Made available in DSpace on 2014-12-17T14:57:46Z (GMT). No. of bitstreams: 1 JohnENV.pdf: 2614116 bytes, checksum: 0c3230c680d60ac346167f3aa79669e3 (MD5) Previous issue date: 2004-06-04 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The investigation of viability to use containers for Natural Gas Vehicle (NGV) storage, with different geometries of commercial standards, come from necessity to join the ambient, financial and technological benefits offered by the gas combustion, to the convenience of not modify the original proposal of the automobile. The use of these current cylindrical models for storage in the converted vehicles is justified by the excellent behavior that this geometry presents about the imposed tensions for the high pressure that the related reservoirs are submitted. However, recent research directed toward application of adsorbent materials in the natural gas reservoirs had proven a substantial redusction of pressure and, consequently, a relief of the tensions in the reservoirs. However, this study considers alternative geometries for NGV reservoirs, searching the minimization of dimensions and weight, remaining capacity to resist the tensions imposed by the new pressure situation. The proposed reservoirs parameters are calculated through a mathematical study of the internal pressure according to Brazilian standards (NBR) for pressure vessels. Finally simulations of the new geometries behavior are carried through using a commercially avaible Finite Element Method (FEM) software package ALGOR? to verify of the reservoirs efficincy under the gas pressure load / A investiga??o da viabilidade de se utilizar recipientes para armazenamento de g?s natural veicular (GNV), com geometrias diferentes dos padr?es comerciais, parte da necessidade de se aliar os benef?cios ambientais, financeiros e tecnol?gicos oferecidos pela combust?o do g?s, ? conveni?ncia de n?o se alterar a proposta original do autom?vel. O uso dos atuais modelos cil?ndricos para estocagem nos ve?culos convertidos justifica-se pelo excelente comportamento que essa geometria apresenta diante das tens?es provocadas pela alta press?o a que os referidos reservat?rios est?o submetidos. Entretanto, recentes pesquisas, voltadas para aplica??o de materiais adsorventes nos reservat?rios de g?s natural, comprovaram uma substancial redu??o de press?o e, consequentemente, um al?vio das tens?es nos reservat?rios. Diante desse contexto, este estudo prop?e geometrias alternativas para os reservat?rios de GNV buscando a minimiza??o das dimens?es e do peso, mantendo-se, por?m, a capacidade de resistir ?s tens?es impostas pela nova situa??o de press?o. Todos os par?metros geom?tricos dos reservat?rios propostos s?o calculados realizando o estudo matem?tico das tens?es internas de trabalho tomando como base ? norma brasileira (NBR). Por ?ltimo s?o realizadas simula??es do comportamento das novas geometrias fazendo uso do software comercial ALGOR? o qual se baseia no M?todo dos Elementos Finitos (MEF), para realizar a comprova??o da efici?ncia dos reservat?rios sob a press?o imposta pelo g?s

