[pt] Neste trabalho foi desenvolvida uma metodologia analítica visando determinar chumbo em querosene e em óleo lubrificante. A voltametria de redissolução anódica com o eletrodo de filme de bismuto (BiFE) foi empregada com a medição do analito nas amostras realizada em meio microemulsionado. O modo de varredura utilizado foi o de onda quadrada (SWV) sendo o desempenho do BiFE comparado com o desempenho observado com o uso do eletrodo de gota pendente de mercúrio (HMDE), este tradicionalmente utilizado nas análises voltamétricas de metais. Na otimização da composição da microemulsão (ME) para o querosene obtevese melhor resultado, em termos de estabilidade e resposta analítica, com 77% de 1-propanol, 13% de fase aquosa (5% ácido nítrico concentrado e 8% água) e 10% de amostra v/v (valores percentuais em volume). No caso da ME para óleo lubrificante a composição otimizada foi 80% de butanol, 10% de fase aquosa (sendo 5% de ácido nítrico concentrado e 5% de água) e 10% amostra dissolvida em xileno. Em ambos os casos, o ácido nítrico serviu como fonte de eletrólitos e para a conversão de espécies químicas metaloorgânicas de chumbo para a forma inorgânica. Após a otimização dos parâmetros instrumentais, os limites de detecção (3sb/a) foram estimados na ordem de nmol L-1 independentemente do eletrodo empregado. Testes de recuperação em material de referência certificado (NIST 1085a) e em amostras fortificadas com Pb (tanto na forma inorgânica quanto na metaloorgânica) indicaram valores recuperados entre 98 e 100%. Os resultados foram confirmados por análises das mesmas amostras por espectrometria de absorção atômica com atomização eletrotérmica. Foi realizado um estudo para avaliar a magnitude das fontes de incerteza de medição voltamétrica de chumbo e o impacto de cada uma das fontes na incerteza combinada. Verificou-se que a contribuição relacionada com a preparação das soluções (padrões e amostras) foi a mais relevante, indicando a necessidade de se traçar novas estratégias de preparação de soluções e de amostragem para a minimização da incerteza combinada. A partir desse estudo, mostrou-se a viabilidade do uso de meio microemulsionado na determinação eletroanalítica de metais em frações de petróleo mais pesadas. / [en] In the presente work, was developed an analytical method aiming the determination of lead in kerosen and in lubricating oil. Anodic redissolution voltammetry with a bismuth-film electrode was employed by measuring the analyte in the sample microemulsions. Square-wave scanning mode (SWV) was employed and the BiFE performance was compared to the one achieved using the static drop mercury electrode (HDME), the later a more traditional electrode for voltammetric analysis for metals. The optimization of the composition of kerosene microemulsion (ME) indicated best results, in terms of stability and analytical response, with 77% of 1-propanol , 13% of aqueous phase (5% concentrated nitric acid and 8% water) and 10% of sample (percent values in volume). For the lubricating oil, the ME composition was 80% of buthanol , 10% of aqueous phase (5% concentrated nitric acid and 5% water) and 10% of sample previously dissolved in xylene. In both cases, the nitric acid played a role as a source of electrolytes and in converting lead metallo-organic species in the inorganic form. After the optimization of experimental parameters, limits of detection were in the nmol L-1 range no matter the type of electrode employed. Recovery tests in certified reference materials (NIST 1085a) and in lead-fortified samples (either with inorganic and metallo-organic form) indicated recovered values between 98 and 100%. These results were confirmed by analyzing the same samples by electrothermal atomic absorption spectrometry. A study was also made to evaluate the measurement uncertainty sources and magnitudes of the voltammetric determination of lead and the impact of each of the sources in the combined uncertainty. As a result, the contribution of the preparation of solutions (samples and standards) was found to be the most relevant source of uncertainty, indicating the need for establishing alternative strategies for such procedures, aiming the minimization of the combined uncertainty. This work has demonstrated the viability of using microemulsions for eletroanalytical determination of metals in petroleum fractions.

