Carbonate rocks are of global importance as they contain about 50% of the world’s remaining hydrocarbon reserves and are also a major host to the world’s groundwater resources. Therefore, understanding and modelling the fluid flow processes in carbonates are of great importance. A critical problem is that, unlike homogenous media (such as sandstones), carbonates often show features, including porosity, that span across a wide spatial range, from sub-micron porosity to fractures of meters length-scale. In this study X-ray computed micro-tomography (μCT) has been utilised as a tool to monitor two phase (oil-brine) flow in porous carbonate (dolomite) plugs at ambient temperature and pressures smaller than 690 kPa. A simple, low-cost and highly X-ray transparent core-holder was utilised for which the design is introduced. Capillary end effects were recognised and avoided in data analysis. Displacement processes that occur in the dolomite under water-wet, oil-wet, and partially mixed-wet states were investigated. The experiments consisted of a series of drainage and imbibition processes occurring under capillary and viscous dominated flow regimes. Pore-scale mechanisms of piston-like displacement and snap-off (or at least clear results of them), that were previously observed in sandstones and 2D micro-models, were observed in the dolomite under study. In addition, a new pore-scale mechanism was identified which occurred at high capillary numbers, referred to as droplet-fragmentation. This new pore-scale mechanism may provide an explanation to the capillary-desaturation process for heterogeneous media. In the experiments performed on the oil-wet plug formation of a stable water in oil emulsion was observed which appears to be the first 3D observation of in situ emulsion formation made using μCT. Direct visualisation of the oil-brine-rock configurations and measurement of the contact angles are presented. A comparison was made for the contact angle distributions measured for the water-wet and oil-wet conditions. Observation of fluid displacement processes as well as oil-brine-rock contact angle distributions demonstrate that pore-scale imaging provides a promising tool for wettability characterisation on both pore and core scales. Such detailed wettability data can also be used in pore-scale flow models. For the dolomite under study multiple-scale pore network models were constructed by integrating single-scale networks extracted from μCT images acquired at different length-scales. Mercury injection capillary pressure laboratory measurements were used to evaluate the capillary pressure (vs. saturation) curves calculated using single, two-scale, and three-scale network models of this dolomite. The integrated networks displayed an improved match to the laboratory measurements in comparison with the single-scale network model. The three-scale network provided the closest simulated curve, this result confirms that a more representative model displays closer properties. While simulated capillary pressure curves are close (converging) for the integrated networks the calculated relative permeability curves show variability for different multiple-scale networks. The present work demonstrates that the pore-scale fluid displacement processes occurring in heterogeneous porous media are more complex than those occurring in homogeneous media. In addition, successful fluid flow simulations require construction of multiple-scale models as well as consideration of the pore-scale processes (such as droplet-fragmentation) that are specific to such complex pore systems.

67 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-11T17:32:00Z No. of bitstreams: 1 DISSERTACAO jeane quelle brito.pdf: 1136596 bytes, checksum: 8c3ba147541551b34feda989ad933110 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-05-10T18:05:25Z (GMT) No. of bitstreams: 1 DISSERTACAO jeane quelle brito.pdf: 1136596 bytes, checksum: 8c3ba147541551b34feda989ad933110 (MD5) / Made available in DSpace on 2013-05-10T18:05:25Z (GMT). No. of bitstreams: 1 DISSERTACAO jeane quelle brito.pdf: 1136596 bytes, checksum: 8c3ba147541551b34feda989ad933110 (MD5) Previous issue date: 2011 / A produção de biodiesel já é uma realidade no mundo, no entanto devido aos custos da produção, ainda não é um combustível economicamente competitivo. Nesse sentido, estudos de processos alternativos para a obtenção de biodiesel através da reação de transesterificação têm sido estudados com o objetivo de aumento de rendimento, redução do tempo de reação, diminuição do consumo de reagentes e diminuição de impactos ambientais. Esses estudos incluem o uso de irradiação ultrassônica, e a viabilização do emprego do etanol como insumo. A menor reatividade do álcool etílico em relação ao metanol torna a reação de transesterificação mais lenta, além de serem necessárias maiores temperaturas e excesso de álcool. A viabilização técnica do uso do etanol na produção do biodiesel pode contribuir de maneira efetiva na obtenção de biodiesel de fontes 100% renováveis e sustentável, considerando