CO2 recycling could reduce iron and steel sector emissions
The iron and steel industry remains one of the biggest emitters of carbon dioxide (CO2), accounting for up to 9 % of global emissions. Addressing this will be critical if Europe is to meet its greenhouse gas reduction commitments. “Over 70 % of iron and steel production uses blast furnaces,” says DISIPO project coordinator Manuel Bailera from the University of Zaragoza in Spain. “This involves reducing iron ores with coke in a blast furnace at temperatures beyond 1 000 °C. This produces huge amounts of CO2 in the process.” Many of these facilities are relatively new, and could still be operational in 30 to 40 years. While transitioning towards greener production methods is essential, it is also crucial to find ways of making blast furnaces less polluting.
Closing the carbon loop and reducing coal consumption
This was the key aim of the DISIPO project, which was supported by the Marie Skłodowska-Curie Actions programme. “My objective was to see if we could decarbonise blast furnaces by recycling their CO2 emissions into e-fuels,” explains Bailera. “These could be then used by industry, closing the carbon loop and reducing coal consumption.” E-fuels, or electrofuels, are manufactured using captured CO2, together with hydrogen obtained from sustainable electricity sources such as wind, solar and nuclear power. To assess the feasibility of this, Bailera developed new simulation models for assessing how CO2 recycling could be introduced into blast furnace plants. As part of the project, Bailera spent time at Waseda University in Japan, where he worked on validating a new operating model. Collaboration with steel plants in both Japan and Austria enabled Bailera to adapt operating strategies and economic analyses to real industrial scenarios and data. “In Austria, I also evaluated the potential installation of photovoltaic panels on the roof of a steelmaking plant, in order to provide renewable electricity,” he notes. “And back in Spain, I was able to compare these new CO2 recycling concepts with conventional ironmaking processes, in order to quantify the potential reduction in CO2 emissions.”
Advancing knowledge of power-to-gas integration
This research has helped to advance knowledge of power-to-gas integration in iron and steelmaking, i.e. the use of electric power to produce a gaseous fuel – as well as the potential for recycling CO2. These topics have not been studied in depth until now. In the Nakagaki Laboratory at Waseda University, Bailera’s models are currently being used for further internal research, as well as collaborations with industry. Some Japanese partners are planning to build a blast furnace pilot plant, to test the concept. “The simulation models developed in this project have also been used by the University of Zaragoza for ongoing projects on iron and steel,” Bailera adds.
Progressively decarbonised through carbon recycling
In order to continue this research, Bailera would also like to build a pilot blast furnace, capable of recycling CO2. “This is important, as all the different subsystems used in the recycling concept will need to be demonstrated under industrial conditions,” he says. “For example, there might be contaminants in the CO2 that are then recycled into e-fuels. This is currently under research at the University of Zaragoza, as a continuation of the DISIPO project.” Ultimately, Bailera hopes that this work will help to decarbonise ironmaking, through enabling a transition period in which blast furnaces are progressively decarbonised through carbon recycling.
Keywords
DISIPO, steel, iron, CO2, emissions, recycling, decarbonisation, furnace
