41 research outputs found

    Syngas/H2 production from bioethanol in a continuous Chemical-Looping Reforming prototype

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    Chemical-looping reforming (CLR) allows H2 production without CO2 emissions into the atmosphere. The use of a renewable fuel, bioethanol, in an auto-thermal CLR process has the advantage to produce H2 with negative CO2 emissions. This work presents the experimental results obtained in a continuously operating CLR unit (1 kWth) using ethanol as fuel. Two NiO-based oxygen carriers were used during more than 50 h of operation. The influence of variables such as temperature, water-to-fuel and oxygen-to-fuel molar ratios was analysed. Full conversion of ethanol was accomplished and carbon formation was easily avoided. A syngas composed of ≈ 61 vol.% H2, ≈ 32 vol.% CO, ≈ 5 vol.% CO2 and ≈ 2 vol.% CH4 was reached at auto-thermal conditions for both materials. Gas composition was closed to the given by the thermodynamic equilibrium. These results demonstrate the technical viability of H2/syngas production by using bioethanol in an auto-thermal CLR process.This work is partially supported by the Spanish Ministry for Science and Innovation (MICINN project ENE2011-26354) and the European Regional Development Fund (ERDF), and by CTGAS-ER (project OTT20130989). A. Serrano also thanks the Spanish Ministry of Economy and Competitiveness for the F.P.I. fellowshipPeer reviewe

    Supervisión multidistribuida de un secadero solar de madera empleando sensores de bajo coste

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    Se ha llevado a cabo la supervisión multídistribuida de un secadero solar de madera mediante la implementación de sensores de bajo coste. La toma de datos se ha realizado en un secadero experimental de 0,3 m}. La sensórica empleada, consistente básicamente en termopares y módulos SENSIRION™, junto con el modelo psicrométrico definido por ASABE, ha permitido estimar la cantidad de agua extraída de la madera a lo largo del proceso de secado. La supervisión continua del proceso posibilita la implementación de sistemas automáticos de control del secadero mediante la regulación de la velocidad del ventilador y la proporción de aire sujeto a recirculación

    A Genomic Approach for the Identification and Classification of Genes Involved in Cell Wall Formation and its Regulation in Saccharomyces Cerevisiae

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    Using a hierarchical approach, 620 non-essential single-gene yeast deletants generated by EUROFAN I were systematically screened for cell-wall-related phenotypes. By analyzing for altered sensitivity to the presence of Calcofluor white or SDS in the growth medium, altered sensitivity to sonication, or abnormal morphology, 145 (23%) mutants showing at least one cell wall-related phenotype were selected. These were screened further to identify genes potentially involved in either the biosynthesis, remodeling or coupling of cell wall macromolecules or genes involved in the overall regulation of cell wall construction and to eliminate those genes with a more general, pleiotropic effect. Ninety percent of the mutants selected from the primary tests showed additional cell wall-related phenotypes. When extrapolated to the entire yeast genome, these data indicate that over 1200 genes may directly or indirectly affect cell wall formation and its regulation. Twenty-one mutants with altered levels of β1,3-glucan synthase activity and five Calcofluor white-resistant mutants with altered levels of chitin synthase activities were found, indicating that the corresponding genes affect β1,3-glucan or chitin synthesis. By selecting for increased levels of specific cell wall components in the growth medium, we identified 13 genes that are possibly implicated in different steps of cell wall assembly. Furthermore, 14 mutants showed a constitutive activation of the cell wall integrity pathway, suggesting that they participate in the modulation of the pathway either directly acting as signaling components or by triggering the Slt2-dependent compensatory mechanism. In conclusion, our screening approach represents a comprehensive functional analysis on a genomic scale of gene products involved in various aspects of fungal cell wall formation

    Modelización de las condiciones de transporte y conservación prolongada en frutas y hortalizas

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    Este documento se generó a partir de la VI Reunión de la Red Temática FRUTURA de CYTED realizada en la ciudad de Buenos Aires, Argentina del 26 al 30 de Setiembre de 2011. Organizado por el Laboratorio de Calidad y Postcosecha de Frutas y Hortalizas de la E.E.A. Balcarce del INTA, el programa de esta reunión se enmarcó dentro del principal objetivo de la Red, que es el desarrollo de un sistema integral de mejora de la calidad y seguridad de las frutas durante la manipulación, el transporte y la comercialización, mediante nuevas tecnologías de inspección y monitorización

    Assessment of low-cost oxygen carrier in South-western Colombia, and its use in the in-situ gasification Chemical Looping Combustion technology