a produção consolidada de etanol no Brasil. A transesterificação para obtenção do biodiesel que ocorre entre o triacilglicerídeo e o álcool acontece na região de interface entre esses dois reagentes, uma vez que os mesmos são pouco miscíveis. O uso do ultrassom em processos químicos favorece tanto a transferência de massa, como também a própria reação, oferecendo assim reações com menor tempo, menor quantidade de reagentes e condições físicas mais brandas. O presente trabalho teve como objetivo estudar a utilização da irradiação ultrassônica como uma alternativa para superação das dificuldades encontradas para produção biodiesel utilizando a rota etílica. Para realização dos experimentos reacionais utilizou-se um processador ultrassônico de 750 watts equipado com sonda de titânio. Os experimentos foram conduzidos na presença de 250 g de óleo de soja (OS) e de óleo residual (OR), sem aquecimento externo e sob agitação mecânica constante. Foi realizado também um planejamento experimental fatorial de 2 níveis e 3 fatores (23), onde foram estabelecidos valores mínimos (-) e máximos (+) para estudo da influência dos fatores (I) razão óleo/etanol, (II) quantidade de catalisador e (III) tempo de sonicação na produção do biodiesel. Através dos resultados obtidos, foi possível mostrar que com o auxílio da irradiação do ultrassom é possível se obter biodiesel com qualidade adequada utilizando álcool etílico como insumo em tempos reacionais bastantes curtos. O uso de ultrassom mostrou ser uma alternativa promissora, uma vez que permitiu o uso de condições reacionais brandas de temperatura, sem utilização de grande excesso de etanol e obtenção de boas taxas de conversão. / Salvador

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Today's environmental problems require action on the part of mankind to minimize environmental pollution. One way to slow down such disturbance is the use of "clean" fuels like biofuels. Within this scope this work contributes by studying the production of biodiesel through the reuse of frying oil, which generates harmful waste. The present work was the transesterification of biodiesel from used frying oil by basic catalysis, via ethyl and methyl routes. Biodiesel has its physico-chemical variables studied and their optimal reaction. Through the technique of thermal expansion coefficients of methyl and ethyl biodieseis and the corresponding mathematical algorithms for each of biodieseis can observe significant differences between the mathematical models established assumptions compared to the results by EN 14214. The optimization of reaction conditions studied the variables: molar ratio (RM), speed, reaction time, catalyst type, catalyst concentration and temperature. Methylic biodiesel from frying oil (BMR) for the last two mentioned are the ones that were more operational importance, while for the ethylic biodiesel from frying oil (BER) of catalyst concentration and time are more relevant. The conditions of maximum yield were determined by factorial design: potassium hydroxide (KOH) as catalyst; RM de 7:1 alcohol:oil; rotation of 80 rpm, catalyst concentration of about 1.7% (m/m), temperature 48 ° C for the BMR, and 30 oC for the BER, and reaction time of 30 minutes for BER, and 60 minutes for BMR. The process sets a tolerance for the variables of greatest influence on the reaction, which means that small quantitative variations of individual conditions do not affect the overall yield. The content of free fatty acids changes the reaction yield, ethanolysis being more sensitive to this variable. The characterizations made to specifications for both biodiesel met the requirements of National Petroleum Agency (ANP). The thermogravimetric analysis showed the weight loss along with the volatilization and decomposition of the sample. The infrared showed the main bands related to methyl and ethyl esters. Chromatography confirmed the transformation of triglycerides into esters with high ester content of 99.99%. As the main composition of linoleic acid esters of about 46%, similar to soybean oil. / Atualmente os problemas ambientais requerem uma tomada de atitude por parte da humanidade no sentido de minimizar a poluição ambiental. Uma maneira de desacelerar tal perturbação é a utilização de combustíveis menos poluentes, como os biocombustíveis. Dentro dessa vertente este trabalho contribui através do estudo da produção de biodiesel através do reaproveitamento do óleo de fritura, pois o descarte indevido do óleo gera resíduos sólidos prejudiciais ao meio ambiente. No presente trabalho descreve-se a obtenção de biodiesel proveniente da transesterificação do óleo de fritura através da catálise básica, via rotas etílica e metílica. O biodiesel teve suas propriedades físico-químicas estudadas e suas variáveis de reação otimizadas. Através da técnica de coeficientes de dilatação térmica dos biodieseis metílicos e etílicos e os correspondentes algoritmos matemáticos, para cada um dos biodieseis pode observar diferenças significativas entre os modelos matemáticos estabelecidos