Relevant bibliographies by topics / Gas Absorption in Liquids / Dissertations / Theses
To see the other types of publications on this topic, follow the link: Gas Absorption in Liquids.

Dissertations / Theses on the topic 'Gas Absorption in Liquids'

Author: Grafiati
Published: 4 June 2021
Last updated: 12 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Gas Absorption in Liquids.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Yan, Xueru. "Development of a hybrid process, Membrane-Ionic Liquid (ILM), for gas treatment Ionic liquids combined wtih membrane separation processes : A review." Thesis, Ecole centrale de Marseille, 2020. http://www.theses.fr/2020ECDM0009.

Full text
Abstract:
L'élimination des polluants d'un mélange gazeux est un enjeu majeur en termes de réduction de l'impact environnemental de nombreux procédés industriels. Les liquides ioniques sont des solvants de remplacement prometteurs pour les composés organiques traditionnels utilisés dans la séparation sélective en raison de leur pression de vapeur négligeable et de leurs propriétés chimico-physiques concevables. Dans cette étude, un nouveau concept, la combinaison des IL et d'une membrane céramique tubulaire (ILM), a été développé dans le but de séparer les gaz ou les liquides des flux d'alimentation. Par rapport aux procédés classiques d'élimination des gaz ou des liquides, les ILM offrent une grande stabilité et une résistance mécanique élevée pendant une longue période de fonctionnement. Dans le cas des traitements de gaz, l'élimination de l'humidité pour protéger le capteur de gaz et le traitement du gaz industriel contenant du toluène sont les deux parties développées dans ce manuscrit. Les effets de plusieurs paramètres de fonctionnement, notamment le débit de gaz, la température, la pression, la concentration d'alimentation, la surface effective de la membrane (longueur de la membrane de support) et la position des canaux de gaz, ont été étudiés à la fois sur l'élimination de l'humidité et du toluène (vapeur). En outre, un modèle mathématique en deux étapes a été utilisé pour simuler les résultats expérimentaux et évaluer la performance de séparation des MIL dans les conditions de fonctionnement proposées. Selon les résultats expérimentaux et simulés, les ILM présentaient une capacité d'absorption relativement élevée de l'humidité et du toluène. Ce nouveau procédé ILM sera le procédé vert dominant pour la séparation des polluants gazeux ou liquides
The removal of pollutants from a gas mixture is a major issue in terms of minimizing the environment impact of numerous industrial processes. Ionic liquids are promising alternative solvents for traditional organic compounds using in selective separation due to their negligible vapor pressure and designable chemic-physical properties. In this study, a new concept, combination of ILs and a tubular ceramic membrane (ILM), has been developed with the aim of gas or liquid separation from feed streams. Comparing to conventional gas or liquid removal processes, ILMs provide high stability and mechanical resistance during long-time operation. Moreover, specific properties of ILs ensure selectivity and absorption capacity of ILMs. In the case of gas treatments, removal of humidity to protect gas sensor and treatment of industrial gas containing toluene are the two parts developed in this manuscript. Effects of several operating parameters, including gas flow rate, temperature, pressure, feed concentration, effective surface area of membrane (length of the support membrane) and position of gas channels, were investigated both on humidity and toluene (vapor) removal. In addition, a two-step model was used to simulate experimental results and evaluate the separation performance of ILMs. According to both experimental and simulated results, ILMs exhibited relative high absorption capacity of humidity and toluene. This new ILM process will be the dominating green processes for gas or liquid pollutants separation
APA, Harvard, Vancouver, ISO, and other styles
2

Cooke, Jason. "Modelling of reactive absorption in gas-liquid flows on structured packing." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/397079/.

Full text
Abstract:
Carbon capture & storage (CCS) is at the technological forefront in the challenge of reducing carbon emissions. The most viable approach to implementing CCS within existing coal and natural gas power stations is the post-combustion capture of CO2 by absorption into amine solutions within packed column absorbers. CFD modelling is an important aspect in the design and optimisation of this process. However, significant challenges arise due to the large range of spatial scales and the complexity of the physics being modelled. Therefore, simplification of the problem is required to complete such simulations using the computational resources currently available. This thesis explores some of the approaches used to model flow within packed columns. It concludes that, with current computing resources, standard modelling approaches are not viable for large scale simulations of CCS. This led to the development of the Enhanced Surface Film (ESF) model. The ESF approach was able to simulate chemically enhanced absorption of gaseous species into thin liquid films. The method significantly reduced the computational resources required and is a significant step to enable future researchers to model larger domains in CCS. The ESF approach has wide ranging applications due to the ubiquitous nature of liquid films across the industrial and environmental sectors. In many industries the dynamics of thin liquid films play a crucial role in the overall performance. Further applications may include thin film microreactors, surface coating, biofluids and medical applications.
APA, Harvard, Vancouver, ISO, and other styles
3

Zea, Luis. "EXPERIMENTAL ANALYSIS OF THE HYDROGEN SULFIDE ABSORTION PHENOMENA IN BRINE/OIL MIXTURES AS A FUNCTION OF SYSTEM PRESSURE AND H2S." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3053.

Full text
Abstract:
In underground oil reservoirs, Hydrogen sulfide is usually found coexisting with the oil due to bacteria reduction over a long period of time. The amount of H2S in the oil varies from place to place around the globe. When the oil extraction process begins, the presence of Hydrogen sulfide becomes noticeable as drilling tools, piping and other equipment suffer from sulfide stress cracking, electrochemical corrosion and corrosion fatigue. For this reason, the oil industry invests millions of dollars per year trying to find better ways to reduce the amount of H2S in oil. An important part of the current investigations deals with brine (sea water)/oil mixtures. The reasons are two-fold: 1) one way of extracting the petroleum from the reservoir is by injecting brine into it and since it has a higher density than oil, the latter will be ejected up to the surface. Taking into account the complex fluid flow occurring within the reservoir it is easy to understand that some brine will also be present as part of the ejected fluid; 2) brine is already present in the reservoir, so independent of the extraction method used, there will be a brine/oil mixture in the ejected flow. When brine and oil have absorbed H2S under pressure in the reservoir and then suffer a decompression during the extraction process, a certain amount of H2S is released from the liquid phase. In order to have a better prediction of how much Hydrogen sulfide can be liberated a good understanding of H2S absorption by these liquids is necessary. The amount of gas a solvent absorbs is a function of pressure, original gas concentration and temperature as described by Henry's Law. The purpose of this thesis is to experimentally analyze how much of the corrosive gas is absorbed into different brine/oil mixtures, and brine and oil, separately. In order to find sufficient data for a thorough analysis, different reservoir simulation scenarios were created. The liquids were mixed from pure brine to pure oil, resulting in 33% and 66% water cuts. Data were obtained at 2 pressures of 20atm and 70atm at room temperature. H2S concentration was also a variable, changing the original gas concentration through different values: 50, 100, and 300ppm. These experiments were conducted in an autoclave system and will better explain the hydrostatic process that occurs inside the reservoir. It was found that throughout all the water cuts, the role that total pressure plays in the absorption phenomena is of less importance as the original H2S concentration is increased. In the same manner it was observed that the highest mass-absorption ratios are always found between 50 and 100ppm and the lowest at 300ppm, this is observed for all water cuts and total pressures. Another important finding was that the ability to absorb the corrosive gas decreases as the original H2S concentration increases and this proves to be true for all water cuts and system pressures. After conducting these different reservoir scenarios, tests were conducted to simulate 300m of the horizontal section of the pipe that connects the head of the well with the platform. This was done with a high pressure 300-meter long loop. It was found that the corrosive gas is absorbed at a higher rate when there is a flow, opposite to a hydrostatic case. Henry's Law constant was identified for each water cut and each pressure, however, the test procedure could not be validated since the gas being studied was not in its pure form. Understanding the absorption phenomena of Hydrogen sulfide in different water cuts will definitely be of great help to the oil industry to make better forecasts of H2S concentrations being ejected from each well.
M.S.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Aerospace Engineering MSAE
APA, Harvard, Vancouver, ISO, and other styles
4

Nicholls, M. P. "Development and performance characterisation of a novel gas-liquid contacting stage." Thesis, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313507.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Shalygin, Maxim. "Réalisation et caractérisation du transport sélectif gazeux de contacteurs gaz-liquide à membrane (Selective transport of gases in gas-liquid membrane system)." Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL022N/document.

Full text
Abstract:
Ce travail rapporte l’étude de systèmes membranaires à valves sélectives (SMV), qui combinent les avantages des techniques de séparation par membrane et par absorption. La 1ère partie du mémoire présente l'étude du transport de matière en régime permanent et transitoire dans les SMV élaborés à partir de membranes polymères denses et de solution aqueuses. Dans la 2ème partie le développement d'un modèle mathématique original pour la simulation des SMV est proposé ainsi que son évaluation expérimentale pour les séparations CO2/CH4/H2, avec des solutions aqueuses confinées de K2CO3. Des améliorations simultanées de la perméabilité (˜ 4 fois) et de la sélectivité (>20 fois) ont été obtenues pour CO2 avec le mélange CO2/H2. Un logiciel basé sur un nouveau modèle de transport de gaz dans ces contacteurs membranaires prenant en compte la sorption physique et chimique dans la phase liquide a été développé pour le calcul de la perméabilité en régime transitoire ou permanent
Combined gas-liquid membrane systems gather the advantages of membrane and absorption separation techniques. Specifically, selective membrane valves (SMV called flowing liquid membranes) were studied, i.e. creation, gas transport experiments, liquid nature and temperature dependences, and modelling. SMV use a flowing layer of liquid supported between two membranes. The 1st part of the dissertation reports the study of steady and non-steady state gas transports in SMV built out dense polymeric membranes. In the 2nd part is given the development of an original mathematical model for SMV simulation and its experimental assessment for CO2/CH4/H2 mixtures with aqueous solutions of K2CO3. From systematic studies of steady and non-steady state processes, both in flow-through and circulating modes, it was found that increasing of temperature and liquid carrier concentration (K2CO3) leads to the simultaneous rise of permeability and selectivity during CO2 recovery from CO2/H2 mixture
APA, Harvard, Vancouver, ISO, and other styles
6

Moura, Leila. "Liquides ioniques pour la séparation des d'hydrocarbures gazeux." Phd thesis, Université Claude Bernard - Lyon I, 2014. http://tel.archives-ouvertes.fr/tel-01064777.

Full text
Abstract:
L'objectif de ces travaux était de synthétiser, caractériser et étudier le potentiel d'une sélection de liquides ioniques, pour la séparation de l'éthane et de l'éthène. L'influence dans l'absorption de l'éthène de la présence de trois cations métalliques, le lithium (I), le nickel (II) et le cuivre (II) dans un liquide ionique était également étudiée. Les liquides ioniques sélectionnés sont basés sur le cation imidazolium contenant des groupes fonctionnels au niveau de la chaine alkyle latérale. Les anions choisis sont le bis(trifluorométhylsulfonyl)imide, [NTf2], la dicyanamide, [DCA] et le méthylphosphite, [C1HPO3]. Sachant qu'un solvant de séparation idéale doit avoir une capacité d'absorption et une sélectivité de séparation élevées, une faible viscosité, une haute stabilité thermique et une cinétique d'absorption rapide pour le gaz sélectionné. Pour évaluer ces propriétés pour les milieux sélectionnés, plusieurs paramètres ont été déterminés la densité et la viscosité des liquides ioniques ainsi que l'absorption de chaque gaz dans les liquides ioniques. L'absorption de l'éthane et de l'éthène dans les liquides ioniques purs ainsi que dans les solutions de liquide ionique + sel métallique a été mesurée dans une gamme de températures comprises entre 303.15 K et 353.15 K et pour des pressions proches de l'atmosphérique. La sélectivité idéale des liquides ioniques pour l'absorption de l'éthane par rapport à l'éthène a ainsi pu être déterminée. La détermination de l'absorption en fonction de la température a permis d'accéder aux propriétés thermodynamiques de solvatation de ces gaz dans des liquides ioniques et à comprendre la manière dont les liquides ioniques interagissent avec ces solutés comment les liquides ioniques se structurent autour de ces molécules
APA, Harvard, Vancouver, ISO, and other styles
7

Zhang, Chengda. "SYNTHESES OF PEG/ALKYL-BASED IMIDAZOLIUM/PYRIDINIUM IONIC LIQUIDS AND APPLICATIONS ON H2S ABSORPTION& SYNTHESES OF POLYSULFONE BASED FUNCTIONALIZED IMIDAZOLIUM IONIC POLYMERS AND APPLICATIONS ON GAS SEPARATION." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1797.

