Publicação
Produção de biodiesel pelas microalgas Scenedesmus Obliquus e Nannochloropsis sp.: optimização dos processos de pré-tratamento e conversão
| Resumo: | In the present study the suitability of microalgae Scenedesmus obliquus and Nannochloropsis sp . feedstock for biodiesel production was evaluated. Some pre-treatments for cell rupture of microalgal dry biomass were studied, in particular mechanical (coffee grinder and bead mill), in order to extract the lipid fraction. The results showed that Nannochloropsis sp. and Scenedesmus obliquus had an aproximate lipid content of 35 g/100g ps and 17 g/100g ps, respectively, and that there was no need for a particular pre-treatment for the Scenedesmus obliquus while for Nannochloropsis sp. it was necessary a relatively aggressive grinding. The lipid fraction of Scenedesmus obliquus had an acid value of 8 mgKOH/g and a fatty acid composition dominated by palmitic acid (23%), oleic (37%) and linoleic (14%). For Nannochloropsis sp., the extracted lipids had an acid value of 82 mg KOH/g and the main fatty acids were palmitic acid (33%), palmitoleic (36% ) and oleic (20%). In both cases, it was determined that the lipidic fractions had an unsaponifiable matter content above 95%. The direct transesterification process was also studied for both microalgae and, due to the high acid value, the influence of the volume of methanol, the acid catalyst concentration and reaction time for the Scenedesmus obliquus was evaluated in order to produce FAME. The results showed that it is possible to produce approximately 40 g/100g ps and 18g/100g ps fatty acid methyl esters from Nannochloropsis sp. and the Scenedesmus obliquus, respectively. In order to evaluate the potential for recovery of residual biomass the total lipids, total sugars, protein and minerals content was determined. The results for the Scenedesmus obliquus were 32 g/100g ps, 34 g/100g ps, 18 g/100g ps and 6g/100g ps, respectively, and for the Nannochloropsis sp. 51 g/100g ps , 18 g/100g ps, 8 g/100g ps and 7 g/100g ps, respectively. |
|---|---|
| Autores principais: | Marques, Ricardo Jorge Falcão |
| Assunto: | Scenedesmus obliquus Nannochloropsis sp. Rutura celular Trasesterificação direta Biodiesel Teses de mestrado - 2013 |
| Ano: | 2013 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | In the present study the suitability of microalgae Scenedesmus obliquus and Nannochloropsis sp . feedstock for biodiesel production was evaluated. Some pre-treatments for cell rupture of microalgal dry biomass were studied, in particular mechanical (coffee grinder and bead mill), in order to extract the lipid fraction. The results showed that Nannochloropsis sp. and Scenedesmus obliquus had an aproximate lipid content of 35 g/100g ps and 17 g/100g ps, respectively, and that there was no need for a particular pre-treatment for the Scenedesmus obliquus while for Nannochloropsis sp. it was necessary a relatively aggressive grinding. The lipid fraction of Scenedesmus obliquus had an acid value of 8 mgKOH/g and a fatty acid composition dominated by palmitic acid (23%), oleic (37%) and linoleic (14%). For Nannochloropsis sp., the extracted lipids had an acid value of 82 mg KOH/g and the main fatty acids were palmitic acid (33%), palmitoleic (36% ) and oleic (20%). In both cases, it was determined that the lipidic fractions had an unsaponifiable matter content above 95%. The direct transesterification process was also studied for both microalgae and, due to the high acid value, the influence of the volume of methanol, the acid catalyst concentration and reaction time for the Scenedesmus obliquus was evaluated in order to produce FAME. The results showed that it is possible to produce approximately 40 g/100g ps and 18g/100g ps fatty acid methyl esters from Nannochloropsis sp. and the Scenedesmus obliquus, respectively. In order to evaluate the potential for recovery of residual biomass the total lipids, total sugars, protein and minerals content was determined. The results for the Scenedesmus obliquus were 32 g/100g ps, 34 g/100g ps, 18 g/100g ps and 6g/100g ps, respectively, and for the Nannochloropsis sp. 51 g/100g ps , 18 g/100g ps, 8 g/100g ps and 7 g/100g ps, respectively. |
|---|