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Kren, Christoph. "Flue gas fired absorption chillers." kostenfrei, 2008. https://mediatum2.ub.tum.de/node?id=965968.
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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.
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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.
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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.
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Lee, Jessy Ju Lian. "Process intensification of nitrous gas absorption." Thesis, The University of Sydney, 2012. http://hdl.handle.net/2123/15618.
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The absorption of nitrogen oxides in water has important applications in nitric acid manufacture and pollution control. The design for optimum absorption efficiency and air pollution control has made necessary the installation of large reaction chambers and absorption towers for the adequate oxidation and absorption of nitrous gases. The worldwide production of weak acid has seen the progression of the process from the use of low through medium- to high-pressure technology in the efforts of achieving a more compact construction and avoiding the need for catalytic tail-gas treatment in plants with ever increasing capacities. Even at high pressures (8 bar), absorption columns employing sieve plates can reach up to 40 m in height for large-tonnage plants, and the relatively large pressure drop across the plates at these pressures leads to high power consumption and increased costs. As the dimensions of the absorption tower are typically governed by the conditions required for NO oxidation and thermal design, intensification of the process via miniaturisation can address the issues above through the high surface area to volume ratio offered by microreactor technology. The substantial improvement in heat and mass transfer due to the increase in effective exchange surface leads to an acceleration of the slow NO oxidation reaction and the enhancement of absorption rates. In addition to the development of such novel equipment for process intensification, the flow of the process can also be structured to improve process efficiency. An interesting method would be the replacement of the nitrogen ballast typically used in industry with steam, as the concentration of the gases upon condensation can lead to improved gas phase reaction rates. Furthermore, the provision of increased residence times due to the decrease in gas velocity upon condensation also makes the process more efficient. In this way, the size of the absorber can be significantly reduced and the high capital and operating costs associated with the employment of compressors in high pressure plants can be reduced. The objective of this thesis is to gain a fundamental understanding of the complex behaviour of nitric acid production in microchannels and obtain data for the development of a model used for process design and optimisation. Experiments on the oxidation and absorption of xviii nitrogen oxides have been conducted for a wide range of nominal residence times (0.03 – 1.4 s), gas compositions (5 – 10% NO, 5 – 49% O2, 46 – 82% H2O, balance argon), system pressures (2 – 10 bar absolute), mass fluxes (1.5 – 30 kg m-2 s-1), coolant mass fluxes (66 kg m-2 s-1 and 341 kg m-2 s-1), and coolant temperatures (23 – 51ºC) in circular tubes with internal diameters of 1.4 and 3.9 mm. Absorption efficiencies of up to 99% have been achieved without the use of counter-current flow typically employed in conventional nitric acid plants. The use high steam fractions was shown to cause significant improvements in gas phase reaction rates such that the usual industrial practice of applying high system pressures to enhance the NO oxidation reaction becomes unnecessary. Absorption efficiency can also be increased by increasing system pressures, but there are certain limits to which this can be done; a decline in performance may result when pressures are increased sufficiently high such that mass transfer becomes limiting. In addition to decreasing the tube diameter, increasing both the NO concentration and cooling duty also led to improved nitric acid yields. A simple model of condensing two-phase shear-driven annular flows, in which both laminar and turbulent regimes are valid and the vapour-liquid interface is assumed to be smooth, have been constructed and compared against experimental data. The model qualitatively captures most of the effects observed, but the presence of uncertainties in model parameters and the use of particular assumptions on the flow pattern and structure of the interface had to be compensated for through the use of a model fitted parameter iAθ. Larger corrections to the model were required in cases where the fluid was tending towards slug or plug flow, such as systems employing high H2O/NO ratios, since the interfacial area between vapour and liquid would be larger than that obtained if annular flow was assumed to occur under the same conditions. Higher values of iAθwere also found to give better fit to the experimental data at short nominal residence times (< 0.10 s) for absorption carried out under high system pressures, high oxygen partial pressures or high NO partial pressures, presumably due to incorrect representation of the overall heat and mass transfer flux under these conditions, among other things such as the parameter uncertainties, the presence of interfacial waves and the possibility of a flow regime transition from annular to intermittent flow. On the other hand, interfacial area multipliers less than unity were better suited to larger xix channels due to the possibility of flow stratification which acts to decrease the interfacial area and hence the nitric acid yield. The predictions of the model were subsequently used to determine the operating conditions optimal for the production of nitric acid in microreactors on a larger scale. In most of the cases considered, the pressure drop across the absorber length was found to be relatively small, hence much smaller channels can be utilised for increased absorption efficiency without considerable loss in pressure. It was also shown that most of the heat liberated near the inlet of the absorber stems from the release of latent heat of condensation, while chemical reactions account for most of the heat released downstream of the reactor. The absorption volume required for the commercial production of nitric acid in microchannels was compared against that typically employed by current industrial absorbers. The volume of the microreactor system was found to be about 2 orders of magnitude smaller than its larger counterpart. Although additional volume may be required for distillation of the weaker acid produced from the smaller system, substantial reduction in plant size can still be achieved since the volume of the cooler-condenser was excluded from the industrial plant calculations while the physical and chemical reactions involved in the cooler-condenser are already inherent in the microreactor system. In summary, the results of the experiments and model simulations have demonstrated that the absorption of nitrous gases in microchannels with the use of a steam ballast and close-to-stoichiometric quantities of oxygen can lead to intensification of the process, thus presenting an opportunity for a paradigm shift in nitric acid production.
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Cottet, Aurelien. "Acoustic absorption measurements for characterisation of gas mixing." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/12428.
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Thornton, Lee James. "Diode laser absorption studies of gas phase species." Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:5119b209-f6ee-4525-8d01-36276eaa30a5.