Ensejou-se obter a caracterização do Querosene via espectroscopia de infravermelho próximo com o objetivo de se instalar um analisador NIR (Near InfraRed) na unidade de processo de destilação industrial, permitindo a otimização do processo de produção. Foi construído um banco de dados espectrais (NIR) e das propriedades: densidade D20/4oC, destilação (PIE, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% e PFE), enxofre total, ponto de fulgor, ponto de congelamento e viscosidade a -20oC e a 40oC durante um período de 8 meses. A partir dos dados experimentais foram construídos modelos de inferência para as propriedades do querosene através dos métodos PLS (Partial Least Squares) e redes neurais. Inferências a partir de dados operacionais foram também elaboradas para comparação. As inferências construídas com os dados espectrais apresentaram resultados melhores que as obtidas com as variáveis operacionais. / This work aimed to obtain the characterization of Kerosene by Near Infrared Spectroscopy (NIR) with the intention to install a NIR analyzer at an industrial process of distillation, allowing optimization of the production process. A database of spectral data (NIR) was built and another with the properties: density D20/4oC, distillation (IBP, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and FBP), total sulfur, flash point, freezing point and viscosity at -20oC and 40oC for a period of 8 months. Models of inference to kerosene properties by the PLS (Partial Least Squares) and neural networks methods were built up from experimental data. Inferences from operational data were also compiled for comparison. As a conclusion of this work, inferences from spectroscopy data were better than those from operational data.

Face à l’explosion du trafic aérien attendue ces prochaines années, l’impact de l’aviation civile sur l’environnement est un enjeu majeur. Les instances environnementales internationales comme l’ACARE (Conseil Consultatif pour la Recherche Aéronautique en Europe), en partenariat avec les grands groupes aéronautiques internationaux, ont fixé des objectifs drastiques pour préserver l’environnement : une réduction des émissions de CO2de 75 %et une réduction de 90 % des rejets d’oxydes d’azote dans l’atmosphère sont attendues d’ici 2050 par rapport aux avions fabriqués au début du 21èmesiècle. Les turbomachines actuelles possédant un degré de maturité très élevé ne permettront pas d’atteindre ces objectifs. Les motoristes cherchent donc à étudier de nouveaux concepts en rupture technologique pour les horizons 2050, comme les moteurs à détonation, ou encore les moteurs de type combustion à volume constant. Actuellement, les phénomènes physiques associés à la combustion du kérosène dans ce type de moteur sont encore mal documentés. L’objectif de cette thèse est donc de contribuer à l’amélioration de la connaissance et de la compréhension de ces phénomènes physiques.Au cours de cette étude, les flammes de pré-mélanges de kérosène et d’air sont étudiées expérimentalement grâce à des diagnostics optiques (strioscopie,PIV) et métrologiques. Le processus de combustion est notamment étudié dans des conditions thermodynamiques semblables à celles rencontrées dans un moteur aéronautique. La phase de propagation est dans un premier temps analysée dans des conditions laminaires et adiabatiques à travers la détermination de la vitesse fondamentale de flamme non-étirée, grandeur qui pilote le processus de combustion. Puis la sensibilité du front de flamme à l’étirement et la formation des instabilités de combustion sont dans un second temps examinées. Enfin, la phase d’allumage des pré-mélanges de kérosène et d’air dans des conditions aérodynamiques critiques est elle aussi traitée.Un second point abordé au cours de cette étude concerne la reproduction d’un kérosène réel par un substitut constitué d’un nombre d’espèces limité pour simplifier les problématiques industrielles et les études amont. En effet, la composition d’un kérosène commercial est complexe et variée et l’utilisation d’un représentant permet de modéliser numériquement le phénomène de combustion plus facilement. La pertinence de quelques surrogates plus ou moins représentatifs, formulés dans la littérature et élaborés au cours de différents travaux est notamment traitée dans cette étude en comparant les résultats obtenus avec ceux d’un kérosène commercial. De plus, la modélisation de ces kérosènes de substitution par un schéma cinétique valide estégalement analysée.Ce travail prend place dans le cadre de la chaire industrielle CAPA sur la combustion alternative pour la propulsion aérobie financée par SAFRANTech, MBDA et l’ANR. / With air traffic expected to soar in the next few years, the impact of civil aviation on the environment is a major issue. International environmental organizations such as ACARE (the Advisory Council for Aeronautical Research and Innovation in Europe), in partnership with the main international aeronautical groups, have set drastic objectives to preserve the environment: a reduction of 75 % of CO2emissions and a reduction of 90 % of nitrogen oxide emissions into the atmosphere are sought by 2050, with reference to aircraft produced at the beginning of the 21st century. Current turboshaft engines have a very high degree of maturity and may not achieve these objectives. Engineers are therefore aiming to study new concepts that will become technological breakthroughs at the 2050 horizon, such as detonation engines or constant volume combustion engines. Currently, the physical phenomena associated with the combustion of kerosene in those kinds of engines are still poorly documented. The objective of this PhD thesis is to contribute to the improvement of the knowledge and understanding of these physical phenomena. In this work, premixed flames of kerosene and air are experimentally studied with optical diagnostics (Schlieren, PIV) and metrology techniques. The combustion process is here studied in thermodynamic conditions similar to those encountered in an aeronautical engine. First, the propagation phaseis analyzed in laminar and adiabatic conditions through the determination of the unstretched laminar burning velocity, which drives the combustion process. Then, in a second stage, the sensitivity of the flame front to stretch and the formation of combustion instabilities are examined. Finally, the ignition phase of premixed flames of kerosene and air under critical aerodynamic conditions is also investigated. A second issue tackled in this work is the reproduction of a real kerosene by a surrogate made up of a limited number of species, to simplify industrial problems and initial studies. Indeed, the composition of a commercial kerosene is complex and can vary, and the use of a surrogate allows an easier numerical simulation of the combustion process. The relevance of some more or less representative surrogates, formulated in the literature and elaborated all through different studies, is also studied in this thesis, by comparing the results obtained with those of a commercial kerosene. In addition, the modelling of those surrogates by a valid chemical kinetic mechanism is also analyzed. This research was conducted within the CAPA industrial Chair project dedicated to innovative combustion modes for air-breathing propulsion, financially supported by SAFRAN Tech, MBDA and France’s ANR national research agency.

