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Infer?ncia do ponto de orvalho em amostras de g?s natural processadoPaz, Sidrak Jos? da 20 December 2011 (has links)
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Previous issue date: 2011-12-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This dissertation aims to assess the representativeness of the manual chilled mirror analyzer
(model II Chanscope 13-1200-CN-2) used for the determination of condensed
hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic
models equation of state. Additionally, it has been implemented in this study a model for
calculating the dew point of natural gas. The proposed model is a modification of the
equation of state of Peng-Robinson admits that the groups contribution as a strategy to
calculate the binary interaction parameters kij (T) temperature dependence. Experimental
data of the work of Brown et al. (2007) were used to compare the responses of the dew
point of natural gas with thermodynamic models contained in the UniSim process simulator
and the methodology implemented in this study. Then two natural gas compositions were
studied, the first being a standard gas mixture gravimetrically synthesized and, second, a
mixture of processed natural gas. These experimental data were also compared with the
results presented by UniSim process simulator and the thermodynamic model implemented.
However, data from the manual analysis results indicated significant differences in
temperature, these differences were attributed to the formation of dew point of water, as we
observed the appearance of moisture on the mirror surface cooling equipment / O presente trabalho de disserta??o tem por objetivo avaliar a representatividade
do analisador manual de espelho refrigerado (Chanscope II modelo 13-1200-C-N-2) usado
para a determina??o do condensado de hidrocarbonetos de g?s natural frente aos m?todos
indiretos, fundamentados em modelos termodin?micos de equa??o de estado.
Adicionalmente, tem sido implementado neste estudo um modelo para c?lculo do ponto de
orvalho de g?s natural. O modelo proposto constitui uma modifica??o na equa??o de estado
de Peng-Robinson que admite a contribui??o de grupos como estrat?gia para calcular os
par?metros de intera??o bin?ria kij(T) com depend?ncia da temperatura. Dados
experimentais do trabalho de Brown et al. (2007) foram utilizados para comparar as
respostas de ponto de orvalho do g?s natural com os modelos termodin?micos contidos no
simulador de processo UniSim e com a metodologia implementada neste estudo. Em
seguida, duas composi??es de g?s natural foram estudadas, sendo a primeira uma mistura
padr?o de g?s sintetizada gravimetricamente e, a segunda, uma mistura de g?s natural
processado. Tais dados experimentais foram tamb?m comparados com os resultados
apresentados pelo simulador de processo UniSim e pelo modelo termodin?mico
implementado. No entanto, os dados do analisador manual indicaram diferen?as
significativas nos resultados de temperaturas, sendo estas diferen?as atribu?das ? forma??o
de ponto de orvalho de ?gua, j? que foi observado o aparecimento de umidade sobre a
superf?cie do espelho refrigerado do equipamento
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Functional Genetic Analysis Reveals Intricate Roles of Conserved X-box Elements in Yeast Transcriptional RegulationVoll, Sarah January 2013 (has links)
Understanding the functional impact of physical interactions between proteins and
DNA on gene expression is important for developing approaches to correct disease-associated gene dysregulation. I conducted a systematic, functional genetic analysis of protein-DNA interactions in the promoter region of the yeast ribonucleotide reductase
subunit gene RNR3. I measured the transcriptional impact of systematically
perturbing the major transcriptional regulator, Crt1, and three X-box sites on the
DNA known to physically bind Crt1. This analysis revealed interactions between
two of the three X-boxes in the presence of Crt1, and unexpectedly, a significant
functional role of the X-boxes in the absence of Crt1. Further analysis revealed Crt1-
independent regulators of RNR3 that were impacted by X-box perturbation. Taken
together, these results support the notion that higher-order X-box-mediated interactions
are important for RNR3 transcription, and that the X-boxes have unexpected roles in the regulation of RNR3 transcription that extend beyond their interaction with Crt1.
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Développement d'une méthode de contributions de groupes pour le calcul du coefficient d'interaction binaire de l'équation d'état de Peng-Robinson et mesures d'équilibres liquide-vapeur de systèmes contenant du CO2 / Agroup contribution method to calculate the binary interaction parmeter of the Peng-Robinson equation of state and vapor-liquid equilibria measurements for systems containing CO2Vitu, Stéphane 06 November 2007 (has links)
Nous avons développé une méthode de contributions de groupes permettant d'estimer, en fonction de la température, le coefficient d'interaction binaire (kij) de l'équation d'état de Peng Robinson. Notre approche rend cette équation d'état prédictive. Douze groupes sont définis et il est possible d'estimer les kij pour n'importe quel mélange renfermant des alcanes, des aromatiques, des naphtènes et du CO2. Les diagrammes de phase et lieux des points critiques des systèmes binaires sont bien prédits par le modèle baptisé PPR78 (Predictive 1978, Peng Robinson equation of state). Ce modèle permet également de traiter efficacement les mélanges multiconstituants comme les pétroles bruts et les gaz naturels. A l'aide d'une cellule haute pression, des mesures d'équilibres liquide - vapeur ont été réalisées pour la première fois sur deux systèmes binaires : CO2 méthylcyclopentane et CO2 isopropylcyclohexane. Des mesures ont également été faites sur un mélange renfermant du CO2 et cinq hydrocarbures / A group contribution method allowing the estimation of the temperature dependent binary interaction parameter (kij) for the Peng Robinson equation of state is proposed. Doing so, a new predictive thermodynamic model is born. Twelve groups are defined and it is now possible to estimate the kij for any mixture containing alkanes, aromatics, naphthenes and CO2, whatever the temperature. The model, called PPR78 (Predictive 1978, Peng Robinson equation of state), gives a good description of the phase diagrams and critical locus of binary systems. This predictive model can be successfully employed for the simulation of many mixtures such as natural gases and petroleum fluids. Using a high pressure visual cell, vapor liquid equilibria measurements were made for two binary systems: CO2 methylcyclopentane and CO2 isopropylcyclohexane. For these two systems, no literature data were available. Finally, we measured bubble and dew points on a five component hydrocarbon mixture in the presence of CO2
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