The most prominent sustainable technologies in the iron and steel industry
The most prominent sustainable technologies in the iron and steel industry
The iron and steel industry represents an actual aspect and a fundamental pillar in our lives today; Because of their direct impact on construction development, including: homes, hospitals, roads and other infrastructure, the iron and steel industry contributes to building the social foundation and economic growth of all countries. Steel is one of the most recycled materials, but the high temperatures that are vital to the production process still require large amounts of fuel to generate the energy needs of this industrial process. Hence, the Iron and Steel industry remains among the largest energy consuming industries; Thus, it accounts for a large share of “carbon dioxide” emissions, as this industry emits between “6% to 7%” of greenhouse gas emissions globally.
With increasing global concerns about climate change, many companies, along with investors and governments, have realized the necessity and urgent need to transform this industry into sustainability, by converting the industry to technologies that remove “carbon” and reduce its emissions.
Background on the iron and steel industry
Steel occupies third place in terms of abundance of bulk man-made materials after cement and wood, and represents an integral material used in most construction and industrial purposes, as we find it as a main input in construction and infrastructure work, and the manufacture of machinery, means of transportation, and other goods.
In 2020, the largest use of steel (52%) was in construction and infrastructure, the machinery industry (15%), and the automotive industry (12%).
The raw materials for steel production – ore iron , coal and limestone – are generally cheap and abundant in the primary production process. These components are transformed into molten steel through a series of chemical reactions that occur under very high temperatures. The heat required for the production process is generated through coke, or through other energy sources, in order to feed the giant production furnaces. Materials such as: “chromium or titanium” are also used to produce more durable products with enhanced qualities such as: greater formability, resistance to scratches, or resistance to rust, etc.
Global production of crude steel has more than doubled over the last two decades, with production rising to “1.86 billion” tons in 2020. Among the noteworthy observations is that large production sites have moved over the years from Europe, the United States, and Japan, which used to represent a percentage of up to (53%) of global production, to emerging markets, which currently represent more than 70 percent of production.
Sustainability and iron and steel industry
Although the energy needs required to produce each ton of steel have decreased over the past two decades, the growth in production rates is a result of increased global demand. It has led to a steady increase in the total energy consumption of this vital industry; Consequently, carbon dioxide emissions and Greenhouse Gases (GHGs) in general increased, which prompted many iron and steel manufacturers around the world to research, develop, and experiment with new technologies in manufacturing processes. With the aim of confronting these challenges, by applying the principles of sustainability through the following methods:
1- Recycling
Steel scrap generated during manufacturing processes can be collected, in addition to the steel found in various products at the end of their lifespan, for example: structures that are demolished, cars that are no longer usable, or the recovery of metals in various machines and equipment, as global steel recovery rates from products at the end of their lifespan reach an estimated rate of (90%) for both cars and machines, (85%) for construction, and (50%) in electrical and household appliances.
Steel is characterized by the fact that it can be continuously recycled without any deterioration in its properties, which in turn means saving raw materials, reducing material and energy consumption, and reducing emissions, thus achieving a number of Sustainable Development Goals (SDGs), and a practical application of the principle of the circular economy.
Globally, the recycled content in steel production can rise with increased growth in production, but relying on scrap recycling alone will not represent a sufficient solution; Due to the increasing global demand for iron and steel, in addition, many products containing iron and steel can remain valid for decades, which means that the metal cannot be recovered from them.
It should be noted that the full realization and application of the principle of iron and steel recycling requires an effective effort from various parties. To provide appropriate collection systems, as well as the necessary infrastructure for recycling operations, in addition to shifting the industrial process to the use of electric arc furnaces, which we will discuss in the next point.
2- Transforming production processes
Most iron and steel are produced in blast furnaces or basic oxygen furnaces
(Basic Oxygen Furnace), which requires the use of iron ore and coal in the form of coke, but this method of producing steel is very energy intensive; And therefore in the amount of emissions.
