Blast Furnace-basic Oxygen Furnace Research Articles

Pressurized Chemical Looping for Direct Reduced Iron Production: Economics of Carbon Neutral Process Configurations

The replacement of the blast furnace—basic oxygen furnace (BF-BOF) steelmaking route with the direct reduced iron—electric arc furnace (DRI-EAF) route reduces the direct CO2 emissions from steelmaking by up to 68%; however, the DRI shaft furnace is one of the largest remaining point source emitters in steelmaking. The capital and operating expenses of two potential nearly carbon-neutral DRI process configurations were investigated as a modification to a standard Midrex DRI facility. First, amine-based post-combustion capture with a 95% capture rate was considered as the benchmark, as it is currently commercially available. A second, novel configuration integrated the Midrex process with pressurized chemical looping—direct reduced iron (PCL-DRI) production. The capital expenditures were 71% and 28% higher than the standard Midrex process for a Midrex + amine capture plant, and a PCL-DRI plant, respectively. There was an incremental variable operating cost of USD 103 and USD 44 per tonne of CO2 for DRI production using amine capture and PCL-DRI, respectively. The amine capture configuration is most sensitive to the cost of steam generation, while PCL-DRI is more sensitive to the cost of electricity and the makeup oxygen carrier. An iron-based natural ore is recommended for PCL-DRI due to the low cost and availability. Based on the lower costs compared to amine-based post-combustion capture, PCL-DRI is an attractive means of eliminating CO2 emissions from DRI production.

Role of Exergy‐Based Process Evolution for Sustainable Steel Making: Rotary Hearth Furnace with Electric Arc Furnace Smelting

In conjunction with an electric arc furnace (EAF) process, a rotary hearth furnace (RHF) has emerged as a supplementary ironmaking unit to produce extra iron from iron‐bearing solid wastes from an integrated steel plant. Additionally, such units offer fuel‐switching options to low‐carbon input fuels. Exergy analysis is carried out for two variants of RHF, producing iron nuggets (ironmaking technology mark 3 process) or direct reduced iron (DRI; FASTMET process), involving cold/hot charging of DRI and scrap use in EAF. Process sustainability as characterized by higher exergy efficiency and lower CO2 emission has been analyzed for two variants of RHF‐EAF steelmaking systems, blast furnace‐basic oxygen furnace (BOF), scrap‐EAF, and COREX‐BOF process. Model‐based information for these parameters for RHF‐EAF process has been compared with other major steelmaking routes based on literature information. The RHF‐EAF process variants with some modification in process flow display better sustainability with relatively higher exergy efficiencies and low CO2 emissions as compared to other steelmaking processes and reasonably meet sustainable steelmaking process evolution criterion.

Comparing the decarbonization benefit provided by waste-based hydrogen routes to green steel production process: an analytical model

In the present context of global decarbonization, the steelmaking sector plays a key role. It is indeed one of the so-called hard-to-abate sectors. The high emissions from steelmaking depend on the use of the Blast Furnace-Basic Oxygen Furnace (BF-BOF) route, which generates 1.8 tCO2eq per ton of Liquid Steel (LS). The production of direct reduced iron (DRI) to power an electric arc furnace is currently the most adopted solution to achieve the decarbonization goals. This alternative, based on the use of natural gas, offers a decarbonization potential of about 34% compared to the BF-BOF route. The most promising alternative, however, consists of using electrolysis-based hydrogen (H2) to produce DRI. This solution would drastically reduce direct and indirect process emissions but requires a radical energy transition. In the current transition phase, waste-based H2 production routes could be attractive, but their potential need to be evaluated with respect to the steelmaking process. To this concern, the objective of the present work is to assess the decarbonization potential of three waste-based H2 production routes (i.e., gasification, incineration and anaerobic digestion-based) with respect to the electrolysis-based steelmaking route. An environmental analytical model was therefore developed to evaluate the total (i.e., direct, indirect, and avoided) greenhouse gases emissions associated with the production of 1 ton of LS by employing the different routes. A sensitivity analysis was also carried out to understand the benefit provided by each waste-based H2 alternative in the current energy transition phase. The results obtained confirmed the need for radical emission reductions from electricity generation to make electrolysis-based H2 production environmentally favorable and revealed a high decarbonization potential for waste-based routes in the current energy transition phase.

