In this study commercial ultrastable Y zeolite was modified by different synthesis methods as precipitation, impregnation, and thermal hydrolysis, with different titanium and zirconium precursors. The intention was to investigate the effect of these metals in the framework on the zeolite acidity properties and how this influences the performance of the final catalyst on oil processes such as hydrocracking. For precipitation modification, different samples were synthesized varying the time precipitating ranging from one injection up to 9 hours. Samples in impregnation modification were synthesized along with thermal hydrolysis to compare different modification synthesis methods. Zeolite has a strong dealumination effect below pH 2 but low pH is needed to maintain titanium precursor in solution. Thermal hydrolysis shows an improvement in activity compared to precipitation and impregnation better selectivity compared to thermal hydrolysis. Metals preserve aluminum content when exposed to acidic post-treatment and shows improvements in yield of isomers compared to blanks. NH3-TPD showed decrease of weak and strong acid sites with increase of medium acid sites when exposed to acid post-treatment. BAS controls the yield of isomers.

Hydrocracking is one of the most essential catalytic processes in the oil industry for the conversion of heavy fractions of petroleum (light and heavy vacuum gas oil, demetallized oil) and renewable hydrocarbon feedstocks to high-quality fuels. Hydrocracking relies on a bifunctional catalytic process that combines catalytic cracking and hydrogenation steps. In principle, hydrocracking is aimed to convert heavy and ultraheavy oils with maximum fuel selectivity and minimum formation of light gases and polyaromatic compounds, from this high activity and selectivity of the catalyst, is achieved by finding a good balance between its acidic and hydrogenation properties. For this study, platinum catalyst impregnated on alumina was applied for hydrogenation reaction, whereas cracking function was accomplished by ultrastable Y (USY) zeolite. The central objective of the thesis was to study the fundamental effect of extra framework aluminum (EFAl) species forming with the hydrothermal treatment of USY on hydrocracking of selected model compound – n-hexadecane. Three commercial USY zeolites with different SiO2/Al2O3 ratios were steamed until they reached down to the conversion curve of the reference USY sample physically mixed with 1% Pt supported on alumina in a 1:10 ratio. XRD patterns showed that the crystalline faujasite structure was kept after steaming. In the physisorption of argon, slight changes were observed in surface area and pore volumes which were correlated to the structural collapse of the zeolite framework. Dealumination of the zeolite framework was verified by 27Al MAS NMR. FTIR spectroscopy of pyridine adsorption and TPD of ammonia were employed to investigate the acidity of the samples. From the results, it was found that the concentration of Brønsted acid sites was the main contributor to the activity-acidity relationship in n-hexadecane hydrocracking. To gain more insight into the relationship, samples were subjected to n-hexane cracking. Turnover frequency analysis supported the proposal about hydrocracking reaction and also revealed the chemical influence of EFAl on Brønsted acidity observed in catalytic cracking of hexane.

