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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

Modelagem de dados de equil?brio para misturas de CO2 e hidrocarbonetos leves sob altas press?es

Nunes, Hugo de Paiva 29 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-13T19:30:58Z No. of bitstreams: 1 HugoDePaivaNunes_DISSERT.pdf: 2913431 bytes, checksum: b94ab79311730ca61ab47671efb0b8f2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-14T18:51:47Z (GMT) No. of bitstreams: 1 HugoDePaivaNunes_DISSERT.pdf: 2913431 bytes, checksum: b94ab79311730ca61ab47671efb0b8f2 (MD5) / Made available in DSpace on 2017-02-14T18:51:47Z (GMT). No. of bitstreams: 1 HugoDePaivaNunes_DISSERT.pdf: 2913431 bytes, checksum: b94ab79311730ca61ab47671efb0b8f2 (MD5) Previous issue date: 2016-07-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Devido ? grande quantidade de compostos presentes no petr?leo bruto, por exemplo, hidrocarbonetos e o di?xido de carbono, faz-se necess?rio o conhecimento das propriedades termodin?micas dessas misturas e do Equil?brio L?quido-Vapor, pois os processos industriais para obten??o de seus derivados: gasolina, diesel, nafta, querosene, entre outros, utilizam essas propriedades para determina??o das quantidades de calor e trabalho necess?rias ? realizar esses processos. Para fluidos, essas propriedades s?o frequentemente avaliadas a partir de medidas do volume molar como fun??o da temperatura e da press?o, fornecendo rela??es entre press?o, volume e temperatura (PVT), as quais podem ser expressas como equa??es de estado. Esta disserta??o consiste em elencar e avaliar a consist?ncia termodin?mica de dados experimentais de equil?brios dispon?veis na literatura, para os sistemas bin?rios (CO2 ? CH4/C2H6/C3H8/C4H10) e tern?rios (CO2/CH4/C2H6 e CO2/ CH4/C3H8) com temperaturas variando na faixa de 207 ? 419,9 K, e press?es de 0,389 ? 84,080 atm. Assim, utilizou-se a equa??o de estado c?bica de Peng-Robinson e regra de mistura de Van der Waals quadr?tica para a estima??o dos par?metros (Kij), por meio do simulador SPECS com os dados selecionados, afim de fornecer uma base para a descri??o quantitativa do comportamento de fluidos reais e correla??es generalizadas que permitam a predi??o do comportamento PVT de fluidos para os quais n?o h? disponibilidade de dados experimentais. Os erros m?dios observados para a correla??o dos sistemas bin?rios foi de at? 5%, j? para os tern?rios a predi??o apresentou erros ligeiramente maiores de at? 7%, sendo a EDEC PR eficiente nos c?lculos destes sistemas, pela modelagem simples, por?m, com descri??es quantitativa e car?ter preditivo satisfat?rio. / Due to the large amount of compounds present in the crude oil, for example, hydrocarbons and carbon dioxide, it is necessary knowledge of the thermodynamic properties of these mixtures and the vapor-liquid equilibrium, as industrial processes for obtaining their derivatives gasoline, diesel, naphtha, kerosene, among others, use these properties to determine the quantities of heat and work necessary to carry out these processes. For fluid, these properties are often evaluated from measurements of the molar volume as a function of temperature and pressure, providing relationships between pressure, volume and temperature (PVT), which can be expressed as state equations. This paper consists of listing and evaluating the thermodynamic consistency experimental data balances available in the literature for the binary systems (CO2 - CH4/C2H6/C3H8/C4H10) and ternary (CO2/CH4/C2H6 and CO2/CH4/C3H8) with temperatures in the range of 207 to 419,9 K and pressures of 0,389 up to 84,080 atm. Thus, we used the cubic equation of state Peng-Robinson and Van der Walls quadratic mixing rule for the estimation of parameters (Kij) through SPECS simulator with the data selected in order to provide a basis for the description quantitative real behavior of fluids and generalized correlations which allow the prediction of PVT behavior of fluids for which there is availability of experimental data. The average errors observed for the correlation of binary systems was up 5%, while for the ternary prediction showed slightly larger errors of up to 7%, the cubic equation PR efficient in the calculations of these systems, for the simple modeling, but with quantitative descriptions and satisfactory predictive character.
2

Estudo de um sistema h?brido de destila??o solar para polimento de ?guas produzidas

