Examinando por Materia "CO2"
Mostrando 1 - 5 de 5
Resultados por página
Opciones de ordenación
Ítem Early Miocene CO2 estimates from a Neotropical fossil leaf assemblage exceed 400 ppm(Wiley-Blackwell Publishing Ltd, 2018-11-01) Londoño L.; Royer D.L.; Jaramillo C.; Escobar J.; Foster D.A.; Cárdenas-Rozo A.L.; Wood A.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y ConservaciónPremise of the Study: The global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO2 records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate. Methods: In this study, we use a leaf gas-exchange model to estimate CO2 concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18.01 ± 0.17 Ma via 238U/206Pb zircon geochronology. We first validated the model for Neotropical environments by estimating CO2 from canopy leaves of 21 extant species in a natural Panamanian forest and from leaves of seven Neotropical species in greenhouse experiments at 400 and 700 ppm. Key Results: The results showed that the most probable combined CO2 estimate from the natural forests and 400 ppm experiments is 475 ppm, and for the 700 ppm experiments is 665 ppm. CO2 estimates from the five fossil species exhibit bimodality, with two species most consistent with a low mode (528 ppm) and three with a high mode (912 ppm). Conclusions: Despite uncertainties, it is very likely (at >95% confidence) that CO2 during the late early Miocene exceeded 400 ppm. These results revise upwards the likely CO2 concentration at this time, more in keeping with a CO2-forced greenhouse climate. © 2018 Botanical Society of AmericaÍtem Proceso de ASC - INSTRUMENTACION SISTEMA PARA LA CAPTURA DE CO2 A ESCALA DE LABORATORIO(Universidad EAFIT, 2021) Ochoa Botero, Emilio; Escobar Gallego, David; Dietl, Marcel; Builes, Santiago; Universidad EAFITThe increasing use of fossil fuels for energy generation and the high emission of greenhouse gases associated with these processes have made it necessary to develop technologies that can mitigate their impact. The chemical absorption process of CO2 using aqueous amines has been implemented in the industry for several decades and is considered a viable strategy for medium-term CO2 emissions mitigation. Pumping highly viscous fluids such as amines requires large amounts of energy, and they are commonly mixed with water to improve their fluidity. This mixture negatively impacts reaction rates, resulting in the need for larger equipment to capture the same amounts of CO2. Additionally, the regeneration process of aqueous amines requires the supply of large amounts of energy to increase their temperature and release the CO2. These kinetic and energetic characteristics of the process are the main obstacles to the widespread implementation and extensive use of this technology in the industry. This work continues the construction process of a plant for chemical absorption using aqueous amines. It builds upon the construction of a gas capture plant that took place in 2018, aiming to operate in a steady state and monitor the performance of different types of amines, amine mixtures, and operational conditions of the system in order to find alternatives that can reduce the energy cost of the process.Ítem Thermodynamic analysis of CO2 removal process by adsorption on NaX(Universidad EAFIT, 2021) Ortega Arcila, Laura; Serquera Mesa, Sebastián; Builes Toro, SantiagoThe continuous increase of carbon dioxide concentration in the atmosphere is the main contributor to climate change. Thus, it is imperative to develop strategies that help to control manmade emissions of this gas. Carbon dioxide capture is an intensive research area that aims to decrease the energy requirements for the separation and storage of CO2. Even though absorption using an aqueous solvent is a well-established and is the most widely implemented capture technology, it requires high energy for the regeneration of the solvent due to the need to increase the temperature of the aqueous solvent, decreasing the overall efficiency of the process. Adsorption using porous solids has been presented as an alternative process to capture CO2 while decreasing the energy requirements. In the present work, a thermodynamic analysis of the CO2 removal process by adsorption using literature reported data is performed, in order to devise a framework to evaluate and compare two adsorbents under realistic process conditions. Zeolites NaX and Beta were used as case studies to evaluate the proposed model. The results show that, although bed composition profiles have similar trends for both adsorbents, there is a significant difference in the regeneration temperature of these adsorbents, since for zeolite NaX the regeneration temperature is reached around 360K when CO2 is almost pure, whereas for Beta this value is reached around 390K. Thus, NaX has a lower energy requirement than Beta for stablished process conditions. The energy penalty is 91.08 MW per molCO2 recovered for NaX and 104.28 MW per molCO2 recovered for Beta, which is consistent with the calculation of the specific thermal energy and the working capacity.Ítem Transición energética en Alemania e integración de fuentes de energías no convencionales(Universidad EAFIT, 2019-12-01) Botero García, Jesús; Cardona Vásquez, David; García Rendón, John; jgarcia@eafit.edu.coGerman energy policy has undoubtedly been a worldwide benchmark for renewable energy. With the implementation of the Renewable Energy Sources Act in 2000, 36% of gross electricity consumption in 2018 came from renewable sources. In addition, greenhouse gas emissions fell by 328 million tonnes between 1990 and 2016. However, this has also increased the cost of stabilizing the grid, reaching a new record of 1.4 billion euros in 2017 and the price to the final consumer increased substantially, being one of the highest in the European Union. However, it has already been reducing, as it has reduced the cost of new technologies. Even so, the consensus of society is that these extra costs are worth paying. Therefore, it is important to know the energy transition program that Germany has experienced and its effects, which is the objective of this paper.Ítem Transición energética en Reino Unido para la integración de fuentes no convencionales de energía y redes inteligentes(Universidad EAFIT, 2019-12-01) Botero García, Jesús; Arbelaez, Juan Camilo; Garcia Rendon, John Jairo; jgarcia@eafit.edu.co; jabotero@eafit.edu.coThis paper describes the UK's energy transition to achieve 25% renewable energy generation by 2016 and reduce per capita CO2 emissions from 10,744.1 kg CO2/pc in 1990 to 6,560.2 in 2016. But at the same time, studies are beginning to show that although the reform of the electricity market in the United Kingdom has taken a big step forward, it still faces serious challenges due to the reduction of support mechanisms for renewable energy and the political instability that this economy has had, and, therefore, investors have chosen to concentrate on managing their existing assets rather than planning for further growth.