WP 3 targets RO4, to develop measuring and analysis tools and models to support the application of hydrogen-based processes in the carbon-steel and stainless-steel production routes. This target is addressed in two ways in HELIOS. Firstly, we are aware that hydrogen-plasma is a very powerful reductant, but the effectiveness and efficiency of the reduction process can be limited by the plasma state and stability. To this extent, we aim with HELIOS (1) to develop advanced online tools to monitor the HPSR; and (2) to correlate the reduction degree with the plasma state. DC8 at Hereaus Electro-Nite will develop a sensor and the instrumentation to continuously measure dissolved gases, in particular hydrogen, in liquid steel during the HPSR process. This will include research in various technologies capable to measure hydrogen in liquid steel, developing a suitable robust sensor and instrumentation package and developing and designing a refractory system capable to work in the high temperature liquid steel environment. In addition, DC8 will investigate and develop temperature sensors and sampling systems specifically suited for HPSR. Together with the developed gas sensors instrumentation, this will result in a complete novel sensing system required for optimization of the HPSR process. DC9 at the University of Oulu will focus on the characterization of the HPSR of iron oxides with empirical data from in-situ monitoring methods such as optical emission spectroscopy (OES) and camera images and with process data. Pre- and post-process analysis of reduction degree and composition of the samples will provide the starting point to study the reduction degree. DC9 will seek to identify the process steps from the data and to characterize the state of both the plasma and reduction degree during the smelting. By changing the process parameters, such as electrical input, length of the plasma arc, and gas composition, DC9 will build up a database describing how the process changes with different starting points. As the knowledge of the process improves, DC9 will explore ways to optimize the reduction process so that power input, H₂ consumption, and/or the time that the reduction takes will be reduced.

Finally, it is crucial to develop suitable models to perform a sustainable and economic assessment of the processes considered in HELIOS. DC10 at the KU Leuven will evaluate the environmental impacts by a full lifecycle assessment (LCA) and benchmark them with current carbon-steel and stainless-steel production routes, thereby also considering upscaling of the technology. The economic viability will be assessed by life cycle costing (LCC), yielding NPV of the routes under development. Both methodologies will be integrated by DC10 in an ex-ante sustainability assessment via multi-criteria decision analysis to simulate alternative future performances of the steel production routes via multiple scenarios. Finally, DC10 will set up the LCA as a consequential LCA, by partial equilibrium modelling of the possible shifts in steel markets in Europe and including these in the boundaries of the LCA. DC10 will interact closely with the other DCs, for input to the models and for discussing a possible remediation of environmental and economic hotspots in the design of steel production routes.