Efficient supply with carbon dioxide from flue gas during large scale production of microalgae: A novel approach for bioenergy facades

Abstract

The efficiency of using enriched CO₂ from flue gas for large scale production of the green microalgae Chlorella sorokiniana in a bioenergy facade was studied. Using a membrane device, the enrichment of CO₂ from heating system flue gas in the low pressure product gas was up to 49 vol% and the CO₂ recovery was 62 %. With a static mixer the re-compressed product gas was applied to the culture medium with mean losses during cultivation of only 24 %. Thereby the pH could be maintained at a mean of 6.2 and a temperature always below 28 °C, both optimal for growth of Chlorella sorokiniana. Although PAR solar radiation during midday always exceeded 1000 µmol m^-2 s^-1 mean photosynthetic efficiency was 0.54 g mol^-1. Results indicate that the chosen approach for CO₂ supply overcomes the problem of CO₂ losses and allows for a more economic and sustainable microalgae production in a bioenergy facade.

Keywords: Bioenergy façade; CO(2) supply; Flue gas; Microalgae; Photosynthetic efficiency.