Advances in Primary Ironmaking and Steelmaking Processes
In the recent past, ironmaking and steelmaking saw the incorporation of various new processes and technologies that can be operated and organized in different combinations depending on the properties of raw materials and the required quality of the final products. Different raw materials, energy requirements, and investments can vary as a function of different plant configurations and the advanced technologies employed for to reduce emissions. Due to the low level of restrictions and international protocols active during the last 15–20 years, innovation has been growing so fast that knowledge of the best available technologies is fundamental for scientists and industrial operators.
Indications from the steel industry and local and global government institutions are that the breakthrough technologies for decarbonization will be based on hydrogen reduction. The employment of hydrogen in the ironmaking and steelmaking industries will push forward the global transformation of hard-to-abate industries. Given that the two main routes for primary steel production decarbonization will almost certainly be CCS (carbon capture and storage) and hydrogen-based reduction, public and private R&D spending, as well as investment in pilot plants, should focus on driving down their cost and increasing the efficiency of equipment and piloting and driving down the cost of hydrogen-based reduction.
For CO2-lean process routes, three major solutions have been identified: decarbonizing, whereby coal would be replaced by hydrogen or electricity in the hydrogen reduction or electrolysis of iron ore processes; the introduction of CCS technology; and the use of sustainable biomass.
Through a hydrogen-based steelmaking route, CO2 emissions would be reduced by more than 80%. Hydrogen steelmaking will depend profoundly on the availability of green hydrogen, which can be generated from natural gas by steam reforming, or from water by electrolysis. Today, hydrogen-based steelmaking is a potential low-carbon and economically attractive route, especially in countries where natural gas is cheap. In considering systems for increasing energy efficiency and reducing the environmental impact of steel production, CO2 emissions may be greatly reduced by hydrogen-based steel production if the hydrogen is generated by means of carbon-free and renewable sources. Currently, the development of the hydrogen economy has received a great deal of attention in that H2 is considered a promising alternative to replace fossil fuels. If H2 is utilized as an alternative fuel, not only can the problem of the progressively exhausted fossil fuel reserves be solved, but the atmospheric greenhouse effect can also be mitigated. Based on hydrogen, the “hydrogen economy” is a promising clean energy carrier for decarbonized energy systems if the hydrogen used is produced from renewable energy sources or coupled with carbon capture and storage (CCS) or nuclear energy.
