• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 102
  • 33
  • 14
  • 11
  • 9
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 245
  • 245
  • 23
  • 23
  • 21
  • 19
  • 19
  • 18
  • 18
  • 17
  • 17
  • 16
  • 14
  • 14
  • 13
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Crude oil/water interface characterization and its relation to water-in-oil emulsion stability. / Contribution à la caractérisation des interfaces eau/brut et leurs effets sur la stabilité des émulsions eau-dans-huile.

Ligiero, Leticia 23 February 2017 (has links)
La formation d’émulsions stables eau/huile lors des processus de récupération et de raffinage du pétrole peut impacter défavorablement l’efficacité de ces opérations. Bien que résines et asphaltènes soient généralement tenus pour responsables de la stabilité des émulsions, la composition exacte des molécules présentes à l’interface eau/huile est en réalité assez mal connue. L’identification de ces molécules et la connaissance de leur influence sur la propriété des interfaces est une étape nécessaire pour mieux prédire les problèmes de stabilité des émulsions dans l’industrie pétrolière. Cette thèse présente des résultats de caractérisation analytique par GPC-ICP-HRMS et FTMS du matériel interfacial (IM) extrait de quatre bruts différents et des espèces transférées dans la phase aqueuse lorsque ces bruts contactent l’eau, ainsi que des propriétés rhéologiques en cisaillement et en dilatation des interfaces eau/huile en présence de ces composés. Les bruts ont été choisis en raison de leur capacité à former des émulsions eau-dans-huile de stabilités différentes. Les mesures d’élasticité de cisaillement ont montré que la majorité des interfaces eau/huile étudiées formaient une structure élastique susceptible de fausser la mesure du module dilatationnel de Gibbs par la méthode d’analyse du profil de goutte. Néanmoins, nous montrons à l’aide de simulations numériques que le module apparent Eapp mesuré dans un tel cas est proche de la somme du module de Gibbs et du module de cisaillement (G) multiplié par 2 du réseau interfacial dès lors que G reste petit (G < 10 mN/m), ce qui est très souvent le cas puisque nous observons que le réseau interfacial formé se rompt lors des expériences de dilatation. Une équation phénoménologique a été développée permettant d’attribuer un temps de relaxation unique aux processus de relaxation qui ont lieu aux interfaces eau/huile, ce qui nous permet de classer les différents systèmes entre eux. Nous avons également étudié les IM extraits des bruts selon la technique chromatographique dite « wet silica method » récemment développée par Jarvis et al. (Energy Fuels, 2015). Les expériences de rhéologie interfaciale confirment que cette méthode permet d’extraire les composés les plus tensioactifs présents aux interfaces eau-brut. Les analyses chimiques montrent que les IM sont partiellement composés d’asphaltènes et suggèrent que les composés contenant du soufre jouent un rôle important dans la stabilité des émulsions. Enfin, nous avons trouvé que les composés hydrosolubles transférés du brut à l’eau ont un comportement bénéfique, dans le sens où leur présence rend les émulsions eau-dans-brut moins stables. L’analyse FTMS de ces composés montre qu’ils appartiennent aux classes d’hétéroatomes suivant : O2, O3, S1, OS et O2S2 et qu’une partie de ces composés appartient à la classe des asphaltènes. / Crude oil recovery and refining operations rely on high consumption water processes, which may induce the formation of stable water-in-oil emulsions. Although asphaltenes and resins are known to influence the stability of crude oil emulsions, much is still unknown about the real composition of the w/o interfacial layer. Therefore, identifying these molecules and understanding their impact on the w/o interfacial properties are key points for better predicting emulsion problems in the petroleum industry. This thesis presents results on water/oil (w/o) interface characterization using shear and dilatational interfacial rheology as well as results on molecular characterization (GPC-ICP-HRMS and FTMS) of the crude oil interfacial material (IM) and of the amphiphilic crude oil species, which are transferred to the aqueous phase during the emulsification process. Four crude oils forming w/o emulsions of different stability were used in this study. Shear interfacial rheology experiments showed that most of the studied w/o interfaces were capable of forming an elastic interfacial network exhibiting shear elasticity G. A non-null G value interferes on drop deformation and thus on drop shape analysis (DSA) results. Nevertheless, the dilatational elasticity modulus measured by DSA (Eapp) was found to be representative of the sum of the Gibbs modulus plus 2 times G, as long as G  10 mN/m. This condition is generally satisfied since the asphaltene network is broken during dilatational experiments. Consequently, Eapp gives a good approximation of the real Gibbs modulus of the interface. A new phenomenological equation was proposed to fit the dilatational Eapp experimental data, allowing the assignment of a unique characteristic time to describe the w/o interfacial relaxation process and thus sample comparison. The IM of the crude oils was extracted using the “wet silica method” recently developed by Jarvis et al. (Energy Fuels, 2015). Results showed that this method collects the most-surface active compounds that adsorb in the time frame of the extraction procedure. Successive extractions collected species that were larger and less concentrated in the crude oil, but with higher adsorption energies. Molecular characterization revealed that the IM was partially composed of asphaltene compounds, and suggested that sulfur-containing compounds may play a major role in emulsion stability. Lastly, the oil-to-water transferred species were proven to impact the w/o interfacial properties and emulsion stability. Interestingly, concentrating these water-soluble species led to more efficient crude oil dehydration. FTMS analysis of the transferred species revealed that part of the compounds belonged to O2, O3, S1, OS and O2S2 heteroatom classes, and some of them have an asphaltene-type of molecules classification.
52

