- Italcementi Group

Aiming at recovering and recycling CO2 produced by the clinker process, Gargenville plant, one of the ten cement plants of Italcementi Group in France, has started to cultivate microalgae. Microalgae can be extensively used to capture CO2 from cement plant and the resulting algal biomass can be used in oil production, converted into biodiesel or bioplastics, or act as a renewable replacement for coal when the latter is dry.
Gargenville microalgae is cultivated in a "photobioreactor" involving two glass tubes designed to achieve the right balance of light and CO2 feed. This sophisticated system implements the dissolution of CO2 coming from the chimney stack of the cement plant (through a dedicated sampling line) in a nutrient-rich culture medium. More the microalgae eat CO2, more they grow. As a matter of fact, like all green terrestrial plants, microalgae grow with photosynthesis and consequently, their development requires light (natural or artificial), CO2, water and some nutrients (mineral salts). To optimize the biological process the two glass tubes are firstly lighted up with an artificial light with temperature averaging around 25 degrees.

The second stage of this project will evaluate if the CO2 produced by the cement plant will have an impact on the microalgae growth and on the quality of produced biomass.
Ultimately, the CO2-consuming algae can be harvested, dried (possibly using waste heat from the cement plant) before being burned as a fuel inside the plant’s cement kilns. Alternatively, the algal biomass can be processed into 3rd generation biofuels or high added values compounds like anti-oxidants, lipids, proteins.
All the experimental activities of this pilot project are expected to be completed by 2013.