DRI-EAF implementation at Saarstahl / Dillinger steelworks (POWER4STEEL)

Saarstahl and Dillinger are transitioning from the conventional BF/BOF route to the DRI/EAF route. Saarstahl (located in Völklingen) produces long products while Dillinger (located in Dillingen) produces heavy plates. Two EAFs are scheduled for commissioning in the second quarters of 2028 and 2029. The DRI plant (Dillingen) will be commissioned in the third quarter of 2029, after this a blast furnace will be closed in 2030. This transformation will lead to meet fit-for-55 targets by 2030.

TECHNICAL DESCRIPTION:

The core units of the Power4Steel project are the DRI plant in Dillingen and one EAF each in Völklingen and Dillingen. The DRI plant in Dillingen uses the Midrex Flex technology. The construction of the DRI plant and the EAF will be carried out by Primetals Technologies and the DSD Steel Group. The DRI plant has an annual capacity of 2 million tonnes of DRI. The EAF in Dillingen is designed for a weight of 195 t per heat. The EAF for Saarstahl will be constructed by SMS Group and is designed for a weight of 190 t per heat. The entire construction project will require 300,000 m3 of concrete and more than 100,000 tonnes of steel.

In Dillingen, the core units will be built besides the existing steel plant and near the existing rolling mill. The core units are supplemented by a hot link from the DRI plant to the EAF to transfer hot DRI directly to the EAF with significant savings in terms of energy consumption. Cold DRI bins are also built to supply the EAF in Völklingen with passivated cold DRI. Due to an increasing demand for scrap, a scrap yard will also be built near the EAF in Dillingen. Additionally, a new electric power supply and a hall for slag treatment is necessary. The amount of steel mill slag will increase compared to the conventional route while the amount of blast furnace slag will be reduced if one of the furnaces closes.

In Völklingen, the EAF building with a dedusting plant will be built besides the existing steel plant. As in the Dillingen plant, a scrap yard to manage the increased scrap demand, cold DRI bins to store cold DRI and a slag treatment facility will be built. Additionally, an expansion of the secondary metallurgy will be necessary in Völklingen.

The main environmental purpose of the transition from BF/BOF to DRI/EAF is the reduction of CO2 emissions. ROGESA currently operates two blast furnaces in Dillingen, which melt and reduce iron ore using coke to produce pig iron. This is then supplied to the BOFs in Völklingen and Dillingen. In Step 1, CO2 emissions are reduced by the DRI plant using natural gas `while DRI and scrap are melted into crude steel using the EAF and electricity. Further reductions in carbon emissions can be achieved in step 2 by substituting natural gas with hydrogen and using green electricity in the EAF. The new DRI/EAF route will aim to a 50:50 ratio of DRI and scrap, primarily due to CAPEX optimisation.

DEGREE OF MATURITY
Steel production with a DRI plant using natural gas combined with an EAF is already commercially available with very high degree of maturity.
However, the use of 100 % H2 in the MIDREX process will need to be demonstrated full scale and is currently on the demonstration level to reach TRL 7/8.
Increasing the hydrogen content is not only a question of technological maturity, but also of hydrogen availability in the future. After commissioning of the DRI plant in 2029, the hydrogen content is to be gradually increased over the years, if sufficient hydrogen is available.


CROSS-MEDIA EFFECTS:
In the current BF/BOF route, slags produced can be mainly sold as a building material after cooling and preparation. In the future DRI/EAF route, this is not straightforward, and it is much more challenging to fulfil the environmental demands for using electric furnace slag as a building material. This issue is currently under investigation as part of the EU funded project InSGeP (Investigation of Slags from Next Generation Steel Making Processes), in which Saarstahl is involved. This project is exploring potential paths for the valorisation of slags produced in the DRI-EAF value chain.

Basic information about the technique

Participant Companies