CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A reaÃÃo de sÃntese de Fischer-Tropsch tem merecido grande atenÃÃo pela sua aplicaÃÃo no Ãmbito tecnolÃgico e cientÃfico. Este interesse està associado à conversÃo do gÃs natural em produtos lÃquidos de alta qualidade (gasolina e diesel) e elevado valor agregado. No presente trabalho à descrito a metodologia empregada na sÃntese e caracterizaÃÃo de catalisadores bimetÃlicos, com alto teor da fase ativa de ferro e cobalto, usados na sÃntese de Fischer-Tropsch, suportados em sÃlica promovidos com potÃssio e cobre com diferentes proporÃÃes em base molar. O uso de catalisadores de ferro utilizados na sÃntese de Fischer-Tropsch tem sido estudado por muitos pesquisadores, os resultados tÃm mostrado que estes possuem um desempenho satisfatÃrio na produÃÃo de combustÃveis lÃquidos. Entretanto, pesquisas mostram que os catalisadores de cobalto sÃo mais eficientes na produÃÃo de hidrocarbonetos de cadeia longa e linear em relaÃÃo ao ferro. Contudo, catalisadores a base de cobalto sÃo mais caros comparados aos de ferro. Uma relaÃÃo custo/benefÃcio tem que ser atingida na fabricaÃÃo de catalisadores de tal forma que tenhamos uma otimizaÃÃo da produÃÃo de combustÃveis sintÃticos de elevado peso molecular sem muitos gastos com o catalisador. Pretende-se com esta discussÃo, identificar possÃveis vias para o desenvolvimento de catalisadores mais ativos e seletivos, variando a composiÃÃo do promotor estrutural para fins de otimizar a distribuiÃÃo dos produtos (diesel e graxa). A reaÃÃo foi conduzida em um reator de leito de lama. O estudo seguiu um planejamento experimental do tipo fatorial quadrado com ponto central e os resultados foram analisados baseados na metodologia de anÃlises de superfÃcies de respostas. Os efeitos das diferentes condiÃÃes operacionais (temperatura e pressÃo) e dos diferentes teores de potÃssio e cobre na distribuiÃÃo dos produtos lÃquidos foram comparados baseados nos cromatogramas, nÃmero mÃdio de carbono (Nn). Diante dos testes realizados com os catalisadores bimetÃlicos (Fe/Co) dopados com diferentes teores de potÃssio e/ou cobre, chegou-se a uma melhor relaÃÃo entre os metais (K,Cu) para sÃntese de um catalisador mais eficiente (50Fe/50Co/12K/5Cu/139SiO2). Sendo que o objetivo desta formulaÃÃo bimetÃlica, obter vantagens de possÃveis efeitos sinergÃticos entre os dois metais (Fe/Co) e seus promotores estruturais. / The reaction of Fischer-Tropsch synthesis has received great attention for its application in technology and science. This interest is associated with conversion of natural gas into high quality liquid products (gasoline and diesel) and high added value. In the present paper describes the methodology employed in the synthesis and characterization of bimetallic catalysts with high levels of the active phase of iron and cobalt, used in the synthesis of Fischer-Tropsch, supported on silica promoted with potassium and copper with different ratios on a molar basis. The use of iron catalysts used in the Fischer-Tropsch synthesis has been studied by many researchers, the results have shown that these have a satisfactory performance in the production of liquid fuels. However, studies have shown that cobalt catalysts are most effective in producing long-chain hydrocarbons and linear with respect to iron. However, the cobalt-based catalysts are more expensive compared to iron. A cost / benefit ratio has to be reached in the manufacture of catalysts which have such an optimization of production of synthetic fuels of high molecular weight inexpensively with the catalyst. The intention with this discussion, identify possible pathways for the development of more active and selective catalysts, varying the composition of the promoter structure for purposes of optimizing the distribution of products (diesel and grease). The reaction was conducted in a reactor bed of mud. The study followed an experimental planning factorial central square and the results were analyzed based on the methodology of the analysis of response surfaces. The effects of different operating conditions (temperature and pressure) and different concentrations of potassium and copper in the distribution of liquid based on the chromatograms were compared, average carbon number (Nn). Before the tests with the bimetallic catalysts (Fe / Co) doped with different concentrations of potassium and / or copper, it was a better relationship between the metals (K, Cu) for the synthesis of a more efficient catalyst (50Fe/50Co/12K/5Cu/139SiO2). Since the goal of this formulation bimetallic take advantage of possible synergistic effects between the two metals (Fe / Co) and its structural promoters.