Decarbonization of Iron and Steel Production

Technologies for industry and agriculture

Steel is the third most abundant man-made material on earth and is used in numerous sectors, including, the sector of construction, infrastructure, transport, machinery and consumer goods.  Steel production covers about 8% of global energy needs and 7% of total carbon dioxide emissions. In 2020, about 1.9 billion tons of steel were produced and 2.6 Gt of CO2 were emitted [1] .

Current technologies for steel production are (i) the integrated cycle with blast furnace (BF) and oxygen furnace (BOF, Basic Oxygen Furnace) and (ii) electric arc furnace (EAF) technology for the smelting of ferrous scrap. For the production of iron, alternative technologies to blast furnace production are based on processes of direct reduction with natural gas (MidrexTM, EnergironTM) or with coal (RedironTM FastmetTM, SL/RN) and subsequent smelting in EAF or by smelting (Redsmelt™, Corex®, Finex®) of the ferriferous material (direct production of cast iron). In the European Union (EU28) in 2020, about 57.6% of steel was produced through a basic oxygen furnace (BOF), while the remaining 42.4% is produced with Electric Arc Furnace (EAF). The only two EU28 countries where steel production comes mostly from the EAF process are Italy and Spain, in particular Italy produces 84.7% of steel from EAF and the remaining 15.3% from BOF [2].

Several options have been identified for the decarbonisation of iron and steel production that affect both direct emissions from the combustion of fossil fuels commonly used for high-temperature heat production and indirect emissions. The main categories of actions identified by the IEA in [1], there are: 1) technologies for energy efficiency and best available technologies – BAT; 2) carbon capture, storage and utilization technologies  – CCS / CCU that allow the capture of emissions produced with particular attention to process ones; 3) Fuel switching technologies  such as use of hydrogen in DR and blast furnace (BF) processes and the use of biomass in processes including the blast furnace and finally 4) the direct electrification of the production process by low or high temperature electrolysis.

CCS systems allow the separation of CO₂ through physical adsorption or chemical absorption from combustion gases (e.g., exhaust gases from power plants subservient to the production cycle, cowper exhaust gases) or from off-gas produced in steel plants (e.g., blast furnace gas, coking plant gas). At European level, the Ulcos (Ultra Low CO₂ Steelmaking) project is the largest project for the decarbonization of steel and iron production. Some of the issues considered by this project are the decarbonization of the BF-BOF integrated cycle through the TGR (Top Gas Recycling) technique, the decarbonization of a process of direct reduction (Ulcored) and reduction by fusion (Hisarna). One of the most important European initiatives for the decarbonization of the sector was the inauguration in September 2017 of a module for the separation of CO₂ through a physical adsorption on solid sorbents at high temperature (SEWGS process: Sorption Enhanced Water Gas Shift). The installation of the SEWGS module in the Mefos research centre in Lulea (Sweden) was one of the main results of the European Stepwise project. To date, in Italy there are no steel plants equipped with CCS technologies

29-07-2022

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