Research Progress on Iron- and Steelmaking Iste Slag-Based Glass-Ceramics: Preparation and GHG Emission Reduction Potentials

Promoted by carbon neutrality and solid iste policies, iron- and steelmaking iste slag (ISWS)-based glass-ceramics have drawn attention because of their contribution to achieving the net-zero carbon emissions goal for the iron- and steelmaking industry. However, a holistic estimation of the preparation, property and GHG (greenhouse gas) emission abatement of ISWS-based glass-ceramics is still under exploration. In this paper, research progress on preparing glass-ceramics from ISWS discharged from the traditional iron- and steelmaking industry is reviewed. Then, the influence of ISWS’s chemical characteristics on the preparation of glass-ceramics and the products’ performance are discussed. In addition, the potential of GHG emission reduction related to the promotion of ISWS-based glass-ceramics is measured. It is found that ISWS-based glass-ceramics can avoid 0.87–0.91 tons of CO2 emissions compared to primary resource routes. A scenario simulation is also conducted. If the technology could be fully applied in the ironmaking and steelmaking industries, the results suggest that 2.07 and 0.67 tons of indirect CO2 reductions can be achieved for each ton of crude steel production from blast furnace–basic oxygen furnace (BF-BOF) and electric arc furnace (EAF) routes, respectively. Finally, a “dual promotion” economic mode based on national policy orientation and the high demands on metallurgical iste slag (MWS)-based glass-ceramics is proposed, and the application prospects of MWS-based glass-ceramics are examined. These application prospects will deepen the fundamental understanding of glass-ceramic properties and enable them to be compounded with other functional materials in various new technologies.

The Options in Decarbonization Pathways for Malaysia

Abstract Two activities in Malaysia that emit large amounts of CO2 are electricity generation, and iron and steel production. To decarbonize the former, Malaysia should invest in a flexible energy system to overcome the intermittent characteristic of solar energy by influencing the pattern of demand with peak load pricing, increasing energy storage capability, and entering into a regional electricity grid arrangement. Malaysia should respond to the recent large capacity expansion in iron and steel production with blast furnace-basic oxygen furnace (BF-BOF) technology by ending immediately the issuance of new licenses for facilities that use this BF-BOF technology, and speed up the process of adopting advanced green, near-zero emission technologies (e.g., Hydrogen Breakthrough Ironmaking Technology [HYBRIT]), by applying for foreign technical assistance (e.g., the United Nations Climate Technology Center and Networks [UN-CTCN]) and for concessionary climate finance under the Paris Agreement. Finally, to be consistent with the 1.5°C pathway for the world, Malaysia should aim to commit to achieve peak carbon emissions by 2030 and net zero emissions by 2050.

