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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.
41

Estudo da Correlação de Resultados da Destilação de Petróleo Pelas Normas ASTM D2892 e D5236 Com a Destilação Simulada pela ASTM D7169

QUEIROZ, L. O. S. 14 June 2017 (has links)
Made available in DSpace on 2018-08-01T21:36:54Z (GMT). No. of bitstreams: 1 tese_11042_Dissertação Lucas Queiroz - FINAL APROVADA.pdf: 801845 bytes, checksum: c02d945e52f528faf6319ad6dda19507 (MD5) Previous issue date: 2017-06-14 / A Destilação é um dos processos mais importantes na caracterização do petróleo pois o separa em diferentes frações. O conhecimento da distribuição dos pontos de ebulição dos componentes do petróleo e da proporção de seus cortes é essencial para o controle e logística desse processo durante o refino, além de garantir sua qualidade e possibilitar a valoração do óleo cru. Os métodos laboratoriais mais utilizados atualmente para este fim são as ASTM D2892 (destilação atmosférica: atinge temperatura máxima de 400 ºC) e ASTM D5236 (destilação a vácuo: utiliza pressões reduzidas para destilar o resíduo atmosférico para evitar o craqueamento das moléculas). A curva PEV (curva de pontos de ebulição verdadeiros - resultado laboratorial da destilação física) é obtida através da soma dos resultados das destilações atmosférica e a vácuo. Entretanto, esses processos demandam grandes quantidades de amostra (de 5 a 40 L) e tempo (3 a 4 dias). A Destilação Simulada por cromatografia gasosa (SIMDIS, do inglês Simulated Distillation) se apresenta como uma interessante solução para contornar esses problemas. A amostra é volatilizada e a separação de seus compostos ocorre no interior de uma coluna cromatográfica sob uma variação de temperatura controlada, produzindo um cromatograma e uma curva PEV. Neste trabalho, 98 amostras de petróleo nacionais e internacionais foram analisadas e seus dados foram correlacionados em diferentes etapas. Inicialmente, cada amostra foi analisada utilizando o método ASTM D7169 (SIMDIS) no laboratório de cromatografia do LabPetro na Universidade Federal do Espírito Santo (UFES). Essa etapa gerou 4 replicatas.para cada amostra, as quais foram submetidas a uma avaliação de similaridade para determinar qual apresentou o melhor resultado. Os dados da melhor replicata foram correlacionados com os obtidos no Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello (CENPES-Petrobras). A primeira comparação foi uma avaliação de similaridade realizada entre os resultados de SIMDIS dos dois laboratórios, realizada para 44 amostras (amostras cujos resultados de SIMDIS foram disponibilizados pelo CENPES). Em seguida, os dados de SIMDIS obtidos na UFES foram correlacionados com os da destilação convencional do CENPES-Petrobras. A correlação dos resultados se deu através da comparação dos valores de ponto de ebulição a cada 5% de recuperação em massa. A fim de obter esses valores para as duas técnicas, foi feito um ajuste polinomial de quinta ordem. Por fim, foi aplicado um teste de Viés para para avaliar a correlação dos dados. A avaliação final dos resultados evidenciou uma boa similaridade entre os resultados da destilação convencional e SIMDIS. A correlação para 13 petróleos (de um total de 15) obteve bons, não exibindo erros sistemáticos significativos.
42