Full text
Abstract:
The synthesis method for PEG/alkyl-based imidazolium/pyridinium ionic liquids was studied. Four steps were used to fabricate the membranes: polymerization, chloromethylation, linkage of the polymers with the pendent groups and membrane cast. Permeabilities and CO2/N2 selectivity of two membranes were examined and each showed remarkable CO2/N2 selectivity. CO2 permeability of the [PSM-MIM][Cl] membrane is better than that of the [PSM-MEIM][Cl] membrane, which is due to the steric hindrance of the methoxyethyl group. The syntheses of PEG/alkyl-based imidazolium/pyridinium ionic liquids (IL) were studied. PEG-based ILs were demonstrated to have better H2S solubilities than the alkyl-based ILs. H2S solubilities of the imidazolium ILs and pyridinium ILs were compared. The anion effects on H2S solubilities have been investigated, while the temperature effects on H2S solubilities will need to be studied in the near future.
APA, Harvard, Vancouver, ISO, and other styles
8

Mhiri, Neïla. "Étude d'un procédé propre couplant l'absorption gaz/liquide microstructurée avec la distillation pour le traitement d'air chargé par un Composé Organique Volatil." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL030N/document.

Full text
Abstract:
Cette thèse porte sur le développement d’un procédé industriel propre constitué par un couplage absorption-distillation, destiné aux traitements d’effluents gazeux chargés par un Composé Organique Volatil (COV). L’absorption est effectuée dans un microabsorbeur à film tombant. La première étape de ce travail consiste à caractériser le transfert de matière dans cet appareil, lors de l’absorption gaz/liquide du Perchloroéthylène (PCE) par le Di(2-EthylHexyl)Adipate (DEHA). Les expériences ont montré la faisabilité et l’intérêt de cette opération dans un micro-contacteur. En effet, les efficacités d’épuration obtenues sont comparables à celles des procédés classiques (jusqu’à 97%) et les quantités de solvant d’absorption utilisées sont très faibles. Une étude paramétrique a révélé une intensification significative du transfert de matière, côté gaz, et un gain en compacité, à la suite de la minimisation de l’épaisseur de la veine de gaz (2mm) et du débit de la phase gazeuse. Cette étude a également montré la limite du microabsorbeur à traiter de grands débits de gaz avec de bonnes efficacités, causée par la faible influence qu’exerce la vitesse du gaz sur le coefficient de transfert de matière. Ce comportement a été expliqué, grâce à des simulations en 2D, par une dispersion importante des profils de concentration indiquant une limitation diffusionnelle. Cette dernière provient essentiellement du régime laminaire lisse et de la petite taille caractérisant ce type de micro-procédé. Pour s’affranchir de cette limitation, la turbulence doit être favorisée dans le gaz. La deuxième étape de ce travail concerne l’extrapolation du microabsorbeur de laboratoire à l’échelle industrielle des PME/PMI, basée sur le concept du numbering-up. A l’issu des calculs, un absorbeur microstructuré efficace (95%), et compact (surface occupée ˜ 0,5m2) a été développé. Pour rentabiliser son fonctionnement, un recyclage par distillation flash du solvant d’absorption a été étudié. Les résultats obtenus ouvrent la voie sur une technique d’épuration prometteuse, qui nécessite néanmoins une validation théorique et expérimentale du couplage absorbeur-distillateur
This project focuses on the development of an industrial process, in which a coupled absorption/distillation unit is developed to treat gaseous effluents contaminated by a Volatile Organic Compound (VOC). Absorption is performed in a falling film microabsorber. The first stage of this work consists in characterizing the mass transfer in this device. The gas/liquid absorption of Perchloroethylene (PCE) by Di (2-EthylHexyl) Adipate (DEHA) is used as test case. Experiments showed the feasibility and the benefit of this separation process operated in a micro-contactor. Indeed, the purification efficiencies obtained are comparable to those of conventional processes (97%). Moreover, the required absorption solvent quantities are very low. A parametric study revealed significant mass transfer intensification on gas side and a gain in compactness due to the minimization of gas cavity thickness (2mm) and gas flowrate. This study also showed the limits of microabsorbers to handle large gas flowrates with good efficiencies, due to a low influence of gas velocity on the mass transfer coefficient. This behaviour was explained, thanks to 2D simulations, by a significant dispersion of concentration profiles, which indicates a diffusion limitation. The latter comes mainly from smooth laminar flow and the small size, a typical characteristic of micro-processes. To overcome this limitation, turbulence should be promoted in the gas. The second stage of this work concerns the microabsorber extrapolation from laboratory scale to industrial SMEs, based on the numbering-up concept. Calculations predict high throughputs with a microstructured absorber of competitive efficiency (95%) and high compactness (area occupied ˜ 0.5 m2). For profitable operation, solvent absorption recycling by a flash distillation is studied. The results lead to a promising treatment technique, which still requires a theoretical and experimental validation of the coupled absorber-distiller unit
APA, Harvard, Vancouver, ISO, and other styles
9

Kundu, Arunabha. "Tree phase reactors : A, Hydrodynamics and partial wetting of trickle beds : B, absorption enhancement in gas-liquid-liquid bublle column." Toulouse, INPT, 2004. http://www.theses.fr/2004INPT003G.

Full text
Abstract:
Two investigations on three phase reactors are reported : liquid flow maldistribution and partial wetting of the catalyst in trickle bed reactors, and effects of adding small amounts of organic phase on gas to aqueous phase mass transfer in a bubble column. Radial distribution of the liquid flow is investigated in a 0. 152 m in diameter fixed bed of 5 successive catalysts of various shape and size, and various trickling liquids (water, water+additives, kerosene). A model has been derived based on force balance on each fluid phase and compared to experimental results including previous works. This model was extended to partial wetting, characterised by tracer analysis. In bubble column, oxygen to water mass transer was shown to be highly influenced by adding only 1% oil fraction. 7 organic liquids were used showing more than 300% mass transfer enhancement with alkanes and conversely 50% reduction with more water soluble components, these effects being mainly relatde to bubble size.
APA, Harvard, Vancouver, ISO, and other styles
10

Grima, N. M. M. "Kinetic and mass transfer studies of ozone degradation of organics in liquid/gas-ozone and liquid/solid-ozone systems." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3351.

Full text
Abstract:
This work was concerned with the determination of mass transfer and kinetic parameters of ozone reactions with four organic compounds from different families, namely reactive dye RO16, triclocarban, naphthalene and methanol. In order to understand the mechanisms of ozone reactions with the organic pollutants, a radical scavenger (t-butanol) was used and the pH was varied from 2 to 9. Ozone solubility (CAL*) is an important parameter that affects both mass transfer rates and chemical reaction kinetics. In order to determine accurate values of the CAL* in the current work, a set of experiments were devised and a correlation between CAL* and the gas phase ozone concentration of the form CAL*(mol/L) = 0.0456 CO3 (g/m3 NTP) was obtained at 20°C. This work has also revealed that t-butanol did not only inhibit hydroxyl radical reactions but also increased mass transfer due to it increasing the specific surface area (aL). Values of the aL were determined to be 2.7 and 3.5 m2/m3 in the absence and presence of t-butanol respectively. It was noticed that the volumetric mass transfer coefficient (kLa) has increased following the addition of t-butanol. Ozone decomposition was studied at pH values of 2 to 9 in a 500 mL reactor initially saturated with ozone. Ozone decomposition was found to follow a second order reaction at pH values less than 7 whilst it was first order at pH 9. When the t-butanol was added, the decomposition of ozone progressed at a lower reaction order of 1.5 for pH values less than 7 and at the same order without t-butanol at pH 9. Ozone decomposition was found significant at high pHs due to high hydroxide ion concentration, which promotes ozone decomposition at high pHs. The reaction rate constant (k) of RO16 ozonation in the absence of t-butanol was determined. The result suggests that RO16 degradation occurs solely by molecular ozone and indirect reactions by radicals are insignificant. The chemical reaction of triclocarban with ozone was found to follow second order reaction kinetics. The degradation of naphthalene using the liquid/gas-ozone (LGO) system was studied. This result showed that hydroxyl radicals seemed to have limited effect on naphthalene degradation which was also observed when a radical scavenger (t-butanol) was used. Reaction rate constants were calculated and were found around 100 times higher than values reported in the literature due to differences in experimental conditions. From the results of the experimental investigation on the degradation of methanol by ozone it was found that the rate constant (k) of the degradation reaction increased at pH 9. The reaction stoichiometry was found to have a value of 1 mol/mol. The two steps of the liquid/solid-ozone (LSO) system were studied on beds of silica gel and a zeolitic material (D915) and the ozone adsorption process was modeled and found that particle rate controls ozone adsorption step but liquid rate controls the water treatment step. Ozone desorption with pure deionised water was studied. The water flow rate was found to accelerate the desorption rates but pH was found to decrease the desorption rates. In contrast, the effect of pH was insignificant in the presence of t-butanol. Determination of the adsorption isotherms for RO16, naphthalene and methanol revealed that RO16 did not exhibit adsorption on silica gel, but both naphthalene and methanol showed adsorption on D915 described by Langmuir model.
APA, Harvard, Vancouver, ISO, and other styles
11

Kalivoda, Josef. "Odstraňování plynných polutantů ze vzdušnin na poloprovozní pračce." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-369741.

Full text
Abstract:
The PHD thesis is focused on the absorption with chemical reaction on the pilot plant gas/liquid scrubber. The performance characterization of the apparatus is based on the absorption of carbon dioxide in to the 1\% sodium hydroxide sollution and includes pressure drops, liquid holdup, gas/liquid contact time and the capture effectiveness as well. The experimantal part of the thesis includes a complex of mathematical equations based on the Film theory. The complex of the mathematical equations allowed a calculation of the overall mass transfer coefficient for the type of the gas scrubber at the given experimental conditions.
APA, Harvard, Vancouver, ISO, and other styles
12

Fougerit, Valentin. "Développement d’un procédé innovant d’épuration du biogaz par mise en oeuvre de contacteurs à membranes." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC053/document.