Steel, Aluminum, and FRP-Composites: The Race to Zero Carbon Emissions

As various regions around the world implement carbon taxes, we assert that the competitiveness of steel products in the marketplace will shift according to individual manufacturers’ ability to reduce CO2 emissions as measured by cradle-to-gate Life Cycle Analysis (LCA). This study was performed by using LCA and cost estimate research to compare the CO2 emissions and the additional cost applied to the production of various decarbonized materials used in sheet for automotive industry applications using the bending stiffness-based weight reduction factor. The pre-pandemic year 2019 was used as a baseline for cost estimates. This paper discusses the future cost scenarios based on carbon taxes and hydrogen cost. The pathways to decarbonize steel and alternative materials such as aluminum and reinforced polymer composites were evaluated. Normalized global warming potential (nGWP) estimates were calculated assuming inputs from the current USA electricity grid, and a hypothetical renewables-based grid. For a current electricity grid mix in the US (with 61% fossil fuels, 19% nuclear, 20% renewables), the lowest nGWP was found to be secondary aluminum and 100% recycled scrap melting of steel. This is followed by the natural gas Direct Reduced Iron–Electric Arc Furnace (DRI-EAF) route with carbon capture and the Blast Furnace-Basic Oxygen Furnace (BF-BOF) route with carbon capture. From the cost point of view, the current cheapest decarbonized production route is natural gas DRI-EAF with Carbon Capture and Storage (CCS). For a renewable electricity grid (50% solar photovoltaic and 50% wind), the lowest GWP was found to be 100% recycled scrap melting of steel and secondary aluminum. This is followed by the hydrogen-based DRI-EAF route and natural gas DRI-EAF with carbon capture. The results indicate that, when applying technologies available today, decarbonized steel will remain competitive, at least in the context of automotive sheet selection compared to aluminum and composites.

Cost and life cycle analysis for deep CO2 emissions reduction of steelmaking: Blast furnace-basic oxygen furnace and electric arc furnace technologies

Iron and steel manufacturing is the largest contributor to CO2 emissions among heavy industries worldwide. This is mostly due to the use of coal in blast furnace-basic oxygen furnace (BF-BOF) process for virgin (primary) steel production. The electricity generation mix used in the electric arc furnace (EAF) process to recycle scrap steel also contributes to the CO2 emission associated with secondary steel production. To decarbonize iron and steel sector, we investigated decarbonization options for BF-BOF and EAF processes, including energy efficiency, carbon capture and storage, and the use of clean energy sources, in various BF-BOF and EAF process configurations. For each decarbonization approach, we evaluated the CO2 reduction potential via life cycle analysis (LCA) and estimated the associated cost through techno-economic analysis (TEA). A typical U.S. BF-BOF for virgin steel production has a cradle-to-gate (CTG) CO2 emissions of 1,990 kg/MT steel with a levelized cost of steel (LCOS) of $439/MT steel, while a typical U.S. EAF process for secondary steel production in the United States has a CTG CO2 emissions of 270 kg/MT steel with a LCOS of $365/MT steel. Combining renewable energy sources and carbon capture, BF-BOF CTG CO2 emissions can be reduced to 16 kg/MT steel, and EAF configurations can achieve similar deep reductions to reach 25 kg/MT steel. The corresponding LCOS with these decarbonization levels is estimated to increase to $542/MT steel and $348/MT steel, respectively. The estimated CO2 avoidance costs vary from -$90/MT CO2 to $646/MT CO2, depending on the various decarbonization technologies and energy prices.

Multi-process production occurs in the iron and steel industry, supporting ‘dual carbon’ target: An in-depth study of CO2 emissions from different processes

Reducing CO2 emissions of the iron and steel industry, a typical heavy CO2-emitting sector, is the only way that must be passed to achieve the ‘dual-carbon’ goal, especially in China. In previous studies, however, it is still unknown what is the difference between blast furnace-basic oxygen furnace (BF-BOF), scrap-electric furnace (scrap-EF) and hydrogen metallurgy process. The quantitative research on the key factors affecting CO2 emissions is insufficient. There is also a lack of research on the prediction of CO2 emissions by adjusting industrial structure. Based on material flow analysis, this study establishes carbon flow diagrams of three processes, and then analyze the key factors affecting CO2 emissions. CO2 emissions of the iron and steel industry in the future is predicted by adjusting industrial structure. The results show that: (1) The CO2 emissions of BF-BOF, scrap-EF and hydrogen metallurgy process in a site are 1417.26, 542.93 and 1166.52 kg, respectively. (2) By increasing pellet ratio in blast furnace, scrap ratio in electric furnace, etc., can effectively reduce CO2 emissions. (3) Reducing the crude steel output is the most effective CO2 reduction measure. There is still 5.15 × 108-6.17 × 108 tons of CO2 that needs to be reduced by additional measures.