Integrated processing for heavy crude oil

Lopez, Yadira January 2015 (has links)
Energy based on non-renewable resources such as gas, oil, coal and nuclear fission, even with their serious problems of pollution, contributes to 86% of the global energy consumption. Oil will remain the dominant transport fuel: about 87% of transport fuel in 2030 will still be petroleum-based. Discoveries of conventional sources of light easy-to-access crude oil are becoming less common and current oil production levels are struggling to match demand, it is necessary to develop new non-conventional sources of oil in order to supplement conventional oil supply, whose demand is increasing continuously. A possible clue to solve this situation could be to take advantage of the extensive reserves of heavy crude oils existing in different places around the world, which could be an excellent source of more valuable hydrocarbons. In this context, some facilities called upgraders are used to process theses heavy crude oils to both increase the hydrogen-carbon ratio and improve their quality, reducing their density and decreasing their viscosity, sulphur, nitrogen and metals. The main objective in this work is to study the heavy crude oil upgrading processes in order to identify new operation schemes which explore different opportunities of integration between the upgraders and other processes or new schemes for upgraders that can sustain on its own through the production of a wide range of products. Each design alternative has been modelled with state-of-the-art commercial software packages. The crude oil dilution process was evaluated using naphtha and a light crude oil as diluents. Sensitivity analyses were done with the purpose of selecting the type and flow rate of diluent. Once the best diluent was selected, the integration of an upgrader to a refinery was studied. Heavy ends from both the upgrader and the refinery were taken as feedstocks to an integrated gasification combined cycle (IGCC). The best operation schemes for IGCC, in order to achieve the requirements of power and hydrogen for the upgrader and the refinery was determined. Different schemes for heavy crude oil processing to produce transportation fuel instead of syncrude were proposed, too. Finally, economic evaluation of all the schemes was performed to find the best solution for heavy crude oils. The best results for the dilution process of heavy crude oils were obtained when naphtha was used as diluent. The configuration proposed for the upgrader allows producing a synthetic crude oil with 35.5 °API. The integration of the upgrader to a refinery allows the treatment of the heavy streams of the refinery and transforms them into products of higher qualities. The integration of the IGCC to the upgrader and the refinery permits a complete elimination of the heavy residues produced in these units and produces hydrogen and power to be used in the site or to export. Economic evaluation shows that all the proposed processing schemes studied are economically attractive. The proposed processing schemes chosen include the integration between upgrader refinery and IGCC unit with CCS.
43

Formulation of Zeolite-based Catalysts for Hydrocarbon Processing

Shoinkhorova, Tuiana 02 1900 (has links)
With demand for gasoline and diesel expected to decline in the near future, crude-tochemicals technologies have the potential to become the most important processes in the petrochemical industry. This trend has triggered intense research to maximize the production of light olefins and aromatics at the expense of fuels, which calls for disruptive processes able to transform crude to chemicals in an efficient and environmentally friendly way. Simultaneously, the production of high-demand chemical commodities such as olefins, aromatics and gasoline from alternative feedstocks such as methanol has been central to research in both academia and industry. In both conversions, catalyst composition and formulation play a key role. In principle, shaping and optimal compositional formulation are major challenges in the successful industrial application of heterogeneous catalysts. Herein, we evaluate the application of the spray-drying shaping technique to manufacture spherical zeolite-based catalysts and their applicability in the direct crude-to-chemicals and the methanol-to-hydrocarbons processes. A thorough study of the effect of formulated fluid catalytic cracking catalyst composition on the one-step cracking of Arabian light crude oil was studied in the present thesis. Our results demonstrate that over a 35wt.% yield to light olefins can be achieved on spray-dried catalysts containing 1:1 mixtures of ZSM-5 and FAU zeolites. On the other hand, the nature of the selected clay, one of the key components in formulated catalysts, has a significant influence in modifying the final acidity of the composite, which, when applied in methanol to hydrocarbons, results in the propagation of either the alkene or arene cycles. The present PhD thesis also has been dedicated to the study of optimal conditions for the highly selective and stable production of aromatics during methanol to aromatics at high pressure. High selectivity to aromatics (~50%) can be achieved on a commercial high silica ZSM-5 at 400° and 30 bar total pressure. The high partial pressure of primary olefins and the promoted methanol-induced hydrogen transfer pathway result in an exponential increase in aromatization, while the high partial pressure of steam generated via dehydration of methanol leads to in situ coke removal and, therefore, to a slower deactivation of the zeolite.
44

Acute Toxicity of Crude Oil Exposures to Early Life Stage Teleosts: Contribution of Impaired Renal Function and Select Environmental Factors

Bonatesta, Fabrizio 08 1900 (has links)
Oil spills are well-known adverse anthropogenic events, as they can induce severe impacts on the environment and negative economic consequences. Still, much remains to be learned regarding the effects of crude oil exposure to aquatic organisms. The objectives of this dissertation were to fill some of those knowledge gaps by examining the effects of Deepwater Horizon (DWH) crude oil exposure on teleost kidney development and function. To this end, I analyzed how these effects translate into potential osmoregulatory impairments and investigated the interactive effects of ubiquitous natural factors, such as dissolved organic carbon (DOC) and ultraviolet (UV) light, on acute crude oil toxicity. Results demonstrated that acute early life stage (ELS) crude oil exposure induces developmental defects to the primordial kidney in teleost fish (i.e., the pronephros) as evident by alterations in: (1) transcriptional responses of key genes involved in pronephros development and function and (2) alterations in pronephros morphology. Crude oil-exposed zebrafish (Danio rerio) larvae presented defective pronephric function characterized by reduced renal clearance capacity and altered filtration selectivity, factors that likely contributed to the formation of edema. Latent osmoregulatory implications of crude oil exposure during ELS were observed in red drum (Sciaenops ocellatus) larvae, which manifested reduced survival in hypoosmotic waters, likely due to defective pronephros development and function. Finally, DOC-UV co-exposure slightly reduced acute crude oil photo-enhanced toxicity in red drum larvae. This dissertation provided novel information regarding crude oil toxicity that can be incorporated into environmental risk assessment and management for future oil spills.
45