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    © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In Chemical Looping Combustion (CLC), the Oxygen Carrier (OC) is key element of the process. Most OCs have been developed synthetically, using an active metal oxide combined with an inert material. When solid fuels are used, a loss of OC is expected as it mixes with the ashes generated during the CLC process making the costs elevated. As a result, there is a growing interest in using low-cost OCs based in Mn and Fe. In this research, a by-product derived from manganese ore purification is studied. This material has a high silicon content and it is composed of rhodonite as the main specie and wustite as the minority specie. The material, a Mn mineral from the Nariño department in the Southwest of Colombia, was selected in a previous work based on its good properties such as appropriate crushing strength, an oxygen transport capacity of 3,4 %, and a relatively high reactivity. Here, tests in a batch fluidized bed reactor were carried out with the selected material with CH4, CO, and H2 at 950°C during 50 cycles. A good behaviour was observed with CO and H2, with a moderate attrition, and lifetime of 2950 hours. The material presented a trend towards agglomerating with CH4, and no agglomeration with CO and H2. The possible oxygen uncoupling effect due to the presence of combined oxides of manganese and silicon was also evaluated, but there was no evidence in the 950-1040 ºC interval when the material was oxidized with a 10 vol.% O2. Due to its good performance with CO and H2, the material was evaluated for the in-situ Gasification Chemical Looping Combustion (iG-CLC) technology, using a Chilean reactive coal as fuel at temperatures from 900 °C to 1000 °C. Its good behaviour with H2 and CO makes it a promising OC for iG-CLC technology.This research was conducted with financial support from the Unión Temporal Incombustion (Temporary Joint Working Group) and Colciencias through the Contract of Contingent Recovery RC 0852-2012 and to the collaboration of Instituto de Carboquímica (CSIC) from Zaragoza. Thanks to Ing. Konrad Holscher from Mina Invierno (Chile) for supplying the subbituminous coal batch.Peer reviewe

    Simulación numérica de flujo y transporte de la laguna de Fuente de Piedra en condiciones extremas de densidad variable

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    La laguna de la Fuente de Piedra es un humedal con un alto valor ecológico, fue declarada Reserva Natural y ha sido un de los tres primeros humedales de España en incorporarse al convenio de Ramsar. La laguna (13Km2) se encuentra en una cuenca endorreica (150km2) donde afloran las calcarenitas del Mioceno, que albergan un acuíefor de agua dulce, y el Complejo Caótico Sub-Bético (CCS), que además define el muro del acuífero Mioceno. El CCS del Mioceno inferior-medio es un olistostroma formado por una matriz mago-yesífera de edad triásica y bloques calizos, dolomíticos y margososo de edad Jurásica a Oligocena. Entre el modelo genético de la laguna, el conceptual de su sistema hidrogeológico y el genético-evolutivo de la salmuera existe una relación muy estrecha. La laguna se originó por Karstificación y colapso del material yesífero-salino del CCS. En el sistema hidrogeológico de la laguna se presentan grandes contrastes de densidad: el agua dulce superficial, la salobre y las salumeras someras y profundas. Tradicionalmente, a las salmueras de este sistema se les atribuyó un origen exclusivamente evaporativo y se las ubicó unicamente en la zona de descarga, asociándose a un modelo clásico de cuenca endorreica en clima semiárido.En esta comunicación se propone un nuevo modelo de la laguna apoyado en una modelación axisimétrica del sistema hidrogeológico local de la laguna en régimen cuasi-estacionario de flujo y transporte con densidad variable. Los resultados de la simulación reforzaron las conclusiones de los trabajos realizados previamente que indicaban que el origen de las salmueras no era el resultado exclusivo de la evaporación en la laguna y sugerían la aportación de un sistema profundo kárstico hipersalino desarrollado en el CCS, vinculado con la génesis y evolución de las salmueras de la cuenca. No obstante, los resultados de las simulaciones aquí presentadas modifican parcialmente el patrón de flujo del sistema que sugerían estas conceptualizaciones previas, desestimando las posibles recargas del sistema kárstico desde el acuífero miocenoPostprint (published version

    Reaction kinetics of a NiO-based oxygen carrier with ethanol to be applied in chemical looping processes

