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Algae reduce greenhouse gas emissions

Can algae cultivation reduce greenhouse gas emissions from the metals industry? This is a question being studied by RISE in a joint research project being conducted with Swedish mining and smelting company Boliden.

The project, which examines the cultivation of microalgae for the purification of process emissions in the metals industry and is financed by the Swedish Energy Agency, will run for two years at Boliden Bergsöe’s lead smelting plant in Landskrona.

“We need metals for a wide range of technical applications, such as batteries, electronics and building materials for a growing population, while at the same time we must reduce greenhouse gas emissions,” says Oskar Schlyter, project manager, Central R&D at Boliden Bergsöe.

The project is based on a waste heat and flue gas-based method for growing algae that has been developed by the algae group at RISE. The method has already been tested industrially at Nordic Paper Bäckhammar’s paper mill, where it was used to clean flue gases and produce energy.

The algae cultivation method mimics the natural processes behind the formation of fossil carbon, in particular oil. In the industrial version, flue gas is fed from a chimney into basins filled with water and microalgae, a process that rapidly produces biomass, primarily from the carbon dioxide content of the flue gas. In their dry state, the algae function as an energy carrier and can be used to power smelting processes at smelting plants. On incineration, the algae biomass returns the metals that were previously in the flue gas to the molten metal, while energy, clean water and flue gas are extracted simultaneous to the production of metal ingots.

“We expect the concept to be able to deal with CO2 emissions, create energy for smelting, and also remove metal emissions from flue gases,” says project manager and RISE researcher Niklas Strömberg.

“Although algal cultures are effective at binding carbon dioxide, their cultivation requires large areas. This project is therefore important in that it allows us to assess the impact of such cultivation and the potential for reducing CO2 emissions, eutrophication and the dispersal of heavy metals, while at the same time evaluating whether algal biomass has potential as a fuel for Swedish heavy industry,” concludes Niklas Strömberg.

Published: 2018-10-29