduction
2021 (English)In: Minerals, E-ISSN 2075-163X, Vol. 11, no 2, article id 157Article in journal (Refereed) Published
Abstract [en]

The blast furnace still dominates the production and supply of metallic units for steelmaking. Coke and coal used in the blast furnace contribute substantially to CO2 emissions from the steel sector. Therefore, blast furnace operators are making great efforts to lower the fossil CO2 emissions and transition to fossil-free steelmaking. In previous studies the use of pre-treated biomass has been indicated to have great potential to significantly lower fossil CO2 emissions. Even negative CO2 emission can be achieved if biomass is used together with carbon capture and storage. Blast furnace conditions will change at substantial inputs of biomass but can be defined through model calculations when using a model calibrated with actual operational data to define the key blast furnace performance parameters. To understand the effect, the modelling results for different biomass cases are evaluated in detail and the overall performance is visualised in Rist- and carbon direct reduction rate (CDRR) diagrams. In this study injection of torrefied biomass or charcoal, top charging of charcoal as well as the use of a combination of both methods are evaluated in model calculations. It was found that significant impact on the blast furnace conditions by the injection of 142 kg/tHM of torrefied biomass could be counteracted by also top-charging 30 kg/tHM of charcoal. With combined use of the latter methods, CO2-emissions can be potentially reduced by up to 34% with moderate change in blast furnace conditions and limited investments.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
bio-coal, blast furnace, heat and mass balance, Rist diagram, CDRR diagram
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy; Centre - Centre for Advanced Mining & Metallurgy (CAMM)
Identifiers
urn:nbn:se:ltu:diva-82826 (URN)10.3390/min11020157 (DOI)000622847500001 ()2-s2.0-85100178644 (Scopus ID)
Funder
Luleå University of Technology
Note

Validerad;2021;Nivå 2;2021-02-09 (alebob)

Available from: 2021-02-09 Created: 2021-02-09 Last updated: 2024-01-17Bibliographically approved
Ahmed, H., Sideris, D., Lennartsson, A., Prasad, P. N., Sundqvist Ökvist, L., From, L.-E., . . . Björkman, B. (2020). Effect of the Ash from H2‐Rich Carbonaceous Materials on the Physicochemical Properties of Raceway Slag and Coke Reactivity. Paper presented at 4th European Steel Technology and Application Days (ESTAD), 24-28 June, 2019, Düsseldorf, Germany. Steel Research International, 91(11), Article ID 2000098.
Open this publication in new window or tab >>Effect of the Ash from H2‐Rich Carbonaceous Materials on the Physicochemical Properties of Raceway Slag and Coke Reactivity
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2020 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 91, no 11, article id 2000098Article in journal (Refereed) Published
Abstract [en]

The iron and steel industry is one of the most important sectors worldwide, and it has a great impact on the global economy; however, this sector is still highly dependent on fossil carbon. To decrease this dependency, approaches to partially replace the injected pulverized coal with secondary, highly reactive, renewable (biomass) and H2‐rich materials have been studied. The injection of such materials is expected to significantly decrease the emitted CO2 from blast furnaces. However, due to the different ash composition of these alternative materials (especially alkali and alkaline earth metals) compared to that of ordinary injected coal, these materials are expected to alter the raceway slag properties and affect the coke reactivity. In the present article, the effect of the ash from different hydrogen‐rich carbonaceous materials on the raceway slag physicochemical properties as well as coke reactivity is reported. The melting characteristics of the ash briquettes in contact with the coke and wettability of the melted ash on the coke surface are determined visually using an optical heating microscope. The effect of the ash on the coke reactivity is studied by means of thermogravimetry under a continuous flow of CO2.

Place, publisher, year, edition, pages
John Wiley & Sons, 2020
Keywords
biomass, blast furnace, injection, iron making, plastic
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-79179 (URN)10.1002/srin.202000098 (DOI)000538494300001 ()2-s2.0-85085933072 (Scopus ID)
Conference
4th European Steel Technology and Application Days (ESTAD), 24-28 June, 2019, Düsseldorf, Germany
Funder
Swedish Energy Agency
Note

Godkänd;2020;Nivå 0;2020-11-30 (alebob);Konferensartikel i tidskrift;

Finansiär: CAMM2, Center of Advanced Mining and Metallurgy at LTU;

For correction, see: Ahmed, H., Sideris, D., Lennartsson, A., Prasad, P.N., Sundqvist-Ökvist, L., From, L., Orre, J. and Björkman, B. (2020), Effect of the Ash from H2-Rich Carbonaceous Materials on the Physicochemical Properties of Raceway Slag and Coke Reactivity. steel research int., 91: 2000640. https://doi.org/10.1002/srin.202000640

Available from: 2020-06-04 Created: 2020-06-04 Last updated: 2023-09-05Bibliographically approved
Ahmed, H., Sideris, D. & Björkman, B. (2020). Injection of H2-rich carbonaceous materials into the blast furnace: devolatilization, gasification and combustion characteristics and effect of increased H2–H2O on iron ore pellets reducibility. Journal of Materials Research and Technology, 9(6), 16029-16037
Open this publication in new window or tab >>Injection of H2-rich carbonaceous materials into the blast furnace: devolatilization, gasification and combustion characteristics and effect of increased H2–H2O on iron ore pellets reducibility
2020 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 9, no 6, p. 16029-16037Article in journal (Refereed) Published
Abstract [en]

Increasing the share of hydrogen in reduction of iron oxide in the blast furnace iron making will directly reduce the share of blast furnace greenhouse gas emissions. In the present study, injection of H2-rich biomass and plastic materials was studied in terms of its devolatilization, gasification and combustion characteristics. The released gases were identified using mass spectroscopy attached to a thermogravimetric analyzer and the corresponding kinetics parameters were estimated.

The devolatilization was found to occur through two or more steps. The first step is always associated with the release of CO2, CO, H2, H2O and hydrocarbons while only CO and H2 were detected during the later steps. Combustion and gasification starting temperatures of char of H2-rich carbonaceous materials were lower than that of pulverized coal char by ≥ 100 °C. The estimated activation energies suggested that, under the present conditions, devolatilization, gasification and combustion were chemically controlled. Carbon reactivity of the char of the studied H2-rich carbonaceous materials were higher than that of pulverized coal. Moreover, increased H2–H2O content in the blast furnace gas, due to injected H2-rich carbonaceous materials, was found to improve the iron ore pellets reduction kinetics.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Injection of biomass, Injection of waste plastic, Blast furnace, iron making, devolatilization, gasification, combustion, kinetics
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-81610 (URN)10.1016/j.jmrt.2020.11.042 (DOI)000607358900007 ()2-s2.0-85107964035 (Scopus ID)
Funder
Swedish Energy AgencyLuleå University of Technology
Note

Validerad;2021;Nivå 2;2021-02-04 (alebob)

Available from: 2020-11-24 Created: 2020-11-24 Last updated: 2021-12-13Bibliographically approved
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