Considering the flue gas temperature (between 300°C and 400°C), FerroPem and Dalkia selected a technical solution based on an ORC (Organic Rankine Cycle) for the WHIN project.
- Flue gas exhausted by furnace N.1 at the Anglefort site is collected upstream the cooling ducts through a connection equipped with dampers.
- The flue gas is headed to the heat exchanger, where the heat transfer fluid loop passes through, and it goes back to the flue gas duct, downstream the cooling ducts.
- Since the flue gas has not been filtered prior to passing through the exchanger, the dust rate is very high. Therefore, the exchanger must be equipped with an automatic shot blasting machine.
- The working fluid especially allows reducing by 99% the Global Warming Potential (GWP) against that of the fluorinated refrigerants resulting from the state-of-the-art technology. This fluid is vaporized as it passes through the heat exchanger. It is then used as part of the Organic Rankine Cycle.
- The steam produced is expanded in a turbine in order to produce mechanical work and then electricity by means of an alternator that will convert such mechanical power into electrical power. The expanded steam is condensed to close the thermodynamic cycle, and thus work in closed circuit.
92% of the time, all year round, the recoverable heating capacity is about 20 MW. The output capacity of the ORC (3.9 MW (installed capacity)) shall allow generating more than 22 GWh of electricity per year, i.e. the average electricity consumption of 4,500 housing units equivalents.
Innovation and environmental impacts
- In France: first ORC unit with a capacity of more than 3 MW (installed capacity)
- Worldwide: first installation of heat recovery from an open furnace in the silicon production industry
- Industrial application of a new working fluid for power generation plants with an environmental impact 100 times less than the newest technologies
- A 26% cut in CO2 emissions thanks to green energy production (waste-to-energy)
- 47% of exhaust heat from the silicon metal production is recovered
- Positive social and economic impacts at local level resulting from an enhanced competitiveness of the industrial site
- Strengthening the region’s leadership on energy and innovation, through a world’s first approach considering both: its size and its scope.