Development of a Porous Solid Model for the Direct Reduction of Iron Ore Pellets

Fradet, Quentin; Ali, Mohammed Liaket; Riedel, Uwe

doi:10.1002/srin.202200042

Cited by 12 publications

(4 citation statements)

References 20 publications

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“…This is due to the fact that the transport of reactants and reactions by‐products is slower with respect to the chemical reactions. [ 29,30 ]…”

Section: Introductionmentioning

confidence: 99%

“…This is due to the fact that the transport of reactants and reactions by-products is slower with respect to the chemical reactions. [29,30] Here, the effective diffusion coefficient is influenced by the gas physical properties and by the temperature. As both temperature and hydrogen content are increased, the diffusion coefficient increases.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Cavaliere

Perrone

Marsano

et al. 2023

steel research int.

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The present study deals with the analyses of the direct reduction kinetics during the hydrogen reduction of industrial iron oxide pellets. Various types of pellets with different percentage of total iron content and metal oxides are examined. They are reduced at different temperatures and pressure (700–1100 °C and 1–6 bar) in hydrogen atmosphere. The reduction behavior is described in terms of time to reduction, rate of reduction, and kinetics constant. All the obtained results are analyzed through the employment of a commercial multiobjective optimization tool to precisely define the weight that each single parameter has on the reduction behavior. It is shown that from the point of view of the processing conditions, temperature is the main factor influencing the time to total reduction. From the point of view of the pellets properties, it is mainly influenced by the total iron percentage and then by porosity and basicity index. Also, the kinetics behavior is largely influenced by the reduction temperature even if it is mainly governed by the porosity and pores size from the point of view of the reduced pellets. The reduction rate is also mainly influenced by temperature and then by iron percentage, gas pressure, basicity index, and porosity.

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“…This is due to the fact that the transport of reactants and reactions by‐products is slower with respect to the chemical reactions. [ 29,30 ]…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Cavaliere

Perrone

Marsano

et al. 2023

steel research int.

View full text Add to dashboard Cite

show abstract

“…The detailed mathematical expressions and derivations of our model are discussed in another article. [ 13 ] This article gives further insights into the solution of the gas species concentrations and solid mole fractions along the pellet radius, assuming spherical symmetry.…”

Section: Kinetics and Thermodynamic Models Of Gaseous Iron Oxide Redu...mentioning

confidence: 99%

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres

Ali

Fradet

Riedel

2022

steel research int.

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The steel industry currently faces significant challenges. These are enormous environmental impacts, material usage, energy consumption, and byproducts of the processes. [1] In 2020, the total crude steel production was 1869 million tons (Mt). [2] The conventional blast furnace-basic oxygen furnace (BF-BOF) route produces 70% of the global crude steel, [3] utilizing coke to produce iron by reducing iron ore, which emits high amounts of CO 2 in the environment. Steel production contributed 6.7% of the global anthropogenic emissions of CO 2 in 2020, and the average emission is estimated to be 1.8 t CO 2 / per t steel. [4] This corresponds to %3.46 Gt CO 2 per year, eventually leading to even higher annual emissions in 2050 due to the growing steel demand. Given this high level of CO 2 emissions, steel production cannot rely on continuous process optimization but instead, needs fundamental technological changes to meet future emission limitations.Under these circumstances, the direct reduction (DR) process of iron oxide is a promising technology to reduce the CO 2 emissions where hematite (Fe 2 O 3 ) is reduced by syngas (H 2 /CO-mixture) or even with pure hydrogen (H 2 ). Many mathematical models have been proposed in the literature to predict the gaseous reduction behavior of iron oxide. However, due to a large number of influencing factors in the direct reduction process, for example, gas composition, operating pressure, temperature, or solid material characteristics (porosity, tortuosity, grain size, gangue contents, mineralogy, etc.), uncertainty is relatively high. Researchers usually try to balance between model simplicity and accuracy (agreement with experimental data). To avoid the inherent complexity of the direct reduction process, McKewan [5] developed a simple one-interface shrinking core model by considering the interface chemical reaction as the rate-limiting step. They concluded while validating against their data that diffusion and chemical reaction should be considered simultaneously. Tsay et al. [6] developed a model based on a three-interface shrinking core model for H 2 /CO mixtures, considering the same diffusivities and mass transfers for reactants and products. However, this approach has the evident weakness of assuming a distinct sharp interface between different solid oxides. A transient isothermal model based on the grain model has been proposed by Valipour et al. [7] to simulate a porous hematite pellet's thermal and kinetic behavior in a syngas environment. They showed how models not considering the film resistances deviate systematically from the experimental data.Aside from the fundamental mathematical approach, the chemical kinetics of reduction of iron oxide with H 2 /CO mixtures has not been adequately investigated, especially the carbon deposition phenomena. Turkdogan et al. [8] studied the kinetics of direct reduction process of iron oxide using hydrogen. They found out that the transformation process of hematite to iron is mediated by magnetite (Fe 3 O 4 ) and wüstite (Fe (1Ày) O).

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“…The chemical reaction rates are also largely influenced by the local concentration of reducing gases at the interface as well as by the type of iron oxide that should be reduced [35].…”

Section: Introductionmentioning

confidence: 99%

Critical analysis of variable atmosphere gaseous reduction of iron oxides pellets

Cavaliere

Perrone

Marsano

2023

Ironmaking & Steelmaking

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The paper deals with the analyses of the direct reduction kinetics of industrial iron oxide pellets. Various types of pellets were reduced at different temperatures and pressure (700-1100°C and 1-6 bar) in various atmospheres with different contents of hydrogen and carbon monoxide. The reduction behaviour was described in terms of time to reduction, rate of reduction, and kinetics constant. For those pellets reduced in presence of carbon monoxide, also the carbon percentage in the reduced pellets was taken into account. All the obtained results were analysed through the employment of a commercial multi-objective optimisation tool (modeFrontier) in order to precisely define the weight that each single parameter has on the reduction behaviour of the pellets. The performed analyses allowed also to correlate the different processing parameters and the pellets properties in order to define the kinetics conditions as well as the factors limiting the reduction process.

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Development of a Porous Solid Model for the Direct Reduction of Iron Ore Pellets

Cited by 12 publications

References 20 publications

Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres

Critical analysis of variable atmosphere gaseous reduction of iron oxides pellets

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Development of a Porous Solid Model for the Direct Reduction of Iron Ore Pellets

Cited by 12 publications

References 20 publications

Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Hydrogen‐Based Direct Reduction of Iron Oxides Pellets Modeling

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H2/CO Atmospheres

Critical analysis of variable atmosphere gaseous reduction of iron oxides pellets

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Product

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Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres