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<p>A detailed, multi-scale mathematical model is developed for the gaseous reduction of iron ore pellets by H<sub>2</sub> and CO mixtures under time-dependent bulk temperature and gas composition. The model integrates intrinsic kinetics, intra-pellet diffusion, external transfer, and dynamic porosity evolution and is validated against 10 sets of experimental results simulating industrial blast furnace and MIDREX conditions. The model integrates intrinsic chemical reaction kinetics, intra-particle diffusion, external gas film transfer, and inter-phase heat transfer, while accounting for the dynamic structural evolution of the pellet porosity. Based on the grain model and Sohn’s law of additive reaction times, the model is formulated as a system of differential-algebraic equations and solved numerically. Its predictive capability was rigorously tested against a robust experimental database of 10 distinct reduction scenarios, encompassing reduction by pure H<sub>2</sub> and multicomponent H<sub>2</sub>/CO/CO<sub>2</sub>/N<sub>2</sub> mixtures under time-dependent bulk temperature and gas composition simulating industrial processes like the blast furnace shaft and the MIDREX process. The model demonstrates reliable accuracy, with an absolute error consistently below 0.1 in terms of the reduction degree. Analysis of the key dimensionless numbers (such as Nu, Sh, <i>σ</i><sup>2</sup>) confirmed the physical realism of the simulations, revealing a reaction regime influenced by both kinetics and diffusion, with intra-particle diffusion as the dominant mass transfer resistance. The successful validation over a wide range of conditions confirms the model’s robustness and its utility as a powerful tool for optimizing reduction processes and designing future hydrogen-based ironmaking technologies. Validation across all cases shows absolute errors of &lt;&#xa0;0.1, with dimensionless analysis (<i>σ</i><sup>2</sup>&#xa0;=&#xa0;0.49 to 1.4, Bi&#xa0;&lt;&#xa0;1) confirming the reaction to be in a mixed kinetics-diffusion regime.</p>

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A Computational Approach for the Reduction of Iron Ore Pellets by H2 + CO Mixtures Under Time-Dependent Bulk Temperature and Gas Composition

  • 期刊论文

  • 发表日期：

    2026年2月25日

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  • Bahador Abolpour,
  • Hong Yong Sohn

摘要

A detailed, multi-scale mathematical model is developed for the gaseous reduction of iron ore pellets by H2 and CO mixtures under time-dependent bulk temperature and gas composition. The model integrates intrinsic kinetics, intra-pellet diffusion, external transfer, and dynamic porosity evolution and is validated against 10 sets of experimental results simulating industrial blast furnace and MIDREX conditions. The model integrates intrinsic chemical reaction kinetics, intra-particle diffusion, external gas film transfer, and inter-phase heat transfer, while accounting for the dynamic structural evolution of the pellet porosity. Based on the grain model and Sohn’s law of additive reaction times, the model is formulated as a system of differential-algebraic equations and solved numerically. Its predictive capability was rigorously tested against a robust experimental database of 10 distinct reduction scenarios, encompassing reduction by pure H2 and multicomponent H2/CO/CO2/N2 mixtures under time-dependent bulk temperature and gas composition simulating industrial processes like the blast furnace shaft and the MIDREX process. The model demonstrates reliable accuracy, with an absolute error consistently below 0.1 in terms of the reduction degree. Analysis of the key dimensionless numbers (such as Nu, Sh, σ2) confirmed the physical realism of the simulations, revealing a reaction regime influenced by both kinetics and diffusion, with intra-particle diffusion as the dominant mass transfer resistance. The successful validation over a wide range of conditions confirms the model’s robustness and its utility as a powerful tool for optimizing reduction processes and designing future hydrogen-based ironmaking technologies. Validation across all cases shows absolute errors of < 0.1, with dimensionless analysis (σ2 = 0.49 to 1.4, Bi < 1) confirming the reaction to be in a mixed kinetics-diffusion regime.