confrontados com os resultados pressupostos pela norma EN 14214. Para a otimização das condições reacionais estudo-se as variáveis: razão molar (RM), rotação, tempo de reação, tipo de catalisador, concentração de catalisador e temperatura. Para o biodiesel metílico as duas últimas variáveis citadas, são as que revelaram maior importância operacional, enquanto que para o biodiesel etílico a concentração de catalisador e o tempo são mais relevantes. As condições de rendimento máximo determinado pelo planejamento fatorial foram: hidróxido de potássio (KOH) como catalisador; RM de álcool:óleo 7:1; rotação de 80 rpm; concentração do catalisador de aproximadamente 1,7% (m/m); temperatura de 48 oC, para o biodiesel metílico, e 30 oC, para o biodiesel etílico, e tempo de reação de 30 min, para biodiesel etílico, e 60 min, para biodiesel metílico. O processo apresenta uma tolerância para as variáveis de maior influência sobre a reação, o que significa que pequenas variações quantitativas individuais das condições não afetam significativamente o rendimento global. O teor de ácidos graxos livres altera o rendimento da reação, sendo a etanólise mais sensível a esta variável. Quanto às caracterizações feitas ambos biodieseis satisfizeram as exigências da Agência Nacional de Petróleo. A análise termogravimétrica mostrou a perda de massajuntamente com a volatilização e decomposição da amostra. O infravermelho revelou as principais bandas referentes aos ésteres metílicos e etílicos. A cromatografia confirmou a transformação dos triglicerídeos em ésteres, com alto teor de ésteres de 99,99%, sendo a principal composição em ésteres do ácido linoléico de aproximadamente 46%, semelhante ao óleo de soja. / Doutor em Química

Orientador: David de Carvalho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-12T07:40:33Z (GMT). No. of bitstreams: 1 PaschoalinFilho_JoaoAlexandre_D.pdf: 6669180 bytes, checksum: 78d0e0cf2f6cfc3054d3c7bdf89b2116 (MD5) Previous issue date: 2008 / Resumo: Apresenta-se neste trabalho o estudo do comportamento de diferentes tipos de estacas, implantadas em solo de diabásio, quando submetidas a esforços de tração, através da realização de provas de carga estática do tipo lenta. Foram executadas quatro estacas tipo raiz sendo uma de 23m de comprimento e 310 mm de diâmetro e três instrumentadas de 12m de comprimento com 410 mm de diâmetro; três estacas metálicas perfil I tipo W250x32,7, sendo uma com 12m e duas com 18m de comprimento; duas estacas tipo trilho TR37 sendo uma com 18m e outra de 20,5m de comprimento. Foram também estudadas as seguintes estacas já anteriormente instaladas no local em estudo: três estacas escavadas (sem lama bentonítica) de 12m de comprimento e 400 mm de diâmetro, três estacas tipo hélice contínua com 12m de comprimento e 400 mm de diâmetro, uma estaca tipo ômega de 12m de comprimento e 370 mm de diâmetro e uma estaca prémoldada de oncreto com 14m de comprimento e 180 mm de diâmetro. O local de execução das estacas foi o Campo Experimental para Estudos em Mecânica dos Solos e Fundações localizado dentro dos limites da Faculdade de Engenharia Agrícola da Unicamp (Universidade Estadual de Campinas), localizada no município de Campinas, interior de São Paulo. O subsolo do local é constituído por solo poroso de diabásio, cuja primeira camada de 6,5m de espessura é constituída de argila silto-arenosa, seguida de uma camada de silte arenoso e nível de água a 17m de profundidade. Foram utilizados os seguintes métodos para a estimativa da capacidade de carga próprios para esforços de tração como: Método do Tronco de Cone, Método do Cilindro de Atrito, Método de Meyerhoff (1973); Método de Kulhawy (1985); Método de Levacher & Sieffert (1984) e Método da Universidade de Grenoble de acordo com Martin (1963). Os valores de capacidade de carga estimados por meio de cada método foram então confrontados com os valores de carga máxima obtidos por meio das provas de carga. As resistências laterais totais de cada estaca foram determinadas por meio dos seguintes métodos semi-empíricos próprios para esforços de compressão: Décourt & Quaresma (1998); Décourt & Quaresma (1978); Aoki & Velloso (1975 - SPT); Aoki & Velloso (1975 - CPT); David Cabral (1986); P.P Velloso (1981); Teixeira (1996); Antunes & Cabral (1996); FUNDESP (1998) e Monteiro (2000). Os valores de resistência lateral obtidos pelos métodos foram comparados aos valores de carga máxima obtidos pelas provas de carga. As capacidades de carga a tração das estacas estudadas foram previstas por meio dos seguintes métodos próprios para extrapolação de curvas carga x recalque: Van der Veen (1953), Décourt (1996), NBR 6122/96 e Davisson (1978). Para os métodos de Van der Veen (1953) e Décourt (1996) foram estimadas cargas máximas a partir de pontos da curva carga x recalque situados até recalques referentes a cargas de 50, 60, 70, 80 e 90% das cargas máximas atingidas pelas provas. Este procedimento teve como objetivo verificar a aplicabilidade destes métodos caso as provas de carga fossem prematuramente interrompidas. Foram também