Process design to reduce CO₂ emissions in steel production

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by Oxana Schmidt

The NEFI-project „OxySteel“, directed by Dipl.-Ing. Johannes Dock, is concerned with increasing energy efficiency in electric steel production. The process layout is used to explain how CO₂ emissions can be reduced by using new technologies.
It deals with the question to what extent new technologies and demand side management measures can be used to increase energy efficiency and the share of renewable energy sources in electric steel production.

The use of oxyfuel combustion and Carbon Capture and Utilization (CCU) in the electric steel plant is expected to reduce fuel consumption and CO₂ emissions. The research project focuses on the optimal integration of these technologies into the overall energy system of the steelworks. In the course of the demonstration project, three so-called ladle furnaces, which are used to heat the steelworks ladles, will be equipped with oxyfuel burners. Both the waste heat and part of the CO₂ produced will be used within the plant.

The process layout shown in the figure provides for natural gas/oxygen combustion with subsequent condensation of the flue gas. This leads to an increase of the CO₂ concentration in the flue gas and enables the recovery of the heat present in the flue gas. The CO₂-rich flue gas is then compressed, stored and used to neutralise the waste water and in the cooling towers. Recovered heat is used to preheat feed water in the process steam boiler. The demonstration plant is currently in the engineering phase. The project consortium comprises Breitenfeld Edelstahl AG, Messer Austria GmbH and University of Leoben.