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A reaÃÃo de sÃntese de Fischer-Tropsch tem merecido grande atenÃÃo pelo seu interesse tecnolÃgico e cientÃfico. Este interesse està associado a conversÃo do gÃs natural em produtos lÃquidos de alta qualidade (gasolina e diesel) e elevado valor agregado. No presente trabalho à descrito a metodologia empregada na sÃntese e caracterizaÃÃo de catalisadores de ferro usados na sÃntese de Fischer-Tropsch, com Ãnfase nos catalisadores suportados em sÃlica e catalisadores industriais (utilizados na sÃntese de amÃnia) promovidos com potÃssio e cobre. Pretende-se com esta discussÃo, identificar possÃveis vias para o desenvolvimento de catalisadores mais ativos e seletivos, variando a composiÃÃo do promotor estrutural para fins de otimizar a distribuiÃÃo dos produtos em fraÃÃes de hidrocarbonetos especÃficos (gasolina, diesel e graxa). A reaÃÃo foi conduzida em um reator de leito de lama. O estudo seguiu um planejamento experimental do tipo fatorial quadrado com ponto central e os resultados foram analisados baseados na metodologia dos grÃficos de superfÃcie de respostas. Os efeitos das diferentes condiÃÃes operacionais (temperatura e pressÃo) e dos diferentes teores de potÃssio na distribuiÃÃo dos produtos lÃquidos foram comparados baseados nos cromatogramas, nÃmero mÃdio de carbono (Nn) e no grau de dispersÃo dos produtos. Para todos os catalisadores de ferro empregados neste trabalho, observou-se um aumento no Ãndice que representa o comprimento da cadeia de hidrocarboneto (Nn) com o aumento do teor de potÃssio. Indicando um maior grau de polimerizaÃÃo para os catalisadores de ferro suportados com 18K em ralaÃÃo aos outros (12K, 6K e industrial). Os resultados mostram que, para catalisadores suportados, em pressÃes elevadas (25 e 30atm) favorecem a produÃÃo de graxa, enquanto a seletividade para hidrocarbonetos lÃquidos à favorecida a baixa pressÃo (20atm) e baixa temperatura (240ÂC). Para os catalisadores industriais, observou-se um aumento na fraÃÃo graxa em baixas temperaturas (240-255ÂC) e elevadas pressÃes (30atm). Contudo, os resultados de todas as corridas para o catalisador suportado e o industrial promovido e nÃo-promovido apresentaram quantidades significativas de n-parafinas com no mÃximo 35 Ãtomos de carbono que pode ser causados atravÃs das limitaÃÃes geomÃtricas e espaciais dentro dos poros do catalisador que tambÃm podem explicar o motivo pelo qual o Ãndice de dispersÃo da distribuiÃÃo de hidrocarbonetos serem mais baixos para um maior nÃmero de carbonos mÃdio. / The Fischer-Tropsch synthesis has been focus of attention of the scientific and industrial community. This interest is related to the conversion of natural gas into high quality liquid products, such as gasoline and diesel, which have high commercial value. In this work the methodology applied to synthesize and characterize iron-based catalyst used in the Fischer-Tropsch synthesis was described. Emphasis was given to catalysts supported in silica and to industrial catalysts (used in the synthesis of ammonia) impregnated with potassium and copper. The catalysts were tested to identify more active and selective catalysts, changing the amount of structural promoter in order to optimize the product distribution of specific hydrocarbons (gasoline, diesel, wax). The reaction was carried out in a slurry phase reactor. The experiments followed a 22 factorial experimental planning with central point and the results were analyzed based on the surface response methodology. The effects of the operating conditions (temperature and pressure) and of the amount of potassium in the catalyst on the liquid product distribution were compared based on the chromatographs, number average number of carbons (Nn) and distribution dispersion. In all iron based catalyst used in the research, the number average number of carbons (Nn) increased with increasing amount of potassium in the catalyst formulation. This result indicates that the catalyst with 18 K supported in silica showed the highest degree of polymerization in comparison with all other catalysts produced in this research. The results showed that for the catalyst supported in silica high pressures (25 to 30 atm) favor the production of wax, while higher selectivity towards liquid fuels was favored by low pressure (20 atm) and low temperature (240ÂC). For the industrial catalyst, an increase in the wax cat was observed at low temperatures (240-255ÂC) and high pressures (30 atm). The experiments carried out with the both catalysts (silica-supported and alumina-supported) have presented significant amounts of n-paraffins with a maximum of 35 carbons and low dispersion of the product distribution which can be caused by space limitations within the catalyst pores.