previstos valores de recalques obtidos para cargas referentes a PC/2 por meio dos métodos de Vesic (1969, 1975a) e Poulos & Davis (1980). Foram também determinadas nesta pesquisa correlações matemáticas entre valores de atrito lateral médios para cada estaca estudada (rl), determinados por meio das provas de carga, e dados de resistência lateral obtidos utilizando-se parâmetros provenientes de ensaios de cone (CPT) e SPT-T, como fs (para CPT) e fTmáximo e fTmínimo (para SPT-T). / Abstract: This research presents the behavior of different kinds of piles conducted in unsaturated diabasic porous soil submitted to uplift forces. For this research there were built the follow piles: three instrumented root piles with 12m length and 410mm of nominal diameter, one root pile with nominal diameter of 310mm and 23m length, two metallic piles type W250x32.7 with 18 meters length, one metallic pile with 12m length and type W250x32.7, two trail piles TR37 type, one of them with 18 meters length and the other with 20.5 meters length. There were also considered in this research the follow piles already conducted at the studied area: three bored piles with 12 meters length and diameter of 400mm, three Continuous Flight Auger piles with 12 meters length and diameter of 400mm, one Omega pile with 12m length and diameter of 370mm and one Concrete Precast pile with 14 meter length and diameter of 180mm. The piles were built at the site for Experimental Studies in Soil Mechanics and Foundations. This experimental area is situated at the State University of Campinas, in the interior region of the state of São Paulo, Brazil. The local subsoil is basically composed by a superficial layer of approximately 6,5m thick composed of high porosity silt-sand clay followed by clayey-sandy silt. The water table is not checked until a depth of 17 meters. The carrying capacity of the studied piles was also provided by means of theoretical methods appropriate for uplift forces. The methods considered were: Method of the Trunk of Cone, Method of Cylinder of Friction, Meyerhoff (1973), Kulhawy (1985), Levacher & Sieffert (1984) and University of Grenoble in according to Martin (1963). The values estimated using the methods under consideration were compared to those obtained by means of the load tests. Methods for "load x settlement" curves extrapolation such as: Van der Veen (1953), Décourt (1998) and NBR 6.122 (1996) and Davisson (1973) were also used to provide the carrying capacity of the studied piles. There were also provided by Van der Veen (1953) and Décourt the ultimate loads for each using 50, 60, 70, 80 e 90% of the ultimate load obtained by means of the load tests. Semi-empirical methods, appropriate for compression forces, were also used considering only the portion of lateral resistance. The methods studied were the following: Décourt & Quaresma (1998); Décourt & Quaresma (1978); Aoki & Veloso (1975 - SPT); Aoki & Veloso (1975 - CPT); David Cabral (1986); P.P Velloso (1981); Teixeira (1996); Antunes & Cabral (1996); FUNDESP (1998) e Monteiro (2000). The obtained values of lateral resistance were compared to the maximum load obtained by means of the load tests. The settlements of the studied piles were also determinate by Vesic (1969, 1975a) and Poulos & Davis (1980). Mathematical correlations between lateral friction values, obtained by means of the load tests, and lateral resistance values obtained by means of field tests like SPT-T and CPT were also provided in this research. / Doutorado / Construções Rurais e Ambiencia / Doutor em Engenharia Agrícola

Currently, the problem of waste generation by human activities is complex and remains unraveled societies in general, especially in the urban context. For a better disposal of waste should be proposed to gather policy that besides the correct destination is able to build a sustainable population of the social and environmental point of view, by reducing the waste produced and the reuse and recycling of materials as alternative income. There are some problems from the improper disposal of a highly polluting residue, oils and saturated fats, which although at room temperature is present in the liquid state when it comes into contact with water, it becomes a solid residue; by its particularities when discarded improperly in the environment, creates problems of economic and environmental, and the contamination of soil and water resources and clogging pipes and sewage network, increasing maintenance costs of sanitation companies. One way to reuse the used cooking oil is the manufacture of new products such as biodiesel and soap, avoiding, thus, the improper disposal on the environment and, consequently, environmental pollution and harmfulness to human health. The sample of the survey sample comprised those responsible for private households in the domestic sphere, chosen randomly as two neighborhoods in the city of Itaara-RS, a total of 50 people interviewed. Thus, the study enabled us to diagnose and understand people's behavior on the cooking oil disposal used, with