Ramos, Rafael Eug?nio Moura 28 May 2012 (has links)
Made available in DSpace on 2014-12-17T15:01:29Z (GMT). No. of bitstreams: 1 RafaelEMR_DISSERT.pdf: 3658891 bytes, checksum: 915aceff21c337d579cbf07b03a0e86a (MD5) Previous issue date: 2012-05-28 / The oil industry, experiencing a great economic and environmental impact, has increasingly invested in researches aiming a more satisfactory treatment of its largest effluent, i.e., produced water. These are mostly discarded at sea, without reuse and after a basic treatment. Such effluent contains a range of organic compounds with high toxicity and are difficult to remove, such as polycyclic aromatic hydrocarbons, salts, heavy metals, etc.. The main objective of this work was to study the solar distillation of produced water pre-treated to remove salts and other contaminants trough of a hybrid system with a pre-heater. This developed apparatus was called solar system, which consists of a solar heater and a conventional distillation solar still. The first device consisted of a water tank, a solar flat plate collector and a thermal reservoir. The solar distillator is of simple effect, with 1m2 of flat area and 20? of inclination. This dissertation was divided in five steps: measurements in the solar system, i.e. temperatures and distillate flow rate and weather data; modeling and simulation of the system; study of vapor-liquid equilibrium of the synthetic wastewater by the aqueous solution of p-xylene; physical and chemical analyses of samples of the feed, distillate and residue, as well as climatology pertinent variables of Natal-RN. The solar system was tested separately, with the supply water, aqueous NaCl and synthetic oil produced water. Temperature measurements were taken every minute of the thermal reservoir, water tank and distillator (liquid and vapor phases). Data of solar radiation and rainfall were obtained from INPE (National Institute for Space Research). The solar pre-heater demonstrated to be effective for the liquid systems tested. The reservoir fluid had an average temperature of 58?C, which enabled the feed to be pre-heated in the distillator. The temperature profile in the solar distillator showed a similar behavior to daily solar radiation, with temperatures near 70?C. The distillation had an average yield of 2.4 L /day, i.e., an efficiency of 27.2%. Mathematical modeling aided the identification of the most important variables and parameters in the solar system. The study of the vapor-liquid equilibrium from Total Organic Carbon (TOC) analysis indicated heteroazeotropia and the vapor phase resulted more concentrated in p-xylene. The physical-chemical analysis of pH, conductivity, Total Dissolved Solids (TDS), chlorides, cations (including heavy metals) and anions, the effluent distillate showed satisfactory results, which presents a potential for reuse. The climatological study indicates the region of Natal-RN as favorable to the operation of solar systems, but the use of auxiliary heating during periods of higher rainfall and cloud cover is also recommended / A ind?stria do petr?leo, sentindo um grande impacto econ?mico e ambiental, tem investido crescentemente em pesquisas visando a um tratamento mais satisfat?rio de seu maior efluente: as ?guas produzidas em campos de produ??o. Estas s?o, em sua maioria, descartadas no mar, sem aproveitamento, ap?s serem tratadas. Esse tipo de efluente cont?m uma gama de compostos org?nicos de alta toxicidade e dif?cil remo??o, como hidrocarbonetos polic?clicos arom?ticos, al?m de sais, metais pesados etc. O objetivo principal desse trabalho foi estudar a destila??o solar da ?gua de produ??o pr?-tratada para remo??o de sais e contaminantes da mesma a partir do uso de um sistema h?brido com pr?-aquecimento. Este aparato desenvolvido foi denominado de sistema solar, que ? composto por um aquecedor solar convencional e um destilador solar; o primeiro constitui-se de uma caixa d'?gua, uma placa coletora solar plana e um reservat?rio t?rmico; o destilador solar ? de simples efeito, com 1m2 de ?rea ?til e 20? de inclina??o na cobertura. A metodologia consistiu em cinco etapas: experimentos no sistema solar, com medi??o de temperaturas e de destilado obtido e obten??o de dados climatol?gicos; modelagem e simula??o do sistema; estudo de equil?brio l?quido-vapor de um efluente modelo de solu??o aquosa de p-xileno; realiza??o de an?lises f?sico-qu?micas de amostras de alimenta??o, destilado e res?duo; e um estudo climatol?gico da cidade de Natal-RN. O sistema solar foi testado, separadamente, com ?gua de abastecimento, solu??o aquosa sint?tica de NaCl e ?gua produzida de petr?leo. Foram realizadas medi??es de temperatura, a cada minuto, no reservat?rio t?rmico, na caixa d??gua e no destilador (fases l?quida e vapor). Dados de radia??o solar e precipita??o pluviom?trica foram obtidos do INPE (Instituto Nacional de Pesquisas Espaciais). O pr?-aquecimento solar mostrou-se eficiente para os l?quidos testados e o fluido no reservat?rio t?rmico apresentou uma temperatura m?dia de 58 ?C, o que viabilizou a alimenta??o aquecida no destilador. O perfil de temperaturas no destilador solar apresentou comportamento similar ? radia??o solar di?ria, com temperaturas m?ximas pr?ximas a 70 ?C. Esse equipamento teve rendimento m?dio de 2,52 L/d e efici?ncia m?dia de 27,2%. A modelagem matem?tica permitiu identificar as vari?veis e par?metros mais influentes no sistema solar. O estudo do equil?brio l?quido-vapor, a partir de an?lise de TOC, indicou condi??o de heteroazeotropia, com o p-xileno se concentrando na fase vapor. As an?lises f?sico-qu?micas de pH, condutividade, STD, cloretos, c?tions (incluindo metais pesados) e ?nions, do efluente destilado apresentaram resultados satisfat?rios, o que evidencia um potencial de reuso. O estudo climatol?gico indica a cidade ou a regi?o de Natal-RN como favor?vel ? opera??o de sistemas solares, mas o uso de aquecimento auxiliar nos per?odos de maior pluviosidade e nebulosidade ? recomendado
3