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Sensitive and selective absorption spectroscopy techniques are applied to the detection of the excited species present in a range of low pressure inductively coupled plasmas (ICPs). The state densities and temperatures of various species are investigated across the parameter space accessible (plasma power and pressure) to aid in the understanding of the kinetic processes occurring. The experimental methods are based upon various forms of absorption spectroscopy, incorporating wavelength modulation and/or an optical enhancement cavity. The probing radiation is generated either directly using a CW diode laser or indirectly through the use of frequency conversion techniques. The absolute number densities of all four levels (1s2, 1s3, 1s4 and 1s5) present in the first excited manifold of atomic argon and neon are determined as a function of plasma operating conditions. A kinetic model is constructed to simulate these populations using cross-sections taken from the literature together with further measurements on the electron density and temperature obtained with a Langmuir probe. The model elucidates the importance of populational redistribution within the 1s manifold via excitation to the 2pn levels, and highlights the mechanism of radiative decay (with radiative trapping taken into account) as the ultimate loss route for the 1s manifold. Measurements are made using cavity enhanced absorption spectroscopy (CEAS) on the 2p5 and 2p6 state densities in argon in order to draw additional conclusions about the nature of the discharge and to verify the kinetic model. The populations of the 1s3 and 1s4 states are probed in a neon plasma with helium, argon and nitrogen as a dopant gas, with the aim of manipulating the EEDFs. The addition of N2 and Ar to the neon discharge resulted in a reduction in the 1s3 and 1s4 populations, while the addition of He resulted in an increase. These observations are consistent with a decrease and an increase, respectively, in the electron temperatures. The populations of the vibrational levels v = 0, 1, 3, and 6 of the A(3Σu+) state of molecular nitrogen are determined as a function of plasma operating conditions in a N2 discharge using CEAS. A selection of vibrational bands within the B(3Πg)←A(3Σu+) system are probed, with calibration achieved using cavity ring-down spectroscopy. At 25 mTorr and 200 W power the populations of the v = 0, 1,3, and 6 levels are (1.31 ± 0.16) × 1011 cm-3, (8.44 ± 1.01) × 1010 cm-3, (2.83 ± 0.34) × 1010 cm-3 and (5.27 ± 0.63) × 109 cm-3, respectively, corresponding to a vibrational temperature of 3600 ± 150 K. In addition, the observation of the N2+(X2Σg+) molecular ion in v = 0 using both CEAS and CEAS in combination with wavelength modulation spectroscopy is presented (which is found to improve the sensitivity for this measurement by approximately an order of magnitude). At 10 mTorr and 400 W the total population in N2+(X2Σg+, v = 0) is (1.26 ± 0.15) × 109 molecules cm-3, consistent with data obtained using a Langmuir probe. The density of oxygen atoms present in their ground state (3P2) is investigated using the technique of CEAS, and at 500 W and 100 mTorr the concentration is estimated to be (2.2 ± 0.3) × 1014 cm-3. This corresponds to a dissociation efficiency, δ, of O2 of 0.06. Furthermore, a difference frequency generation (DFG) system is constructed to generate radiation at 1.9 μm in order to probe the (0,0) band of the O2(b1Σg+←a1Δg) quadrupolar system. A minimum detectable absorbance of 1.3 × 10-5 over a 10 cm cell is determined by calibrating the system on an ammonia absorption, placing a limit of 1.8 × 1016 cm-3 on the total v = 0 population of O2(a1Δg) in a microwave discharge operating with 5 Torr pure O2.
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Foo, James. "Laser absorption spectroscopy and tomography of gas flows." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/laser-absorption-spectroscopy-and-tomography-of-gas-flows(47a30c34-4290-4b28-bcb4-bbfa94cc5859).html.
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This research focuses on developing optical sensing systems for 2D and 3D spatial monitoring of temperature and concentration distribution profiles of complex or reacting gas flows. Non-invasive, species specific and sensitive nature of monitoring allows spatial information to be extracted from harsh environments with poor physical access, allowing validation of computational models or process monitoring. This is suitable for processes like combustion engines or sealed atmospheric cloud chambers. A novel line-of-sight (LOS) Tunable Diode Laser Absorption Spectroscopy(TDLAS) system using a preselected laser diode centred at 7212.88 cm-1 was first designed to monitor the change of relative humidity (water vapour concentration) during an expansion process within the Manchester Ice Cloud Chamber (MICC), operating from atmospheric pressure, down to 0.7 atm. The experimental results were validated with an Aerosol Cloud Precipitation Interaction Model (ACPIM) simulation, feasible for tomography applications. The MICC shares similar combustion monitoring challenges such as minimal optical access or reactive gas flows. The TDLAS system developed for the MICC was then used as a foundation design for a TDLAS tomography setup capable of conducting temporal two-dimensional (2D) and three-dimensional (3D) concentration and temperature imaging. This system uses the principle of two-line thermometry, centred within the near infrared (NIR) region of 7181.93cm-1 and 7179.8 cm-1. The laser was divided into 4 simultaneous parallel beams using a 1 × 4 fiber coupler (4 LOS). Using a motorised platform, the beams were projected at 0.5° interval, from 0° to 179° angle within 3.6 s, around the exhaust of two asymmetrical shaped flame burners. A total of 360 projection slices comprised of 1440 integrated absorbance data were used per tomogram reconstruction. By solving for the spatial distribution of temperature first, the concentration distribution of water vapour could be then calculated. Reconstruction algorithms (Filtered Back Projection, Fourier Slice Reconstruction and Direct Fourier Reconstruction (DFR)) were compared using a range of criteria. The DFR method was selected as the best method at 700 zero padding, with a spatial in-plane resolution of 1-2 lp/cm, pixel resolution of 128 by 128, thermocouple temperature validations of ±5°C and a relative mean error performance of 8.12%. The concentration could not be validated due to the lack of a mass spectrometer.3D volumetric monitoring results took 36 seconds to complete, and was constructed using 10 interpolated parallel, 1 cm height interval spaced tomograms. Independent vertical slices along the x-axis and y-axis could also be extracted. The temporal results were also successfully conducted and consisted of a quick succession of 16 experiments at a temporal resolution of 0.28 frames per second. A tomographic system that performs 3D and 2D temporal sensing was successfully developed and validated. Although 3D work was conducted using planar imaging or hyperspectral tomography, no work has been conducted so far using NIR TDLAS systems to date.
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Hekimat-Nazemi, Ali. "Gas absorption in mobile beds of spherical packings." Thesis, University of Leeds, 1992. http://etheses.whiterose.ac.uk/8884/.
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Experiments have been conducted to investigate the hydrodynamics and mass transfer performance of some alternative mobile bed packings. The polypropylene packings used in this work were 50 x 38 mm oblate spheroids, 38 mm diameter plain spheres, 25 mm diameter plain spheres and 25 mm diameter slotted spheres. The perspex column was 22 cm internal diameter and 144 cm high and was fitted with a supporting grid having 72% open area. In the hydrodynamics studies, air and water were passed counter currently through the column. Bed pressure drop, mean expanded bed height, minimum expanding gas velocity and volume of liquid hold up for all of the packings were measured at different air and water rates and with two bed static heights of 10.5 and 16.5 cm. The general hydrodynamic behaviour of the fluidized packings has been observed and factors influencing pressure drop, liquid hold up, expanded bed height and minimum expanding velocity have been identified. Evidence for gas and liquid flow through the interiors of the slotted packings and giving rise to higher liquid hold up and a smoother quality of fluidization as compared with the other packings has been found. Plain spheres and oblate spheroid packings appeared to have almost identical hydrodynamic behaviour, although the oblate spheroid was found to show more slugging fluctuation in the bed height at high gas veloci ti e s . In mass transfer studies, dilute C02 (2% voV Vol) was absorbed into sodium hydroxide solutions and the interfacial area and liquid film transfer coefficient were thereby established employing the pseudo first order reaction model for the rate of absorption (known generally as the Danckwerts' model) (41). The experimental results on the Danckwerts' plot lay on a straight line and therefore confirmed the applicability of the Danckwerts' model from which (kL) and (a) could be estimated. The interfacial area per unit volume of expanded bed (a) and per unit volume static bed (as) was found to be higher for the slotted packings than for the plain sphere packings and the oblate spheroid packi ngs. The interfacial area per unit volume of liquid hold up (aL) was higher for the plain sphere packing than for the oblate spheroid and the slotted sphere packings, however, the (a) and (as) for the plain sphere packings were higher than for the oblate spheroid packings. The liquid film transfer coefficient for the slotted sphere packings was higher than for the other packings and was found to be almost the same for the plain sphere and the oblate spheroid packings. The operational mass transfer efficiency (defined as the ratio of the volumetric liquid film mass transfer coefficient to the fluid energy consumption in the bed) for the oblate spheroid packings was found to be higher than for the plain and slotted sphere packings. This efficiency ratio was also found to be higher for the slotted packings than for the plain sphere packings. Finally, the slotted packings appear to offer high volumetric mass transfer coefficients with a smoother quality of fluidization and homogeneous contacting of gas and liquid.