different social levels and their willingness to adhere to more sustainable practices of their disposal. In addition, examined the potential for payment of used cooking oil and highlighted the importance of selective collection of this waste to mitigate environmental impacts caused by it, when disposed of improperly. The research showed both the low-income neighborhood, and in the higher income, respondents said they would donate the oil to recycling because they are concerned about environmental protection and prevent pollution. It is noticed that much of the population is concerned with the environment, which is a favorable opinion for the involvement in the process of cooking oil collection used, avoiding their improper disposal. Still, the degree of willingness to donate the used oil is positive, respondents with lower income reported already enjoying the residue in soap and the use of animal food, which would be less willing to cooperate with donation campaigns used oil, since the material intended for its own use, for economic reasons. As part of this research, where the allocation of a polluting waste resulting from human activity is addressed, the environmental attitudes and perception of the sample, reveal the degree of awareness and awareness of their role in question disposal of cooking oil and the environment . It was possible to research the construction of a scenario of knowledge and expectations on the part of the population of Itaara front of the issues surrounding the disposal of used cooking oil, the availability of the population to donate this residual oil rather than discard it and its recycling for the production of new products. / Atualmente, a problemática geração de resíduos pelas atividades humanas é complexa e permanece desafiando as sociedades em geral, especialmente no contexto urbano. Para uma melhor destinação dos resíduos deve ser proposta uma política de recolhimento que além da destinação correta, é capaz de construir uma população sustentável do ponto de vista social e ambiental, através da redução dos resíduos produzidos e da reutilização e reciclagem de materiais como alternativa de renda. Existem alguns problemas provenientes do descarte inadequado de um resíduo altamente poluidor, os óleos e gorduras saturados, que apesar de em temperatura ambiente apresentar-se no estado líquido, ao entrar em contato com a água, se torna um resíduo sólido; por suas particularidades, quando descartado inadequadamente no meio ambiente, gera problemas de ordem econômica e ambiental, como a contaminação do solo e dos recursos hídricos e o entupimento de encanamentos e da rede de esgotamento sanitário, elevando os custos de manutenção das companhias de saneamento. Uma forma de reaproveitar o óleo de cozinha usado é a fabricação de novos produtos como biodiesel e sabão, evitando-se, assim, o descarte inadequado no meio ambiente e, consequentemente, a poluição ambiental e as nocividades à saúde humana. O universo amostral da pesquisa compreendeu os responsáveis por domicílios particulares no âmbito doméstico, escolhidas aleatoriamente, contemplando dois Bairros/Núcleos do Município de Itaara-RS, com um total de 50 pessoas entrevistados. Dessa forma, o estudo permitiu diagnosticar e entender o comportamento da população, relativo ao descarte de óleo de cozinha usado, com diferentes níveis sociais e sua disponibilidade em aderir as práticas mais sustentáveis do respectivo descarte. Além disso, analisou o potencial de recolhimento do óleo de cozinha usado e evidenciou a importância da coleta seletiva deste resíduo para mitigar os impactos ambientais por ele causado, quando descartado de forma inadequada. A pesquisa evidenciou tanto no bairro de menor renda, quanto no de maior renda, os entrevistados afirmaram que doariam o óleo para reciclagem por estarem preocupados com a preservação ambiental e evitar a poluição. Percebe-se que grande parte da população se preocupa com o meio ambiente, o que constitui uma manifestação favorável para o envolvimento no processo de coleta de óleo de cozinha usado, evitando seu descarte inadequado. Ainda, que o grau de disposição em doar o óleo usado, é positivo, os entrevistados de menor renda relataram que já aproveitam o resíduo na fabricação de sabão e na utilização da comida animal, o que constituiria menor disposição em colaborar com campanhas de doação de óleo usado, uma vez que destinavam o material ao uso próprio, por razões econômicas. No âmbito da presente pesquisa, onde a destinação de um resíduo poluente resultante da atividade humana é abordada, as atitudes e percepção ambiental da amostra, revelam o grau de conscientização e sensibilização sobre o seu papel na questão descarte do óleo de cozinha e o meio ambiente. Foi possível com a pesquisa a construção de um cenário de conhecimentos e expectativas por parte da população de Itaara frente às questões que envolvem o descarte do óleo de cozinha usado, a disponibilidade da população em doar esse óleo residual ao invés de descartá-lo e seu reaproveitamento para produção de novos produtos.