Towards fossil-free steel: Life cycle assessment of biosyngas-based direct reduced iron (DRI) production process

Given the urgent need for transitions towards global net zero emissions, decarbonisation of the iron and steel industry is critical. Deep decarbonising this sector requires a breakaway from current blast furnace-basic oxygen furnace (BF-BOF) technologies that largely depend on fossil resources. Biosyngas is considered to be a promising alternative to fossil energy and reductants used in existing ironmaking due to its renewability, technological maturity and compatibility for use in existing furnaces. The present work assesses the environmental impacts of biosyngas-based direct reduced iron production followed by electric arc furnace (DRI-EAF) routes for crude steel production. Further, the proposed routes are compared with the other steelmaking routes, including BF-BOF, natural gas (NG)-based and hydrogen-based direct reduction routes by performing life cycle assessment (LCA). The results indicate that the global warming potential (GWP) value for the biosyngas-based DRI-EAF system is 75% lower than the existing NG-based DRI-EAF route and 85% lower than the BF-BOF route. Moreover, the proposed system possibly has lower GWP values than the renewable hydrogen-based DRI-EAF route. The proposed system has an estimated cradle-to-gate GWP of 251 kg CO2 eq./t crude steel, of which 80% is from upstream emissions. Combined with CO2 storage, the GWP of the proposed system is a net negative, estimated at −845 kg CO2 eq./t crude steel for the selected system boundary. In addition to GWP, other non-climate impact indicators are also evaluated to identify potential burden shifting. The results highlight the emissions reduction potential of the novel biosyngas DRI production route. Large-scale deployment, however, requires sustainable forest management and adequate CCS infrastructure, along with a strong, long-term policy framework to incentivise the transitions.

Cost effective decarbonisation of blast furnace – basic oxygen furnace steel production through thermochemical sector coupling

We present here a first-principles study of the sector coupling between a thermochemical carbon dioxide (CO2) splitting cycle and existing blast furnace – basic oxygen furnace (BF-BOF) steel making for cost-effective decarbonisation. A double perovskite, Ba2Ca0.66Nb0.34FeO6, is proposed for the thermochemical splitting of CO2, a viable candidate due to its low reaction temperatures, high carbon monoxide (CO) yields, and 100% selectivity towards CO. The CO produced by the TC cycle replaces expensive metallurgical coke for the reduction of iron ore to metallic iron in the blast furnace (BF). The CO2 produced from the BF is used in the TC cycle to produce more CO, therefore creating a closed carbon loop, allowing for the decoupling of steel production from greenhouse gas emissions. Techno-economic analysis of the implementation of this system in UK BF-BOFs could reduce steel sector emissions by 88% while increasing the cost-competitiveness of UK steel on the global market through cost reduction. After five years, this system would save the UK steel industry £1.28 billion while reducing UK-wide emissions by 2.9%. Implementation of this system in the world's BF-BOFs could allow the steel sector to decarbonise in line with the Paris Climate Agreement to limit warming to 1.5 °C.

Integration of carbon capture technologies in blast furnace based steel making: A comprehensive and systematic review

Decarbonization of the iron and steel industry, which accounts for 7–9% of global annual emissions, is a strategic objective to achieve carbon emissions reduction targets in line with climate change policies, while maintaining economic competitiveness. Carbon capture (CC) technologies are of critical importance to achieve these goals. This work presents the first systematic review of the integration of CC technologies in the blast furnace-basic oxygen furnace (BF-BOF) steelmaking route, which is expected to maintain a dominant market share over the coming decades. Integration options for post-combustion, looping cycles, oxy-combustion and pre-combustion are described and compared in terms of energy penalty, carbon emissions abatement potential, cost, technology readiness level, and practical deployment considerations. The review yielded 188 studies from peer-reviewed articles and technical papers. Research is mainly focused on chemical absorption, physical adsorption, and oxy-blast furnace technologies, but other carbon capture methods including calcium looping, Sorption Enhanced Water Gas Shift, and membranes appear promising in terms of cost and carbon emission reduction. This article provides an in-depth analysis of the current state of the art and crucial considerations for future decision making in the techno-economic selection and integration of CC technologies. Barriers to overcome for practical implementation are also identified and discussed in this article.