Estudo do equil?brio l?quido-vapor do sistema ?gua+etanol+l?quido i?nico visando a separa??o do ?lcool anidro

Maciel, J?ssica Caroline da Silva Linhares 21 September 2012 (has links)
Made available in DSpace on 2014-12-17T15:01:30Z (GMT). No. of bitstreams: 1 JessicaCSLM_DISSERT.pdf: 2011571 bytes, checksum: 8e087d35d6e4c83d4f7eda24cd8d3e57 (MD5) Previous issue date: 2012-09-21 / Anhydrous ethanol is used in chemical, pharmaceutical and fuel industries. However, current processes for obtaining it involve high cost, high energy demand and use of toxic and pollutant solvents. This problem occurs due to the formation of an azeotropic mixture of ethanol + water, which does not allow the complete separation by conventional methods such as simple distillation. As an alternative to currently used processes, this study proposes the use of ionic liquids as solvents in extractive distillation. These are organic salts which are liquids at low temperatures (under 373,15 K). They exhibit characteristics such as low volatility (almost zero/ low vapor ), thermal stability and low corrosiveness, which make them interesting for applications such as catalysts and as entrainers. In this work, experimental data for the vapor pressure of pure ethanol and water in the pressure range of 20 to 101 kPa were obtained as well as for vapor-liquid equilibrium (VLE) of the system ethanol + water at atmospheric pressure; and equilibrium data of ethanol + water + 2-HDEAA (2- hydroxydiethanolamine acetate) at strategic points in the diagram. The device used for these experiments was the Fischer ebulliometer, together with density measurements to determine phase compositions. The experimental data were consistent with literature data and presented thermodynamic consistency, thus the methodology was properly validated. The results were favorable, with the increase of ethanol concentration in the vapor phase, but the increase was not shown to be pronounced. The predictive model COSMO-SAC (COnductor-like Screening MOdels Segment Activity Coefficient) proposed by Lin & Sandler (2002) was studied for calculations to predict vapor-liquid equilibrium of systems ethanol + water + ionic liquids at atmospheric pressure. This is an alternative for predicting phase equilibrium, especially for substances of recent interest, such as ionic liquids. This is so because no experimental data nor any parameters of functional groups (as in the UNIFAC method) are needed / O etanol anidro tem ampla aplica??o em ind?strias qu?mica, farmac?utica e de combust?veis. No entanto, os processos atuais para a sua obten??o envolvem custo elevado, alta demanda de energia e a utiliza??o de solventes t?xicos e poluentes. Esse problema ocorre devido ? forma??o de aze?tropo na mistura etanol + ?gua, n?o permitindo a separa??o completa por m?todos convencionais tais como destila??o simples. Como uma alternativa aos processos atualmente utilizados, este estudo prop?e a utiliza??o de l?quidos i?nicos como agentes na destila??o extrativa. Trata-se de sais org?nicos l?quidos a baixas temperaturas (abaixo de 373,15 K). Suas caracter?sticas, tais como baixa volatilidade (press?o de vapor muito baixa), estabilidade t?rmica e baixa corrosividade os tornam interessantes para aplica??es como catalisadores e solventes. Neste trabalho, dados experimentais de press?o de vapor de etanol e ?gua puros na faixa de press?o de 20 a 101 kPa, assim como dados de equil?brio l?quido-vapor(ELV) do sistema etanol + ?gua a press?o atmosf?rica, e dados de equil?brio do sistema etanol + ?gua + 2-HDEAA (acetato de 2-hidrodietanolamina) foram obtidos em pontos estrat?gicos do diagrama. O dispositivo usado para esses experimentos foi o ebuliometro de Fischer, juntamente com medidas de densidade para determinar a composi??o das fases. Os dados obtidos apresentaram coer?ncia com dados da literatura e consist?ncia termodin?mica, desta forma, a metodologia foi devidamente validada. Os resultados foram favor?veis, com o aumento da concentra??o de etanol na fase vapor, por?m o aumento n?o demonstrou ser elevado. O modelo preditivo COSMO-SAC (COnductor-like Screening MOdels Segment Activity Coefficient), desenvolvido por Lin e Sandler (2002), foi aplicado para os c?lculos de predi??o de Equil?brio L?quido-Vapor do sistema etanol + ?gua com l?quido i?nico a press?o atmosf?rica. Essa ? uma alternativa para a previs?o do equil?brio de fases, especialmente para subst?ncias de interesse recente, tais como l?quidos i?nicos, uma vez que nem dados experimentais, nem par?metros de grupos funcionais (como no m?todo UNIFAC) s?o necess?rios

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