The effects of crude oil on terrestrial vegetation

Brown, Si January 1974 (has links)
Note:
46

Production of Eicosapentaenoic acid from biodiesel derived crude glycerol using fungal culture

Athalye, Sneha Kishor 29 September 2008 (has links)
Omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA, C20:5, n-3) and docosahexaenoic acid (DHA, C22:6, n-3), have many medically established benefits against cardiovascular diseases, cancers, schizophrenia, and Alzheimer's. Currently, fish oil is the main source of omega-3 fatty acids, but there are many problems associated with it such as undesirable taste and odor, and heavy metal contamination. As a result, it is necessary to seek alternative production sources based on various microorganisms. In this thesis we have developed a novel microfungal culture process to produce EPA from the crude glycerol byproduct generated in biodiesel industry. This process provides both an alternative source of omega-3 fatty acids and a benefit to the biodiesel industry. Indeed, as oil prices reach historical highs, biodiesel has attracted increasing interest throughout the United States. The disposal of the crude glycerol byproduct has been a challenge faced by the biodiesel producers. Crude glycerol presents a cheap carbon source for growth of many microorganisms. In this thesis, we tested the feasibility of using crude glycerol for producing eicosapentaenoic acid (EPA, 20:5, n-3) by one algal species, Phaeodactylum tricornutum and two fungal species, Mortierella alpina and Pythium irregulare. We observed that the algal growth is inhibited in the crude glycerol while the fungi can grow very well in crude glycerol-containing medium. The fungus M. alpina produced significant amount of ARA but negligible amount of EPA. P. irregulare produced significant amount of biomass as well as a relatively high level of EPA. The maximum dry biomass for the P. irregulare culture was 2.9 g/L with an EPA productivity of 7.99 mg/L-day. Based on these results, we concluded that P. irregulare was a promising candidate for EPA production from biodiesel derived crude glycerol. Further optimization work showed that P. irregulare grown 30 g/L crude glycerol and 10g/L yeast extract results in the highest level of EPA production. A temperature of 20o C is optimal for high fungal biomass and EPA levels. Addition of vegetable oil (at 1%) enhanced the EPA production and almost doubled the amount of biomass reached. Soap inhibits growth as well as EPA production severely even in small amounts. Methanol completely inhibits growth. The final optimized growth conditions for the fungus P.irregulare were a medium with 30g/L of crude glycerol, 10 g/L of yeast extract at a pH of 6 with 1% supplementation of oil, at a temperature of 20o C for a period of 7 days.Thus we have established that the fungus P.irregulare can be used successfully to produce high mounts of EPA from crude glycerol. / Master of Science
47

Use of Biodiesel-Derived Crude Glycerol for the Production of Omega-3 Polyunsaturated Fatty Acids by the Microalga Schizochytrium limacinum