A Comprehensive Review of Secondary Carbon Bio-Carriers for Application in Metallurgical Processes: Utilization of Torrefied Biomass in Steel Production

This review aims to show the significance of the use of secondary carbon bio-carriers for iron and steel production. The term ‘secondary carbon bio-carriers’ in this review paper refers to biomass, torrefied biomass, biochar, charcoal, or biocoke. The main focus is on torrefied biomass, which can act as a carbon source for partial or complete replacement of fossil fuel in various metallurgical processes. The material requirements for the use of secondary carbon bio-carriers in different metallurgical processes are systematized, and pathways for the use of secondary carbon bio-carriers in four main routes of steel production are described; namely, blast furnace/basic oxygen furnace (BF/BOF), melting of scrap in electric arc furnace (scrap/EAF), direct reduced iron/electric arc furnace (DRI/EAF), and smelting reduction/basic oxygen furnace (SR/BOF). In addition, there is also a focus on the use of secondary carbon bio-carriers in a submerged arc furnace (SAF) for ferroalloy production. The issue of using secondary carbon bio-carriers is specific and individual, depending on the chosen process. However, the most promising ways to use secondary carbon bio-carriers are determined in scrap/EAF, DRI/EAF, SR/BOF, and SAF. Finally, the main priority of future research is the establishment of optimal parameters, material quantities, and qualities for using secondary carbon bio-carriers in metallurgical processes.

Assessment of a multistep revamping methodology for cleaner steel production

A novel revamping methodology is proposed to achieve the decarbonization of currently operating integrated steel mills (step 0) without reducing steel production levels. Such a method encompasses four successive steps involving cleaner and more energy efficient technological pathways for steel production.The decarbonization strategy is reported: step 1, partial replacement of coke with recycled plastic in a conventional Blast Furnace – Basic Oxygen Furnace (BF-BOF) plant; step 2, implementation of a Direct Reduction-Electric Arc Furnace (DR-EAF) line combined with the BF-BOF plant; step 3, complete shut-down of the BF-BOF line and full operation of two DR-EAF lines fed by CH4; step 4, installation of an alkaline electrolyzer and use of 100% green H2 as a reducing agent in the DR plants.The gradual replacement of the integrated steel mill with DR-EAF lines causes a progressive drop in CO2 emissions, ranging from 8.5 Mt/y at step 0 to a minimum of 0.68 Mt/y at step 4 (92% decrease).Coke replacement with recycled plastic in the blast furnace in step 1 leads to a slight decrease in CO2 emissions without altering the structural layout of the plant. In step 2, the combined operation of BF-BOF and DR-EAF lines determines a 39% decrease in CO2 emission compared to the initial configuration, while keeping total steel production constant. Step 3 involves two DR-EAF lines fed by CH4 and reduces the CO2 emissions by 75% compared to the initial configuration. The operation of two DR-EAF lines increases the electricity consumption, especially when 100% green H2 is involved as a reducing agent in step 4. By increasing the scrap mass fraction in the EAFs of step 4, both electricity and H2 demands of the DR plant are expected to decrease, while the CO2 emission levels remain almost unchanged, leading to about 92% total CO2 emissions reduction compared to the initial configuration (provided that green electricity is used). By assuming an initial 10% scrap mass fraction at the EAFs inlet of step 4, the demand of green hydrogen is significant, thus requiring the installation of a 1.42 GW electrolyzer. The capital expenditure (CAPEX) estimated upon completion of the revamping methodology amounts to approximately 2.97 B€. The transition towards a full decarbonization of steel production technologies is demonstrated to be technically feasible, though strictly dependent upon the large availability of low emissions electric power and scrap material.

