Bibliografias temáticas / CO2 chemical absorption

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Literatura científica selecionada sobre o tema "CO2 chemical absorption"

Autor: Grafiati

Publicado: 21 de dezembro de 2024

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Artigos de revistas sobre o assunto "CO2 chemical absorption"

Saito, Satoshi. "CO2 Capture Technology by Chemical Absorption". MEMBRANE 47, n.º 6 (2022): 317–22. http://dx.doi.org/10.5360/membrane.47.317.

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Lamas Galdo, M. I., J. D. Rodriguez García e J. M. Rebollido Lorenzo. "Numerical Model to Analyze the Physicochemical Mechanisms Involved in CO2 Absorption by an Aqueous Ammonia Droplet". International Journal of Environmental Research and Public Health 18, n.º 8 (13 de abril de 2021): 4119. http://dx.doi.org/10.3390/ijerph18084119.

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CO2 is the main anthropogenic greenhouse gas and its reduction plays a decisive role in reducing global climate change. As a CO2 elimination method, the present work is based on chemical absorption using aqueous ammonia as solvent. A CFD (computational fluid dynamics) model was developed to study CO2 capture in a single droplet. The objective was to identify the main mechanisms responsible for CO2 absorption, such as diffusion, solubility, convection, chemical dissociation, and evaporation. The proposed CFD model takes into consideration the fluid motion inside and outside the droplet. It was found that diffusion prevails over convection, especially for small droplets. Chemical reactions increase the absorption by up to 472.7% in comparison with physical absorption alone, and evaporation reduces the absorption up to 41.9% for the parameters studied in the present work.

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Ho, Chii-Dong, Luke Chen, Jr-Wei Tu, Yu-Chen Lin, Jun-Wei Lim e Zheng-Zhong Chen. "Investigation of CO2 Absorption Rate in Gas/Liquid Membrane Contactors with Inserting 3D Printing Mini-Channel Turbulence Promoters". Membranes 13, n.º 12 (4 de dezembro de 2023): 899. http://dx.doi.org/10.3390/membranes13120899.

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The CO2 absorption by Monoethanolamine (MEA) solutions as chemical absorption was conducted in the membrane gas absorption module with inserting 3D mini-channel turbulence promoters of the present work. A mathematical modeling of CO2 absorption flux was analyzed by using the chemical absorption theory based on mass-transfer resistances in series. The membrane absorption module with embedding 3D mini-channel turbulence promoters in the current study indicated that the CO2 absorption rate improvement is achieved due to the diminishing concentration polarization effect nearby the membrane surfaces. A simplified regression equation of the average Sherwood number was correlated to express the enhanced mass-transfer coefficient of the CO2 absorption. The experimental results and theoretical predictions showed that the absorption flux improvement was significantly improved with implementing 3D mini-channel turbulence promoters. The experimental results of CO2 absorption fluxes were performed in good agreement with the theoretical predictions in aqueous MEA solutions. A further absorption flux enhancement up to 30.56% was accomplished as compared to the results in the previous work, which the module was inserted the promoter without mini channels. The influences of the MEA absorbent flow rates and inlet CO2 concentrations on the absorption flux and absorption flux improvement are also illustrated under both concurrent- and countercurrent-flow operations.

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Villarroel, Josselyne A., Alex Palma-Cando, Alfredo Viloria e Marvin Ricaurte. "Kinetic and Thermodynamic Analysis of High-Pressure CO2 Capture Using Ethylenediamine: Experimental Study and Modeling". Energies 14, n.º 20 (19 de outubro de 2021): 6822. http://dx.doi.org/10.3390/en14206822.

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One of the alternatives to reduce CO2 emissions from industrial sources (mainly the oil and gas industry) is CO2 capture. Absorption with chemical solvents (alkanolamines in aqueous solutions) is the most widely used conventional technology for CO2 capture. Despite the competitive advantages of chemical solvents, the technological challenge in improving the absorption process is to apply alternative solvents, reducing energy demand and increasing the CO2 captured per unit of solvent mass. This work presents an experimental study related to the kinetic and thermodynamic analysis of high-pressure CO2 capture using ethylenediamine (EDA) as a chemical solvent. EDA has two amine groups that can increase the CO2 capture capacity per unit of solvent. A non-stirred experimental setup was installed and commissioned for CO2 capture testing. Tests of the solubility of CO2 in water were carried out to validate the experimental setup. CO2 capture testing was accomplished using EDA in aqueous solutions (0, 5, 10, and 20 wt.% in amine). Finally, a kinetic model involving two steps was proposed, including a rapid absorption step and a slow diffusion step. EDA accelerated the CO2 capture performance. Sudden temperature increases were observed during the initial minutes. The CO2 capture was triggered after the absorption of a minimal amount of CO2 (~10 mmol) into the liquid solutions, and could correspond to the “lean amine acid gas loading” in a typical sweetening process using alkanolamines. At equilibrium, there was a linear relationship between the CO2 loading and the EDA concentration. The CO2 capture behavior obtained adapts accurately (AAD < 1%) to the kinetic mechanism.

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Dinul, Fadhilah Ikhsan, Hendri Nurdin, Dieter Rahmadiawan, Nasruddin, Imtiaz Ali Laghari e Tarig Elshaarani. "Comparison of NaOH and Na2CO3 as absorbents for CO2 absorption in carbon capture and storage technology". Journal of Engineering Researcher and Lecturer 2, n.º 1 (27 de abril de 2023): 28–34. http://dx.doi.org/10.58712/jerel.v2i1.23.