Factories using blast furnaces and basic oxygen furnaces are widespread in many countries of Europe and Africa, despite the increasing number of manufacturers turning to the Direct Reduced Iron method, also known as sponge iron, with the use of Electrical Arc Furnaces. This method relies on natural gas and electricity as an energy source, and scrap steel, reduced iron, or a mixture of the two is used as a raw material instead of Iron ore.
The sponge iron and electric arc furnace method is characterized by the fact that the resulting emissions and energy consumption are lower by a third and a fifth when compared with blast furnaces and basic oxygen furnaces, respectively. Not only that, but electric arc furnaces that use scrap steel as a raw material can reduce their energy consumption by (85% and 90%) when compared with blast furnaces and basic oxygen furnaces, respectively, but given that the quantities of scrap iron are insufficient – as we mentioned in the point Recycling – In addition to the fact that the scrap is sometimes not suitable for the production of some special types of steel, this method is not widely used.
Iron and steel companies are also conducting carbon capture and hydrogen experiments. With the aim of reducing or eliminating carbon emissions, and if these technologies can be successfully applied on a large scale in the iron and steel industry, they could prove to be transformative in other industries as well.
3- Green hydrogen to reduce blast furnace emissions
Hydrogen is essential in the production of steel where it acts as a reducing agent, but it requires a large amount of energy to produce. Today, most of the hydrogen required for the industrial process is produced by natural gas using a process called methane steam reforming, an energy-intensive process that generates carbon monoxide and carbon dioxide as byproducts in large quantities.
Hydrogen can also be produced by splitting water molecules using an electrochemical reactor, what is known as “green hydrogen,” as this method produces oxygen as the only byproduct. By using electrolysis powered by renewable energy to isolate hydrogen from water, the green hydrogen production process becomes carbon-neutral, but this requires a reliable source to deliver renewable energy at affordable prices; In order for the method to be economically feasible to spread widely among iron and steel manufacturers; Thus, incorporating green hydrogen represents one of the promising solutions to achieve a low-carbon steel industry.
In addition to the above, hydrogen can be used in blast furnaces to replace coke, which can be reduced by up to about 20%. Hydrogen can also be used as an alternative reducing agent in the making of direct reduced iron, which can then be processed into steel in an electric arc furnace, a method that produces nearly carbon-neutral steel.
4- Green contribution in other sectors
Iron and steel contribute to a large number of key industries that help drive the green transition, as steel represents a main material used in building the equipment needed to supply the world with renewable energy such as: hydroelectric power, wind, and solar energy. For example, a wind mill (tower and rotor) is made of 80% steel.
Steel is also critical to the energy efficiency of buildings, factories and electric cars, and can help improve the sustainability of traditional goods. For example, the use of advanced types of high-strength steel can reduce the structural weight of cars by up to 25%, which helps reduce their carbon dioxide emissions cycle.
Challenges and opportunities in the iron and steel industry
Steelmakers have reduced energy use in recent years; Consequently, carbon emissions were reduced through technological innovations based on developing production processes, but these efforts still require more and more to reduce the carbon footprint of this industry in the future.
The global iron and steel industry bears a great responsibility; This is so that it can be in line with the goals of the Paris Climate Agreement. In order to contain global warming below 2 degrees Celsius, this industry must reduce its carbon emissions by more than half by 2050, while continuing to reduce emissions after that until reaching “zero” emissions.
In the near term, iron and steel manufacturers using blast furnaces can improve energy efficiency by up to (20%) per ton, by adopting new technologies and improving operation, in addition to using waste heat recovery systems, whether in new factories or those already existing, along with supplying the blast furnaces with top-pressure recovery turbines, which use the heat and pressure generated by the blast furnace to generate Electricity.
Another opportunity is to promote greater reliance on scrap, when available, as an alternative raw material to iron ore in blast furnaces and basic oxygen furnaces, which would significantly improve energy efficiency.
On the other hand, it is expected that during the coming years the threshold limits will be lowered by the governments of a number of countries in Europe and America for emissions from the iron and steel industry, in addition to the intention of some countries to impose restrictions regarding the carbon footprint of iron and steel imported from abroad, and this will put iron and steel manufacturers in front of a major challenge to adopt sustainable technologies on a broader scale.
