Green Hydrogen-Based Direct Reduction for Low-Carbon Steelmaking

The European steel industry aims at a CO2 reduction of 80–95% by 2050, ensuring that Europe will meet the requirements of the Paris Agreement. As the reduction potentials of the current steelmaking routes are low, the transfer toward breakthrough-technologies is essential to reach these goals. Hydrogen-based steelmaking is one approach to realize CO2-lean steelmaking. Therefore, the natural gas (NG)-based direct reduction (DR) acts as a basis for the first step of this transition. The high flexibility of this route allows the gradual addition of hydrogen and, in a long-term view, runs the process with pure hydrogen. Model-based calculations are performed to assess the possibilities for injecting hydrogen. Therefore, NG- and hydrogen-based DR models are developed to create new process know-how and enable an evaluation of these processes in terms of energy demand, CO2-reduction potentials, and so on. The examinations show that the hydrogen-based route offers a huge potential for green steelmaking which is strongly depending on the carbon footprint of the electricity used for the production of hydrogen. Only if the carbon intensity is less than about 120 g CO2 kWh1 , the hydrogen-based process emits less CO2 than the NG-based DR process.