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CO2 gas is a greenhouse gas that causes global warming. Greenhouse gases are gases in the atmosphere that can absorb and reflect infrared radiation from the Earth's surface. Currently, the energy demand still depends on fossil fuels. On the other hand, CO2 emissions from burning fossil fuels continue to increase and contribute as greenhouse gases to the atmosphere. CO2 capture is an effort to reduce the burden of CO2 emissions into the atmosphere and is part of the Carbon, Capture, and Storage (CCS) protocol. The CO2 absorption process applied in the chemical industry is one of the CO2 absorptions using NaOH and Na2CO3 solutions as absorbents. This research aims to determine the effect of absorbent flow rate on the percentage of absorbed CO2. The method used in this research is the SLR (Systematic Literature Review) method to identify all available research. The absorbent flow rate variations used are 1 liter/minute, 1.5 liters/minute, 2 liters/minute, 2.5 liters/minute, and 3 liters/minute. The absorption process using NaOH absorbent is capable of absorbing CO2 gas with a maximum absorption of 95.52% and a minimum of 79.14%. Meanwhile, in the Na2CO3 absorbent, it is capable of absorbing CO2 gas with a maximum amount absorbed of 72.45% and a minimum of 35.47%.

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Ho, Chii-Dong, Hsuan Chang, Jr-Wei Tu, Jun-Wei Lim, Chung-Pao Chiou e Yu-Jie Chen. "Theoretical and Experimental Studies of CO2 Absorption in Double-Unit Flat-Plate Membrane Contactors". Membranes 12, n.º 4 (29 de março de 2022): 370. http://dx.doi.org/10.3390/membranes12040370.

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Theoretical predictions of carbon dioxide absorption flux were analyzed by developing one-dimensional mathematical modeling using the chemical absorption theory based on mass-transfer resistances in series. The CO2 absorption into monoethanolamine (MEA) solutions was treated as chemical absorption, accompanied by a large equilibrium constant. The experimental work of the CO2 absorption flux using MEA solution was conducted in double-unit flat-plate membrane contactors with embedded 3D turbulence promoters under various absorbent flow rates, CO2 feed flow rates, and inlet CO2 concentrations in the gas feed stream for both concurrent and countercurrent flow operations. A more compact double-unit module with embedded 3D turbulence promoters could increase the membrane stability to prevent flow-induced vibration and enhance the CO2 absorption rate by overwhelming the concentration polarization on the membrane surfaces. The measured absorption fluxes with a near pseudo-first-order reaction were in good agreement with the theoretical predictions for the CO2 absorption efficiency in aqueous MEA solutions, which was shown to be substantially larger than the physical absorption in water. By embedding 3D turbulence promoters in the MEA feed channel, the new design accomplishes a considerable CO2 absorption flux compared with an empty channel as well as the single unit module. This demonstrates the value and originality of the present study regarding the technical feasibility. The absorption flux enhancement for the double-unit module with embedded 3D turbulence promoters could provide a maximum relative increase of up to 40% due to the diminution in the concentration polarization effect. The correlated equation of the average Sherwood number was obtained numerically using the fourth Runge–Kutta method in a generalized and simplified expression to calculate the mass transfer coefficient of the CO2 absorption in the double-unit flat-plate membrane contactor with turbulence promoter channels.

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Jamaludin, Siti Nabihah, e Ruzitah Mohd Salleh. "Research Trends of Carbon Dioxide Capture using Ionic Liquids and Aqueous Amine-Ionic Liquids Mixtures". Scientific Research Journal 13, n.º 1 (30 de junho de 2016): 53. http://dx.doi.org/10.24191/srj.v13i1.5442.

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Anthropogenic CO2 emissions has led to global climate change and widely contributed to global warming since its concentration has been increasing over time. It has attracted vast attention worldwide. Currently, the different CO2 capture technologies available include absorption, solid adsorption and membrane separation. Chemical absorption technology is regarded as the most mature technology and is commercially used in the industry. However, the key challenge is to find the most efficient solvent in capturing CO2. This paper reviews several types of CO2 capture technologies and the various factors influencing the CO2 absorption process, resulting in the development of a novel solvent for CO2 capture.

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Jamaludin, Siti Nabihah, e Ruzitah Mohd Salleh. "Research Trends of Carbon Dioxide Capture using Ionic Liquids and Aqueous Amine-Ionic Liquids Mixtures". Scientific Research Journal 13, n.º 1 (1 de junho de 2016): 53. http://dx.doi.org/10.24191/srj.v13i1.9382.

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Selvi, Pongayi, e Rajoo Baskar. "CO2 absorption in nanofluid with magnetic field". Chemical Industry and Chemical Engineering Quarterly, n.º 00 (2020): 8. http://dx.doi.org/10.2298/ciceq181225008s.

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Acidic gases like CO2, SO2, NO2, H2S etc., are to be removed as these are polluting the atmosphere in one way or another by inducing temperature rise which further results in undesirable climatic change. Among all these gases CO2 is the most responsible for the environmental issues and its capture becomes prime importance. The objective of this work is the enhancement of the CO2 absorption by employing nanofluids in the presence of magnetic field. The nanofluid used in this work is Al2O3/water in the concentration of 0.0015 %. The maximum flux obtained is 0.014 mol/m2s(without magnetic field) and 0.015 mol/m2s(with magnetic field) for lower CO2 flow rate of 30 LPH. Hence the nanofluids along with magnetic field shows the positive performance towards the absorption of CO2.

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Lívanský, Karel. "Kinetics of pH equilibration in solutions of hydrogen carbonate during bubbling with a gas containing carbon dioxide". Collection of Czechoslovak Chemical Communications 50, n.º 3 (1985): 553–58. http://dx.doi.org/10.1135/cccc19850553.

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The kinetics of the title process is approximated by differential equations based on kinetic and equilibrium data for carbon dioxide. The course of pH after a sudden change of the concentration of CO2 in the gas is calculated by numerical integration. The course of pH during absorption of CO2 is different from that during desorption. The course of pH during desorption calculated on the assumption that the rate of the noncatalysed hydration of CO2 is sufficient to ensure chemical equilibrium is in good agreement with experimental data from the literature. During absorption of CO2 in a solution of hydrogen carbonate, the chemical reaction rate is sometimes insufficient to ensure chemical equilibrium prior to pH measurement.

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Mais fontes

Teses / dissertações sobre o assunto "CO2 chemical absorption"

Joakim, Gustavsson, e Lager Niclas. "Absorption av CO2 i ammoniaklösning". Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211844.