Pyle, Denver 07 May 2008 (has links)
Crude glycerol is the major byproduct of the biodiesel industry. In general, for every 100 pounds of biodiesel produced, approximately 10 pounds of crude glycerol are created. Because this glycerol is expensive to purify for use in food, pharmaceutical, or cosmetics industries, biodiesel producers must seek alternative methods for its disposal. Using crude glycerol as a carbon source for fermentation is a promising alternative use for this waste material. In this project, we propose to use crude glycerol in the fermentation of the microalga Schizochytrium limacinum, which is a prolific producer of docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid with proven beneficial effects on treating human diseases such as cardiovascular diseases, cancers, and Alzheimer's. The first part of this study provided "proof-of-concept" that Schizochytrium limacinum was capable of utilizing crude glycerol while producing DHA. The results show that pretreated crude glycerol was a viable carbon source for algal growth and DHA production, with 75 g/L to 100 g/L of glycerol being the optimum concentration range. In addition to glycerol concentration, temperature, trace metal levels, ammonium acetate concentration, and NH4Cl concentration also had significant effects (P < 0.1) on algal DHA production. Optimizing these factors using response surface methodology led to a DHA yield of 4.91 g/L and a DHA productivity of 0.82 g/L-day. The second part of this study investigated the effects of impurities within the glycerol on DHA production and algal biomass composition, with a goal of ensuring that the algal biomass produced from crude glycerol can be safely utilized as an ingredient in omega-3 fortified foods or animal feed additives. Crude glycerol samples obtained from different biodiesel producers were tested. All the samples contained methanol, soaps, and various elements including calcium, phosphorus, potassium, silicon, sodium, and zinc. Both methanol and soaps in the glycerol negatively influence algal DHA production. The two impurities can be removed from the culture medium by evaporation through autoclaving (for methanol) or by precipitation through pH adjustment (for soap). The results showed that the crude glycerol-derived algal biomass contained 45-50% lipid, 14-20% protein, and 25% carbohydrate, with 8-13% ash content. Palmitic acid (C16:0) and DHA (C22:6) were the two major fatty acids in the algal lipid. ICP analysis showed that that boron, calcium, copper, iron, magnesium, phosphorus, potassium, silicon, sodium, and sulfur were present in the algal biomass, but no heavy metals (such as mercury) were detected. The crude glycerol-derived algal biomass had a high level of DHA and a nutritional profile similar to glucose-derived commercial algal biomass, suggesting a great potential for using crude-glycerol derived algae in omega-3 fortified food or feed. Overall, this study shows that crude glycerol can be used as a safe and effective substrate for algal culture to produce high levels of omega-3 fatty acids. With the rapid expansion of the biodiesel industry, there is an urgent need to develop new markets for large quantities of crude glycerol. This research provides an exciting opportunity to utilize a large quantity of this low grade glycerol. / Master of Science
48

Esterificação seletiva para a separação de esterois, acidos resinicos e acidos graxos do residuo oleoso de madeira (Tall oil) / Process for obtaing fatty acid allkyl esters, rosin acids and sterols from crude tall oil