This study provides independent analysis of Residual Oil Zones (ROZs) in the Permian Basin from a regional perspective, focusing on the formation mechanism and present ROZ locations. Results demonstrate widespread potential for ROZs, defined here as thick volumes of reservoir rock containing near-residual saturations of predominantly immobile oil formed by natural imbibition and displacement of oil by dynamic buoyant or hydrodynamic forces. Previous work suggests hydrodynamic forces generated by regional tectonic uplift drove widespread oil remobilization and ROZ creation. To test the hypothesis, uplift and tilting are quantified and the resulting peak regional potentiometric gradient used as a physical constraint to compute and compare predicted ROZ thicknesses from hydrodynamics for several ROZ-bearing San Andres fields with known ROZ thicknesses. Late-Albian Edwards Group geologic contacts, which are interpreted to have been deposited near sea level prior to uplift, are used as a regional datum. Approximate elevations determined for the present datum show ~1800 m of differential uplift since Edwards deposition, with an average regional slope of ~0.128˚. This post-Edwards tilting increased the pre-existing regional structural gradient of the San Andres Formation to ~0.289˚. Using the calculated post-Edwards gradient results in to prediction of ROZ thicknesses from hydrodynamics that is consistent with measured ROZ thicknesses at several fields. When compared with countervailing buoyancy forces, hydrodynamics is calculated to be the more dominant driving force of oil movement for reservoirs with structural dips less than 1.5˚, which is the common dip for San Andres Formation platform deposits where ROZs have been identified. To predict the location of ROZs, ROZ-related oil field properties were identified and analyzed for over 2,800 Permian Basin reservoirs. A strong basin-wide correlation between API and crude sulfur content is consistent with the expected outcome of oil degradation driven by oil-water interaction, and supports the use of API and sulfur content as proxies for ROZ potential in the Permian Basin. Spatial analysis of sulfur data shows that the highest probability for ROZ existence exists in Leonardian through Guadalupian-age reservoirs, distributed primarily in shelf and platform areas of Permian structures. Combined, these results support the widespread potential for ROZs across the Permian Basin generated primarily by regional scale tilting and resultant hydrodynamic forces. / text

Data de aprova??o retirada da vers?o impressa do trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-08-30T18:13:36Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-08-30T18:51:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) / Made available in DSpace on 2017-08-30T18:51:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) gelson_cerqueira_oliveira_junior.pdf: 2578577 bytes, checksum: 83cb8ab9378ea856fed151a0f1c1992d (MD5) Previous issue date: 2015 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Neste trabalho s?lica gel foi preparada a partir de areia de constru??o e carbonato de s?dio, apresentando uma ?rea de superf?cie de 378,68 m2/g, e volume de poro de 1,59x10-2 cm3/g. A fim de preparar diferentes catalisadores a base do mesmo material uma al?quota foi previamente aquecida a 400? C e outra a 700? C, as quais foram denominadas S400 e S700 que ap?s tratamento com H2SO4, deram origem a dois diferentes catalisadores, chamados de C400 e C700. Os catalisadores apresentaram volume total dos mesoporos de 0,23 cm3/g (C400) e 0,20 cm3/g (C700) e ?rea superficial de 31,06 m2/g (C400) e 23,10 m2/g (C700). Pela primeira vez foi utilizado ?cido de Bronsted imobilizado em s?lica para a convers?o de OGR em biodiesel. Ambos C400 e C700 apresentaram alta atividade na convers?o do ?leo e gordura residuais altamente ?cidos (13,7 mg de KOH) e com teor de ?gua de 0,58%, a biodiesel (?steres met?licos de ?cido graxo) em aproximadamente 99,4 %. As rea??es foram repetidas 4 vezes antes do catalisador perder sua atividade catal?tica. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015. / In this work, silica gel was prepared from building sand and sodium carbonate, having a surface area of 378.68 m2/g and pore volume of 1,59x10-2 cm3/g. In order to prepare different catalysts the basis of the same material aliquot was preheated to 400? C and another at 700? C, which were referred to as S400 and S700 which upon treatment with H2SO4, gave rise to two different catalysts, called C400 and C700. The catalysts showed total volume of mesopores of 0.23 cm3/g (C400) and 0.20 cm3/g (C700) and surface area of 31.06 m2/g (C400) and 23.10 m2/g (C700). For the first time was used Bronsted acid immobilized on silica OGR for conversion into biodiesel. Both C400 and C700 showed high activity in the oil conversion and highly acidic waste fat (13.7 mg of KOH) and 0.58% water content, biodiesel (fatty acid methyl esters) by approximately 99.4% . Reactions were repeated four times before the catalyst to lose its catalytic activity.