No description available.

Characterization of jet fuels obtained from sources other than crude oil is a modern area of research that is developing continuously to replace available petroleum-based fuels with ‘drop-in’ alternative fuels. Therefore, reliable composition-property relations are developed to correlate the hydrocarbon compositions of formulated synthetic fuels with their properties to be certified for aviation commercial use. Intensive studies have been initiated at Texas A&M University Qatar in collaboration with industry and academia to study synthetic jet fuels derived from natural gas. These studies are being implemented at its Fuel Characterization Lab where the most advanced testing equipment is used and strict Quality Management and safety systems are followed. This study is divided into two tracks. The first track is focused on conducting experimental investigations using in-house formulated synthetic jet fuels derived from natural gas via Gas-to-Liquid technology and Fischer-Tropsch chemistry. Throughout this research work, these fuels will be referred to as Synthetic Paraffinic Kerosene (SPK). These experimental investigations activities are composed of three phases: the first phase focuses on the influence of SPK building blocks (paraffinic hydrocarbons) on fuels’ properties, the second phase concerns evaluating the role of aromatics and cyclo-paraffins on properties, and the third phase studies the influence of mixing SPK with conventional Jet A-1 derived from crude oil. All of the aforementioned experimental investigations are aimed at building an experimental data bank to assist the efforts of the formulation of new generations of SPKs that meet aviation industry standards. On the other hand, the second track is directed towards the development of mathematical correlations for four properties of high importance to SPK certification. These correlations aim at optimizing fuel composition whereby major physical/chemical properties of ASTM D1655 are met at the lowest cost of composed fuel. The primary findings of this study showed that GTL derived SPK paraffinic constituents can improve certain properties while affecting others negatively, and emphasizing the necessity of aromatics in improving specific properties. Further studies compensating the absence of aromatics and sulfur through blended Jet A-1 revealed a practical solution through jet fuels optimization based on cost and technical effective manners.

South Africa is one of the few developing countries able to design and build satellites; however it is reliant on other nations to launch them. This research addresses one of the main technological barriers currently limiting an indigenous launch capacity, namely the development of a locally designed liquid fuel turbopump. The turbopump is designed to function in an engine system for a commercial launch vehicle (CLV) with the capacity to launch 50-500 kg payloads to 500 km sun synchronous orbits (SSO) from a South African launch site. This work focuses on the hydrodynamic design of the impeller, vaneless diffuser and volute for a kerosene (RP-1) fuel pump. The design is based on performance analyses conducted using 1D meanline and quasi-3D multi-stream tube (MST) calculations, executed using PUMPAL and AxCent software respectively. Specific concerns that are dealt with include the suction performance, cavitation mitigation, efficiency and stability of the pump. The design is intended to be a relatively simple solution, appropriate for a South African CLV application. For this reason the pump utilises a single impeller stage without a separate inducer element, limiting the design speed. The pump is designed to run at 14500 rpm while generating 889 m of head at a flowrate of 103.3 kg/s and consuming 1127.8 kW of power. The impeller has six blades with an outer diameter of 186.7 mm and axial length of 84.6 mm. The impeller's high speed and power requirement make full scale testing in a laboratory impractical. As testing will be a critical component in the University of KwaZulu-Natal's turbopump research program, this work also addresses the scaling down of the impeller for testing. The revised performance and base dimensions of the scaled impeller are determined using the Buckingham-Pi based scaling rules. The test impeller is designed to run at 5000 rpm with a geometric reduction of 20%, using water as the testing medium. This gives an outer diameter of 147.8 mm and an axial length of 69.9 mm. At its design point the test impeller generates a total dynamic headrise of 67.7 m at a flow rate of 18 kg/s, with a power requirement of 15 kW. A method for maintaining a similar operating characteristic to the full scale design is proposed, whereby the scaled impeller's blade angle distribution is modified to maintain a similar diffusion characteristic and blade loading profile. This technique is validated by MST analysis for off-design conditions with respect to both speed and flowrate. / M.Sc.Eng. University of KwaZulu-Natal, Durban 2013.