Application Of Electrokinetics In Subsurface Energy Extraction

Peraki, Maria 01 January 2017 (has links)
The world’s growing population results in increased energy needs that cannot yet be fully supported by the renewable sources of energy. These modern conditions and restraints have created the need to further research methods to enhance the recovery of resources previously unavailable due to technical and/or economic reasons and to reduce the environmental impacts of using fossil fuels. In this dissertation, applications of electrokinetic phenomena for the improvement of subsurface energy resource extraction are investigated using experimental and numerical tools. Electrodialysis is proposed as a method of pre-treatment of the flow-back water produced during fracturing stage of shale gas extraction. The method targets the reduction of Total Dissolved Solids levels in the flow-back water so that it can either be treated further or be reused directly. The treatment and reuse of the flow-back water can potentially improve the sustainability of the shale gas extraction, controlling the amounts of water used and the general environmental footprint of the process. In addition, the electrically assisted oil recovery is investigated as a potential technique for the enhancement of oil extraction, especially for the case of heavy crude oil. The high viscosity and low mobility of heavy crude oil render it almost impossible or not economical to extract. The method uses the application of low electrical field (direct current) to the oil reservoir to facilitate and increase the oil recovery by taking advantage of the mechanisms involved in electrokinetic phenomena.
53

Světový obchod s ropou / World Trade in Crude Oil

Benešová, Nela January 2015 (has links)
This master´s thesis deals with trade with crude oil and its impact on the world economy. Everyone, who wants to start to trade with crude oil, should find out basic terminology and information about crude oil that is characterized in the first chapter. The hunt for oil started many years ago, therefore the history is also mentioned in this master´s thesis. The second chapter focuses on the world trade with crude oil. Territorial structure and trade flows are described in this part of the master´s thesis. Nevertheless, the crude oil also has an impact on the world economy and economies of single states. The third chapter analyses states, where the inhabitants live beyond means of people from other countries but these states are so depended on crude oil that if this trade stopped, these countries would go bankrupt. However, there are also exceptions. Even though, there are states that have huge sources of crude oil, they still have to deal with financial problems. The forth chapter characterizes the trade with crude oil of the Czech Republic because it is a net importer of crude oil and the last chapter focuses on new trends in crude oil such as shale oil and trading at a crude oil market.
54

Predição de rendimentos de derivados de petróleo a partir de análises de destilação pelo método ASTM D7169 e DHA Front End realizadas em misturas de petróleos / Yield prediction of crude oil fractions using distillation analysys analysys

