The steel industry today is one of the biggest producers of greenhouse gases accounting for around 7% of the global total. This has started a race to find ways to reduce emissions while meeting the global steel demand that is expected to rise 11% to 2 billion tons in 2030 from 1.8 billion in 2020, according to Bronk & Company, a German consultancy.

Steelmakers are focusing on blast furnace - basic oxygen furnace (BF-BOF) process that accounts for 75% of steel production worldwide, according to the International Energy Agency (IEA).

“Over the last years, we have seen a significant increase in the interest in alternative technologies to blast furnaces allowing lower GHG emissions,” said Enrico Malfa, Director of Research and Development at Tenova.

“Tenova has developed with Danieli a direct reduction process, called ENERGIRON^®, that uses natural gas as a reducing agent of iron ore allowing to drastically reduce the CO2 Scope1 emissions compared to blast furnaces. The technology has an added benefit: it is hydrogen-ready. The natural gas can be partially or totally replaced with green hydrogen, giving a further contribution to reach the carbon-neutral goal of the steel sector in 2050”, Malfa said.

DECARBONIZING THE PRODUCTION CHAIN

The carbon neutral challenge however interests not only cutting emissions in liquid steel production but the entire production process. Therefore, the next step includes the substitution of fossil-fuels in reheating and heat treatment furnaces that contribute directly to Scope 1 CO2 emissions.

“Emissions from reheating and heat treatment furnaces account for about 10% to 15% of the direct emissions of steel production through the iron-ore route,” Malfa said, “and reach 70% for the scrap-based EAF route”.

The efforts over the past two decades have been focused on reducing operating costs and local environmental impact through innovative highly efficient technologies for combustion systems. The more efficient a furnace becomes, the less fossil fuel it burns and the less CO2 it produces. Tenova’s flameless recuperative and regenerative burner technologies, for example, improve furnace efficiency while also cutting nitrogen oxides to well below international limits.

Malfa explained that Tenova decided to take a step further. In 2020 an R&D project started with the focus on the decarbonization of re-heating and heat treatment furnaces following two directions: induction systems, and green hydrogen combustion. “We have proven that thanks to our flameless technology it is possible to extend the operation of our combustion system portfolio mixing hydrogen up to 100% with natural gas,” he said. “This opens the possibility to the new concept of electrified hybrid furnace, that thanks to the direct and indirect (by means of green hydrogen) use of renewable energy can drastically reduce CO2 emissions while maintaining a very low NOx emissions level”.

Tenova has applied this technology to develop its hydrogen-ready combustion technology: flameless recuperative burner for reheating furnaces (TSX) and Batch Annealing Furnace (THSQX), self-recuperative flameless burner for heat treatment furnaces (TRKSX). And it is working to extend it to the rest of the combustion systems portfolio.

In addition, the integration with Smart Burner Monitoring System (SBMS) - a state-of-the-art digital IIoT system – allows the regulation of the amount of hydrogen in the fuel mixture to adapt the combustion system to hydrogen availability and to monitor and optimize performance, operation, and maintenance of the burners thanks to embedded sensors connected to the Tenova Digital infrastructure”, Malfa stated.

Thanks to hydrogen-ready combustion technologies, companies are turning to hydrogen-ready plants. For example, TenarisDalmine in Italy is installing a self-recuperative flameless burner that will operate with a high percentage of hydrogen. To allow long-term testing, the hydrogen will be produced at the site of the furnace by an electrolyzer installed in partnership with Snam, a major gas distributor in Europe. This will allow Tenaris to test the use of hydrogen from production to combustion in the furnace and find guidelines for maximizing the benefits of this clean energy source to tackle the big challenge of producing green steel at a competitive cost.

RISING COMPETITION

Hydrogen-ready technologies can help steelmakers in the energy transition process. gradually incorporating more and more hydrogen into the production process to cut greenhouse emissions. During the energy transition, companies can’t afford to spend billions of dollars on new technologies without having the flexibility to adapt to future changes in legislation and to incorporate more hydrogen – and green hydrogen – as it will become available in sufficient quantity and at sustainable costs, Malfa said.

The infrastructure, for example, is today daunting. The production of low-emission hydrogen could surpass 20 million tons per year in 2030, up from 1 million in 2022, if all the proposed projects come online, according to the IEA. However, infrastructure must be built to generate low CO2 electrical energy, to produce, ship, and distribute the hydrogen, or to build on-site electrolyzers with high storage capacity.

Also, the competition for the available hydrogen between the different sectors can result in a bottleneck both in terms of availability and price. A Direct Reduction Plant with 2.5 million tons per year of capacity requires a 1 GW electrolyzer, Malfa added.

In fact, the availability of green hydrogen remains a challenge for the steel industry. “To produce green hydrogen, we must have sufficient quantities of renewable electricity available at competitive prices,” Malfa said. “This is a cross-industry problem that must be addressed step by step along the value chain, from production to end users. We have to find the best compromise in terms of efficiency, availability of low-emission energy sources, and steel production cost”.

In this scenario, flexible technologies are the key to enabling the steel production process to effectively respond, during the energy transition, to the expected gradual increase in hydrogen availability, says Malfa.