Zeolite catalysis plays an important role in many industrial applications due to their unique properties and has become widely used in the area of oil refining. Of particular interest is Zeolite Y, which can be hydrothermally treated into its ultrastable form, USY. USY offers a superior practicality, especially when dealuminated and metal-loaded. The importance of alkanes hydroisomerization arises from the continuingly stricter regulations imposed on the utilization of gasoline as an automotive fuel. The requirements to reduce the aromatics content in gasoline present a need to find an alternative way to maintain its research octane number (RON). An alternative to gasoline's high-octane aromatic content is to increase the RON for the paraffinic content of gasoline, which can be accomplished through hydroisomerization. Commercially, bifunctional metal-loaded zeolites are used to hydroisomerize the light naphtha stream produced at overheads of atmospheric distillation towers. However, no such process exists for the low-value heavy naphtha cut. This targeted process would, if successful, greatly improve refiner's profitability.In this work, bifunctional USY zeolite catalysts are studied in the hydroisomerization of a normal alkane (nC7, RON = 0). This nC7, found in heavy naphtha, has been used as the 'model' compound. The impact of different reaction conditions and catalyst properties on catalyst activity and stability, in addition to the catalyst selectivity to high octane isomers is one step towards determining optimum conditions and preferential catalyst formulations that favour octane maximization. Six platinum-loaded USY zeolite catalysts, four in-house and two commercial, were tested in an atmospheric glass fixed-bed reactor and a stainless steel reactor purpose-built during the course of this thesis. Reaction temperatures ranged from 170 to 250oC at pressures between 1 and 15 bar. The hydrogen to hydrocarbon molar ratio was fixed at 9, with feed space time ranging from 35.14 to 140.6 kg.s/mol. In-house catalysts were hydrothermally treated at different severities, while commercial ones were originally dealuminated through acid-leaching treatments.Results have shown commercial catalyst CBV-712 gave the best performance and highest octane values for product isomers (>30). In addition, there was no coke generation. The next best catalyst was the most severely steamed in-house catalyst (USY-D) that has shown a remarkable performance at high pressures, almost eclipsing the performance of CBV-712, yet produced higher levels of coke. Other USY catalysts tested were less robust during reactions, probably due to imbalance in their acidic to metallic functions, or diffusion limitations arising from their pore structures. The best catalysts were, nonetheless, highly sensitive to sulfur presence in the feed, which severely impacted their activity, especially their metallic functions, and thus require sulfur-free feeds in order to demonstrate their full capacities. Simple kinetic modelling of experimental data was performed using the initial rates method and estimation of kinetic parameters, whose values were in good agreement with previous literature.

Propulsion engine combustor design and analysis require experimentally verified data on the chemical kinetics of limiting fuel combustion rates. Among the important data is the combustion extinction limit as measured by the maximum global strain rate on a laminar, counterflow, non-premixed flame. The extinction limit relates to the ability to maintain combustor operation, and the extinction limit data for pure fuel versus air systems provide a relative reactivity scale for use in the design of flame holders. Extinction limit data were obtained for nine fuels by means of a laminar flame experiment using an opposed jet burner (OJB). The OJB consists of two axi-symmetric tubes (for fuel and oxidizer separately), which produce a flat, disk-like, counterflow diffusion flame. This paper presents results of experiments conducted in an OJB that measured extinction limits at one atmosphere for vaporized n-heptane, the Air Force-developed fuels JP-7, and JP-10, as well as methane, ethane, ethylene, propane, butane, and hydrogen. In hypersonic aircraft development it is desirable to design a Scramjet engine that is operated on hydrocarbon fuel, particularly JP-7 due to its distinct properties. This study provides key data for JP-7, for which very limited information previously existed. The interest in n-heptane is twofold. First, it has undergone a significant amount of previous flame structure and extinction limit study. Second, n-heptane (C7H16) is a pure substance, and therefore does not vary in composition, as does JP-7, which is a variable mixture of several different hydrocarbons. These two facts allow a baseline to be established by comparing the new OJB results to those previously taken. Additionally, the existing data for n-heptane, for mixtures up to 26 mole percent in nitrogen, is extended to 100% n-heptane, reaching an asymptotic limit. Extinction limit data for the two fuels are given with a comparison to hydrogen and several other gaseous hydrocarbon fuels. Complete experimental results are included. / Master of Science

