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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.
1

Solubilidade de cloreto de c?lcio em misturas de ?gua e monoetileno glicol pelo m?todo anal?tico via densidade / Calcium chloride solubility in aqueous mixtures of ethylene glycol by the analytical method via density

Silva, I?da Let?cia Mendes 09 November 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T20:20:19Z No. of bitstreams: 1 IedaLeticiaMendesSilva_DISSERT.pdf: 33772951 bytes, checksum: 825956e46d9efc41cc4e776db6779930 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-22T21:57:01Z (GMT) No. of bitstreams: 1 IedaLeticiaMendesSilva_DISSERT.pdf: 33772951 bytes, checksum: 825956e46d9efc41cc4e776db6779930 (MD5) / Made available in DSpace on 2017-03-22T21:57:01Z (GMT). No. of bitstreams: 1 IedaLeticiaMendesSilva_DISSERT.pdf: 33772951 bytes, checksum: 825956e46d9efc41cc4e776db6779930 (MD5) Previous issue date: 2016-11-09 / Dentro do universo da ind?stria petrol?fera, a forma??o de hidratos se apresenta como um dos grandes empecilhos atrelados a po?os produtores de g?s. Uma das t?cnicas utilizadas para evitar a forma??o de hidratos, ? a utiliza??o de compostos inibidores, destacando-se entre esses o monoetilenoglicol (MEG), sendo este injetado na cabe?a dos po?os produtores. No entanto, ao retornar ? superf?cie a corrente de MEG carreia tanto sedimentos como ?gua, advindos das forma??es dos po?os. Dessa forma, a regenera??o do MEG se faz necess?ria para a rentabilidade do processo. A regenera??o do MEG envolve etapas de pr?-tratamento, remo??o de sais e remo??o de ?gua. A fim de otimizar as condi??es operacionais, este trabalho se prop?s a determinar a solubilidade especificamente do sal cloreto de c?lcio em misturas de ?gua e MEG, ?s temperaturas de 25 e 50?C. A metodologia proposta foi a anal?tica e teve por intuito obter dados de solubilidade por meio de aferi??o de grandezas indiretas, sendo elas, densidade e condutividade. Sendo assim, as an?lises desenvolvidas nesse trabalho foram, principalmente, densimetria, condutimetria, e, al?m delas, termogravimetria e titula??o volum?trica de Karl Fischer, utilizadas para a determina??o do teor de ?gua apresentado pelos reagentes. Atrav?s das curvas elaboradas de densidade e condutividade versus concentra??o de cloreto de c?lcio, percebeu-se um comportamento monot?nico da grandeza densidade em rela??o ? concentra??o de sal, enquanto a condutividade apresentou comportamento n?o-monot?nico. Nos experimentos de solubilidade foram coletadas amostras que permitiram determinar a concentra??o a partir dos dados de densidade, grandeza mais adequada para este fim. Foram obtidas isotermas a 25 e 50?C de solubilidade versus concentra??o de MEG na mistura de solventes. A an?lise das isotermas permite observar que o efeito salting-out, provocado pela presen?a do MEG no solvente, ? pouco significativo at? a concentra??o m?dia de 33% m?ssico de MEG livre de sal. No entanto, ap?s esta zona de concentra??o ? percept?vel uma significativa altera??o na inclina??o de ambas as isotermas, e a diminui??o da solubilidade passa a ser mais acentuada. Em rela??o ao aumento de temperatura, a solubilidade do cloreto de c?lcio apresenta efeito positivo. A equa??o de Setchenov e o modelo UNIQUAC+DH, juntamente com os dados termoqu?micos, foram aplicados para descrever os dados experimentais. Na abordagem com UNIQUAC+DH n?o foi considerada a altera??o na fase s?lida formada com a concentra??o de MEG atrav?s dos dados termoqu?micos. Por outro lado, semelhantemente a Setchenov, foram estimados dois conjuntos de par?metros para cada isoterma, considerado cada fase s?lida distinta. A descri??o dos dados pela modelo UNIQUAC+DH resultou pr?xima da incerteza experimental, i.e., em m?dia para a solubilidade do cloreto de c?lcio 2,00 %. / In the oil and gas industry, hydrates formation is one of the issues related to the natural gas production. One of the most employed techniques to avoid hydrates formation is the injection of inhibitors compounds, like the monoethylene glycol (MEG) into the well. However, MEG stream returns to the surface impregnated with water and many salts coming from the rock sediments. Then, MEG must be regenerated to assure process environmental and economic viability. In order to optimize the operationals conditions of the reclamation process, this work aimed to determine the solubility of the calcium chloride in aqueous mixtures of MEG, in the temperatures of 25 and 50?C. The proposed methodology is analytical and applies indirect properties, density and conductivity, to determine solubility data. Therefore, the main data were obtained from densimetry, conductimetry, and beyond them, thermogravimetry and Karl Fischer titration to verify purity and moisture content. Observing the developed curves of density and conductivity versus calcium chloride concentration, it was detected the monotone and linear behavior for the density as function of the salt concentration. However, for the conductivity, it was observed a no-monotone and non-linear behavior. Thus, in order to determine solubility data, samples were evaluated with the aid of concentration versus density calibration data. The developed isotherms illustrate the calcium chloride solubility versus MEG concentration behavior. The isotherms have demonstrated the slight relevance of the salting-out effect, caused by the MEG presence in the solvent, until an average concentration of 33% MEG (salt-free). From that point, there are changes in the inclination of both isotherms and the solubility decreases more pronouncedly. In terms of the temperature increase, the calcium chloride solubility showed a positive effect. Setchenov equation and UNIQUAC+DH model were applied to describe the experimental data. In the UNIQUAC approach, it was not considered the change in the solid phase expressed by the corresponding thermochemical data due to MEG concentration. In the other hand, similarly to Setchenov correlation, two set of parameters were estimated for each isotherm, considering each solid phase formed. The description provided by the UNIQUAC+DH resulted closed to the experimental uncertainty, i.e., in average 2,00 % for the calcium chloride solubility.
2

