Examinando por Materia "Carbon dioxide"
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Ítem A Comparative Assessment of Emerging Solvents and Adsorbents for Mitigating CO2 Emissions From the Industrial Sector by Using Molecular Modeling Tools(Frontiers Media S.A., 2020-01-01) Bahamon D.; Alkhatib I.I.I.; Alkhatib N.; Builes S.; Sinnokrot M.; Vega L.F.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe possibilities offered by molecular modeling tools to obtain relevant data at process conditions, while also gaining molecular insights on the techniques used for CO2 capture and separation, are presented here using selected case studies. Two different technologies, absorption with amine-based systems and adsorption on porous materials, were explored, using the molecular-based equation of state, soft-Statistical Associating Fluid Theory (SAFT), and Grand Canonical Monte Carlo simulations, respectively. The aqueous monoethanolamine (MEA) system was set as the benchmark for absorption and compared to the performance of 8 alternative amine-based systems, while 16 adsorbents belonging to different families (zeolites, metal–organic frameworks, amorphous silicas, and activated carbons), bare or functionalized with alkylamines, were investigated for the separation of CO2 by adsorption. In addition to obtaining molecular information on the CO2 capture process, the models were further used to examine the CO2 capture performance in terms of cyclic working capacity and energy index as key performance indicators, allowing the identification of promising systems that can improve the current ones to be further evaluated for separation in non-power industries. Results show that for the same total amine mass concentration, non-aqueous amine solvents have a 5–10% reduction in cyclic working capacity, and a 10–30% decrease in the energy index compared to their aqueous counterparts due to their lower heat of vaporization and specific heat capacity. In addition, M-MOF-74, NaX, and NaY structures present the best results for adsorption in temperature swing adsorption (TSA) processes. Similar values of energy requirements to those of amine-based systems (2–2.5 MJ kg CO2–1) were obtained for some of the adsorbent; however, the disadvantage of the TSA process versus absorption should be considered. These results confirm the reliability of molecular modeling as an attractive and valuable screening tool for CO2 capture and separation processes. © Copyright © 2020 Bahamon, Alkhatib, Alkhatib, Builes, Sinnokrot and Vega.Ítem Diseño conceptual de un reactor en fase gas-líquido para la producción de bicarbonato de sodio(Universidad EAFIT, 2014) Díez Montoya, Santiago; Jiménez Cañas, Luisa Fernanda; Acosta Maya, Diego AndrésSe diseñó conceptualmente la producción de bicarbonato de sodio por difusión de CO2 en una solución de carbonato de sodio, empleando un diseño estadístico de experimentos de superficie de respuesta (RSM) Box-Behnken, que permitió establecer las condiciones de operación óptimas -- Se encontró que a un flujo de 3 LPM de CO2, concentración inicial de 20% wt. de carbonado de socio y un tiempo de reacción de 1 hora y 56 minutos, se puede obtener una solución de bicarbonato de sodio con una concentraciòn de 5.59% wt. en solución -- Adicionalmente, a partir de ecuaciones básicas se determinaron las dimensiones de la columna y de los equipos necesarios para el proceso, con una inversión de capital aproximada de USD 509,700Ítem Diseño de un sistema de adsorción para la separación de CO2(Universidad EAFIT, 2022) Reinoso Rojas, Aminta Elena; Bermúdez Ríos, Carlos Arturo; Builes Toro, SantiagoÍtem Environmental improvement of operating supply chains: a multi-objective approach for the cement industry(Universidad EAFIT, 2017) Cadavid Giraldo, Nora; Vélez Gallego, Mario CésarNowadays companies worldwide face a growing pressure to reduce the environmental impact of their manufacturing activities -- However, the strategies used to achieve this goal are not clearly defined because of their conflicting relations with financial outcomes -- In parallel, globalization trends imply that as companies grow, usually through mergers and acquisitions, their supply chains become more complex -- The environmental improvement of these supply chains imply not only