Sales, Henrique Jorge Sousa 26 February 2007 (has links)
Orientador: Ulf F. Schuchardt / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-09T20:28:05Z (GMT). No. of bitstreams: 1 Sales_HenriqueJorgeSousa_D.pdf: 2216336 bytes, checksum: 8961d924bfe31e720b51411a6194bd10 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho, estudamos a esterificação seletiva química e enzimática para a separação dos esteróis, ácidos resínicos e ácidos graxos do resíduo oleoso de madeira, o Crude Tall Oil (CTO). A reação de esterificação enzimática (Candida antartica, lípase do tipo B) foi otimizada utilizando-se um planejamento fatorial 2. Os fatores estudados foram o tempo de reação (h), a temperatura da reação (°C), o teor de catalisador (%), o teor de metanol (%) e o teor de água (%). Com o aumento da temperatura de 24 para 60 °C observamos uma redução média na taxa de conversão de 26,6 %. O aumento da percentagem de metanol de 5 para 15 % também apresentou um efeito negativo na taxa de conversão de 13,1 %; isso indica uma inativação térmica (com a aumento da temperatura) e uma inativação do sítio ativo da enzima pelo metanol. O aumento da porcentagem de água de 0 para 15 % e do tempo de reação de 6 para 24 h apresentou um aumento de 31,2 e de 8,1 %, respectivamente, para a conversão. A interação entre a água e o metanol apresentou um efeito positivo de 22,5 % sobre a conversão, sendo que a melhor condição foi a de efetuar a reação à baixa temperatura (24 °C) com altos teores de água (10-15%) e metanol (10-15%). A adição do metanol em duas etapas também favoreceu a reação, devido ao efeito de desativação que o metanol tem sobre a enzima. O processo foi implementado em produção, onde 13,7 tons de CTO foram esterificadas em um tanque de 25 m e, após 166 h de reação, o índice de acidez caiu de 153,5 para 57,4 mgKOH/g. Através das análises do teor de ácidos resínicos livres, constatamos a total esterificação dos ácidos graxos presentes no CTO. O catalisador enzimático foi adsorvido em polipropileno e foram produzidos dois catalisadores heterogêneos com 0,2 g/g e 0,5 g/g; a relação 0,2 g/g foi a que apresentou a melhor relação custo-benefício para as reações em batelada. O catalisador heterogêneo foi empacotado em uma coluna, e essa foi utilizada para os experimentos de esterificação contínua. O catalisador se mostrou estável por mais de 50 dias. Comparando a performance do processo enzimático x processo químico, o catalisador enzimático apresentou melhor produtividade e seletividade. O resíduo obtido pelo fracionamento em um evaporador thin film apresentou um alto teor de esteróis livres (1,83%) e esteróis esterificados (22,31%). A fração leve do CTO esterificado foi fracionada em uma coluna de destilação piloto. Com este novo processo, obtivemos ésteres metílicos com alto grau de pureza e isento de contaminação por ácidos resínicos. No processo de purificação por destilação, obtivemos ácidos resínicos com 72,3% de pureza. O processo de esterificação seletiva e de fracionamento do CTO foi patenteado pela Cognis do Brasil. / Abstract: A process for obtaining fatty acid alkyl esters, rosin acids an sterols from Crude Tall Oil was developed. As first process step, a chemical or enzymatic esterification has been proposed. It has been shown that the enzymatic esterification of crude tall oil is technically and economically feasible. A 2 experimental design, to optimize the enzymatic process, was done. The factors studied were; reaction time (h), temperature (°C), catalyst (%), methanol (%) and water (%). Increasing the temperature to 60 °C, the conversion decreased 26.6%. The use of high amount of methanol resulted on a conversion of 13.1%. The increase of reaction time and amount of water improved the conversion in 8.1 % and 31.2 %. The best conditions found were reaction time (24 h), temperature (25 °C), water (10-15 %) and methanol (10-15 %). Dosage of methanol must be used because with higher amount of alcohol occurs deactivation of the enzyme. The laboratorial scale experiments were successfully, transferred to a 25 m pumped reactor in the industrial plant. An acid value reduction from 153.5 to 57.4 in 166 hrs could be achieved. Using an immobilized biocatalyst, 0.2 g/g and 0.5 g/g, experiments in a stirred reactor have been performed. The best results were obtained with the 0.2 g/g catalyst system. The biocatalyst was used for successive batches. A continuous process in a column was successfully performed in laboratorial scale. The column was stable for more then 50 days in continuous operation. We compared the performance of enzymatic and chemical esterification. The enzymatic process has better productivity than the chemical process. The separation of the methyl esters and rosin acids from the sterol borates by thin film distillation produced a pitch with (1.83 %) of free sterols and (22.31 %) of total sterols. The separation of the methyl esters from the rosinic acids by distillation produced a high purity methyl ester free of resinic acids and a resinic acid with 72.3 % of purity. The process consists of five steps: 1- Enzymatic and chemical esterification of the tall oil fatty acids with methanol to convert the TOFA in methyl esters; 2- Stripping of water/methanol; 3- Esterification of the free sterols with boric acid. 4- Separation of the methyl esters and rosinic acids from the sterol borates by distillation and 5- Separation of the methyl esters from the rosinic acids by distillation. The process was patented by Cognis Brasil. / Doutorado / Quimica Organica / Doutor em Ciências
49

Perspektívy vývoja na trhu s ropou / Perpectives of crude oil market developement

Vosková, Michala January 2008 (has links)
Crude oil is an important commodity of world trade and it has become an essential part of everyday life. It is a necessary condition of economic growth, which in the current situation of economic boom of China, India and other developing countries entails an economically, ecologically, socially and geopolitically unsustainable problem. The turbulent sequence of past events on the crude oil market only foreshadows the future development that is going to occure after achieving the crude oil production peak. The following irreversible changes will be more revolutionary than evolutional. The era of cheap oil will parish and the 21st century is going to be distinguished by fights for energy and resources. This is one of the reasons why many renowned institutions and organisations are concerned with these questions, trying to predict future scenarios and find feasible solutions. The world needs secure, renewable and environmentally friendly energy sources, however crude oil is unfortunately none of them. Radical transition from crude oil economy to a clean alternative one, that is probably the most suitable solution to current situation, will require engagement of governments, organisations and individuals as well. It is an inevitable step of preserving the world for humanity and the coming generations. Crude oil market perspectives are quite well foreseeable for the coming decades, questionable remains only the proper solution of the rising problems and action of taking the correct steps in the right direction.
50

Odhad cenové elasticity poptávky po ropě / Estimation of price elasticity of crude oil demand

Jonák, Ondřej January 2009 (has links)
Objective of this diploma thesis is estimation of price elasticity of crude oil demand. In order to calculation of such elasticity crude oil demand is estimated with econometrical methods. The choice of suitable model, which sufficiently and accurately models crude oil demand, is initial position of analysis. Consequently, crude oil demand is estimated from market data obtainable from public sources. This estimated model is verified from economic, statistic and econometric point of view. Consequently, price elasticity of crude oil demand is calculated from such model.

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