DSpace Repository :: Browsing by Subject "DIOXIDO DE CARBONO"

Browsing by Subject "DIOXIDO DE CARBONO"

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Already used and candidate polymeric membranes for CO2 separation plants
(2018) Gutiérrez, Juan Pablo; Ale Ruiz, Elisa Liliana; Erdmann, Eleonora
"This chapter presents the already used polymeric membranes and the potential candidates for the CO2 acid gas separation. Mainly, this work describes the characteristics of each membrane and the differences according to transport properties, conditions, and quality of the products. In addition to this, the types of membranes according to their capacity to separate CO2 from sources such as CO2/CH4 mixture, natural gas, and flue gases are also described. Also, the energy requirement to accomplish a certain product specification is introduced, this last used for the transport of natural gas. Finally, the characteristics of the potential candidate membranes and challenges for industrial applications are summarized."
Dead space analysis at different levels of positive end-expiratory pressure in acute respiratory distress syndrome patients
(2018-06) Gogniat, Emiliano; Ducrey, Marcela; Dianti, José; Madorno, Matías; Roux, Nicolás; Midley, Alejandro; Raffo, Julio; Giannasi, Sergio; San Román, Eduardo; Suárez-Sipmann, Fernando; Tusman, Gerardo
"To analyze the effects of positive end-expiratory pressure (PEEP) on Bohr's dead space (VDBohr/VT) in patients with acute respiratory distress syndrome (ARDS)."
Decarbonisation of the Argentinian transport sector by the introduction of battery electric vehicles
(2018) Costantini, Patricio; Turturro, Gastón Andrés
"The thermochemical decomposition of beech wood biomass results in a poor quality bio-oil, which cannot be directly used in diesel engines. In order to make this oil resemble liquid fossil fuels, an upgrading technique should be applied. Among the available possibilities, hydrodeoxygenation (the removal of oxygen and saturation of double bonds through high pressure hydrogen) appears to be the most auspicious route to produce biofuels. Besides, this method requires a catalyst to increase the activity, which could be reused in further upgrading reactions so as to minimize the generation of waste material. In this work, four nickel-based catalysts were evaluated for the hydrodeoxygenation of beech wood bio-oil. After being synthesized, their superficial and compositional characteristics were assessed. Once the upgrading reaction was performed for the pyrolysis oil, the resulting products (upgraded bio-oil, aqueous phase and gas fraction) were separately analyzed. Considering the obtained results, the catalyst with the best upgrading performance was selected in order to regenerate and use it in further hydrodeoxygenation reactions. The catalyst selection was based on upgraded bio-oil, catalyst and reaction factors. Parameters such as carbon, oxygen and water content, HHV, pH value, poisoning and overall hydrogen consumption were taken into account. With the obtained results, Ni/SiO2 was chosen and therefore regenerated, which included the calcination and reduction of the spent catalyst before it was reused in a new hydrodeoxygenation reaction. Its performance was tested along three consecutive reactions and the quality of upgraded bio-oils corresponding to these cycles were evaluated. It could be concluded that Ni/SiO2 showed an improvement in the upgraded bio-oil quality next to a satisfactory performance after the three regeneration cycles, which points out that this particular catalyst can be regenerated and reused for a minimum of three times without significantly affecting the resulting upgraded bio-oil quality. Further characterization techniques should be performed in order to achieve a bigger understanding of the functioning of nickel-based catalysts and their reutilization in a larger number of consecutive upgrading reactions."