Full text
Abstract:
L’épuration est une solution attractive pour la valorisation du biogaz. Néanmoins, les coûts associés à ces procédés constituent un frein au développement, en particulier pour l’épuration du biogaz d’origine agricole.Ces travaux ont évalué le contacteur à membranes, technologie issue du poumon artificiel, pour le développement d’un procédé d’absorption physique, robuste et répondant aux exigences de la filière. Un pilote expérimental modulaire (150-880 NL/h biogaz) a permis d’investiguer les performances du procédé en termes de rendement méthane R_CH4 et de qualité méthane y_CH4,out.Le contacteur à membranes permet de produire un biométhane répondant aux spécifications de l’injection réseau. Les paramètres opératoires clés ont été mis en évidence par un plan d’expérience. Parmi les limites connues du procédé, l’effet de l’humidification de la membrane sur le débit d’absorption du CO2 reste limité (< 10.5%) : une nouvelle description de l’humidification des pores a été proposée. La composition du gaz est plus limitante : le coefficient de transfert du CO2 est divisé par un facteur 2-3 lorsque celui-ci est présent en mélange plutôt qu’en gaz pur. Plusieurs configurations et solvants ont été testés pour améliorer les performances. L’intégration d’une boucle de recyclage et le remplacement de l’eau par une solution de sels (KCl) ont permis de déployer un procédé breveté atteignant les performances visées (R_CH4=98.7%, y_CH4,out=97.5%) : le flux membranaire est de 42 NL/m2/h CO2.En vue d’un dimensionnement industriel, un modèle original de transfert a été développé pour intégrer la géométrie interne spécifique du module membranaire. Optimisé et validé pour l’absorption de CO2 pur, cet outil numérique a nécessité l’optimisation d’une correction additionnelle inspirée des lois de diffusion pour décrire la limite observée en présence d’un mélange de gaz.Une mise à l’échelle est proposée pour 3 unités industrielles (100, 250 et 500 Nm3/h biogaz) sur la base des équipements disponibles. Les dimensionnements obtenus par analyse dimensionnelle ou par modélisation numérique diffèrent de 25 à 40 % et doivent encore être validés
Upgrading is an attractive pathway for biogas utilization. Yet, the costs associated to these processes are still an obstacle to a widespread development, specifically in the case of farm anaerobic digestion units.This PhD has assessed membrane contactor, a technology derived from the artificial lung, for the development of a robust gas-liquid physical absorption process meeting the biogas industry expectations. A modular experimental pilot (150-880 NL/h biogas) was designed to investigate the performances in terms of methane recovery R_CH4 and methane quality y_CH4,out.The membrane contactor technology turned out to be suitable to produce a gas-grid quality biomethane. Key operating parameters were identified through a Design of Experiments. Among known process limitations, membrane wetting was found to have little influence on CO2 absorption (< 10.5%): a new pore wetting description was suggested. Gas composition was a stronger limitation: the CO2 mass transfer coefficient was divided by a factor 2-3 in the presence of a gas mixture instead of as a pure gas.Process configurations and solvents were successively tested to improve the performances. The addition of a methane recycling loop and the replacement of water by a saline solution (KCl) were combined into a patent and reached the targeted performances (R_CH4=98.7%, y_CH4,out=97.5%): the corresponding absorbed flux is 42 NL/m2/h CO2.For a process upscaling purpose, an original mass transfer model was developed to describe the specific internal geometry of the membrane module. Firstly optimized and validated for the absorption of pure CO2, this numerical tool has required an optimized additional correction inspired from diffusion laws to account for the mass transfer limitation observed for a binary gas mixture.Process designs are suggested for 3 industrial cases (100, 250 and 500 Nm3/h biogas) based on an available membrane contactor range. The process sizings resulting from the dimensional analysis methodology or numerical simulation differ from 25 to 40 % and must then be confirmed
APA, Harvard, Vancouver, ISO, and other styles
13

Dianne, Soule Melissa C. Kido. "Nonlinear vibrational spectroscopic studies of the absorption and orientation of environmentally important molecules at the vapor/water interface /." view abstract or download file of text, 2007. http://proquest.umi.com/pqdweb?did=1335361671&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.

Full text
Abstract:
Thesis (Ph. D.)--University of Oregon, 2007.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 146-156). Also available for download via the World Wide Web; free to University of Oregon users.
APA, Harvard, Vancouver, ISO, and other styles
14

Myrillas, Konstantinos. "Experimental and numerical investigation of gas jet and liquid film interaction." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209848.

Full text
Abstract:
The topic of this thesis is the interaction between gas jet flow and a liquid film dragged by a solid substrate. This method, known as jet-wiping, is used in several industrial processes. Hot-dip galvanization of steel strips is an important application, where jet wiping is used to control the thickness of the liquid zinc that is applied on a continuous steel substrate. Unsteady phenomena in the process lead to the creation of waves on the liquid film, which is known as undulation. This unwanted phenomenon deteriorates the quality of the final product.

The aim of the current study is to identify the causes of the undulation and propose possible solutions to tackle the problem. This is achieved through studying the hydrodynamic interaction between the gas jet flow and the liquid film. Experiments on a laboratory test facility and numerical simulations with 3 different Computational Fluid Dynamics (CFD) codes are employed for that purpose.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles
15

Nguyen, Phuc Tien. "Contacteurs à membranes denses pour les procédés d'absorption gaz-liquide intensifiés : application à la capture du CO₂ en post combustion." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL014N/document.

Full text
Abstract:
Dans le cadre de la recherche de procédés d'absorption gaz-liquide intensifiés, cette étude vise au développement des contacteurs membranaires pour la capture du CO₂ en post combustion, comparativement aux colonnes garnies. Les contacteurs à membranes fibres creuses microporeuses permettent un transfert de matière élevé mais sont confrontés à des problèmes de mouillage entraînant une dégradation importante des performances dans le temps. Notre but est de concevoir des fibres composites constituées d'une structure microporeuse et d'une peau dense fine et fortement perméable au CO₂ afin d'établir une barrière au passage du liquide et de limiter la résistance au transfert de matière. Pour cela, nous avons sélectionné des polymères super vitreux comme le PTMSP et le Téflon AF2400 qui se caractérisent par une très forte perméabilité au CO₂ et une bonne compatibilité chimique avec la MEA (liquide d'absorption de référence). Les fibres composites ont été réalisées par un procédé de recouvrement conduisant à une faible épaisseur de peau dense (1 à 2 microns). Des modules à fibres composites ont été testés pour séparer un mélange CO₂/N2 avec une solution aqueuse de MEA. Les fibres composites présentent des efficacités de capture similaires à celles des fibres microporeuses mais assurent en plus le maintien des conditions de non mouillage. Des simulations, reposant sur une modélisation 2D du transfert de matière, ont permis de prédire les performances des contacteurs membranaires à fibres composites dans des conditions plus proches de la réalité industrielle et ont mis en évidence un facteur d’intensification pouvant aller jusqu’à 6 par rapport aux colonnes garnies
The present work aims to explore the intensification of gas-liquid absorption processes. This study is applied to post combustion CO₂ capture by means of membrane contactors in comparison to packed columns. Microporous hollow fiber membrane contactors lead to high mass transfer but wetting problems are likely to occur and result in tremendous deterioration in performances with time. Our objective is to develop composite hollow fibers based on a microporous structure and a thin dense layer highly permeable to CO₂, in order to create a real barrier to liquid penetration and to limit mass transfer resistance. Super glassy polymers as PTMSP and Teflon AF2400 were selected for their extremely high CO₂ permeability and their chemical resistance to MEA (reference absorption liquid). Composite hollow fibers were made by coating and the dense layers obtained are thin (1 to 2 microns). Composite hollow fiber membrane contactors were tested for the separation of a CO₂/N2 mixture with an aqueous solution of MEA. Capture ratios achieved by composite hollow fibers are similar to those measured for microporous membranes and the dense layer prevents from wetting problems. Simulations based on 2D modeling of the mass transfer, show that the performances of composite hollow fiber membrane contactors, under operating conditions close to the industrial case, can lead to an intensification factor up to 6 compared to packed columns
APA, Harvard, Vancouver, ISO, and other styles
16

Ghasemian, Langeroudi Elahe. "Quantitative aspects of CO₂-grafted amine interactions in gas-liquid-solid solubility equilibrium : applications to CO₂ capture." Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/21467.

Full text
Abstract:
Les effets liés à la présence d'eau liquide sur la capacité d'adsorption de CO₂ par une silice mésoporeuse de type SBA-15 fonctionnalisée au moyen des amines suivantes: aminopropyltrimethoxysilane (APS) et N-(2-aminoéthyl) -3 - (aminopropyl) trimethoxysilane (AEAPS) ont été examinés pour évaluer le potentiel de ce mode de contact dans des laveurs gaz-liquide-solide. Les résultats ont été comparés à la capacité d'adsorption de CO₂ des amines greffées dans des conditions humides et sèches ainsi qu'à la capacité d'absorption de CO₂ dans les systèmes gaz-liquide avec des solutions aqueuses d'aminés ayant des structures semblables à celles des amines greffées. Dans ces conditions, une estimation de l'adsorption physique de CO₂ a été obtenue par l'étude de la SB A-15 non-modifiée. En outre, afin d'évaluer l'efficacité et la stabilité à long terme de l'association amine/SBA-15, les amines greffées ont été soumises à huit cycles successifs d'immersion dans les milieux aqueux d'une durée de 24 h chacune. Les échantillons récupérés ont été caractérisés au moyen de la diffraction aux rayons, des isothermes de sorption d'azote et d'analyse élémentaire CHN. Jusqu'à 40% de la quantité d'aminés greffées a subi une lixiviation durant les quelques premiers cycles de régénération; par la suite, la teneur en azote de l'AEAPS est demeurée relativement stable, contrairement à l'APS qui a connu une moindre stabilité. Fait intéressant, les structures des deux matériaux greffés, APS et AEAPS, sont demeurées intactes après plusieurs expositions à l'eau. L'efficacité de capture de CO₂ la plus élevée a été obtenue dans le cas des amines aqueuses (voie homogène). Cependant, la capture de CO₂ à l'aide d'aminés greffées dans le cas du système triphasique (gaz-liquide-solide) a donné lieu, pour des conditions opératoires comparables, à des valeurs intermédiaires entre les voies sèche et humide du mode de contact gaz-solide.
APA, Harvard, Vancouver, ISO, and other styles
17

Chery, Olivier. "Étude hydrodynamique et transfert de matière dans un contacteur gaz-liquide à film centrifuge dans le cadre de procédés de traitement d'effluents gazeux contenant du dioxyde de soufre et/ou des oxydes d'azote." Vandoeuvre-les-Nancy, INPL, 1994. http://docnum.univ-lorraine.fr/public/INPL_T_1994_CHERY_O.pdf.

Full text
Abstract:
Dans le cadre d'un programme B. R. I. T. E. De la C. C. E. , nous étudions un procédé de traitement d'effluents gazeux contenant du dioxyde de soufre et/ou des oxydes d'azote, par absorption suivie de l'oxydation de ces espèces. Dans une première phase, nous avons utilisé un contacteur gaz-liquide ayant des caractéristiques de transfert de matière élevées: le réacteur à film centrifuge. La caractérisation hydrodynamique du contacteur a permis de mettre en évidence les régimes de fonctionnement, le comportement, du réacteur piston au réacteur parfaitement agité, ainsi que les paramètres essentiels: la vitesse de rotation et la contre-pression. Nous avons ensuite déterminé les caractéristiques de transfert de matière de l'absorbeur par la mesure des coefficients volumiques de transfert de matière cote gaz et liquide. La dernière étape de cette étude a été une application du réacteur à film centrifuge à l'absorption d'un mélange dilué d'oxyde et de dioxyde d'azote dans une solution aqueuse d'urée. Il s'avère que les temps de séjour rencontrés dans le contacteur sont trop faibles pour que certaines réactions d'élimination de ces polluants puissent avoir lieu. La seconde partie a consisté à concevoir et à mettre en œuvre un réacteur à film tombant laminaire cylindrique, destiné à déterminer la cinétique de la réaction chimique suivant l'absorption du dioxyde de soufre dans une solution aqueuse acide de cérium quatre. Seules, quelques expériences ont pu être réalisées montrant que la réaction est probablement intermédiaire. D’autres expériences doivent également être menées afin de mieux caractériser ce réacteur
APA, Harvard, Vancouver, ISO, and other styles
18

Boucif, Noureddine. "Modélisation et simulation de contacteurs membranaires pour les procédés d'absorption de gaz acides par solvant chimique." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0280/document.

