This article discusses the transition stage, which is the last stage before the green end stage. The transition stage involves upgrading the technology of existing integrated steel plants to low-carbon technology to reduce emissions by up to 80%. However, the realistic estimate is between 50-60%. Upgrading existing integrated steel plants with low-carbon technology is a necessary step in reducing CO2 emissions, as there are still many integrated steel plants and they will be operational for decades to come. This is not a long-term solution, but it is important to increase low-carbon technologies in medium term until the technology, economics and infrastructure required to support steelmaking in the green end state are available. As the efficiency of blast furnaces improves, the use of exhaust gases in on-site power generation will decrease. This leads to the need to bring electricity from the grid. For this reason, the use of renewable energy sources is required to reach the full potential of these technologies. (Ellis & Bao 2020)
New technology needs to be introduced at a rapid pace, which is also supported by new infrastructure. The transition to larger scrap-based steel plants is only possible when the availability of scrap increases. This also involves replacing BF/BOF production with scrap based EAF production. Switching to electric arc furnaces will not be simple, but necessary if the near-zero stage in the steel industry is to be achieved. (Hoffman et al. 2020)
The transition stage strongly involves the utilization of new technologies. One example of this is hydrogen based DRI and EAF production. In this process green hydrogen based DRI and scrap are used in conjunction with EAF. The process replaces fossil fuels in the DRI production phase with hydrogen produced from renewable energy. This production method is technically proven and enables almost emission free steel production. (Hoffman et al. 2020) According to IEA, one hydrogen based DRI plant per month is required globally to replace BF/BOF production when the technology is commercially available. This means that the electricity demand will increase by 720 terawatt hours by 2050, equivalent to 60 percent of the industry’s current electricity consumption. (IEA 2020)
Carbon capture utilization and storage (CCUS) will also play a major role in the steel industry’s decarbonization during the transition stage. CCUS uses emissions to create new products such as ammonia or bioethanol. At best, CCUS can reduce the emission intensity of an integrated steelmaking process by up to 60%. Currently, carbon capture and usage is still in development and has not been economically proven. However, these problems are expected to be resolved in the coming decades and after that the CCUS system can be introduced in the steel industry as well as in other sectors. (Ellis & Bao 2020) According to the IEA, the simultaneous deployment of CCUS systems with hydrogen based DRI plants will require approximately 0.4 Gt of CO2 capture globally in 2050, equivalent to the deployment of a large CCUS facility every 2-3 weeks from 2030 onwards (IEA 2020).
Biomass can be used in integrated steelmaking as a source of fuel or reductant, replacing coal or other fuels, for example, in the sintering process or as a source of carbon in the steelmaking process (Ellis & Bao 2020). The application of fossil fuels, such as coal and coal derived coke in iron ore processing and steelmaking, contributes to 20 % of total global industrial fossil fuel consumption (Abdelazis et al. 2011). Replacing this amount with biomass would significantly reduce the emission intensity. Biochar, made from biomass, is a renewable fuel source which can be used as an alternative to coal and coke in steelmaking. In addition, research results have shown that biochar has the potential to find its place in coking, sintering, metalized pellets production and as a carbon source in BF and EAF processes (Ye et al. 2019). EAF, just like BF, uses coke and anthracite coal as fuel source, slag foaming agent and steel recarburizer. Therefore, the potential of using biochar from renewable sources will further help to reduce the carbon emissions of EAF steelmaking. Luxmet’s technology has been proven in the on-line measurements of EAF phenomenon and has led to significant savings as energy efficiency improves. In addition, Luxmet’s technology can be used to study behavior of biochar in EAF to evaluate its potential applications in the EAF process. To start utilizing biochar in the process in the future, the first step is to take even better control with the current stage of operations with the ArcSpec solution.
Scrap based EAF is the most efficient technology available for steel production and the most environmentally friendly. Luxmet’s solution ArcSpec is a system that can measure and control EAF and it has been proven to significantly improve EAF’s energy and process efficiency. In the future, carbon free steelmaking will be possible when switching to hydrogen based DRI/EAF steel production, in which case renewable energy must be available at an affordable price. ArcSpec can reduce EAF’s electricity consumption by 3-8% and this will also be of great importance globally as the electricity consumption increases.
In the future, electricity consumption will increase significantly, therefore energy efficiency will be an important theme in the future, as well as producing electricity in an environmentally friendly way. Take the first step in saving electricity in your EAF process by contacting us. We will be happy to tell you more about how to make the EAF process more efficient and environmentally friendly. Also, don’t forget to follow us on Linkedin.
As we are active in development, please share your thoughts on these articles with us and your colleagues. We are always ready to discuss our unique technology to new needs of future processing of EAF furnaces.
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References:
Ellis, B. & Bao, W., 2021. Pathways to decarbonization episode two: steelmaking technology [online]. Available at: https://www.bhp.com/media-and-insights/prospects/2020/11/pathways-to-decarbonisation-episode-two-steelmaking-technology/ [Accessed 26 January 2021]
Hoffman, C., Van Hoey, M. & Zeumer, B., 2020. Decarbonization challenge for steel [online]. Available at: https://www.mckinsey.com/~/media/McKinsey/Industries/Metals%20and%20Mining/Our%20Insights/Decarbonization%20challenge%20for%20steel/Decarbonization-challenge-for-steel.pdf [Accessed: 25 January 2021]
IEA 2020. Iron and Steel Technology Roadmap. France: Paris. Available at: https://www.iea.org/reports/iron-and-steel-technology-roadmap [Accessed: 26 January 2021]
