Steel experts have been taking a virtual look inside a shaft furnace, as part of a new project to test how well hydrogen would work as a reductant for steelmaking. If switching to hydrogen from fossil fuels proves feasible, it would slash the carbon emissions from steelmaking.
The team used laboratory simulations to get an accurate picture of how hydrogen and other materials behave in the extreme conditions of a furnace, as a first step towards piloting a new type of hydrogen-fuelled process.
This was a collaborative project, with the Steel and Metals Institute, based at Swansea University, and the Materials Processing Institute, based in Middlesbrough, working directly with global metals and mining companies. The project was funded by the BEIS Industrial Fuel Switching Programme.
A low-carbon green economy needs steel, for example for products such as wind turbines, trains or electric cars. Steel can also be recycled infinitely, with no loss of quality.
However, the process of manufacturing steel remains carbon-intensive, despite major improvements by the sector in recent years. 6% of global carbon emissions come from the ironmaking process alone. A single blast furnace produces 5 million tonnes of carbon each year.
This is why the team’s focus on hydrogen as a fuel for furnaces has such enormous potential to cut emissions. They are looking specifically at a process known as reduction, which means removing oxygen from a material.
At present, iron is reduced in the furnace using carbon monoxide from coke, a coal-based fuel, which attracts the oxygen from the iron ore. The result is that the iron ore becomes pure iron, ready for steelmaking. The flip side, however, is that the carbon monoxide, with the extra oxygen atom added, becomes carbon dioxide – CO2 – and adds to the emissions that are worsening the climate crisis.
If hydrogen could be used to reduce the iron, instead of carbon monoxide, it would drastically reduce carbon emissions from steelmaking.
The team examined how materials behaved in the hydrogen reduction process. To do this, they used unique technology based at Swansea University’s Steel and Metals Institute (SAMI). Known as the reducibility rig, it simulates what happens to materials at very high temperatures in gas-laden environments.
Dr Mike Dowd, Facilities Manager at the Steel and Metals Institute at Swansea University, said:
“Switching to hydrogen as a reducing agent for steelmaking would slash carbon emissions. Our work tested how this technology could work, before we start the next phase of this project.
The reducibility rig in Swansea allows us to take a virtual look at the hydrogen reduction process could work on an industrial scale. It means we get a full picture of how materials behave in extreme conditions. We also compare hydrogen with carbon-heavy fuel sources.
With investment, the new hydrogen furnace technology could replace the need for blast furnaces altogether.
The tools we are using and our links with industry mean that this project could scale up these technologies for commercial use quite quickly. This is crucial as we all know that time is of the essence in the drive to cut carbon emissions.”