Dissociation of gas hydrates has been the primary concern of the oil and gas industry for flow assurance, mainly in an offshore environment. There is also a growing interest in the rapid formation of gas hydrates for gas storage, transport of natural gas and carbon sequestration. In this thesis, we experimentally measure the kinetics of formation and dissociation of methane hydrates and the effect of various anionic and cationic surfactants such as sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and alpha olefin sulfonate (AOS) on the association/dissociation rate constants. The importance and necessity of micelle formation in these surfactants has been studied. The effect of foam generation on the rate of formation of these hydrates has also been measured. SDS was found to significantly decrease the induction time for hydrate formation. There was an added decrease in the induction time when a foamed mixture of water and SDS was used. On the other hand CTAB and AOS had an inhibiting effect. The contribution of micelles towards promoting hydrate formation was demonstrated with a series of experiments using SDS. The micelles formed by these surfactants appear to serve as nucleation sites for the association of hydrates. New experimental data is presented to show that some surfactants and the use of foam can significantly increase the rate of hydrate formation. Other surfactants are shown to act as inhibitors. A new experimental setup is presented that allows us to distinguish between surfactants that act as promoters and inhibitors for hydrate formation. / text

Made available in DSpace on 2014-12-17T14:27:09Z (GMT). No. of bitstreams: 1 FabioACCML.pdf: 1705634 bytes, checksum: f22226bd97d25642406a8283a0b23a25 (MD5) Previous issue date: 2008-07-24 / In a country of continental dimensions as Brazil, one of the top challenges to its economic growth is the logistic related to energetical demand supply. We live now in the era of environmental protection and, in this new context of priorizations, it passes trough the search for alternative energies for the energetic matrix, due the petroleum elevated costs in the global market (and its finitude), but also due its pollution over the environment. This attempt of substitution needs solutions related to the national reality, into a national long term developing plan and based at a juridical-economic analysis of its realization. This study will look for, also based in an economical analysis, the juridical legitimity of choosing natural gas as the new protagonist of national economic growth (as a substitute of petroleum) and the necessary boost that must be done by law, based on an economic policy focused strictly for that fact, as a modifying agent of this reality. This study, therefore, will always be turned to a constitutional aspect, respecting the principles of economic order and the goal of reducing regional inequalities, which must influence the making off of a developing plan. At the end, it will try to demonstrate the juridical viability of such undertaking, tuned in jus-economical criteria. Another goal is related to the analysis of the natural gas industry, due the regulation of its transport has a major importance for national energetic integration, not only because this activity be characterized as a net industry, still under control of a natural monopoly, but also because the competitive or cooperative profile that should be priorized at the beginning of the economic planning for this activity (such as investment policies and its own rules that will submit private agents) / Em um pa?s de dimens?es continentais como o Brasil, tem-se como um dos principais desafios para o seu crescimento econ?mico a quest?o log?stica relativa ? capacidade de suprimento de demanda energ?tica. Vive-se atualmente a era da defesa do meio ambiente e, neste novo contexto de prioriza??es, passa-se pela busca da substitui??o da matriz energ?tica, seja pela necessidade decorrente dos altos custos do petr?leo no plano internacional (e da finitude das reservas), como tamb?m pelo grave desgaste ecol?gico por ele gerado. Essa tentativa de substitui??o precisa de solu??es focadas na realidade nacional, num plano estrat?gico de desenvolvimento a longo prazo e na an?lise da viabilidade jur?dico-econ?mica da sua realiza??o. Buscar-se-?, neste estudo, sem descurar de uma an?lise econ?mica de fundo, verificar a legitimidade jur?dica da op??o pelo g?s natural como novo protagonista do desenvolvimento nacional (em substitui??o ao petr?leo) e a necess?ria indu??o a ser exercida pelo direito, via uma pol?tica econ?mica voltada estritamente para tal fato, como agente modificador dessa realidade. O estudo, portanto, estar? voltado sempre no plano constitucional, subordinado aos princ?pios da ordem Econ?mica e da busca pela redu??o das desigualdades regionais, que devem permear a elabora??o do plano de desenvolvimento. Procurar-se-? demonstrar, ao final, a viabilidade jur?dica do empreendimento, sintonizada em crit?rios jus-econ?micos, e tamb?m que, na ind?stria do g?s natural, a regula??o do seu setor de transporte exerce import?ncia crucial para a integra??o energ?tica nacional, n?o apenas por se tratar tal atividade de uma ind?stria de rede, ainda sujeita ao monop?lio natural de uma ?nica empresa, mas tamb?m pelo perfil competitivo ou cooperativo a ser priorizado quando se for desenvolver o planejamento econ?mico do setor (tanto a pol?tica de investimentos, quanto ?s pr?prias regras que submeter?o os agentes econ?micos privados)