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente trabalho é apresentar um estudo sobre o equilíbrio de fases sólido-líquido-vapor para hidratos de metano. A análise do equilíbrio trifásico sólido-líquido-vapor tem encontrado diversas aplicações para sistemas hidrocarboneto-água, uma vez que permite, por exemplo, a determinação da região de estabilidade de hidratos de metano e hidratos de gás natural. Inicialmente foi feita uma pesquisa sobre o estado da arte no que diz respeito ao comportamento termodinâmico e equilíbrio de fases de hidratos. Foram implementados os modelos apresentados por Ballard (2002) e Zhang et al. (2005). A proposta de Zhang et al. (2005) é aplicável para equilíbrios de fases a temperaturas abaixo de 300 K. Sua abordagem combinou a teoria de van der Waals e Platteeuw para a fase hidrato com a equação do estado de Peng-Robinson (1976) modificada por Stryjek e Vera (1986) para ambas as fases fluidas (fase vapor e fase aquosa). A abordagem de Ballard (2000) considerou a distorção do hidrato do seu estado padrão, o que fornece uma exata composição do hidrato e melhora a previsão da formação dos hidratos a altas pressões. Ao esclarecer a mudança de volume no hidrato, o raio da gaiola do hidrato é uma função do seu volume. Com isso, Ballard propôs uma nova abordagem considerando tal variação de volume e gerou um equilíbrio de fases em uma rotina de flash multifásico através da minimização da energia livre de Gibbs. Assim, o presente trabalho apresenta as abordagens de Zhang et al. (2005) e Ballard (2002) para o comportamento termodinâmico de hidratos e faz uma análise e comparação entre eles. Para resolver o problema do flash computacionalmente, foi utilizada a ferramenta lsqnonlin (built-in do software MATLAB). O lsqnonlin é um algoritmo baseado no método de Levenberg-Marquadt. / The objective of the present work is to present a study of solid-vapor-liquid three-phase equilibrium for methane hydrates. The analysis of three-phase equilibrium has several applications for water-hydrocarbon systems, since it permits, for example, determination of stability region for methane hydrates and natural gas hydrates. We have started seeking in literature about the state-of-art for thermodynamic behaviour and phase equilibrium for hydrates. And then the models proposed by Ballard (2002) and Zhang et al. (2005) were implemented. Zhang et al. (2005) have proposed a phase equilibrium for single-guest gas hydrates at temperatures below 300 K. Their approach has combined the van der WaalsPlatteeuw theory for the hydrate phase and the PengRobinson equation of state for both fluid phases (vapor and aqueous phase) (1976) modified by Stryjek and Vera (1986). Ballards (2000) approach has allowed the hydrate distortion from its standard state and has gave a more accurate composition of the hydrate and has improved hydrate formation predictions at high pressures. As a direct result of accounting for a changing hydrate volume, the cage radii were functions of the hydrate volume. Thus, Ballard have proposed the hydrate phase equilibrium by Gibbs energy minimization in a multi-phase flash routine. Thus, this work presents the Zhang et al. (2005) and Ballards (2002) approaches for hydrate thermodynamic behavior and makes an analysis and comparison of them. To compute the flash problem, we use the tool lsqnonlin (built-in of MATLAB software). The algorithm lsqnonlin is based on the Levenberg-Marquadt method.

The resource curse is a defining feature of the African content. Despite vast resource wealth, Africa remains the poorest and most underdeveloped continent in the world. The aim of this study is to conduct a comparative analysis of the primary laws regulating of oil and gas exploration and product activities in Angola, Nigeria and South Africa in order to determine their effectiveness in protecting the continent's depleting petroleum resources. Different regulatory models apply to Angola, following the Norwegian carried-interest model, Nigeria, where a British discretionary model has been retained, an a South africa, where a unique model has been developed. The comparison is conducted by analysing and comparing these different regulatory systems in terms of legal frameworks; the legal nature of the regulatory systems; ownership of the oil and gas resources; legal nature of licenses; organisational or institutional structures; fiscal systems; local communities benefits from these proceeds of oil and gas resources; local content; state/government participation arrangements; and environmental challenges. The study evaluates the effectiveness of these regimes by examining the extent to which they recognise and enforce state ownership of he oil and gas resourcs in situ; recognise and enforce the doctrine of Permanent Sovereignty over Natural Resources (PSNR); protect the environment; how they provide for institutional capacities for the management of resources; and the protection of local communities from exploitation and abuse by recognising their rights to benefit from revenues derived from these resources. An overall assessment of the three systems reveals that there is no ideal model for oil and gas regulation in Africa. The Norwegian model might well be considered an ideal model if it was applied with care and correctly in Angola. The study hopes to gain practical importance for the proper regulationof the oil and gas industries' upstream activities in Africa and assist governments of the selected jurisdictions in their policy revisions, as some recommendations are made. / Public, Constitutional and International Law / LL. D.

