Direct reduction plantDecarbonization at thyssenkrupp Steel

How does a direct reduction plant work?

Blast furnaces have long been a symbol of the steel industry, where iron ore is reduced and processed into hot metal. Traditionally, iron ore is processed using coke and hot air. However, due to the use of coal, this process generates large amounts of CO₂.

The direct reduction plant currently being built in Duisburg-Walsum is ushering in a new, greener era of steel production through the use of hydrogen. In the future, the new process will make it possible to avoid large amounts of CO₂ emissions. But how exactly does it work?

How does a direct reduction plant work?

Blast furnaces have long been a symbol of the steel industry, where iron ore is reduced and processed into hot metal. Traditionally, iron ore is processed using coke and hot air. However, due to the use of coal, this process generates large amounts of CO₂.

The direct reduction plant currently being built in Duisburg-Walsum is ushering in a new, greener era of steel production through the use of hydrogen. In the future, the new process will make it possible to avoid large amounts of CO₂ emissions. But how exactly does it work?

Visualization of the direct reduction plant at thyssenkrupp Steel.

The DR plant is supplied with iron ore in the form of iron ore pellets or lump ore, which is initially stored temporarily. The iron ore is then transported into the 40-meter-high DR tower. Next to the tower is the reformer, where the required reducing gas is produced – a mixture of hydrogen, natural gas and recycled process gases.

The reducing gas is fed into the gas stream of the DR tower to remove oxygen from the iron ore. In conventional blast furnaces, this process is much more carbon-intensive: Coke and hot air produce carbon monoxide, which removes the oxygen from the iron ore. The high temperatures then produce liquid hot metal.

In contrast, hydrogen is used in the DR tower to remove the oxygen. This also produces iron. However, very high temperatures are required in the DR tower. Temperatures of between 700 and 900 degrees Celsius are needed to turn the iron oxide into solid sponge iron. Gases are also produced during this process. To make production more sustainable, these gases are fed back into the gas cycle. The recycled process gas is returned to the reformer, where it can be reused together with hydrogen and natural gas.

The resulting product is solid sponge iron, also known as direct reduced iron (DRI). The sponge iron can then be transported to the melters – electrically powered furnaces that melt the material. A continuous melting process takes place there, with electricity from renewable sources planned for the future. This also helps reduce CO₂ emissions.

As in conventional iron production, there are separate tap holes for the hot metal and slag after melting. The liquid slag is transported to the slag granulation unit. Granulated slag is used, for example, in the cement industry. The hot metal, meanwhile, is tapped into torpedo ladles and transported to the steel mill. The innovative concept of the DR plant can therefore be integrated into the existing steel production process, enabling high-quality yet more sustainable steel production.

Teamwork for a more sustainable industry

However, a transformation of this scale cannot happen overnight. Coordinating the construction of plants and buildings as well as planning the energy and material supply requires experts from a wide range of disciplines. At thyssenkrupp Steel Europe, teams from metallurgy and mechanical engineering work closely with experts from chemistry, process engineering and electrical engineering.

As the DR plant is the first of its size designed to operate with hydrogen, extensive expertise is required. And to integrate the new plant seamlessly into steel production, precision and teamwork are particularly important.

Hydrogen as a key to climate neutrality

thyssenkrupp Steel’s future DR plant is one of the world’s largest industrial decarbonization projects. It is helping to drive the green transformation of an entire industry. In the future, the plant is intended to operate with green hydrogen – hydrogen produced using renewable energy.

A DR plant requires large quantities of hydrogen, making the Rhine-Ruhr region an ideal location. The site is located along Germany’s hydrogen core network, making it possible to supply green hydrogen via pipeline – and enabling more sustainable steel production.

thyssenkrupp Steel is therefore not only set to become one of Germany’s largest hydrogen consumers, but also an important part of the hydrogen economy and, ultimately, industrial decarbonization. In the long term, we also aim to decarbonize the subsequent crude steel production process. A more sustainable industry for the future – that is what drives us.