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Thompson, Alexander W. J. "Multimode absorption spectroscopy of CO and CO₂ gas mixtures." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:ebcb2031-1165-414e-88d8-69465bdaf291.
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The development of multimode absorption spectroscopy (MUMAS) for multi-species detec- tion and its potential for process control or environmental monitoring is reported. The simultaneous detection of CO and CO2 is demonstrated in a proof-of-principle experiment for applications in industrially relevant gas species monitoring. The technique of MUMAS is extended to the near infrared in order to detect these and other industrially relevant species. A laser was designed and constructed to emit a multimode spectrum in the region of 1.57um to take advantage of the spectral overlap of the second vibrational overtone of CO and the combination band 3ν1 + ν3 of CO2. The laser consisted of a semi-confocal cavity employing an Er:Yb glass chip as the gain medium. The laser was pumped by a 1W laser diode at 980nm and emitted up to 30mW in a bandwidth of 180GHz. The laser emitted between 6-10 modes depending upon the selective cavity length. Mode spacings varied between 18GHz to 33GHz with an individual mode linewidth of less than 8MHz. The laser modes were simultaneously scanned using a piezo-electric transducer (PZT) in order to modulate the cavity length at frequencies between 1Hz and 10Hz. A system for linearizing the MUMAS spectra with respect to frequency was devised based on a transmission spectra of a confocal Fabry-Perot etalon. Refinements to the MUMAS fitting code were developed to improve the computational efficiency. An initial demonstration of MUMAS on a known gas mixture of CO and CO2 was per- formed. The ratio of CO:CO2 concentrations in the gas mixture was measured with an accuracy of 0.4% which was within the supplier’s quoted uncertainty. MUMAS is then applied to the detection of CO and CO2 concentrations in exhaust gas produced by a 1.3 litre 4-cylinder turbo-charged spark ignition engine. Relative and absolute concentrations were derived from MUMAS signals and values compared to measurements using a 4-gas analyser. Concentrations of CO and CO2 were measured using MUMAS to a precision of 0.17% and 0.23% respectively compared to less than 0.1% for the 4-gas analyser. Ratios of CO and CO2 were determined with a precision of 0.28 using MUMAS compared to 0.11 with the 4-gas analyser. The detection limit of CO was found to be 1486ppm in these circumstances. Finally a discussion is presented of potential improvements arising from wavelength mod- ulation spectroscopy and cavity enhancement techniques.
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Martin, Margarita. "Synthesis of heat integrated gas separation systems incorporating absorption." Thesis, University of Manchester, 2009. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:228857.
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There is an economic incentive to substitute energy and capital-intensive conventional gas separation schemes based on cryogenic distillation. Absorption has potential advantages over low-temperature schemes as it does not rely on high refrigeration requirements to perform the separation. An optimisation-based synthesis framework has been developed that integrates distillation and absorption-desorption schemes. This methodology is able to quantitatively resolve the numerous tradeoffs between the various capital and operating factors and systematically suggest new design configurations. A multilevel modelling approach enables the accommodation of absorption-desorption separation options in the distillation orientated framework supported by COLOM® (©Centre for Process Integration, University of Manchester). Improved shortcut models for reboiled absorption and distillation columns have been proposed, which are suitable for exploitation in the developed synthesis framework. A new methodology for heat integration is proposed that achieves efficient heat recovery and proposes a configuration of the heat exchanger network. This methodology works in harmony with the optimisation framework. Simultaneous optimisation of the separation system, the heat exchanger network and the refrigeration system offers the opportunity of achieving a superior overall configuration. The structural and operating variables of the separation system are optimised by Simulated Annealing. As a stochastic optimisation method, SA can deal with the large scale of the problem and its discontinuous and non-linear nature imposed by the feasibility limits of the separations and the model equations. The optimal separation configurations are selected on the grounds of minimum capital and operating costs. An analysis of costing methods is provided which aims at rationalising the basis for cost estimation. The application of the developed synthesis methodology is illustrated by a number of examples of relevance to the natural gas processing and refinery gas processing. Results will emphasise the functionality of the methodology as a tool for quantitative evaluation of preliminary designs and realisation of highly integrated and efficient process concepts.
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Betelmal, Entesar Hassan. "Thermo-economic study of gas turbine-absorption cogeneration cycle." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417545.
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Bobrowski, Nicole. "Volcanic gas studies by Multi Axis Differential Absorption Spectroscopy." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:16-opus-60521.
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Hirst, G. "Ionic species in gas lasers." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379854.
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Bass, Stephen Frank. "Optical properties of laboratory-generated polar stratospheric cloud particles." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275366.
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Ngo, Thanh Hai [Verfasser], and Adrian [Akademischer Betreuer] Schumpe. "Gas absorption into emulsions / Thanh Hai Ngo ; Betreuer: Adrian Schumpe." Braunschweig : Technische Universität Braunschweig, 2013. http://d-nb.info/1175822965/34.
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Tütüncü, Erhan [Verfasser]. "Miniaturized gas sensors based on laser absorption spectroscopy / Erhan Tütüncü." Ulm : Universität Ulm, 2019. http://d-nb.info/1200470060/34.
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Liu, Zhuan. "Infrared diode laser absorption spectroscopy of gas phase molecular ions." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627231.
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Vigstrand, Oscar. "Development of an absorption model for gas discharge lamp simulation." Thesis, Malmö universitet, Malmö högskola, Institutionen för materialvetenskap och tillämpad matematik (MTM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-42518.
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Ultraviolet (UV) light has been used for disinfection purposes for over 100 years. Irradiation by UV light is a method to disinfect surfaces in order to prevent microbiological growth. At Tetra Pak this is of great importance as they are manufacturer of filling machines. Those filling machines must ensure a certain level of sterility on all packages produced. The irradiation process can be simulated using Geant4 which is a software package that tracks particles through matter. The simulation model used today does not consider the absorption of photons inside of medium-pressure UV lamps. By understanding the absorption that takes place in the lamp, one can quantify how changes in the design would impact the emitter output. In this master's thesis, the aim is to develop a model that can describe the interaction of photons with a medium-pressure UV lamp. An absorption model was suggested and developed with the assumption of local thermodynamical equilibrium and existing Hg radiative data. A simulation including the collision process in Geant4 was used. In this collision process the non-radiative transition probabilities were assumed to be the same as that of the radiative, this was done in order to demonstrate how it can be done. It resulted in collisions populating other states allowing more transitions to be present in the final output spectrum. The collision process and a method for computing the Einstein's emission coefficient with the software package General Relativistic Atomic Structure Package is proposed as future work.I över 100 år har ultraviolet (UV) ljus använts till desinficering. UV bestrålning är en metod för att desinficera ytor med målet att förhindra mikrobiologisk tillväxt. För Tetra Pak som är ledande inom tillverkning av fyllmaskiner är det extra viktigt. Förpackningarna inuti fyllningsmaskinerna måste garantera en viss nivå av sterilitet för alla förpackningar. Dagens simuleringar av medeltrycks UV lampa utförs i Geant4 som är ett mjukvarupaket som möjliggör följandet av partiklar genom olika medium. Detta görs utan att ta hänsyn till absorptionen av fotoner. Genom att förstå absorptionen som sker i lampans gas kan man kvantifiera hur förändringar i design skulle påverka emittorns utgående effekt. I detta examensarbete är målet att utveckla en modell som kan beskriva hur fotoner växelverkar med gasen i en medeltrycks UV lampa. En modell utvecklas och föreslås med antagandet att lokalt termodynamisk jämvikt råder och att enbart Hg strålnings data används. En simulering med en kollisionsprocess i Geant4 inkluderades. I denna kollisionsprocess antas den icke-optiska övergångssannolikheten vara densamma som för de optiska övergångarna. Detta inkluderades för att demonstrera hur en sådan process kan gå till. Detta resulterade i att kollisionerna populerade andra tillstånd vilket gjorde att dessa övergångar visade sig i utgående spektrum. Kollisionsprocessen och en metod för att beräkna Einsteins emissions koefficient med mjukvarupaketet General Relativistic Atomic Structure Package föreslås även som framtida arbete.