Il dissolvimento dell'Unione Sovietica, alla fine del 1991, ha avuto un impatto di straordinaria rilevanza sull'Asia Centrale. Se il controllo di Mosca sull'area portò alla formazione di entità statuali con confini artificiali e caratterizzate dalla presenza al loro interno di un intricatissimo melting pot etnico, il crollo dell'Urss ha fatto sorgere un inedito scenario geopolitico. Il vuoto di potere registrato nel centro asiatico, infatti, ha generato una serrata competizione diplomatica tra i principali attori del sistema internazionale, ansiosi di accrescere la propria influenza sulla regione. Ciò sulla base dei principali fattori della sua rilevanza strategica, primo fra tutti quello energetico. Prendendo le mosse da tali considerazioni, il progetto di ricerca – utilizzando un approccio storico-politico – mira ad analizzare la geopolitica dell'energia relativamente al Turkmenistan, paese che dispone delle quarte riserve mondiali di gas naturale. Sulla base, da un lato, delle peculiari caratteristiche di tale risorsa e, dall'altro, dell'impatto del suo possesso sulla sfera politica interna e la proiezione internazionale della Repubblica centro asiatica, ci si propone di stabilire se quest'ultima abbia la possibilità di accrescere in futuro il proprio ruolo geopolitico, diventando un attore al centro delle dinamiche strategiche regionali e globali. / The crumbling of the Soviet Union at the end of 1991 has represented a decisive moment for Central Asia. Moscow's control over the area favoured the formation of state actors characterized by artificial frontiers and an extraordinary ethnic mix. On the other hand, the soviet dissolution has led to a new geopolitical situation. The lack of power experimented in the region has generated an international diplomatic race, with the main state actors eager to increase their influence over Central Asia. This mainly due to the strategic relevance of the area, especially related to the energy dimension. By starting from these assumptions, the research project aims to analyze – by adopting an historical-political approach – the geopolitics of energy with reference to Turkmenistan, a country that has at its disposal the fourth biggest reserves of natural gas globally. On the basis of the specific properties of this raw material on the one hand, and of the impact of its possession on the turkmen political sphere, on the other, the issue is defined. The goal is to establish whether Turkmenistan has the chance to increase its future geopolitical role, becoming an actor at the heart of regional and global strategic dynamics.

The playing field upon which actors, both state and non-state, develop strategies to secure existing supplies of oil and seek access to new ones is as systemically, politically and strategically complex is as it is geographically vast. In considering this activity, the terminology used by pundits and journalists to describe the significance of issues such as oil demand, the complexities of access to petroleum and concerns over security threats to supplies of oil is familiar. Juxtapositions such as the ‘geopolitics of oil', ‘energy geopolitics', the ‘geopolitics of resource wars' and the ‘geopolitics of oil and gas' are all familiar. But what do they mean when they use ‘geopolitics' in this context? Thus, by extension, can petroleum geopolitics - a hybrid conceptual construction used in this thesis - be disassembled into its component parts, analysed and systematically understood. This is the aim of this thesis. This thesis contends that the very nature of oil and gas reserves, the processes of exploration and production, and the means that govern and characterise the transportation of petroleum overland and by sea is inherently geopolitical - that some core features of geopolitical theory and key geopolitical concepts are pivotal in determining the ontology and process of the international oil business. Indeed, so central has oil been to the advancement of industrial capacity, technology, warfare, transportation and economic prosperity of states since the 20th century, it could be argued that petroleum is the single largest determinant of the geopolitics that characterises the modern international system. In order to address the interrelationship and correlations between core aspects of the petroleum industry and causal geopolitical phenomena, I begin by advancing a framework of analysis that systematically binds key geopolitical features and concepts – specifically: Spatial Phenomena; Environmental Ontology; Territorial Access; Geopolitical Features; State and Non-state Concepts; and, Strategic Resources and Geopolitics - with examples of empirical findings revealed in subsequent chapters in the thesis. Fundamentally, this process works to assess causality and correlations between geopolitical phenomena such as space and distance, sovereignty, territory, boundaries, chokepoints, resource nationalism, transnationalism, resource security and conflict, and the features and processes inherent in petroleum reserves and the exploration, production and transportation of oil and gas. The framework is followed with a sequential analysis of the three empirical foci of the project: the ontology of oil and natural gas reserves; the planning and processes of exploration and production; and, the processes of the conveyance petroleum. I have concentrated my research to activities within Eurasia, which comprises the traditional continents of Europe and Asia, and the Indo-Pacific maritime realm, which extends eastwards from the Red Sea to the western Pacific Rim. After systematically assessing the empirical findings and examining key areas of geopolitical theory, I conclude that there is an identifiable and logical correlation between geopolitical phenomena, petroleum reserves, and the means to produce and distribute oil and gas between source and market.

