Transesterificação supercrítica de óleo vegetal e etanol: efeito da temperatura e do tempo de residência na formação de fases e no teor de água

Supercritical transesterification has emerged as a readily available alternative for biodiesel production since no catalyst is required, thereby generating fewer waste products. In this research, the supercritical transesterification of refined vegetable oil and aqueous ethanol was carried out at temperatures 400 to 480 °C and a 12:1 ethanol to oil molar ratio, to assess the effect of temperature and residence time in the formation of a homogeneous phase, effluent appearance and increased water content derived from glycerol etherification. The results showed that water was produced at temperatures higher than 400 °C, as expected from the occurrence of glycerol etherification, and that prolonged times resulted in gas and soot formation, indicating esters decomposition. Through water mass balances, it was possible to identify the set of operation conditions in which the water formed from glycerol etherification matched with the maximum expected according to the proposed reaction scheme.La transesterificación supercrítica se ha propuesto como una alternativa para la producción de biodiesel ya que no requiere catalizador, de esta manera se generan menos residuos. En esta investigación, la transesterificación supercrítica de aceite vegetal refinado y etanol acuoso se llevó a cabo a temperaturas en el rango 400 a 480 °C y relación molar etanol a aceite de 12:1, para evaluar el efecto de la temperatura y el tiempo de residencia en la formación de una fase homogénea, apariencia del efluente e incremento del contenido de agua resultado de las reacciones de eterificación del glicerol. Los resultados mostraron que se produjo agua a temperaturas mayores a 400°C, atribuida a la eterificación del glicerol, y que tiempos de residencia prolongados resultaron en formación de gas y hollín, indicativo de reacciones de descomposición de esteres. A través de balances de masa, fue posible identificar el conjunto de condiciones de operación a las cuales el agua formada por la eterificación del glicerol coincide con el valor máximo esperado de acuerdo con el esquema de reacción propuesto.A transesterificação supercrítica foi proposta como uma alternativa para a produção de biodiesel porque não requer catalisador e, dessa forma, gera menos resíduos. Nesta pesquisa, a transesterificação supercrítica de aceite vegetal refinado e etanol acuoso foi conduzida a temperaturas entre 400 e 480 °C e uma relação molar de etanol e aceite de 12: 1, para avaliar o efeito da temperatura e do tempo de residência na formação de uma fase homogênea, apariência do efluente e aumento do conteúdo de água resultante das reações de eterificação do glicerol. Os resultados mostraram que se produziu água a temperaturas maiores que 400°C, atribuída à eterificação do glicerol, e que os tempos de residência prolongados resultaram na formação de gás e hollín, indicativo de reações de decomposição de ésteres. Por meio de balanças de massa, foi possível identificar o conjunto de condições de operação em que a água formada pela eterificação do glicerol coincide com o valor máximo esperado de acordo com o esquema de reação proposto

Selection of soybean pods by the stink bugs, Nezara viridula and Piezodorus guildinii

Different biological parameters of the stink bugs, Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae), are affected by the developmental stage of the soybean ( Glycine max Merrill) pods they feed on. These effects of the soybean on the stink bugs could represent a selection pressure leading to the ability of these species to discriminate the phenological stage of soybean pods, and, therefore, to exhibit feeding preferences. We designed three studies: (1) Distant detection of soybean pods through an olfactometer; (2) Free choice tests to evaluate preferences for soybean pods of different developmental stages; (3) No choice tests to study effects of soybean pod development on feeding time and number of probes. Stink bugs showed no differential response to olfactometer arms with or without soybean pods, suggesting an inability to detect soybean volatiles. Free choice tests showed no species effects on pods selection, but significant differences among fifth instar nymphs, adult male, and adult females. Fifth instar nymphs fed more frequently on soybean pods of advanced development stages compared to female adults, despite previous evidence showing poor development of stink bugs fed pods of the same stage. No choice tests showed significant effects of stink bug species, stink bug stage and sex, and soybean pod phenology. N. viridula expressed shorter feeding times and higher numbers of probes than P. guildinii. The highest numbers of probes of both species were observed when they were fed soybean pods in early phenological stages. When placed in direct contact with food, fifth instar nymphs prefered to feed on more developed pods, despite these pods being suboptimal food ítems. These results suggest that for the ecological time framework of soybean-stink bugs coexistence, around thirty-five years in Argentina, the selection pressure was not enough for stink bugs to evolve food preferences that match their performance on soybean pods of different development stages.EEA ManfrediFil: Molina, Gonzalo Alberto Roman. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Trumper, Eduardo Victor. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; Argentin

Análisis de la viabilidad técnica y económica de una planta de gasificación de biomasa residual agrícola para suministro de una central de cogeneración en la comarca del Segrià