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Aliwell, Simon Richard. "Measurement of atmospheric trace gases by absorption spectroscopy." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388668.
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Stewart, Lloyd Dorton. "Gas turbine inlet duct air temperature measurement using CO[subscript]2 infrared absorption." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/17367.
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Putkham, Apipong. "Synthesis, characterisation and gas absorption studies for metal organic framework materials." Thesis, University of Newcastle Upon Tyne, 2010. http://hdl.handle.net/10443/909.
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Recently, porous metal organic framework materials (MOFs) have attracted considerable attention due to the wide range of possible applications of the materials in 1) gas storage, purification and separation; 2) as catalysts and catalyst supports; and 3) for adsorption of environmentally unfriendly species. This study has involved the synthesis, characterisation and determination of the adsorption/desorption characteristics of functionalised porous metal organic framework materials. The overall objective was to increase understanding of the role of surface functional groups and framework flexibility in determining the adsorption characteristics of gases and vapours and assess the possible applications of these materials for gas storage and separation. Adsorption of hydrogen, nitrogen, oxygen and argon were studied in order to investigate the possible applications of metal organic framework NEW-1 in gas storage and air separation. In case of the air separation, adsorption characteristics of O2, N2, and Ar on metal organic framework NEW-1, mixed-zinc/copper organic framework (M’MOF-1) and a carbon based molecular sieve (CMS-40) were compared. The crucial factors such as molecular size and shape in relation to pore structure in determining the adsorption characteristics on materials were investigated. Selected kinetic models i.e. stretched exponential model (SE), double stretched exponential model (DSE) were used to determine the kinetic adsorption parameters. Also, the isosteric enthalpies of gases adsorption at zero surface coverage were determined. The results show that very narrow pores are required in metal organic frameworks to achieve kinetic selectivity similar to CMS-40.
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Howieson, Iain Fletcher. "Near-infrared tunable diode laser absorption spectrometer for trace gas detection." Thesis, University of Strathclyde, 1997. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21396.
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A ground based near-infrared tunable diode laser absorption spectrometer (TDLAS), capable of measuring methane (CH₄) and nitrous oxide (N₂0) in their natural abundance's within the atmosphere, has been designed and constructed. The spectrometer has high resolution (0.0003 cm⁻¹), high precision (equivalent to a minimum detectable absorption of ~2 x 10⁻⁷) and uses the latest developments in near-infrared t echnology to provide similar sensitivities to mid-infrared laser spectrometers. A theoretical analysis of the noise performance of different detection schemes has been performed. It was concluded that near optimum performance could be achieved using second harmonic wavelength modulation spectroscopy in the 50-100k Hz region. Instrument sensitivity was enhanced through the use of a Herriott multipass cell. A computer model of the behaviour of a paraxial ray passing through such a cell has been developed, allowing suitable choice of cell design and spot pattern to be made. The model was modified to allow the behaviour of an astigmatic Herriott cell to be investigated. The model has shown that the astigmatic cell has all the inherent stability properties of the conventional cell. An astigmatic cell capable of supporting a 100 m pathlength in a2 litre mode volume was designed, built and tested. Performance assessment of the spectrometer was carried out. Detection limits equivalent to 560 pptV of methane and 22 ppbV of nitrous oxide were obtained. A field test and intercomparison with methane monitors (Flame Ionisation Detectors), showed that the retrieved concentrations from the spectrometer agreed to within the measurement uncertainty of the other instruments. Laboratory support for high resolution spectroscopic measurements of gases of atmospheric interest, including, methane, nitrous oxide and ammonia has been carried out. A rotational analysis of nitrous oxide was performed. A coolable Herriott cell capable of operating between 77 and 298 K has been designed, built and tested.
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Purba, Elida. "Gas absorption in a spray tower using axial and swirling flows." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405793.
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Martín, Ortega Álvaro. "Power absorption mechanisms and energy transfer in X-ray gas attenuators." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY006/document.
Full textAbstract:
Le travail effectué dans le cadre de cette thèse porte sur l'étude d'un atténuateur de rayonnement X à gaz et du plasma produit à l'intérieur. Un atténuateur à gaz est composé d'une chambre remplie du gaz, généralement argon ou krypton à quelques centaines de millibars, qui absorbe la partie de basse énergie d'un spectre de rayonnement X de synchrotron, en réduisant la puissance reçu par les éléments optiques en aval sans affecter les propriétés de la partie de haute énergie du spectre. L'absorption des photons crée une région de gaz chaud et ionisé autour du parcours du faisceau X, en réduisant la densité du gaz localement. A détaillé bilan énergétique entre tous les processus impliqués c'est nécessaire pour être capable de prédire l'absorption et opérer et dessiner atténuateurs a gaz efficacement. Un modèle hybride que combine techniques de modélisation Monte Carlo et fluides à été développé pour déterminer le bilan énergétique et simuler l'absorption de rayonnement X. Le modèle a été valide expérimentalement pas études incluant absorption de puissance, spectroscopie optique d'émission et spectroscopie d'absorption par laser à diodes. Les résultats des simulation et expériences montre un plasma confiné autour du parcours du faisceau X, recombinant dans le volume de gaz et avec une température maximale de plusieurs centaines de Kelvin. Le modèle a été capable de prédire l'absorption de rayons X avec un erreur de entre 10 et 20%, qui permettre son utilisation comme première approximation pour le dessin et opération de atténuateurs a gaz et aussi comme point de partie pour modèles plus affinéesThe work done in the context of this thesis focuses in the study of an X-ray gas attenuator and the plasma produced within. An X-ray gas attenuator consists on a vessel filled with gas, usually argon or krypton at a few hundreds millibars, that absorbs the low energy fraction of a synchrotron X-ray spectrum, reducing the power received by downstream optical elements without affecting the properties of the high energy part of the spectrum. The absorption of the photons creates a region of hot, ionized gas around the X-ray beam path, decreasing locally the gas density. A detailed energy balance between all the involved processes is required to be able to predict the absorption and operate and design gas attenuators efficiently. A hybrid model combining Monte Carlo and fluid modelling techniques has been developed to determine the energy balance and simulate the X-ray absorption. The model has been validated by experimental studies including power absorption, optical emission spectroscopy and tunable laser absorption spectroscopy. The results of both simulation and experiments show a plasma confined around the X-ray beam path, recombining in the bulk of the gas and with a maximum temperature of several hundreds of Kelvin. The model was able to predict the X-ray absorption within a 10-20% of error, which allows its use as a first approximation for the design and operation of gas attenuators, and also provides a starting point for more refined models
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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 textAbstract:
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.