Effect of PEEP on dead space in an experimental model of ARDS
(2020) Tusman, Gerardo; Gogniat, Emiliano; Madorno, Matías; Otero, Pablo; Dianti, José; Fernández Ceballos, Ignacio; Ceballos, Martín; Verdier, Natalí; Böhm, Stephan H.; Rodríguez, Pablo Oscar; San Román, Eduardo
"Background: Difference between Bohr and Enghoff dead space are not well described in ARDS patients. We aimed to analyze the effect of PEEP on the Bohr and Enghoff dead spaces in a model of ARDS. Methods: 10 pigs submitted to randomized PEEP steps of 0, 5, 10, 15, 20, 25 and 30 cm H2O were evaluated with the use of lung ultrasound images, alveolar-arterial oxygen difference (P(A-a)O2), transpulmonary mechanics, and volumetric capnography at each PEEP step. Results: At PEEP > 15 cm H2O, atelectasis and P(A-a)O2 progressively decreased while endinspiratory transpulmonary pressure (PL), end-expiratory PL, and driving PL increased (all P < .001). Bohr dead space (VDBohr/VT), airway dead space (VDaw/VT), and alveolar dead space (VDalv/VTalv) reached their highest values at PEEP 30 cm H2O (0.69 0.10, 0.53 0.13 and 0.35 0.06, respectively). At PEEP <15 cm H2O, the increases in atelectasis and P(A-a)O2 were associated with negative end-expiratory PL and highest driving PL. VDBohr/VT and VDaw/VT showed the lowest values at PEEP 0 cm H2O (0.51 0.08 and 0.32 0.08, respectively), whereas VDalv/VTalv increased to 0.27 0.05. Enghoff dead space and its derived VDalv/VTalv showed high values at low PEEPs (0.86 0.02 and 0.79 0.04, respectively) and at high PEEPs (0.84 0.04 and 0.65 0.12), with the lowest values at 15 cm H2O (0.77 0.05 and 0.61 0.11, respectively; all P < .001). CONCLUSIONS: Bohr dead space was associated to lung stress, whereas Enghoff dead space was partially affected by the shunt effect. Key words: dead space; PEEP; lung stress; ARDS; VILI; carbon dioxide."
Multi-objective optimization of a CO2-EOR process from the sustainability criteria
(2018-01) Gutiérrez, Juan Pablo; Erdmann, Eleonora; Manca, Davide
"Aim of this article is to estimate and discuss the economic and environmental impacts for the obtainment of CO2 in such conditions to be injected as enhanced oil recovery (EOR) fluid. Particularly, this study focuses on the compression sector design needed to process the CO2 coming from an already existing absorption plant. Currently, 18.68 kmol/h of a high-purity CO2 stream may be used for injecting and increasing the production of a pilot crude oil well near the location of the industrial plant. However, it is still necessary to perform an economic evaluation to quantify the investment and the operating costs that the compression involves..."
Optimización de la movilidad y miscibilidad de CO2 para EOR y almacenamiento de dióxido de carbono en reservorios heterogéneos
(2022-07) Gallo Jiménez, Gonzalo Augusto; Erdmann, Eleonora; Cavasotto, Claudio N.
"El CO2 EOR es una opción de CCUS con una capacidad de mitigación de CO2 excepcional y que contribuye a la soberanía energética. Esta tecnología tiene tres limitaciones para su implementación: la captura de CO2 en las condiciones técnicas y económicas necesarias, la baja viscosidad del gas y las elevadas presiones de miscibilidad. Este trabajo tiene un enfoque integral en el cual se busca ofrecer soluciones a cada una de estas limitaciones."
Simulación de la curva de capnografía a partir modelo matemático descriptivo de la vía aérea
(2019) Racca, Dora María
"Desarrollo de un modelo matemático descriptivo de la vía aérea que permite la simulación de la curva de capnografía en tiempo y volumen. Validación del sistema y su implementación en un simulador de mecánica respiratoria para entrenamiento médico."
Simulación del capnograma y estimación de parámetros respiratorios a partir de un modelo matemático descriptivo de la vía aérea
(2018) Racca, Dora María; Madorno, Matías
"La necesidad de ventilación mecánica es la principal causa de internación en unidades de terapia intensiva. Establecer la estrategia óptima de ventilación suele ser una tarea que requiere extenso conocimiento y esta puede ser realizada, en momentos de emergencia, sin el adecuado conocimiento de la fisiopatología del paciente. La evaluación cuantitativa de modelos de la fisiología respiratoria permite comprender el funcionamiento del sistema modelado, además de asistir en la predicción de comportamientos basado en variables de entrada o de salida. El presente trabajo busca ampliar el conocimiento cuantitativo de la fisiología respiratoria de los pacientes con asistencia ventilatoria mecánica a través del uso de un modelo descriptivo de la vía aérea."