In the Fischer-Tropsch (FT) synthesis, CO and H2 (synthesis gas) are converted into hydrocarbons that can be further upgraded to high-quality fuels and chemicals. Different carbon sources such as natural gas, coal and biomass can be used as feed-stocks for the synthesis gas. In commercial applications, supported cobalt catalysts are commonly used in the FT synthesis, especially when the synthesis gas emanates from natural gas and when the desired final product is diesel. The activity and selectivity of a cobalt catalyst is dependent on several parameters, one of them being the support. The present thesis is focused on the design, synthesis and characterization of alumina and silica materials (with and without Ce and Zr promoters) with non-conventional morphology, and evaluation of their feasibility as cobalt supports in the FT synthesis. Ce- and Zr-alumina nanoparticles were synthesized by co-precipitation in water-in-oil microemulsion. The obtained product is amorphous alumina with highly dispersed promoters, resulting in strong cobalt-support interactions and low cobalt reducibility. By increasing the calcination temperature of the Ce-promoted support, crystalline CeO2 is obtained which apparently increases the cobalt reducibility and thereby the catalytic activity (per gram catalyst). The small pore size of the materials may induce diffusion limitations on the reactants arrival and/or result in very small cobalt particles, which favour methane over long-chain hydrocarbons.  Successful preparations of pore expanded mesoporous silicas with 1D, 2D and 3D pore structures via the atrane route, combined with the addition of swelling agents, have been demonstrated. The advantage of this method is that pore expansion can be achieved at mild conditions and there is no need for a post-synthesis process using an autoclave system. In larger silica support pores, larger cobalt particles will be formed and the weaker the cobalt-support interactions will be. This generally results in a higher cobalt reducibility for larger-pore supports and thereby a higher catalytic activity. / <p>QC 20171004</p>

Biomass to Liquids via Fischer-Tropsch synthesis (BTL-FT) is regarded as one of the most promising routes for providing alternative solution to growing demand for energy and environmental protection. In Chapter I, the development and key issues of BTL-FT process (especially Fischer-Tropsch synthesis) were reviewed and identified. In Chapter II, Mo/HZSM-5 catalyst was synthesized using Incipient Wetness Impregnation method and tested in nitrogen rich model bio-syngas. Different operation parameters (temperature, pressure, and GHSV) were tested to investigate their influence on the catalytic performance. Those parameters were found to affect the performance significantly. Liquid samples from conversion were mainly composed of C8 to C10 range hydrocarbons. The catalyst characterization revealed that molybdenum species were well distributed on the catalyst support, while dealumination, agglomeration and coke deposition were observed in spent catalyst. The top layer of the spent catalyst had the most coke deposition. A Three-Dimensionally Ordered Macro-porous (3DOM) Fe based Fischer-Tropsch catalyst was developed using a facile in-situ Nitrate Oxidation-PMMA templating technique in Chapter III. Several techniques (including SEM, BET, TPR, HRTEM, XRD, XPS, and DRIFTS) were combined to characterize the morphology, textural properties and microstructures of 3DOM Fe catalysts at different stages. The effects of bio-syngas composition on carbonaceous species formation, iron phase transformation and catalytic performance were investigated and correlated. A novel hybrid bio-refinery process co-converting biomass and natural gas into liquid fuels via FTS with a CO2 recycle loop was developed, modeled and simulated by using Aspen Plus in Chapter IV. The Aspen Plus model utilized experimental data from the 3DOM Fe catalyst. Economic analysis was performed on different scenarios based on the simulation results to determine profitability of the process. Results indicated that 102.65 t/h gasoline and 22.93 t/h diesel can be produced with the co-processing of 100.00 t/h biomass and 112.3 t/h natural gas using 307.78 t/h of recycled CO2 in the process simulation. The carbon conversion rate was estimated to be 81.23% for the hybrid process. Economic analysis revealed that the process can be profitable when using at least 10.00 t/h biomass and 11.23 t/h natural gas.

No description available.