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Reeves, Sarah Natasha. "HI emission and absorption-line studies of nearby, gas-rich galaxies." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16556.
Full textAbstract:
HI absorption-line studies provide a unique insight into the growth and evolution of galaxies. Next-generation radio telescopes will allow us to conduct the first large, blind absorption-line surveys, studying the evolution of neutral gas at redshifts that are currently largely unexplored. In this thesis, we have conducted a detailed study of HI emission and absorption in nearby galaxies to investigate the expected detection rate of intervening absorption in future surveys and how various factors influence this detection rate. We conducted a survey for intervening absorption using new ATCA observations. 23 sightlines, with impact parameters of 6-46kpc were searched for absorption, resulting in one new detection (a detection rate of 4.3%). Our detection rate is significantly lower than in previous studies, but as our selection criteria much more closely match that of future blind surveys, this suggests our results are far more representative of the true detection rate. We also find that the structure of the background radio sources significantly affects the detection rate, with many sources having complex structures which dramatically reduces the absorption-line sensitivity. In a separate study, we applied the technique of HI spectral stacking to search, for the first time, for a signal of intervening absorption in HIPASS. In particular, we were interested in searching for absorption at impact parameters to large (<100-200kpc) to detect in individual observations. While the presence of HI emission limits the interpretation of our results, we do see possible evidence of absorption at impact parameters <60kpc, and our analysis clearly demonstrates the potential of this new technique to search for weak absorption-line signals in the outskirts of galaxies. Combined, the results in this thesis advance our understanding of the conditions in which intervening absorption arises, and provide important information in the preparation for future large absorption-line surveys.
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D'Odorico, Valentina. "Quasar Absorption Spectra: Probes of the Baryonic Gas at High Redshift." Doctoral thesis, SISSA, 1999. http://hdl.handle.net/20.500.11767/4375.
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Goodman, D. A. "X-ray absorption spectroscopy of dense, shock compressed, laser plasma." Thesis, University of Essex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303516.
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Dowson, A. L. "Some aspects of hydrogen absorption and hydrogen embrittlement in alpha titanium." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382542.
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Gaedke, Ansgar [Verfasser]. "Development Of A Gas Absorption Cell For The Near-Infrared / Ansgar Gaedke." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2009. http://d-nb.info/1036913678/34.
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McEnaney, Kevin Bernard. "Magneto-absorption of surface acoustic waves by a 2-dimensional electron gas." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293651.
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Baker, N. S. "A new strategy for selecting and evaluating physical solvents for gas absorption." Thesis, Aston University, 1994. http://publications.aston.ac.uk/9759/.
Full textAbstract:
This work describes how the physical properties of a solvent affect the design variables of a physical gas absorption process. The role of every property in determining the capital and the running cost of a process has been specified. Direct mathematical relationships have been formulated between every item of capital or running cost and the properties which are related to that item. The accuracy of the equations formulated has been checked by comparing their outcome with some actual design data. A good agreement has been found. The equations formulated may be used to evaluate on the basis of economics any suggested new solvents. A group of solvents were selected for evaluation. Their physical properties were estimated or collected as experimental data. The selected ones include three important solvents, the first is polyethylene glycol dimethyl ether (Selexol) which represents the currently most successful one, The other two solvents are acetonyl acetone (B2) and n-formyl morpholine which have been suggested previously as potential credible alternatives to the current ones. The important characteristics of: acetonyl acetone are its high solubility and its low viscosity, while the n-formyl morpholine is characterised by its low vapour pressure and its high selectivity. It was found that acetonyl acetone (B2) is the most attractive solvent for commercial applications particularly for process configurations that:include heat exchangers and strippers. The effect of the process configuration on the selected solvent was investigated in detail and it was found that there is no universal solvent which is the best for any process configuration, but that there is a best solvent for a given process configuration. In previous work, acetonyl acetone was suggested as a commercially promising physical solvent. That suggestion was not fully based on experimental measurement of all the physical properties. The viscosity of acetonyl acetone and its solubility at 1 atm were measured but the vapour pressure and the solubility of C02 and CH4 at high pressure were predicted. In this work, the solubilities of C02, CH4 and C3H8 in acetenyl acetone were measured for a partial pressure range of (2 ~ 22) bar at 25°C, The vapour pressure of this solvent was also measured, and the Antoine equation was formulated from tbe experimental data. The experimental data were found to be not In agreement with the predicted ones, so acetonyl acetone was re-evaluated according to the experimental data. It was found that this solvent can be recommended for further trials in a pilot plant study or for small scale commercial units.
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Zou, Siwei. "Using quasar absorption lines to probe cold gas in high redshift galaxies." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS181/document.
Full textAbstract:
Les raies d'absorption de quasars sont des outils efficaces pour étudier le milieu interstellaire dans les galaxies. Dans ce travail, nous étudions un échantillon de soixante-six systèmes absorbants à z<1.5 sélectionnés pour la présence de raies d'absorption de CI intenses dans leurs spectres SDSS. Ils sont observés par les spectrographes X-shooter et UVES du VLT de l'ESO. Nous étudions en tout 17 systèmes observés par X-shooter. Nous déduisons la métallicité, la déplétion par la poussière, le taux d'extinction par la poussière et le taux d'absorption des raies de MgII, MgI, CaII et NaI décalées dans l'infrarouge proche. Nous détectons neuf raies d'absorption de CaII avec W(CaII λ3934)>0.23Å. Nous détectons dix raies d'absorption de NaI dans quatorze systèmes susceptibles d'en montrer. La largeur équivalente médiane de W(NaI λ5891)=0.68Å est plus grande que celles observées dans des nuages proches ayant des densités-colonnes de HI similaires ou dans des systèmes CaII à z<0.7 détectés par le SDSS. La présence systématique de raies d'absorption de NaI dans ces systèmes CI suggère fortement que le gaz environnant est neutre et froid, et donc peut faire partie du gaz moléculaire diffus dans le milieu interstellaire de galaxies à fort décalage vers le rouge. Les raies d'absorption de MgII s'étalent sur plus de 400km/s en Δv pour la moitié de l'échantillon; trois systèmes ont un Δv supérieur à 500 km/s. Tout ceci suggère qu'une fraction importante du gaz froid à fort décalage vers le rouge émane d'environnements perturbés. Nous détectons de l'hydrogène moléculaire dans tous les systèmes dans la limite de détectionQuasar absorption lines are a powerful tool to study the interstellar medium(ISM) in the galaxies. We study a sample of 66 z >1.5 absorbers selected based on the presence of strong CI absorption lines in SDSS spectra and observed with the ESO-VLT spectrograph X-shooter/UVES. I study 17 systems that are re-observed by X-shooter. I derive metallicities, depletion onto dust, extinction by dust and analyse the absorption from MgII, MgI, CaII and NaI that are redshifted into the near infrared wavelength range. I detect 9 CaII absorptions with W(CaII λ3934) > 0.23 Å out of 14 systems. I detect 10 NaI absorptions in the 11 systems where we could observe this absorption. The median equivalent width (W(NaI λ5891) = 0.68 Å) is larger than what is observed in local clouds with similar HI column densities but also in z<0.7 CaII systems detected in the SDSS. The systematic presence of NaI absorption in these CI systems strongly suggests that the gas is neutral and cold, maybe part of the diffuse molecular gas in the ISM of high-redshift galaxies. The MgII absorptions are spread over more than Δv ~ 400 km/s for half of the systems; three absorbers have Δv > 500 km/s. The kinematics is strongly perturbed for most of these systems which probably do not arise in quiet disks and must be close to regions with intense star formation activity. All this suggests that a large fraction of the cold gas at high redshift arises in disturbed environments. We detect molecular hydrogen in all the systems within the detection limit
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Brani, David M. "Improved method for determining radiation intensity using total gas emissivities." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/17811.