It is widely accepted that climate change is a very serious environmental concern. Levels of carbon dioxide (CO2) and other emissions in the global atmosphere have increased substantially since the industrial revolution and now increasing faster than ever before. There is a thought that this has already led to dangerous warming in the Earth’s atmosphere and relevant changes around. Emissions legislations are going to be stringent as the years will pass. Hydro carbon fuel cost is also increasing substantially; more over this is non- renewable source of energy. There is an urgent need for novel combustor technologies for reducing emission as well as exploring alternative renewable fuels without effecting combustor performance. Development of novel combustors needs comprehensive understanding of conventional combustors. The design and development of gas turbine combustors is a crucial but uncertain part of an engine development process. At present, the design process relies upon a wealth of experimental data and correlations. Some major engine manufacturers have addressed the above problem by developing computer programs based on tests and empirical data to assist combustor designers, but such programs are proprietary. There is a need of developing design methodologies for combustors which would lead to substantial contribution to knowledge in field of combustors. Developed design methodologies would be useful for researchers for preliminary design assessments of a gas turbine combustor. In this study, step by step design methodologies of dual annular radial and axial combustor, triple annular combustor and reverse flow combustor have been developed. Design methodologies developed could be used to carry out preliminary design along with performance analysis for conventional combustion chambers. In this study the author has also proposed and undertaken preliminary studies of some novel combustor concepts. A novel concept of a dilution zone less combustor has been proposed in this study. According to this concept dilution air would be introduced through nozzle guide vanes to provide an optimum temperature traverse for turbine blades. Preliminary study on novel dilution zone less combustor predicts that the length of this combustor would be shorter compared to conventional case, resulting in reduced weight, fuel burn and vibrations. Reduced fuel burn eventually leads to lower emissions. Another novel concept of combustor with hydrogen synthesis from kerosene reformation has been proposed and a preliminary studies has been undertaken in this work. Addition of hydrogen as an additive in gas turbine combustor shows large benefits to the performance of gas turbine engines in addition to reduction in NOx levels. The novel combustor would have two stages, combustion of ~5% of the hydrocarbon fuel would occur in the first stage at higher equivalence ratios in the presence of a catalyst, which would eventually lead to the formation of hydrogen rich flue gases. In the subsequent stage the hydrogen rich flue gases from the first stage would act as an additive to combustion of the hydrocarbon fuel. It has been preliminary estimated that the mixture of the hydrocarbon fuel and air could subsequently be burned at much lower equivalence ratios than conventional cases, giving better temperature profiles, flame stability limits and lower NOx emissions. The effect of different geometrical parameters on the performance of vortex controlled hybrid diffuser has also been studied. It has been predicted that vortex chamber in vortex controlled hybrid diffuser does not play any role in altering the performance of diffuser. The overall contribution to knowledge of this study is development of combustor preliminary design methodologies with different variants. The other contribution to knowledge is related to novel combustors with a capability to produce low emissions. Study on novel combustor and diffuser has yielded application of two patent applications with several other publications which has resulted in a contribution to knowledge. A list of research articles, two patents, awards and achievements are presented in Appendix C.

In regions with low energy access kerosene lamps are commonly used, and these emit carbon dioxide (CO2) as well as household air pollutants (HAP). This bachelor thesis examines the possible reduction of carbon dioxide equivalents (CO2eq) emissions and HAP from kerosene lamps by replacing them with off-grid solar powered lanterns. Life cycle assessment, or LCA, is used as a method to assess CO2eq emissions from the solar lanterns. Data on emissions from the different stages in the solar lantern lifecycle, as well as for the kerosene lamps, is gathered through literature studies. Furthermore, possible improvements of health and social aspects as result of replacing kerosene lamps are studied and discussed. The results show that CO2eq emissions could be significantly lower if solar lanterns were used. During a lifetime of 30 years, a simple kerosene lamp emits a total of 15 500 kg CO2eq, a hurricane lantern 7 900 kg CO2eq, whereas a solar lantern emits 66.1 kg CO2eq. However, it is found that the possible harmful effects of HAP are much larger than those of CO2. Finally, possibilities and challenges regarding implementation and usage of off-grid solar powered lanterns are identified and discussed.

