Thesis EXTRACCIÓN DE TRIGLICÉRIDOS DESDE NANNOCHLOROPSIS SP. USANDO CO2 SUPERCRÍTICO COMO SOLVENTE
Date
2017
Authors
GÓMEZ LÓPEZ, CRISTÓBAL JOSÉ
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Abstract
Las primeras generaciones de biocombustibles tienen como fuente de materia prima, las semillas oleaginosas y otras fuentes vegetales; esto representa un dilema considerando que es una fuente de alimento. Es por esto que se buscan fuentes alternativas de triglicéridos para producir biodiesel; una de ellas son las microalgas, que tienen un alto crecimiento y desarrollo científico. Dentro de las microalgas se destaca por su alto contenido en ácidos grasos, la Nannochloropsis sp.El objetivo de este trabajo fue extraer triglicéridos de esta microalgas utilizando CO2 supercrítico en condiciones típicas de extracción en semillas oleaginosas (40 – 60 °C y 300 – 450 Bar). Además, se propuso modelar la transferencia de materia con modelo de fuerza impulsora lineal (Modelo LDF) para simular las curvas acumulativas, y así obtener los distintos parámetros de transferencia de materia.El sustrato utilizado (Nannochloropsis sp.), fue pre-tratado en forma de comprimidos con el objetivo de evitar la compactación del lecho, que producía canalización del flujo de CO2 y pobre rendimiento de extracción. Se caracterizó físicamente el sustrato (contenido de aceite: 7,6 %, porosidad de lecho: 4,9 %), y se realizaron las extracciones de triglicéridos en un extractor de 93,23 cm3 usando una velocidad superficial de 0,4 mm/s. Finalmente, con los datos experimentales se realiza la posterior modelación mediante software MATLAB.Dentro de los resultados observados, la solubilidad operacional se comportó como reportan fuentes bibliográficas: en procesos con presión bajo el punto de cross-over (punto donde se cruzan las curvas de solubilidad vs presión), un aumento de temperatura afecta negativamente la solubilidad; mientras que sobre este punto afecta positivamente. Además, la solubilidad operacional experimental es menor que su valor termodinámico (un 11,12% para 300 bar y un 4,79% para 450 bar), esto se debe principalmente, debido a que, bajo estas condiciones predomina la transferencia de materia extra-partícula, extrayéndose en gran mayoría, el triglicérido que solubiliza de forma natural inicialmente con el CO2 supercrítico. Esto se justifica con el rendimiento de extracción neto para cada una de las condiciones de operación (57,33% de rendimiento neto para 300 bar y 37 % para 450 bar), y con los valores de los coeficientes globales, externos e internos de transferencia de materia obtenidos para cada caso.Al contrastar el modelo y los datos experimentales, el Modelo de Fuerza Impulsora Lineal (LDF), es adecuado para modelar extracciones de Nannochloropsis sp. Sin embargo, es importante conocer el punto de cross-over para determinar en dónde se comienzan a apreciar diferencias más significativas en los parámetros de ajuste.
