The diploma thesis is devoted to the separation of a gasseous pollutant (CO2) from a gas mixture using an experimental technology device - membrane contactor. The theoretical part is mostly focused on the recent progress in the field of membrane contactors. The theoretical part also contains theory of absorption, which is needed to understand the subject properly. The experimental part focuses on the construction of the experimental device. The efficiency of the device in absorption of carbon dioxide to an aqua solution of sodium hydroxide was tested. At the end, experimental data are discussed.

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.

Yes / The increasing concentration of carbon dioxide (CO2) in the atmosphere is a primary global environmental concern due to its detrimental impacts on climate change. A significant reduction in CO2 generation together with its capture and storage is an imperative need of the time. CO2 can be captured from power plants and other industries through various methods such as absorption, adsorption, membranes, physical and biological separation techniques. The most widely used systems are solvent based CO2 absorption method. The aim of this study was to analyze the effect of various random and structured packing materials in absorption column on CO2 removing efficiency. Aspen plus was used to develop the CO2 capture model for different packing materials with Monoethanolamine (MEA) solvent in order to optimize the system. It was found that the lowest re-boiler duty of 3,444 kJ/KgCO2 yield the highest rich CO2 loading of 0.475 (mole CO2/mole MEA) by using the BX type of structured packing having the highest surface area. The surface area of the different packing materials were inversely proportional to the temperature profiles along the column. Furthermore, the packing materials with higher surface areas yielded higher CO2 loading profiles and vice versa. The findings of this study and recommendation would help further research on optimization of solvent-based CO2 capturing technologies.

In recent years, membrane gas absorption technology has been considered as one of the promising alternatives to conventional techniques for CO2 capture due to its favorable mass transfer performance. As a hybrid approach of chemical absorption and membrane separation, it exhibits a number of advantages, such as operational flexibility, compact structure, high surface-area-to-volume ratio, linear scale up, modularity and predictable performance. One of the main challenges of membrane gas absorption technology is the membrane wetting by absorbent over prolonged operating time, which may significantly decrease the mass transfer coefficients of the membrane module. In this thesis, the experimental was set up to investigate the dependency of CO2 removal efficiency and mass transfer rate on various operating parameters, such as the gas and liquid flow rates, absorbent type and concentration and volume fraction CO2 at the feed gas inlet. In addition, the simultaneous removal of SO2 and CO2 was investigated to evaluate the feasibility of simultaneous desulphurization and decarbonization in the same membrane contactor. During 14 days of continuous operation, it was observed that the CO2 mass transfer rate decreased significantly following the operating time, which was attributed to partial membrane wetting. To better understand the wetting mechanism of membrane pores during their prolonged contact with absorbents, immersion experiments for up to 90 days were carried out. Various membrane characterization methods were used to illustrate the wetting process before and after the membrane fibers were exposed to the absorbents. The characterization results showed that the absorbent molecules diffused into the polypropylene polymer during the contact with the membrane, resulting in the swelling of the membrane. In addition, the effects of operating parameters such as immersion time and absorbent type on the membrane wetting were investigated in detail. Finally, based on the analysis results, methods to smooth the membrane wetting were discussed. It was suggested that improving the hydrophobicity of polypropylene membrane by surface modification may be an effective way to improve the long-term operating performance of membrane contactors. Therefore, the polypropylene hollow fibers were modified by depositing a thin superhydrophobic coating on the membrane surface to improve their hydrophobicity. The mixture of cyclohexanone and methylethyl ketone was considered as the best non-solvent to achieve the fiber surface with good homogeneity and acceptably high hydrophobicity. In the long-period operation, the modified membrane contactor exhibited more stable and efficient performance than the untreated one. Hence, surface treatment provides a feasibility of improving the system stability for CO2 capture from the view of long-term operation. / En av de tekniker som under senare framhållits som ett lovande alternativ till konventionell CO2-avskiljning är membran-gas-absorptionstekniken på grund av god prestanda vad gäller masstransport. Det blandade angreppssättet med både kemisk absorption och membranseparation har en rad fördelar, såsom driftflexibilitet, kompakt konstruktion, högt yt-volymsförhållande, linjär uppskalning, modularitet och förutsägbar prestanda. En av de viktigaste utmaningarna för membran-gas-absorptionstekniken är vätningen av membranet med absorbenten under långa drifttider, vilket väsentligt kan minska membranmodulens masstransportkoefficienter.  I avhandlingen har en rad olika driftparametrars påverkan på CO2-reningsgraden och massöverföringshastigheten undersökts. Driftparametrar inkluderar gas- och vätskeflöden, typ av absorbent och koncentration och volymfraktion av CO2 vid gasinloppet. Avskiljning av SO2 och CO2 har dessutom undersökts för att utvärdera möjligheten att samtidigt, i samma membranenhet, avlägsna svavel och kol. Under 14 dagars kontinuerlig drift konstaterades det att massöverföringshastigheten för CO2 minskade avsevärt med drifttiden, vilket hänfördes till partiell vätning av membranet.   För att bättre förstå mekanismerna för vätning av membranporer under långvarig kontakt med absorbenter genomfördes doppningsexperiment i upp till 90 dagar. Olika metoder för karakterisering av membran användes för att illustrera vätningsprocessen före och efter det att membranfibrerna exponerades för absorbenterna. Resultaten av karakteriseringen visade att absorbentmolekylerna spreds in i polypropenpolymeren under kontakten med membranet, vilket ledde till att membranet svällde. Dessutom undersöktes effekterna av driftsparametrar såsom nedsänkningstid och typ av absorbent i detalj. Slutligen, på grundval av analysresultaten, diskuterades metoder för att underlätta vätningen av membran. Att förbättra polypropylenmembranets hydrofobicitet genom modifiering av ytan föreslogs kunna vara ett effektivt sätt att förbättra den långsiktiga driftprestandan för membranenheter. Därför modifierades de ihåliga fibrerna av polyproylen med ett tunt lager av en superhydrofob beläggning på membranets yta för att förbättra hydrofobiciteten. En blandning av cyklohexanon och metyletylketon ansågs vara det bästa icke-lösningsmedlet för att få en fiber yta med god homogenitet och acceptabelt hög hydrofobicitet. Under lång driftperiod, uppvisade den modifierade membranenheten stabilare och effektivare prestanda än den obehandlade. Därför erbjuder ytbehandling en möjlighet till att förbättra systemets stabilitet för CO2-avskiljning när det gäller långsiktig drift. / VR-SIDA Swedish Research Links Programme

