Orientador: Sergio Valdir Bajay / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-14T02:09:38Z (GMT). No. of bitstreams: 1 Sousa_FranciscoJoseRochade_M.pdf: 2082998 bytes, checksum: 6b17535d59d9d8fe0bb7be02166c05d0 (MD5) Previous issue date: 2009 / Resumo: O objetivo desta dissertação é ampliar a compreensão da geração termelétrica, em particular das termelétricas a gás natural, e da relação entre os setores elétrico e de gás natural no Brasil. Especial atenção é conferida aos leilões públicos de energia, particularmente aqueles na modalidade disponibilidade de energia, opção que tem permitido a contratação de empreendimentos termelétricos a combustíveis fósseis. O trabalho faz avaliação da atratividade do investimento em térmica a Gás Natural Liquefeito - GNL já contratada em leilões públicos. Traz, também, estimativa da competitividade de termelétricas, com ênfase para as termelétricas a GNL. Verificou-se que a capacidade instalada das termelétricas a gás natural deverá ser significativamente ampliada até 2017, o que reforçará o vínculo entre os setores elétrico e de gás natural. Foi constatado que o custo de geração em uma termelétrica a gás natural é fortemente influenciado pelo período de tempo durante o qual ela permanece em operação e pelo preço do gás natural. Adicionalmente, constatou-se que o investimento na construção das termelétricas a GNL contratadas na modalidade disponibilidade de energia mostra-se bastante atrativo / Abstract: The objective of this thesis is to improve the understanding of thermal power, in particular natural-gas-fired power plants, and the relationship between the power sector and the natural gas sector in Brazil. Close attention is paid to the public auctions to hire energy, especially the ones aimed at hiring capacity, option which has allowed the hiring of fossil-fuel power plants. The thesis gives an idea of the attractiveness of the investment in a Liquefied Natural Gas - LNG powered plant hired in a public auction. It also presents an assessment of the competitiveness of thermal plants, with emphasis to the LNG-fired power plants. It was learnt that the natural-gasfired power plant capacity will increase significantly until 2017, which will reinforce the bond between the power sector and the natural gas sector. Another important finding is that the generation cost of a natural-gas-fired power plant is strongly influenced by the length of time it operates and by the natural gas price. Furthermore, the study shows that the investment in the construction of a LNG powered plant hired in a public auction is very attractive / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos

This thesis focuses on the process of liberalization of the natural gas market in Europe. The aim of this thesis is to present energy policy and its development in relation to the liberalization of the gas industry in the EU. Moreover another aim of this thesis is to bring a critical look at the process of liberalization of natural gas market in practice and assess the current stage of the liberalization process in EU. The gas industry represents one of the parts of energy industry and from this reason the indroduction of this thesis is devoted to the development of energy and energy policy from the 2nd world war to the present. The next chapter of this thesis is focuses on the importance and the position of natural gas among the other energy sources. The next chapter describes the process of the liberalization in the European Union, which is related to the adoption and implementation of the European energy directives and regulations, also known as the energy packages, in to the national legislation. In the last chapter are analyzed some of the factors of the liberalization of the gas market in the Czech Republic

This thesis deals with the characteristics of natural gas and the problems of transport. Furthermore, this work deals with the most commonly used thermodynamic cycles, both steam and gas and their applications in the energy industry. The main part of this thesis focuses on the calculation of the thermodynamic properties of the gas, determine the minimum temperature gas after expansion in the turbine to prevent the formation of hydrates, design calculation of main dimensions and thermodynamic parameters of the expansion turbine on natural gas. As a final design will be drawn slice computed expansion turbine.

