Steel industry gathers to discuss sustainability

INDUSTRY workers and researchers from across the steel sector gathered for the virtual bi-annual SUSTAIN conference in December 2021, which was titled Sustainability in Steel. SUSTAIN – Strategic University Steel Technology And Innovation Network – is a collaborative research hub working towards transforming the UK steel sector into a cleaner and smarter industry.

Emissions from steel production

Steel is typically produced one of two ways: the blast furnace-basic oxygen furnace (BF-BOF) method, or the electric arc furnace (EAF) method. For the former, iron oxide is converted to iron ore in the BF using a reducing agent which is typically coal. The molten iron is then fed into the BOF where the added oxygen lowers the carbon content to the level required to produce steel.

An EAF produces steel using an electric arc to produce the high temperatures needed. The feedstocks for an EAF can either be steel scrap or directly reduced iron (DRI). For DRI, the iron oxide is reduced while remaining in a solid state and without the need for melting as is done in the BF. The reducing agent is mainly natural gas, but coal can also be used.

According to the World Steel Association, around 70% of global steel production is via BF-BOF, and 30% is via EAF. The steel sector is currently responsible for around 7 – 9% of global emissions and 15% of UK industrial emissions. There are various potential solutions for decarbonising the industry, including using hydrogen, carbon capture and storage (CCS), and making better use of steel scrap.

Using hydrogen

A potential way to produce lower-emissions steel is to use hydrogen in the process. This can either be done by using hydrogen directly in the BF so that less coal is needed, or it can be used as the sole-reducing agent to make DRI.

Peter Warren, Development Metallurgist at British Steel, described using hydrogen in blast furnaces as an “overhyped subject”, pointing out that that hydrogen doesn’t generate any heat in the lower part of the furnace; it’s purely a reductant. “It’s an interim possible solution, but it’s not going to change the world in the way that we need to decarbonise”.

Mark Allan, Group Manager for Industrial Decarbonisation at the Materials Processing Institute (MPI) spoke of plans that are currently in development to establish a t/d H₂ DRI pilot facility and integrate it with the existing EAF at the MPI.

However, Sara Hornby, Owner of Global Strategic Solutions and Services, expressed concerns over the move to hydrogen use in steelmaking. She said that one issue will be construction rates of new DRI facilities.

We need to actually understand what happens if we throw billions of tonnes of extra water into the atmosphere, bearing in mind that [across] the entire planet, all the climate is driven by water being evaporated, moving around, condensing and then falling as rain. We need to model that.

Peter Holliman, Professor of Materials Science and Engineering at Swansea University, cautioned that even though using hydrogen as a fuel only emits water, water vapour in the atmosphere absorbs radiation from the Sun.

“We need to actually understand what happens if we throw billions of tonnes of extra water into the atmosphere, bearing in mind that [across] the entire planet, all the climate is driven by water being evaporated, moving around, condensing and then falling as rain. We need to model that.”

Capturing emissions

Enrico Andreoli, Associate Professor in Chemical Engineering from Swansea University, described the work he is doing on using electrolysis to generate useful chemicals from CO2 captured in the steel industry. He spoke of how CO2 electrolysis can be integrated into the steel-making process.

Using carbon capture on blast furnace gas creates a CO2 source for the solid oxide electrochemical cell (SOEC). The SOEC generates syngas which is fed back directly into the blast furnace. The CO then works as a reducing agent which means that less coke is necessary to reduce the iron ore. The SOEC also generates oxygen simultaneously which can be used directly in the oxygen blast furnace.

This system needs renewable electricity but also heat, requiring an operational temperature of 800–900^oC. Andreoli and colleagues are working on a process to remove the need for the extra heat by using an alkaline electrolyser which can be operated at room temperature and pressure, which is still at lab scale. Using an alkaline electrolyser doesn’t generate syngas as efficiently as using an SOEC, however an alkaline electrolyser can be used to generate a large group of chemicals such as HCOOH, MeOH, EtOH, C₂H₄.

“This then links steel production to the chemical industry,” said Andreoli. “We would have to think about integrating the two and find an approach on how all these products generated from this alkaline electrolyser could be then joined into the chemical industry, which needs to be defossilised as much as the steel industry.”

Peter Styring, Professor of Chemical Engineering and Chemistry at the University of Sheffield, spoke of a CCU project in development called FluRefin. This is a flue gas refining system which uses simulated flue gas and a pressure swing adsorber. The system is adaptable and can be used on any source of CO₂, including direct air capture, HVAC air conditioning, combined heat and power plants, or steel gases. Styring and colleagues are currently working on FluRefin Gen2 with the aim to test it on real sources to see if the system works at higher volumes. They are also investigating using the captured CO2 for fuel production, with a focus on DME, kerosene, and diesel to replace fossil fuels.

Is the EAF the best solution?

Zushu Li, Reader and EPSRC Fellow in Manufacturing at the Advanced Steel Research Centre, WMG of the University of Warwick, discussed the different technologies that can be used to help get steelmaking to net zero and said that scrap-based EAF is the most practical technology to be ready by 2035, although the others such as using CCUS and hydrogen were also likely.

Richard Warren, Head of Policy and External Affairs at British Steel, said that if you wanted to recycle all the scrap that is available, you’d need significantly more EAF capacity. There are lots of policy barriers to achieving this, as well as the electricity being more expensive in the UK than any other steel-producing nation.

