Innovative Plant for the Production of Microalgaes

Abstract

It is strongly felt the need to replace fossil fuels with other renewable and more compatible with the environment. The spinneret of algal crops is producing different solutions ("open ponds", tubular, bioreactors in greenhouses, etc.). The aim is to obtain concentrations of dry substance such as to justify the high costs of extraction. Another limitation suffered by the actual plants, derives from the choice to move the algal mass (process characterized by a high energy consumption), with actions necessary to keep it in suspension as well as to move it, to exchange its positioning in order to bring it to be conditioned by the light (exhausting its effectiveness after the first 0.2-0.3 m of algal mass depth, or even less if thicker and when it would need more light for its exponential growth). In particular, it is not possible to bring a specific radiation spectrum, in a pervasive and deep way, with a drastic cost reduction for the mechanical movement of the culture medium. A limitation derives also from the possibility of biological and chemical contamination from the environment, because the algal mass is in a large contact with the environment itself (e.g. the "open ponds" situations) and it is heavily exposed to the prevalent thermal cycles (often not suitable to the processes of growth) inside it. Some problems are often encountered even in the phase of collection and selection of the algal mass to be forwarded to the following processes, that proceeds through the massive processing of large volumes (by filtration and concentration) that, due to previous limitations (contamination and uncertain conditions of growth), remain at low concentrations. The purpose of this article is to present the PBRC (Photo Bio Reactor Continuous) plant, subject of an Italian patent, for the cultivation of microalgae, from which to extract an oleic fraction, which can be destined for production of biofuels, and a protein fraction, which can be destined for use in the chemical, agri-food, pharmaceutical and cosmetic sectors.