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  • 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.
31

Syntheses, characterization and kinetics of nickel-tungsten nitride catalysts for hydrotreating of gas oil

Botchwey, Christian 21 July 2010
This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.
32

Syntheses, characterization and kinetics of nickel-tungsten nitride catalysts for hydrotreating of gas oil

Botchwey, Christian 21 July 2010 (has links)
This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.
33

Rederiers hantering av nya miljökrav : En studie om Birka Cruises, Tallink Silja och Viking Lines arbete med ekonomisk och miljömässig hållbar utveckling

Ahlström, Annika, Moreira, Marianna, Fernandes, Sabrina January 2014 (has links)
The purpose of this study is to examine how Viking Line, Tallink Silja and Birka Cruises work with economic and environmental sustainability, and also to see how they work with new environmental legislations. In 2015 a new environmental legislation will be introduced, by the name Sulphur directive. The Sulphur directive entails a reduction in Sulphur dioxide emissions from ships where the emissions cannot exceed 0,1 percent. There are three alternatives to achieve the new environmental legislation, the use of Marine Gas Oil, LNG or scrubbers. All three alternatives will lead to increasing costs for the shipping industry. The three companies exerts its shipping traffic in the Baltic Sea, a sea that is highly sensitive to external impacts. In the study qualitative methods were used, three personal interviews and five telephone interviews. Five theories were used to understand how the companies work, their estimations and their decisions: Strategic Tourism Planning Process, the Triple Bottom Line, the COSO model, The Decision-making Process and Responsible Cruise Tourism. The results of the study show that all three companies are facing an uncertain economic sustainable future and the deciding factors will be technological development, fuel prices and competitiveness.
34

[en] DETERMINATION OF NITROGEN AROMATIC COMPOUNDS IN DIESEL OIL AND GAS OIL BY MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY AND MICROEMULSION ELECTROKINETIC CHROMATOGRAPHY / [pt] DETERMINAÇÃO DE COMPOSTOS AROMÁTICOS NITROGENADOS EM ÓLEO DIESEL E EM GASÓLEO POR CROMATOGRAFIA CAPILAR ELETROCINÉTICA MICELAR E POR CROMATOGRAFIA ELETROCINÉTICA EM MICROEMULSÃO

ANASTACIA SA PINTO DA SILVA 30 May 2018 (has links)
[pt] No presente trabalho foram desenvolvidos dois métodos analíticos baseados na eletroforese capilar (EC), visando a identificação e quantificação de treze compostos policíclicos aromáticos nitrogenados (CAN) em amostras de óleo diesel e gasóleo. As variantes de EC usadas foram a cromatografia capilar eletrocinética micelar (MECC) e a cromatografia eletrocinética em microemulsão (MEEKC). Os compostos estudados foram indol (I), 2-metilindol (2MI), 3-metilindol (3MI), 7-metilindol (7MI), quinolina (QNL), 7,8-benzoquinolina (78BQ), acridina (ACR), carbazol (CBZ), 3-etilcarbazol (3EC), 9-metilcarbazol (9MC), 9-etilcarbazol (9EC), N,N-dimetilanilina (A) e N-metilpirrol (P). As condições experimentais para os dois métodos foram ajustadas visando, quando possível, a separação entre os treze analitos, possibilitando a determinação de cada um deles na amostra. Em MECC utilizou-se eletrólito contendo ácido bórico, dodecilsulfato de sódio (SDS), ureia e acetonitrila (ACN). Os limites instrumentais de quantificação ficaram entre 1,0 e 7,8 mg L(-1). A análise de amostra fortificada com os analitos produziu valores de recuperação entre 85 e 106 por cento. O modo MEEKC utilizou eletrólito contendo acetato de etila, butan-1-ol, SDS e tetraborato de sódio. Os limites instrumentais de quantificação ficaram entre 0,3 e 5,6 mg L(-1). A análise de amostra fortificada com os analitos produziu valores de recuperação entre 89 e 103 por cento. / [en] In the present work two analytical methodologies in capillary electrophoresis (CE) were developed aiming the identification and quantification of thirteen nitrogen polycyclic aromatic compounds (NPAC) in diesel oil and gas oil samples. The two methodologies studied were micellar electrokinetic capillary chromatography (MECC) and microemulsion electrokinetic chromatography (MEEKC). The studied compounds were indole (I), 2-methylindole (2MI), 3-methylindole (3MI), 7-methylindole (7MI), quinoline (QNL), 7,8-benzoquinoline (78BQ), acridine (ACR), carbazole (CBZ), 3-ethylcarbazole (3EC), 9-methylcarbazole (9MC), 9-ethylcarbazole (9EC), N,N-dimethylaniline (A) e N-methylpirrole (P). The experimental conditions to both methods were adjusted aiming the separation of all analytes in a way to provide individual determination on samples. In MECC the background electrolyte was composed of boric acid, sodium dodecylsulphate (SDS), ureia e acetonitrile (ACN). Instrumental limits of quantification were from 1.0 to 7.8 mg L(-1). The fortified sample analysis produced recoveries values from 85 to 106 per cent. In MEEKC the background electrolyte was composed of ethyl acetate, butan-1-ol, SDS and sodium tetraborate. Instrumental limits of quantification were from 0.3 to 5.6 mg L(-1). The fortified sample analysis produced recoveries values from 89 to 103 per cent.
35

