Johannes Kepler University Linz and VOEST ALPINE Industrieanlagenbau GmbH

The process of steel production from scrap with an electric arc furnace (EAF) involves a high-temperature melting process that produces huge amounts of dust-laden gas. The heat emission from the furnace forms a highly turbulent buoyant plume.

Dedusting systems are attached to the EAF in order to minimize emission from the EAF, and are located in a ventilation hood (canopy) above it, in order to clean the air in the plant.

Researchers at the Johannes Kepler University in cooperation with VOEST ALPINE Industrieanlagenbau GmbH (both in Linz, Austria) used FLUENT to evaluate and improve hood ventilation systems in industrial facilities, with a focus on EAF melting shops. With the help of these simulations they were able to determine optimum operating conditions (such as suction rates) and improve ventilation performance by design modifications of the canopy hood and the crane/trolley arrangement.

One method for evaluating dust concentrations in the plant involved the use of a special drift flux model accounting for sedimentation effects2, which was implemented by user-defined scalar (UDS) equations. Natural convection and the influence of turbulence on dust dispersion were fully included. A discrete spectrum of dust particle sizes (representative of a measured spectrum) was modeled, with particle sizes ranging from 0.1 to 100 microns. Results of the analysis indicated that the larger particles settle in the vicinity of the EAF, but smaller particles (1 micron) disperse throughout the entire plant. FLUENT was deemed to be a powerful tool in the analysis and redesign of ventilation and dedusting systems (both in terms of fan power and configuration geometry) in steel melting facilities.

References:
1 R. Kickinger, P. Gittler, M. Javurek, J. Lehner: ‘Ventilation and Dedusting Of Melting Shops’, Proceedings of the Second International Conference on CFD in the Minerals and Process Industries, 6-8 December 1999, CSIRO, Melbourne, Australia.

2 This model was implemented with financial support from VOEST ALPINE Stahl Linz GmbH, Austria.

A plume of dust particles rises from the EAF. Large particles are trapped by nearby suction units, but small particles (1 micron) disperse throughout the plant.

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