Production of Fatty Esters from Palm Oil By-Products for use as Phase Change Materials

Palm stearin is the heavy fraction obtained during palm oil refining. It consists mainly of saturated fatty acids and is often an unwanted by-product that reduces the economic efficiency of the processes. Although it is currently used in the manufacture of margarine or industrial vegetable fats, the increase in palm oil production will lead to higher production of palm stearin. The composition, low cost and physicochemical characteristics of palm stearin make it an ideal raw material for obtaining phase change materials for thermal energy storage in solar thermal energy systems. This work explores the esterification of hydrogenated palm stearin (HPS) for obtaining phase change materials with suitable properties for application. The esterification conditions were studied using low and high molecular weight alcohols, like ethanol, butanol and cetyl alcohol, according to Fischer's esterification principles. The esters formation was characterized by attenuated total reflectance infrared spectroscopy. For both HPS and products obtained, melting and solidification temperatures and enthalpies, and heat capacity were determined by DSC according to ASTME793-06(2018) and ASTME1269-11(2018). A crude wax was obtained by esterification of the fatty acids present in palm stearin in all cases. Among the esters produced, the one obtained by using cetyl alcohol, which has a melting temperature of 55.9 °C and an enthalpy of fusion of 257.26 kJ/kg, stands out. This novel PCM is presumed to have an optimal performance for heat storage applications in low temperature solar thermal systems (50°C - 90°C), for hot water supply and space conditioning

Evaluation of sustainability of the production of biofuels of the second generation by means of the application of Analysis Exergy

El acelerado desarrollo en los últimos años de la industria del bioetanol en Colombia y América Latina ha generado como consecuencia un posterior debate sobre sus impactos ambientales, energéticos y el uso de cultivos de uso alimenticio para su producción. Debido a esto, los esfuerzos en el desarrollo de biocombustibles se han enfocado en la búsqueda de nuevas materias primas y el análisis de las tecnologías de producción desde el punto de vista energético y ambiental, que permitan alcanzar el desarrollo sostenible de esta industria. El uso de residuos lignocelulósicos para la producción de biocombustibles, representa una mejor alternativa que los cultivos energéticos tradicionales, ya que no es usado como alimento y en muchos casos representan un problema asociado a su disposición. Así, para asegurar el desarrollo sostenible de los biocombustibles de segunda generación, es necesario confirmar que el consumo energético del proceso global sea menor que la energía obtenida por el uso del biocombustible producido. De esta manera, el análisis exergético representa una gran herramienta que permite evaluar la eficiencia global del proceso, al tiempo que se determinan las etapas que requieren mejoras. En este trabajo, el bagazo de caña ha sido utilizado como materia prima para la producción de biocombustibles de segunda generación. El análisis exergético ha sido usado como herramienta para evaluar la eficiencia y sostenibilidad del proceso de producción de segunda generación. Como caso de estudio, se han evaluado dos esquemas de producción usando como base la utilización de 1200 toneladas diarias de bagazo de caña los cuales fueron simulados usando ASPEN-HYSYS® y software desarrollado por los autores. Con base en los resultados obtenidos han sido identificadas las etapas que requieren mejoras tecnológicas y ha sido analizada la sostenibilidad de las tecnologías analizadas en la industria colombiana.Abstract: The rapid development of the bioethanol industry in Colombia and LatinAmerica sparked a “food versus fuel” debate and further speculation about the industry’s environmental impact. However, lignocellulosic biomass is a great alternative because it utilizes waste resources and, therefore, does not compete with food crops. To ensure the sustainability of the production of second generation biofuels, it is necessary to confirm that the energy content of biofuels produced from lignocellulosic biomass is significantly greater than the energy consumed in the process. Exergy analysis serves as a unified and effective tool to evaluate the global process efficiency. As bagasse does not jeopardize the food supply, this paper analyzes the integration of sugarcane bagasse as a raw material for second generation biofuels production. Exergy analysis evaluates the performance of sugarcane bagasse and its sustainability in the bioethanol production process. This case study implements a design and process integration to compare two biorefinery topologies using the typical daily amount of residual biomass produced by the sugar industry (1,200 tonnes). Based on results, the stages with most need of improvement were identified and the sustainability of technologies in Colombia was analyzed. This study was executed by the use of the ASPEN-HYSYS® program and other software developed by the authors

El método estocástico de aproximaciones externas para minimización de los costos de control de contaminación del aire

IP 1241-05-11483ARTICULO(S) EN REVISTA: Solucion numerica del problema decontrol de contaminacion del aire / Fedossova A.,;Kafarov V., Mahecha Bohorquez D.P. -- En: Revista colombiana decomputacion. -- Vol. 4, no. 2 (dic. 2003); p.;21-28. -- ISSN 16572831