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.

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 / The goal of this research was to synthesize, characterize and study the potential of selected ionic liquids as solvents for the separation of ethane and ethene. The influence on ethene absorption of the presence of three different metallic cations, lithium (I), nickel (II) and copper (II) in an ionic liquid was also studied. The selected ionic liquids are based in the imidazolium cation containing a functionalization in the alkyl side chain. The chosen anions were the bis(trifluorosulfonyl)imide, [NTf2], the dicyanamide, [DCA] and the methylphosphite, [C1HPO3]. Several parameters were taken into account for this primary evaluation, such as measurements of density, viscosity and absorption of each gas in the ionic liquids, since an ideal separation solvent should have a high absorption capacity and gas selectivity, low viscosity, high thermal stability and fast absorption kinetics for the selected gas. The absorption of the 2 gases in the pure ionic liquids and ionic liquid + metallic salt solutions was measured in the temperature range between 303.15 K and 353.15 K and for pressures close to atmospheric. The ideal selectivity of the ionic liquid for the absorption of ethane compared to ethene was determined. The determination of the gas solubility in function of the temperature allowed access to the thermodynamic properties of solvation of the gases in the ionic liquids, and a deeper understanding of the gas-ionic liquid interactions and the structure of the solution

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.<p><p>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-<p>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.<p><p>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.<p><p>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

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The goal of this thesis is to design a heating system for a building of an elementary school in Polešovice. The thesis is divided into three parts. The first, theoretical, part discusses heat pumps with the main focus on gas absorption heat pumps. The se-cond part addresses the design of the school heating as well as the design of an ecological heat source. The part consisting calculations introduces the calculation of heat losses, the optimal choice of temperature gradient, the design of heating surfaces, the design of heat sources including the design of the bivalent source, the way of hot water preparation, dimensioning, the security equipment and other calculations. The last part deals with the drawing documentation, the technical report and also some economical questions such as return on investment based on measured efficiency of the heat source.