Due to the vast fossil fuel wealth, the country of Saudi Arabia is experiencing a dramatic growth in both population and GDP. Therefore there is a growing demand for water and energy to meet these needs. All of the electricity that is generated is sourced from crude oil and natural gas. All natural gas production is used domestically and there are no net imports or exports. Due to many constrains on the natural gas supply, there is a slow shift in the generation mix going towards crude oil based power generation. This study assessed the viability of utility scale solar integration into the Saudi Arabian electric mix to potentially relieve some demand pressure for natural gas consumption as well as reduce green house gas emissions. Parabolic trough concentrated solar power technology was chosen as the primary technology for utility scale integration. A total of five scenarios were calculated. The scenarios include the following, base case, 5%, 10%, 15%, 20% solar integration in terms of installed capacity. Two sets of net present values were calculated. The net present values of each scenario were calculated. A second set of net present values was calculated with a projected increase in electricity prices. The natural gas and crude oil offset from the four solar integration scenarios were calculated using the base case forecasted natural gas and crude oil consumption from power generation. As expected, natural gas and crude oil consumption decreased when there was an increase in solar integration. The expected carbon dioxide offsets were calculated for each scenario. There was a decrease in carbon dioxide emission as solar integration was increased. Finally, all of these analyses were used as criteria for a decision analysis using the analytical hierarchy process. Depending on the decision maker’s importance on the determined criteria, solar integration in the Kingdom of Saudi Arabia is achievable. / text

The Texas ERCOT market is one of the most open, deregulated electricity markets in the world. This open market brought electricity costs down for Texas residents and businesses, creating a much more competitive economic climate. However, these low prices currently generate insufficient revenue for generators to finance construction of new or replacement generation assets. In the instance of combined cycle advanced natural gas, the Independent Market Monitor 2012 annual report estimated that a plant needed to generate 2.5 times as much as revenue it did in 2012 to incent new generation. This author argues that while the gap is still significant, the continuous changes to the ERCOT market since its inception make an historical examination like that used by the IMM less accurate. New market rules such as price caps or changes in fuel markets through new technologies like hydraulic fracturing create a very different valuation gap than a model based on historical activity alone. This analysis attempts to get a more accurate approximation of the gap through the use of publicly traded futures contracts for natural gas and electricity. Electricity futures reflect market expectations of revenue based on current and future market rules. Gas futures reflect price expectations in light of market changes like fracturing, potential LNG exports, and other changes. Financial positions can be maintained in both markets to give a fixed rate of return. Using this method, one can create a very conservative valuation model that still more accurately reflects market sentiment. This thesis starts with a brief history of ERCOT deregulation from the early 2000s to present in order to clarify for the reader the changes that have taken place in the market. It then demonstrates the futures-valuation model using an advanced combined cycle power plant as an example. / text

No description available.