Full text
Abstract:
L'objectif primordial de cette thèse est la recherche de modèles mathématiques qui sont à mieux de décrire le processus d'absorption gaz-liquide dans un contacteur membranaire à fibres creuses poreuses ou denses. La configuration géométrique de ces contacteurs combinée à leur compacité, et de leur faible consommation d'énergie leur permet de se substituer progressivement aux procédés conventionnels tels les colonnes à garnissage et autres tours d'absorption. Notre but est d'étudier la performance de ces processus novateurs par l'élaboration de modèles mathématiques de plus en plus rigoureux. Pour cela, nous avons étudié plusieurs cas de figures où l'hydrodynamique d'écoulement des fluides, la nature du soluté et/ou du solvant ont été changées. Dans un premier temps, il n'a été tenu compte que de l'hydrodynamique du compartiment côté fibre pour deux types de processus d'absorption avec et sans réaction chimique. Par la suite, l'hydrodynamique d'écoulement des fluides dans le côté fibre comme côté calandre a été prise en considération. Des modèles ont été développés pour l'absorption classique de gaz carbonique dans des solutions de monoéthanolamine (liquide d'absorption de référence) où l'écoulement du fluide côté calandre est assimilé à un écoulement piston dans un premier cas, obéissant au modèle dit de surface libre "modèle de Happel" dans un deuxième cas, et enfin caractérisé par des équations de moments de Navier-Stokes dans un troisième cas. La comparaison des résultats numériques de ces modèles a montré que ceux du troisième cas de figure sont les plus proches des résultats d"essais expérimentaux
The overarching objective of this thesis is the research of mathematical models which are better to describe the process of gas-liquid absorption in a membrane contactor with porous or dense hollow fibers. The geometric configuration of these contactors, combined with their low energy consumption and their compactness, allows them to gradually replace conventional processes such as packing towers and absorption columns. Our goal is to study the performance of these innovative processes by developing more rigorous mathematical models. In this scope, we studied several cases where the hydrodynamics of fluid flow, the nature of the solute or solvent have been changed. First, only the hydrodynamics of the fibre side compartment has been taken into account for two types of an absorption process with and without chemical reaction. Subsequently, the hydrodynamics of fluid flow in both the fiber side as shell side were taken into consideration. Models have been developed for classical carbon dioxide absorption in monoéthanolamine solutions (liquid absorption of reference) where the flow fluid in the shell were is assumed to obey a plug-flow in a first case, described by the surface free model known as "Happel model" in a second case, and finally characterized by the momentum Navier-Stokes equations in a third case. The comparison of the numerically simulated results collected from the three models showed that those of the third case matched very closely with the laboratory experimental results
APA, Harvard, Vancouver, ISO, and other styles
19

Benizri, David. "Epuration du biogaz à la ferme : EPUROGAS, une solution énergétique et économique d'avenir. Etude expérimentale et modélisation d'un procédé d'absorption de dioxyde de carbone avec de l'eau sous pression à une échelle industrielle." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0024/document.

Full text
Abstract:
L’étude et la mise au point des procédés de traitement du biogaz représentent un défi majeur à relever pour accéder à une énergie propre produite à partir d’une unité de méthanisation. Le biogaz est un mélange de CH4 à 55% v/v et de CO2 à 40% v/v. La technique de l’absorption de CO2 par lavage à l’eau sous pression a été choisie dans cette thèse. L’optimisation, le contrôle et l’étude expérimentale de ce procédé, appelé EPUROGAS, ont été réalisés à l’échelle d’une ferme sur un prototype traitant un débit nominal de 40 Nm3/h. Deux axes de recherche ont été privilégié dans la mise au point de l’EPUROGAS : l’entraînement de méthane par l’eau et le recyclage de l’eau sans stripping pour permettre une valorisation simultanée du CH4 et du CO2 produits. Les principales innovations de ces travaux sont protégées par deux brevets : l’amélioration de la base de la colonne d’absorption et une méthode originale de désorption par mélangeur statique. Lors de ces travaux, une méthode statistique d’analyse des résultats expérimentaux a été proposée. Deux modèles prédictifs de génie des procédés ont été élaborés afin de prédire l’efficacité d’absorption du CO2 et le rendement de production de CH4. Un pilote complémentaire a été étudié : le SATUROMETRIX qui permet de caractériser des équilibres gaz/liquide entre plusieurs gaz et un liquide complexe sous pression, complétant les données bibliographiques des constantes de Henry associées aux mélanges complexes. Enfin, un système PSA qui conditionne le biogaz ou le méthane pré-épuré en Gaz Naturel Véhicule comprimé à 200 bar a été étudié. Les procédés EPUROGAS et PSA ont été couplés, évalués énergétiquement puis dans leur globalité par l’Analyse de Cycle de Vie
Biogas upgrading is a key technology for the renewable energy mix of tomorrow. Biogas is a mix of Carbon Dioxide (40%) and Methane (55%). It is obtained thanks to the anaerobic digestion of organic matter. The adapted High Pressure Water Scrubbing process was studied in this thesis. The process was installed in farm and operated at a real scale for upgrading biogas flows up to 40 Nm3/h. It is called EPUROGAS. Two main research axes were obtained with a preliminary study on a prototype: biogas leaks were detected at the water outlet and stripping water with air allowed both CH4 and CO2 production. Works have led through innovation with two patents: an enlarged column bottom and a static mixer to enhance CO2 desorption from water. During this work, experimental results were collected during operation and statistically studied. Thanks to theoretical studies, two predictive models were built to predict CO2 absorption efficiency and CH4 rate recover. Moreover, two complementary processes were studied. SATUROMETRIX is a laboratory apparatus that aims to characterize gas/liquid equilibrium under pressure for mixed gases and a complex liquid phase. PSA system is an adsorption process for biogas upgrading operating with biogas or half upgraded biogas. It leads to Compressed Natural Gas at 200 bars. Finally, EPUROGAS and PSA were coupled in order to conduct their energetic study and their Life Cycle Analysis
APA, Harvard, Vancouver, ISO, and other styles
20

Foster, Paul J. "Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1789.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
21

Charlton, Christy. "Quantum Cascade Lasers for Mid-Infrared Chemical Sensing." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/13953.

Full text
Abstract:
The mid-infrared (MIR) spectral range (2-20 m) is particularly useful for chemical sensing due to the excitation of fundamental rotational and vibrational modes. In the fingerprint region (10-20 m), most organic analytes have unique absorption patterns; absorption measurements in this region provide molecule-specific information with high sensitivity. Quantum cascade lasers (QCLs) present an ideal light source for (MIR) chemical sensing due to their narrow linewidth, high spectral density, compact size, and ease of fabrication of nearly any MIR wavelength. As the emission wavelength is dependent on layer size within the heterostructure rather than material composition, various wavelengths in the MIR can be achieved through bandstructure engineering. High sensitivity measurements have been achieved in both gas and liquid phase by developing integrated sensing systems. The laser emission frequency is selected to match a strong absorption feature for the analyte of interest where no other interfering bands are located. A waveguide is then developed to fit the application and wavelength used. Gas sensing applications incorporate silica hollow waveguides (HWG) and an OmniGuide fiber (or photonic bandgap HWG). Analyte gas is injected into the hollow core allowing the HWG or OmniGuide to serve simultaneously as a waveguide and miniaturized gas cell. Sensitivities of parts per billion are achieved with a response time of 8 s and a sample volume of approximately 1 mL. Liquid sensing is achieved via evanescent wave measurements with planar waveguides of silver halide (AgX) and gallium arsenide (GaAs). GaAs waveguides developed in this work have a thickness on the order of the wavelength of light achieving single-mode waveguides, providing a significant improvement in evanescent field strength over conventional multimode fibers. Liquid samples of L volume at the waveguide surfaces are detected. QCLs have begun to be utilized as a light source in the MIR regime over the last decade. The next step in this field is the development of compact and highly integrated device platforms which take full advantage of this technology. The sensing demonstrations in this work advance the field towards finding key applications in medical, biological, environmental, and atmospheric measurements.
APA, Harvard, Vancouver, ISO, and other styles
22

Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase. Experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitatated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.

Full text
Abstract:
Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17¿-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17¿-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.
Ministry of Higher Education in Libya and the Libyan Cultural Centre and Educational Bureau in London.
APA, Harvard, Vancouver, ISO, and other styles
23

Dixit, Onkar. "Upgrading Biogas to Biomethane Using Absorption." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-189059.

Full text
Abstract:
Questions that were answered in the dissertation: Which process is suitable to desulphurize biogas knowing that chemical absorption will be used to separate CO2? Which absorption solvent is suitable to separate CO2 from concentrated gases such as biogas at atmospheric pressure? What properties of the selected solvent, namely aqueous diglycolamine (DGA), are already known? How to determine solvent properties such as equilibrium CO2 solubility under absorption and desorption conditions using simple, but robust apparatuses? What values do solvent properties such as density, viscosity and surface tension take at various DGA contents and CO2 loadings? How do primary alkanolamine content and CO2 loading influence solvent properties? What is the optimal DGA content in the solvent? What is the optimal desorption temperature at atmospheric pressure? How can equilibrium CO2 solubility in aqueous DGA solvents be simulated? What is the uncertainty in the results? How to debottleneck an absorber and increase its gas-treating capacity? How to determine the optimal lean loading of the absorption solvent? What are the characteristics of the absorption process that uses aqueous DGA as the solvent to separate CO2 from biogas and is more energy efficient and safer than the state-of-the-art processes? How to quantitatively compare the hazards of absorption solvents? What is the disposition of the German population towards hazards from biogas plants? What are the favourable and adverse environmental impacts of biomethane?
Fragen, die in der Dissertation beantwortet wurden: Welches Verfahren ist zur Entschwefelung von Biogas geeignet, wenn die chemische Absorption zur CO2-Abtrennung genutzt wird? Welches Absorptionsmittel ist geeignet, um CO2 aus konzentrierten Gasen, wie Biogas, bei atmosphärischem Druck abzutrennen? Welche Eigenschaften des ausgewählten Absorptionsmittels, wässriges Diglykolamin (DGA), sind bereits bekannt? Wie wird die CO2-Gleichgewichtsbeladung unter Absorptions- und Desorptionsbedingungen mit einfachen und robusten Laborapparaten bestimmt? Welche Werte nehmen die Absorptionsmitteleigenschaften wie Dichte, Viskosität und Oberflächenspannung bei verschiedenen DGA-Gehalten und CO2-Beladungen? Wie werden die Absorptionsmitteleigenschaften durch den Primäramin-Gehalt und die CO2-Beladung beeinflusst? Was ist der optimale DGA-Gehalt im Absorptionsmittel? Was ist die optimale Desorptionstemperatur bei atmosphärischem Druck? Wie wird die CO2-Gleichgewichtsbeladung im wässrigen DGA simuliert? Welche Ungenauigkeit ist zu erwarten? Wie wird eine Absorptionskolonne umgerüstet, um die Kapazität zu erweitern? Wie wird die optimale CO2-Beladung des Absorptionsmittels am Absorbereintritt (im unbeladenen Absorptionsmittel) bestimmt? Was sind die Prozesseigenschaften eines Absorptionsverfahrens, das wässriges DGA als Absorptionsmittel nutzt sowie energieeffizienter und sicherer als Verfahren auf dem Stand der Technik ist? Wie kann das Gefahrenpotenzial von Absorptionsmittel quantitativ verglichen werden? Wie werden Gefahren aus einer Biogasanlage durch die deutsche Bevölkerung wahrgenommen? Welche positive und negative Umweltauswirkung hat Biomethan?
APA, Harvard, Vancouver, ISO, and other styles
24

Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase : experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.

Full text
Abstract:
Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas-liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17β-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17β-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.
APA, Harvard, Vancouver, ISO, and other styles
25

Stevanovic, Stéphane. "Absorption sélective de gaz par des liquides ioniques basés sur des anions carboxylates ou des anions tris (pentafluoroethyl) trifluorophosphates." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00822155.

