Recirculating off-gas contributes to carbon capture
Producing silicon results in large carbon dioxide emissions, but recirculating it can remove contaminants more efficiently.
Operators from Elkem Thamshavn are shown tapping liquid silicon from the furnace. Photo: Vegar Andersen
Every tonne of silicon we produce leads to emissions of around 5 tonnes of CO₂.
Carbon capture offers a possible solution to eliminate this emission, but the CO₂ concentration in the off-gas from the furnaces is often too low for CO₂ capture to be cost-effective.
One possible solution to reduce the cost is to increase the CO₂ concentration by recirculating the off-gas. The silicon manufacturer Elkem has collaborated with NTNU and SINTEF to test this idea in a pilot project.