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation applications that impact the environment and the quality of methane and hydrogen fuels. The work described herein describes post-synthesis modification of Nanoporous Organic Frameworks (NPOFs) and its impact on gas storage and selective CO2 capture. The synthesis of NPOF-4 was accomplished via a catalysed cyclotrimerization reaction of 1,3,5,7-tetrakis(4-acetylphenyl)adamantane in Ethanol/Xylenes mixture using SiCl4 as a catalyst. NPOF-4 is microporous and has high surface area (SABET = 1249 m2 g-1). Post-synthesis modification of NPOF-4 by nitration afforded (NPOF-4-NO2) and subsequent reduction resulted in an amine-functionalized framework (NPOF-4-NH2) that exhibits improved gas storage capacities and high CO2/N2 (139) and CO2/CH4 (15) selectivities compared to NPOF-4 under ambient conditions. These results demonstrate the impact of nitro- and amine- pore decoration on the function of porous organic materials in gas storage and separation application.

L'optimisation de l'exploitation d'un réseau de transport de gaz naturel (RTGN) est typiquement un problème d'optimisation multiobjectif, faisant intervenir notamment la minimisation de la consommation énergétique dans les stations de compression, la maximisation du rendement, etc. Cependant, très peu de travaux concernant l'optimisation multiobjectif des réseaux de gazoducs sont présentés dans la littérature. Ainsi, ce travail vise à fournir un cadre général de formulation et de résolution de problèmes d'optimisation multiobjectif liés aux RTGN. Dans la première partie de l'étude, le modèle du RTGN est présenté. Ensuite, diverses techniques d'optimisation multiobjectif appartenant aux deux grandes classes de méthodes par scalarisation, d'une part, et de procédures évolutionnaires, d'autre part, communément utilisées dans de nombreux domaines de l'ingénierie, sont détaillées. Sur la base d'une étude comparative menée sur deux exemples mathématiques et cinq problèmes de génie des procédés (incluant en particulier un RTGN), un algorithme génétique basé sur une variante de NSGA-II, qui surpasse les méthodes de scalarisation, de somme pondérée et d'ε-Contrainte, a été retenu pour résoudre un problème d'optimisation tricritère d'un RTGN. Tout d'abord un problème monocritère relatif à la minimisation de la consommation de fuel dans les stations de compression est résolu. Ensuite un problème bicritère, où la consommation de fuel doit être minimisée et la livraison de gaz aux points terminaux du réseau maximisée, est présenté ; l'ensemble des solutions non dominées est répresenté sur un front de Pareto. Enfin l'impact d'injection d'hydrogène dans le RTGN est analysé en introduisant un troisième critère : le pourcentage d'hydrogène injecté dans le réseau que l'on doit maximiser. Dans les deux cas multiobjectifs, des méthodes génériques d'aide à la décision multicritère sont mises en oeuvre pour déterminer les meilleures solutions parmi toutes celles déployées sur les fronts de Pareto. / The optimization of a natural gas transportation network (NGTN) is typically a multiobjective optimization problem, involving for instance energy consumption minimization at the compressor stations and gas delivery maximization. However, very few works concerning multiobjective optimization of gas pipelines networks are reported in the literature. Thereby, this work aims at providing a general framework of formulation and resolution of multiobjective optimization problems related to NGTN. In the first part of the study, the NGTN model is described. Then, various multiobjective optimization techniques belonging to two main classes, scalarization and evolutionary, commonly used for engineering purposes, are presented. From a comparative study performed on two mathematical examples and on five process engineering problems (including a NGTN), a variant of the multiobjective genetic algorithm NSGA-II outmatches the classical scalararization methods, Weighted-sum and ε-Constraint. So NSGA-II has been selected for performing the triobjective optimization of a NGTN. First, the monobjective problem related to the minimization of the fuel consumption in the compression stations is solved. Then a biojective problem, where the fuel consumption has to be minimized, and the gas mass flow delivery at end-points of the network maximized, is presented. The non dominated solutions are displayed in the form of a Pareto front. Finally, the study of the impact of hydrogen injection in the NGTN is carried out by introducing a third criterion, i.e., the percentage of injected hydrogen to be maximized. In the two multiobjective cases, generic Multiple Choice Decision Making tools are implemented to identify the best solution among the ones displayed of the Pareto fronts.