Borges, Fábio Luiz, 1984- 24 August 2018 (has links)
Orientador: Maria Regina Wolf Maciel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-24T13:22:45Z (GMT). No. of bitstreams: 1 Borges_FabioLuiz_M.pdf: 1928972 bytes, checksum: 8ee551cc8034ad570e84bd024b3702ca (MD5) Previous issue date: 2014 / Resumo: Essa dissertação tem como objetivo avaliar a utilização de curvas de destilação simulada de petróleo analisadas por dois métodos cromatográficos (ASTM D7169 e DHA Front End) combinados em um modelo de predição de rendimentos de derivados de uma unidade de destilação atmosférica e a vácuo. Os métodos utilizados são de execução mais ágil e de custo bastante reduzido em relação aos métodos de obtenção de curvas de Ponto de Ebulição Verdadeiro (PEV), sendo viável obter curvas de destilação de tanques de petróleo em laboratórios de refinarias. A utilização dessas análises possibilita a obtenção de curvas das cargas a serem processadas mais representativas do que as curvas obtidas utilizando as curvas PEV disponíveis no BDAP (Banco de Dados de Avaliação de Petróleos da Petrobras) em conjunto com a proporção de petróleos informada pelo BDEMQ (Banco de Dados de Estoque, Movimentação e Qualidade da Petrobras) em cada tanque. Para realizar essa avaliação, foi elaborada, no software PETROSIM®, uma simulação do tipo Distop, a qual foi calibrada utilizando-se as vazões e as curvas de destilação dos derivados amostrados em uma das plantas de destilação da Refinaria de Paulínia. Em seguida, foram coletadas amostras de tanques de petróleo, as quais foram analisadas pelos dois métodos combinados para obter as curvas de destilação, que foram utilizadas como dados de entrada da simulação calibrada, obtendo os rendimentos dos derivados. Foram também obtidos os rendimentos da mesma simulação calibrada utilizando como dados de entrada os dados de curvas PEV disponíveis no BDAP e também pelo método de predição baseado em rendimentos fixos de petróleos, que são gerados pelo software Blend-BR®, de propriedade da Petrobras, cujos dados de entrada também são as curvas PEV do BDAP. Os rendimentos obtidos por esses três métodos foram comparados com os rendimentos obtidos na unidade quando os tanques de petróleo amostrados foram processados. Os resultados obtidos indicaram que a simulação calibrada utilizando os dados analisados pelos métodos cromatográficos forneceu rendimentos mais aderentes aos realizados do que os outros métodos, principalmente na predição de rendimentos de nafta / Abstract: This thesis aims to evaluate the use of crude distillation curves analyzed by two combined chromatographic methods (ASTM D7169 and DHA Front End) combined into an atmospheric and vacuum crude distillation unit yields prediction model. These methods are faster to be executed and have the costs pretty lower compared to the methods used to obtain the True Boiling Point (TBP) curves, enabling to obtain distillation curves of crude tanks in refinery laboratories. These analyzes enable obtaining curves of the loads to be processed more representative than the curves obtained using the TBP curves available in BDAP (the Petrobras petroleum Database) and the proportion of oils informed by BDEMQ (the Petrobras feedstocks and quality Database) for each tank. To perform this evaluation, it was built in PETROSIM® software a Distop simulation, which was calibrated using flow rates and crude cuts distillation curves from the samples collected at on of the crude distillation units of Paulínia Refinery. Samples of oil tanks, which were analyzed by the two combined methods to obtain the distillation curves, were then used as input data the calibrated simulation, obtaining the crude cuts yields. The cuts yields were also obtained by the same calibrated simulation using as input data TBP curves available at BDAP and also by a model based on fixed crude cuts yields, which are performed by the software Blend-BR®, property of Petrobras, whose data input are also the TBP curves available at BDAP. The yields obtained by these three methods were compared with the yields obtained in the industrial unit when the sampled oil tanks were processed. The results indicated that the calibrated simulation using data analyzed by the chromatographic methods provided yields that are closer to actual ones than other methods, especially for the naphtha yields / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
55

Petroleômica por FT-ICR MS : avaliando a eficiência da ionização dos compostos polares de petróleo / Petroleomics by FT-ICR MS : evaluating the crude oil polar compounds ionization efficiency