Otimização da co-pirólise de gasóleo pesado com embalagens de PEAD pós-uso utilizando planejamento fatorial / Optimization co-pyrolysys from HDPE and heavy gas oil using factorial design methodology

Ney Joppert Junior 07 January 2015 (has links)
A co-pirólise é uma rota promissora, uma vez que minimiza o impacto ambiental causado pela disposição do plástico de maneira inadequada, evita seu acúmulo em lixões e permite um melhor aproveitamento de um recurso natural não-renovável, o petróleo, matéria prima importante para a geração de energia e obtenção de produtos químicos. O presente trabalho teve como objetivo a definição das condições experimentais mais propícias à obtenção de líquidos pirolíticos com alta fração de óleo diesel, resultantes da co-pirólise de polietileno de alta densidade (PEAD) pós-consumo com gasóleo pesado tilizando-se catalisador de FCC (Fluid Catalytic Cracking). Como instrumento de otimização das condições experimentais, optou-se pela Metodologia Planejamento Fatorial. Foi também estudado o efeito das condições experimentais, como: a temperatura de reação, a relação gasóleo/polietileno e a quantidade de catalisador no meio reacional. As amostras de polietileno, gasóleo e catalisador foram submetidas à co-pirólise em sistema de leito fixo, sob fluxo constante de nitrogênio, variando-se a temperatura entre 450 C a 550 C, a quantidade de PEAD no meio reacional foi de 0,2 a 0,6 g, e a quantidade de catalisador foi de zero a 0,06 g, mantendo-se fixa a quantidade de gasóleo em 2 g. Foram efetuadas as caracterizações física e química do gasóleo, polietileno pós-uso e do catalisador. Como resultado, obteve-se a produção de 87% de fração de óleo diesel em duas condições diferentes: (a) 550 0C de temperatura sem catalisador; (b) 500 0C de temperatura e 25% de catalisador FCC. Em ambos os casos, a quantidade de gasóleo pesado e PEAD foram constantes (2 g Gasóleo; 0,2 g PEAD), assim com o tempo de reação de 15 minutos. A fração de óleo diesel obtida neste estudo alcançou o poder calorífico de 44,0 MJ/Kg que é similar ao óleo diesel comercial. É importante ressaltar que em ambos os casos nenhum resíduo foi produzido, sendo uma rota ambientalmente importante para reciclagem de embalagens plásticas contaminadas com óleo lubrificante originárias de postos de serviço, visando à recuperação de ambos conteúdo energético e orgânico dos resíduos de embalagens plásticas pós-uso / In this work it was studied the co-pyrolysis process applied to HDPE plastic package with motor oil residues with Heavy Gas Oil and FCC Catalyst. The main objective of this work was to find the experimental conditions that enhanced the diesel fuel fraction in the pyrolitic oil. Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and heavy gas oil (HGO) through copyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.0 g) in all experiments. The model optimum conditions were determined to be temperature of 550 C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25 %) with a lower temperature (500 C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. The diesel fuel fraction obtained in this study achieved heating value (44.0 MJ/Kg) similar to commercial diesel oil. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments. Based on experimental results, co-pyrolysis can represent a significant role in future in the recovery of both energetic and organic content of HDPE plastic package with motor oil residues
36

Otimização da co-pirólise de gasóleo pesado com embalagens de PEAD pós-uso utilizando planejamento fatorial / Optimization co-pyrolysys from HDPE and heavy gas oil using factorial design methodology