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I detta arbete studeras absorption av växthusgasen koldioxid (CO2) i ammoniaklösning. Målet med arbetet är att undersöka hur väl teknik med vegetabilisk olja kan förhindra avdunstning av ammoniaklösning vid absorptionen och på så vis främja grön kemi. En jämförelse görs sedan med en mer beprövad teknik med nedkylning. Därefter undersöks vilka salter som fälls ut vid absorptionen vid de båda teknikerna samt olika koncentration ammoniak (NH3). Genom att blanda ammoniak, etanol (C2H5OH) och vatten (H2O) i olika förhållanden i ett absorptionstorn erhölls den absorberande lösningen. CO2 i gasform fördes sedan in i reaktorn. I genomförda experiment gav teknik med vegetabiliskt oljemembran samma eller lägre materialförlust av ammoniaklösning som teknik med nedkylning. Högre halt av etanol innebar sänkt löslighet av ammoniumsalter vilket gav större utfällning av salter i utförda experiment. Detta kan observeras genom att jämföra kristallvikten i utförda experiment. Kristallerna analyserades med röntgendiffraktion (XRD). Salterna kunde identifieras genomatt jämföra erhållet resultat med standardprov från litteratur. Dock fanns avvikelser mellanresultatet och standardprov, vilket gjorde analysen svårtolkad.

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Leifsen, Henning. "Post-Combustion CO2 Capture Using Chemical Absorption : Minimizing Energy Requirement". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12865.

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Capture and storage from fossil fuel fired power plants is drawing increasing interest as a potential method for the control of greenhouse gas emissions. An optimization and technical parameter study for a CO2 capture process of the flue gas of a commercial gas power plant, based on absorption/desorption process with MEA solutions, using HYSYS with the Amine Property Package fluid package, has been performed. The optimization has aimed to reduce the energy requirement for solvent regeneration, by investigating the effects of circulation rate, cross-flow heat exchanger minimum approach, desorber operating pressure and the absorber diameter. In addition, an economic evaluation including investment cost has been performed for the first three parameters.Major energy savings can be realized by optimizing the desorber pressure and the solvent circulation rate. The circulation rate will have a clearly defined optimal point, while for the desorber pressure the temperature will be a limiting factor. A too high temperature may lead to amine degradation and corrosion problems. The cross-flow heat exchanger minimum temperature approach will not affect the energy consumption significantly. An optimum absorber column diameter was not found, but the column should be designed with a diameter large enough to prevent flooding through the column. A too large diameter will not favour the energy consumption very much, and other factors will be more decisive when the column diameter is chosen.

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Nookuea, Worrada. "Impacts of Thermo-Physical Properties on Chemical Absorption for CO2 Capture". Licentiate thesis, Mälardalens högskola, Framtidens energi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-34254.

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Following the climate change mitigation target in Paris agreement, the global warming has to be limited to 2.0°C above the preindustrial levels. One of the potential methods is carbon capture and storage (CCS), which can significantly reduce the CO2 emissions from the vast point sources such as power plants, industries, and natural gas processes. The CCS covers four steps which are capture, conditioning, transport, and storage. For the capture part, post-combustion capture is easier to implement based on today’s technologies and infrastructure compared with pre-combustion and oxy-fuel combustion captures, since the radical changes in the structure of the existing plant are not required. To design and operate different CCS processes, the knowledge of thermo-physical properties of the CO2 mixtures is of importance. In this thesis, the status and progress of the studies related to the impacts of the uncertainty in thermo-physical properties on the design and operation of the CCS processes were reviewed. The knowledge gaps and the priority of property model development were identified. According to the identified knowledge gaps in the review, the impacts of thermo-physical properties which are the density, viscosity, and diffusivity of the gas and liquid phases, and the surface tension and heat capacity of the liquid phase on the design of the absorber column for the chemical absorption using aqueous monoethanolamine were quantitatively analyzed. An in-house rate-based absorption model was developed in MATLAB to simulate the absorption process, and the sensitivity study was done for each property. An economic evaluation was also performed to further estimate the impacts of the properties on the capital cost of the absorption unit. For column diameter of the absorber, the gas phase density shows the most significant impacts; while, the liquid phase density and viscosity show the most significant impacts on the design of the packing height and also the capital cost of the absorption unit. Therefore, developing the flue gas density model and liquid phase density and viscosity models of the aqueous solvents with CO2 loading should be prioritized.
Enligt Parisavtalets mål för klimatförändringar ska den globala uppvärmningen begränsas till 2.0° C över förindustriella nivåer. En av de potentiella metoderna är avskiljning och lagring av koldioxid (CCS), som avsevärt kan minska CO2-utsläppen från stora punktkällor såsom kraftverk, industrier och naturgasprocesser. CCS omfattar fyra steg som är avskiljning, konditionering, transport och lagring. Avskiljning genom efterförbränning är lättare att genomföra baserat på dagens teknik och infrastruktur jämfört med avskiljning före förbränning och genom oxybränsle förbränning, eftersom radikala förändringar av de befintliga anläggningars struktur inte behövs. För att utforma och driva olika CCS processer, är kunskap om termofysikaliska egenskaperna hos CO2 blandningarna av stor betydelse. I denna avhandling har status och framsteg för studier rörande effekterna av osäkerheten i termofysikaliska egenskaper på konstruktion och drift av CCS processer granskats. Kunskapsluckor och prioritering av utveckling av modeller för egenskaperna identifierades. Enligt de i översynen identifierade kunskapsluckorna, har effekterna av de termofysikaliska egenskaperna densitet, viskositet och diffusivitet av gas- och vätskefaserna, och ytspänningen och värmekapacitet av vätskefasen på utformningen av absorptionskolonnen för kemisk absorption med användning av vattenhaltig monoetanolamin analyserats kvantitativt. En hastighetsbaserad absorptionsmodell har utvecklats i MATLAB för simulering av absorptionsprocessen och känslighetsanalys gjordes för varje egenskap. En ekonomisk utvärdering genomfördes också för att ytterligare uppskatta effekterna av egenskaperna på kapitalkostnaden för absorptionsenheten. För bestämning av diametern av absorbatorns kolonn visar gasfasens densitet den mest betydande inverkan; medan vätskefasens densitet och viskositeten visar den mest betydande inverkan på utformningen av fyllmaterialets höjd och även kapitalkostnaderna för absorptionsenheten. Därför bör utveckling av modeller för rökgasens densitet och vätskefasens densitet och viskositet för det vattenbaserade lösningsmedlet med absorberad CO2 prioriteras.
VR CCS Project

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Neveux, Thibaut. "Modélisation et optimisation des procédés de captage de CO2 par absorption chimique". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0266/document.

