The subject of the efficiency intervention was the aluminium scrap treatment plant in operation at a well-known foundry, which produces raw material in the form of aluminium ingots mainly for the die casting industry. The project developed the recovery of thermal energy contained in the high temperature fumes leaving the heat treatment cycle to which the aluminium scrap is subjected before it is destined for melting. The thermal energy recovered from the fumes of a post-combustion unit has been reused within the same process to preheat the combustion air of the burners at the service of the post-combustion unit itself and to inject preheated air directly into the drying drum, i.e. the plant in which the scrap is treated by pyrolysis.
Under ex-ante conditions, all the heat required for the described processes was produced through direct combustion of natural gas.
Results obtained:
- Thermal energy saving: 7.752.000 kWh/year (1.157 kWt for 6.700 hh)
- Primary energy saving: 795 Toe/year
- Saving of natural gas: 950.000 scm/year
- CO2 not released into the atmosphere: 1.852 tons/year
- Payback intervention: about 12 months
The system has been equipped with a monitoring system able to measure and historicize the post-intervention consumption. This is essential for taking stock of and verifying the energy savings achieved.
The intervention has been analysed, designed and implemented by RENOVIS.