Rapporté à la tonne de fret, le trafic maritime est un mode de transport relativement « propre ». Néanmoins, par l’intensification des échanges mondiaux, sa part dans les émissions de Gaz à Effet de Serre (GES) au niveau mondial est appelée à augmenter. Conscients des effets néfastes associés aux GES, les pays membres des nations unies, via l’organisation maritime internationale, imposent le cadre réglementaire pour que ce secteur, vital dans une économie mondialisée, demeure écologiquement acceptable. Des objectifs ambitieux sont établis à court (2020) et moyen terme (2050). Or, d’après l’hypothèse faible de Porter, fixer des objectifs environnementaux sans imposer les moyens à mettre en oeuvre favorise l’innovation. Aussi, dans l’industrie du « shipping », les solutions fleurissent au premier rang desquelles figure l’emploi du Gaz Naturel Liquéfié (GNL) en tant que combustible. D’un point de vue thermodynamique, les inévitables infiltrations thermiques à travers les parois des réservoirs cryogéniques entraînent une variation de la pression dans le réservoir et des fluctuations de la qualité du gaz à l’admission moteur. Selon le schéma d’exploitation navire, ces deux phénomènes impactent significativement la pertinence de l’option GNL. En réponse, cette thèse propose un ensemble de modèles 0D pour, à partir d’un profil opérationnel, évaluer :1. l’évolution de la pression dans les réservoirs ;2. l’évolution de la qualité du gaz à l’admission moteur.Dans une première partie, des modèles sont proposés pour simuler les infiltrations thermiques à travers le réservoir, l’évaporation du GNL, son vieillissement (altération des propriétés du gaz par évaporation différenciée des composés) et l’évolution du taux de méthane à l’admission moteur. Puis, les modèles sont assemblés à travers une étude de cas apportée par un acteur du transport maritime. / In proportion to the ton of cargo, shipping is a relatively “clean” transportation mode. Nevertheless, due to global trade intensification, its share in the global greenhouse gas (GHG) emissions should increase. Aware that GHG adverse effects are a major concern for humanity, united nation member states impose, via the international maritime organization, a regulatory framework so that this vital sector in a global economy remains sustainable. Short (2020) and medium (2050)-term goals are set. According to the weak version of Porter’s hypothesis, strict environmental regulations encourage innovations. Hence, in the shipping industry solutions flourish among which the use of Liquefied Natural Gas (LNG) as a fuel. On a thermodynamic basis, the unavoidable heat leaks into the cryogenic tanks cause variations of the tank pressure and the natural gas quality at engine inlet. Depending on the ship’s operational profile, those two phenomena will impact significantly the LNG as a fuel option relevance. One major bottleneck slowing the uptake of LNG as a marine fuel is the lack of methods and models to perform, at a concept design level, the feasibility study. In response, this thesis proposes 0D models to assess from the operational profile:1. the tank pressure evolution;2. the gas quality evolution at engine inlet.In the first part, models are proposed to simulate heat leaks into the tanks, LNG vaporization, ageing (the alteration of natural gas thermophysical properties by a differentiate vaporization of its compounds) and methane number evolution at engine inlet. Then, the models are put together and applied on a case study. The ship concept is proposed by a freight company.

Carbon dioxide hydrates were synthesized in a 0.10m I.D. and 1.22m tall bubble column equipped with a cooling jacket for heat removal. Visual observations at different driving forces (pressures between 2.75 and 3.60 MPa and temperatures between 0 and 8ºC) were recorded with a digital camera through a sight glass of 118.8 by 15.6 mm. The superficial gas velocity was varied from 20 to 50 mm/s to attain different levels of turbulence in the liquid. The growth rate was found to be dependent on the sequence/method used to reach the operating temperature and pressure. A greater supersaturation was obtained when the system temperature and pressure were reached with very low or no bubble-induced mixing. As a result, hydrates nucleated and grew immediately when starting the gas flow with the reactor volume being quickly filled with hydrates. Moreover, the hydrate growth rate and solution final density were higher when operating conditions partially condensed CO2 resulting in greater interphase mass transfer rates. In parallel, since hydrate formation is an exothermic process and the reaction is often limited by the rate of heat removal, heat transfer measurements were achieved in a simulated hydrate environment. The instantaneous heat transfer coefficient and related statistics gave insight on the role of bubbles on heat transfer and hydrodynamics.

