Experiences of Bio-Coal Applications in the Blast Furnace Process—Opportunities and Limitations

Ökvist, Lena Sundqvist; Lundgren, Maria

doi:10.3390/min11080863

Cited by 18 publications

(13 citation statements)

References 15 publications

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“…In general, for good-quality coke, the CSR index must be high, whereas the CRI is low [53]. In this work, up to 15 wt.% of the coconut shells, CSR index (55.1%), and CRI index (29.8%) remained at workable-level biocoke for blast-furnace applications, which is CSR 74-50 and CRI 19-30 [2,31,39,54].…”

Section: Csr and Cri Testsmentioning

confidence: 68%

Types and Composition of Biomass in Biocoke Synthesis with the Coal Blending Method

Yustanti

Wardhono

Mursito³

et al. 2021

Energies

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The steelmaking industry requires coke as a reducing agent, as an energy source, and for its ability to hold slag in a blast furnace. Coking coal as raw coke material is very limited. Studying the use of biomass as a mixture of coking coal in the synthesis of biocoke is necessary to reduce greenhouse gas coal emissions. This research focuses on biomass and heating temperature through the coal blending method to produce biocoke with optimal mechanical properties for the blast-furnace standard. The heating temperature of biomass to biochar was evaluated at 400, 500, and 600 °C. The blending of coking coal with biochar was in the compositions of 95:5, 85:15, and 75:25 wt.%. A compacting force of 20 MPa was employed to produce biocoke that was 50 mm in diameter and 27 mm thick using a hot cylinder dye. The green sample was heated at 1100 °C for 4 h, followed by quenching with a water medium, resulting in dense samples. Increasing heating temperature is generally directly proportional to an increase in fixed carbon and calorific value. Biocoke that meets several blast-furnace criteria is a coal mixture with coconut-shell charcoal of 85:15 wt.%. Carbonization at 500 °C, yielding fixed carbon, calorific value, and compressive strength, was achieved at 89.02 ± 0.11%; 29.681 ± 0.46 MJ/kg, and 6.53 ± 0.4 MPa, respectively. This product meets several criteria for blast-furnace applications, with CRI 29.8 and CSR 55.1.

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Section: Csr and Cri Testsmentioning

confidence: 68%

Types and Composition of Biomass in Biocoke Synthesis with the Coal Blending Method

Yustanti

Wardhono

Mursito³

et al. 2021

Energies

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“… 134 However, fuel injection via the tuyeres is considered by many as the easiest way to mitigate CO 2 emissions via the use of bio-coal as it does not significantly affect the BF performance. 135 In fact, it was reported that the complete substitution of coal by bio-coal for fuel injection had equal or better combustion performance than its fossil counterpart. 136 It was estimated that a 33% reduction in CO 2 emission could be obtained using 100% charcoal for fuel injection.…”

Section: Greener Reactants and Recycled Feeds In Pyrometallurgymentioning

confidence: 99%

“… 136 It was estimated that a 33% reduction in CO 2 emission could be obtained using 100% charcoal for fuel injection. 135 In the work of Okvist and Lundgren, 135 it was found that the substitution of 5% biocoal in briquettes and 2–5% in coke had moderate beneficial impacts on the BF CO 2 emissions while not impairing too much the behaviour of the reactor. 135 In another study, the successful incorporation of briquettes containing 1.8 wt% torrefied saw dust in a BF for several weeks was demonstrated.…”

Section: Greener Reactants and Recycled Feeds In Pyrometallurgymentioning

confidence: 99%

“… 135 In the work of Okvist and Lundgren, 135 it was found that the substitution of 5% biocoal in briquettes and 2–5% in coke had moderate beneficial impacts on the BF CO 2 emissions while not impairing too much the behaviour of the reactor. 135 In another study, the successful incorporation of briquettes containing 1.8 wt% torrefied saw dust in a BF for several weeks was demonstrated. The lower carbon consumption was attributed in this case to an improved gas utilization.…”

Section: Greener Reactants and Recycled Feeds In Pyrometallurgymentioning

confidence: 99%

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Greener reactants, renewable energies and environmental impact mitigation strategies in pyrometallurgical processes: A review

Harvey

Courchesne

et al. 2022

MRS Energy & Sustainability

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Metals and alloys are among the most technologically important materials for our industrialized societies. They are the most common structural materials used in cars, airplanes and buildings, and constitute the technological core of most electronic devices. They allow the transportation of energy over great distances and are exploited in critical parts of renewable energy technologies. Even though primary metal production industries are mature and operate optimized pyrometallurgical processes, they extensively rely on cheap and abundant carbonaceous reactants (fossil fuels, coke), require high power heating units (which are also typically powered by fossil fuels) to calcine, roast, smelt and refine, and they generate many output streams with high residual energy content. Many unit operations also generate hazardous gaseous species on top of large CO2 emissions which require gas-scrubbing and capture strategies for the future. Therefore, there are still many opportunities to lower the environmental footprint of key pyrometallurgical operations. This paper explores the possibility to use greener reactants such as bio-fuels, bio-char, hydrogen and ammonia in different pyrometallurgical units. It also identifies all recycled streams that are available (such as steel and aluminum scraps, electronic waste and Li-ion batteries) as well as the technological challenges associated with their integration in primary metal processes. A complete discussion about the alternatives to carbon-based reduction is constructed around the use of hydrogen, metallo-reduction as well as inert anode electrometallurgy. The review work is completed with an overview of the different approaches to use renewable energies and valorize residual heat in pyrometallurgical units. Finally, strategies to mitigate environmental impacts of pyrometallurgical operations such as CO2 capture utilization and storage as well as gas scrubbing technologies are detailed. This original review paper brings together for the first time all potential strategies and efforts that could be deployed in the future to decrease the environmental footprint of the pyrometallurgical industry. It is primarily intended to favour collaborative work and establish synergies between academia, the pyrometallurgical industry, decision-makers and equipment providers. Graphical abstract Highlights A more sustainable production of metals using greener reactants, green electricity or carbon capture is possible and sometimes already underway. More investments and pressure are required to hasten change. Discussion Is there enough pressure on the aluminum and steel industries to meet the set climate targets? The greenhouse gas emissions of existing facilities can often be partly mitigated by retrofitting them with green technologies, should we close plants prematurely to build new plants using greener technologies? Since green or renewable resources presently have limited availability, in which sector should we use them to maximize their benefits?

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“…The advantage of replacing part of the fossil coal with bio-coal is that the biomass regeneration time is comparatively short [4] and the effects on global warming can be reduced as the carbon cycle is closed [5]. It has been reported that with the partial replacement of coking coals with 5-10% of bio-coal, the fossil CO 2 emissions at the BF can be lowered by ~4-8% [6]. Using bio-coke (bio-coal-containing coke) in the BF has the potential to lower the thermal reserve zone temperature (TRZT) of the BF, as the gasification reaction (reaction of carbon in coke with CO 2 ) can proceed at a lower temperature in the more reactive bio-coke.…”

Section: Introductionmentioning

confidence: 99%

Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity

El-Tawil

Björkman

Lundgren

et al. 2021

Metals

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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.

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Experiences of Bio-Coal Applications in the Blast Furnace Process—Opportunities and Limitations

Cited by 18 publications

References 15 publications

Types and Composition of Biomass in Biocoke Synthesis with the Coal Blending Method

Types and Composition of Biomass in Biocoke Synthesis with the Coal Blending Method

Greener reactants, renewable energies and environmental impact mitigation strategies in pyrometallurgical processes: A review

Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity

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