La consommation continue de matières plastiques a conduit, jusqu’à 2015, à l'accumulation de 6,3 milliards de tonnes de déchets plastiques. En Europe, le recyclage des plastiques ramassés ne dépasse pas les 30% pour des raisons logistiques et économiques liées à cette filière. La valorisation énergétique de ces déchets, non valables pour le recyclage, est alors préférée aux autres modes de gestion. L’incinération étant controversée pour son bilan énergétique et environnemental, d’autres moyens de valorisation tels que la pyrolyse sont privilégiés. Les travaux de recherche menés dans cette thèse ont été focalisés sur la pyrolyse des polyoléfines, le polyéthylène (PE) et le polypropylène (PP), en raison de leur forte présence dans les déchets plastiques municipaux. L’influence de la zéolithe Ultrastable Y (USY) sur la pyrolyse du PP et du PE, récupérés d’une déchèterie, a été étudiée par une analyse thermogravimétrique (ATG) puis sur un réacteur en batch à lit fixe et un réacteur continu. L’étude cinétique dedécomposition thermique des mélanges de PP et de PE a été réalisée, les paramètres cinétiques ont été déterminés et les interactions entre les différents composants du mélange ont été analysées. La quantité de zéolithe a été optimisée et le rapport catalyseur/plastique de 1:10 a été adopté durant les essais expérimentaux. L’utilisation de l’USY comme catalyseur a conduit à une distribution plus ciblée de composés et des temps de réaction plus courts. Les liquides de pyrolyse obtenus ont été séparés en différentes fractions de carburants compatibles avec les normes Européennes EN 590 et EN 228. Afin de réduire le coût de production de ces carburants, une étude de régénération du catalyseur a été menée et a montré que son niveau d’activité a diminué au bout de 14 cycles de régénération. A la fin de la thèse, un bilan d’énergie et de masse du procédé a été effectué puis les perspectives d’amélioration sont présentées afin de transposer l’étude à l’échelle industrielle. / Continuous consumption of plastics led, until 2015, to the accumulation of 6.3 billion tons of plastic waste. In Europe, the recycling of collected plastics does not exceed 30% for logistical and economic reasons related to this sector. The energy recoveryof this waste, which is not valid for recycling, is then preferred to other management methods. Incineration is controversial for its energy and environmental balance; other means of recovery such as pyrolysis are preferred. The research carried out in this thesis focused on the pyrolysis of polyolefins, polyethylene (PE) and polypropylene (PP), because of their strong presence in municipal plastic waste. The influence of the ultrastable Y zeolite (USY) on the pyrolysis of PP and PE, recovered from a waste collection center, was studied by thermogravimetric analysis (TGA) and then on a fixed bed batch reactor and a continuous reactor. The kinetic study of thermal decomposition of the PP and PE mixtures was carried out, the kinetic parameters were determined and the interactions between the various components of the mixture were analyzed. The amount of zeolite was optimized and the catalyst/plastic ratio of 1:10 was adopted during the experimental tests. The use of USY as a catalyst has led to a more targeted distribution of compounds and shorter reaction times. The pyrolysis liquids obtained were separated into different fuel fractions compatible with the European standards EN 590 and EN 228. In order to reduce the production cost of these fuels, a catalystregeneration study was conducted and showed that its activity level decreased after 14 cycles of regeneration. At the end of the thesis, an energy and mass balance of the process was carried out and the prospects for improvement are presented in order to transpose the study on an industrial scale.

L’emploi de cristaux de zéolithe USY comme fonction acide et de phases sulfures de type NiMoS comme fonction hydro/deshydrogénante (H/DH) dispersée sur un liant de type alumine [NiMoS/(_-Al2O3 + USY)] permet l'obtention de catalyseurs bifonctionnels d’hydrocraquage très actifs mais dont la sélectivité en distillats moyens est relativement faible. Une des causes invoquées pour expliquer ces performances est la distance importante entre les sites H/DH et les sites acides qui entraine des réactions secondaires et la formation de produits légers. Dans ce travail, une phase H/DH additionnelle (nickel) a été insérée dans des zéolithes USY par différentes méthodes afin d’obtenir des catalyseurs contenant une phase sulfure localisée au plus proche des sites acides. L’utilisation de zéolithes imprégnées à sec et échangées avec du nickel dans des catalyseurs typiques d’hydrocraquage permet d’obtenir de meilleures activités et sélectivités en distillats moyens en hydroconversion du squalane (2,6,10,15,19,23- hexamethyltetracosane) que l’utilisation de zéolithe ne contenant pas de Ni. L’étude de la relation structure-réactivité des catalyseurs a permis de mettre en évidence que l’amélioration de la proximité entre fonction acide et fonction H/DH est bien à l’origine de l’amélioration des propriétés catalytiques. De plus, l’utilisation d’une zéolithe dans laquelle le nickel a été inséré à la synthèse conduit aussi à des résultats prometteurs. Ce travail ouvre ainsi une voie d’amélioration pour des catalyseurs d'hydrocraquage plus actifs et plus sélectifs en distillats moyens par insertion d’une phase H/DH additionnelle / Hydrocracking bifunctional catalysts can be obtained using USY zeolite crystals as an acid function and NiMoS metal sulfide phase as a hydro/dehydrogenating (H/DH) function dispersed on an alumina binder [NiMoS/(_-Al2O3 + USY)]. These catalysts are very active but have a moderate selectivity towards middle distillates. One of the suggested explanations is the large distance between the two different types of catalytic sites leading to secondary reactions and to the formation of light products. In this work, an additional H/DH phase (nickel) has been inserted in USY zeolites using various methods in order to obtain catalysts in which a sulfided phase is located in the vicinity of the acid sites. The use of impregnated or ion exchanged nickel containing zeolites in a typical hydrocracking catalyst leads to higher activities and middle distillates selectivities in the squalane (2,6,10,15,19,23-hexamethyltetracosane) hydroconversion reaction than the use of bare zeolites. According to the structure-reactivity relation of the catalysts, these enhancements are ascribed to an increased proximity between the H/DH function and the acid sites. Moreover, the use of a synthesized Ni-zeolite leads to promising results. The use of an additional H/DH phase as an optimization route for the production of more active and selective hydrocracking catalysts is then clearly supported by this work