Made available in DSpace on 2016-06-02T20:00:46Z (GMT). No. of bitstreams: 1 4668.pdf: 1300864 bytes, checksum: 47714fffabd94cd02784d632c827ebcd (MD5) Previous issue date: 2010-12-15 / The collection of solid waste generated in urban areas is a growing concern for governments, health professionals and environmentalists. Among these concerns is the disposal of vegetable oil used in homes, which requires a more appropriate final allocation. For this to be attained, it is necessary, in addition to public awareness, the planning for the collection, with pre-defined routes. This study simulates alternative systems to collect waste oil in some sectors of the city of São Carlos SP using a Geographic Information System GIS. Using this system, routes to be travelled by the collectors from door to door, are defined. The program used was the TransCAD, which is a GIS specific for transportation planning, transport professionals, enabling the development routes using algorithms that include a procedure for arc routing. For this study it was assumed that a collector truck would be parked at some defined points and the collection would be performed by collecting agents with carts following pre-defined routes. Several simulations were made, aiming at minimizing the length of the routes and the number of agents necessary for the task. The results obtained with the simulations demonstrated that it is possible to define sets of routes that minimize the cost and the manpower required for the door to door collection of discarded frying oil. / A coleta dos resíduos sólidos gerados no meio urbano é uma preocupação crescente para governantes, profissionais da saúde e ambientalistas. Dentre estas preocupações, encontra-se o descarte do óleo vegetal utilizado nas residências, que exige uma destinação final mais adequada. Para isto se faz necessário, além da conscientização da população, um planejamento de coleta, com rotas pré-definidas. Este estudo simula sistemas alternativos para coleta do óleo residual em alguns setores da cidade de São Carlos SP, usando um Sistema de Informações Geográficas SIG. Com o uso desse sistema são definidas rotas a serem percorridas pelos agentes coletores no processo de coleta seletiva para o óleo residual de fritura através do sistema porta-aporta. O programa utilizado foi o TransCAD, que é um SIG específico para planejamento de transportes, permitindo desenvolver rotas utilizando-se algoritmos que incluem um procedimento de roteirização em arco (Rotina Arc Routing). Para este estudo considerou-se que um caminhão coletor ficaria estacionado em pontos determinados e o serviço de coleta seria realizado por agentes coletores com carrinhos manuais seguindo percursos de coleta a pé. Foram feitas diversas simulações procurando minimizar os percursos de coleta e o número de agentes coletores necessários para a execução do serviço. Os resultados obtidos com as simulações demonstraram que é possível se obter conjuntos de rotas que minimizam o custo e a mão de obra necessária para a coleta porta a porto do óleo residual de fritura.

L'injection de tensioactifs est une méthode très appliquée dans le domaine de la récupération améliorée des hydrocarbures. Cependant, son efficacité repose sur la capacité de ces agents chimiques à mobiliser l'huile résiduelle en diminuant la tension interfaciale entre l'huile et l'eau. Des modèles à l'échelle du réservoir calculent l'efficacité de la récupération d'huile résiduelle par injection de solutions contenant des tensioactifs. Les mécanismes physiques pris en compte dans les modélisations font intervenir la physico-chimie du système roche-fluide et une courbe globale donnant la saturation résiduelle en huile en fonction du nombre capillaire (courbe de désaturation capillaire). Cette donnée est majeure dans le calcul de l'efficacité de récupération d'huile par injection de solutions de tensioactifs. En effet la mobilisation de l'huile résiduelle laissée en place après injection d'eau n'est possible qu'en augmentant considérablement le nombre capillaire. La prédiction de l'efficacité d'un procédé chimique de récupération passe par la compréhension, à l'échelle du pore, du processus de mobilisation des ganglions d'huile suivant la structure poreuse et le nombre capillaire. L'objet de cette thèse est de caractériser la récupération d'huile tertiaire en fonction du nombre capillaire dans diverses roches mouillables à l'eau. Ces courbes permettront de quantifier l'effet de la microstructure, les hétérogénéités du milieu poreux et diverses propriétés pétrophysiques sur la récupération d'huile. Cette thèse permettra aussi de caractériser les différents mécanismes d'action de tensioactifs sur la mobilisation d'huile résiduelle dans le milieu poreux. L'expérimentation par tomographie RX est utilisée. La tomographie RX permettra de caractériser les courbes de désaturation capillaire à l'échelle de Darcy et visualiser localement le déplacement d'huile résiduelle à travers les milieux poreux. Des essais d'écoulement diphasique sous micro-CT permettront d'observer in-situ et d'étudier les interfaces eau/huile et leurs évolutions en 3D au sein du milieu poreux en fonction du nombre capillaire. / Oil recovery by surfactant injection is related to oil-water interfacial tension and rock properties through the capillary number. In the modeling of oil recovery