Growing prices, limited supply, and public concern about greenhouse gases associated with crude-derived jet fuels have led to development of renewable alternatives which must be compatible with the worldwide civilian and military aviation infrastructure, which were designed for operation with Jet-A/JP-8. Any alternative fuel should not have negative effects on the aircraft engines and fuel systems, especially from a thermal stability perspective, since any adverse effect of the physical properties, and chemical composition, including existence of trace elements, of those fuels may only be revealed after extensive operation, resulting in higher life-cycle maintenance and operation costs. This study considered four types of alternative fuels: two derived by Fischer-Tropsch (FT) process, and two types of Hydro-processing Esters and Fatty acids (HEFA). For each of these types, both raw and 50:50 blends in volume with Jet-A samples have been prepared, thus resulting in eight different fuel blends. Fit-for-purpose ability of these alternative fuels is first investigated by studying the effects of the fuel properties and composition effects on elastomer materials, and micro-turbine performance. When elastomer o-rings, similar to those used in aircraft fuel systems were immersed in renewable fuels, smaller volume change or swelling was detected (lower than 2%), contrary to a 14% swelling observed for baseline Jet-A. Lower swelling may result into leaks during aircraft operation. This trend was reversed when renewable fuels were blended with aromatics containing Jet-A. Lower energetic content per unit volume of the renewable fuels, resulted in a thrust reduction around 10% when compared to baseline Jet-A at full throttle settings, but other than this, no other significant effect on the engine combustion temperature or other parameters were found for short iv duration testing. On the other hand at the end of the alternative fuel testing an injector issue was detected, which caused a localized heat zone at the turbine stator, and subsequent damage. The investigation of the causes of this nozzle fouling, which may be related to fuel contamination, turbine manufacture defects, or operation conditions is left for future studies. Primary focus of this study is coking behavior of 8 different alternative fuel blends over 4 different metallic surfaces, as compared against baseline Jet-A. A specialized single tube heat exchanger apparatus was used where each fuel sample was allowed to flow through a metal tube placed inside a tube furnace. Thermal stresses caused by the break-down of hydrocarbon molecules and the catalytic effects of the tube surfaces affect thermal stability of the fuel, leading to coking deposits under the auto-oxidation and pyrolysis mechanisms. In the results reported in this study, physical methods such as gravimetric measurements were used to obtain the deposits, while UV/VIS absorption, and GC/MS were used to study chemical changes in fuel composition and their relation with coking deposits. Thermal depositions between 16 and 46 μg/cm2 were measured at the tubes after 3 hours of testing, finding no significant differences between the baseline Jet-A and the renewable fuels blends, even when sulfur levels, which are linked to deposits formation, were lower for the renewable fuels. Fuel bulk constituents, such as paraffins and cycloalkanes, under thermal stressing and catalytic influence of the tube metals cracked into reactive intermediates leading to surface deposits formation, like aromatic compounds. These compounds were identified by the shift towards longer excitation wavelengths of the UV-Vis absorption measurements on stressed fuels.

La presente tesis doctoral emplea herramientas de síntesis y caracterización de catalizadores metálicos nanoparticulados modelo, con el objetivo de elucidar la influencia de varias características estructurales y físico-químicas relevantes y sentar las bases para el diseño de nuevas generaciones de catalizadores avanzados para las rutas catalíticas de conversión de gas de síntesis. Por un lado, el diseño y la síntesis de catalizadores de Co monodispersos, empleando coloides metálicos y soportes nanométricos, en combinación con espectroscopias in situ y operando, ha permitido relacionar la sensibilidad a la estructura no clásica de la síntesis de Fischer-Tropsch (SFT) con modificaciones morfológicas y electrónicas de las nanopartículas de Co durante la catálisis, en función del tamaño de nanopartícula. Por otro lado, este trabajo esclarece la influencia de la historia térmica de los catalizadores de Co, desde los tratamientos más tempranos, en la topología metálica superficial del catalizador activado final y sus consecuencias en la actividad catalítica intrínseca. Adicionalmente, en base al conocimiento adquirido, se ha optimizado la estructura porosa de los catalizadores de Co para la SFT mediante un diseño racional de los soportes catalíticos. De este modo, se ha demostrado que estructuras porosas bimodales macro-mesoporosas así como soportes mesoestructurados con poros uniformes y de longitud reducida dan lugar a catalizadores de actividad mejorada y elevada selectividad a destilados medios. Finalmente, el empleo de soportes sintetizados mediante técnicas de deposición de óxidos capa-por-capa ha permitido sintetizar una serie de catalizadores de Rh promovidos y estudiar su comportamiento en la síntesis selectiva de compuestos oxigenados. Esta tesis presenta, por primera vez, una interpretación general para el papel de los promotores en este sistema. / Prieto González, G. (2010). Requerimientos físico-químicos y estructurales en catalizadores avanzados para la conversión de gas de síntesis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/7026

Thesis (PhD (Process Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: A techno-economic feasibility study was performed to compare biological and thermochemical process routes for production of liquid biofuels from sugarcane bagasse in South Africa using process modelling. Processing of sugarcane bagasse for the production of bioethanol, pyrolysis oil or Fischer-Tropsch liquid fuels were identified as relevant for this case study. For each main process route, various modes or configurations were evaluated, and in total eleven process scenarios were modelled, for which fourteen economic models were developed to include different scales of biomass input. Although detailed process modelling of various biofuels processes has been performed for other (mainly first world) countries, comparative studies have been very limited and mainly focused on mature technology. This is the first techno-economic case study performed for South Africa to compare these process routes using data for sugarcane bagasse. The technical and economic performance of each process route was investigated using the following approach: Obtain reliable data sets from literature for processing of sugarcane bagasse via biological pretreatment, hydrolysis and fermentation, fast and vacuum pyrolysis, and equilibrium gasification to be sufficient for process modelling. Develop process models for eleven process scenarios to compare their energy efficiencies and product yields. In order to reflect currently available technology, conservative assumptions were made where necessary and the measured data collected from literature was used. The modelling was performed to reflect energy-self-sufficient processes by using the thermal energy available as a source of heat and electricity for the process. Develop economic models using cost data available in literature and price data and economic parameters applicable to South Africa. Compare the three process routes using technical and economic results obtained from the process and economic models and identify the most promising scenarios. For bioethanol production, experimental data was collected for three pretreatment methods, namely steam explosion, dilute acid and liquid hot water pretreatment performed at pretreatment solids concentrations of 50wt%, 10wt% and 5wt%, respectively. This was followed by enzymatic hydrolysis and separate co-fermentation. Pyrolysis data for production of bio-oil via fast and vacuum pyrolysis was also collected. For gasification, data was generated via equilibrium modelling based on literature that validated the method against experimental data for sugarcane bagasse gasification. The equilibrium model was used to determine optimum gasification conditions for either gasification efficiency or syngas composition, using sugarcane bagasse, fast pyrolysis slurry or vacuum pyrolysis slurry as feedstock. These results were integrated with a downstream process model for Fischer-Tropsch synthesis to evaluate the effect of upstream optimisation on the process energy efficiency and economics, and the inclusion of a shift reactor was also evaluated. The effect of process heat integration and boilers with steam turbine cycles to produce process heat and electricity, and possibly electricity by-product, was included for each process. This analysis assumed that certain process units could be successfully scaled to commercial scales at the same yields and efficiencies determined by experimental and equilibrium modelling data. The most important process units that need to be proven on an industrial scale are pretreatment, hydrolysis and fermentation for bioethanol production, the fast pyrolysis and vacuum pyrolysis reactors, and the operation of a twostage gasifier with nickel catalyst at near equilibrium conditions. All of these process units have already been proven on a bench scale with sugarcane bagasse as feedstock. The economic models were based on a critical evaluation of equipment cost data available in literature, and a conservative approach was taken to reflect 1st plant technology. Data for the cost and availability of raw materials was obtained from the local industry and all price data and economic parameters (debt ratio, interest and tax rates) were applicable to the current situation in South Africa. A sensitivity analysis was performed to investigate the effects of likely market fluctuations on the process economics. A summary of the technical and economic performances of the most promising scenarios is shown in the table below. The bioethanol process models showed that the liquid hot water and dilute acid pretreatment scenarios are not energy self-sufficient and require additional fossil energy input to supply process energy needs. This is attributed to the excessive process steam requirements for pretreatment and conditioning due to the low pretreatment solid concentrations of 5wt% and 10wt%, respectively. The critical solids concentration during dilute acid pretreatment for an energy selfsufficient process was found to be 35%, although this was a theoretical scenario and the data needs to be verified experimentally. At a pretreatment level of 50% solids, steam explosion achieved the highest process thermal energy efficiency for bioethanol of 55.8%, and a liquid fuel energy efficiency of 40.9%. Both pyrolysis processes are energy self-sufficient, although some of the char produced by fast pyrolysis is used to supplement the higher process energy demand of fast compared to vacuum pyrolysis. The thermal process energy efficiencies of both pyrolysis processes are roughly 70% for the production of crude bio-oil that can be sold as a residual fuel oil. However, the liquid fuel energy efficiency of fast pyrolysis is 66.5%, compared to 57.5% for vacuum pyrolysis, since fast pyrolysis produces more bio-oil and less char than vacuum pyrolysis. / Centre for Renewable and Sustainable Energy Studies

CO2 is a waste product from a number of human activities such as fossil fuel power generation, industrial manufacturing processes, and transport. The rising concentration of CO2 in the atmosphere is heating the planet’s surface via the well-established greenhouse effect; a mechanism for many irreversible climate change impacts. Coupled to this is the ever-increasing global pressure over the availability and access to fossil fuel reserves; the foundations of modern society. In recognition of this CO2 is gaining renewed interest as a carbon feedstock, a changing of attitude viewing it as an asset rather than waste. Carbon capture and utilisation (CCU) technologies are attempting to make use of it. However, little quantitative assessment work has been done to assessand verify such potentials. This thesis applies the principles and framework of the life cycle assessment (LCA) - environmental management tool to early stage CO2 utilisation laboratory processes. All processes employ engineered nanomaterials (ENM) to perform this function, a material class leading the way in the challenges of efficient and feasible CO2 chemistry. The LCA contribution in this thesis acts as a measuring and a guiding tool for technology developers, in the first instance to document the cradle-to-gate impacts of a number of formed ENMs. Appreciating the net environmental benefits of ENM uptake within society has yet to be wholly established, and the unavailability of data is recognised as a major factor. The work of this thesis will thus contribute to knowledge gaps, and be informative to wider community seeking to quantify technical performance benefits of ENMs in the context of net life cycle impact burdens. Finally the actual CCU processes are assessed, initially within the confines of the laboratory but further expanded for consideration at more industrially relevant scales. The potential for sound CCU performance were found achievable under best case conditions, with net GHG impact reductions over the life cycle, and the potential for lower impact carbon products, even carbon negative. However other environmental impacts such as ozone depletion, toxic emissions and the consumption of precious metalores are impacts that require consideration in the use of such technologies.

Les catalyseurs hétérogènes sont des matériaux complexes dont les structures peuvent être modifiées en cours de fonctionnement. Une meilleure compréhension des relations entre propriétés catalytiques et propriétés structurales est nécessaire pour répondre à de nouveaux enjeux environnementaux et économiques. Seules les caractérisations in situ résolues dans le temps i.e. dans des conditions réelles, permettent d'apporter ces informations. Dans ce travail, nous nous sommes intéressés à la caractérisation operando par spectroscopie d'absorption des rayons X (XAS) résolue dans le temps de deux types de catalyseurs hétérogènes : les catalyseurs Fischer-Tropsch et les catalyseurs d'hydrodésulfuration. Si ces catalyseurs sont connus depuis de nombreuses années, peu de caractérisations sont réalisées in situ ou operando au cours de la réaction.Etant données leurs conditions réactionnelles (haute température et haute pression), la mise en œuvre de ces caractérisations a nécessité tout d'abord la construction des outils nécessaires à la caractérisation in situ de catalyseurs hétérogènes sous haute pression de gaz. Ensuite, nous avons réuni un ensemble cohérent de techniques de caractérisation autour du catalyseur Fischer-Tropsch afin de permettre son étude structurale à différentes échelles : l'ordre local avec le Quick-EXAFS et l'ordre à grande distance avec la diffraction des rayons X. Afin d'observer l'effet de la forme cristalline de la phase active sur les propriétés catalytiques, nous avons pour un même catalyseur, activé selon deux voies d'activation, quantifié son activité au moyen de la spectroscopie Raman et la spectrométrie de masse. D'autre part, la caractérisation simultanée de deux centres métalliques, accessible par le dispositif QEXAFS installé sur la ligne de lumière SAMBA, a permis d'obtenir une description fine des processus d'activation des catalyseurs bimétalliques d'hydrodésulfuration. Notre étude s'est portée, sur la comparaison de catalyseurs de même formulation avec des prétraitements différents (séché/calciné) et de deux catalyseurs promus par des métaux différents : le cobalt et le nickel.