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Les procédés de captage de CO2 par absorption chimique engendrent une importante pénalité énergétique sur la production électrique des centrales à charbon, constituant un des principaux verrous technologiques au déploiement de la filière. L'objectif de cette thèse est de développer et valider une méthodologie à même d'évaluer précisément le potentiel d'un procédé de captage aux amines donné. La phénoménologie de l'absorption chimique a été étudiée en détail et représentée par des modèles à l'état de l'art. Le modèle e-UNIQUAC a été utilisé pour décrire les équilibres chimiques et de phases des solutions électrolytiques et les paramètres du modèle ont été régressés pour quatre solvants. Un modèle hors-équilibre a été utilisé pour représenter le transfert couplé de matière et de chaleur, accéléré par les réactions chimiques. Les modèles ont été validés avec succès sur des données expérimentales d'un pilote industriel et d'un pilote de laboratoire. L'influence des phénomènes sur les efficacités de séparation a été explicitée afin d'isoler les phénomènes les plus impactants. Une méthodologie a alors été proposée pour évaluer la pénalité énergétique, incluant les consommations thermiques et électriques, liée à l'installation d'un procédé de captage sur une centrale à charbon supercritique. Une méthode d'estimation du coût de l'électricité est proposée pour quantifier les dépenses opératoires et d'investissement d'un tel procédé. L'environnement de simulation et d'évaluation de procédés obtenu a ensuite été couplé à une méthode d'optimisation afin de déterminer les paramètres opératoires et les dimensions des équipements maximisant les performances énergétiques et économiques
CO2 capture processes by chemical absorption lead to a large energy penalty on efficiency of coal-fired power plants, establishing one of the main bottleneck to its industrial deployment. The objective of this thesis is the development and validation of a global methodology, allowing the precise evaluation of the potential of a given amine capture process. Characteristic phenomena of chemical absorption have been thoroughly studied and represented with state-of-the-art models. The e-UNIQUAC model has been used to describe vapor-liquid and chemical equilibria of electrolyte solutions and the model parameters have been identified for four solvents. A rate-based formulation has been adopted for the representation of chemically enhanced heat and mass transfer in columns. The absorption and stripping models have been successfully validated against experimental data from an industrial and a laboratory pilot plants. The influence of the numerous phenomena has been investigated in order to highlight the most limiting ones. A methodology has been proposed to evaluate the total energy penalty resulting from the implementation of a capture process on an advanced supercritical coal-fired power plant, including thermal and electric consumptions. Then, the simulation and process evaluation environments have been coupled with a non-linear optimization algorithm in order to find optimal operating and design parameters with respect to energetic and economic performances

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TAVARES, DENISE T. "Análise quantitativa de alcanolaminas e CO2 no processo de absorção química via espectroscopia no infravermelho". reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26367.

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Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-06-22T10:57:18Z No. of bitstreams: 0
Made available in DSpace on 2016-06-22T10:57:18Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Oexmann, Jochen [Verfasser]. "Post-combustion CO2 capture : energetic evaluation of chemical absorption processes in coal-fired steam power plants / Jochen Oexmann". Hamburg : Universitätsbibliothek der TU Hamburg-Harburg, 2011. http://d-nb.info/1012653196/34.

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Li, Hailong. "Thermodynamic Properties of CO2 Mixtures and Their Applications in Advanced Power Cycles with CO2 Capture Processes". Doctoral thesis, KTH, Energiprocesser, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9109.

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The thermodynamic properties of CO2-mixtures are essential for the design and operation of CO2 Capture and Storage (CCS) systems. A better understanding of the thermodynamic properties of CO2 mixtures could provide a scientific basis to define a proper guideline of CO2 purity and impure components for the CCS processes according to technical, safety and environmental requirements. However the available accurate experimental data cannot cover the whole operation conditions of CCS processes. In order to overcome the shortage of experimental data, theoretical estimation and modelling are used as a supplemental approach. In this thesis, the available experimental data on the thermodynamic properties of CO2 mixtures were first collected, and their applicability and gaps for theoretical model verification and calibration were also determined according to the required thermodynamic properties and operation conditions of CCS. Then in order to provide recommendations concerning calculation methods for engineering design of CCS, totally eight equations of state (EOS) were evaluated for the calculations about vapour liquid equilibrium (VLE) and density of CO2-mixtures, including N2, O2, SO2, Ar, H2S and CH4. With the identified equations of state, the preliminary assessment of impurity impacts was further conducted regarding the thermodynamic properties of CO2-mixtures and different processes involved in CCS system. Results show that the increment of the mole fraction of non-condensable gases would make purification, compression and condensation more difficult. Comparatively N2 can be separated more easily from the CO2-mixtures than O2 and Ar. And a lower CO2 recovery rate is expected for the physical separation of CO2/N2 under the same separation conditions. In addition, the evaluations about the acceptable concentration of non-condensable impurities show that the transport conditions in vessels are more sensitive to the non-condensable impurities and it requires very low concentration of non-condensable impurities in order to avoid two-phase problems. Meanwhile, the performances of evaporative gas turbine integrated with different CO2 capture technologies were investigated from both technical and economical aspects. It is concluded that the evaporative gas turbine (EvGT) cycle with chemical absorption capture has a smaller penalty on electrical efficiency, while a lower CO2 capture ratio than the EvGT cycle with O2/CO2 recycle combustion capture. Therefore, although EvGT + chemical absorption has a higher annual cost, it has a lower cost of electricity because of its higher efficiency. However considering its lower CO2 capture ratio, EvGT + chemical absorption has a higher cost to avoid 1 ton CO2. In addition the efficiency of EvGT + chemical absorption can be increased by optimizing Water/Air ratio, increasing the operating pressure of stripper and adding a flue gas condenser condensing out the excessive water.
QC 20100819

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Rey, Stéphanie. "Fractionnement du poly(oxyde d'éthylène) et du polystyrène avec le mélange supercritique universel CO2/éthanol : approche du comportement microscopique et thermodynamique de ces systèmes". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1999. http://tel.archives-ouvertes.fr/tel-00007636.

