The goal was achieved, thanks to an intense activity of multidisciplinary research led by Eni and involving the Eni Research Center for Renewable Energy and the Environment in Novara, the Eni Upstream Research Center in Sandonato, the Upstream and Downstream business areas and the Energy Solutions Department for ten years. The pilot plant on which production trials are being conducted was built a Ragusa, where the carbon dioxide extracted from the wells managed by Enimed together with the hydrocarbons is separated and sent to Eni's Renewable Energy Plant and distributed in fourteen large transparent cylinders made by Sun Algae Technology, an Austrian startup now bought by an Italian group.
In these five-metre-high fiberglass cylinders, swirls a green liquid made up of countless microscopic algae suspended in salt water. To make the environment even more sci-fi the cylinders are in the shade but they shine in a very strange way. Looking on the roof we discover the origin of those strange lights: large solar concentrators which rotate slowly chasing the Sun. Each of these concentrators is made up of thousands of brilliant Fresnel lenses which concentrate the sunlight on as many optical fibers which are then conveyed into the cylinders below, illuminating the algae.
Hence the name of photobioreactors. With the sunlight focused right on them and fossil carbon dioxide bubbling under them, the algae have what it takes to grow and become ever more numerous. Once extracted from the water, the seaweed is dried into a flour rich in lipids, from which an oil is extracted that can be sent to biorefineries of Eni instead of the current diet consisting of palm oil. Meanwhile, the water is separated, purified and fed back into the photobioreactors where the next generation of microalgae will grow.
A look into the future
The Ragusa pilot plant is able to capture and reuse 80 tons/year of carbon dioxide allowing the production of 40 tons/year of algal flour, which in turn allows the production of 20 tons of bio-oil thanks to sunlight captured by 320 square meters of solar concentrators. But this is only the beginning: based on the data obtained from this first pilot plant - already in operation since September 2017 - Eni plans to build a plant capable of treating up to 1.500 tons of CO2 per year; always within the Enimed plant in Ragusa.
The result is the result of the skills gained in the treatment and cultivation of microalgae, in the development of innovative solar technologies, in the refining processes of petroleum products, in the formulation of green chemistry products and in the technologies for the construction of biorefineries. In summary: the fossil carbon dioxide produced by the oil plants is eliminated and – thanks to Eni's biorefineries – green fuel using sunlight and creating a virtuous cycle between conventional oil facilities and advanced refining facilities. Finally, we recall that a third generation bio-oil is produced which it is transformed into biodiesel not in competition with agricultural crops for food use.
Da Eniday.
Nice, but…..with the current efficiency, only 1 plant therefore produces 20m3 (about 20.000 liters) of biofuel for Diesel cycle engines which, if used by 1 TIR-truck, are needed for an autonomy of about 100.000 km (average consumption optimistic of 5 km/lt). Practically the average distance of 4-8 months of just 1 vehicle. Good experimentation but more is needed. Transformation to natural gas with electric hybridization of diesel engines are the technological elements to be pursued for efficiency and rapid reduction of pollutants on medium/long distances (Mercedes-Benz docet).