Foto © Breitenfeld Edelstahl AG/Stefan Nadrag
In the OxySteel project research is being conducted into energy efficiency and CO₂ reduction measures in steel production. As the metallurgical industry relies heavily on fossil fuels, energy efficiency and CO₂ reduction measures in this sector are crucial to meet the CO₂ reduction targets. The development and implementation of a new process design using oxy-fuel combustion and Carbon Capture and Utilization (CCU) is expected to save fuel and CO₂ emissions. The research project focuses on the optimal integration of the technologies into the overall energy system. The process design developed will be tested in an industrial environment at the demonstration site in the Breitenfeld steelworks.
„For me, the steel industry is so exciting because you achieve great leverage. For example, we expect the implementation of OxySteel alone to result in annual energy savings of 12 GWh. This corresponds to about 10% of the annual natural gas consumption of the city of Leoben. With a corresponding technology rollout, the savings are many times higher.“
The Breitenfeld Edelstahl AG produces around 130.000 tons of steel per year at its site in the Mürztal. For this purpose, scrap is melted in an electric arc furnace and processed into high-quality steel products. Besides the electric arc furnace, the main energy consumers are the ladle furnaces, which are used to heat the steelworks ladles. These are currently operated with conventional natural gas burners. The aim is to achieve an energy saving of 6% per year and to save 2.700 t CO₂ per year through more efficient combustion and internal use of CO₂. In the course of the demonstration project, three ladle fires will be equipped with oxyfuel burners. The process design also provides for subsequent condensation of the flue gas. This leads to an increase in the CO₂ concentration in the flue gas and enables the heat present in the flue gas to be recovered. The CO₂-rich flue gas is then compressed, stored and used for environmentally friendly waste water neutralisation and in the cooling towers. Waste water neutralisation at the production site is already carried out with CO₂, but the CO₂ must be purchased at present. The recovered heat is used to preheat feed water in the process steam boiler. The demonstration plant is currently in the engineering phase.
Another target of OxySteel, using a comprehensive analysis and modelling of the energy system, is to identify flexibility options and Demand Side Management (DSM) potentials to support the integration of variable renewable energy sources and provide possible grid services. The energy system model is also used to develop and evaluate future scenarios.
OxySteel contributes to the NEFI innovation fields of Energy Efficiency & New Processes and Renewables, Storage & DSM.
In January 2022, the first of three new Oxyfuel ladle furnaces went into operation at the Breitenfeld Edelstahl AG steelworks. The so-called ladle furnaces are used to preheat the steelworks ladles, the transport and treatment vessels for liquid steel, and are responsible for a large part of the natural gas consumption and CO₂ emissions at the EAF steelworks.