Physical-energy characterization of microalgae Scenedesmus and experimental pellets

The constant increase in biofuel consumption has originated a wide variety concerning the use of raw materials for biofuel manufacture. Currently, ISO 17225 norm establishes a set of kinds and specifications for the use of solid biofuels-woody, herbaceous, fruit and aquatic biomass, along with their combinations or mixtures-. One of the non-woody kinds of pellets in this norm is aquatic biomass, among which the cultivation of microalgae stands out. Even though the main use of microalgae is not for energy purposes, its potential is significant due to their high photosynthesis efficiency, fast growth rate, efficient CO2 fixation and no competition with arable land. The present research work offers an additional alternative for microalgae use, that is, the densification of the waste obtained after microalgae conversion to biodiesel and biogas. Thus, an analysis of the energy viability of wastes from Scenedesmus microalgae was carried out. Satisfactory results would revalue this waste, obtaining an additional biofuel. The initial characterization showed poor outcomes concerning nitrogen, sulphur and ash content -well above most biomass fuels-. Nevertheless, physical characterization of the pellets manufactured was satisfactory. After a preliminary drying, the waste showed good properties for densification, which is a positive circumstance for the intended purposes, such as energy, animal feeding, etc.