Ney Joppert Junior 07 January 2015 (has links)
A co-pirólise é uma rota promissora, uma vez que minimiza o impacto ambiental causado pela disposição do plástico de maneira inadequada, evita seu acúmulo em lixões e permite um melhor aproveitamento de um recurso natural não-renovável, o petróleo, matéria prima importante para a geração de energia e obtenção de produtos químicos. O presente trabalho teve como objetivo a definição das condições experimentais mais propícias à obtenção de líquidos pirolíticos com alta fração de óleo diesel, resultantes da co-pirólise de polietileno de alta densidade (PEAD) pós-consumo com gasóleo pesado tilizando-se catalisador de FCC (Fluid Catalytic Cracking). Como instrumento de otimização das condições experimentais, optou-se pela Metodologia Planejamento Fatorial. Foi também estudado o efeito das condições experimentais, como: a temperatura de reação, a relação gasóleo/polietileno e a quantidade de catalisador no meio reacional. As amostras de polietileno, gasóleo e catalisador foram submetidas à co-pirólise em sistema de leito fixo, sob fluxo constante de nitrogênio, variando-se a temperatura entre 450 C a 550 C, a quantidade de PEAD no meio reacional foi de 0,2 a 0,6 g, e a quantidade de catalisador foi de zero a 0,06 g, mantendo-se fixa a quantidade de gasóleo em 2 g. Foram efetuadas as caracterizações física e química do gasóleo, polietileno pós-uso e do catalisador. Como resultado, obteve-se a produção de 87% de fração de óleo diesel em duas condições diferentes: (a) 550 0C de temperatura sem catalisador; (b) 500 0C de temperatura e 25% de catalisador FCC. Em ambos os casos, a quantidade de gasóleo pesado e PEAD foram constantes (2 g Gasóleo; 0,2 g PEAD), assim com o tempo de reação de 15 minutos. A fração de óleo diesel obtida neste estudo alcançou o poder calorífico de 44,0 MJ/Kg que é similar ao óleo diesel comercial. É importante ressaltar que em ambos os casos nenhum resíduo foi produzido, sendo uma rota ambientalmente importante para reciclagem de embalagens plásticas contaminadas com óleo lubrificante originárias de postos de serviço, visando à recuperação de ambos conteúdo energético e orgânico dos resíduos de embalagens plásticas pós-uso / In this work it was studied the co-pyrolysis process applied to HDPE plastic package with motor oil residues with Heavy Gas Oil and FCC Catalyst. The main objective of this work was to find the experimental conditions that enhanced the diesel fuel fraction in the pyrolitic oil. Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and heavy gas oil (HGO) through copyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.0 g) in all experiments. The model optimum conditions were determined to be temperature of 550 C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25 %) with a lower temperature (500 C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. The diesel fuel fraction obtained in this study achieved heating value (44.0 MJ/Kg) similar to commercial diesel oil. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments. Based on experimental results, co-pyrolysis can represent a significant role in future in the recovery of both energetic and organic content of HDPE plastic package with motor oil residues
37

Caractérisation et réactivité en hydrotraitement des composés hétéroatomiques présents dans les distillats sous vide du pétrole / Characterization and reactivity of heteroatomic compounds contained in vacuum gas oil

Boursier, Laure 13 February 2014 (has links)
Dans le domaine pétrolier, l'exploitation de pétroles bruts de plus en plus lourds nécessite de développer des procédés de conversion de ces coupes lourdes en bases carburants valorisables. Parmi ces procédés, l'hydrocraquage permet d'obtenir à partir d'une coupe distillat sous vide (DSV) des gazoles de grande qualité. Afin d'améliorer la compréhension de ce procédé catalytique, une caractérisation détaillée des charges et effluents de ce procédé est nécessaire. Les techniques existantes n'étant pas assez performantes, ce travail de thèse s'est focalisé sur l'utilisation de la chromatographie en phase gazeuse bidimensionnelle haute température (GC×GC-HT) et de la spectrométrie de masse haute résolution à transformée de Fourier (FT-ICR/MS). Il a ainsi été montré que la GC×GC-HT pouvait être utilisée pour éluer des composés ayant des points d'ébullition équivalents au nC68 (641 °C). Ce travail a également permis de proposer une méthode de caractérisation des composés soufrés par familles en GC×GC-HT-SCD dont les résultats sont cohérents avec les données obtenues par FT-MS. Pour les composés azotés, les limites de la GC×GC en terme de séparation ont été atteintes malgré la mise en place d'une pré-séparation en ligne par SFC. Une méthodologie de quantification par famille à partir de la FT-MS a alors été proposée pour étudier sélectivement les composés azotés basiques (mode ESI+) ou neutres (mode ESI-). Ce travail a permis de proposer de nouveaux outils analytiques de caractérisation des DSV et de confirmer la nature chimique des familles les plus réfractaires à l'hydrotraitement, à savoir les composés fortement alkylés de type dibenzothiophène et carbazole. / Converting heavy petroleum cuts into valuable fuels becomes a strong necessity for the refining industry as crude oil quality globally decreases. Among all the conversion processes, vacuum gas oil (VGO) hydrocracking is certainly the most suitable process to convert VGOs into high quality diesel fuel.In order to improve the understanding of this catalytic process, a detailed characterization of VGO feeds and products is needed. As existing analytical methods are not currently powerful enough, this work focused on the use of high-temperature comprehensive bidimensional gas chromatography (HT-GC×GC) and Fourier-transform high resolution mass spectrometry (FT-ICR/MS). First, it was shown that HT-GC×GC can elute heavy boiling point compounds up to nC68 (641 °C). Moreover, a HT-GC×GC-SCD method was developed to characterize sulfurcontaining compounds according to their chemical family. The obtained results were in accordance with parallel FT-ICR/MS measurements for sulfur compounds. For nitrogen-containing compounds, separation limits of HTGC×GC-NCD were reached despite the use of an additional online pre-separation by supercritical fluid chromatography (SFC). Therefore, a FT-MS based methodology was proposed to quantify nitrogen-containing chemical families and study basic and neutral compounds with ESI(+) and ESI(-) respectively.Hence, this work proposed innovative analytical tools for the characterization of vacuum gas oils. It also confirmed that highly-alkylated dibenzothiophenes and carbazoles were the most refractory sulfur and nitrogen-containing compounds towards hydrotreatment.
38