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Northern, Jonathen Henry. "Multi-species detection using Infrared Multi-mode Absorption Spectroscopy." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:10f3bd62-4c81-4eaf-854d-1f388af73be9.
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This thesis reports work extending the scope of a recently developed gas sensing technique, multi-mode absorption spectroscopy (MUMAS). The ability of MUMAS to simultaneously detect multiple species from a mixture is demonstrated for the first time. The technique is subsequently extended to mid-infrared wavelengths, realising large gains in sensitivity. A solid-state, multi-mode laser has been developed to provide a high-performance comb source for use with MUMAS. This in-house constructed, diode-pumped, Er/Yb:glass laser operates on 10 longitudinal modes, separated by 18 GHz and centred close to 1565 nm. The extensive development and prototyping work leading to this final laser design is described. Multi-species detection with MUMAS is reported for the first time, thus demonstrating the ability of this technique to perform multi-gas sensing using a single laser and simple detection scheme. The previously described Er/Yb multi-mode laser was used to record MUMAS signals from a sample containing CO, C2H2, and N2O. The components of the mixture were detected simultaneously by identifying multiple transitions in each of the species. Temperature- and pressure-dependent modelled spectral fits to the data were used to determine the partial pressures of each species in the mixture with an uncertainty better than +/-2%. Multi-mode radiation has been successfully generated at 3.3 μm using quasi phase matched difference frequency generation (QPM-DFG). A mid-infrared laser comb was produced by optically mixing the near-infrared, multi-mode comb produced by the previously developed Er/Yb:glass laser with the single-mode output of a Nd:YAG laser operating at 1064 nm. This multi-frequency laser source was characterised to verify performance, and subsequently used to perform proof-of-principle MUMAS measurements on the strong transitions found in this spectral region. Spectra were recorded of NH3 and CH4 both individually and as components of a mixture. A minimum detection level for this system was determined to be 4.3 μbar m-1 for CH4, a sensitivity increase of 300 over similar measurements performed in the near-IR.
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Newnham, David A. "High vibrational overtone spectroscopy." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278081.
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Hocking, Matthew James. "An advanced wide bandwidth ultrasound absorption and velocity spectrometer for industrial applications." Thesis, Keele University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319023.
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Tontiwachwuthikul, Paitoon. "New pilot plant technique for designing gas absorbers with chemical reactions." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/32182.
Full textAbstract:
Gas absorption with chemical reaction is an important unit operation in the chemical and petroleum industries for the selective removal of components from industrial gas streams. Apart from choosing absorption media, the most difficult problems facing the design engineer are the sizing and performance prediction of the absorption tower due to the scarcity of fundamental design data, especially when novel absorption media and/or packings are used.
The solubility of carbon dioxide in 2 and 3 M solutions of 2-amino-2-methyl-1-propanol (AMP), which is a newly introduced absorbent, was determined at 20, 40, 60 and 80 °C and for CO₂ partial pressures ranging from approximately 1 to 100 kPa. The results were interpreted with a modified Kent-Eisenberg model which predicted the present and previous experimental results well. The absorption capacities of AMP and monoethanolamine (MEA) solutions were also compared.
Detailed concentration and temperature measurements were reported for the absorption of carbon dioxide from air into NaOH, MEA and AMP solutions. A full-length absorber (0.1 m ID, packed with 12.7 mm Berl Saddles up to heights of 6.55 m) was used. It was operated in countercurrent mode and at 30 to 75 % flooding velocities which are typical for gas
absorber operations. The following ranges of operating conditions were employed: superficial gas flow rate 11.1 to 14.8 mol/m² s; superficial liquid flow rate 9.5 to 13.5 m³/m² h; feed CO₂ concentration 11.5 to 19.8 %; total absorbent concentration 1.2 to 3.8 kmol/m³; liquid feed temperature 14 to 20 °C; total pressure 103 kPa. The measurements for the CO₂-NaOH and CO₂-MEA systems were compared with predictions from a previously developed mathematical model. Generally good agreement was obtained except at high CO₂ loadings of MEA solutions. Compared with MEA, AMP was found to have superior CO₂ absorption capacities and inferior mass transfer rates.
A new procedure, called the Pilot Plant Technique (PPT), for designing gas absorbers with chemical reactions has been developed. The PPT is primarily intended for designing absorbers for which fundamental design information is lacking. It is based on the premise that full-length absorption columns can be sized by making a minimum number of tests using a small-scale pilot plant. Two special features of the PPT are (i) the details of hydrodynamic parameters (i.e. mass transfer coefficients, effective interfacial area and liquid hold-up) and the physico-chemical information of the system (e.g. reaction mechanism, reaction rate constants) need not be known and (ii) complex calculations are avoided.
Using the PPT to size the height or to predict the performance of a given full-length absorber, the specific absorption rate, which is the essential information, can be measured directly using the pilot plant model (PPM) column if both columns have the same hydrodynamic conditions. This can be achieved by using the same type and size of packing in the PPM and the full-length columns and ensuring that the end and wall effects are negligible. The PPM column must also be operated at the same superficial fluid velocities as those of the full-length column. The specific absorption rate was then obtained from the gradient of the fluid composition profile along the PPM column. The validity of the PPT was demonstrated by determining the height and predicting the performance of the full-length column in which carbon dioxide was absorbed from air by aqueous solutions of NaOH and AMP at various operating conditions; good agreement was obtained.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Polyzakis, Apostolos. "Technoeconomic evaluation of trigeneraton plant: Gas turbine performance, absorption cooling and district heating." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1832.
Full textAbstract:
This PhD thesis is a demand led study taking into account changes in ambient conditions
and power settings of a tri-generation power plant. Includes an evaluation tool for
combined heat, cooling and power generation plant. The thesis is based on an overall
technical-economic analysis of the tri-generation system, including:
1. Energy demand analysis and evaluation of actual tri-generation case studies.
2. Modelling of the prime mover (Gas Turbine, GT)
3. Modelling of the absorption cooling system, (LiBr/Water).
4. Economic analysis and evaluation of the entire tri-generation plant.
Initially, the main effort is to carry out research concerning the energy demands of
different actual cases. The research includes sourcing, collecting, classification and
evaluation of the available information. The cases cover a wide range of economic life
and the resulting data specifies the energy needs which the purposed tri-generation power
plant needs to cover.