Effect of hot metal charging on economic and environmental indices of electric arc furnace steelmaking in China

Hot metal (HM) charging electric arc furnaces (EAF) with good production indices and economic benefits have been widely used in China. In this study, the economic and environmental indices of EAF were analyzed based on a mechanistic process model, and the energy consumption, carbon emissions, and production costs with different hot metal ratios (HMRs) were obtained. There are strong correlations between HMR and the energy consumption, carbon emissions, and production costs of EAF. The Pareto optimal solution for the current state is 50% HMR-EAF, which produces carbon emissions of 1402.68 kg-CO2/t and a production cost of 3609.40 CNY/t. Considering the current situation in China, this process is more in line with the need to coordinate the economic and environmental indices of steel plants compared to direct reduced iron (DRI)-EAF, scrap-EAF, and blast furnace-basic oxygen furnace (BF-BOF) processes. Moreover, it has the potential to be more easily realized and promoted.

CO2 accounting model and carbon reduction analysis of iron and steel plants based on intra- and inter-process carbon metabolism

Carbon emission accounting for iron and steel plants (ISPs) is crucial to formulate prospective low-carbon strategies. In this study, a CO 2 emission accounting model for an ISP that accounts both direct and indirect emissions is proposed. Especially, the proposed model considers the effect of the by-product gases of steel production on the intra- and inter-process carbon metabolism. For a comprehensive evaluation of the carbon emission level of an ISP, direct emissions are correspondingly categorized into process direct emissions (PDE) or combustion direct emissions (CDE), and as for indirect emissions, purchased electricity indirect emissions (EIE) and purchased coke indirect emissions (CIE) were considered. Subsequently, a case study is performed with the proposed model by calculating the CO 2 emissions of an ISP using both the blast furnace-basic oxygen furnace (BF-BOF) and electric arc furnace (EAF) routes. The results show that the CO 2 emissions of the ISP reach 1971.63 kg/t-cs, whereas the PDE of the BF process is 496.09 kg/t-cs, which is the bottleneck of carbon reduction. Furthermore, a top gas recycling-oxygen blast furnace (TGR-OBF) process-based integrated steelmaking process is built to analyse the possible carbon reduction potential. A comparison of the proposed TGR-OBF with traditional BF route reveals that a carbon reduction of 45.39% can be achieved with the TRG-OBF route. In addition, the effects of scrap rate and proportion of electricity generated from alternative energy on the carbon emissions of EAF is discussed. To reduce the EIE in ISPs, measures to optimise the power supplying structure should be considered. Scenario analysis indicates that by improving the efficiency of power generation of on-site power plants (OPPs) and increasing the application of waste energy recovery technology (WERT), EIE can be reduced by 44.49%. • A CO 2 accounting model was proposed based on process carbon metabolism. • By-product gases are key to the carbon metabolism for iron and steel making. • The application of TGR-OBF can significantly reduce the PDE of ironmaking production. • Improving the efficiency of OPP and increasing the application of WERT can reduce EIE.

Quantifying the energy saving potential and environmental benefit of hydrogen-based steelmaking process: Status and future prospect