by surfactant injection, fluid flow physical mechanisms are represented through the capillary desaturation curve (CDC). This curve is central in the evaluation of oil recovery efficiency. In order to mobilize residual oil trapped after waterflooding by capillary forces, chemical EOR rely on increasing capillary number to extremely high values. The mechanisms governing oil release can be described at the pore scale where the balance of capillary and viscous forces is achieved. This description will help to predict the efficiency of surfactant based EOR processes by taking into account the porous geometry and topology, the physico-chemical properties of the fluids and the different phase interaction. The objective of this work is to characterize capillary desaturation curves for various strongly water-wet sandstones. These curves will be used to study the relationship between tertiary oil recovery and the pore structure, porous media heterogeneity and petrophysicals properties. The other aim of this work is to map the different mechanisms of oil recovery by surfactant injection. Experiments under X-Ray tomography are proposed. X-Ray tomography will be applied to characterize capillary desaturation curve at Darcy scale and to visualise the two phase flow saturation after injection. Pore scale experiments based on X-Ray micro-tomography imaging are performed to describe the different mechanisms of oil mobilization.

Heavy oil production depends on the understanding of mechanical and flow properties of unconsolidated or weakly consolidated sands under different loading paths and boundary conditions. Reconstituted bitumen-free Athabasca oil-sands samples were used to investigate the geomechanics of a steam injection process such as the Steam Assisted Gravity Drainage (SAGD). Four stress paths have been studied in this work: triaxial compression, radial extension, pore pressure increase and isotropic compression. Absolute permeability, end-point relative permeability to oil & water (kro and krw), initial water saturation and residual oil saturation were measured while the samples deformed. Triaxial compression is a stress path of increasing mean stress while radial extension and pore pressure increase lead to decreasing mean stress. Pore pressure increase experiments were carried out for three initial states: equal axial and confining stresses, axial stress greater than confining stress and confining stress greater than axial stress. Pore pressure was increased under four boundary conditions: 1) constant axial and confining stress; 2) constant axial stress and zero radial strain; 3) zero axial strain and constant confining stress; and 4) zero axial and radial strain. These experiments were designed to mimic geologic conditions where vertical stress was either S1 or S3, the lateral boundary conditions were either zero strain or constant stress, and the vertical boundary conditions were either zero strain or constant stress. Triaxial compression caused a decrease in permeability as the sample compacted, followed by appreciable permeability enhancement during sample dilation. Radial extension led to sample dilation, shear failure and permeability increase from the beginning. The krw and kro increased by 40% and 15% post-compaction respectively for the samples corresponding to lower depths during triaxial compression. For these samples, residual oil saturation decreased by as much as 40%. For radial extension, the permeability enhancement decreased with depth and ranged from 20% to 50% while the residual oil saturation decreased by up to 55%. For both stress paths, more shear-enhanced permeability was observed for samples tested at lower pressures, implying that permeability enhancement is higher for shallower sands. The pore pressure increase experiments showed an increase of only 0-10% in absolute permeability except when the effective stress became close to zero. This could possibly have occurred due to steady state flow not being reached during absolute permeability measurement. The krw curves generally increased as the pore pressure was increased from 0 psi. The increase ranged from 5% to 44% for the different boundary conditions and differential stresses. The kro curves also showed an increasing trend for most of the cases. The residual oil saturation decreased by 40-60% for samples corresponding to shallow depths while it increased by 0-10% for samples corresponding to greater depths. The reservoirs with high differential stress are more conducive to favorable changes in permeability and residual oil saturation. These results suggested that a decreasing mean stress path is more beneficial for production increase than an increasing mean stress path. The unconsolidated sands are over-consolidated because of previous ice loading which makes the sand matrix stiffer. In this work, it was found that over-consolidation, as expected, decreased the porosity and permeability (40-50%) and increased the Young’s and bulk moduli of the sand. The result is sand which failed at higher than expected stress during triaxial compression. Overall, results show that lab experiments support increased permeability due to steam injection operations in heavy oil, and more importantly, the observed reduction in residual oil saturation implies SAGD induced deformation should improve recovery factors. / text