Ésteres alquílicos de ácidos grasos isomerizados como aditivos para el mejoramiento de las propiedades de flujo en frío del biodiesel
Autores
Sierra Cantor, Jonathan Fabian
Director
Tipo de contenido
Trabajo de grado - Maestría
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EspañolFecha de publicación
2016
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Resumen
El biodiesel ha sido propuesto como el principal remplazo del diésel convencional, por lo cual su producción ha incrementado en los últimos años. El principal inconveniente técnico de este es que no presenta un comportamiento adecuado en ambientes fríos. Con el fin de mejorar las propiedades de flujo en frio del biodiesel, la síntesis de ésteres alquílicos de ácidos grasos ramificados mediante catálisis heterogénea ha demostrado buenos resultados mejorando las mismas sin afectar significativamente otras propiedades. Teniendo en cuenta que la reacción de isomerización usando catalizadores heterogéneos ácidos no se puede llevar a cabo sobre ácidos grasos saturados, se propuso la síntesis, caracterización y uso de una zeolita tipo ferrierita impregnada con platino como catalizador heterogéneo sobre ácidos grasos saturados e insaturados para llevar a cabo la reacción de hidroisomerización. El catalizador fue preparado partiendo de una zeolita comercial a través de tratamiento con ácido clorhídrico e intercambio iónico con nitrato de amonio, seguido de impregnación húmeda y reducción de cloruro de tetraaminplatino (II), el cual fue caracterizado por SEM, EDX, TEM, XRF, TPD-NH3, IR, y sortometría de nitrógeno. Debido a los tratamientos aplicados a la ferrierita, nueva mesoporosidad fue creada, facilitando el arribo y adsorción de los ácidos grasos a los sitios activos. La reacción de hidroisomerización fue llevada a cabo a 275 ºC, presión de 1.7 MPa por 6 h. Los productos de la reacción fueron caracterizados mediante RMN. Dichos productos fueron esterificados y sus propiedades de flujo en frio fueron evaluadas, mostrando que presentaban valores de punto de nube y punto de fluidez mejores que los ésteres alquílicos de los ácidos grasos no ramificados. El uso de ésteres isobutílicos de ácidos grasos ramificados como aditivos para el mejoramiento de las propiedades de flujo en frió mostro reducir en punto de nube y punto de fluidez del biodiesel de oleína de palma en 6 (10 a 4°C) y 4 ºC (7 a 3°C) respectivamente.
Abstract. The biodiesel has been proposed as the main replacement of conventional diesel oil, whereby its production has increased in the last years. The main technical problem of this fuel is that doesn´t have an adequate behavior in cold environments. In order to enhance biodiesel cold flow properties, branching of the fatty acids through isomerization reaction over acid heterogeneous catalyst has shown good results improving these properties without affect significantly other properties. Taking into account that isomerization reaction cannot be done on saturated fatty acid, in this work has been proposed the synthesis, characterization and use of a ferrierite zeolite impregnated with platinum as heterogeneous acid catalyst for carry out the hydroisomerization reaction over saturated and unsaturated fatty acid alkyl esters. The catalyst was prepared through activation with chlorhydric acid and ammonium nitrate ionic exchange followed by wet impregnation of Tetraamminplatinum (II) chloride over a commercial ferrierite and characterized by SEM, EDX, TEM, XRF, TPD-NH3, infrared analysis, and nitrogen sorption measurements. Due to the treatments, which that were applied to ferrierite, new mesoporosity was created, facilitating the arrival and adsorption of the fatty acid alkyl esters to active sites Hydroisomerization reaction, was carried out to 285 ºC and 1.7 MPa by 6h. Reaction products were characterized through NMR analysis. They are esterified and their cold flow properties were evaluated, showed that they have better cold flow properties than non-branching fatty acid alkyl esters. The use of isobutyl esters as cold flow properties improvers reached decrease the cloud point and the pour point in 6 (10 a 4°C) and 4 ºC (7 a 3°C) of palm olein biodiesel respectively.
Abstract. The biodiesel has been proposed as the main replacement of conventional diesel oil, whereby its production has increased in the last years. The main technical problem of this fuel is that doesn´t have an adequate behavior in cold environments. In order to enhance biodiesel cold flow properties, branching of the fatty acids through isomerization reaction over acid heterogeneous catalyst has shown good results improving these properties without affect significantly other properties. Taking into account that isomerization reaction cannot be done on saturated fatty acid, in this work has been proposed the synthesis, characterization and use of a ferrierite zeolite impregnated with platinum as heterogeneous acid catalyst for carry out the hydroisomerization reaction over saturated and unsaturated fatty acid alkyl esters. The catalyst was prepared through activation with chlorhydric acid and ammonium nitrate ionic exchange followed by wet impregnation of Tetraamminplatinum (II) chloride over a commercial ferrierite and characterized by SEM, EDX, TEM, XRF, TPD-NH3, infrared analysis, and nitrogen sorption measurements. Due to the treatments, which that were applied to ferrierite, new mesoporosity was created, facilitating the arrival and adsorption of the fatty acid alkyl esters to active sites Hydroisomerization reaction, was carried out to 285 ºC and 1.7 MPa by 6h. Reaction products were characterized through NMR analysis. They are esterified and their cold flow properties were evaluated, showed that they have better cold flow properties than non-branching fatty acid alkyl esters. The use of isobutyl esters as cold flow properties improvers reached decrease the cloud point and the pour point in 6 (10 a 4°C) and 4 ºC (7 a 3°C) of palm olein biodiesel respectively.