Simulation of viscosity enhanced CO2 nanofluid alternating gas in light oil reservoirs
(2017-05) Gallo Jiménez, Gonzalo Augusto; Erdmann, Eleonora
"Thickened CO2 nanofluids are a mean to improve volumetric sweep efficiency and gas production in CO2 EOR projects in contrast CO2 flooding. Alternating injection of plain CO2 with thickened CO2 nanofluid is proposed as an economical alternative using the findings of CO2 viscosity enhancement through nanoparticles in current studies. This was achieved by using CMG GEM simulator and contrasting findings with other WAG and CO2 flooding simulations. The simulation was done on a light oil (40 °API) from a Neuquén Basin reservoir. A sensitivity analysis was done to contrast different type of injection schemes. As CO2 nanofluids can be tailor made in order to adjust their viscosity (and other properties like asphaltene deposition control) diverse results were observed. Nanofluids improve the volumetric sweet efficiency, and even low viscosity increment increase the overall gas utilization and conformance compared to CO2 flooding. Since there is no face change, the use of CO2 based nanofluids can be a mean to control CO2 EOR projects avoiding injectivity loss problems. It was observed that injection of mere nanofluid (without alternating CO2) is not technically nor economically convenient as it decreases production rates and has an overall lower economic performance than both WAG and CO2 flooding. Nevertheless, alternating nanofluid with plain CO2 enables higher sweep efficiency while lowering the operational costs due to lower volumes of nanofluid utilized. Adding nanofluid to a WAG scheme also shows improvements in EOR performance."
Steady-state energy optimization and transition assessment in a process of CO2 absorption from natural gas
(2018-09) Gutiérrez, Juan Pablo; Tarifa, Enrique E.; Erdmann, Eleonora
"An industrial-scale MDEA-based CO2 absorption process is considered in this work. Natural gas plant of Aguaragüe Argentina is selected to perform the studies of optimization and dynamics. With the steadystate of the process simulated, the reboiler energy demand of the plant is optimized in Aspen Hysys v8.8. In this optimization study, we analyze the base case (current) conditions of the reference plant and also six disturbance scenarios. According to the results, the main energy requirement can be reduced in more than a 48%, with the current process design. In the second part of our work, the plant is simulated in dynamic mode with the aim of characterizing the transition towards the found optimal conditions. It is proved that the dynamic model can reproduce the specified values after a short-time. In addition, the absence of undesirable states during the stabilization proves that the current control scheme is appropriate to minimize the energy consume in the plant under study."
Thermohydraulic investigation on the use of carbon dioxide as coolant for a solid breeding blanket for DEMO
(2017) Caspari, Felix; Boccaccini, Lorenzo V.; Hernández González, Francisco A.; Smoglie, Cecilia
"The Helium Cooled Pebble Bed (HCPB) Breeding Blanket (BB) is one of the 4 BB concepts being investigated in the EU for their possible implementation in a demonstration nuclear fusion reactor (DEMO). The choice of He as fuid coolant for the BB is motivated by a virtually complete transparency to neutrons, leaving unafected the T production capabilities of the blanket, as well as chemical inertness, molecular stability under high temperatures and neutron irradiation and a superior heat conductivity and capacity, leading to the best cooling performance in terms of heat transfer capabilities among other gas cooling choices. However, this cooling performance figure is hindered by the very low density of the gas, which leads to large pressure drops and high pumping power, thus afecting the overall plant efficiency, as well as to chronic leakages and large coolant inventories. These disadvantages, together with the still immature technology readiness of the respective turbomachinery, the price of this coolant, as well as its recognized limited resources pose concerns about the use of He as coolant for a BB in DEMO. On the other side, carbon dioxide has been the fuid coolant choice since the 50's in the nuclear fission industry for gas cooled reactors (MAGNOX, AGR). Despite its lower heat capacity and thermal conductivity (about 22% and 17% of that of helium respectively), its larger density (11 times larger molecular weight for CO2) can lead to an advantageous performance on heat dissipation rate per unit of pumping power. This feature, coupled with its relative transparency to neutrons, the molecular stability at the operating temperatures of the BB and the industrial scale ready turbomachinery makes CO2 an attractive alternative to He. The feasibility of a CO2-cooled breeding blanket is assessed in this work from the point of view of the thermohydraulic performance."

Browsing by Subject "DIOXIDO DE CARBONO"

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