Investigation of Nanopore Confinement Effects on Convective and Diffusive Multicomponent Multiphase Fluid Transport in Shale using In-House Simulation Models

Du, Fengshuang 28 September 2020 (has links)
Extremely small pore size, low porosity, and ultra-low permeability are among the characteristics of shale rocks. In tight shale reservoirs, the nano-confinement effects that include large gas-oil capillary pressure and critical property shifts could alter the phase behaviors, thereby affecting the oil or gas production. In this research, two in-house simulation models, i.e., a compositionally extended black-oil model and a fully composition model are developed to examine the nano-pore confinement effects on convective and diffusive multicomponent multiphase fluid transport. Meanwhile, the effect of nano-confinement and rock intrinsic properties (porosity and tortuosity factor) on predicting effective diffusion coefficient are investigated. First, a previously developed compositionally extended black-oil simulation approach is modified, and extended, to include the effect of large gas-oil capillary pressure for modeling first contact miscible (FCM), and immiscible gas injection. The simulation methodology is applied to gas flooding in both high and very low permeability reservoirs. For a high permeability conventional reservoir, simulations use a five-spot pattern with different reservoir pressures to mimic both FCM and immiscible displacements. For a tight oil-rich reservoir, primary depletion and huff-n-puff gas injection are simulated including the effect of large gas-oil capillary pressure in flow and in flash calculation on recovery estimations. A dynamic gas-oil relative permeability correlation that accounts for the compositional changes owing to the produced gas injection is introduced and applied to correct for changes in interfacial tension (IFT), and its effect on oil recovery is examined. The results show that the simple modified black-oil approach can model well both immiscible and miscible floods, as long as the minimum miscibility pressure (MMP) is matched. It provides a fast and robust alternative for large-scale reservoir simulation with the purpose of flaring/venting reduction through reinjecting the produced gas into the reservoir for EOR. Molecular diffusion plays an important role in oil and gas migration in tight shale formations. However, there are insufficient reference data in the literature to specify the diffusion coefficients within porous media. Another objective of this research is to estimate the diffusion coefficients of shale gas, shale condensate, and shale oil at reservoir conditions with CO2 injection for EOR/EGR. The large nano-confinement effects including large gas-oil capillary pressure and critical property shifts could alter the phase behaviors. This study estimates the diffusivities of shale fluids in nanometer-scale shale rock from two perspectives: 1) examining the shift of diffusivity caused by nanopore confinement effects from phase change (phase composition and fluid property) perspective, and 2) calculating the effective diffusion coefficient in porous media by incorporating rock intrinsic properties (porosity and tortuosity factor). The tortuosity is obtained by using tortuosity-porosity relations as well as the measured tortuosity of shale from 3D imaging techniques. The results indicated that nano-confinement effects could affect the diffusion coefficient through altering the phase properties, such as phase compositions and densities. Compared to bulk phase diffusivity, the effective diffusion coefficient in porous shale rock is reduced by 102 to 104 times as porosity decreases from 0.1 to 0.03. Finally, a fully compositional model is developed, which enables us to process multi-component multi-phase fluid flow in shale nano-porous media. The validation results for primary depletion, water injection, and gas injection show a good match with the results of a commercial software (CMG, GEM). The nano-confinement effects (capillary pressure effect and critical property shifts) are incorporated in the flash calculation and flow equations, and their effects on Bakken oil production and Marcellus shale gas production are examined. The results show that including oil-gas capillary pressure effect could increase the oil production but decrease the gas production. Inclusion of critical property shift could increase the oil production but decrease the gas production very slightly. The effect of molecular diffusion on Bakken oil and Marcellus shale gas production are also examined. The effect of diffusion coefficient calculated by using Sigmund correlation is negligible on the production from both Bakken oil and Marcellus shale gas huff-n-puff. Noticeable increase in oil and gas production happens only after the diffusion coefficient is multiplied by 10 or 100 times. / Doctor of Philosophy / Shale reservoir is one type of unconventional reservoir and it has extremely small pore size, low porosity, and ultra-low permeability. In tight shale reservoirs, the pore size is in nanometer scale and the oil-gas capillary pressure reaches hundreds of psi. In addition, the critical properties (such as critical pressure and critical temperature) of hydrocarbon components will be altered in those nano-sized pores. In this research, two in-house reservoir simulation models, i.e., a compositionally extended black-oil model and a fully composition model are developed to examine the nano-pore confinement effects on convective and diffusive multicomponent multiphase fluid transport. The large nano-confinement effects (large gas-oil capillary pressure and critical property shifts) on oil or gas production behaviors will be investigated. Meanwhile, the nano-confinement effects and rock intrinsic properties (porosity and tortuosity factor) on predicting effective diffusion coefficient are also studied.
39

