Biorefinaria de pinhão-manso (Jatropha curcas L.): armazenamento, extração de óleo e produção sustentável de biodiesel com etanol

• Autor(a) principal: Santos, Silmara Bispo dos
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/701
• topic: Qualidade grãos; Qualidade de óleo; Cadeia produtiva; Co-produtos; Grain quality; Oil quality; Supply chain; Co-products; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

Biorefinery is a conceptual structure in which different processes of transformation are put side by side, so that the product of one process becomes the raw material of the next process. Biodiesel, a renewable fuel obtained by transesterification of vegetable oils or animal fat has been inserted in the energetic matrix of Brazil gradually. The raw material diversification for biodiesel production with the use of crops with high oil yield like Jatropha, and the use of by-products by applying a biorefinery concept can contribute for reducing costs and meet demand for this fuel oil. Considering Jatropha potential as raw material for biodiesel production, this study aimed to contribute for structuring production chain of biodiesel from Jatropha and reduction of production costs, using the biorefinery concept. For this purpose, this work was organized in six articles with the following specific objectives: Article I - Evaluate the accumulation of dry matter and oil in the Jatropha seeds and quality of oil extracted at different stages of fruit ripening. Article II Get hygroscopic equilibrium data of Jatropha oilseeds and evaluate the thermodynamic parameters of the desorption process. Article III evaluate the effect of storage conditions on the quality of jatropha oilseeds, oil and ethylic biodiesel of jatropha. Article IV - Evaluate the temperature effect, particles size, grains water content, and time on the yield about the extracting process of oil from Jatropha, using central composite rotatable design and response surface methodology to identify the optimal conditions. Article V Evaluate the temperature effect, water content, and particles size on yield and on the kinetic and thermodynamic parameters of the extracting process of oil from Jatropha. Article VI Evaluate the energetic potential of co-products from chain of biodiesel production from Jatropha. In study to evaluate the dry matter and oil accumulation from Jatropha oilseeds at different maturation stages, it was concluded that the harvest of brown-yellow and brown fruits provided higher yields in dry matter and oil of seeds. The brown-yellow ruits presented higher oil yield and dry matter, lower acid value, so its represent the more suitable ripening stage for harvesting fruits and seeds for industrial uses. In the post-harvest sector, equilibrium moisture knowledge is essential for drying, aeration, and grains storage. The modified Henderson's model was considered adequate to represent and estimate the equilibrium moisture in desorption process of Jatropha oilseeds. Equilibrium moisture content of Jatropha oilseeds is directly proportional to relative humidity and for the same value of relative humidity, decreases as temperature increases. Enthalpy and entropy change were found to be positive, indicating that the desorption of Jatropha oilseeds is endothermic and irreversible process. A negative change of free energy was obtained, indicating the spontaneous nature of the desorption process in Jatropha oilseeds for conditions evaluated. During storage, changes in Jatropha oilseeds quality were lower for 15 °C temperature. In the crude oil stored in glass containers sealed and in the absence of light, changes in acid value, saponification value, viscosity and relative density were lower when compared to the oil held within the grains during storage. Storage of dry oil in sealed container in the absence of light and oxygen can contribute more effectively to maintain the quality of this product compared to the maintenance of the oil within the grains. The temperature influenced only the acidity value and kinematic viscosity of ethylic biodiesel of Jatropha during the storage and the changes in these parameters were more pronounced for the conditions of 25 ° C and at room temperature (22.9 ± 0.6 °C). The time was crucial to quality loss of ethylic biodiesel of Jatropha, causing significant changes in all evaluated parameters. Controlled temperature use at 15°C was not effective in controlling biodiesel degradation and maintenance of its quality during storage for extended periods, necessitating antioxidants use to slow the deteriorating processes and keep it within the standards quality required by the NPA (National Petroleum Agency). In the extracting process, the factors temperature, grains moisture content, particles size, and time influenced significantly the extracted oil yield. For the evaluated conditions, the yield of extracted oil increased with increasing temperature and with the decrease of grains moisture content and particles size. The conditions to maximize the extracted oil yield with ethanol were: temperature of 68 °C; moisture content of 0 %, average particle size of 0.5 mm or less, and time of 120 minutes. Under these conditions, the yield of extracted oil was estimated to be 73.8 % of oil in the samples. In the kinetic study of the extraction process, it was concluded that for all evaluated conditions the yield of oil in liquid phase close to equilibrium can be obtained in approximately 20 minutes. After this time, the exchange of saturated solvent for pure solvent is necessary to continue the process and retrieval of oil remaining in the particles, thereby increasing the final yield and minimizing the process costs. Enthalpy and entropy change was found to be positive, indicating the endothermic and irreversible nature of extraction process. The obtained values from the change of free energy indicated that the extraction process using ethanol as solvent is spontaneous and thermodynamically favorable for 0 % of moisture content and the spontaneity was favored with an increase in temperature. Coproducts of the biodiesel production chain from Jatropha under shells, cake, and bran form have energetic characteristics that make possible its use for energy production for used in different processes. Shells can be used for direct combustion and heat generation for processes such as drying the Jatropha oilseeds. The cake and bran have high heating value similar to eucalyptus wood and sugar cane bagasse, widely used in systems of cogeneration power in the sugar and alcohol industry. Thus, they can be used raw or compressed to heat generation for processes such as drying of broken grains in the processing industry, oil extraction and refining, transesterification and solvent recovery, biodiesel distillation among others.