Analysis of the Usability of Iron Ore Ultra-Fines for Hydrogen-Based Fluidized Bed Direct Reduction—A Review

Wolfinger, Thomas; Spreitzer, Daniel; Schenk, Johannes

doi:10.3390/ma15072687

Cited by 13 publications

(5 citation statements)

References 82 publications

(172 reference statements)

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“…Correlations between the Re and Ar numbers have been reported in the literature, as mentioned in reference [21]. The Ergun equation was originally based on the void fraction (ϵ m f ), as shown in Equation (6).…”

Section: Dimensional Analysismentioning

confidence: 99%

“…When determining the u m f this way, there are no considerations for surface-level properties. The idea of including surface level parameters into first-principles models has received recent attention because of its potential to determine the u m f a priori [6]. The work presented in this manuscript will compare experimental measurements to the existing dimensionless number group methods.…”

Section: Introductionmentioning

confidence: 99%

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Dimensionless Number Group Analysis of Surface-Treated Powders

Ludwig

2023

Powders

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Modeling powder properties remains a complex and difficult area of study because particulate materials can behave differently under variable conditions based on their bulk and surface-level properties. The research presented in this manuscript was designed to support the fundamental understanding of powder systems by joining experimental and theoretical calculations of dimensionless numbers groups for design purposes. In order to do so, this work focused on two critical variables to better understand fluidization design: physical and chemical surface properties. To better resolve the influence of surface properties, surface-treated powders were used. Five different powder samples of varying particle size distribution were characterized using physical property measurements, including pressure drop profiles to obtain the minimum fluidization velocity, density measurements, and particle sizing. Using theoretical equations, the minimum fluidization velocity was also calculated to compare with those obtained experimentally and determine typical dimensionless number groups used in bulk handling system design. The results showed that the theoretically determined values were lower than those calculated using the experimentally umf. In the case of the Reynolds number, the experimental values were 3–20% higher than the theoretical values, which is an important distinction for designing conveying systems and pipeline flow. Similar results were observed for the theoretical and experimental Froude numbers, indicating an important dependence on the cohesive properties of the particle interactions. Additional dimensionless number groups were considered, including the granular bond number and flow factors. To investigate the influence of surface forces, Hamaker constants were utilized for alumina and polydimethylsiloxane in the calculation of the granular bond number. A lower granular bond was observed with a decrease in the Hamaker constant for PDMS, suggesting that the surface forces would be lower for our surface-treated powders.

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Section: Dimensional Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dimensionless Number Group Analysis of Surface-Treated Powders

Ludwig

2023

Powders

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“…Classification of different types of (hydrogen-based or hydrogen-containing) direct reduction methods (showing in part their commercial trade names) in conjunction with different alternatives regarding the required granularity and sintering of the corresponding ores in conjunction with different types of reductants . Figure is reproduced with permission from ref under an open access Creative Commons CC BY license. Copyright 2022, MDPI.…”

Section: Feedstock For Sustainable Metal Production: Minerals Metals ...mentioning

confidence: 99%

“…For many of the conventional pyrometallurgical processes, this form of enrichment and stabilization of the starting ores is of great importance in order to achieve an appropriate mechanical stability and percolation capability of the raw materials and reducing agents in large-volume counter-current reduction reactors. Some process pathways (liquid or solid reduction), feedstock types and dispersion (pellets, lump, fines) and reactor types (shaft, fluidized bed) are shown in Figure . − …”

Section: Feedstock For Sustainable Metal Production: Minerals Metals ...mentioning

confidence: 99%

The Materials Science behind Sustainable Metals and Alloys

Raabe

2023

Chem. Rev.

