Quantitative Planar Laser Induced Fluorescence (QPLIF) is developed as a diagnostic technique and then applied to a prototype Jaguar optical internal combustion engine. QPLIF derives quantitative, two-dimensional, spatially-resolved measurements of fuel concentration. This work reports the first demonstration of a fully-fractionated surrogate fuel which exhibits all the characteristics of a typical gasoline. This 'pseudo' fuel, developed in association with Shell UK, is blended to accept a fluorescent tracer which may track one of the light, middle or heavy fractions of the fuel, each of different volatility. The traditional weaknesses of PLIF for quantitative measurements are addressed by use of a fired in-situ calibration method, which maps the quantum efficiency of the tracer and concurrently corrects for window fouling and exhaust gas residuals (EGR). Fuel distributions are presented with an estimated super-pixel accuracy of 10% at different operating conditions, and then compared to the computational fluid dynamics (CFD) predictions of an in-house Jaguar model. Fuel/Air Ratios by Laser Induced thermal Gratings (FARLIG) is developed theoretically, and results of validation experiments conducted in a laboratory setting are reported. FARLIG conceptually enables the measurement of fuel concentration, oxygen concentration and temperature within a spatially-localised probe volume. Uniquely, the technique exploits the dominant influence of molecular oxygen on non-radiative quenching processes in an aromatic tracer molecule. The changing character of a model quenching mechanism potentially allows the oxygen concentration in the measurement volume to be derived. Absolute signal strength is used to determine fuel concentration, while the oscillation period of the signal provides a precise measurement of temperature (~0.3% uncertainty), with accuracy limited by knowledge of the gas composition.

La pyrolyse rapide de biomasse est un procédé de conversion thermochimique qui permet de produire principalement des huiles de pyrolyse valorisables dans le domaine de l’énergie. Les espèces inorganiques initialement présentes dans la biomasse sont à l’origine de problèmes d’instabilité des huiles, de dépôts et d’encrassement. L’objectif de ce travail consiste à mieux comprendre les mécanismes de transfert des inorganiques depuis la biomasse vers les huiles dans les procédés de pyrolyse rapide.Une méthodologie est mise au point afin de quantifier la répartition des alcalins et alcalino-terreux (K, Ca, Mg et Na), identifiés comme les plus néfastes, dans les produits (charbons et huiles) issus de pyrolyse de bois et de paille de blé. Deux dispositifs complémentaires sont utilisés, pour lesquels les bilans de matière bouclent de façon très satisfaisante: un réacteur pilote de pyrolyse rapide en lit fluidisé et un réacteur laboratoire en four tubulaire. Dans tous les cas, le charbon séquestre 99% des éléments minéraux issus de la biomasse. En outre, grâce à un dispositif original de condensation fractionnée des huiles, on démontre que plus de 60% des inorganiques restants dans les huiles de pyrolyse proviennent des aérosols, ce résultat ouvrant une discussion quant à leur origine. Les teneurs en inorganiques des huiles sont par ailleurs fortement liées à la présence de fines particules de charbon mal séparées dans le procédé. Les possibilités de traitement amont ou aval sont discutées, afin de diminuer ces concentrations.Enfin, des expériences parallèles associées à un modèle permettent de décrire quantitativement les mécanismes de transfert entre les particules de charbon et une phase liquide lors du stockage d’huiles de pyrolyse. / Biomass fast pyrolysis is a promising process for the preparation of bio-oils dedicated to energy production. Inorganic species originally present in biomass are known to induce problems such as bio-oil instability, deposits and fouling. The purpose of the present work is to better understand the mechanisms of inorganic species transfer from biomass to bio-oils in fast pyrolysis processes. A methodology is developed for quantifying alkali and alkali-earth species (K, Ca, Mg, Na) distribution in the products (chars and bio-oils) issued from wheat straw and beech wood fast pyrolysis. Two complementary devices are used: a pilot plant fluidized bed reactor, and a horizontal tubular reactor. Mass balances closures are accurately achieved. 99 wt.% of the inorganic species originally contained in biomass are recovered in the chars. Thanks to an original bio-oils fractional condensation device, it is shown that more than 60 wt.% of the inorganic content of overall bio-oil is contained in the aerosols. Different assumptions of possible origins of the aerosols are discussed. Inorganic content of bio-oil is strongly connected to the presence of fine chars particles which are not efficiently separated by the cyclones, and, hence recovered in the bio-oils. The possibilities of upstream or downstream treatments are discussed in order to lower inorganic content of bio-oils. Finally, the mechanisms of inorganics transfers between char particles and a liquid phase, during bio-oil storage, are quantitatively described on the basis of side experiments associated to a model.

