Solution 3 - Direct reduction is optimization target

The steel industry is responsible for 30% of industrial emissions in Germany, making it the largest contributor to industrial greenhouse gas emissions. Nationwide, this amounts to 6% of total emissions!
 

An opportunity: The steel industry can make a significant contribution to climate neutrality. If sufficient green electricity is available, steel could become CO₂-neutral through direct reduction with hydrogen. In the transition period, considerable CO₂-savings are already being achieved by using natural gas instead of hydrogen. The best solution at present is therefore the DRI route.

According to the sample calculation in ISO 14404.3, 1,455 tons of CO₂ are produced during crude steel production. By replacing coal and gas with green hydrogen, 90% can be saved.

In the new DRI (direct reduced iron) route, green hydrogen is used to reduce iron ore pellets in the reactor. The sponge iron obtained is melted together with recycled scrap in the electric arc furnace to produce crude steel. The cast slabs are then rolled out in the hot rolling mill and, if necessary, further refined and the surfaces coated. This process produces around 0.15 tons of CO₂ per ton of crude steel. That is less than a tenth of the emissions from the blast furnace.

How far has this new path been developed in Europe?

Replacing the blast furnaces and basic oxygen furnaces (BF-BOFs) of a traditional integrated steel plant with production based on direct reduced iron and electric arc furnaces (DRI-EAFs) is a mature technology option. There is also a variant in which the direct reduced iron (sponge iron) is melted in a smelter and processed into crude steel in the traditional oxygen steel plant.

DRI production plants consume high quality iron ore pellets and are fueled by natural gas (NG). In time, however, they will likely also use green hydrogen (H₂). This technological improvement could reduce emissions by 33% to 55% compared to BF-BOF production, taking into account Scope 1, Scope 2 and upstream Scope 3 emissions. Over 100 million tons of natural gas-based DRI-EAF production capacity is already in operation worldwide. This gives reason to be confident that this technology will have a significant impact on the future.

DRI is usually produced in special plants known as DRI plants or HBI (Hot Briquetted Iron) plants. In these plants, iron ore, often in the form of pellets or powder, is heated and chemically reduced in a reducing gas stream, usually consisting of hydrogen (H₂) and carbon monoxide (CO). This extracts the iron from the ore and produces it in the form of DRI or HBI products.

The use of DRI as a raw material for steel production offers great advantages:

1. Lower CO₂-emissions: As no coking coal is required for DRI production, there are fewer CO₂-emissions than with traditional blast furnace production.
2. Flexibility: DRI can be used flexibly in steel production, whether in electric arc furnaces or as an additive in conventional blast furnaces to reduce the CO₂-footprint.
3. High degree of purity: DRI has a high degree of purity and contains only a few impurities, which is an advantage in steel production.
4. Verbesserte Qualität: Die Verwendung von DRI kann die Qualität des Endprodukts in Bezug auf die Festigkeit und andere mechanische Eigenschaften verbessern.
5. Reducing resource consumption: As DRI is often made from iron ore pellets, it can help to reduce the need for iron ore and thus conserve natural resources.