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    12 figures, 3 tables.-- Supplementary information available.The use of bio-ethanol in chemical looping combustion (CLC) and reforming (CLR) has the potential to produce energy and/or hydrogen and, as a negative-emissions technology (NET), to remove CO2 from the atmosphere at low cost following the principles of bio-energy with CO2 capture and storage (BECCS). The determination of the rate of the chemical processes involving the fuel conversion with the oxygen carrier is required for the modelling and design of a chemical looping unit. In this work, a kinetic study of ethanol conversion is performed considering a NiO-based material as the oxygen carrier. Combined experiments in TGA and fixed bed were conducted. TGA tests confirmed that the oxygen carrier was reduced by a ethanol-containing gaseous stream at temperatures higher than 773 K. An apparent reaction kinetics for the NiO reduction with ethanol was determined, which might be used in simplified fuel reactor models. However, tests performed in a fixed bed revealed that products derived of the ethanol decomposition, such as CH4, CO, H2 were responsible for NiO reduction, instead of the direct reduction with ethanol. High temperature kinetics of processes involved in ethanol conversion, namely dehydration, dehydrogenation and decomposition, were determined. Both, non-catalytic and Ni-catalytic reactions were of relevance under chemical looping conditions. A reaction pathway was described to be used in detailed fuel reactor models of chemical looping units.This work was supported by Serviço Nacional de Aprendizagem Industrial, SENAI-DR/RN (Ref. 20194247).Peer reviewe

    Assessment of CHADFDM satellite-based input dataset for the groundwater recharge estimation in arid and data scarce regions

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    Aquifer natural recharge estimations are a prerequisite for understanding hydrologic systems and sustainable water resources management. As meteorological data series collection is difficult in arid and semiarid areas, satellite products have recently become an alternative for water resources studies. A daily groundwater recharge estimation in the NW part of the Lake Chad Basin, using a soil–plant-atmosphere model (VisualBALAN), from ground- and satellite-based meteorological input dataset for non-irrigated and irrigated land and for the 2005–2014 period is presented. Average annual values were 284 mm and 30°C for precipitation and temperature in ground-based gauge stations. For the satellite-model-based Lake Chad Basin Flood and Drought Monitor System platform (CHADFDM), average annual precipitation and temperature were 417 mm and 29°C, respectively. Uncertainties derived from satellite data measurement could account for the rainfall difference. The estimated mean annual aquifer recharge was always higher from satellite- than ground-based data, with differences up to 46% for dryland and 23% in irrigated areas. Recharge response to rainfall events was very variable and results were very sensitive to: wilting point, field capacity and curve number for runoff estimation. Obtained results provide plausible recharge values beyond the uncertainty related to data input and modelling approach. This work prevents on the important deviations in recharge estimation from weighted-ensemble satellite-based data, informing in decision making to both stakeholders and policy makers

    Simulación numérica de flujo y transporte de la laguna de Fuente de Piedra en condiciones extremas de densidad variable

    No full text
    La laguna de la Fuente de Piedra es un humedal con un alto valor ecológico, fue declarada Reserva Natural y ha sido un de los tres primeros humedales de España en incorporarse al convenio de Ramsar. La laguna (13Km2) se encuentra en una cuenca endorreica (150km2) donde afloran las calcarenitas del Mioceno, que albergan un acuíefor de agua dulce, y el Complejo Caótico Sub-Bético (CCS), que además define el muro del acuífero Mioceno. El CCS del Mioceno inferior-medio es un olistostroma formado por una matriz mago-yesífera de edad triásica y bloques calizos, dolomíticos y margososo de edad Jurásica a Oligocena. Entre el modelo genético de la laguna, el conceptual de su sistema hidrogeológico y el genético-evolutivo de la salmuera existe una relación muy estrecha. La laguna se originó por Karstificación y colapso del material yesífero-salino del CCS. En el sistema hidrogeológico de la laguna se presentan grandes contrastes de densidad: el agua dulce superficial, la salobre y las salumeras someras y profundas. Tradicionalmente, a las salmueras de este sistema se les atribuyó un origen exclusivamente evaporativo y se las ubicó unicamente en la zona de descarga, asociándose a un modelo clásico de cuenca endorreica en clima semiárido.En esta comunicación se propone un nuevo modelo de la laguna apoyado en una modelación axisimétrica del sistema hidrogeológico local de la laguna en régimen cuasi-estacionario de flujo y transporte con densidad variable. Los resultados de la simulación reforzaron las conclusiones de los trabajos realizados previamente que indicaban que el origen de las salmueras no era el resultado exclusivo de la evaporación en la laguna y sugerían la aportación de un sistema profundo kárstico hipersalino desarrollado en el CCS, vinculado con la génesis y evolución de las salmueras de la cuenca. No obstante, los resultados de las simulaciones aquí presentadas modifican parcialmente el patrón de flujo del sistema que sugerían estas conceptualizaciones previas, desestimando las posibles recargas del sistema kárstico desde el acuífero miocen
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