technical retrofit decisions aiming at adopting cleaner production technologies but also decisions regarding the structure of the supply chain itself -- Making these decisions becomes a difficult task because of the large number of variables involved, and the diversity of the interactions among them -- To tackle this problem, this research aims at providing a multi-objective solution approach for making technological retrofit decisions within an operating supply chain, so that both environmental and financial goals are best met -- The proposed solution approach is applied to the case of an operating cement supply chain in Colombia -- Several computational experiments were conducted, obtained results demonstrates that the proposed model is an e effective tool for multi-objective improvement decisions making, towards a more sustainable production processÍtem Evaluación de cepas de microalgas para captura de CO2(Universidad EAFIT, 2013) Giraldo Rave, Alejandra; Sáez Vega, Alex ArmandoLa captura de carbono a través del cultivo de microalgas se presenta como un nuevo esfuerzo en la reducción de la concentración de CO2 en la atmósfera -- Las microalgas son microorganismos de rápido crecimiento con velocidad de biofijación de CO2 relativamente alta, lo que le confiere una ventaja frente a otros sistemas biológicos para la captura de este compuesto -- Por eso es necesario que dichos sistemas funcionen de manera eficiente, garantizando el trabajo con especies de microalgas adecuadas y optimizándolos por medio del control de los parámetros que son importantes para el éxito de estos procesos -- Dicho lo anterior se realiza un proceso de investigación para seleccionar cuatro especies de microalgas prometedoras en cuanto a captura de CO2, bajo criterios de Producción de biomasa y Productividad, en donde se hizo necesario realizar ensayos de crecimiento con Aire y ensayos de crecimiento con Aire + CO2 con el fin de determinar características de crecimiento y potencialidades en cuanto a los parámetros de selección establecidos -- Fueron evaluadas en este estudio las cepas de microalgas provenientes de American Type Cullture Collection: Scenedesmus Obliquus ATCC 457, Scenedesmus armatus ATCC 429, Scenedesmus sp. ATCC 464, Chlorella kesslerii ATCC 468, Chlorella sp -- ATCC 853, Chlamydomonas moewusii ATCC 588 y de la Universidad de Texas: Chlorella sorokiniana UTEX 1230, Chlamydomonas reinhardtii UTEX 90 y Haematoccus pluvialis UTEX 2505 -- Los resultados obtenidos en estos ensayos, determinaron que la mayor potencialidad en cuanto a la fijación de CO2 la tenían las cepas ATCC 457, ATCC 588, UTEX 90 y UTEX 2505, para las cuales se plantea un estudio de medios de cultivo, que permita encontrar los parámetros donde se maximiza la producción de biomasa de cada una de estas cepas, mediante la variación de las concentraciones de los compuestos NaNO3 y K2HPO4 en el medio de cultivo -- 2 El estudio de las condiciones de cultivo que maximizan la producción de biomasa y la productividad se realizó mediante la metodología de superficie de respuesta, encontrando niveles óptimos para ambos parámetros dentro de la región experimental para las cepas ATCC 457, ATCC 588 y UTEX 2505, y en el caso de la cepa UTEX 90, los puntos de optimización, coinciden con un nivel de concentraciones evaluado dentro del estudioÍtem Evaluación de diferentes medios de cultivo para la obtención de biomasa microalgal con bajo contenido de nitrógeno utilizada en biofijación de CO2(Universidad EAFIT, 2020) Balcázar Naranjo, Alejandra; Miranda Parra, Alejandra Maria; Sáez Vega, Alex ArmandoÍtem Evaluación del crecimiento de Spirulina platensis UTEX 1926 cultivada en medios salinos, utilizando CO2 como fuente de carbono(Universidad EAFIT, 2017) Rojas Osorio, Daniela; Vargas Betancur, Gabriel Jaime; Sáez Vega, Alex ArmandoThe cell growth of Spirulina platensis and the production their metabolites, are affected by factors such as the supply of nutrients and physical-chemical parameters such as salinity, pH, temperature and light availability -- The reduction of the use of fresh water and the reduction of production costs of Spirulina platensis culture; the use of sea water is implemented, due to its content of several inorganic constituents that are available to the primaries producers