A cooperation between Salzgitter AG, the Fraunhofer Institute for Ceramic Technologies and Systems IKTS and the industrial furnace manufacturer TS ELINO GmbH aims to reduce the CO2 emissions of an existing steel mill by up to 97 per cent. The conversion to an environmentally friendly production method is to be achieved with the help of hydrogen.
The hydrogen, produced by electrolysis using green electricity, is used for the direct reduction of iron ore. The previous reducing agent, coke, will be completely replaced. This changeover would therefore make a significant contribution to climate protection.
Steel production in transition
Steel is a versatile and indispensable material, but traditional steel production has a considerable impact on the environment. In Germany, steel production emits around 55 million tonnes of CO2 every year. This accounts for around 28 per cent of total CO2 emissions from German industry. The use of coke in the production of pig iron in blast furnaces is the main cause.
The Fraunhofer Institute IKTS in collaboration with Salzgitter AG, is focussing on hydrogen-based direct reduction. In this process, iron ore reacts with hydrogen at high temperature in a reactor. The hydrogen as a reducing agent removes the iron oxide from the iron ore, leaving iron behind.
High-temperature electrolysis as the key to CO2 reduction
Green hydrogen is produced via high-temperature electrolysis using solid oxide electrolysis cells (SOEC). This method is particularly advantageous in steel production, as the waste heat from the high-temperature processes can be used. This increases the electrical efficiency. Fraunhofer IKTS uses in-house developments as electrolysis cells and stacks, which have already been successfully tested in the "MACOR" and "BeWiSe" projects.
"We use electricity from renewable energy sources, so the production of hydrogen is completely CO2-free. In this way, crude steel production using green hydrogen saves up to 97 per cent of climate-damaging carbon dioxide," explains Dr Matthias Jahn, Head of the Energy and Process Engineering Department at Fraunhofer IKTS.