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Deux polymères modèles de natures chimiques opposées, le poly(oxyde d'éthylène) et le polystyrène, ont été fractionnés par un mélange supercritique CO2/solvant (solvant : éthanol, acétone, tétrahydrofurane), en fonction de leurs masses molaires, à température constante et à pression variable. Les expériences de fractionnement ont été réalisées sur des échantillons linéaires et sur des polymères à architecture ou de structure chimique plus complexes (polymères en étoile, dendrimères, macrocycles, copolymères à blocs). La solubilité de ces polymères dans les mélanges supercritiques CO2/solvant ainsi que la sélectivité de ces milieux ont été évaluées. L'influence des paramètres, pression, température, nature chimique et quantité de solvant a été étudiée. Enfin, nous avons mené une étude spectroscopique afin de mieux comprendre l'organisation microscopique des systèmes polystyrène//CO2/éthanol. Parallèlement, une modélisation thermodynamique des équilibres de phases, par la méthode SAFT, a été initiée.

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Alie, Colin. "CO₂ Capture With MEA: Integrating the Absorption Process and Steam Cycle of an Existing Coal-Fired Power Plant". Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/796.

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In Canada, coal-fired power plants are the largest anthropogenic point sources of atmospheric CO₂. The most promising near-term strategy for mitigating CO₂ emissions from these facilities is the post-combustion capture of CO₂ using MEA (monoethanolamine) with subsequent geologic sequestration. While MEA absorption of CO₂ from coal-derived flue gases on the scale proposed above is technologically feasible, MEA absorption is an energy intensive process and especially requires large quantities of low-pressure steam. It is the magnitude of the cost of providing this supplemental energy that is currently inhibiting the deployment of CO₂ capture with MEA absorption as means of combatting global warming. The steam cycle of a power plant ejects large quantities of low-quality heat to the surroundings. Traditionally, this waste has had no economic value. However, at different times and in different places, it has been recognized that the diversion of lower quality streams could be beneficial, for example, as an energy carrier for district heating systems. In a similar vein, using the waste heat from the power plant steam cycle to satisfy the heat requirements of a proposed CO₂ capture plant would reduce the required outlay for supplemental utilities; the economic barrier to MEA absorption could be removed. In this thesis, state-of-the-art process simulation tools are used to model coal combustion, steam cycle, and MEA absorption processes. These disparate models are then combined to create a model of a coal-fired power plant with integrated CO₂ capture. A sensitivity analysis on the integrated model is performed to ascertain the process variables which most strongly influence the CO₂ energy penalty. From the simulation results with this integrated model, it is clear that there is a substantial thermodynamic advantage to diverting low-pressure steam from the steam cycle for use in the CO₂ capture plant. During the course of the investigation, methodologies for using Aspen Plus® to predict column pressure profiles and for converging the MEA absorption process flowsheet were developed and are herein presented.

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Hajj, Ali. "Coupling microwaves with a CO2 desorption process from amine solvent : experimental and modeling approaches". Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0412.

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Alors que les besoins énergétiques mondiaux continueront d’être satisfaits par des sources d’énergie fossiles, une solution viable pour réduire les émissions de CO2 serait de mettre en œuvre des technologies de captage du carbone. Le captage du CO2 par absorption dans des solvants aminés fait partie des technologies les plus avancées mises en œuvre sur les unités de post-combustion. Son application reste néanmoins limitée aux grandes sources ponctuelles, et les petites sources restantes difficiles à décarboner. Récemment, le chauffage microondes a gagné en popularité en raison de ses caractéristiques de sélectivité, de nature volumétrique et de facilité de contrôle ; d'autre part, les contacteurs à membrane sont des contacteurs gaz-liquide prometteurs en raison de leur compacité, de leur flexibilité opérationnelle et de leur facilité d'évolutivité par rapport aux colonnes à garnissage. Dans ce travail, nous explorons le fonctionnement de la désorption chimique lors d'un contacteur à membrane à fibres creuses par chauffage par micro-ondes.Une compréhension complète des interactions entre les champs microondes et les phénomènes de transfert est essentielle pour la conception, le fonctionnement et l’optimisation corrects d’un équipement à l’échelle industrielle. Ainsi, les taux de désorption du CO2 ont été étudiés expérimentalement à l'échelle locale d'une seule fibre millimétrique, placée dans une cavité micro-onde monomode. La modélisation numérique de la fibre a permis de visualiser les gradients de température formés à l'intérieur du solvant, et les taux de désorption locaux correspondants. En parallèle, une unité à l'échelle prototype a été conçue pour la désorption du CO2 à l'échelle d'un module à fibres creuses sous des champs microondes. À cette fin, nous avons conçu une cavité sur mesure pour abriter un module à membrane de telle manière que la désorption du CO2 aurait lieu simultanément avec le chauffage électromagnétique
As global energy needs will continue to be met by fossil-fuel based sources, a viable solution to reduce CO2 emissions would be to implement carbon capture technologies. CO2 capture by absorption in amine solvents ranks among the most advanced technologies to be implemented on post combustion units. Still, its application is remains constrained large point sources with small sources remaining difficult to decarbonize. Recently, microwave heating has gained in popularity due to its characteristics of selectiveness, volumetric nature, and ease of control; on the other hand, membrane contactors are promising gas-liquid contactors due to their compacity, operational flexibility, and ease scalability in comparison to packed columns. In this work we explore the operation of chemical desorption when a hollow fiber membrane contactor by microwave heating.A comprehensive understanding of the interactions of microwave fields and transfer phenomena is essential for the correct design, operation, and optimization of an industrial scale equipment. Hence CO2 desorption rates were experimentally studied at the local scale of a single millimetric fiber, placed in a mono-mode microwave cavity. Numerical modeling of the fiber allowed the visualization of the temperature gradients formed inside the solvent, and the corresponding local desorption rates. In parallel, a prototype-scale unit was designed for the desorption of CO2 at the scale of a hollow fiber module under microwave fields. To this end we designed a custom-design cavity was made to house a membrane module in such a manner that CO2 desorption would take place simultaneously with electromagnetic heating

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Livros sobre o assunto "CO2 chemical absorption"

Madeddu, Claudio, Massimiliano Errico e Roberto Baratti. CO2 Capture by Reactive Absorption-Stripping: Modeling, Analysis and Design. Springer, 2019.