Algae have been the centre of recent research as a sustainable feedstock for fuel because of their higher oil yield in comparison to other plant sources. However, algae biofuel still performs poorly from an economic and environmental perspective due to the high reliance on freshwater and nutrients for cultivation, among other challenges. The use of wastewater has been suggested as a sustainable way of overcoming these challenges because wastewater can provide a source of water and nutrients for the algae. Moreover, the ability of the algae to remove contaminants from wastewater also enhances the total economic output from the cultivation. However, the success of this strategy still depends greatly on efficient strain selection, cultivation and harvesting. Therefore, this PhD thesis has focussed on strain isolation, characterisation, optimisation and cultivation in open pond systems. Five algae strains were isolated from wastewater treatment tanks at a municipal water treatment plant in North West England. The isolated strains were morphologically and genetically characterised as green single-celled microalgae: Chlamydomonas debaryana, Hindakia tetrachotoma, Chlorella luteoviridis, Parachlorella hussii and Desmodesmus subspicatus. An initial screening of these strains concluded that C. luteoviridis and P. hussii were outstanding in all comparisons and better than some of the strains previously reported in the literature. Further tests carried out to elucidate the underlying tolerance mechanisms possessed by these strains were based on stress tolerance and acclimation hypotheses. In the following experiments, C. luteoviridis and P. hussii were found to have higher anti-oxidant enzyme activity that helps in scavenging reactive oxygen species produced as a result of exposure to wastewater. This result provides a new argument for screening microalgae strains for wastewater cultivation on the basis of anti-oxidant activity. In addition, the two strains could grow heterotrophically and are better adapted to nutrient deficiency stress than the other three isolates. In order to understand the role of microalgae acclimation in wastewater cultivation, strains identical or equivalent to the wastewater treatment tank isolates were obtained from an algae culture collection. These strains had not been previously exposed to wastewater secondary effluent. The initial growth of these strains in wastewater secondary effluent was very poor. However, after two months of acclimation to increasing concentrations of secondary wastewater effluent, it was observed that growth, biomass and lipid productivities of most of the strains were significantly improved, although still not as high as the indigenous strains. Therefore, it was concluded that continuous acclimation is an additional factor to the successful growth of algae in wastewater. Furthermore, addition of 25% activated sludge centrate liquor to the secondary effluent was found to increase algal growth and biomass productivity significantly. Futher tests to examine the continous cultivation of C. luteoviridis and P. hussii in wastewater showed that a biomas productivity of 1.78 and 1.83 g L-1 d-1 can be achieved on a continual basis. Finally, the capability of C. luteoviridis and P. hussii for full seasonal cultivation in a 150 L open pond in a temperate climate was studied, using the optimised secondary wastewater +25% liquor medium. Each strain was capable of growth all year including in autumn and winter but with strongest growth, productivity and remediation characteristics in the summer and spring. They could maintain monoculture growth with no significant contamination or culture crash, demonstrating the robustness of these strains for wastewater cultivation in a northern European climate.

Anhand einer Fallstudie wird die Arbeit mit dem von der Freiberg Institut für Energie und Klimaökonomie GmbH erschaffenen H2-Tankstellen-Konfigurators dargestellt. Durch die Variation der Wasserstoffversorgung einer fiktiv geplanten H2-Tankstelle wird verdeutlicht, wie die Optimierungssoftware Edgar die Dimensionierung der Anlagentechnik für eine optimale Konfiguration und minimale Kosten verändert. / A case study is used to illustrate the work with the H2 filling station configurator created by the Freiberg Institute for Energy and Climate Economics GmbH. By varying the hydrogen supply of a fictitiously planned H2 filling station, it is illustrated how the optimization software Edgar changes the dimensioning of the plant technology for an optimal configuration and minimal costs.

The development of a clean hydrogen economy will aid a smooth transition from fossil fuels which is required to stem the environmental impact and economic instability caused by oil dependency. For vehicular application, in addition to being cheap and safe, a commercial hydrogen store must contain a certain weight percentage of hydrogen to provide a reasonable range (~300 miles). It must also be able to release hydrogen under near-ambient conditions (80-120°C) and have a reasonable cycling capacity (~1000 cycles). The primary motivation of this thesis is to gain a fundamental understanding into the sorption processes of hydrogen on carbon- and aluminium-based materials to improve their hydrogen storage capacity. The sorption processes of hydrogen on mechanically milled graphite have been investigated, primarily using Electron Spin Resonance Spectroscopy and Inelastic Neutron Scattering. An investigation into the storage properties of tetrahydroaluminates, primarily NaAlH₄ and LiAlH₄, is performed in the presence and absence of a catalyst, and a new phase of NaAlH₄ is observed prior to its decomposition. Variable temperature neutron and synchrotron diffraction, in conjunction with gravimetric and mass spectroscopy data were obtained for several mixtures of tetrahydroaluminates and alkali amides and the hydrogen desorption processes are shown to be quite different from the constituent materials. The structure of Ca(AlH₄)₂ has been experimentally determined for the first time and a complete set of equations describing its decomposition pathway is given.

