Fastarc Zero

The Danieli EAF equipped with ECS system is named FASTARC 0, with clear reference to the Zero Bucket Charging process, meaning that there is no more bucket charging required in scrap melting.

The scrap is conveyed into the EAF continuously and melted by contact with the liquid steel. The arcs transfer power to the liquid steel to keep the melting temperature in a very stable operating condition (flat bath), with arc always properly covered by foaming slag.

This provides a much better exploitation of the electrical power and a much higher average/maximum power ratio, thus resulting in a faster melting.

In addition, thanks to the preheating up to 400°C, the scrap enthalpy contributes to reduce the melting energy required up to -50 kWh/t.

The furnace never stops for bucket charging. This minimize the power off and reduces the energy losses due to roof opening.

In addition, the power utilization is more efficient compared to batch processes and the amount of energy is lower thanks to the preheating of the scrap.

The combination of these benefits provides a much shorter Power-On time, so the productivity is sensibly increased compared to conventional furnaces.

The short TTT, the high reliability and repeatability of the continuous process and the simplified logistic (no bucket handling) allow the EAF with ECS to reach very high number of heats per year.

As no bucket charging is required, the FTP secondary suction capacity can be conveniently reduced. This provides smaller FTP system and much less dust generation.

— Best environmental impact: 

The design of the preheating section ensures that the temperature of the fumes is kept always above 700°- 750 °C. This temperature avoids reformation of dioxin and destroys other pollutants, such as VOC and organic carbon. The emissions of VOC and dioxin of the ECS are therefore comparable with bucket furnaces.

The VOC, dioxin and organic carbon is a severe problem in all the vertical shaft preheaters, due to the low temperature of the fumes out of the shaft, which can promote dioxin emission and problems with the filtering system.

The VOC emission of a vertical preheater is 3 – 4 times higher than the ECS ones!

To avoid this, the vertical shaft preheaters require significant injection of chemical energy in the combustion chamber (14-15 Nm3/t of Natural Gas). VOC coming out of the furnace require a post-combustion system with natural gas to raise the temperature and thermally destroy the pollutants.

— Greenhouse gases emissions

According to the recent ISO 14404 standard [3], the equivalent carbon dioxide is referred to the energetic sources (electric, thermal by gas) directly used during the specific process, e.g. scrap melting, and to the energy employed to extract, produce and transport all prime materials connected with production, e.g. carbon, slag builders, refractories.

This approach keeps into account with the best accuracy all mechanisms contributing to increase the global warming effect.

Considering the case of a 100-ton heat size electric arc furnace, it can be determined a generation of equivalent CO2 close to 310- 315 [kgCO2/ton] with the ECS® furnace.

At equivalent conditions, a scrap bucket furnace would produce almost 340 [kgCO2/ton].

Finally, a vertical preheating system, characterized by a lower electric consumption but a higher additional use of natural gas, gets to 355-360 [kg- CO2/ton].