The paths towards an economically and environmentally sustainable European steelmaking industry are winding, but technologies are already available to overcome the challenge.
The European steelmaking industry is moving towards natural gas-based (short-term) and hydrogen-based (long-term) iron reduction as substitute for carbon-based processes, as part of the ambitious decarburization goals of Europe’s economy by Carbon Direct Avoidance (CDA). However, this path represents an extreme challenge, especially in the current scenario, considering the difficult economic conditions, the shortage of raw materials and the geo-political tensions affecting gas availability. The crucial question is:
How is it possible to achieve these objectives while maintaining competitiveness in the world market?
European steelmaking: What routes?
The iron and steel industry is one of the largest CO2 emitters, responsible for 7% of total CO2 emissions in Europe and 7-9% of global anthropogenic CO2 emissions. In the current EU context – where CO2 intensity of electric power generation is about 290 g/kWh – electric steelmaking generates about 400-500 kg of CO2 per ton of liquid steel; whereas the integrated steelmaking route via Blast Furnace and Basic Oxygen Furnace (BF-BOF) produces at about 1600-1800 kg of CO2 per ton liquid steel, depending on the efficiency of the installation.
The emissions from the conventional BF-BOF route represent the greatest potential for CO2 reduction for the steel making industry considering that, as of 2019, 70.8% of the steel in the world came from the BF-BOF route mostly processing iron ore, while only about 28.9% was produced via the electric process – a share of approximately 90% in terms of CO2 emissions.
Apart from the CO2 emissions of iron and steel production, the processes of steel refining and further downstream processing are other factors in a holistic approach to CO2 mitigation or avoidance that cannot be neglected, as they are responsible for approximately 60-360 kg of CO2 per ton of steel – depending on specific process route.
Our approach: Hydrogen-ready technologies for the transformation process
Reliable tools to support each phase of this transformation process exist and represent the perfect solutions – with the highest flexibility and minimized negative economic impact.
The most important approaches to decarbonizing steel production are two:
- The direct conversion and complete replacement of the BF-BOF route with a gas-based Direct Reduction and Electric Arc Furnace (DRP-EAF) route. The reduction of CO2 emissions can be further enhanced by the partial or total use of hydrogen for DRI production. This solution is already widely adopted in the industry and Tenova produced the most productive DRI-fed EAF in the world and is now building a second one.
- Replacing the BF ironmaking installation only by gas-based Direct Reduction and Open Slag Bath Furnace (DRP-OSBF) for production of hot metal. This is called Tenova iBlue® process. Again, the usage of green hydrogen in the reduction process can minimize greenhouse gas emissions furtherly. This represents an attractive possibility to produce pig iron with the minimum carbon footprint and can be considered as a Low-Capex solution towards full decarburization of steelmaking. Although there are no existing plant at present running iBlue®, there are many ENERGIRON® plants in the world and Tenova produced hundreds of OSBFs in the world.
A qualitative assessment of the process routes
The choice between the two process routes has to be made according to the specific case, taking into account not only technological but also local and sourcing factors. Therefore, a detailed study is a prerequisite to support the decision-making process.
For both routes, the ENERGIRON® technology – jointly developed with Danieli – offers the greatest possible flexibility and the least need for change of plant configuration and equipment, while requiring the lowest operating costs. This solution is ideal as the basis of pig iron or steel production. Its flexibility with regards to iron ore pellet qualities and the reduction gas minimizes subsequent adjustments to the plant design.
The DRP-EAF route and the iBLUE® process have different CO2 emissions, which need to be evaluated in the already-mentioned detailed study.
Furthermore, the metallurgy of the steel grades produced via the two routes is different and it is a driver of the decision. These considerations need to include also the possibility to add different percentages of scrap (to oversimplify, the cleaner the steel to produce, the lower the allowable amount of scrap).
Additionally, the main difference between the two solutions lies in the use of scrap, the reduction gas mix and slag composition.
Thanks to iBLUE® and the DRP-EAF route, Tenova is the company that nowadays represents the most ready player in the industry to offer a differentiated and consolidated portfolio of technologies to make the green steel transition happen already today.