Die Dissertationsschrift thematisiert die Frage nach den Kosten und Nutzen einer Diversifikationsstrategie im europäischen Erdgasmarkt und gliedert sich in neun Kapitel. In einer Vorbetrachtung beschreiben die Kapitel eins bis vier die Ausganglage mit Blick auf Angebots- und Nachfragestrukturen sowie der Gasinfrastruktur. Unsicherheiten in Bezug auf die Entwicklung der Nachfrage, Importverfügbarkeit und Preisniveaus werden diskutiert. In einem analytischen Rahmen wird das Thema Diversifikation in den Kontext der Energiesicherheit eingeordnet. Die Kapitel fünf bis sieben befassen sich mit der Beschreibung und der Analyse des europäischen Gasmarkts. Dafür wird ein lineares Modell, GAMAMOD-EU, entwickelt, welches als stochastische Optimierung den Ausbau der Erdgasinfrastruktur unter Einbezug von drei Unsicherheitsdimensionen in den Jahren 2030 und 2045 abbildet. Zusätzlich werden drei Diversifikationsstrategien in Hinblick auf Infrastrukturentwicklung und Versorgungssicherheit analysiert. In einer Erweiterung wird der Import Grüner Gase in die Betrachtung einbezogen. Kapitel acht stellt das deutsche Gasnetzmodell GAMAMOD-DE mit einer Fallstudie vor, die die Versorgungslage im kalten Winter 2012 nachmodelliert. Im abschließenden Kapitel neun werden die zu Beginn aufgeworfenen Forschungsfragen beantwortet, politische Handlungsempfehlungen gegeben und der weitere Forschungsbedarf skizziert.:Table of Contents List of Figures List of Tables Abbreviations Country Codes Nomenclature: GAMAMOD-EU Nomenclature: GAMAMOD-DE 1 Introduction 2 Uncertainties in Gas Markets 3 Diversification in Gas Markets to Ensure Security of Supply 4 Natural Gas Infrastructure 5 The European Natural Gas Market Model (GAMAMOD-EU) 6 Results on Security of Supply in the European Gas Market 7 Impact of Green Gas Imports on Infrastructure Investments 8 The German Natural Gas Market Model (GAMAMOD-DE) 9 Conclusion and Outlook Laws and Communication Papers References Appendix / The dissertation addresses the question of the costs and benefits of a diversification strategy in the European natural gas market and is divided into nine chapters. In a preliminary analysis, chapters one to four describe the initial situation with regard to supply and demand structures as well as the gas infrastructure. Uncertainties regarding the development of demand, import availability and price levels are discussed. In an analytical framework, the topic of diversification is placed in the context of energy security. Chapters five to seven deal with the description and analysis of the European gas market. For this purpose, a linear model, GAMAMOD-EU, is developed, which maps the expansion of the natural gas infrastructure as a stochastic optimisation, taking into account three uncertainty dimensions in the years 2030 and 2045. In addition, three diversification strategies are analysed with regard to infrastructure development and security of supply. In an extension, the import of green gases is included in the analysis. Chapter eight presents the German gas grid model GAMAMOD-DE with a case study, which models the supply situation in the cold winter of 2012. In the concluding chapter nine, the research questions raised at the beginning are answered, political recommendations for action are given and the need for further research is outlined.:Table of Contents List of Figures List of Tables Abbreviations Country Codes Nomenclature: GAMAMOD-EU Nomenclature: GAMAMOD-DE 1 Introduction 2 Uncertainties in Gas Markets 3 Diversification in Gas Markets to Ensure Security of Supply 4 Natural Gas Infrastructure 5 The European Natural Gas Market Model (GAMAMOD-EU) 6 Results on Security of Supply in the European Gas Market 7 Impact of Green Gas Imports on Infrastructure Investments 8 The German Natural Gas Market Model (GAMAMOD-DE) 9 Conclusion and Outlook Laws and Communication Papers References Appendix