The application of hydrogen is considered to be an effectiveg way for decarbonising the iron and steel industry. This research aims to quantifying the energy saving potential and environmental benefit of two hydrogen-based steelmaking processes through exergy analysis and life cycle assessment: hydrogen-enriched shaft furnace-electric furnace (HESE) process based on coal gasification and hydrogen shaft furnace-electric furnace (HSE) process based on water electrolysis. It is estimated that the energy consumption and CO2 emission of the HESE process are 11.82 GJ/t and 1121.28 kg/t, achieving a 39.79% of energy-saving and a 45.42% of CO2 emission-reduction when compared with the blast furnace-basic oxygen furnace (BF-BOF) process. The research goes further to evaluate the future HSE process of its energy saving potential and environmental benefit. When renewable electricity is applied, the HSE process will have relatively low carbon emission (i.e. 120.92 kg). However, the energy consumption reaches 13.42 GJ with an exergy efficiency of 33.91%. A key feature of the process lies in the power consumption, which can be balanced through the share of scrap used, and its future links with the prosperity of hydrogen economy. The present work should do helpful effort to the carbon neutral goal of iron and steel industry.

Assessment of economic, energy and ecological efficiency of iron and steel production from orecoal briquettes in electric-furnace melting facility with application of hydrogen fuel

According to the Russia National cadastre, emissions of carbon dioxide in the steel industry in 2019 in the sector “Industrial emissions” accounted for near 50% of the whole volume of its emissions in the whole country’s industry. A perspective way to decrease emissions of greenhouse gases is application of hydrogen in technological processes of metallurgical stuff production. A brief characteristic of basic technologies of hydrogen production presented. Concept of hydrogen technology development in steel industry of Russia stated, basic directions of metallurgical subindustries restructing related to implementation of the new fuel – “brown” hydrogen presented. Possibilities of “brown” hydrogen obtaining as a secondary energy resource of metallurgical production considered. Results of calculation of economic, energy and ecological effectiveness of cast iron, steel and “brown” hydrogen production in electric-furnace melting facilities of new type presented. It was shown that replacement of scheme “blast furnace-basic oxygen furnace”, including production of sinter and coke, by electric-furnace melting production with obtaining hot metal and steel from ore-coal briquettes and application of “brown” hydrogen and recycling of carbon dioxide enables to exclude greenhouse gases emissions. Capital investment into the hydrogen project of 1.0 million t/year capacity with restructing production capacities will account for 9.5 billion Rubles (120.0 million euro), economical effect – 5.4 billion Rubles (70.0 million euro), period of capital investments payback – 1.8 year.

Carbon footprint of scenarios towards climate-neutral steel according to ISO 14067

Within this paper, new findings of the potential of four considered intermediate solutions towards a primary climate-neutral steel production are reported. (1) Injection of natural gas into a blast furnace, (2) injection of hydrogen into a blast furnace, (3) natural gas-based direct reduction with subsequent input of the hot briquetted iron (HBI) in a blast furnace, and (4) hydrogen-based direct reduction with subsequent input of the hot briquetted iron in a blast furnace.The current study is a carbon footprint assessment applied to the product hot-rolled coil (HRC) according to the ISO norm 14067:2019. A cradle to gate approach is used including the production of raw materials to the production of hot-rolled coil. To define a reference point, a carbon footprint of hot-rolled coil produced via a typical blast furnace – basic oxygen furnace (BF-BOF) route is presented. The basic data set is based on primary data from the integrated site of thyssenkrupp Steel Europe AG (tkSE), year 2018. Within a novel approach, this base line is enhanced by integrating metallurgical models from the literature. Thereby all changes of the complex material and energy supply chain of an integrated site and of the upstream chain are reported. The carbon footprint of each process unit is presented in detail so that optimization potentials are identified, which impacts are analysed within a sensitivity analysis. A holistic comparison of using hydrogen in a blast furnace to using hydrogen in a direct reduction plant is presented and delivers important findings. This can help steel producers to maximize the efficiency of hydrogen use.Since the focus of this paper lies on the comparison of steel production routes and the assessments for all considered scenarios are based on the same methodologies and databases the sensitivity of made assumptions on the deltas between these scenarios is much weakened than the sensitivity of absolute values. That's one of the reasons why, the conclusions of this paper, which are referred to the plant of tkSE, can be transferred to other production sites, as well. The presented results can help decision-makers to know the potentials of possible intermediate solutions towards a climate-neutral steel production and how the potentials can be maximized.The carbon footprint of the product hot-rolled coil is 2.1 t CO2eq/tHRC following the recycled content approach and 0.82 t CO2eq/tHRC following the end-of-life recycling approach. The reduction potential for the carbon footprint is about 4 % for injecting natural gas into a blast furnace and about 9 % for injecting hydrogen into a blast furnace. The hydrogen is produced via electrolysis driven by a renewable German energy mix, year 2018. Using hot briquetted iron (HBI) within a blast furnace leads to a reduction potential between 5 % and 12 % for natural gas based-HBI and between 10 % and 17 % for H2-based HBI. The reduction potential strongly depends on the iron feedstock, which is replaced by the hot briquetted iron. Between 4.5 and 7.0 kg CO2eq/kg H2 are avoided by injecting hydrogen into a blast furnace, and about 5.4 kg CO2eq/kg H2 are prevented if the hydrogen is injected into a direct reduction plant.