Parce qu'ils présentent des propriétés remarquables par rapport à leurs équivalents massifs, les nanomatériaux occupent une place de plus en plus importante dans l'industrie et en médecine. Leur essor rapide a généré de nombreuses craintes dans l'opinion publique notamment au regard de certaines méconnaissances liées à leur toxicité. Notre projet vise l'utilisation du séléniure de cadmium (CdSe) comme matériau modèle afin d'établir une corrélation entre la structure chimique des nanoparticules, leur réactivité de surface, leur (photo)stabilité et leur toxicité. Des quantum dots (QDs) CdSe et alliages CdSe(S) ont été préparés en milieu aqueux à 100°C ou par voie hydrothermale de manière à ne différer que par leur structure chimique de coeur (alliage ternaire vs semi-conducteur binaire) alors que d'autres paramètres comme la taille, la charge ou la nature du ligand de surface, ont été maintenus constants. Des études de cytotoxicité menées sur Escherichia coli ont montré que la libération de Cd2+ jouait un rôle important dans la toxicité pour les deux QDs. Nos résultats ont également mis en évidence que les QDs CdSe(S) alliés étaient plus stables et moins toxiques que les QDs CdSe. Sans négliger l'importance de la libération d'ion Cd2+ par les nanoparticules, une corrélation entre la stabilité et la production d'espèces réactives de l?oxygène (EROs) a montré que la toxicité était en partie dépendante de la photostabilité des QDs. Notre étude met en perspective une relation entre la réactivité, la stabilité du coeur des nanoparticules, et la toxicité photo-induite / Due to their unique properties compared to their bulk counterparts, nanomaterials have gained considerable attention, especially in industry and medicine. Their fast development has generated many public concerns, especially because of a lack of knowledge regarding their toxicity. Our project aims to use cadmium selenide (CdSe) as a model material in order to initiate a research aiming at establishing a correlation between the nanoparticles chemical structure, their surface reactivity, their stability and their toxicity. CdSe and alloyed CdSe(S) quantum dots (QDs) were prepared in aqueous phase either at 100°C or under hydrothermal conditions in order to differ solely by their core chemical structure (ternary alloy vs binary semiconductor), while other parameters such as the size, the surface charge or the surface ligand, have been kept constant. Cytotoxicity studies carried out on Escherichia coli have shown that release of Cd2+ played a key role in the toxicity for both QDs. However, alloyed CdSe(S) QDs were also found more stable and less toxic than CdSe nanocrystals. Without disregarding the importance of Cd2+ ions release by the nanoparticles, a correlation between the stability and the production of reactive oxygen species (ROS) showed that toxicity was dependent on QDs photostability. Our study highlights a relationship between the core reactivity, stability and the photo-induced toxicity QD nanoparticles

Microalgae are a diverse group of oxygenic photosynthetic microorganisms which show great promise as a source of biofuel. However, significant challenges still remain before microalgae can be considered a viable source of biofuel. The main current challenges are nutrient sourcing and recycling as well as downstream processing. The algal cell wall and especially the presence of an algaenan cell wall in some Chlorophyte algae could be an important variable in determining downstream processing costs but not much comparative research has been done to elucidate this. The first part of the present study focuses on the recently isolated alga Pseudochoricystis ellipsoidea (Trebouxiophyceae) and its improvement and assessment for biofuel production. Random mutagenesis and FACS screening protocols were developed for the isolation of pigment and cell wall mutants but despite considerable efforts no suitable mutants could be identified in the first half of this project. Two 500 L raceway ponds as well as an algal growth room and bubble column bioreactors were set up to facilitate algal research at the University of Bath and assess the performance of P. ellipsoidea in realistic culture conditions. P. ellipsoidea showed a maximum growth of 1.53 divisions day-1 in semi-open raceway ponds, resistance to contamination and a 30% lipid content, making it particularly suitable for raceway pond cultures. In the second part of this project six species of Chlorophyte (“green”) algae, three of which produced algaenan, were compared for suitability to growth in anaerobic digestate and municipal wastewater as well as cell wall strength, permeability and suitability to hydrothermal liquefaction. We found that anaerobic digestate was a good medium for the growth of all species independently of autoclaving and that non-autoclaved wastewater was a very challenging medium. Algaenan production did not affect cell disruption by ultrasonication but growth stage and cell wall thickness did. Lipid extraction kinetics by chloroform/methanol were greatly affected by algaenan, meaning that this material is relatively impermeable to organic solvents. Cell wall thickness, cell volume and lipid content also had an effect on lipid extraction kinetics but this was only measurable after 180 minutes of extraction. 8 Hydrothermal liquefaction showed high solid and low oil yields, very low sulphur (≤0.1 %) as well as a 1.1 % -1.8 % nitrogen content which is significantly lower than most algal HTL studies to date. This suggests that stationary stage algae are more difficult to process but give a cleaner biocrude and reduce the loss of nitrogen through incorporation in the oil. Significant opportunities for optimisation still exist in the HTL process.