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Capítulos de livros sobre o assunto "CO2 chemical absorption"

Vega, Fernando, Luz Marina Gallego-Fernández, David Abad-Correa e Francisco Manuel Baena-Moreno. "Advanced Fluids in Chemical Absorption of CO2". In Advanced Materials for a Sustainable Environment, 271–91. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003206385-12.

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Puxty, Graeme, Marcel Maeder e Robert Bennett. "Reactive Chemical Absorption of CO2 by Organic Molecules". In Sustainable Carbon Capture, 29–71. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003162780-2.

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He, Hui, Mengxiang Fang, Wei Yu, Qunyang Xiang, Tao Wang e Zhongyang Luo. "A Low-Cost Chemical Absorption Scheme for 500,000 t/y CO2 Capture Project". In Clean Coal Technology and Sustainable Development, 373–78. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-2023-0_50.

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Mehdizadeh, B., K. Vessalas, B. Ben, A. Castel, S. Deilami e H. Asadi. "Advances in Characterization of Carbonation Behavior in Slag-Based Concrete Using Nanotomography". In Lecture Notes in Civil Engineering, 297–308. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_30.

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AbstractExposure of concrete to the atmosphere causes absorption of CO2 and carbonation via a chemical reaction between the CO2 and calcium hydroxide and calcium-silicate-hydrate reaction products inside the concrete. A greater understanding of carbonation behavior and its micro- and nanoscale impacts is needed to predict and model concrete durability, cracking potential and steel depassivation behaviors. New and sophisticated techniques have emerged to analyze the microstructural behavior of concrete subjected to carbonation. High-resolution full-field X-ray imaging is providing new insights to nanoscale behavior. Full-field nano-images provide significant insight into 3D structural identification and mapping. Nanotomographic modeling of an accelerated carbonated test specimen can also provide a 3D view of the pore structure that resides inside slag-based concrete. This is critical for better understanding of the capillary porosity and pore solution behaviors of concrete in situ. We investigated the analysis of durability properties, including the carbonation behavior of slag-based concrete, by evaluating microstructural and nanotomographic identification techniques.

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Andrews, David L., e Kevin P. Hopkins. "Synergistic Effects in Two-Photon Absorption: the Quantum Electrodynamics of Bimolecular Mean-Frequency Absorption". In Advances in Chemical Physics, 39–102. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470141267.ch2.

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Birnbaum, G., B. Guillot e S. Bratos. "Theory of Collision-Induced Line Shapes-Absorption and Light Scattering at Low Density". In Advances in Chemical Physics, 49–112. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470142752.ch2.

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Kalmykov, Yuri P., e Sergei V. Titov. "A Semiclassical Theory of Dielectric Relaxation and Absorption: Memory Function Approach to Extended Rotational Diffusion Models of Molecular Reorientations in Fluids". In Advances in Chemical Physics, 31–123. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470141465.ch2.

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Gosnell, T. R., A. J. Taylor e J. L. Lyman. "Broadband Ultrafast Absorption Spectroscopy in the Hard Ultraviolet: Evolution of the CF2 Radical upon Photodissociation of CF2Br2". In Springer Series in Chemical Physics, 483–85. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84269-6_146.

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Yazgi, Murat, Alexander Olenberg e Eugeny Y. Kenig. "Complementary Modelling of CO2 Capture by Reactive Absorption". In Computer Aided Chemical Engineering, 1243–48. Elsevier, 2014. http://dx.doi.org/10.1016/b978-0-444-63455-9.50042-8.

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Okabe, Kazuhiro, Miho Nakamura, Hiroshi Mano, Masaaki Teramoto e Koichi Yamada. "CO2 separation by membrane/absorption hybrid method". In New Developments and Application in Chemical Reaction Engineering, 409–12. Elsevier, 2006. http://dx.doi.org/10.1016/s0167-2991(06)81620-4.

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Trabalhos de conferências sobre o assunto "CO2 chemical absorption"

Rob, Mohammad A., e Larry H. Mack. "Absorption Spectra of Propylene at Carbon Dioxide (CO2) Laser Wavelengths". In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/laca.1994.tub.7.

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Laser remote sensing techniques for detecting trace level atmospheric pollutants have made rapid advances in the past several years.1,2 Molecular CO2 lasers play an important role in atmospheric pollution monitoring, because its emission spectrum in the 9-11 μn range falls within the largest atmospheric window and which overlap with the absorption spectra of a large number of molecules of environmental concern.2 The primary pollutants that are emitted to the atmosphere by natural and anthropogenic processes are, hydrocarbons (HC), carbon oxides (CO, CO2), nitric oxides (NO, NO2), ammonia (NH3), sulfur dioxide (SO2), and etc.3 The primary pollutants also go through complex chemical reactions among themselves or with the natural atmospheric constituents, to form a variety of secondary pollutants.2,3 An understanding of the atmospheric chemical processes requires fast detection of primary and secondary pollutants while they reside in the atmosphere. Laser remote sensing techniques are suitable for the detection of these pollutants.

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Yun, Soung Hee, Young Eun Kim, Yo Han Seong, Sung Chan Nam, Il Soo Chu e Yeo Il Yoon. "CO2 Absorption of Chemical Phase Transitional Absorbents: Absorption Capacity and Reaction Mechanism". In Games and Graphics 2014. Science & Engineering Research Support soCiety, 2014. http://dx.doi.org/10.14257/astl.2014.65.02.

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Son, Juhee, Ji Eun Kim, Jo Hong Kang e Hojun Song. "Enriching CO2 Absorption Characteristics by Blending Diverse Amine Species". In 15th Mediterranean Congress of Chemical Engineering (MeCCE-15). Grupo Pacífico, 2023. http://dx.doi.org/10.48158/mecce-15.t4-p-12.