Geoffrey Brooks, Professor of Engineering at Swinburne University of Technology, said that it is often highlighted that the EAF has much lower CO2_­ emissions compared to BOF, however it is not quite as simple as that. He pointed out that there is actually a lot that can be done to bring emissions down from the BOF and that there are also issues with EAF. For example, the EAF has lower productivity even though it can use more scrap, and it has heat losses of 30–40%. In addition, as rich iron ore becomes depleted, lower quality ore will have to be used for DRI-EAF which will push emissions up.

He suggested that it might be better to rethink the BOF, for example developing it to deal with a wider range of feed materials and increasing the amount of scrap that can be processed in the BOF. Heat loss is much lower than the EAF – at around 10% – and this would decrease further if more scrap could be used. He noted that there are challenges with using scrap, as impurities can make it difficult to use it to produce high-grade steel. However, he thought that overcoming this challenge would be simpler than trying to melt a large amount of DRI in the EAF.

Towards greener steel

Richard Warren said that recently the UK Government has shown serious commitment to supporting the steel sector towards decarbonisation. There have also been positive policy developments, such as the Climate Change Committee (CCC) recommendation that ore-based steel production needs to be decarbonised by 2035. More widely, the Glasgow Breakthroughs announced at COP26 include a commitment to establish net zero steel production in every region in the world by 2030.

He added that collectively, this and other initiatives give the industry reason to believe that it is heading towards green steel. However, he noted that the UK £250m Clean Steel Fund – which was announced two years ago – has yet to be confirmed.

We need to think about sustainability from the very beginning of our research. I think this should inform our research. It should not be a limit to creativity.

Cathy Bel, Manager Research and Forensic Metallurgy at Liberty Steel, highlighted that the whole supply chain needs to be decarbonised. “There’s a lot of pressure on the steel industry to decarbonise and there’s less pressure put on the steel supply chain to decarbonise […] At COP26, steel manufacturers were highlighted as entities that produce a lot of carbon [emissions], but what about the whole supply chain? What’s their responsibility to decarbonise the product?”

Li also commented on the 2030 target from the Glasgow Breakthroughs, saying that while it creates a lot of pressure on researchers and industry, it should also be seen as an opportunity.

Cinzia Giannetti, Associate Professor of Mechanical Engineering at Swansea University, said: “We need to think about sustainability from the very beginning of our research. I think this should inform our research. It should not be a limit to creativity. It should actually be an enabler to creativity to find solutions that are sustainable. Otherwise we might develop solutions that are not sustainable and then we cannot implement them because they won’t be beneficial to society.”

Speaking on industry and academia working together, Claire Davis, Tata Steel Professor of Thermo-mechanical Processing at the University of Warwick, said that there tends to be a focus on where there would be benefits for industry, which is challenging for academics as it might not initially be obvious in early research projects where a benefit might arise. “From an academic perspective, we need to do the things that may not be of benefit […] I like the fact that we do things that push the understanding before we actually have necessarily need of it […] It is our job to push that forward and then try and demonstrate where that benefit might be.”

Taking advantage of digitalisation

Iain Todd, Professor of Metallurgy at the University of Sheffield, said: “Materials has been a little bit late to the game coming to look at use of data-driven innovation and digitalisation, although we’ve been doing lots of things with data for a very long time. It’s always been difficult to know where to begin.”

He spoke about work that he’d led on behalf of the Royce Institute, published in 2021 which explored the idea of Materials 4.0. The key recommendation is to establish a national steering group for digital materials and manufacturing.

Arnold Beckman, Professor of Computer Science at Swansea University, highlighted the benefits of moving to Industry 5.0, which is similar to Industry 4.0, but tries to put humanity in the centre by achieving societal goals and prioritising the wellbeing of industry workers, as well as respecting the planet.

Jan Godsell, Professor of Operations and Supply Chain Strategy at Loughborough University, spoke of a systematic literature review that she worked on in 2020 while working at WMG to look at circular economy practices within supply chains. They used the review to identify two critical drivers for the circular economy: adoption of industrial digital technologies and integration with supply chain partners. She said that the majority of companies surveyed have a low rating for both of those drivers, but suggested ways to improve the adoption of industrial digital technology such as developing business cases for digital technologies, and using “3D concurrent engineering” which means designing the product, process, and supply chain concurrently.

We can talk about getting to the future – what are we going to do with hydrogen in the future – but it’s really important to have optimisation now

Steven Winkley, UK Metals Sector Sales Manager at ABB, spoke of ABB’s work in developing solutions for the steel industry to help it reach net zero, such as optimising existing processes. He gave the example of a smart melt shop, which can provide real-time tracking of positions of equipment as well as tracking processes. There is an increased use of automation as well as thermal prediction models to decrease heat loss. “We’ve tied the whole thing together to create a smart factory. That means that you take people away from dangerous situations as well.”

He said this has been implemented at a facility in India and led to increased productivity, energy efficiency, and safety. “This is a transition technology. We can talk about getting to the future – what are we going to do with hydrogen in the future – but it’s really important to have optimisation now.”

Dean Stroud, Senior Lecturer in the School of Social Sciences at Cardiff University, spoke of a just transition in the steel sector, saying it is important to upskill workers. He gave a list of skills needs from a European Steel Skills Alliance report. These include digital skills, data analysis, metallurgical skills, advanced engineering, and IT skills. He talked about another report on the barriers to Industry 4.0, some of which are skills-related such as lack of knowledge about technology and lack of in-house talent. Concern about cybersecurity is also a barrier and something which requires the development of appropriate skills.

He cited a report from Cardiff University which found that while 92% of steelworkers see the green transition as necessary, only 55% believe they currently have the right skills for the transition. “The steel industry requires a greater focus on transferrable and digital skills and more training resources need to be devoted to these areas”.