De nombreuses études sont menées pour la compréhension et l'utilisation de plasmas hors équilibre pour les procédés industriels capables d'améliorer la combustion, de stabiliser des flammes et de réduire les polluants. En effet, dans le cadre des nouvelles normes européennes, il devient indispensable de pouvoir maîtriser la qualité de la combustion et de réduire ainsi les émissions polluantes. Même si le principe de l'allumage classique par étincelle est depuis longtemps connu et utilisé dans l’industrie automobile, ce système présente néanmoins quelques limites. En effet, le caractère localisé de l’étincelle créée réduit la probabilité de rencontre entre l’étincelle et une zone de mélange inflammable ce qui conduit à des ratés d’allumages et spécialement en mélanges pauvres. Ainsi, l’utilisation de systèmes différents reposant sur des plasmas non-thermiques fournit des avantages significatifs, dont les propriétés de forte réactivité chimique et de faible coût énergétique. L’objet principal de ce travail de thèse est l’étude de l’allumage de mélanges combustibles par un certain type de décharges pulsées nanosecondes. En effet, un des intérêts du déclenchement de combustion par décharges nanosecondes est le développement d’une zone spatiale d’allumage nettement plus étendue que celle obtenue par l’étincelle de la bougie standard. Enfin, un autre avantage des décharges nanosecondes est la création de nombreux radicaux dans le milieu combustible nécessaires à l’initiation directe des cinétiques de combustion en limitant la contribution thermique, souvent impliquées dans les pertes de rendement des allumeurs. Dans notre étude, la décharge nanoseconde pulsée utilisée est caractérisée par l’application d’une surtension très élevée donnant un pulse de tension très court (12 ns), d’amplitude très élevée (50 kV) et un front de montée très raide (2 ns). Au cours de cette étude, nous avons d’abord caractérisé la décharge nanoseconde pulsée dans des mélanges air/propane et air/heptane à pression atmosphérique. Ensuite, nous avons appliqué la décharge au déclenchement de combustion dans les mélanges air/propane et air/heptane dans les proportions stœchiométriques mais aussi en mélanges pauvres et ce toujours à pression atmosphérique, ce qui a montré la réduction des délais de combustion. De plus, les résultats en mélanges stœchiométriques montrent qu’il existe trois modes d’allumage : un ponctuel, un double et un mode cylindrique et ce en fonction de la densité d’énergie. / One growing topic of interest in the field of non-thermal plasmas is the use of pulsed corona discharges for ignition purposes and more specifically the use of discharges generated under very strong overvoltages for car atmospheric engine applications. Because of strong environmental constraints on car exhaust gases, engines to be developed in the future have to run with lean air / gasoline mixtures or diluted with burnt gases. In both cases, it needs the optimization of ignition devices since classical spark gaps become inefficient in these conditions. In this context, the generation of non-equilibrium plasmas on large volumes, with high densities of active species, and the ability to induce fast gas heating is challenging. Our experimental work is dedicated to the understanding of physical mechanisms involved in the ignition of lean mixtures of air and hydrocarbons such as propane and n-heptane, at high pressure, using nanosecond range discharges. Such kind of discharges could improve the energy release in the mixtures, promoting the creation of radicals and excited species instead of direct heat through Joule effect, and thus, it could improve the ignition efficiency. A positive high voltage (50 kV) is applied between a pin electrode and a grounded plane over a short nanosecond range pulse (12 ns) with a steep rise time (2 ns). In this study, the discharge has been characterised in air/propane and air-heptane mixtures. The diffuse regime observed in pure air tends to disappear in mixtures containing few percents of propane or heptane. The experimental results show the ability of the single nanosecond pulsed discharge to ignite air-propane and air-heptane mixtures even at low equivalence ratios. It is strongly correlated to the energy density the discharge is able to release into the gas. Finally, it has been shown that for stoechiometric mixtures show that three different modes of ignition are possible, i.e. a single point, a double point or a cylindrical mode, according to the energy density. Combustion delays are strongly reduced and complete combustion of very lean mixtures can be achieved if the amount of energy is slightly increased.