The second part deals with the prime mover (namely the Gas Turbine, GT) modelling and
simulation. The technical part of the assessment includes the Design Point (DP) and Off
Design (OD) analysis of the GT. In other words, the performance analysis simulates
different thermodynamic cycles (Simple, or with Heat Exchanger), and different
configurations (one or two shafts). Also, the computer programming code is capable of
simulating the effects of the use of different types of fuel, ambient conditions, part load
conditions, degradation, or the extraction of power for district heating or for absorption
cooling.
The third part includes the simulation of the absorption cooling system alone and/or in
co-operation with the prime mover. The simulation is based upon the premise that the
original prime mover is replaceable.
Finally, an evaluation methodology of tri-generation plants, is introduced taking into
account, both technical facts and economic data -based on certain cases from Greek
reality- helping the potential users to decide whether it is profitable to use such
technology or not. The economic scene will include the basic economic facts such as
initial cost, handling and operational cost (fuel prices, maintenance etc), using
methodology based on Net Present Value (NPV).
This thesis suggests several tri-generation technology modes. The more economic
favourable than the conventional technology is the 2-shaft simple cycle mode for the
cases of international airport (12MW total power demand) and the isolated island
(120MW), while the 1-shaft simple cycle mode is the more economic favourable for the
case of hotel (1MW).
The main contribution of the thesis is that it provides an intergraded realistic tool, which
simulates the future operation (technical and economic) of a trigeneration plant, capable
of helping the potential investor decide if it is profitable to proceed with the investment.
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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.
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Kalivoda, Josef. "Odstraňování plynných kontaminantů z atmosféry." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216676.
Full textAbstract:
The Diploma thesis is devoted to the absorption of gases by the experimental gas scrubber. The main attention of the theoretical part is focused on the description of absorption, kinetics and the equilibrium between gas and liquid phase. Experimental part is concentrated on the absorption of carbon dioxide to deionized water in the experimental scrubber. Finally, experimental data are discussed.
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Loos, Timo. "Simulation der chemischen Absorption im Strahlwäscher." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1154783674930-96048.
Full textAbstract:
Strahlwäscher sind durch Ihre Fluiddynamik gekennzeichnet, was eine detaillierte Simulation erschwert. Es konnte gezeigt werden, dass die in der Literatur üblichen empirischen Ansätze aufgrund Ihrer Vereinfachungen den Prozess nur ungenau beschreiben und daher nur für eingeschränkte Bedingungen gelten. Die für die Auslegung von Strahlwäschern relevanten Größen, die erreichbare Pressung und die Stoffaustauschfläche, für beliebige Betriebspunkte wurden in dieser Arbeit durch eine dreidimensionale CFD Simulation berechnet. Es wurden entsprechende Unterprogramme implementiert, um den Stoffübergang im Strahlwäscher zu berechnen. Die chemische Absorption wurde sowohl für die Tropfen als auch für den sich ausbildenden Wandfilm berechnet und als Senke an die Gasphase zurückgegeben. Die Tropfengröße und der Sprühwinkel haben einen essentiellen Einfluss auf die Strömungsverhältnisse im Strahlwäscher. Diese, im wesentlichen von der Düse abhängigen Größen, wurden experimentell mit der Phasen-Doppler-Anemometrie bestimmt. Die Simulationsergebnisse wurden durch Versuche in einer Technikumsanlage verifiziert.
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McCulloch, Michael Telfer. "Quantum cascade laser based absorption spectrometer for trace gas molecular detection and nonlinear optics." Thesis, University of Strathclyde, 2006. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21614.
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Polyzakis, Apostolos L. "Technoeconomic evaluation of tri-generation plant : gas turbine performance, absorption cooling and district heating." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/1832.
Full textAbstract:
This PhD thesis is a demand led study taking into account changes in ambient conditions and power settings of a tri-generation power plant. Includes an evaluation tool for combined heat, cooling and power generation plant. The thesis is based on an overall technical-economic analysis of the tri-generation system, including: 1. Energy demand analysis and evaluation of actual tri-generation case studies. 2. Modelling of the prime mover (Gas Turbine, GT) 3. Modelling of the absorption cooling system, (LiBr/Water). 4. Economic analysis and evaluation of the entire tri-generation plant. Initially, the main effort is to carry out research concerning the energy demands of different actual cases. The research includes sourcing, collecting, classification and evaluation of the available information. The cases cover a wide range of economic life and the resulting data specifies the energy needs which the purposed tri-generation power plant needs to cover. The second part deals with the prime mover (namely the Gas Turbine, GT) modelling and simulation. The technical part of the assessment includes the Design Point (DP) and Off Design (OD) analysis of the GT. In other words, the performance analysis simulates different thermodynamic cycles (Simple, or with Heat Exchanger), and different configurations (one or two shafts). Also, the computer programming code is capable of simulating the effects of the use of different types of fuel, ambient conditions, part load conditions, degradation, or the extraction of power for district heating or for absorption cooling. The third part includes the simulation of the absorption cooling system alone and/or in co-operation with the prime mover. The simulation is based upon the premise that the original prime mover is replaceable. Finally, an evaluation methodology of tri-generation plants, is introduced taking into account, both technical facts and economic data -based on certain cases from Greek reality- helping the potential users to decide whether it is profitable to use such technology or not. The economic scene will include the basic economic facts such as initial cost, handling and operational cost (fuel prices, maintenance etc), using methodology based on Net Present Value (NPV). This thesis suggests several tri-generation technology modes. The more economic favourable than the conventional technology is the 2-shaft simple cycle mode for the cases of international airport (12MW total power demand) and the isolated island (120MW), while the 1-shaft simple cycle mode is the more economic favourable for the case of hotel (1MW). The main contribution of the thesis is that it provides an intergraded realistic tool, which simulates the future operation (technical and economic) of a trigeneration plant, capable of helping the potential investor decide if it is profitable to proceed with the investment.
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Meyers, Jason. "Tunable diode laser absorption spectroscopy characterization of impulse hypervelocity CO2 flows." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210279.
Full textAbstract:
Tunable diode laser absorption spectroscopy using an external cavity diode laser operating in the infra-red has been developed to monitor CO2 in the freestream of the Longshot hypervelocity facility at the Von Karman Institute for Fluid Dynamics. The Longshot facility offers a unique European facility for ground testing and numerical validation applications, however, some of the traditional data rebuilding aspects are in question. A non-intrusive absorptionsensor could significantly aid in improving the knowledge of freestream static values thereby improving the models used in data rebuilding and numerical simulation. The design of such a sensor also expands the spectroscopic capabilities of the Von Karman Institute.
The absorption sensor is designed around the single P12 (00001)-(30013) rovibrational transition near 1.6µm (6218.09cm-1 specifically) which yields relatively weak direct absorption levels at about 3.5% per meter for typical Longshot freestream conditions. However, when handled carefully, adequate signal-to-noise can be acquired to exploit significant flow information. By being able to operate in this range, total sensor cost can be easily an a factor of two or more cheaper than sensors designed for the deeper infrared. All sensor elements were mounted to a compact portable optics bench utilizing single-mode optical fibers to allow for quick installation at different facilities by eliminating tedious optical realigning. Scans at 600Hz were performed over 20ms of the 40ms test time to extract core static temperature, pressure and velocity.