Treballs Finals del Màster d’Energies Renovables i Sostenibilitat Energètica, Facultat de Física, Universitat de Barcelona, Curs: 2013-2014, Tutor: Miguel Villarrubia LópezEl presente estudio pretende realizar un análisis de viabilidad técnica y económica para la implantación de una planta de cogeneración a partir de la gasificación de biomasa residual agrícola en la comarca del Segrià. Esta tecnología permite revalorizar energéticamente los residuos agrícolas proporcionando un gas de síntesis apto para generar energía eléctrica y térmica. Además la actividad de la planta de cogeneración contribuye a mejorar la sostenibilidad del territorio a la vez que se genera empleo y actividad económica. Para determinar la viabilidad técnica del proyecto se realiza un análisis de la disponibilidad de biomasa en la comarca y se evalúa la capacidad del territorio para abastecer el consumo nominal de la planta de cogeneración. Para determinar la viabilidad económica del proyecto se han analizado diversos indicadores que permiten aceptar o rechazar el proyecto considerando los costes y beneficios generados por éste durante toda su vida útil. Para realizar el análisis económico se ha elaborado un plan logístico que permita conocer con exactitud los costes asociados al tratamiento de la biomasa residual agrícola. Otros costes asociados a las operaciones de la planta de cogeneración se han determinado mediante datos técnicos facilitados por el fabricante. Con la finalidad de conocer los ingresos de la actividad mediante la venta de su producción energética se ha desarrollado el balance energético del proceso. Posteriormente, mediante la aplicación del RD 413/2014, que regula la remuneración a las energías renovables, se ha estudiado la viabilidad de distintos futuros escenarios para la central energética..

Sistema de cámara térmica para bomberos

[ES] A lo largo de este trabajo final de grado se quiere desarrollar un sistema de cámara térmica para bomberos, centrándose en la compatibilidad del microcontrolador ESP32 con la cámara térmica Flir Lepton y una pantalla de reducido tamaño. El objetivo principal es obtener en tiempo real una imagen térmica que el usuario pueda visualizar sin necesidad de tener las manos ocupadas, permitiendo que el bombero puede desarrollar su labor de forma más independiente. Los elementos elegidos para formar parte del sistema permiten que el mismo se pueda utilizar de forma autónoma acompañándolo de una batería. Además, en posteriores desarrollos, se pretende poder aprovechar las características multi-núcleo y la conectividad inalámbrica wifi y bluetooth para transmitir en tiempo real la imagen obtenida.[EN] Throughout this final degree project, we want to develop a thermal camera system for firefighters, focusing on the compatibility of the ESP32 microcontroller with the Flir Lepton thermal camera and a small size screen. The main objective is to obtain in real time a thermal image that the user can visualize without having their hands occupied, allowing the firefighter to develop his work more independently. The elements chosen to be part of the system allow it to be used autonomously accompanied by a battery. In addition, in subsequent developments, it is intended to take advantage of the multi-core features and wireless connectivity wifi and bluetooth to transmit in real time the imageIbáñez Molina, V. (2019). Sistema de cámara térmica para bomberos. http://hdl.handle.net/10251/124659TFG

Impact of external industrial sources on the regional and local SO2 and O3 levels of the Mexico megacity

The air quality of megacities can be influenced by external emission sources on both global and regional scales. At the same time their outflow emissions can exert an impact to the surrounding environment. The present study evaluates an SO2 peak observed on 24 March 2006 at the suburban supersite T1 and at ambient air quality monitoring stations located in the northern region of the Mexico City Metropolitan Area (MCMA) during the Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign. We found that this peak could be related to an important episodic emission event coming from Tizayuca region, northeast of the MCMA. Back-trajectory analyses suggest that the emission event started in the early morning at 04:00 LST and lasted for about 9 h. The estimated emission rate is about 2 kg s[superscript −1]. To the best of our knowledge, sulfur dioxide emissions from the Tizayuca region have not been considered in previous studies. This finding suggests the possibility of "overlooked" emission sources in this region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the state of Hidalgo and in the State of Mexico. It was found that they can contribute to the SO2 levels in the northeast (NE) region of the basin (about 42%), at the suburban supersite T1 (41%) and that at some monitoring stations their contribution can be even higher than the contribution from the Tula Industrial Complex (TIC). The contribution of the Tula Industrial Complex to regional ozone levels is estimated. The model suggests low contribution to the MCMA (1 to 4 ppb) and slightly higher contribution at the suburban T1 (6 ppb) and rural T2 (5 ppb) supersites. However, the contribution could be as high as 10 ppb in the upper northwest region of the basin and in the southwest and south-southeast regions of the state of Hidalgo. In addition, the results indicated that the ozone plume could also be transported to northwest Tlaxcala, eastern Hidalgo, and farther northeast of the State of Mexico, but with rather low values. A first estimate of the potential contribution from flaring activities to regional ozone levels is presented. Results suggest that up to 30% of the total regional ozone from TIC could be related to flaring activities. Finally, the influence on SO2 levels from technological changes in the existing refinery is briefly discussed. These changes are due to the upcoming construction of a new refinery in Tula. The combination of emission reductions in the power plant, the refinery and in local sources in the MCMA could result in higher reductions on the average SO[subscript 2] concentration. Reductions in external sources tend to affect more the northern part of the basin (−16 to −46%), while reductions of urban sources in the megacity tend to diminish SO[subscript 2] levels substantially in the central, southwest, and southeast regions (−31 to −50%).United States. Dept. of Energy (Atmospheric System Research Program, Contract DE-AC06-76RLO 1830)National Science Foundation (U.S.) (NSF award AGS-1135141)Consejo Nacional de Ciencia y Tecnología (Mexico