Master of Science / Geology / Matthew Kirk / The Cherokee basin in southeastern Kansas is a declining coalbed methane (CBM) field where little is known about how the CBM formed, the extent to which it continues to form, and what factors influence its formation. An understanding of methanogenic processes and geochemistry could lead to potential enhancement of methane formation in the basin. The objectives of this project are to (1) determine the pathway of methane formation and (2) determine whether geochemistry has influenced gas formation. In order to reach the objectives, we analyzed formation water geochemistry, production history, and gas composition and isotopes. Post Rock Energy Corporation gave us access to 16 wells for sampling purposes. We collected gas samples in Isotubes® for compositional and isotopic analyses at a commercial laboratory. We analyzed major ion chemistry from formation water using standard methods. Co-produced water samples we collected are Na-Cl type with total dissolved solids content ranging from 35,367 to 91,565 mg/L. TDS tended to be highest in samples collected from wells with greater total depth. The pH and temperature of sampled water averaged 7.0 and 19°C with an alkalinity ranging from 3.33 to 8.59. Gas dryness and δ¹³C CH[subscript 4] range from 196 to 4531 and -69.95 to -56.5, respectively, which indicate that methane is being produced biologically. Comparing the δ¹³C CH[subscript 4] to the δD CH[subscript 4], which ranges from -228.2 to -217.2, suggest that the primary pathway of methanogenesis is H[subscript 2]/CO[subscript 2] reduction. We calculated Δ (the difference between δ values) in order to correlate isotope data to produced water chemistry. Samples ΔD and Δ¹³C values range from -189.1 to -168.7 and 61.52 to 69.99. Calculated ΔD[subscript CH4-H2O] and Δ¹³C[subscript CO2-CH4] values approach the range for the acetate/methyl pathways as Clˉ concentration increases, potentially indicating a slight shift in methanogenic pathway in deeper, more saline portions of the basin. The culturing results revealed that living methanogens are still able to utilize H[subscript 2], acetate, and methanol present in co-produced formation water from all tested wells.

The presence of gas and oil in some sand formations decreases the seismic velocity and density to such an extent that anomalously large reflections coefficients are encountered at fluid contacts. Geerstma and Gassmann's theories are equivalent and provide a good way to study the physical properties that affect the elastic behavior of the porous rock. The fluid-contact reflectivity (gas-water, oil-water) can be well estimated based on the brine saturated velocity alone. A comparison between the estimated and observed fluid-contact reflectivities on seismic and well log data from an Offshore prospect showed a remarkable agreement. / text

A spark ignition engine was retrofitted to operate on biogas fuel. Biogas was synthetically generated through the mixing of various pure gases. The air-fuel ratio was accurately controlled using a closed feedback system consisting of flow controllers and a wide range oxygen sensor. A natural gas catalytic converter was implemented with the use of biogas fuel. To achieve full NOx and CO reduction the engine was required to run at a slightly rich equivalence ratio. Methane emissions posed to be the hardest to reduce across the catalyst. The biogas fuel composition had no effect on the catalyst performance. The catalyst performance was only affected by exhaust temperature and equivalence ratio. The catalyst requires tight A/F ratio control for optimal performance. A Catalytic converter can be used to reach low emissions but requires the knowledge of the biogas fuel composition.

A spark ignition engine was retrofitted to operate on biogas fuel. Biogas was synthetically generated through the mixing of various pure gases. The air-fuel ratio was accurately controlled using a closed feedback system consisting of flow controllers and a wide range oxygen sensor. A natural gas catalytic converter was implemented with the use of biogas fuel. To achieve full NOx and CO reduction the engine was required to run at a slightly rich equivalence ratio. Methane emissions posed to be the hardest to reduce across the catalyst. The biogas fuel composition had no effect on the catalyst performance. The catalyst performance was only affected by exhaust temperature and equivalence ratio. The catalyst requires tight A/F ratio control for optimal performance. A Catalytic converter can be used to reach low emissions but requires the knowledge of the biogas fuel composition.