Full text
Abstract:
Différentes familles de liquides ioniques ont été sélectionnées pour leur capacité d'absorption de gaz et plus particulièrement de dioxyde de carbone. L'objectif de ces travaux est de définir les liquides ioniques les plus à même d'être utilisés en tant qu'absorbants dits alternatifs dans les procédés de captage de gaz, l'enjeu principal étant à terme de diminuer les coûts de production des procédés industriels. Les systèmes retenus sont des liquides ioniques purs issus de la combinaison de cations imidazolium, pyrrolidinium et phosphonium avec des anions de type carboxylate ou tris (pentafluoroethyl) trifluorophosphate ainsi que des mélanges binaires de liquides ioniques avec anion carboxylate + eau. L'absorption de différents gaz - dioxyde de carbone, azote, protoxyde d'azote et éthane - dans les liquides ioniques purs ainsi que dans les mélanges liquide ionique +eau a été mesurée dans une gamme de températures comprises entre 303.15 et 353.15 K et pour des pressions proches de l'atmosphérique. La sélectivité des liquides ioniques pour l'absorption de dioxyde de carbone par rapport aux autres gaz a pu être déterminée. La caractérisation de l'absorption de gaz est fonction des systèmes étudiés, les interactions entre les gaz et certains liquides ioniques (ou certains mélanges liquide ionique + eau) étant uniquement de type physique alors que dans d'autres systèmes, l'absorption est le résultat à la fois d'interactions physiques mais également de la présence de réaction chimique.
APA, Harvard, Vancouver, ISO, and other styles
26

Makiyama, Patricia Akemi. "Aperfeiçoamento de um simulador de sistemas de refrigeração de absorção agua-amonia e sua aplicação para projeto de um sistema movido a gas de escape de motor diesel." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263229.

Full text
Abstract:
Orientador: Jose Ricardo Figueiredo
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-12T16:34:55Z (GMT). No. of bitstreams: 1 Makiyama_PatriciaAkemi_D.pdf: 909858 bytes, checksum: 44f3dcd6439a819df8a8d16fa7f5d458 (MD5) Previous issue date: 2008
Resumo: Este estudo apresenta o desenvolvimento de um programa pré-existente de simulação de um sistema de refrigeração por absorção água-amônia que utiliza como fonte de energia os gases de exaustão de um motor diesel de um grupo diesel-gerador. O projeto foi executado em quatro etapas. Um dimensionamento inicial dos diversos componentes envolveu relações puramente termodinâmicas, e baseou-se no arbítrio de diferenças de temperatura nos diversos trocadores de calor e algumas condições operacionais e ambientais, como capacidade de refrigeração e temperatura de entrada da água de resfriamento nos condensadores e absorvedor. Obteve-se, assim, o porte de cada equipamento do sistema de refrigeração em termos de parâmetros, tais como os coeficientes globais de transferência de calor multiplicado pelas áreas de cada componente ou a efetividade multiplicada pela mínima capacidade térmica horária. Na segunda etapa, foi feito o detalhamento construtivo de cada componente do sistema com o intuito de se chegar o mais próximo possível aos resultados do projeto inicial. Foram introduzidas as relações para o cálculo de transferência de calor de cada componente do sistema, o cálculo dos respectivos coeficientes de transferência de calor e as perdas de cargas relevantes ao cálculo da potência elétrica auxiliar demandada pelo sistema. Uma vez definida a configuração inicial de um sistema de refrigeração por absorção específico, buscou-se a maximização da potência térmica do evaporador e a minimização da potência elétrica auxiliar total requerida pelo sistema, variando-se parâmetros construtivos (comprimento, diâmetro e número de tubos) de cada trocador de calor. Os comprimentos, número e diâmetro dos tubos foram, então, fixados em função dos resultados obtidos nesta etapa do projeto. Definida a configuração final do sistema, calculou-se a capacidade de produção de gelo em barras pelo sistema de refrigeração por absorção proposto em função da demanda de energia elétrica ao longo do dia para a Região Norte Amazônica. Na quarta etapa do projeto, o absorvedor foi estudado isoladamente. O sistema de refrigeração por absorção proposto, que utiliza os gases de escape de um motor diesel de 123 kW de potência máxima de um grupo diesel-gerador de pequeno porte, possui uma capacidade de produção de 372 barras de gelo de 10 kg por dia, operando o dia inteiro, ou de 150 barras, considerando-se horário comercial (8h às 18h horas).
Abstract: This work shows the development of an ammonia-water absorption refrigeration system pre-existing simulation program, which uses diesel engine exhaust gases from a diesel-generator group as energy source. The project was implemented in four stages. An initial design of its components involved solely thermodynamic relations, and was based on the arbitration of temperature differences in the different heat exchangers and some environmental and operational conditions, such as cooling water inlet temperature in condensers and absorber and refrigeration capacity. The size of each refrigeration system equipment was obtained in terms of parameters such as overall heat transfer coefficients multiplied by the areas of each component or the effectiveness multiplied by the hourly minimum thermal capacity. In the second stage, the detailed construction of each component of the system was made with the aim of reaching as close to the original design parameters. The heat transfer equations for each system component, the heat transfer coefficient calculation, and the relevant pressure drops related to the calculation of required electric power were introduced. After the initial configuration had been defined of a specific absorption refrigeration system, an additional adjustment took place, aiming at the maximization of the thermal power of the evaporator and the minimization of the total electric power required by the system. This fine tunning was carried out by varying the construction parameters (length, diameter and number of tubes) of each heat exchanger. The length, number and diameter of the tubes were then set according to the results obtained in this part of the project. After settling the system configuration, the production capacity of ice bars of the proposed absorption refrigeration system was estimated according to the demand for electricity along the day for the northern Amazon region. In the fourth stage of the project, the absorber has been studied in separate, as a standalone module. The proposed absorption refrigeration system in this work, which uses the exhaust gases from a diesel engine of a small diesel-generator group, showed to have a production capacity of ice, measured in bars of 10 kg, equals to 372 bars a day (3720 kg), working all day, or 150 bars a day (1500 kg), if considering only the period of 8 working hours (business hours, from 8 am to 6 pm).
Doutorado
Termica e Fluidos
Doutor em Engenharia Mecânica
APA, Harvard, Vancouver, ISO, and other styles
27

Aurousseau, Marc. "Étude d'un procédé électrochimique de dépollution d'effluents gazeux contenant du dioxyde de soufre et des oxydes d'azote, par voie directe ou indirecte à l'aide du couple Redox Ce(III)/Ce(IV)." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL138N.

Full text
Abstract:
Dans le cadre de la lutte contre la pollution atmosphérique, la réduction des émissions de dioxyde de soufre (SO2) et d'oxydes d'azote (NOx) est une des préoccupations majeures des pays industrialisés. L’objectif de ce travail est de proposer et d'étudier un procédé de dépollution, d'effluents gazeux contenant ces espèces polluantes, par voie humide conduisant à la production de produits valorisables, des solutions concentrées et séparées des acides correspondants dans le cas présent. Deux voies électrochimiques ont été prospectées et développées. La première repose sur la mise en œuvre du couplage entre l'absorption de l'espèce polluante et son électro-oxydation à la surface d'une électrode de graphite. Cette étude ne concerne que le dioxyde de soufre et comprend une modélisation simplifiée du phénomène de couplage ainsi qu'une validation expérimentale de ce modèle. Son objectif principal était de démontrer le bien-fondé du couplage absorption/électro-oxydation, mais la faible solubilité du monoxyde d'azote nous a conduit à abandonner cette voie. Par la seconde, SO2 et NOx sont oxydés par le cérium tétravalent en milieu acide. Nous nous sommes particulièrement attachés à étudier les réactions mises en jeu et leur cinétique ainsi que la régénération dans une cellule électrochimique de l'espèce oxydante. Les résultats obtenus ont conduit à la mise en œuvre d'un pilote actuellement en cours de fonctionnement auprès de notre partenaire industriel
APA, Harvard, Vancouver, ISO, and other styles
28

Blanchon, Le Bouhelec-Tribouillois Émilie. "Contribution à la thermodynamique de l'absorption des gaz acides H2S et CO2 dans les solvants eau-alcanolamine-méthanol : mesures expérimentales et modélisation." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL046N/document.

Full text
Abstract:
Ce travail s'inscrit dans le cadre du développement de nouveaux procédés de désacidification de gaz naturel à travers l'étude thermodynamique des équilibres entre les gaz acides (CO2 et H2S) et un solvant mixte. Ce solvant résulte de la combinaison d'un solvant chimique (solution aqueuse de diéthanolamine) et d'un solvant physique (méthanol). Couplant équilibres chimique et physique, la modélisation de ces systèmes nécessite l'élaboration de modèles complexes et une large gamme de données d'équilibre liquide-vapeur. La première partie de ce travail est consacrée à l'acquisition de données expérimentales de solubilité des gaz acides dans le solvant mixte. En étendant le champ d'application d'un appareillage fonctionnant en méthode synthétique, nous avons acquis des données originales de solubilité des mélanges CO2 + H2S dans des solvants eau-diéthanolamine-méthanol. Dans la seconde partie, la modélisation simultanée des équilibres chimiques et physiques est réalisée. L'approche hétérogène développée combine le modèle NRTL-Electrolyte pour représenter la phase liquide avec l'équation d'état de Peng-Robinson pour décrire le comportement de la phase vapeur. La procédure d'ajustement des paramètres est graduelle si bien que le système complet eau-diéthanolamine-méthanol-CO2-H2S est décrit de manière prédictive, les paramètres du modèle NRTL-Electrolyte ayant été déterminés sur des systèmes inférieurs. L'effet de solvatation du méthanol est aussi mis en valeur. Nous nous sommes également intéressés au calcul des chaleurs d'absorption et à l'extension de notre modèle à d'autres alcanolamines
This work is related to the development of new processes about gas sweetening with hybrid solvents coupling a chemical one (aqueous solution of diethanolamine) with a physical one (methanol). In the liquid phase, CO2 and H2S react with diethanolamine so that the VLE description of these systems is quite complex and requires experimental data. The first part of this work is dedicated to the experimental determination of acid gases + hybrid solvent solubility data. The experimental apparatus was improved to study H2S solubility and CO2 + H2S mixtures solubility in water-diethanolamine-methanol solvents. In the second part, the simultaneous representation of chemical and phase equilibria was realised. The heterogeneous approach developed here combines the Peng-Robinson equation of state for the vapour phase with the Electrolyte-NRTL model for the liquid phase. Parameters are fitted gradually so that the entire system water-diethanolamine-methanol-CO2-H2S system is extrapolated using Electrolyte-NRTL parameters determined by fitting experimental acid gas partial pressures of lower systems. Methanol effect is also described. An original calculation of heat of absorption was also developed. We extended the use of our approach to study others alkanolamines
APA, Harvard, Vancouver, ISO, and other styles
29

Lema, Rodríguez Marcos. "Multiphase fluid hammer: modeling, experiments and simulations." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209540.

Full text
Abstract:
This thesis deals with the experimental and numerical analysis of the water hammer phenomenon generated by the discharge of a pressurized liquid into a pipeline kept under vacuum conditions. This flow configuration induces several multiphase phenomena such as cavitation and gas desorption that cannot be ignored in the water hammer behavior.

The motivation of this research work comes from the liquid propulsion systems used in spacecrafts, which can undergo fluid hammer effects threatening the system integrity. Fluid hammer can be particularly adverse during the priming phase, which involves the fast opening of an isolation valve to fill the system with liquid propellant. Due to the initial vacuum conditions in the pipeline system, the water hammer taking place during priming may involve multiphase phenomena, such as cavitation and desorption of a non-

condensable gas, which may affect the pressure surges produced in the lines. Even though this flow behavior is known, only few studies model the spacecraft hardware configuration, and a proper characterization of the two-phase flow is still missing. The creation of a reliable database and the physical understanding of the water hammer behavior in propulsion systems are mandatory to improve the physical models implemented in the numerical codes used to simulate this flow configuration.

For that purpose, an experimental facility modeling a spacecraft propulsion system has been designed, in which the physical phenomena taking place during priming are generated under controlled conditions in the laboratory using inert fluids. An extended experimental campaign was performed on the installation, aiming at analyzing the effect of various working parameters on the fluid hammer behavior, such as the initial pressure in the line, liquid saturation with the pressurant gas, liquid properties and pipe configuration. The influence of the desorbed gas during water hammer occurrence is found to have a great importance on the whole process, due to the added compressibility and lower speed of sound by an increasing amount of non-condensable gas in the liquid + gas mixture. This results in lower pressure levels and faster pressure peaks attenuation, compared to fluids without desorption. The two-phase flow was characterized by means of flow visualization of the liquid front at the location where the fluid hammer is generated. The front arrival was found to be preceded by a foamy mixture of liquid, vapor and non-condensable gas, and the pressure wave reflected at the tank may induce the liquid column separation at the bottom end. While column separation takes place, the successive pressure peaks are generated by the impact of the column back against the bottom end.

