The Route to Combustion Technology for the Decarbonization Age
The Route to Combustion Technology for the Decarbonization Age
Tenova standard approach for burner development/improvement cycle. Image: Tenova Italimpianti
Steel industry has set ambitious goals of reducing its greenhouse gas emissions in a relatively short time frame. To reach their targets, the iron and steel producers need a paradigm shift to fulfil environmental regulations and to evolve their processes towards low-carbon footprint technologies without losing competitiveness or profitability. To this end, both steel production stages, Upstream (up to liquid steel) and Downstream (from liquid to solid steel), need to implement an evolution or replacement of standard technologies.
More than 40 % of European steel comes from scrap recycling with direct carbon emission intensity of about 150 kgCO2e/ton for the Upstream portion. In this case, reheating and heat treatment processes in Downstream with direct emissions of 50-200 kgCO2/ton cover a relevant fraction of total direct carbon intensity of steel products. Consequently, the decarbonization of the steel recycling route must take into account low-carbon heating solutions. In this energy transition scenario, Tenova proposes a stepwise approach to the decarbonization of heating furnaces. After a first step of efficiency optimization, direct or indirect electrification is pursued as much as possible to minimize the energy consumption. This is possible only up to a critical temperature, where other process constraints (scale formation, heating efficiency, production flexibility) come into play. Hydrogen and non-fossil fuels combustion are thus required for the final heating range at high temperature, also because they provide a protective atmosphere against surface oxidation.