Programme nominated for the Excellence in Low-carbon Steelie Award 2023
Brazilian integrated long steel producer, AVB has a production capacity of 600.000 tonnes per year and generates more than 2,700 direct jobs.
The melt shop’s scrap pre-heating system, using blast furnace renewable process gas, has as the main objective to increase the amount of scrap loaded in the BOF (basic oxygen furnace), in addition to increasing safety, production capacity and reducing CO2 emissions.
This system was developed by the AVB team and consists of equipment where the scrap to be loaded in the BOF is stored in a box absorbing all the sensible heat of the hot gases coming from the controlled combustion of blast furnace gas in a special chamber coated with refractory material. An automated blast furnace gas combustion control system was developed to eliminate smoke and emissions into the atmosphere.
A carbon monoxide (CO) meter and a thermocouple are placed to measure and control the scrap temperature next to the preheater.
The implementation of this technology only makes sense for plants where gas is available, cheap and generated by a renewable source, such as biomass.
The scrap preheating process allows:
- The increase in the scrap surface temperature to be loaded (greater thermal input) inside the BOF from 25˚C to 500-600˚C;
- The increase in the percentage of scrap loaded in the BOF from 12% to 30% (average 27%) with a focus on increasing the recycling (circular economy);
- The increase in steel production capacity of more than 100,000 tonnes per year due to the greater use of scrap in the BOF and, consequently, higher casting weight (tonnes per heat);
- Increased operational safety by reducing the risk of reactions inside the BOF with liquid steel projections due to the loading of wet scrap.
AVB has achieved the milestone of low-carbon emissions steel production based on the long-term strategic vision of the shareholders, who predicted the production of green and sustainable steel as a fundamental and differentiated value for the future growth and perpetuity of the company.