Durant les régimes de fonctionnement transitoires à froid des technologies d’Injection Directe Essence, des films liquides peuvent se former sur les parois du cylindre moteur. L’interaction entre le gradient de fraction de vapeur, résultant de l’évaporation de ces films avec le front de flamme, est responsable de la majorité des émissions d’hydrocarbures imbrulés (HC). Dans ces travaux, une configuration expérimentale simplifiée a été développée de façon à générer un gradient de fraction de vapeur par évaporation, dans un contexte d’écoulement réactif confiné, mais préservé des complexités inhérentes aux configurations industrielles. L’étude porte sur les influences de la vitesse de l’écoulement et de la température de l’interface de changement de phase sur les intensités des transferts de masse et de chaleur ainsi que sur l’établissement de la stratification de vapeur. Dans un premier temps, les flux de vapeur et de chaleur provenant d’une paroi poreuse saturée en liquide volatil ont été mesurés et évalués. Dans un second temps, le gradient de fraction de vapeur à proximité de la paroi poreuse a été caractérisé par un diagnostic de Fluorescence Induite par Laser (FIL). L’approche globale a confirmé que le flux de chaleur consommé par le changement de phase représente une part importante du flux de chaleur total échangé. De plus, les résultats de mesures de FIL ont montré l’existence de différents types de distributions et comportements provenant du lien étroit entre la forte densité du mélange gazeux et la formation de la couche de vapeur. / During cold start and warm up engine regimes for Gasoline Direct Injection (GDI) technology, fuel liquid films may accumulate on the cylinder walls. The interaction between the mass fraction gradient, witch is resulting from its evaporation, and the front flame, manages to produce the majority of Unburnt HydroCarbon (UHC) emissions. In order to reproduce the conditions found in internal combustion without the industrial setup complexity, an academic experimental configuration has been developed to generate a mass fraction gradient by evaporation. This study focuses on the influence of the air stream velocity and the influence of the phase change interface temperature. First, mass and heat fluxes from the phase change surface have been measured and calculated near a porous wall saturated with volatile liquid. Then, the mass fraction gradient near the porous wall has been characterised by a Laser Induced Fluorescence (LIF) diagnostic. The global approach has confirmed that latent heat flux represents a major part of the total heat transfer flux exchange. Moreover, LIF results have shown different global behaviours that link the high density of the gas mixture to the vapour layer formation.

De nombreuses études sont menées pour la compréhension et l'utilisation de plasmas hors équilibre pour les procédés industriels capables d'améliorer la combustion, de stabiliser des flammes et de réduire les polluants. En effet, dans le cadre des nouvelles normes européennes, il devient indispensable de pouvoir maîtriser la qualité de la combustion et de réduire ainsi les émissions polluantes. Même si le principe de l'allumage classique par étincelle est depuis longtemps connu et utilisé dans l'industrie automobile, ce système présente néanmoins quelques limites. En effet, le caractère localisé de l'étincelle créée réduit la probabilité de rencontre entre l'étincelle et une zone de mélange inflammable ce qui conduit à des ratés d'allumages et spécialement en mélanges pauvres. Ainsi, l'utilisation de systèmes différents reposant sur des plasmas non-thermiques fournit des avantages significatifs, dont les propriétés de forte réactivité chimique et de faible coût énergétique. L'objet principal de ce travail de thèse est l'étude de l'allumage de mélanges combustibles par un certain type de décharges pulsées nanosecondes. En effet, un des intérêts du déclenchement de combustion par décharges nanosecondes est le développement d'une zone spatiale d'allumage nettement plus étendue que celle obtenue par l'étincelle de la bougie standard. Enfin, un autre avantage des décharges nanosecondes est la création de nombreux radicaux dans le milieu combustible nécessaires à l'initiation directe des cinétiques de combustion en limitant la contribution thermique, souvent impliquées dans les pertes de rendement des allumeurs. Dans notre étude, la décharge nanoseconde pulsée utilisée est caractérisée par l'application d'une surtension très élevée donnant un pulse de tension très court (12 ns), d'amplitude très élevée (50 kV) et un front de montée très raide (2 ns). Au cours de cette étude, nous avons d'abord caractérisé la décharge nanoseconde pulsée dans des mélanges air/propane et air/heptane à pression atmosphérique. Ensuite, nous avons appliqué la décharge au déclenchement de combustion dans les mélanges air/propane et air/heptane dans les proportions stœchiométriques mais aussi en mélanges pauvres et ce toujours à pression atmosphérique, ce qui a montré la réduction des délais de combustion. De plus, les résultats en mélanges stœchiométriques montrent qu'il existe trois modes d'allumage : un ponctuel, un double et un mode cylindrique et ce en fonction de la densité d'énergie.