102

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Production of metals stands for 40% of all industrial greenhouse gas emissions, 10% of the global energy consumption, 3.2 billion tonnes of minerals mined, and several billion tonnes of by-products every year. Therefore, metals must become more sustainable. A circular economy model does not work, because market demand exceeds the available scrap currently by about two-thirds. Even under optimal conditions, at least one-third of the metals will also in the future come from primary production, creating huge emissions. Although the influence of metals on global warming has been discussed with respect to mitigation strategies and socio-economic factors, the fundamental materials science to make the metallurgical sector more sustainable has been less addressed. This may be attributed to the fact that the field of sustainable metals describes a global challenge, but not yet a homogeneous research field. However, the sheer magnitude of this challenge and its huge environmental effects, caused by more than 2 billion tonnes of metals produced every year, make its sustainability an essential research topic not only from a technological point of view but also from a basic materials research perspective. Therefore, this paper aims to identify and discuss the most pressing scientific bottleneck questions and key mechanisms, considering metal synthesis from primary (minerals), secondary (scrap), and tertiary (re-mined) sources as well as the energy-intensive downstream processing. Focus is placed on materials science aspects, particularly on those that help reduce CO2 emissions, and less on process engineering or economy. The paper does not describe the devastating influence of metal-related greenhouse gas emissions on climate, but scientific approaches how to solve this problem, through research that can render metallurgy fossil-free. The content is considering only direct measures to metallurgical sustainability (production) and not indirect measures that materials leverage through their properties (strength, weight, longevity, functionality).

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“…As an efficient gas-based direct reduction reactor for ironmaking, the fluidized bed reactor can directly use iron ore fines of less than 5 mm, with the advantages of high gas-solid contact efficiency and rapid mass and heat transfer rates, resulting in exceptional metallurgical performance. Nowadays, with the transformation of raw iron ore from lump to powder, ironmaking via hydrogen-based fluidized bed direction reduction demonstrates more significant superiority and potential as one of the future's mainstream technologies for green and low-carbon ironmaking [8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Energy and Exergy Analysis of Hydrogen-Based Fluidized Bed Direct Reduction towards Efficient Fossil-Free Ironmaking

Du,

Liu,

Pan

et al. 2023

Processes

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Hydrogen-based fluidized bed direct reduction (H-FBDR) is an important and promising route for fossil-free ironmaking. In this study, to achieve the optimal operation state of energy use and exergy efficiency, the influences of the metallization process and the ratios of H2 injected on the energy and exergy flows in the H-FBDR process are studied. The results show that the thermodynamically designed two-stage reduction process (first: Fe2O3→FeO; second: FeO→Fe) requires a smaller H2 quantity than other metallization processes. According to the mass, energy, and exergy balance analyses, variations in the H2 consumption, exergy destruction, and energy/exergy losses of the overall system, iron ore preheater (F1), fluidized bed reactor system (R), heat exchanger (E), and gas preheater (F2) with different ratios of H2 injected (η) are derived. The total H2 consumption, total exergy destruction, and energy/exergy losses rise with increasing η, and sharp increases are observed from η = 1.3 to η = 1.8. The exergy efficiencies (φ) can be ranked as φR > φE > φF1 ≈ φF2, and the exergy destruction in components F1 and F2 is mainly caused by the combustion reaction, whereas physical exergy destruction dominates for components R and E. The performances of components F1, E, and F2 degrade from η = 1.0 to η = 1.8, and significant degradation arises when η exceeds 1.3. Thus, considering the H2 consumption, thermodynamic efficiency, and energy/exergy losses, the ratio of H2 injected should be set below 1.3. Notably, although the energy loss in the H-FBDR system is 2 GJ/h at η = 1.3, the exergy loss is only 360 MJ/h, in which the recycled gases from component E occupy 320 MJ/h, whereas the total exergy destruction is 900 MJ/h. Therefore, improving the performance of operation units, particularly the components F1 and F2, is as important as recovering the heat loss from component E for optimizing the H-FBDR process.

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Analysis of the Usability of Iron Ore Ultra-Fines for Hydrogen-Based Fluidized Bed Direct Reduction—A Review

Cited by 13 publications

References 82 publications

Dimensionless Number Group Analysis of Surface-Treated Powders

Dimensionless Number Group Analysis of Surface-Treated Powders

The Materials Science behind Sustainable Metals and Alloys

Energy and Exergy Analysis of Hydrogen-Based Fluidized Bed Direct Reduction towards Efficient Fossil-Free Ironmaking

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