The resulting experimental database is then confronted to the predictions of the 1D numerical code EcosimPro/ESPSS used to assess the propulsion system designs. Simulations are performed with the flow configuration described before, modeling the experimental facility. The comparison of the numerical results against the experimental data shows that aspects such as speed of sound computation with a dissolved gas and friction modeling need to be improved.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles
30

Makhloufi, Camel. "Étude expérimentale et modélisation d'un procédé de captage en CO2 en postcombustion par l'ammoniaque à l'aide de contacteurs membranaires : du matériau à l'évaluation de l'intensification de l'absorption." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0318/document.

Full text
Abstract:
L'absorption du CO2 à l'ammoniaque au sein d'une colonne garnie est une technologie prometteuse pour capter le CO2 en postcombustion. La fuite d'NH3 engendrée par la volatilité de ce solvant gêne néanmoins le déploiement de ce procédé. Dans cette étude, la faculté des contacteurs membranaires à permettre des performances d'absorption du CO2 intensifiées et des pertes en NH3 réduites par rapport au procédé conventionnel est évaluée. Pour cela, l'emploi de fibres composites innovantes constituées d'une peau dense assurant un transport sélectif du CO2 vis-à-vis de NH3 a été proposé. Compte tenu des propriétés de ces molécules, aucun matériau ne présentait jusqu'alors de sélectivité de séparation favorable au CO2. Des essais de temps-retards ont permis de révéler 6 matériaux fluorés présentant les propriétés de sélectivités inverses recherchées. Le Teflon AF2400, polymère hautement perméable au CO2, a été choisi pour constituer les fibres creuses composites employées lors d'expériences d'absorption. Leurs performances ont été comparées à celles de contacteurs commerciaux microporeux (Oxyphan) et composites (Oxyplus) pour différentes conditions opératoires. Alors qu'aucune expérience stable n'a pu être achevée avec les contacteurs microporeux du fait de la précipitation de sels d'ammonium, les contacteurs composites ont permis des performances de capture supérieures aux objectifs fixés. La modélisation 2D du transfert de matière a permis de révéler le rôle prépondérant du support microporeux dans les performances d'absorption observées. Enfin, une intensification élevée des performances d'absorption du CO2 et des pertes en NH3 fortement réduites par rapport au procédé conventionnel ont pu être démontrées
Aqueous ammonia as a solvent for post-combustion CO2 capture in a packed column is seen as a promising technology. Nevertheless, ammonia volatility is a considerable drawback for its large scale deployment. In this study, the ability of hollow fiber membrane contactors to significantly improve CO2 mass transfer performances while mitigating ammonia losses when compared to packed column is evaluated. In that purpose, the use of innovating composite fibers made of a thin dense layer selective for CO2 over NH3 is proposed. Up to now, a faster permeation of CO2 compared to NH3 in dense polymers was totally unexpected and to our knowledge unexplored. Time-lag experiments have revealed a series of 6 fluorinated structures showing the desired reverse selectivity properties. Teflon AF2400 has been selected as the dense skin of composite fibers used during absorption experiments. Their performances have been compared, for different operating conditions, to those given by commercial microporous (Oxyphan) and composite (Oxyplus) membrane contactors. Due to ammonium salt precipitation issues, no stable experiment has been achieved using microporous membrane contactors. At the opposite, absorption efficiencies higher than post-combustion capture standards have been reached using composite membrane contactors. 2D mass transfer modeling has revealed the controlling role of the microporous support in the observed absorption performances. Finally, high CO2 mass transfer intensification factor and drastically reduced ammonia losses have been shown
APA, Harvard, Vancouver, ISO, and other styles
31

Wyatt, Victor T. "Characterization of gas-expanded liquids." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/26006.

Full text
APA, Harvard, Vancouver, ISO, and other styles
32

Toro, Molina Carol. "Comparaison du captage du CO2 en postcombustion par des solutions d'ammoniaque et d'amines organiques : Évaluation en contacteurs direct et indirect, par des approches cinétiques, thermodynamiques et par modélisation." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2013. http://pastel.archives-ouvertes.fr/pastel-00935386.

Full text
Abstract:
Actuellement, la production d'énergie est de plus en plus associée à une hausse simultanée d'émissions de Gaz à Effet de Serre (GES). Malgré les inquiétudes concernant les GES dans l'atmosphère, les énergies fossiles resteront probablement longtemps la principale source d'énergie primaire à l'échelle mondiale. Le procédé de captage de CO2, principal gaz à effet de serre, généralement préconisé est un procédé d'absorption chimique avec de la monoéthanolamine (MEA). Ce procédé pose de nombreux problèmes comme le coût de la régénération de l'amine. Cette étude s'intéresse à une alternative consistant à absorber chimiquement le dioxyde de carbone dans une solution aqueuse d'ammoniac. Par ailleurs, dans le but d'améliorer les procédés de captage et d'intensifier le transfert gaz-liquide, des techniques de captage à base de membranes (contacteurs membranaires) ont été développées et couplées à l'absorption chimique. Dans un premier temps des mesures d'absorption du CO2 à partir d'une solution aqueuse d'ammoniac ont été réalisées. Ces mesures ont été effectuées entre 278 et 303 K dans un réacteur fermé de type cellule de Lewis. Le taux de charge maximum, la pression partielle du CO2 à l'équilibre ont été déterminés. Les performances ont été comparées à celles de solvants conventionnels tels que la MEA et la N-méthyldiéthanolamine (MDEA). Dans un second temps, des mesures d'absorption à travers un contacteur membranaire ont été réalisées. L'efficacité de captage est étudiée en fonction de la nature des matériaux constituants la membrane et des paramètres opératoires. Les résultats obtenus montrent qu'il est possible de capter le CO2 par l'ammoniaque à travers une membrane avec une efficacité de captage supérieure à 90 %. La membrane limite les pertes d'ammoniaque mais ne les élimine pas. La simulation du fonctionnement de la centrale thermique alimentée au charbon pulvérisé (CP) intégrant le captage de CO2 a été réalisée à l'aide du logiciel Aspen Plus. Les fumées issues de la post-combustion sont captées par différents solvants. Une étude paramétrique a été conduite afin de préciser les conditions optimales pour capter le CO2 par l'ammoniaque. Des comparaisons de dépense énergétique dans le cas de la régénération pour les solvants NH3, MEA et MDEA ont été réalisées. L'étude comparative suggère que l'absorption chimique utilisant l'ammoniaque comme solvant est un des procédés les plus intéressants pour la centrale CP.
APA, Harvard, Vancouver, ISO, and other styles
33

Xia, Qi 1962. "Gas absorption kinetics in STR's." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36732.

Full text
Abstract:
Experiments were carved out in a stirred tank reactor with both two phase and three phase systems. A systematic examination of the effect of solid particles on parameters such as volumetric liquid-side mass transfer coefficient kLa, specific interfacial area a, gas holdup epsilong, bubble size dB, and average bubble residence time tau, was conducted. Both dimensional and dimensionless correlations were generated and conclusions were drawn.
The work was carried out in the context of the industrial experience that stirred tank reactors are widely used in both metallurgical and chemical engineering processes that often involve gas absorption in two and three phase systems. The effect of solids loading on the oxygen absorption rate in stirred tank reactors is complex due to the interactions between bubbles and solid particles, and also between other parameters. The measurement of some parameters, such as bubble size, specific interfacial area, volumetric mass transfer coefficient, is difficult, and there are many discrepancies in the literature with respect to the form of the correlation for oxygen absorption rate and bubble size and also the explanation of the internal mechanisms.
The present work found that kLa decreased with increasing solids volume fraction. This decrease was as much as 50% when solids loading was increased from 0 (water) to 14 vol% at a superficial gas velocity of 0.64 cm/s and a impeller speed of 400 rpm. The primary reason for this was due to the enhancing effect of solids on bubble coalescence and the increase of slurry density. Kolmogroff's turbulence theory was proved not applicable to the present STR and conditions. The cause for this was believed to be due to the fact that the power density in the STR was far from homogeneous, and the dynamic equilibrium between bubble breakup and the bubble coalescence was not established.
Bubble size, dB, was found to be increased by increasing solids volume fraction. The increase was due to the direct enhancing effect of solids on bubble coalescence and due to less bubble recirculation, i.e., change of the bulk flow pattern, with increased solids loading. There was no direct relationship found between a change of the apparent viscosity of slurry and a change of bubble size. Therefore, the manner by which many people incorporated apparent viscosity into the correlation of dB is inappropriate.
To properly describe the extent of bubble coalescence in three phase systems, a new parameter, the coalescence factor, fc, was defined in the present work. It was found that the coalescence factor decreased with increasing solids volume fraction and power input, but decreased with increasing superficial gas velocity.
APA, Harvard, Vancouver, ISO, and other styles
34

Kren, Christoph. "Flue gas fired absorption chillers." kostenfrei, 2008. https://mediatum2.ub.tum.de/node?id=965968.

Full text
APA, Harvard, Vancouver, ISO, and other styles
35

Xia, Qi. "Gas absorption kinetics in STR's." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0032/NQ64694.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

Repper, Stephen. "Carbon monoxide absorption by copper(I) containing ionic liquids." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/7674/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Zora, Jandrić. "Razvoj hromatografskih metoda za simultano određivanje tropanskih alkaloida i glikoalkaloida i praćenje apsorpcije i translokacije atropina 14C u pšenici." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2011. https://www.cris.uns.ac.rs/record.jsf?recordId=76985&source=NDLTD&language=en.

