In the course of the development of the hydrogen plasma smelting reduction process (HPSR) it is of great importance that the thermally stressed parts of the plant are optimally designed. One of the core topics in this area is the design of the refractory material for the lower vessel of the system, which is necessary to capture the liquid metal that is produced. Due to thermal and chemical processes, very high demands are placed on this relining. On the one hand, this is the high thermal load from the radiation of the plasma flame and the chemical attack by the high FeO-containing slag. It also appears that the oxidized refractory material is reduced by unused hydrogen.
Another critical point is the utilization of hydrogen. It cannot be expected that all of the hydrogen injected will be used for the reduction of iron ore. Thus, a certain amount escapes together with the water vapor. The aim is to minimize the amount of unreacted hydrogen, to separate it and to develop a concept for recycling unused hydrogen.
It must also be ensured that hydrogen is available in the required amount. A concept for the continuous generation and storage of hydrogen is therefore being drawn up. Depending on the energy mix of the power generator, CO2-free hydrogen should be generated for the HPSR system.
Objectives and Motivation
- Increase the durability of the refractory material in the reactor vessel by
- Selection of suitable materials
- Adjustment of the process slag
- Formation of foamy slag
- Concept for a water electrolysis, hydrogen storage and a hydrogen recirculation from the exhaust gas of the HPSR process
Appropriate materials (high-alumina or spinel-forming) are to be developed at the RHI research center in Leoben. These can then be tested in the laboratory plasma furnace at the Chair of Iron and Steel Metallurgy at the MUL under various process conditions. Based on the results, the refractory will be tested by K1-MET in the HPSR reactor at voestalpine Donawitz site. At the same time, tests are carried out with different slags in order to investigate their influence on the refractory material. Finally, a foamy slag will be generated by injecting gas through an installed bottom purging system. This foamy slag should protect the relining from high thermal impact.
The conceptual design of the electrolysis system will demonstrate the state of the art of hydrogen production using renewable energy. Subsequently there will be results for the storage of hydrogen as well as the return of unused hydrogen from the exhaust gas. This will increase the efficiency of the process.
For this, it is necessary to set up an overall system simulation of an electrolysis and fuel cell module (preferably in Matlab / Simulink). The overall system is designed based on simulation results from K1-MET in cooperation with Fronius. A parameter study with subsequent efficiency analysis defines the optimal operating conditions such as pressure, temperature, number of cells, H2 storage volume, etc.) The comparison of different concepts (e.g. high-pressure electrolysis vs. electrolysis at ambient pressure with downstream compression) is also part of the project.
From these results, an optimized concept for partial load (e.g. 50% load) and for full load will be engineered. As part of the optimization the development of an efficient control system for dynamic operation (electricity price-driven, H2-demand-driven) will be promoted too.
Results and Application
The refractory material is optimized for the prevailing conditions in the reactor vessel. In this context, it is important to test a variation in slag composition in order to determine a minimum of refractory wear. To further protect the refractory material, an attempt is made to generate foamy slag by installing a bottom purging system. This is to protect the relining from the enormous thermal radiation of the plasma arc.
Finally, an overall concept for large-scale steel production using HPSR including the infrastructure (production, storage and recycling of hydrogen) will be engineered.