HyInHeat: EU project for the use of hydrogen in the aluminium and steel industry

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HyInHeat – Hydrogen technologies for decarbonisation of industrial heating processes – this is the name of the new large-scale project that has been launched with 28 partners from 12 European countries. The project focuses on the use of hydrogen in the aluminium and steel industries, with the overall aim of making a valuable contribution to the decarbonisation of the industries: The research project, which is funded by the EU with 17.7 million euros, is investigating how the efficient use or combustion of hydrogen can be integrated into the heating and melting processes and thus make an important contribution to decarbonisation along the process chains of these sectors. The project is coordinated by the Institute for Industrial Furnace Construction and Thermal Engineering (IOB) at RWTHA.

The main goal of the EU project is to integrate hydrogen as a fuel for high-temperature heating processes in energy-intensive industries. This is because, especially in energy-intensive processes of melting and heat treatment, the replacement of fossil fuels with green hydrogen holds great potential for saving CO2. In order to counteract the initial lack of widespread availability of large quantities of green hydrogen, operation in a fuel mix of natural gas and hydrogen up to pure hydrogen is being investigated. Another focus is on combustion with pure oxygen, which is a secondary product of green hydrogen production via electrolysis and enables an increase in combustion efficiency.

Hydrogen for decarbonisation of the aluminium and steel industry

As part of the work packages covered by the project, the influence of impurities in the fuel on the instrumentation of the gas supply and burner operation will be tested in the IOB's in-house technical centre. The changed conditions in the flue gas due to the increased water content are analysed with regard to the necessary adjustments in the field of emission measurement technology. The conventional measurement of nitrogen oxide emissions in dry exhaust gas is being questioned in this context and alternative measurement principles are being tested. In the area of modelling and simulation, the activities concentrate both on the mapping of individual burners and on the mapping of entire furnaces, including the products and peripheral plant components. In addition to direct heating in melting furnaces for the aluminium industry and heating furnaces for hot forming of steel, indirect heating with radiant heating tubes is also being investigated. For the simulation, the increased water content in the flue gas results in different conditions compared to natural gas, so that suitable models for radiant heating are evaluated. A reasonable numerical effort is achieved by Reynolds Averaged Navier Stokes (RANS) simulations, which are solved on the partly newly created server capacities at the IOB. The methodology is validated against the accurate LES simulation results and data from the laboratories and industry demonstrators. The simulations support the design of burners, furnace processes and the conversion of existing plants to run on hydrogen. In parallel, the life cycle assessments of the processes and products are continuously evaluated to ensure the achievement of the overall project goal: To make a noticeable contribution to the decarbonisation of the steel and aluminium industry.

Full power for the project: 28 strong partners from 12 countries

The partners from 12 European countries include not only steel producers, but also various large companies from the aluminium sector. The automotive industry is also represented, and gas suppliers, technology providers and furnace manufacturers are also involved. The European associations ESTEP and European Aluminium are contributing by collecting and providing data for scenario analyses and helping to disseminate the results.  In addition to the companies and associations, four research institutions are involved and, on the university side, RWTH Aachen University itself is also represented by three institutes: The Institute of Mineral Metallurgy (GHI) is dedicated to refractory furnace materials. Samples from industrial plants as well as newly developed materials are examined for their interaction with the new furnace atmospheres, which change in terms of temperatures and atmosphere compared to combustion with natural gas. The Institute for Technical Combustion (ITV) provides the kinetic reaction mechanism for hydrogen combustion after test series in the institute's own spherical combustion chamber, which reproduces the combustion reactions in subsequent CFD simulations. In the research facilities, a methodology for the large-eddy simulation (LES) of hydrogen combustion is also being developed, through which the flame dynamics can be predicted under given operating conditions.