Determina??o de dados de equil?brio l?quido-vapor a altas press?es para sistemas de hidrocarbonetos assim?tricos

Guerra Neto, Dival de Brito 22 December 2010 (has links)
Made available in DSpace on 2014-12-17T15:01:24Z (GMT). No. of bitstreams: 1 DivalBGN_DISSERT.pdf: 2637921 bytes, checksum: 83fbea74e9888e52417cea5286defdaa (MD5) Previous issue date: 2010-12-22 / Crude oil is a complex liquid mixture of organic and inorganic compounds that are dominated by hydrocarbons. It is a mixture of alkanes from the simplest to more complex aromatic compounds that are present derivatives such as gasoline, diesel, alcohol, kerosene, naphtha, etc.. These derivatives are extracted from any oil, however, only with a very high quality, in other words, when the content of hydrocarbons of low molecular weight is high means that production of these compounds is feasible. The American Petroleum Institute (API) developed a classification system for the various types of oil. In Brazil, the quality of most of the oil taken from wells is very low, so it is necessary to generate new technology to develop best practices for refining in order to produce petroleum products of higher commercial value. Therefore, it is necessary to study the thermodynamic equilibrium properties of its derivative compounds of interest. This dissertation aims to determine vapor-liquid equilibrium (VLE) data for the systems Phenilcyclohexane - CO2, and Cyclohexane - Phenilcyclohexane - CO2 at high pressure and temperatures between 30 to 70oC. Furthermore, comparisons between measured VLE experimental data from this work and from the literature in relation to the Peng- Robinson molecular thermodynamic model, using a simulation program SPECS IVCSEP v5.60 and two adjustable interaction parameters, have been performed for modeling and simulation purposes. Finally, the developed apparatus for determination of phase equilibrium data at high pressures is presented / O petr?leo bruto ? uma complexa mistura l?quida de compostos org?nicos e inorg?nicos em que predominam os hidrocarbonetos, desde os alcanos mais simples at? os arom?ticos mais complexos. Nessa mistura encontram-se presentes derivados como gasolina, diesel, ?lcool, querosene, nafta, g?soleos, etc., estes derivados s?o extra?dos de qualquer petr?leo, por?m, somente os com uma qualidade bastante elevada, ou seja, com teor de hidrocarbonetos de baixo peso molecular alto s?o realmente vi?veis a produ??o destes compostos. A American Petroleum Institute (API) desenvolveu um sistema de classifica??o dos tipos de petr?leo. No Brasil a qualidade da maioria dos petr?leos retirado dos po?os ? muito baixa, sendo assim, ? necess?rio obter novos conhecimentos a fim de desenvolver melhores pr?ticas de refino com o intuito de produzir derivados de petr?leo de alto valor comercial. Para isso se faz necess?rio o estudo de equil?brio termodin?mico de seus derivados. Esta disserta??o de mestrado consiste em determinar dados de equil?brio l?quido-vapor dos sistemas Fenilciclohexano - CO2 e Fenilciclohexano - Ciclohexano e CO2 a alta press?o e temperaturas entre 30 a 70 graus Celsius. Compara??es entres os dados experimentais de equil?brio liquidovapor encontrados no laborat?rio e na literatura foram realizadas em rela??o aos valores obtidos pelo modelo termodin?mico molecular de Peng-Robinson usando o programa computacional SPECS IVCSEP v5.60, com dois par?metros de intera??o ajust?veis, para fins de modelagem e simula??o. Al?m disso, ? apresentado o desenvolvimento de um equipamento de alta press?o no laborat?rio para determina??o de dados de equil?brio de fases

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