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Browsing by Author "Morais, Ana Filipa Garcia de"

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  • Estudos de transesterificação de óleos produzidos a partir de Chlorella protothecoides por via heterotrófica
    Publication . Morais, Ana Filipa Garcia de; Reis, Alberto José Delgado dos; Justino, Ana Cristina Ramos de Oliveira
    This work aimed to study the feasibility of biodiesel production from the heterotrophic Chlorella protothecoides microalga. Firstly, microalgae biomass production via fermentation was initiated and monitored. The need of a previous treatment for cell rupture of the dried biomass was evaluated through a mechanical disruption with a bead mill, allowing a saponifiable lipid fraction’s extraction of 50.15±1.07g/100g dw biomass. The lipid fraction showed an acid value of 3.96±0.12mgKOH/g, an iodine value of 85.22 gI2/100g and a fatty acids profile dominated by the presence of oleic (57.06%), linoleic (22.61%) and palmitic (14.47%) acids. The saponifiable matter content, determined in the extracted lipid fraction and directly in the biomass, was 96%. Other quality parameters, such as saponification value (189.87 mgKOH/g), cetane number (54.46) and CFPP (-9.07ºC), were also assessed. The obtained results are in accordance with the EN 14214 quality requirements, enabling the production of good quality biodiesel from the studied microalga. To complete the characterization of microalgae’s composition the content of total lipids (58.34g/100g dw), carbohydrates (17.47±4.06g/100g dw), protein (6.45g/100g dw) and ash (6.92±0.52g/100g dw) contents were also determined. For the biodiesel conversion, the microalgal biomass was put through a direct transesterification. The influence of several parameters in the amount of esters converted has been evaluated. The process has revealed itself effective for a 18h reaction time, with 95% of the saponifiable matter being converted. The process showed to be sensitive to the presence of moisture in the biomass and also to the reaction temperature. In a preliminary economic and energy analysis, at lab scale, the soxhlet extraction followed by an alkaline transesterification showed to be the most efficient process (0.139). The direct transesterification process proved itself to be a better economic option (11.53€/kg biodiesel) although still far from the economic feasibility.
    2015Master thesis Open access Show more