Full text
Abstract:
U okviru doktorske disertacije su razvijeni i optimizovani postupci pripreme uzoraka hrane (žitarica, sirovina, poluproizvoda i prehrambenih proizvoda na bazi žitarica, voća i povrća) i stočne hrane, kao i simultano određivanje tropanskih i glikoalkaloida primenom gasne i tečne hromatografije uz maseno-spektrometrijsku detekciju. Razdvajanje alkaloida primenom gasne hromatografije je izvedeno na kapilarnoj koloni (HP-5MS UI), uz detekciju sa kvadrupolnom masenom spektrometrijom SIM tehnikom, u intervalu m/z 50–550 a.m.u. Pri optimizovanim uslovima postignuto je razdvajanje homatropina, atropina i skopolamina u vremenu od 12.75 min, pri čemutropin i anisodamin nisu mogli biti detektovani. Glikoalkaloidi nisu direktno mogli biti određivani gasnom hromatografijom usled njihove visoke molekulske mase i male isparljivosti. Za simultano određivanje tropanskih alkaloida (tropin, l-hiosciamin, atropin, skopolamin, homatropin i anisodamin) i glikoalkaloida (α-solanin i α-kakonin) validirana je brza i osetljiva multirezidualna LC–MS/MS metoda. Korišćena je disperzivna čvrsto-fazna ekstrakcija sa 0.5% mravlje kiseline u acotonitrilu/vodi (75:25, v/v), solima magnezijum sulfat, natrijum hlorid i natrijum citrat kao i C18 sorbent. Analiti su razdvojeni na Chirobiotic V koloni, sa mobilnom fazom sastavljenom od 10 mM amonijum formata u voda/acetonitril (90:10, v/v) i metanol/acetonitril (50:50, v/v), mešanim u odnosu 20:80 (v/v). Detekcija komponenti je izvedena u pozitivnom elektrosprej modu (ESI+), korišćenjem reakcionog višestrukog monitoring akvizacionog moda (MRM). Optimizovana tečno hromatografska metoda je podrazumevala brz i jednostavan proces ekstrakcije, sa prinosom od 61-111% za pojedine alkaloide, dobru linearnost u širokom opsegu (5-80 μg/kg, r2=0.998), dobru selektivnost, robusnost i preciznost (CV < 5%). Granica detekcije (LOD) za sve alkaloide je bila u opsegu od 0.74 do 0.79 ng/g dok se granica kvantifikacije (LOQ) kretala od 2.17 do 2.46 ng/g u svim žitaricama, izuzev za tropin u soji i lanenom semenu (LOD = 1.55 i LOQ = 4.91 ng/g). Pri analizi uzoraka sa tržišta alkaloidi nisu detektovani u analiziranim uzorcima hrane, kao što su: pšenica, raž, kukuruz, brašno od mešanih žitarica, kukuruzno brašno, biskvit i krekeri. Stočna hrana namenjena ishrani svinja i peradi je sadržala atropin, skopolamin, α-solanin i α-kakonin u koncentracionom opsegu od 3.6 do 21.7 ng/g. Atropin i skopolamin su detektovani u koncentracionom opsegu od 2.8 do 9.8 ng/g u hrani namenjenoj ishrani krava i zečeva, dok u hrani nemenjenoj ishrani konja i divljih životinja alkaloidi nisu detektovani. U analiziranim uzorcima voća i povrća (jabuka, kruška, avokado, mrkva, krastvac i paprika) po prvi put u ovom radu su detektovani glikoalkaloidi, α-solanin i α-kakonin. Koncentracija oba glikoalkaloida se kretala u opsegu od 0.3 do 15 ng/g. Sadržaj glikoalkaloida u krompiru i čipsu (8708.9-18794.7 ng/g) se nalazio u okviru preporučenog ukupnog sadržaja glikoalkaloida od 200 mg/kg (sirova odvaga) (FAO/WHO, 1999). Apsorpcija i translokacija alkaloida od strane pšenice u koren, listove i stabljiku je ustanovljena upotrebom atropina 14C. Utvrđeno je da biljka nakon 15 dana apsorbuje 4.30% i 2.28% atropina 14C za niži (13676 dpm/g soil) i viši (37203 dpm/g soil) sadržaj standarda sa kojim je zemljište spajkovano, redom. Količina apsorbovanog atropina se smanjivala tokom rasta biljke. Biljka starosti 90 dana je apsorbovala 0.38% i 0.21% atropina 14C za niži i viši sadržaj standarda, redom. Povećanje koncentracije supstance u zemljištu nije uticalo na dalje povećanje apsorpcije. Do nagomilavanja supstance je došlo u listovima (83%) dok su niže koncentracije zabilježene u korenu (8.6%), stabljici (4.2%) i semenu (4.1%). U analiziranim uzorcima vode, koja je poticala od ispiranja zemljišta obogaćenog atropinom 14C, nakon 30 dana supstanca je detektovana u koncentraciji od 0.5%. Tokom vremena je ustanovljeno smanjenje ispiranja ove supstance (0.01% nakon 90 dana). Analiza uzoraka zemljišta nakon 30 i 60 dana je pokazala značajne adsorpcione osobine atropina, tako da je količina čvrsto adsorbovanog (neekstrahovanog) atropina iznosila 60% i 70%, redom. Zaostali atropin je bio stabilan i nakon 90 dana.
The methods of sample preparation have been developed and optimized for food (grains, raw materials, food products based on grains and fruits and vegetables) and feed analyses for the purpose of simultaneous determination of tropane and glycoalkaloids by gas and liquid chromatography hyphenated to mass spectrometry. Separation of alkaloids by gas chromatography was achieved by using capillary column HP-5MS UI. The alkaloids have been detected by using a quadrupole mass spectrometer inSIM mode for the range of m/z 50–550 a.m.u. Under optimised conditions, good separation of homatropine, atropine and scopolamine was achieved after 12.75 min, while tropine and anisodamine couldn`t be detected. Glycoalkaloids could not be analysed directly by gas chromatography due to their high molecular weight and low volatility. For simultaneous determination of tropane alkaloids (tropine, atropine, scopolamine, homatropine, anisodamine) and glycoalkaloids (α-solanine, α-chaconine) fast and sensitive multiresidue LC–MS/MS method was validated. In sample preparation dispersive solid phase extraction (DSPE) was performed with 0.5% formic acid in acetonitrile/water (75:25, v/v) and a mixture of magnesium sulphate, sodium chloride, sodium citrate and C18 sorbent. The analytes were separated by isocratic HPLC on a Chirobiotic V column with the mobile phase that consisted of 10 mM ammonium formate in water/acetonitrile (90:10, v/v) and methanol/acetonitrile (50:50, v/v), mixed in the ratio of 20:80 (v/v).Compounds were detected in positive electrospray ionization mode (ESI+), using multi reaction monitoring (MRM). Optimised liquid-chromatographic method exhibited good linearity in the range 5-80 ng/g (r2=0.998). The method has shown to be specific, selective, accurate (recoveries from 61- 111%), precise (CV < 5%) and rugged. Calculated limits of detection (LOD) for all alkaloids were in the range 0.74-0.79 ng/g, while the limits of quantitation (LOQ) were in the range 2.2-4.9 ng/g in all grains, except for tropine in soybean and linseed (LOD = 1.55 and LOQ = 4.91 ng/g). The proposed method was applied in the analyses of samples obtained from local supermarkets. The alkaloids were not detected in following food samples:wheat, rye, maize, mixed grain flour, corn flour, biscuits and crackers. The feeds for pigs and chicken were the most contaminated with atropine, scopolamine, α-solanine and α-chaconine with the contents of alkaloids in the range of 3.6 to 21.7 ng/g. Atropine and scopolamine were detected in cattle and rabbit feed in concentrations ranging from 2.8 to 9.8 ng/g, while in feed for horses and wild animals none of the target alkaloids were detected. Conducted research reports for the first time the presence of glycoalkaloids, α-solanine and α-chaconine in fruit and vegetable samples (apple, pear, avocado, carrot, cucumber and paprika). The concentrations of these alkaloids were in the range of 0.3 to 15 ng/g. The content of glycoalkaloids in potato and chips complied with the recommended content of total glycoalkaloids concentration of 200 mg/kg (raw weight) (FAO/WHO, 1999). Absorption and translocation of alkaloids in wheat (roots, leaves, stem) was determined by using atropine 14C. It was found that young wheat after 15 days absorbed approximately 4.30% and 2.28% of atropine 14C for low (13676 dpm/g soil) and high (37203 dpm/g soil) spiked levels in soil, respectively. Increase in the spiked concentration in the soil did not affect higher absorption of atropine 14C in wheat. The highest accumulation of atropine 14C was observed in the leaves (83%) while lowerconcentrations were detected in the roots (8.6%), stems (4.2%) and seeds (4.1%). In collected water samples during the soil leaching, atropine 14C was detected in the concentration of 0.5%. Leaching decreased with the time (0.01% after 90 days). Analyses of soil samples after 30 and 60 days showed strong adsorption of atropine to the soil and quantity of adsorbed atropine was 60% and 70%, respectively. Adsorbed atropine in the soil was stable after 90 days.
APA, Harvard, Vancouver, ISO, and other styles
38

Southern, S. M. "Gas injection from diffuser sources into liquids." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315662.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

Philip, J. "Viscous liquids in bubble columns." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235274.

Full text
Abstract:
This dissertation is concerned with studies of highly viscous Newtonian and non-Newtonian liquids in bubble columns with, and without, draft tubes. The importance of the parameters influencing bubble column reactors is discussed with reference to previous work. The shapes and rise velocities of single bubbles in these liquids were studied in an 8.8cm diameter column, and the gas holdup, resulting from continuous bubbling of gas into this column, was also measured. Agreement between holdup predicted by the equation of Nicklin et al (1962), and experimental data in die present work and that of other workers is good. The limiting result of Dumitrescu (1943) was found to apply for fully developed slug flow in viscous non-Newtonian liquids in large columns. Gas holdup, in a 15cm diameter bubble column with a draft tube, consisted of large bubbles (slugs), which rapidly rose through the liquid, and very small bubbles, which accumulated in the liquid. These small bubbles were generated near the gas distributor and also at the liquid surface; less than 1% of the total gas flowrate into the system was converted into small bubbles for a highly viscous Newtonian liquid. The gas holdup due to small bubbles in non-Newtonian liquids was much less than that in Newtonian liquids. Large bubble velocities deduced from the bubble column measurements were consistent with the single bubble measurements. Liquid velocities in the 15cm column were measured by a neutrally buoyant flow follower; the liquid circulation rate was found to decrease with an increase in liquid viscosity. A model to predict the liquid circulation rate is outlined. The effect of scale-up on the gas holdup and liquid circulation rate was also studied experimentally in a 60cm square bubble column with a 30cm square draft tube. The bubble size distribution in this column was similar to the 15cm column but liquid velocities were higher, and gas holdup was smaller in the 60cm column.
APA, Harvard, Vancouver, ISO, and other styles
40

Firaha, Dzmitry [Verfasser]. "Molecular Approach toward Gases Absorption by Ionic Liquids / Dzmitry Firaha." Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1124540261/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Firaha, Dzmitry Sergeevich [Verfasser]. "Molecular Approach toward Gases Absorption by Ionic Liquids / Dzmitry Firaha." Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1124540261/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Slettebø, Eirik Slungaard. "Separation of Gas from Liquids in Viscous Systems." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8979.

Full text
Abstract:

Increased knowledge of the degassing process in separation of gas from oil is important in connection with development of subsea separation and boosting units for heavy oil fields. The focus in the thesis is on theory and equipment design for two-phase separation of oil and gas. A review of gravitational separators and compact separation technology with a focus on subsea installations is given first. An extensive literature review related to theory governing the degassing process is further presented. The effectiveness of the degassing process depends on the gas’ ability to migrate out of the oil. Bubble dynamics theory, especially correlations for calculation of a bubbles velocity in a liquid is therefore examined. Bubble size, fluid properties, especially liquid viscosity, and gas volume fraction in the liquid is decisive factors for the bubble velocity. A comparison of several correlations obtained in various literature is made to determine the best available for modeling degassing. Most of the correlations have a limited range of validity in terms of bubble size and Reynolds number. It is verified that they are highly inaccurate outside this range. A correlation developed to be valid for a large range of bubble sizes seems to predict bubble velocities reasonably well. Because of its large range of validity, this is chosen to be used in the development of a separator model. Some experimental work is performed on two liquids with different viscosity. It is verified that separation of gas in viscous liquids requires significantly more retention time for the smallest bubbles reach the liquid surface. Occasional deviations from the examined theory are observed, especially for the more viscous liquid. Based the chosen correlation for bubble velocity a simplified model for horizontal and vertical gravity separators is developed. Separator size, fluid properties, flow rate and distribution of bubbles are input parameters. The model calculates how much of the initial gas volume fraction that remains in the liquid after separation. Consequence of high liquid viscosity and distribution of bubble size and bubble distribution in the liquid are evaluated by use of the model. When the oil becomes very viscous is it important that separator and internals are designed to optimize the conditions for degassing. This implies among others an inlet device which provides an ability to control the bubble distribution and keep the size of bubbles as large as possible. Methods are suggested for increased effectiveness in degassing of heavy oils, by reducing viscosity, increase the coalescence rate and affecting the flow pattern. Separation of other phases and undesirable components is also important and may make it difficult to optimize the design for the degassing process. However, a separator should be efficient in all respects, making knowledge of the degassing process anyhow important. The thesis gives an overview of important parameters in the degassing process. Much work still remains to develop correlations and models which can give a more exact description of real systems. Continuous development in separator components and not at least compact separation technology is important to effectively be able to produce heavy oil, especially in terms of subsea installations.

APA, Harvard, Vancouver, ISO, and other styles
43

Spuller, Matthew Thomas. "Resist and Residue Removal Using Gas-Expanded Liquids." Diss., Available online, Georgia Institute of Technology, (2003), 2003. http://etd.gatech.edu/theses/available/etd-11072003-150305/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
44

Li, Peilin. "Amperometric gas sensing using room temperature ionic liquids." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:81f712fe-fa09-472e-b809-a7db4fc37ef6.