such as microalgae and cyanobacteria -- In this study the cell growth of the Spirulina platensis UTEX 1926 and the production of metabolites under various concentrations of salinity, sodium nitrate and dipotassium phosphate were evaluated in order to obtain the most suitable condition and the understanding of physiological that intervene in the metabolism of cyanobacteria -- A Central Composite Design (CCD) was applied and each treatment was performed thrice -- The strain was cultivated in 1000mL flasks, with an air stream enriched with 7% CO2, photoperiod 12:12 under artificial light (LED) with an intensity of 55±4μmol/m2s and temperature on average 27°C±3 -- The results showed that Spirulina platensis UTEX 1926 reached a cellular concentration of 2197mg/L when concentrations of 38,546g/L, 0,727g/L, 0,855g/L salinity, sodium nitrate and dipotassium phosphate respectively were used -- In addition, under these concentrations of nutrients, 203mg/L of proteins, 4mg/L of phycocyanin and 3mg/L of exopolysaccharides were obtained -- Finally the cost per unit of mass is 0,19US for the chosen condition, being a means of low cost compared to the Zarrouk medium (0,74US per unit mass)Ítem Green CFLP: Modelo bi-objetivo de localización de instalaciones con restricciones sobre los impactos ambientales(Universidad EAFIT, 2016) Hincapié Osorno, Gabriel Esteban; Vélez Gallego, Mario CésarÍtem Hybrid aminopolymer-silica materials for efficient CO2 adsorption(ROYAL SOC CHEMISTRY, 2015-01-01) López-Aranguren, P.; Builes S.; Fraile, J.; López-Periago, A.; Vega, L.F.; Domingo, C.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe present work focuses on the development of a new eco-efficient chemical method for the polymerization of aziridine to hyperbranched polyethyleneimine (PEI) into mesoporous silica by using compressed CO2 as a solvent, reaction medium and catalyst. PEI was in situ grafted into MCM-41 and silica gel substrates, with pore diameters of 3.8 and 9.0 nm, respectively. The optimal polymerization conditions were found by varying the reaction pressure (1.0-10 MPa), temperature (25-45°C) and time (20-400 min). The thermal stability analysis indicated that aminopolymer chains were covalently attached on the amorphous silica surface. The described compressed CO2 route for the synthesis of high amine content hybrid products (6-8 mmolN g-1) is a very fast method, with processing times in the order of few minutes even at very low working pressures (1.0 MPa), being a step forward in the design of efficient hybrid aminopolymer nanocomposites for CO2 capture. The adsorptive behavior of the prepared hybrid materials was experimentally established by recording the N2 (-196°C) and CO2 (25, 50 and 75°C) adsorption isotherms. Results were compared to molecular simulation studies performed using Grand Canonical Monte Carlo for either N2 or CO2 adsorbed on amino modified MCM-41, thus helping to elucidate the predominant PEI configuration present in the functionalized materials. © The Royal Society of Chemistry 2015.Ítem Supercritical CO2 extraction of oil and omega-3 concentrate from Sacha inchi (Plukenetia volubilis L.) from Antioquia, Colombia(Instituto de la Grasa, 2017-01-01) Triana-Maldonado, D.M.; Torijano-Gutiérrez, S.A.; Giraldo-Estrada, C.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Sacha inchi (Plukenetia volubilis L.) seeds were employed for oil extraction with supercritical CO2 at laboratory scale. The supercritical extraction was carried out at a temperature of 60 °C, pressure range of 400-500 bars and CO2 flow of 40-80 g/min. The maximum recovery was 58% in 180 min, favored by increasing the residence time of CO2 in the extraction tank. Subsequently, the process was evaluated at pilot scale reaching a maximum recovery of 60% in 105 min, with a temperature of 60 °C, pressure of 450 bars and CO2 flow of 1270 g/min. The fatty acid composition of the oil was not affected for an extraction period of 30-120 min. The Sacha inchi oil was fractionated with supercritical CO2 to obtain an omega-3 concentrate oil without finding a considerable increase in the proportion of this compound, due to the narrow range in the carbon number of fatty acids present in the oil (16-18 carbons), making it difficult for selective separation. © 2017 CSIC.