Sustainable EAF steel production
In the modern electric arc furnace (EAF) more than 40% of energy comes from chemical sources by fossil fuels: natural gas is used in dedicated burner during the melting of the scrap while coal (mainly anthracite), lump in the basket and pulverized by wall injector, is used as foaming agent. In the frame of the European Research Fund for Coal and Steel (RFCS), project GREENEAF, was carried out with the objective to replace coal and natural gas in EAF with char and sysngas produced by biomass pyrolisis.
Generally speaking, in the electric furnace coal (and consequently char) is used as injected powder or charged into the basket. The syngas can be used for EAF burners.
The characteristics of char and biogas, and the related pyrolysis process, are tailored in order to match the requirements for their utilization in EAF. The following activities have been carried out within the project:
- Biomass selection and classification respect their origin and characterisation activities
- Tailoring of biomass pyrolysis: Laboratory tests to define the pyrolysis kinetics of the selected biomass, and on the basis of these results design of industrial pyrolysis; then chemical and physical characterization of char produced by biomass pyrolysis has been carried out to define pyrolysis plant process parameters. About fifteen tons of char has been produced for industrial trials
- EAF pilot plant experimentation: First tests of char utilization have been carried out in the pilot Furnace
- Industrial experimentation: industrial tests with char have been carried out
- Simulation of syngas utilization: due to the difficulties to have syngas available close to the steel plant syngas utilization for EAF burners has been simulated by CFD calculation.
The results obtained have demonstrated the technical feasibility of the used approaches while the economical evaluation have showed the sustainability of replacing the coal with char from biomass, in addition to environmental benefits due to CO2 reduction, even if at the moment there is not a real assessed market of charcoal for steelmaking purposes.
Bianco, L.; Baracchini, G.; Cirilli, F.; Moriconi, A.; Moriconi, E.; Marcos, M.; Demus, T.; Echterhof, T.; Pfeifer, H.; Beiler, C.; Griessacher, T.: Sustainable EAF steel production (GREENEAF), EUR 26208, Publications Office of the European Union, (2013), Luxembourg, ISBN 978-92-79-33614-0
The research leading to these results has received funding from the European Community’s Research Fund for Coal and Steel (RFCS) under grant agreement n° RFSR-CT-2009-00004.