Cristiano Castagnola: As Maria said, the DRI plant will operate with 100 % hydrogen. This is a major breakthrough as today, all industrial DRI plants are operated with gases from fossil sources, mainly natural gas. The major difference in the setup of a plant conceived to operate only with hydrogen is that electrical process gas heaters replace the reformer. In a conventional natural gas-based MIDREX® DRI plant, the iron ores are reduced by hydrogen and carbon monoxide syngas. This syngas is produced by reforming the natural gas before sending it in the shaft furnace.
When operating a DRI plant only with hydrogen, you must heat up the hydrogen to increase the energy level for the chemical reduction needed to remove oxygen from the iron ore pellets to generate metallic iron. In H2 Green Steel’s MIDREX® plant, this is not done through a gas-gas heat exchange between the process gas and combustion generated off-gasses, as it is done in all industrial processes, and the reformer. Instead, we use a set of innovative large-scale electric heaters. This novel solution allows for significant energy savings, as it eliminates the need to transform electricity into hydrogen for gas heating, which is inevitably associated with yield loss.
Christian Geerkens: The electric arc furnaces are, of course, operated with electricity from renewable sources. That’s quite novel in and of itself. To reduce energy consumption in steelmaking, we will hot-charge DRI into the furnaces. It’s not the first plant in the world combining a DRI plant and EAF with hot-charging, but it’s very leading-edge. We will also have two energy recovery plants producing steam for the electrolyzers and downstream processes.
We have electrified most heating processes in the rolling mills and processing lines. For example, in the CSP® Nexus plant, we will replace the gas-fired tunnel furnace with a combination of induction heaters and electrically heated roller tables. Also, heating the cold rolled strip in the galvanizing lines is done with electrical energy instead of gas-fired burners. Last but not least, the batch annealing furnaces are also powered by electricity.