Steel is a huge part of our lives. It is an important component in our infrastructure, our vehicles, and in our appliances and equipment. However, the production of steel is extremely costly for the environment, and as the 21st century progresses, Sweden has found a new solution to cutting down the carbon emissions in the steel industry.
The Swedish corporation Svenskt Stål AB (SSAB, Swedish Steel Enterprise, LLC) is taking the lead in pioneering a new generation of steelmaking technology, but it isn’t what you think. The technology was meant to cut down the immense carbon footprint that the steel industry was making. SSAB has also partnered with the Swedish manufacturer Volvo to try and get the first vehicles made from this steel on the road by 2026.
The Current Steel Industry’s Impact On Climate Change
During the Industrial Revolution, factories started using coal, a type of fossil fuel, as their main source of fuel. This triggered warming in the Earth’s atmosphere as the combustion of coal creates a byproduct known as carbon dioxide, a gas that traps heat in the Earth’s atmosphere. As time progressed, this change became known as global warming. 100 years later, oil was discovered in the Middle East, creating even more carbon dioxide emissions as a result of oil being used to fuel vehicles and heat homes. Global warming got exponentially worse during the later half of the 20th century and the 21st century, as many big industries were pumping out millions of tons of carbon into the atmosphere. The steel industry was the worst of them though, pumping more than 3 billion tons of carbon yearly, as of 2022. This accounts for around 7% of global greenhouse gas emissions and 11% of carbon dioxide emissions. Even worse, the steel industry is also very important to the world, as it is used in framework and infrastructure, vehicle manufacturing, and heavy equipment. With the population growing, the demand for steel increases, and so the carbon emissions keep increasing.
How HYBRIT Decarbonises the Steel Industry
Regular steel is an alloy of steel and carbon, but the steelmaking process isn’t as simple as mixing carbon (usually coke or coal) and iron. First, the ore is heated to very high temperatures around 1426 degrees Celsius. Then the slag (waste product that forms as a result of heating a metal) is removed and the final product is a material called pig iron. Then, the oxygen is removed from the pig iron, creating the iron product that is ready for steelmaking. Finally the iron is refined and casted. After this processing of the iron product, steel is finally created. 75% of the world’s steel is made in huge blast furnaces with the indirect reduction process, which is terrible for the environment, as indirect reduction requires a lot of carbon for fuel.
The company aims to reduce the carbon footprint of the steel industry by developing a method that uses hydrogen to remove the oxygen during the reducing process, instead of mixing carbon with the iron. Compared to the traditional steelmaking process, the method reduces the iron to form gas-based direct-reduced iron (sponge iron) instead of indirectly reducing it. The technology also uses renewable energy sources, such as hydropower and windpower to power all parts of the steelmaking process and obtain the hydrogen needed for direct reduction.
SSAB’s green steelmaking technology, Hydrogen Breakthrough Ironmaking Technology or HYBRIT, involves the iron ore is first turned into pellets, then reduced, and finally deoxygenated. The iron ore is turned into pellets using the conventional process, just with renewable energy sources instead of traditional fossil fuel resources, such as coal, oil and natural gas. After the iron is pelletised, it gets directly reduced using green hydrogen and the reduced iron, now called sponge iron, is made into steel slabs for delivery.
Hydrogen that is used for reducing the sponge iron is produced by a process called electrolysis, in which hydrogen is siphoned off from water using electricity. The processing plants do this by using electricity from renewable energy to break the bonds between the hydrogen and oxygen molecules. Electrolyzers (machines that do electrolysis of water) don’t add to humankind’s water usage, making electrolysis a reliable, carbon-neutral way of getting hydrogen.
The reduction of the ore takes place around 800-1200 degrees Celsius, much cooler than conventional steelmaking. Instead of producing carbon dioxide, it produces water vapor. This is because there is oxygen in the ore, and it combusts with the hydrogen to form water. The excess water generated from the reduction process is then reused to get more hydrogen for reduction via electrolysis. The sponge iron is then processed, refined to remove impurities and finally made into slabs of direct-reduced steel, again using renewable energy to power all of the steps in the manufacturing process.
HYBRIT Steel: Better for the Environment, Superior To Conventional Steel?
Research conducted on HYBRIT steel reveals that the steel had superior properties when compared to conventional steel. The properties included that it is easier to handle, easier to transport and store, stronger than conventional steel, and the manufacturing quality of the steel is better, as well as superior mechanical and aging properties. But HYBRIT steel hasn’t really been used in real-world projects yet, so nothing can really be said about these claims. However, what we can say is that SSAB is taking a revolutionary step in decarbonising the steel industry. Other steel corporations are rapidly following suit, including Chinese steel giant Baowu and Indian steel giant Tata Steel. With these big innovations, reducing the steel industry’s gargantuan carbon footprint might actually be possible in the near future.
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