Pudenzi, Marcos Albieri, 1990- 27 August 2018 (has links)
Orientador: Marcos Nogueira Eberlin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T06:50:00Z (GMT). No. of bitstreams: 1 Pudenzi_MarcosAlbieri_M.pdf: 6732140 bytes, checksum: 0b8176e8c477d9dca874d72376dfcae5 (MD5) Previous issue date: 2015 / Resumo: Esse trabalho tem como objetivo conhecer e avaliar a ionização dos compostos polares no petróleo for Espectrometria de Massas por Ressonância Ciclotrônica de Íons com Transformada de Fourier (FTICR MS do inglês Fourier Transform Ion Cyclotron Resonance Mass Spectrometry), relacionando essa ionização com parâmetros experimentais e características intrínsecas das moléculas. No Capítulo 1 o tipo de amostra de interesse (petróleo) é abordado, tanto em suas características quanto em sua análise, definindo petroleômica e sua função. A espectrometria de massas é apresentada, então, como ferramenta de grande utilidade nos estudos petroleômicos, em especial aquela de ultra alta resolução como FTICR MS (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) acoplada a fonte de ionização eletrospray (ESI). No Capítulo 2 a ferramenta estatística do planejamento de experimentos é apresentada e, então, utilizada em uma amostra real de petróleo de forma a relacionar os parâmetros operacionais da fonte de ESI com respostas avaliadas comumente em petroleômica. Aspectos interessantes das relações parâmetro-resposta surgem durante o estudo, mostrando que a análise de petróleo por ESI-FTICR MS, apesar de largamente utilizada na literatura, não é trivial e precauções devem ser tomadas durante a otimização dos parâmetros experimentais. No Capítulo 3 as técnicas de APCI (Atmospheric Pressure Chemical Ionization) e APPI (Atmospheric Pressure PhotoIonization) são abordadas e utilizadas, juntamente com ESI, para avaliar a ionização de padrões de compostos similares àqueles encontrados nas principais classes de compostos polares do petróleo. A análise pelas técnicas que ionizam de forma mais abrangente os compostos apresentaram comportamentos que tornam tais análises inviáveis. Uma reação de metilação que melhora a ionização de compostos sulfurados também é realizada em duas condições, comparando-se tais condições a partir dos espectros obtidos após suas análises. Conhecendo a ionização desses compostos padrões, é possível entender a petroleômica de forma mais ampla dando maior confiabilidade para estabelecer as relações composição-comportamento do petróleo / Abstract: The aim of this work is to know and evaluate the crude oil polar compounds ionization through Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, relating this ionization with experimental parameters and intrinsic characteristics of molecules. On Chapter 1 the sample of interest (crude oil) is addressed, both in its characteristics and its analysis, defining petroleomics and its function. Mass spectrometry is then presented as a tool of great utility in petroleomic studies, in special the ultra high resolution one as FTICR MS coupled to eletrospray Ionization (ESI). On Chapter 2 the design of experiment statistic tool is presented and used in a real crude oil sample in order to relate operational parameters of ESI source to commonly evaluated responses in petroleomics. Interesting aspects regarding parameter-response relationships arises during the study, showing that the crude oil analysis using ESI-FTICR MS, while it is largely used in literature, it is not trivial and precautions have to be taken during the optimization of experimental parameters. On Chapter 3 APCI (Atmospheric Pressure Chemical Ionization) and APPI (Atmospheric Pressure PhotoIonization) technics are addressed and used, along with ESI, to evaluate the ionization of standard compounds similar to those polar compounds found in crude oil. Analysis using sources that ionizes in the most comprehensive way has shown such behavior that makes the analysis unviable. A methylation reaction that improves the ionization of sulfur compounds is also made on two conditions, comparing these conditions through the obtained spectra after their analysis. By knowing the ionization of these standard compounds it is possible to understand the petroleomics in a much comprehensive way, providing reliability to stablish composition-behavior relations of crude oil / Mestrado / Quimica Organica / Mestre em Química
56