Driving investments in ore beneficiation and scrap upgrading to meet an increased demand from the direct reduction-EAF route

The pressure on the steel industry to reduce its carbon footprint has led to discussions to replace coke as the main reductant for iron ore and turn to natural gas, bio-syngas or hydrogen. Such a major transition from the blast furnace-basic oxygen furnace route, to the direct reduction-electric arc furnace route, for steel production would drastically increase the demand for both suitable iron ore pellets and high-quality scrap. The value for an EAF plant to reduce the SiO2 content in DRI by 2 percentage points and the dirt content of scrap by 0.3 percentage points Si was estimated by using the optimization and calculation tool RAWMATMIX®. Three plant types were studied: (i) an integrated plant using internal scrap, (ii) a plant using equal amounts of scrap and DRI and (iii) a plant using a smaller fraction of DRI in relation to the scrap amount. Also, the slag volume for each plant type was studied. Finally, the cost for upgrading was estimated based on using mainly heuristic values. A conservative estimation of the benefit of decreasing the silica content in DRI from 4 to 2% is 20 USD/t DRI or 15 USD/t DR pellets and a conservative figure for the benefit of decreasing the dirt in scrap by 0.3 percentage points Si is 9 USD/t scrap. An estimate on the costs for the necessary ore beneficiation is 2.5 USD/t pellet concentrate and for a scrap upgrade, it is 1-2 USD/t scrap.

Low-carbon production of iron and steel: Technology options, economic assessment, and policy

Summary Given increased urgency to transition the global economy to net-zero CO2 emission, governments and industry have increased focus on decarbonizing hard-to-abate sectors, including steel making, which contributes roughly 6% of global CO2 emission and 8% of energy-related emission (including power consumption emission). This paper reviews current global iron and steel production and assesses available decarbonization technologies, including hydrogen injection, solid biomass substitution, zero-C electricity substitution, carbon capture and storage (CCS) retrofit, and combinations of these decarbonization approaches. Blast furnace-basic oxygen furnace (BF-BOF) dominates production (71%) and is particularly stubborn to any decarbonization technology. Direct reduced iron to electric arc furnace (DRI-EAF) production is 5% and growing, it appears to have better decarbonization potential to move toward net-zero. Secondary steel production using mainly steel scrap in electric arc furnace (EAF-scrap) is 24% of global production and has both the lowest energy consumption and is technically simplest to decarbonize through electrification but is limited in market share to recycled steel capacity. Of the options assessed, blue hydrogen, carbon neutral biomass, and CCS appear to have the lowest cost and highest technical maturity. However, no single approach today can deliver deep decarbonization to the iron and steel industry and all approaches lead to substantial production cost increase. No uniform ideal solution exists, and different geographies, infrastructure, and economies will determine the local optimum solution with viability and cost. Policy measures will be required to provide financial incentives for decarbonization and to avoid unwelcome outcomes such as emissions leakage or job loss.