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Rob, Mohammad A., e Frank C. Franceschetti. "Atmospheric Multi-Component Pollution Analysis Using CO2 Laser". In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/laca.1992.wc7.

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The laser spectroscopic techniques for detecting minor gaseous pollutants of the atmosphere have made rapid advances in the last few years. The most important optical process for detection of air pollutants is based on the extinction of radiation by molecular absorption. Each molecule absorbs light at a particular wavelength or a range of wavelengths, a characteristic of the molecule. Thus a measurement of absorption of light at the molecule's characteristic wavelength produces a mean of determining a particular molecule at the presence of other molecules. Problems can, and often arise from overlapping spectrums due to other molecules of the atmosphere. In this case, it is necessary to identify the molecules which cause these overlappings. In some cases, one might be interested in finding multiple pollutants of the atmosphere.

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Mel, Maizirwan, Muhammad Amirul Hussin Sharuzaman e Roy Hendroko Setyobudi. "Removal of CO2 from biogas plant using chemical absorption column". In PROCEEDINGS OF THE 12TH INTERNATIONAL CONFERENCE ON SYNCHROTRON RADIATION INSTRUMENTATION – SRI2015. Author(s), 2016. http://dx.doi.org/10.1063/1.4958488.

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Mihalcea, R. M., D. S. Baer, R. K. Hanson e G. S. Feller. "Diode-laser absorption measurements of CO2, H2O, and N2O near 2 μm". In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lmc.21.

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A tunable external-cavity diode laser (ECDL) operating near 2.0 μm was used to perform absorption measurements of CO2, H2O, and N2O in a heated static cell at various pressures (15 - 760 torr) and temperatures (294 K - 1460 K). The present work represents an extension of previous diode-laser absorption measurements of weaker vibrational overtones near 1.5 μm1 and thus offers significantly higher measurement sensitivity. Absorption survey spectra of CO2, H2O, and N2O in the spectral region between 4866 cm−1 and 5118 cm−1 were recorded, compared to calculations (based on the HITRAN96 and HITEMP databases), and used to select the optimum transitions for concentration measurements. Individual transitions (1-cm−1 scans) were measured in order to determine line strength values and self broadening parameters.

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Zheng, Huilan, Gaurav Mirlekar e Lars O. Nord. "Machine learning techniques for modeling chemical absorption in CO2 capture process". In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192011.

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Post-combustion carbon capture (PCC) technologies play an important role in the reduction of CO2 emissions to address climate challenges. This process is usually simulated in process simulation software based on first-principle models, which calculate physical properties directly from basic physical quantities such as mass and temperature. Using first-principle models usually requires a long computation time, which makes optimization and control difficult. In this study, machine learning algorithms, such as eXtreme Gradient Boosting (XGBoost) and Support Vector Regression (SVR), are investigated as potential alternative modeling approaches. XGBoost is an ensemble algorithm that is based on the decision tree and optimized by gradient boosting. SVR fits the best line within a predefined or threshold error value. These two algorithms are used to build models to predict the CO2 capture rate (CR) and specific reboiler duty (SRD) in a monoethanolamine-based PCC process. By using the XGBoost, the verification result shows R2 (a statistical measure that represents the fitness of the model) in predicting CR is 91.7% and in predicting SRD is 80.8%, while by using SVR the R2 in predicting CR and SRD is 87.9% and 87.2% individually. In addition, XGBoost and SVR take 0.022 seconds and 0.317 seconds respectively to predict CR and SRD of 1318 cases, while the first-principal process simulation model needs 3.15 seconds to calculate 1 case. The data-driven models built using the XGBoost algorithm are employed for further optimization, which aims to find an operating point to have a higher CR and lower SRD. Particle swarm optimization (PSO), a stochastic optimization technique based on the movement and intelligence of swarms, is implemented for the optimization. The CR and SRD for optimal operating conditions are 72.2% and 4.3 MJ/kg each. The computations are faster with the data-driven models incorporated in the optimization technique. Thus, the application of machine learning techniques in carbon capture technologies is demonstrated successfully.

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Yu, Jirong, Mulugeta Petros, Yingxin Bai, Songsheng Chen, Jason Lu e Upendra Singh. "A Pulsed 2-micron Coherent Differential Absorption Lidar for Atmospheric CO2 Measurements". In Laser Applications to Chemical, Security and Environmental Analysis. Washington, D.C.: OSA, 2012. http://dx.doi.org/10.1364/lacsea.2012.lt5b.1.

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Schulz, Christof, Joachim Gronki, Jon D. Koch, David F. Davidson, Jay B. Jeffries e Ronald K. Hanson. "Temperature-dependent absorption by CO2: implications for UV diagnostics in high-temperature flames". In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: OSA, 2002. http://dx.doi.org/10.1364/lacea.2002.fc2.

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Al Hadhrami, Maitha Zuhair, Mohammad Abdel Fattah Alalaween, Antonio Lugay Mateo, Abdulmajeed Abdulla Al Blooshi, Khalid Yousuf Kahoor, Saeed Ali Al Yileili e Rashid Salem Al Suwaidi. "Factors Affecting CO2 Absorption in Water Using a Gas Absorption Packed Column". In Gas & Oil Technology Showcase and Conference. SPE, 2023. http://dx.doi.org/10.2118/214122-ms.

