The work carried out consists in recovering the heat contained in the fumes of four 20 t/h steam generators.
In particular, it is proposed to recover the thermal energy contained in the exhaust fumes leaving the steam generators and reuse this obtained no-cost heat for:
- Preheat the boilers' feed water.
- Preheat the make-up water of the boilers themselves.
This recovery can be obtained through a system divided into several stages of air/water heat exchange.
The first recovery stage (ECO): involves using the heat contained in the flue gases leaving each of the steam generators to preheat the feeding water.
A brand new heat recovery plant (RC2) has been built at steam bolier #4. This involves using the residual heat contained in the flue gases leaving the first stage (ECO) to preheat the make-up water for the overall steam boilers room.
The heat recovery stages guarantee a considerable saving of natural gas.
Results obtained:
- Thermal energy saving: 4.830.000 kWh/year
- Primary energy saving: 378 Toe/year
- Saving of natural gas: 457.800 scm/year
- CO2 not released into the atmosphere: 894 tons/year
- Payback intervention: about 30 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.