Orientador: Chang Hung Kiang / Banca: Everton de Oliveira / Banca: Holger Weiss / Banca: Luis Tadeu Furlan / Banca: Miguel Alfaro Soto / Resumo: Vazamentos acidentais de derivados de petróleo podem ocorrer em refinarias, dutos, postos de serviços e no transporte rodoviário ou ferroviário, ocasionando diversos impactos ambientais. Este trabalho teve por objetivo avaliar o comportamento de uma pluma de fase livre de querosene, presente em uma área industrial no município de Paulínia (SP), e estudar a recuperação de querosene em resposta à variação sazonal das chuvas. A área de estudo apresentou seis litotipos de origem fluvial, destacando-se a presença de paleocanais preenchidos por areias grossas. Verificou-se que as grandes variações nos níveis d'água proporcionam o fenômeno de trapeamento/destrapeamento do querosene, afetando diretamente o processo de remediação. A área apresenta altas taxas de recarga, variando de 370 mm a 550 mm em um ano. Após 40 meses de remediação, em que se procedeu ao bombeamento de oito poços, foram recuperados 176.000 litros de querosene. O período de maior recuperação foi de outubro a janeiro. Cálculos efetuados a partir dos índices físicos do solo, das propriedades físicas do querosene e da espessura observada de fase livre, em dezembro de 2008, permitiram estimar um volume remanescente recuperável de 192.000 litros de querosene no subsolo / Abstract: Accidental spills of petroleum products may occur in refineries, pipelines, and service stations, as well as during roadway and railway transportation, causing environmental damages. The main objective of this thesis is to evaluate the behavior of a kerosene free phase plume in an industrial area of the municipality of Paulinia, and evaluate the role of water table fluctuation on hydrocarbon recovery. Six lithofacies deposited in fluvial environment were identified, in particular paleochannels filled by coarse grain sands. An important finding was large water table fluctuation induce entrapment/release of kerosene, greatly affecting aquifer remediation. The studied aquifer underwent high recharge rates of 370 mm to 550 mm per year. Throughout 40 months of remediation, in which eight submersible pumps were employed, 176.000 liters of kerosene were recovered. The largest period of kerosene recovery was in the interval comprising October to January. Calculations using soil physical indexes, physical properties of kerosene and the observed thickness of free phase, as measured in December of 2008, allowed to estimate a volume of 192.000 liters of recoverable remnant kerosene yet in the ground / Doutor

Au cours de ces dernières années les activités de recherches sur les carburants reformulés destinés au secteur aéronautique ont considérablement augmenté. En effet, le fort développement du secteur aérien pousse les scientifiques à chercher une alternative au carburéacteur destiné aux aérodynes dans le but d’économiser le pétrole mais aussi de lutter contre le réchauffement climatique et la pollution atmosphérique. Dans cette thèse nous avons mené des expériences d’oxydation sur trois hydrocarbures lourds, un kérosène conventionnel Jet A-1, des kérosènes reformulés (bio kérosène) et de synthèse (carburant issu de la synthèse Fischer-Tropsch). Ces études ont été réalisées en réacteur auto-agité par jets gazeux à haute pression (10 atm), dans un large domaine de températures (550-1150 K) et à trois richesses (Ф=0,5, 1 et 2). Les analyses par spectrométrie d’absorption infrarouge à transformée de Fourier (IRTF) et la 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. / In recent years research activities on reformulated fuels for the aviation industry have increased. Indeed, the strong development of the airline industry pushes scientists to seek for alternative jet fuel intended for aerodynes in order to preserve oil but also to fight against global warming and air pollution. In this thesis we have conducted experiments on the oxidation of three heavy hydrocarbons, a conventional Jet A-1, reformulated jet fuels (bio-kerosene) and synthetic kerosene (Fischer-Tropsch jet fuel). These studies were carried out in jet stirred reactor at high pressure (10 atm), in a wide temperature range (550-1150 K), for three equivalence ratios (Ф=0.5, 1, and 2). Chemical analyses by Fourier Transformed Infra-Red spectrometry (FTIR) and gas chromatography (GC-FID-TCD-MS) allowed us to measure concentration profiles of reactants, stable intermediates and final products versus temperature. Detailed chemical kinetic reaction mechanisms adapted to the studied compounds were developed and validated by comparison with experimental results.