Hydrothermal conversion of agricultural and food waste

Makhado, Tshimangadzo January 2022 (has links)
>Magister Scientiae - MSc / The global dependence on non-renewable fossil fuels to meet energy needs cannot be sustained for a long time and it is already evident in the escalation of fuel prices over the past decade. This research was performed towards renewable energy production from agricultural and food waste. The use of agricultural and food waste has benefits such as being grown in a land that is not in competition with food crops protein, all year round availability, and having high lipid content. The produced bio-crude oil can be upgraded to remove moisture and acidity level, and can be used as a substitute for heavy oils such as diesel to power static appliances or can be used as petrol distillate fuel alternative. Hydrothermal liquefaction (HTL) process is one of the commonly used technologies for converting agricultural and food waste into liquid biofuels.
57

An Analysis of the Naphtha Cut of Cooke county, Texas, Crude Oil

Jones, Homer 08 1900 (has links)
This study attempted to determine hydrocarbons in the crude oil by comparing the results obtained using the two methods of analysis: chemical analysis and Kurtz-Headington analysis. The Kurtz-Headington analysis was found to be adequate to determine hydrocarbons in the crude oil.
58

Detoxification of crude oil

Jarullah, A.T., Mujtaba, Iqbal M., Wood, Alastair S. 22 December 2017 (has links)
No / Petroleum contributes significantly to our lives and will continue do so for many years to come. Petroleum derivatives supply more than 50% of the world's total supply of energy (Jarullah, 2011). Traditionally crude oil goes though fractional distillation to produce different grades of fuel such as gasoline, kerosene, diesel oil, etc. providing fuel for automobiles, tractors, trucks, aircraft, and ships. Catalytic hydrotreating (HDT) is used to detoxify the oil fractions produced by fractional distillation in the petroleum refining industries which involve removal of pollutants such as sulfur, nitrogen, metals, and asphaltene in trickle bed reactors. Recently Jarullah and co-workers proposed detoxification of whole crude oil a priori before the crude oil enters further processing in a fractionating column. This chapter highlights this new technology.
59

Improvement of the middle distillate yields during crude oil hydrotreatment in a trickle-bed reactor

Jarullah, Aysar Talib, Mujtaba, Iqbal M., Wood, Alastair S. January 2011 (has links)
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. Hydrotreatment (HDT) of crude oil is one of the most challenging tasks in the petroleum refining industry, which has not been reported widely in the literature. In this work, crude oil was hydrotreated upon a commercial cobalt¿molybdenum on alumina (Co¿Mo/¿-Al2O3) catalyst presulfided at specified conditions. Detailed pilot-plant experiments were conducted in a continuous-flow isothermal trickle-bed reactor (TBR), and the main hydrotreating reactions were hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeasphaltenization (HDAs), and hydrodemetallization (HDM), which includes hydrodevanadization (HDV) and hydrodenickelation (HDNi). The reaction temperature (T), the hydrogen pressure (P), and the liquid hourly space velocity (LHSV) were varied with certain ranges, with constant hydrogen to oil (H2/Oil) ratio. The effects of T, P, and LHSV on the conversion of sulfur, nitrogen, vanadium, nickel, and asphaltene were studied. The results showed that high T and P and low LHSV in HDS, HDN, HDV, HDNi, and HDAs of crude oil improve the sulfur (S), nitrogen (N), metals [vanadium (V) and nickel (Ni)], and asphaltene (Asph) conversion. The hydrotreated crude oil has been distilled into the following fractions: light naphtha (LN), heavy naphtha (HN), heavy kerosene (HK), light gas oil (LGO), and reduced crude residue (RCR), to compare the yield of these fractions produced by distillation after the HDT process to those produced by conventional methods (i.e., HDT of each fraction separately after the distillation). The yield of the middle distillate showed greater yield compared to the middle distillate produced by conventional methods. The properties of RCR produced using both methods are also discussed.
60

Part I: Design and Synthesis of Organic Materials for Dye Sensitized Solar Cells Part II: Qualitative and Semi-Quantitative Study of the Behavior of Surfactant on Crude Oil Recovery Processes

Pinnawala Arachchilage, Gayani Wasana Premathilake 02 August 2010 (has links)
No description available.

Page generated in 0.0371 seconds