Biodiesel´s production needs of triglycerides for its production. The first generations of biofuels took the oily seeds as a source of triglycerides; this represented a quandary thinking that this raw material is a food source. That's why they look for alternative sources of greasy acids; one of them, which has a high growth and development, it is the micro seaweed, Nannochloropsis sp standing out, for its suppressed high place of greasy acids.The target of this work was to extract triglycerides from this one micro seaweed using supercritical CO2 in typical extraction conditions of operation in oily seeds (40 – 60 °C and 300 – 450 Bar). Also, he proposed to shape the matter transference with the hypothesis of linear driving force (Model LDF) to simulate the accumulative curves, and this way to obtain the different parameters of mass transfer.The substratum (Nannochloropsis sp), it was a pre-agreement in pellets, with the goal to avoid the compression of the bed, which was producing canalization of CO2 – SC´s flow and poor extraction yield. There was characterized physically the substratum (Oil content: 7.601%, Bed porosity: 4.92%), and triglyceride’s extraction were realized in an extractor of 93.23 cm3 using a superficial velocity in the order of 0.4 mm/s, for the later modeling using MATLAB by finite differences methodology.Inside the observed results, the operational solubility behaved as bibliographical sources bring: in processes with pressure under the cross-over point (pressure where the solubility curves cross), an increase in temperature adversely affects the solubility; while on this point affects positively. Also, the experimental operational solubility is less than its thermodynamic value (11.88 % average for 300 bar and 4.79 % for 450 bar), this owes principally because, under these conditions it predominates over the extra-particle mass transfer, extracting in majority, the triglyceride that solubilize in initial natural form with the supercritical CO2. This is justified by the clear extraction yield for each conditions of operation (57.33 % of average clear yield for 300 bar and 37 % for 450 bar), and the values of the global, external and internal coefficients of mass transfer, obtained for every case.Additionally it appreciated for this work, the pretreatment wasn´t sufficient to achieve a interconnected pores network, justifying itself this way, the predominance of the external mass transfer.On having confirmed the model and the experimental information, the Linear Drivin Force Model (LDF), it is adapted to extractions of Nannochloropsis sp triglycerides, to conditions of extraction used usually in the industry. Nevertheless, it is important to know the cross-over point to determine where they begin to appreciate more significant differences in the adjustment parameters.
Biodiesel´s production needs of triglycerides for its production. The first generations of biofuels took the oily seeds as a source of triglycerides; this represented a quandary thinking that this raw material is a food source. That's why they look for alternative sources of greasy acids; one of them, which has a high growth and development, it is the micro seaweed, Nannochloropsis sp standing out, for its suppressed high place of greasy acids.The target of this work was to extract triglycerides from this one micro seaweed using supercritical CO2 in typical extraction conditions of operation in oily seeds (40 – 60 °C and 300 – 450 Bar). Also, he proposed to shape the matter transference with the hypothesis of linear driving force (Model LDF) to simulate the accumulative curves, and this way to obtain the different parameters of mass transfer.The substratum (Nannochloropsis sp), it was a pre-agreement in pellets, with the goal to avoid the compression of the bed, which was producing canalization of CO2 – SC´s flow and poor extraction yield. There was characterized physically the substratum (Oil content: 7.601%, Bed porosity: 4.92%), and triglyceride’s extraction were realized in an extractor of 93.23 cm3 using a superficial velocity in the order of 0.4 mm/s, for the later modeling using MATLAB by finite differences methodology.Inside the observed results, the operational solubility behaved as bibliographical sources bring: in processes with pressure under the cross-over point (pressure where the solubility curves cross), an increase in temperature adversely affects the solubility; while on this point affects positively. Also, the experimental operational solubility is less than its thermodynamic value (11.88 % average for 300 bar and 4.79 % for 450 bar), this owes principally because, under these conditions it predominates over the extra-particle mass transfer, extracting in majority, the triglyceride that solubilize in initial natural form with the supercritical CO2. This is justified by the clear extraction yield for each conditions of operation (57.33 % of average clear yield for 300 bar and 37 % for 450 bar), and the values of the global, external and internal coefficients of mass transfer, obtained for every case.Additionally it appreciated for this work, the pretreatment wasn´t sufficient to achieve a interconnected pores network, justifying itself this way, the predominance of the external mass transfer.On having confirmed the model and the experimental information, the Linear Drivin Force Model (LDF), it is adapted to extractions of Nannochloropsis sp triglycerides, to conditions of extraction used usually in the industry. Nevertheless, it is important to know the cross-over point to determine where they begin to appreciate more significant differences in the adjustment parameters.
Description
Catalogado desde la version PDF de la tesis.
Keywords
BIOCOMBUSTIBLES , MICROALGAS , PRODUCCION DE BIODIESEL