These results are compared with the current state of the Longshot data rebuild method. The non-uniform flow properties of the shear layer and test cabin rested gas accumulation was of an initial concern. The temperature and density gradients along with significant radial velocity components could result in DLAS temperature, pressure and velocity that are significantly different than that of the target freestream inviscid core values. Fortunately, with the proper selection of the P12 rotational number, this effect could be more or less ignored as the higher temperature and lower density gas of this region is relatively transparent.
Ultimately, acquired temperature and density were moderately accurate when compared to Longshot rebuilt results owing primarily to the baseline extraction which poses issues for such low absorption signals. However, the extracted velocity data are quite accurate. This is a definite puls for the sensor as the freestream enthalpy of cold hypersonic facilities is dictated primarily by the kinetic energy contribution. Being able to compare velocity gives insight to the level of vibration non-equilibrium in the flow. The velocity of the DLAS and the Longshot rebuild are quite close. This adds more weight to the argument that vibrational excitation is very low (if present at all) in the free stream and that the van de derWaals equation of state usage and constant specific heat assumption might be an adequate model for the data rebuild after all.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
46
Loos, Timo. "Simulation der chemischen Absorption im Strahlwäscher." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24856.
Full textAbstract:
Strahlwäscher sind durch Ihre Fluiddynamik gekennzeichnet, was eine detaillierte Simulation erschwert. Es konnte gezeigt werden, dass die in der Literatur üblichen empirischen Ansätze aufgrund Ihrer Vereinfachungen den Prozess nur ungenau beschreiben und daher nur für eingeschränkte Bedingungen gelten. Die für die Auslegung von Strahlwäschern relevanten Größen, die erreichbare Pressung und die Stoffaustauschfläche, für beliebige Betriebspunkte wurden in dieser Arbeit durch eine dreidimensionale CFD Simulation berechnet. Es wurden entsprechende Unterprogramme implementiert, um den Stoffübergang im Strahlwäscher zu berechnen. Die chemische Absorption wurde sowohl für die Tropfen als auch für den sich ausbildenden Wandfilm berechnet und als Senke an die Gasphase zurückgegeben. Die Tropfengröße und der Sprühwinkel haben einen essentiellen Einfluss auf die Strömungsverhältnisse im Strahlwäscher. Diese, im wesentlichen von der Düse abhängigen Größen, wurden experimentell mit der Phasen-Doppler-Anemometrie bestimmt. Die Simulationsergebnisse wurden durch Versuche in einer Technikumsanlage verifiziert.
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Lu, Yuexia. "Experimental Studies on CO2 Absorption in Hollow Fiber Membrane Contactor." Licentiate thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-9617.
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Membrane gas absorption technology is considered as one of the promising alternatives to conventional techniques for CO2 separation from the flue gas of fossil fuels combustion. As a hybrid approach of chemical absorption and membrane separation, it may offer a number of important features, including operational flexibility, compact structure, linear scale up and predictable performance. The main challenge is the additional membrane mass transfer resistance, especially when this resistance increases due to the absorbent intruding into the membrane pores. In this thesis, the experimental was set up to investigate how the operating parameters affect the absorption performance when using absorbent in hollow fiber contactor, and to obtain the optimal range of operation parameters for the designated membrane gas absorption system . During 20 days’ continuous experiment, we observed that the CO2 mass transfer rate decreases significantly following the operating time, which is attributed to the increase of membrane mass transfer resistance resulting from partial membrane wetting. To better understand the wetting evolution mechanism, the immersion experiments were carried out to assume that the membrane fibers immersed in the absorbents would undergo similar exposure as those used in the membrane contactor. 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 diffuse into the polypropylene (PP) 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, CO2 loading, as well as 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 PP membrane by surface modification may be an effective way to improve the membrane long-term performance. Modification of the polypropylene membrane by depositing a rough layer of PP was carried out in order to improve the non-wettability of membrane. The comparison of long-term CO2 absorption performance by PP membranes before and after modification proves that the modified polypropylene membranes retained higher hydrophobicity than the untreated polypropylene membrane. Therefore modification is likely to be more suitable for use in membrane gas absorption contactors for CO2 separation, particularly over long operation time.
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Beddoe, Jennifer L. "Determination of single and competitive binary absorption isotherms for R and S optical isomers of fluoxetine /." Electronic version (PDF), 2007. http://dl.uncw.edu/etd/2007-3/beddoej/jenniferbeddoe.pdf.
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Rupp, Jochen. "Acoustic absorption and the unsteady flow associated with circular apertures in a gas turbine environment." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12984.
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This work is concerned with the fluid dynamic processes and the associated loss of acoustic energy produced by circular apertures within noise absorbing perforated walls. Although applicable to a wide range of engineering applications particular emphasis in this work is placed on the use of such features within a gas turbine combustion system. The primary aim for noise absorbers in gas turbine combustion systems is the elimination of thermo-acoustic instabilities, which are characterised by rapidly rising pressure amplitudes which are potentially damaging to the combustion system components. By increasing the amount of acoustic energy being absorbed the occurrence of thermo-acoustic instabilities can be avoided. The fundamental acoustic characteristics relating to linear acoustic absorption are presented. It is shown that changes in orifice geometry, in terms of gas turbine combustion system representative length-to-diameter ratios, result in changes in the measured Rayleigh Conductivity. Furthermore in the linear regime the maximum possible acoustic energy absorption for a given cooling mass flow budget of a conventional combustor wall will be identified. An investigation into current Rayleigh Conductivity and aperture impedance (1D) modelling techniques are assessed and the ranges of validity for these modelling techniques will be identified. Moreover possible improvements to the modelling techniques are discussed. Within a gas turbine system absorption can also occur in the non-linear operating regime. Hence the influence of the orifice geometry upon the optimum non-linear acoustic absorption is also investigated. Furthermore the performance of non-linear acoustic absorption modelling techniques is evaluated against the conducted measurements. As the amplitudes within the combustion system increase the acoustic absorption will transition from the linear to the non-linear regime. This is important for the design of absorbers or cooling geometries for gas turbine combustion systems as the propensity for hot gas ingestion increases. Hence the relevant parameters and phenomena are investigated during the transition process from linear to non-linear acoustic absorption. The unsteady velocity field during linear and non-linear acoustic absorption is captured using particle image velocimetry. A novel analysis technique is developed which enables the identification of the unsteady flow field associated with the acoustic absorption. In this way an investigation into the relevant mechanisms within the unsteady flow fields to describe the acoustic absorption behaviour of the investigated orifice plates is conducted. This methodology will also help in the development and optimisation of future damping systems and provide validation for more sophisticated 3D numerical modelling methods. Finally a set of design tools developed during this work will be discussed which enable a comprehensive preliminary design of non-resonant and resonant acoustic absorbers with multiple perforated liners within a gas turbine combustion system. The tool set is applied to assess the impact of the gas turbine combustion system space envelope, complex swirling flow fields and the propensity to hot gas ingestion in the preliminary design stages.
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Kakpovbia, A. E. "Kinetics of the oxidative absorption of H2̲S from gas streams by Iron chelate solutions." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380598.
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