Full text
Abstract:
The work presented in this thesis aims at overcoming the limitations of current amperometric gas sensors. The applicability of room temperature ionic liquids to be employed as potential electrolyte in gas sensors has been examined. This thesis demonstrates that RTILs have great potential to replace conventional electrolytes due to their wide electrochemical windows, negligible vapour pressure, inherent conductivity and sensitivity. A model to simulate the current response at porous electrodes has also been proposed to provide a theoretical support for the future application of porous electrodes in gas sensors. The results of these researches are summarised as follows: Chapter 1 introduces the fundamentals of electrochemistry which are employed throughout this thesis. Chapter 2 presents a comprehensive review of the history and recent development of amperometric gas sensors with their specific applications and limitations presented. Room temperature ionic liquids, microelectrodes and porous electrodes are also introduced in this chapter to initially discuss their potential for gas sensors. Chapter 4 studies the interaction between carbon dioxide and an imidazolium cation based RTIL. The solubility and diffusion coefficient are determined by the analysis of chronoamperometry using the Shoup and Szabo equation. A mechanism of the interaction between CO2 and the RTIL is proposed and validated by theoretical modelling. Chapter 5 focuses on O2 uptake in a phosphonium cation based RTIL. A mechanism of O2 reduction in this RTIL is proposed, reflecting a two electron reduction pathway. Proof-of-concept for this RTIL to be developed into a CO2/O2 dual sensor is confirmed with by experiments with CO2/O2 gas mixtures. Oxygen uptake in a series of alkylammonium cation based RTILs has been carried out as described in Chapter 6. The diffusivity of O2 in RTILs does not follow the Stoke-Einstein equation but broadly decreases as the viscosity increases. Chapter 7 proposes a theoretical model for the electrochemical behaviour at porous electrodes. Studies with two types of porous electrodes are employed and validate the applicability for this model to simulate the current response at porous electrodes.
APA, Harvard, Vancouver, ISO, and other styles
45

Carvalho, Pedro Jorge Marques de. "Treatment of natural gas streams with ionic liquids." Doctoral thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7433.

Full text
Abstract:
Doutoramento em Engenharia Química
Being of high relevance for many technological applications, the solubility of sour gases in solvents of low volatility is still poorly described and understood. Aiming at purifying natural gas streams, the present work contributes for a more detailed knowledge and better understanding of the solubility of sour gases in these fluids, in particularly on ionic liquids. A new apparatus, developed and validated specially for phase equilibria studies of this type of systems, allowed the study of the solvent basicity, molecular weight and polarity influence on the absorption of carbon dioxide and methane. The non ideality of carbon dioxide solutions in ionic liquids and other low volatile solvents, with which carbon dioxide is known to form electron donor-acceptor complexes, is discussed, allowing the development of a correlation able to describe the carbon dioxide solubility in low volatile solvents. Furthermore, the non ideality of solutions of light compounds, such as SO2, NH3 and H2S, in ionic liquids is also investigated and shown to present negative deviations to the ideality in the liquid phase, that can be predicted by the Flory-Huggins model. For last, the effect of the ionic liquid polarity, described through the Kamlet-Taft parameters, on the CO2/CH4 and H2S/CH4 selectivities is also evaluated and shown to stand as a viable tool for the selection of ionic liquids with enhanced selectivities.
Apresentando uma elevada relevância em várias aplicações tecnológicas, a solubilidade de gases ácidos em solventes com baixa volatilidade é ainda mal descrita e compreendida. Este trabalho, visando a purificação de gás natural, contribui para uma melhor compreensão e para o desenvolvimento de uma descrição da solubilidade de gases ácidos neste tipo de compostos, em particular em líquidos iónicos. Um equipamento, desenvolvido e validado especialmente para estudar o equilíbrio de fases deste tipo de sistemas, permitiu o estudo detalhado da influência da basicidade, peso molecular e polaridade do líquido iónico na absorção de dióxido de carbono e metano. A não idealidade de soluções de dióxido de carbono tanto em líquidos iónicos como noutros solventes com baixa volatilidade, com os quais o dióxido de carbono forma complexos aceitadores-dadores de electrões, é investigado, permitindo o desenvolvimento de uma correlação capaz de descrever a solubilidade do dióxido de carbono em solventes com baixa volatilidade. Por sua vez, a não idealidade de soluções de compostos leves, como o SO2, NH3 e H2S em líquidos iónicos é também abordada, mostrando-se que os desvios negativos à idealidade na fase líquida observados podem ser descritos pelo modelo de Flory-Huggins. Por fim, o efeito da polaridade do líquido iónico, descrito através dos parâmetros Kamlet-Taft, nas selectividades de CO2/CH4 e H2S/CH4 é investigado, revelando-se uma ferramenta viável para a selecção de líquidos iónicos com elevada selectividade.
APA, Harvard, Vancouver, ISO, and other styles
46

Nguyen, Van Dong. "Speciation analysis of butyl- and phenyltin compounds in environmental samples by GC separation and atomic spectrometric detection." Doctoral thesis, Umeå : Department of Chemistry, Umeå University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-892.

Full text
APA, Harvard, Vancouver, ISO, and other styles
47

Rives, Sanz Ronny. "Theoretical and experimental study of the absorption process of ammonia in ionic liquids for absorption refrigeration systems." Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/670713.

Full text
Abstract:
Recentment, s'han proposat líquids iònics com a absorbents alternatius i ajustables per a refrigerants naturals en sistemes de refrigeració per absorció. Tanmateix, l’alta viscositat, la baixa difusivitat de la massa i la manca d’informació fiable sobre les propietats termofísiques de les seves mescles amb aquests refrigerants són limitacions importants per a la seva implementació efectiva. L'objectiu principal d'aquesta tesi és estudiar el procés d'absorció d'amoníac en líquids iònics per determinar l'evolució temporal de la taxa d'absorció i els perfils de concentració en el fluid absorbent. Aquest tipus de dades experimentals són útils per seleccionar líquids iònics adequats com a absorbents d'amoníac en sistemes de refrigeració i bombes de calor d'absorció nous. Els líquids iònics estudiats són: nitrat d’etilamoni (EAN); 1-etil-3-metilimidazoli-tetrafluoroborat ([emim] [BF4]); i 1- butil-3-metil-imidazoli-tetrafluoroborat ([bmim] [BF4]), amb diferents solubilitats i viscositats d'amoníac. El mètode de caiguda de pressió es va implementar per determinar l'evolució temporal de la taxa d'absorció de l'amoníac en les IL seleccionades, al llarg del procés d'absorció. Els experiments d’absorció es van realitzar a una dilució infinita d’amoníac, a la temperatura de 293,15 K i 303,15 K, durant més de 15 hores. La taxa d'absorció determinada d'amoníac a les IL va ser més de 20 vegades menor que a l'aigua.
Recientemente, se han propuesto líquidos iónicos como absorbentes ajustables alternativos para refrigerantes naturales en sistemas de refrigeración por absorción. Sin embargo, la alta viscosidad, la baja difusividad de masa y la falta de información confiable sobre las propiedades termofísicas de sus mezclas con estos refrigerantes son limitaciones importantes para su implementación efectiva. El objetivo principal de esta tesis es estudiar el proceso de absorción del amoniaco en líquidos iónicos para determinar la evolución temporal de la tasa de absorción y los perfiles de concentración en el fluido absorbente. Estos tipos de datos experimentales son útiles para seleccionar líquidos iónicos adecuados como absorbentes de amoníaco en nuevos sistemas de refrigeración por absorción y bombas de calor. Los líquidos iónicos estudiados son: nitrato de etilamonio (EAN); Tetrafluoroborato de 1-etil-3-metilimidazolio ([emim] [BF4]); y tetrafluoroborato de 1-butil-3-metil-imidazolio ([bmim] [BF4]), con diferentes solubilidades y viscosidades del amoniaco. Se implementó el Método de Caída de Presión para determinar el tiempo de evolución de la tasa de absorción de amoníaco en los IL seleccionados, a lo largo del proceso de absorción. Los experimentos de absorción se realizaron a dilución infinita de amoniaco, a las temperaturas de 293,15 K y 303,15 K, durante más de 15 horas.
Recently, ionic liquids have been proposed as alternative, adjustable absorbents for natural refrigerants in absorption refrigeration systems. However, the high viscosity, low mass diffusivity, and the lack of reliable information on the thermophysical properties of their mixtures with these refrigerants are important limitations for their effective implementation. The main objective of this thesis is to study the absorption process of ammonia in ionic liquids to determine the time evolution of the absorption rate and the concentration profiles in the absorbent fluid. These types of experimental data are useful for selecting ionic liquids suitable as absorbent of ammonia in new absorption refrigeration and heat pump systems. The ionic liquids studied are: ethylammonium nitrate (EAN); 1-ethyl-3-methylimidazolium-tetrafluoroborate ([emim] [BF4]); and 1-butyl-3-methyl-imidazolium-tetrafluoroborate ([bmim][BF4]), with different ammonia solubilities and viscosities. The Pressure Drop Method was implemented to determine the time evolution of the absorption rate of ammonia in the ILs selected, throughout the absorption process. Absorption experiments were performed at infinite dilution of ammonia, at the temperatures of 293.15 K and 303.15 K, during more 15 hours.
APA, Harvard, Vancouver, ISO, and other styles
48

Maxey, Natalie Brimer. "Transport and Phase-Transfer Catalysis in Gas-Expanded Liquids." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10411.

Full text
Abstract:
Gas-expanded liquids (GXL) are a new and benign class of liquid solvents that are intermediate in physical properties between normal liquids and supercritical fluids and therefore may offer advantages in separations, reactions, and advanced materials. Phase-transfer catalysis (PTC) is a powerful tool in chemistry that facilitates interaction and reaction between two or more species present in immiscible phases and offers the ability to eliminate the use of frequently expensive, environmentally undesirable, and difficult to remove polar, aprotic solvents. The work presented here seeks to further characterize the transport properties of GXLs and apply these new solvents to PTC systems, which could result in both greener chemistry and improved process economics. The transport properties of GXL are characterized by the measurement of diffusivities by the Taylor-Aris dispersion method and calculation of solvent viscosity based on those measurements. The measurement of these bulk properties is part of a larger effort to probe the effect of changes in the local structure surrounding a solute on the solution behavior. The two technologies of PTC and GXL are combined when the distribution of a phase-transfer catalyst between GXL and aqueous phases is measured and compared to changes in the kinetics of a reaction performed in the same system. The results show that increased reaction rates and more efficient catalyst recovery are possible with GXL solvents.
APA, Harvard, Vancouver, ISO, and other styles
49

Shukla, Charu L. "Computationally Probing the Cybotactic Region in Gas-Expanded Liquids." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14510.

Full text
Abstract:
Gas-expanded liquids (GXLs) are novel and environmentally benign solvent systems with applications in reactions, separations, nanotechnology, drug delivery, and microelectronics. GXLs are liquid mixtures consisting of an organic solvent combined with a benign gas, such as CO2, in the nearcritical regime. In this work, molecular dynamics simulations have been combined with experimental techniques to elucidate the cybotactic region or local environment in gas-expanded liquids. Molecular dynamics simulations show clustering of methanol molecules in carbon dioxide-methanol mixtures. This clustering was not observed in carbon dioxide-acetone mixtures. Furthermore, addition of carbon dioxide enhances diffusivity of solutes in gas-expanded media as shown by both simulations and Taylor-Aris dispersion experiments. Finally, local structure and local compositions around pyrene in carbon dioxide-methanol and carbon-dioxide acetone were investigated using simulations and UV-vis spectroscopy.
APA, Harvard, Vancouver, ISO, and other styles
50

Lakshmanan, Peter [Verfasser]. "Gas bubbles in pure and contaminated liquids / Peter Lakshmanan." München : Verlag Dr. Hut, 2010. http://d-nb.info/100997257X/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the bibliographies on the topic 'Gas Absorption in Liquids' for other source types:
Journal articles Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography