Les mélanges GtL/EMHC/éthanol ont un potentiel important comme carburant alternatif pour moteur Diesel.Néanmoins, l’utilisation de ce type de biocarburant en moteur Diesel nécessite une connaissance précise de la cinétiqued’oxydation de ses différents constituants.Une étude bibliographique approfondie a permis de sélectionner quatre espèces modèles représentatives des mélangesGtL/EMHC/éthanol : le n-décane, l’iso-octane, l’octanoate de méthyle et l’éthanol. L’oxydation de mélanges de cesespèces modèles a ensuite été étudiée en réacteur auto-agité à haute pression (10 atm), pour trois richesses (0,5 ; 1 et 2) etsur un large domaine de température (550-1150 K). L’analyse des échantillons par chromatographie en phase gazeuse apermis de quantifier les principaux produits issus de l’oxydation des mélanges étudiés. Un mécanisme cinétique détaillécapable de reproduire l’oxydation des mélanges n-décane/iso-octane/octanoate de méthyle/éthanol a ensuite été mis aupoint. Les prédictions du modèle reproduisent de manière satisfaisante les résultats expérimentaux sur toute la gamme derichesse et de température testée en réacteur auto-agité. L’analyse du modèle a également permis de déterminer les voiesréactionnelles prépondérantes en fonction de la composition des mélanges.Enfin, la combustion de mélanges GtL/EMAG/éthanol a été étudiée en moteur monocylindre Diesel. Cette phased’essais, incluant une analyse approfondie des émissions non réglementées, a permis d’observer l’influence de laformulation des carburants sur l’initiation de la combustion et sur la composition des gaz d’échappements. / As concern about global warming and dependences on fossil fuel grows, there is an increasing interest to shift fromtraditional fuel to renewable energy sources. Blends of Fischer-Tropsch (F-T) fuels, biodiesel and ethanol seem to be apromising fuel for compression ignition (CI) engine application. The aim of this work is to study and model the impact ofthese fuels on combustion and pollutant emissions.In the present study, mixtures of 4 species are proposed to represent the oxidation of F-T/biodiesel/ethanol blends: ndecane,iso-octane, methyl octanoate and ethanol. The kinetic of oxidation of n-decane/iso-octane/methyloctanoate/ethanol blends was studied experimentally in a jet stirred reactor at 10 atm and a constant residence time of 1 s,over the temperature range of 560-1160 K and for three equivalence ratio (0.5, 1 and 2). A kinetic reaction mechanismwas developed and used to simulate the oxidation of n-decane/iso-octane/methyl octanoate/ethanol mixtures. Theproposed kinetic reaction mechanism yields a good representation of the kinetic of oxidation of the tested biofuel blends.The kinetic analyses allowed identifying the most influencing reactions for the oxidation rate of the fuels.Finally, four F-T/biodiesel/ethanol blends have been tested on a single cylinder, direct injection, four-stroke Dieselengine. This study, including an analysis of unregulated emissions allowed observing the influence of fuel formulationon combustion and on pollutant emissions. These main engine results tendencies have been compared to the results of thekinetic model.

Saccharothrix algeriensis est une bactérie filamenteuse capable de produire différentes molécules de la famille des dithiolopyrrolones présentant des activités antibiotiques et anticancéreuses. Ce travail porte sur l’analyse macroscopique et la modélisation du comportement dynamique de cette bactérie en vue de concevoir et d’optimiser un procédé de bioproduction de thiolutine. Les expériences menées en fermenteur de deux litres ont permis de décrire le comportement macroscopique de Sa. algeriensis. Sur substrat mixte (extrait de levure et glucose), la bactérie présente une croissance diauxique. La production de thiolutine, découplée de la croissance, est provoquée par l’épuisement du substrat préférentiel (extrait de levure). L’analyse des bilans carbone, azote et rédox nous a conduit à considérer deux phénomènes physico-chimiques qui n’étaient pas pris en compte dans le modèle proposé par Strub (2008) : l’entrainement de l’ammonium dans la phase gazeuse et l’adsorption des ions ammonium et des acides aminés sur la biomasse. Les données réconciliées sur la base des bilans élémentaires sont utilisées comme support pour la construction d’un modèle stœchio-cinétique. Différentes approches de modélisation des cinétiques et de représentation des bascules métaboliques ont été testées afin de retenir un schéma stœchio-cinétique apparent cohérent avec les données réconciliées. Cette étape de discrimination a été réalisée à l’aide de la toolbox ExOptim, développée en partenariat avec AgroParisTech. Cet outil, alliant une méthode d’optimisation robuste tout en limitant les temps de calcul, permet de prendre en compte les erreurs de mesure dès la mesure initiale et de reparamétrer indépendamment les paramètres du modèle et les données expérimentales. Les cinétiques réactionnelles sont représentées de manière satisfaisante par l’association du modèle de Monod et la loi logistique. Les seize paramètres du modèle sont identifiés sur sept expériences indépendantes. Le modèle finalement obtenu est ensuite testé sur cinq nouvelles expériences aux conditions initiales différentes. Ce modèle permet de prédire raisonnablement les cinétiques de croissance et de production de thiolutine. Toutefois, son utilisation reste limitée à des conditions initiales proches de celles de cette étude. / Saccharothrix algeriensis is a filamentous bacterium that produces several dithiolopyrrolone compounds with antibiotic and antitumor properties. This study focuses on the macroscopic analysis and modelling of the dynamic behaviour of this bacterium, in order to design and optimize the bioproduction process of thiolutin. Experiments were conducted in a two-litres bioreactor to characterise the macroscopic behaviour of Sa. algeriensis. On a medium containing several substrates (yeast extract and glucose), the bacterium shows a diauxic growth. Thiolutin production, which appears to be dissociated from growth, is triggered by the preferential substrate (yeast extract) depletion. The analysis of the carbon, nitrogen and redox balances led us to consider two physicochemical phenomena, which were not taken into consideration in the model proposed by Strub (2008): ammonium stripping in gaseous phase and adsorption of ammonium ions and amino acids on biomass. The data, reconciled on the basis of elementary balances, were used for the construction of a stoichio-kinetic model. Different modelling of kinetic and metabolic switches were tested in order to select a stoichio-kinetic model consistent with the reconciled data. This discrimination step was carried out using the ExOptim toolbox, developed in partnership with AgroParisTech. This toolbox combines a robust optimisation method and a reduced computation time. The experimental biases are taken into account from the first measurement and model parameters and experimental data reconditioned independently. The reaction kinetics are well represented by association of the Monod model and logistic laws. The sixteen model parameters were estimated from seven experiments. Finally, the model was validated by five additional experiments using different initial conditions. The kinetics of growth and thiolutin production are reasonably well predicted. However, the model is limited to initial conditions close to those of this study.

Le méthanethiol est un intermédiaire clé dans la synthèse de la méthionine, un acide aminé largement utilisé dans l'industrie agro-alimentaire. / Methanethiol is a key intermediate in methionine synthesis, an amino-acid which is widely used in food-processing industry.

L'imagerie simultanée IRM-TEP ouvre de nouvelles perspectives pour l'exploration in vivo des fonctions cérébrales. Pour une quantification du signal de tomographie par émission de positons, il est indispensable de corriger l'atténuation tissulaire des photons. En l'absence de mesure tomodensitométrique en IRM-TEP, les cartes de radiodensité ne sont pas disponibles. Il est nécessaire de trouver une méthode fiable et exacte pour générer une carte d'atténuation du sujet à partir des données disponibles TEP ou IRM. Nous avons développé une technique qui génère une carte d'atténuation propre à un sujet par une approche multi-atlas (MaxProb). Cette approche utilise uniquement l'image IRM T1 du sujet, couramment acquise dans les protocoles cliniques et de recherche, ainsi qu'une base de données d'atlas.L'évaluation de MaxProb montre de très bonnes performances, le biais de quantification de l'image TEP étant réduit à moins de 2%. Cette évaluation pratiquée sur une acquisition dynamique TEP a en outre montré qu'une carte d'atténuation imparfaite , combinée à une distribution spatiale inhomogène du traceur au cours du temps, peut produire un biais non-constant des cinétiques TEP. Cela impacte les paramètres biologiques estimés par modélisation sur les cinétiques TEP. La méthode MaxProb n'est cependant pas affectée par ce phénomène. MaxProb fournit une quantification fiable des paramètres physiologiques estimés par modélisation même lorsque le cervelet est utilisé comme région de référence. Notre évaluation a aussi porté sur la reproduction par simulation d'une étude réaliste d'imagerie TEP d'une décharge dynamique d'un neurotransmetteur. Par rapport à la méthode de correction d'atténuation standard (UTE), MaxProb améliore la sensibilité de détection des variations physiologiques, même faibles. Ceci ouvre la voie à de nouveaux protocoles d'imagerie dynamique et simultanée en IRM-TEP, augmentant la puissance de détection, et réduisant les nombres de sujets nécessaires à la mise en évidence d'un phénomène neurophysiologique ou d'un dysfonctionnement physiopathologique / Simultaneous PET-MR imaging brings new perspectives for understanding many aspects of brain function. To achieve PET-MR’s full potential, accurate brain attenuation correction (AC) is required for absolute PET quantification. In PET-MR scanners, radiodensity maps are not directly available unlike in PET/CT, and the attenuation map has to be derived from the MR data (MRAC methods). In this thesis, I have developed a multi-atlas procedure that produces a subject-specific µ-map for brain imaging (MaxProb) via multiple registrations of CT-MR atlas pairs to an MR target. The solution proposed only requires a T1-weighted MRI of the subject, commonly acquired in clinical and research protocols, and a CT-MR atlas database. The MaxProb method permits generating pseudo-CT images for brain MRAC with high accuracy. Results obtained show very good performance of the method and a bias in reconstructed PET of less than 2%. I have also demonstrated for the first time that an inaccurate attenuation correction map, combined with inhomogeneous spatial tracer distribution as is regularly encountered in dynamic brain PET, can lead to a non-constant bias of the activity measure across time, and this can distort kinetic parameter estimation. MaxProb AC is not affected by this phenomenon. Accurate quantification is also achieved with MaxProb on physiological parameters estimated from kinetic modelling, even when cerebellum (surrounded by bone) is used as reference region: In a simulation study, I have shown that compared to a standard approach (UTE), MaxProb multi-atlas MRAC enhances sensitivity to detect physiological variations in binding parameters, opening the way for new dynamic PET studies on simultaneous PET-MR systems

With ever-growing environmental concerns, petrochemical and fine chemical industries face an omnipresent issue in recovering acetic acid from its aqueous solutions. The recovery of acetic acid through the esterification process is a very viable option. However, esterification reactions are typically restricted by equilibrium limitations, and face challenges with product purification. Reactive distillation is an emerging technology that has an extremely attractive potential as a process alternative for carrying out equilibrium limited chemical reactions. Although the reactive distillation process has been successfully commercialised for the manufacture of hIgh commodity chemicals e.g. methyl tertiary butyl ether (MTBE) and methyl acetate, its potential as a separation tool for the recovery of acetic acid using iso-amyl alcohol has not been exploited.

Hydrogen embrittlement is a problem that offers challenges both to technology and to the theory of metallurgy. In the presence of a hydrogen rich environment, applications such as rolling bearings display a significant decrease in alloy strength and accelerated failure due to rolling contact fatigue. In spite of these problems being well recognised, there is little understanding as to which mechanisms are present in hydrogen induced bearing failure. The objective of this thesis are twofold. First, a novel alloy combining the excellent hardness of bearing steels, and resistance to hydrogen embrittlement, is proposed. Second, a new technique to identify the nature of hydrogen embrittlement in bearing steels is suggested. The new alloy was a successful result of computer aided alloy design; thermodynamic and kinetic modelling were employed to design a composition and heat treatment combining (1) fine cementite providing a strong and ductile microstructure, and (2) nano-sized vanadium carbide precipitates acting as hydrogen traps. A novel technique is proposed to visualise the migration of hydrogen to indentation-induced cracks. The observations employing this technique strongly suggest that hydrogen enhanced localised plasticity prevails in bearing steels. While proposing a hydrogen tolerant bearing steel grade, and a new technique to visualize hydrogen damage, this thesis is expected to aid in increasing the reliability of bearings operating in hydrogen rich environments.

L'objectif de ce travail de thèse est le développement d'un modèle numérique prédictif pour la simulation des phénomènes de postoxydation dans la ligne d’échappement d’un moteur à combustion interne. Le modèle a été écrit pour reproduire le processus d'auto inflammation des hydrocarbures durant la postoxydation, mais également l'évolution des polluants et des produits de combustion en général. Ceci a nécessité de mettre au point un schéma cinétique détaillé qui tienne compte de la chimie à basse température des hydrocarbures et de l'influence sur cette chimie des différentes espèces majeures présentes dans les gaz brûlés à postoxyder. Ces espèces sont le CO2, le H2O et le N2, qui agissent comme diluants, mais également des polluants tels que le CO ou les NOx. Ces derniers, même en faibles concentrations, peuvent avoir un effet important sur l’oxydation des hydrocarbures qui doit aussi être prise en compte dans le modèle chimique.Afin de considérer, en plus de la chimie, et les phénomènes physiques de la postoxydation, tels que la turbulence et les effets de mélange, ce schéma cinétique a été couplé à un modèle de combustion turbulente adapté à l'utilisation dans un code CFD 3D moteur. Ce couplage a été effectué via une tabulation a priori de la chimie, méthode qui permet de réduire considérablement le temps de calcul, tout en décrivant l'ensemble des phénomènes liés à la chimie détaillée. Une technique de tabulation de la cinétique chimique a donc été développée et implantée dans un code CFD. Une configuration permettant de représenter les phénomènes caractéristiques de la postoxydation dans la ligne d'échappement d'un moteur à combustion interne a été simulée. Les résultats permettent de mieux appréhender ces phénomènes et de proposer des solutions technologiques visant à leur optimisation / The aim of this PhD thesis is the development of a predictive numerical model capable of simulating hydrocarbon postoxidation in an IC engine exhaust line. The model should reproduce the auto-ignition of hydrocarbons, as well as the evolution of pollutants and combustion products under postoxidation conditions. For this purpose, a detailed kinetic reaction model was developed. It should be valid at low temperatures and under highly diluted conditions. The model should also take into account the effects of the major components of engine exhaust gas on hydrocarbon postoxidation. These are CO2, H2O, and N2, acting as diluting species, but also CO and NOx, which even in small amounts, may strongly impact hydrocarbon oxidation kinetics. These species must hence be considered for postoxidation modelling.In order to gather chemical and physical effects such as turbulence and mixing, the chemical kinetic mechanism was coupled with a turbulent combustion model designed for CFD 3D engine computations. An a priori tabulation methodology was developed, minimizing computational effort and the developed tabulation technique was validated under postoxidation conditions in an IC-engine exhaust line. The coupled chemical kinetics tabulation and turbulent mixing model was implemented in the CFD code IFP-C3D. Simulations were performed on a configuration representative of the physical phenomena characteristic of hydrocarbon postoxidation in exhaust lines. Results improved the understanding of postoxidation phenomena in an IC-engine exhaust line and propose technical solutions for an enhanced postoxidation control

Catalytic hydrotreating (HDT) is a mature process technology practiced in the petroleum refining industries to treat oil fractions for the removal of impurities (such as sulfur, nitrogen, metals, asphaltene). Hydrotreating of whole crude oil is a new technology and is regarded as one of the more difficult tasks that have not been reported widely in the literature. In order to obtain useful models for the HDT process that can be confidently applied to reactor design, operation and control, the accurate estimation of kinetic parameters of the relevant reaction scheme are required. This thesis aims to develop a crude oil hydrotreating process (based on hydrotreating of whole crude oil followed by distillation) with high efficiency, selectivity and minimum energy consumption via pilot plant experiments, mathematical modelling and optimization. To estimate the kinetic parameters and to validate the kinetic models under different operating conditions, a set of experiments were carried out in a continuous flow isothermal trickle bed reactor using crude oil as a feedstock and commercial cobaltmolybdenum on alumina (Co-Mo/γ-Al2O3) as a catalyst. The reactor temperature was varied from 335°C to 400°C, the hydrogen pressure from 4 to10 MPa and the liquid hourly space velocity (LHSV) from 0.5 to 1.5 hr-1, keeping constant hydrogen to oil ratio (H2/Oil) at 250 L/L. The main hydrotreating reactions were hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeasphaltenization (HDAs) and hydrodemetallization (HDM) that includes hydrodevanadization (HDV) and hydrodenickelation (HDNi). An optimization technique is used to evaluate the best kinetic models of a trickle-bed reactor (TBR) process utilized for HDS, HDAs, HDN, HDV and HDNi of crude oil based on pilot plant experiments. The minimization of the sum of the squared errors (SSE) between the experimental and estimated concentrations of sulfur (S), nitrogen (N), asphaltene (Asph), vanadium (V) and nickel (Ni) compounds in the products, is used as an objective function in the optimization problem using two approaches (linear (LN) and non-linear (NLN) regression). The growing demand for high-quality middle distillates is increasing worldwide whereas the demand for low-value oil products, such as heavy oils and residues, is decreasing. Thus, maximizing the production of more liquid distillates of very high quality is of immediate interest to refiners. At the same time, environmental legislation has led to more strict specifications of petroleum derivatives. Crude oil hydrotreatment enhances the productivity of distillate fractions due to chemical reactions. The hydrotreated crude oil was distilled into the following fractions (using distillation pilot plant unit): light naphtha (L.N), heavy naphtha (H.N), heavy kerosene (H.K), light gas oil (L.G.O) and reduced crude residue (R.C.R) in order to compare the yield of these fractions produced by distillation after the HDT process with those produced by conventional methods (i.e. HDT of each fraction separately after the distillation). The yield of middle distillate showed greater yield compared to the middle distillate produced by conventional methods in addition to improve the properties of R.C.R. Kinetic models that enhance oil distillates productivity are also proposed based on the experimental data obtained in a pilot plant at different operation conditions using the discrete kinetic lumping approach. The kinetic models of crude oil hydrotreating are assumed to include five lumps: gases (G), naphtha (N), heavy kerosene (H.K), light gas oil (L.G.O) and reduced crude residue (R.C.R). For all experiments, the sum of the squared errors (SSE) between the experimental product compositions and predicted values of compositions is minimized using optimization technique. The kinetic models developed are then used to describe and analyse the behaviour of an industrial trickle bed reactor (TBR) used for crude oil hydrotreating with the optimal quench system based on experiments in order to evaluate the viability of large-scale processing of crude oil hydrotreating. The optimal distribution of the catalyst bed (in terms of optimal reactor length to diameter) with the best quench position and quench rate are investigated, based upon the total annual cost. The energy consumption is very important for reducing environmental impact and maximizing the profitability of operation. Since high temperatures are employed in hydrotreating (HDT) processes, hot effluents can be used to heat other cold process streams. It is noticed that the energy consumption and recovery issues may be ignored for pilot plant experiments while these energies could not be ignored for large scale operations. Here, the heat integration of the HDT process during hydrotreating of crude oil in trickle bed reactor is addressed in order to recover most of the external energy. Experimental information obtained from a pilot scale, kinetics and reactor modelling tools, and commercial process data, are employed for the heat integration process model. The optimization problem is formulated to optimize some of the design and operating parameters of integrated process, and minimizing the overall annual cost is used as an objective function. The economic analysis of the continuous whole industrial refining process that involves the developed hydrotreating (integrated hydrotreating process) unit with the other complementary units (until the units that used to produce middle distillate fractions) is also presented. In all cases considered in this study, the gPROMS (general PROcess Modelling System) package has been used for modelling, simulation and parameter estimation via optimization process.

This study focuses on the development of novel two-stage esterification-transesterification synthesis of biodiesel from used cooking oil (UCO) using novel heterogeneous catalysts. The esterification of the UCO was investigated using three types of ion exchange resins catalysts including Purolite D5081, Purolite D5082 and Amberlyst 15. Of all the catalysts investigated, Purolite D5081 resin showed the best catalytic performance and was selected for further optimisation studies. From the optimisation study, it was found that the external and internal mass transfer resistance has negligible effect on the esterification reaction. At the optimum reaction conditions, Purolite D5081 achieved 92% conversion of FFA. During reusability study, the conversion of FFA dropped by 10% after each cycle and it was found that progressive pore blockage and sulphur leaching were dominant factors that decreased the catalytic performance of the Purolite D5081 catalyst. A kinetic modelling for FFA esterification was carried out using Purolite D5081 as a catalyst. Three types of kinetic models were investigated i.e. pseudo homogeneous (PH), Eley-Rideal (ER) and Langmuir-Hinshelwood-Hougen-Watson (LHHW). Experimental data obtained from the batch kinetic studies was successfully represented by the PH model and a good agreement between experimental and calculated values was obtained. The activation energy for esterification and hydrolysis reaction was found to be 53 and 107 kJ/moL. The transesterification of pre-treated cooking oil (P-UCO) was investigated using various types of heterogeneous catalysts including Purolite CT-122, Purolite CT-169, Purolite CT-175, Purolite CT-275, Purolite D5081, Diaion PA306s and Cs-supported heteropolyacids catalysts. Of all the catalysts investigated, Diaion PA306s catalyst showed the highest conversion of triglycerides and was selected for further optimisation studies. At the optimum reaction conditions, Diaion PA306s achieved ca. 75% of triglycerides conversion. During the reusability study, Diaion PA306s catalyst gave a similar conversion of triglycerides after being reused once. Therefore, it was concluded that the resin can be used several times without losing catalytic activity. Several purification methods have been investigated and dry washing method was chosen as the best alternative for biodiesel purification.

Surface catalysed reactions play an important role in chemical productions. Developments of catalyst requiring high activity whilst improving on product selectivity can potentially have a profound effect in the chemical industry. Traditional catalyst modifications were focused on tuning the size, shape and foreign metal doping to form well defined metal nanoparticles of unique functionalities. Here, we show new approach to engineering of metal nanocatalysts via a subsurface approach can modify the chemisorption strength of adsorbates on the surface. Carbon modified nanoparticles were synthesised using glucose to stabilise Pd nanoparticles at a molecular level. Upon heat treatment, the carbonised glucose encapsulated the Pd nanoparticles with carbon atoms take residence in the octahedral holes (15 at.%). These materials were tested in liquid phase stereoselective hydrogenations of 3-hexyn-1-ol and 4-octyne. The former has importance in the fragrance industry towards the production of leaf fragrance alcohol. It was shown for the first time that the geometrically and electronically modified Pd with interstitial carbon atoms reduced the adsorption energy of alkenes, ultimately leading to higher reaction selectivity. Boron modified Pd nanoparticles was synthesised using BH₃.THF in the liquid phase. The material possess high B interstitial saturation (20 at.%), which can be synthesised for the first time below 100°C. These materials were tested in the liquid phase selective hydrogenation of various alkynes and 2-chloronitrobenzene, of which the latter has importance in the pesticides industry. Kinetic modelling on the hydrogenation of 4-octyne suggests these subsurface occupied B does play a pivotal role on increasing the reaction selectivity, as removal of these species lead to decreased selectivity. Au nanoparticles were synthesised and characterised using H¹³COOH NMR. The new liquid NMR characterisation method is successfully applied to examine the chemisorption strength of metal nanoparticles. An attempt to synthesise PVP capped B modified Pd nanoparticles with the above NMR characterisation was investigated. It is believed the examples of subsurface atom modifications as shown here may offer future catalyst developments in this area.