Analysis of the Gaseous Reduction of Porous Wustite Pellets by Response Surface Methodology

Self Cite

Although the blast furnace process is the dominant ironmaking route to supply the feedstocks for steelmaking, a number of alternative ironmaking technologies such as the direct reduction process have grown rapidly in recent decades. This development is largely in response to the increasingly stringent emission control policies, rising costs of energy, and the increasing costs and environmental effects of coke usage. In direct reduction processes, iron oxides are reduced to iron at a temperature below its melting point. More than 79% of direct reduced iron is produced by Midrex and Energiron, both of which use gas‐based shaft furnaces. A proper understanding of these processes is required to improve the performance and operation of the plants based on them. Therefore, herein, it is aimed to provide a comprehensive review of research that is carried out over the last several decades to examine the effects of the important phenomena on the performance of the gas‐based shaft furnaces. The review is divided into experimental and mathematical investigations. The main features, limitations, and shortcomings of each study are discussed. Finally, the review concludes with current knowledge gaps and suggestions for further research in this thriving sector of the steel industry.

Section: Reactor Models Based On Porous-solid Modelmentioning

confidence: 99%

A Review on the Modeling of Direct Reduction of Iron Oxides in Gas‐Based Shaft Furnaces

Ghadi

Radfar

Valipour

et al. 2023

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“…First, from the perspective of reaction kinetics, the iron oxide reduction is the gas-solid interface reaction that can be described with the unreacted nuclear model (Figure 3a). [48,49] The diffusion of H 2 is easier than CO due to the molecular radius of H 2 . The reaction product (water) is smaller than that of CO and CO 2 , which means the reduction efficiency and thermal conductivity efficiency of H 2 is much higher than CO. Second, it can be seen from Figure 3b that the stable area of Fe expands with the increase in H 2 content.…”

Section: The Hydrogen-rich Gas Injection and Obf-carbonic Oxide Recyc...mentioning

confidence: 99%

The Low‐Carbon Production of Iron and Steel Industry Transition Process in China

Pang,

Bu,

Yuan

et al. 2023

Severe greenhouse gas emissions have made global warming one of humanity's most critical and intricate environmental challenges. As the world's largest producer and exporter of steel, China's steel industry contributes substantially to carbon emissions. The government formulated the policies and pathways to achieve carbon neutrality, and enterprises have proactively pursued low‐carbon technologies. In this review, the decarbonization process in the Chinese steel industry is classified into three stages according to the decarbonization amount and technological maturity: the improvements of the blast furnace‐basic oxygen furnace, the attempt of the nonblast furnace, and the preparatory electricity‐hydrogen coupling metallurgy. This article reviewed the industrial‐scale low‐carbon metallurgical technologies represented by the Baowu HyCORF process, bottom‐blowing O2‐CO2‐pulverized lime converter process, gas‐based direct reduction shaft furnace process, Molong HIsmelt process, and Ouye furnace process, as well as pointed out the development limitations of those processes. Additionally, the study presented prospects for zero‐carbon emission technologies coupling green energy generation and hydrogen metallurgy. These findings will offer substantial support for advancing research and development of low‐carbon metallurgical technologies and formulating relevant policies in the future.

“…Among these parameters, particular emphasis has been placed on the composition of H 2 [ 21 ] and CO [ 22 ] ; the mixture of gases (H 2 –CO, [ 23 ] H 2 –H 2 O, [ 24 ] H 2 –inert gas, [ 25 ] CO–CO 2 , [ 26 ] H 2 –CO–H 2 O–CO 2 [ 27 ] ); temperature variations spanning low (below 600 °C), [ 28 ] moderate (near to 600 °C), [ 21 ] and high (Over 600 °C) [ 29 ] ranges; pressure conditions [ 30 ] ; porosity levels [ 31 ] ; gangue content (SiO 2 , [ 32 ] CaO, [ 33 ] MnO, [ 34 ] CaCO 3 , [ 35 ] Al 2 O 3 [ 34 ] ); pellet radius [ 36 ] ; and volume flow rates. [ 21 ] Ghadi et al [ 37 ] identified particle size and pressure as the most influential parameters, whereas Cavaliere et al [ 38 ] emphasized the critical significance of temperature. Therefore, depending on the conditions, the importance of the parameters can be different.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Gaseous Reduction of Iron Oxide Pellets Using Machine Learning Algorithms, Explainable Artificial Intelligence, and Hyperparameter Optimization Techniques

Hosseinzadeh,

Kasiri,

Rezaei

2024

In this study, a novel application of machine learning (ML) is introduced to pellet modeling in the intricate non‐catalytic gas–solid reaction of direct reduction of iron oxide in the steel industry. Twenty ML models are developed using four algorithms: multilayer perceptron neural networks (MLPNN), radial basis function neural network (RBFNN), support vector regression, and random forest (RF). Hyperparameter optimization is conducted using Bayesian algorithms, random search, and grid search. The optimum model achieves a mean squared error test of 0.0052 with random RF for the larger dataset (872 samples), while smaller datasets (132, 225, and 242 samples) produce optimum models with MLPNN and RBFNN. Hyperparameters vary between the larger datasets and the smaller datasets. The models offer insight into the complex interactions among variables, including time, temperature, gas composition, hematite composition, pellet radius, and initial pellet porosity, influencing the metallization degree. In this study, the significant role of time and temperature is emphasized, as revealed by explainable artificial intelligence using Shapley additive explanation analysis that utilizes the game theory, and the effects of pellet modeling parameters are elucidated through 3D plots, particularly highlighting the impact of changing H2/CO proportion on metallization degree and carbon deposit.