Heat Recovery Boiler from Electric Arc Furnace Flue Gas

In 2021 a large steel company in Los Barrios (Cadiz, Spain) implemented a plan with the aim of decarbonising its production process and reducing its operating costs. The project included recovery of heat from the hot fumes produced from an electric arc furnace.

Design, supply and commissioning of a forced circulation water-tube boiler to generate 11 t/h of saturated steam at 8 bar, corresponding to a power of 7.5 MWt.

The forced circulation design allows:

• Operation with temperature variations (inversion cycles every 20 minutes).
• Flexibility with the increase in thermal power as the furnaces age during the life cycle of the plant.

The high dust content of the fumes was one of the main challenges for this project. The dust particles can cause clogging of the boiler passageway section, which would lead to :

• A drastic increase in the pressure drop on the smoke side that can affect the normal operation of the furnace.
• Reduction of heat transfer rate therefore reducing steam generation capacity.

For this reason, the boiler is equipped with an in-line cleaning system (shot blast system) to keep the heat exchange surfaces clean and prevent fouling that reduces steam production and increases the flue gas pressure drop above the design value.

Thanks to the implementation of the heat recovery boiler, atmospheric emissions are reduced and fossil fuel consumption is reduced leading to cost savings.