Carbon Impact Mitigation of the Iron Ore Direct Reduction Process through Computer-Aided Optimization and Design Changes

Bechara, Rami; Hamadeh, Hamzeh; Mirgaux, Olivier; Patisson, Fabrice

doi:10.3390/met10030367

Cited by 20 publications

(15 citation statements)

References 21 publications

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“…Subsequently, Bechara et al [ 93 ] performed optimization to improve the DR plant performance in terms of CO 2 emissions. Like their previous work, they used a custom model in Aspen plus and modeled the DR plant operation, but this time they used a computer‐aided multivariable process optimization procedure offered in Aspen Plus instead of the simple manual optimization.…”

Section: Discussionmentioning

confidence: 99%

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

Ghadi

Radfar

Valipour

et al. 2023

steel research int.

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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.

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Section: Discussionmentioning

confidence: 99%

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

Ghadi

Radfar

Valipour

et al. 2023

steel research int.

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“…The outlet gas (syngas) consists of 51 mol.-% H2, 35 mol.-% CO, 8 mol.-% H2O, 1 mol.-% CH4 and 5 mol.-% CO2, which is in good agreement with literature values. 14,[29][30][31] The firebox operates with an excess air of 15% and maintains a thermodynamic temperature of greater than 1000 °C in the reforming section to facilitate the endothermic reforming reactions. To maximize the efficiency of the firebox, the combustion air is pre-heated to 500 °C against the flue gas before it enters the stack.…”

Section: Ch + H O → 3h + Comentioning

confidence: 99%

“…Higher excess ratios increase the chemical potential/driving force for the chemical reactions inside the shaft furnace; however, this increases the recycle stream and work associated with recompression. Typical top gas concentrations of the shaft furnace range from 33-49 mol.-% for H2, and 19-26 mol.-% for CO. [29][30][31] The temperature of the top gas leaving the shaft furnace ranges from 300-450 °C. 29,30,33 Thereafter, the top gas is quenched in a water scrubber to remove water produced by the iron ore reduction process as well as dust, and to lower the gas temperature for the recycle compressor.…”

Section: Dri Shaft Furnacementioning

confidence: 99%

“…Typical top gas concentrations of the shaft furnace range from 33-49 mol.-% for H2, and 19-26 mol.-% for CO. [29][30][31] The temperature of the top gas leaving the shaft furnace ranges from 300-450 °C. 29,30,33 Thereafter, the top gas is quenched in a water scrubber to remove water produced by the iron ore reduction process as well as dust, and to lower the gas temperature for the recycle compressor. About 1/3 of the top gas is sent to the reformer's firebox where it is burned.…”

Section: Dri Shaft Furnacementioning

confidence: 99%

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Green steel: design and cost analysis of hydrogen-based direct iron reduction

Rosner

Papadias

Brooks

et al. 2023

Preprint

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Hydrogen-based direct reduced iron (H2-DRI) is an alternative pathway for low-carbon steel production. Yet, the lack of established process and business models defining “green steel” make it difficult to understand what the respective H2 price has to be in order to be competitive with commercial state-of-the-art natural gas DRI. Given the importance of establishing break-even H2 prices and CO2 emission reduction potentials of H2-DRI, this study conducted techno-economic analyses of several design and operation scenarios for DRI systems. Results show that renewable H2 use in integrated DRI steel mills for both heating and the reduction of iron ore can reduce direct CO2 emissions by as much as 85%, but would require an H2 procurement cost of $1.63 per kg H2 or less. When using H2 only for iron ore reduction, economic viability is reached at an H2 procurement cost of $1.70 per kg, while achieving a CO2 emission reduction of 76% at the plant site. System design optimization strategies around excess H2 ratios in the DRI top gas and the H2 recycle pressurization can further improve performance and economics. Low H2 excess ratios are particularly attractive as they reduce pre-heating energy requirements and offer integration opportunities with static recycle ejectors if H2 is supplied at sufficiently high pressure. The potential of utilizing the EAF off-gas is shown to be much more synergistic with H2 DRI than NG DRI and can increase the break-even H2 procurement cost by up to 7¢ per kg H2. Such findings are critical for setting technical performance criteria for H2 supply and storage in the iron and steel sector.

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“…By conducting different simulations with different inlet gas compositions, they found that NG consumption and CO 2 emissions could be reduced by the setting of ratios H 2 /CO and (H 2 + CO)/(H 2 O + CO 2 ) at 1.23 and 12, respectively [23]. The same authors solved an optimization problem aiming to identify the values of a DR-NG-based process operating parameters to minimize the emissions generated [24]. Sarkar et al developed a DR-NG shaft thermochemical model to estimate the energy requirement and predict the emissions due to crude steel production, adopting an EAF.…”

Section: Literature Review Of Direct Reduction Iron Processesmentioning

confidence: 99%

An Economic Model to Assess Profitable Scenarios of EAF-Based Steelmaking Plants under Uncertain Conditions

et al. 2021

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The steelmaking processes are considered extremely energy-intensive and carbon-dependent processes. In 2018, it was estimated that the emissions from global steel production represented 7–9% of direct emissions generated by fossil fuels. It was estimated that a specific emissions value of 1.8 tCO2 per ton of steel was produced due to the carbon-dependent nature of the traditional blast furnace and basic oxygen furnace (BF-BOF) route. Therefore, it is necessary to find an alternative solution to the BF-BOF route for steel production to counteract this negative trend, resulting in being sustainable from an environmental and economic point of view. To this concern, the objective of this work consists of developing a total cost function to assess the economic convenience of steelmaking processes considering the variability of specific market conditions (i.e., iron ore price, scraps price, energy cost, etc.). To this purpose, a direct reduction (DR) process fueled with natural gas (NG) to feed an electric arc furnace (EAF) using recycled steel scrap was considered. The approach introduced is totally new; it enables practitioners, managers, and experts to conduct a preliminary economic assessment of innovative steelmaking solutions under market uncertainty. A numerical simulation has been conducted to evaluate the profitability of the investment considering the economic and environmental costs. It emerged that the investment is profitable in any case from an economic perspective. On the contrary, considering the environmental costs, the profitability of the investment is not guaranteed under certain circumstances.

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Carbon Impact Mitigation of the Iron Ore Direct Reduction Process through Computer-Aided Optimization and Design Changes

Cited by 20 publications

References 21 publications

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

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

Green steel: design and cost analysis of hydrogen-based direct iron reduction

An Economic Model to Assess Profitable Scenarios of EAF-Based Steelmaking Plants under Uncertain Conditions

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