Iso-octane, n-heptane, ethanol and their blends were tested in a constant volume combustion chamber to measure laminar burning velocities. The experimental apparatus was modified from the previous version to an automatically-controlled system. Accuracy and speed of data acquisition were improved by this modification. The laminar burning velocity analysis code was also improved for minimized error and fast calculation. A large database of laminar burning velocities at elevated temperatures and pressures was established using this improved experimental apparatus and analysis code. From this large database of laminar burning velocities, laminar flame speeds were extracted. Laminar flame speeds of iso-octane, n-heptane and blends were investigated and analysed to derive new correlations to predict laminar flame speeds of any blending ratio. Ethanol and ethanol blends with iso-octane and/or n-heptane were also examined to see the role of ethanol in the blends. Generally, the results for iso-octane and n-heptane agree with published data. Additionally, blends of iso-octane and n-heptane exhibited flame speeds that followed linear blending relationships. A new flame speed model was successfully applied to these fuels. Ethanol and ethanol blends with iso-octane and/or n-heptane exhibited a strongly non-linear blending relationship and the new flame speed model was not applied to these fuels. It was shown that the addition of ethanol into iso-octane and/or n-heptane accelerated the flame speeds. / text

Pollutant control and efficiency improvement propel the need for clean combustion research on internal combustion engines. To design cleaner fuels for advanced combustion engines, gasoline combustion chemistry must be both understood and developed. A comprehensive examination of gasoline combustion chemistry in a jet stirred reactor is introduced in this dissertation. Real gasoline fuels have thousands of hydrocarbon components, which complicate numerical simulation. To mimic the behavior of real gasoline fuels, surrogates, composed of a few hydrocarbon components, are offered as a viable approach. In this dissertation, combustion chemistry of n-heptane, a key surrogate component, is investigated first, followed by an evaluation of a surrogate kinetic model. Finally, real gasoline fuels are assessed with the surrogate kinetic model. Mass spectrometry was employed to measure intermediates in n-heptane low temperature chemistry. Reaction pathways of the observed intermediates were proposed and clarified. n-Heptane low temperature oxidation reaction scheme was expanded by the proposed reactions. After surrogate proposal and formation, a surrogate kinetic model was examined. Low temperature and high temperature chemistry were observed and predicted. The octane number and composition effect on low temperature oxidation reactivity were revealed. High temperature combustion chemistry was found to be similar among the different surrogates, and the surrogate kinetic model reproduced surrogate behavior well in both low and high temperatures. Finally, the proposed surrogate model was examined using real gasoline fuels. Five real FACE (fuel for advanced combustion engines) gasolines were selected as target fuels to cover a wide range of octane number, sensitivity and hydrocarbon compositions. Low temperature oxidation chemistry was investigated for two intermediate octane number gasolines, FACE A and C. For a high octane number gasoline, FACE F, key pollutant production pathways were the focus of high temperature combustion chemistry. Two low octane number gasolines, FACE I and J, were compared with three other FACE gasolines to clarify gasoline combustion chemistry over a wide range. The gasoline surrogate chemical kinetic model proved to be a comprehensive, viable, accurate and powerful approach for numerical simulations. The proposed gasoline surrogate chemical kinetic model can aid in the numerical design of advanced combustion engines.

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In dieser Arbeit werden verschiedene MOF Materialien die sich für die Wasseradsorption eignen hinsichtlich Ihrer Wasseradsorptionseigenschaften untersucht. Das vielversprechendste Material wird ausgewählt und an einem Prüfstand für Lufttrocknerkartuschen untersucht. Für diese Messungen ist eine geeignete Formgebung des Pulvers von Nöten, welche eine wichtige Rolle in dieser Arbeit spielt. Das Material Cu3(BTC)2 wurde hier zu monolithischen Formkörpern verarbeitet. Eine weitere Art der Formgebung war das Pressen von Papieren sowie das direkte Kristallwachstum auf Zellulose Fasern. Desweiteren wurden die Materialien hinsichtlich der Trocknung von n-Heptan untersucht, was hier als Referenz für Dieselkraftstoffe herangezogen wurde. Die Analytik wurde mittels Karl-Fischer Titration duchgeführt. MOF Materialien wurden in beiden Fällen mit kommerziell verwendeten Zeolithen und Silikagel verglichen. / Metal-organic frameworks (MOFs) were investigated for their possible use in drying of compressed air in air braking systems for commercial vehicles. Another possible application was the drying of diesel fuel. In this context, n-heptane was chosen as a reference for diesel fuel. Selected metal-organic frameworks were characterized regarding the water adsorption properties by recording water adsorption isotherms. The most promising material was further investigated on a air-drying cartridge test rig. In order to perform these tests, the powder had to be processed to monolithic structures, beads or paper sheets,i.e. a shape that is suitable for the given application. The MOF Cu3(BTC)2 was sucessfully extruded to monolithic structures, which were used in the test rig experiments. Another possibility for immobilization of Cu3(BTC)2 was the crystal growth on pulp fibers. N-heptane drying isotherms were measured on selected samples making use of Karl-Fischer coulometric titration. In both applications, MOF materials were compared with silica based desiccants.