Les carburants liquides actuels sont principalement issus du raffinage du pétrole. Cependant, leur remplacement par des carburants de nouvelle génération, renouvelables, dérivant de la biomasse et plus propre apparait comme une nécessité économique et environnementale. Les buts sont de réduire la dépendance au pétrole dont le prix augmente et les réserves diminuent, et limiter les émissions de dioxyde de carbone (gaz à effet de serre). L'adaptation des motorisations actuelles à ces nouveaux carburants nécessite une connaissance approfondie de leur cinétique de combustion et de la nature et des concentrations des polluants formés lors de leur utilisation. Les activités de recherche sur les carburants alternatifs destinés au secteur aéronautique ont ainsi considérablement augmenté ces dernières années. Dans le cadre de cette étude nous nous sommes intéressés à la solution « carburants de synthèse » qui offrent des perspectives encourageantes pour le futur. Des études cinétiques d’oxydation ont été menées en réacteur auto-agité par jets gazeux (JSR) sur une large gamme de conditions expérimentales à l’Institut de Combustion Aérothermique Réactivité et Environnement sur le campus du CNRS d’Orléans. Ces études ont été menées dans un premier temps sur des hydrocarbures purs qui pourraient être de bons candidats comme molécules-modèles pour représenter la part des iso-paraffines dans un kérosène de synthèse. Ces molécules sont des isomères de l’iso-octane utilisé comme tel jusqu’à maintenant. Dans un second temps, des études ont été menées sur trois kérosènes de synthèse dont un SPK fournit par l’IFP, un CtL (Sasol) et un GtL (Shell). Les analyses par spectrométrie d’absorption infrarouge à transformée de Fourier (IRTF) et par chromatographie en phase gazeuse (CPG-FID-TCD-MS) nous ont permis de mesurer les profils de concentration des réactifs, des produits finals et des intermédiaires stables en fonction de la température. Des mécanismes cinétiques détaillés adaptés aux composés étudiés ont été développés et validés par confrontation avec les résultats expérimentaux. / Current liquid fuels are mainly from petroleum refining. However, replacing them with new-generation alternatives fuels, renewable, from biomass and cleaner appear to be an economic and environmental necessity. Goals are to reduce petroleum dependency whose price increases and supplies decreases, and limit emissions of carbon dioxide (greenhouse gas emissions). The adaptation of existing engines to these new fuels requires a thorough knowledge of their kinetic of combustion and the nature and concentrations of pollutants formed during their use. Research activities on alternative fuels for the aviation industry have considerably increased in recent years. In this study we are interested in the "synthetic fuels" solution that offers encouraging prospects for the future. Studies on the kinetic of oxidation were carried out in a Jet Stirred Reactor (JSR) over a wide range of experimental conditions at the Institute of Combustion Aerothermal Reactivity and Environment on the campus of the CNRS of Orléans. These studies were initially conducted on pure hydrocarbons which could be good candidates as models molecules to represent the isoparaffins cut in a synthetic kerosene. These molecules are isomers of iso-octane used as such until now. In a second step, studies were conducted on three synthetic kerosene, a SPK provided by IFP, a CtL (Sasol) and GTL (Shell). Analyses by Fourier transform infrared spectrometry (FTIR) and by gas chromatography (GC-FID-TCD-MS) allowed us to measure the concentration profiles of reactants, stable intermediates and finals products as a function of temperature. Detailed kinetic mechanisms adapted to the studied compounds have been developed and validated by comparison with experimental results.