Approche multitechnique des phénomènes de diffusion en hydrotraitement de distillats / Multi-technical study of diffusion phenomena in vacuum gas oil hydrotreatment

Kolitcheff, Svetan 03 March 2017 (has links)
Dans l'industrie du raffinage, les procédés de craquage catalytique permettent la production de carburants à partir de coupes pétrolières lourdes, telles que les distillats sous vides (DSV). Pour optimiser ces procédés, un hydrotraitement préalable est nécessaire. Ces dernières années, les travaux conséquents de R&D ont considérablement amélioré l'activité des catalyseurs d'hydrotraitement. Par conséquent, le transfert de matière interne peut devenir limitant, il doit donc être quantifié.Une méthodologie utilisant la chromatographie inverse liquide a été développée afin de caractériser le transfert de matière dans des supports aluminiques de catalyseur. Le système a ensuite été déployé pour caractériser l'influence de l'adsorption, de la température et des précurseurs de la phase active. Dans des alumines mésoporeuses, le régime de diffusion est moléculaire pour des composés saturés allant des coupes essences au DSV. Ainsi, pour différentes alumines, des valeurs de tortuosité ont été estimées et corrélées aux propriétés texturales (porosité, surface spécifique et distribution en taille des pores). Ces relations montrent que les valeurs de tortuosité obtenues ne sont pas en accord avec un solide homogène vis-à-vis des propriétés de transfert de matière. Il y aurait donc une organisation dans la porosité des alumines.Un test catalytique en réacteur agité a aussi été développé pour étudier le transfert de matière en conditions réactives. L'impact de la taille des grains sur l'hydrodésulfuration d'une molécule synthétisée a été caractérisé et modélisé. Ces résultats ont été comparés aux expériences de chromatographie inverse avec un bon accord / The catalytic cracking has an important role in fuels production from heavy oil cuts like vacuum gas oil (VGO). To optimize these processes, a pre-hydrotreatment is required. The amount of work dealt by the research community in the last years has highly contributed to the enhancement of the catalyst’s activity. Therefore, the internal mass transfer can become the limiting step and it must be quantified.A methodology based on inverse liquid chromatography has been developed to characterize the mass transfer within alumina catalyst supports. The experimental setup was also used to study the influence of several parameters into mass transfer properties such as, adsorption, temperature, and active phase precursors. In mesoporous aluminas, the diffusion regime undertaken by saturated compounds, going from gasoline to VGO is the molecular regime. For different alumina supports, tortuosity values were estimated and correlated to the textural properties (porosity, specific surface area and pore size distribution). These results showed that the aluminas can not be considered as homogeneous supports given the estimated mass transfer properties. Thus, we assume that a hierarchical porous structure might be in cause. A catalytic test promoted in a stirred reactor was also developed to study the mass transfer properties under reactive conditions. The impact of the particle grains size into the hydrodesulphurization of a synthetized molecule was characterized and modeled. A good agreement was found between the data obtained using the inverse chromatography experiments and the catalytic tests
40

A Study of Flow Patterns and Surface Wetting in Gas-Oil-Water Flow

Kee, Kok Eng 24 September 2014 (has links)
No description available.

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