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Abstract Population growth is directly associated with increase in energy demand. Amplification in industrial activity has led to a drastic escalation in greenhouse gas emissions causing global warming. The major gas involves carbon dioxide, accounting for 76% emitted from different industrial sectors. The oil and gas industry alone is responsible for 90% of these emissions. Removing CO2 is a vital process in the gas industry which must be undertaken. Carbon capture utilization and storage (CCUS) technologies have evolved through the years due to the necessity of the current world-wide shared goal, to attain net zero. Several combustion methods have been developed to capture CO2 during actual operations at fossil fuel power plants, at natural gas processing plants and at coal gasification plants. However, methods that are based on chemical and physical absorptions have been most widely used. One example is the gas absorption-based method which requires low energy consumption and has been proven to be cost-effective. Using certain water types, mixed with minute concentration of chemical solvent, it can readily absorb CO2. This approach will be used in the following research study to investigate gas absorption rate using different water samples that pass through a packed column, thereby enhancing the mass transfer of gas component. In this study, the gas absorption experiments were carried out using SOLTEQ gas absorption unit containing DN 80 packed column with glass Raschig rings and with an effective column height of 1000 mm (Figure 1). Under constant operating conditions, the temperature and pressure were set to 24°C and 2 bars, respectively, to investigate the impact of pH level and conductivity of various types of water on CO2 absorption at different gas flow rate. The statistical analysis indicates that TDS and conductivity have a stronger correlation with gas absorption (P=0.99) than pH (P=0.76). The average CO2 absorption of the three samples at different flow rates (e.g., 0.8, 1.3, and 2.2 LPM) ranged from 36.40 in sample 1 to 69.50 in sample 2 at flow rate 2.2 LPM. Overall, samples 2 and 3, neutral to base with pH value of 7.25 and 8, respectively, have a statistically significant negative correlation with average CO2 absorption, whereas the acidic (pH = 5.42) sample 1 has significant positive correlation between the two variables (R2 = 0.99). Overall, samples 2 and 3, which are neutral to base with pH values of 7.25 and 8, have a statistically significant negative correlation with average CO2 absorption. In contrast, the acidic (pH = 5.42) sample 1 has a significant positive correlation between the two variables (R2= 0.99). This study provides optimal operating conditions for the CO2 absorption process. However, additional research is required to investigate the effect of other physical and chemical properties of water on CO2 absorption.

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Relatórios de organizações sobre o assunto "CO2 chemical absorption"

Committee on Toxicology. COT FSA PBPK for Regulators Workshop Report 2021. Food Standards Agency, abril de 2024. http://dx.doi.org/10.46756/sci.fsa.tyy821.

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The future of food safety assessment in the UK depends on the Food Standards Agency’s (FSA) adaptability and flexibility in responding to and adopting the accelerating developments in science and technology. The Tox21 approach is an example of one recent advancement in the development of alternative toxicity testing approaches and computer modelling strategies for the evaluation of hazard and exposure (New Approach Methodologies (NAMs). A key aspect is the ability to link active concentrations in vitro to likely concentrations in vivo, for which physiologically based pharmacokinetic (PBPK) modelling is ideally suited. The UK FSA and the Committee on Toxicity of Chemicals in Food, Consumer Products, and the Environment (COT) held an “PBPK for Regulators” workshop with multidisciplinary participation, involving delegates from regulatory agencies, government bodies, academics, and industry. The workshop provided a platform to enable expert discussions on the application of PBPK to health risk assessment in a regulatory context. Presentations covered current application of PBPK modelling in the agrochemical industry for in vitro to in vivo extrapolation (IVIVE), pharmaceutical industry for drug absorption related issues (e.g., the effect of food on drug absorption) and drug-drug interaction studies, as well as dose extrapolations to special populations (e.g., those with a specific disease state, paediatric/geriatric age groups, and different ethnicities), environmental chemical risk assessment, an overview of the current regulatory guidance and a PBPK model run-through. This enabled attendees to consider the wide potential and fitness for purpose of the application of PBPK modelling in these fields. Attendees considered applicability in the context of future food safety assessment for refining exposure assessments of chemicals with narrow margins of exposure and/or to fill data gaps from more traditional approaches (i.e., data from animal testing). The overall conclusions from the workshop were as follows: PBPK modelling tools were applicable in the areas of use covered, and that expertise was available (though it is in small numbers). PBPK modelling offers opportunities to address questions for compounds that are otherwise not possible (e.g., considerations of human variability in kinetics) and allows identification of “at risk” subpopulations. The use of PBPK modelling tends to be applied on a case-by-case basis and there appears to be a barrier to widespread acceptance amongst regulatory bodies due to the lack of available in-house expertise (apart from some medical and environmental agencies such as the European Medicines Agency, United States Food and Drug Administration, and the US Environmental Protection Agency, respectively). Familiarisation and further training opportunities on the application of PBPK modelling using real world case studies would help in generating interest and developing more experts in the field, as well as furthering acceptance. In a regulatory context, establishing fitness for purpose for the use of PBPK models requires transparent discussion between regulatory agencies, government bodies, academics, and industry and the development of a harmonised guidance such as by the Organisation for Economic Co-operation and Development (OECD) would provide a starting point. Finally, PBPK modelling is part of the wider “new approach methodologies” for risk assessment, and there should be particular emphasis in modelling both toxicodynamics and toxicokinetics.

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Campobasso, Marissa, Musa Ibrahim, Amanda Chisholm, Julia Miazek e Martin Page. pH pivoting for algae coagulation : bench-scale experimentation. Engineer Research and Development Center (U.S.), maio de 2024. http://dx.doi.org/10.21079/11681/48611.

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Harmful algal blooms (HABs) threaten recreational waters and public supplies across the US, causing detrimental economic and environmental effects to communities. HABs can be mitigated with dissolved air flotation (DAF) treatment, which requires addition of pH-sensitive charged chemicals to neutralize algae, allowing them to attach to microbubbles and float to the surface. During HAB events and photosynthesis, algae raise the pH to levels that are not ideal for DAF. Traditionally, pH is reduced with a strong acid; however, this adds operational cost and permanently adjusts the water’s pH. This study assessed an approach that might allow for infusing CO₂ from diesel-powered electricity generators into the water prior to DAF treatment. It was hypothesized that formation of carbonic acid could temporarily reduce the pH. Results showed that 2.5%–5.0% CO₂ mixed within compressed air can achieve pH levels between 6–7 in algal water with an initial pH of 9–11 and alkalinity of 150 mg/L as CaCO₃. Further, dosing CO₂ before chemical addition yielded a 31% improvement in water clarification. Returning the pH back to natural levels was not achieved using ambient air microbubbles; however, coarse bubble air spargers should be tested to provide more volumetric capacity for CO₂ absorption.

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