Die experimentelle Charakterisierung von Phasengleichgewichten (Flüssigkeit-Dampf und Flüssigkeit-Flüssigkeit) erfolgte in binären und ternären Systemen aus aromatischen bzw. aliphatischen Kohlenwasserstoffen, Phenolen und Wasser. Die Trübungstitration diente der Bestimmung von Flüssigkeit-Flüssigkeit-Gleichgewichten, auftretende koexistierende flüssige Phasen wurden analytisch charakterisiert. Mit Hilfe der dynamischen Methode erfolgte die Bestimmung der Flüssigkeit-Dampf-Gleichgewichte. Die Modellierung der binären Systeme und die Vorausberechnung der ternären Systeme erfolgten mit den Aktivitätskoeffizientenmodellen NRTL und UNIQUAC. Weiterhin wurden die Berechnungen mit der von Elliott, Suresh und Donohue entwickelten Zustandsgleichung (ESD) durchgeführt, welche einen die assoziierenden Wechselwirkungen berücksichtigenden Term beinhaltet. Ferner wurden mit der Gruppenbeitragsmethode UNIFAC die untersuchten binären und ternären Systeme vorausberechnet. Beide Aktivitätskoeffizientenmodelle können bei der simultanen Modellierung der verfügbaren Phasengleichgewichtsdaten für nahezu alle betrachteten binären Systeme mit sehr guten Ergebnissen überzeugen. Bei der Modellierung mit der Zustandsgleichung ESD müssen deutlich höhere Abweichungen akzeptiert werden. Die Ergebnisse der Modellierung der binären Systeme lassen sich nicht adäquat auf die Vorausberechnung der ternären Systeme übertragen. UNIQUAC Modell und Zustandsgleichung ESD zeigen im Mittel die geringsten Unterschiede zwischen vorausberechneten und experimentellen Phasengleichgewichten. Deutlich höhere Abweichungen treten im Mittel bei Verwendung des NRTL Modells bzw. der Gruppenbeitragsmethode UNIFAC auf. Die Annahme, mit Hilfe der expliziten Berücksichtigung der Assoziation mit Zustandsgleichung ESD eine deutliche Verbesserung bei der Vorausberechnung entsprechender Phasengleichgewichten zu erzielen, konnte lediglich für Flüssigkeit-Flüssigkeit-Gleichgewichte in Systemen mit aliphatischen Kohlenwasserstoffen bestätigt werden. / The experimental characterizations of phase equilibria (vapor-liquid and liquid-liquid) were determined in binary and ternary systems containing aliphatic and aromatic hydrocarbons, phenols and water. Liquid-liquid equilibria were measured by turbidity titration. The compositions of coexisting phases were determined with analytic methods. The vapor-liquid equilibria were determined by the dynamic method. The correlation of the binary systems and the prediction of the ternary systems were performed with the activity coefficient models NRTL and UNIQUAC. Furthermore the calculations were realized with an equation of state (ESD) developed by Elliott, Suresh and Donohue, which contain a term for association. Additional predictions of investigated binary and ternary systems were performed with the group contribution method UNIFAC. Both activity coefficient models convinced with satisfactory results by the simultaneously correlation of the available equilibria data for almost all investigated binary systems. The correlations with the ESD equation of state were performed with higher deviations. A transfer of the results of the binary correlations into the ternary predictions is not possible. The UNIQUAC model and the ESD equation of state performed on average with minor deviations between predicted and experimental phase equilibria. Higher deviations were calculated using the NRTL model respectively the group contribution method UNIFAC. Only liquid-liquid equilibria in systems contain aliphatic hydrocarbons indicates improved prediction results based on the consideration of the association.

Made available in DSpace on 2014-12-17T15:01:56Z (GMT). No. of bitstreams: 1 AlessandroALA_TESE.pdf: 2166690 bytes, checksum: 87b921d322f56a3c11d668a0ad8d9341 (MD5) Previous issue date: 2013-11-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The nonionic surfactants when in aqueous solution, have the property of separating into two phases, one called diluted phase, with low concentration of surfactant, and the other one rich in surfactants called coacervate. The application of this kind of surfactant in extraction processes from aqueous solutions has been increasing over time, which implies the need for knowledge of the thermodynamic properties of these surfactants. In this study were determined the cloud point of polyethoxylated surfactants from nonilphenolpolietoxylated family (9,5 , 10 , 11, 12 and 13), the family from octilphenolpolietoxylated (10 e 11) and polyethoxylated lauryl alcohol (6 , 7, 8 and 9) varying the degree of ethoxylation. The method used to determine the cloud point was the observation of the turbidity of the solution heating to a ramp of 0.1 ? C / minute and for the pressure studies was used a cell high-pressure maximum ( 300 bar). Through the experimental data of the studied surfactants were used to the Flory - Huggins models, UNIQUAC and NRTL to describe the curves of cloud point, and it was studied the influence of NaCl concentration and pressure of the systems in the cloud point. This last parameter is important for the processes of oil recovery in which surfactant in solution are used in high pressures. While the effect of NaCl allows obtaining cloud points for temperatures closer to the room temperature, it is possible to use in processes without temperature control. The numerical method used to adjust the parameters was the Levenberg - Marquardt. For the model Flory- Huggins parameter settings were determined as enthalpy of the mixing, mixing entropy and the number of aggregations. For the UNIQUAC and NRTL models were adjusted interaction parameters aij using a quadratic dependence with temperature. The parameters obtained had good adjust to the experimental data RSMD < 0.3 %. The results showed that both, ethoxylation degree and pressure increase the cloudy points, whereas the NaCl decrease / Os tensoativos n?o i?nicos, quando em solu??o aquosa, apresentam a propriedade de separa??o em duas fases, sendo uma denominada de fase dilu?da, baixa concentra??o em tensoativo, e a outra rica em tensoativo denominada de coacervato. A aplica??o deste tipo de tensoativo nos processos de extra??o de solutos de meios aquosos vem aumentando o que implica na necessidade do conhecimento das propriedades termodin?micas desses tensoativos. Neste trabalho foram determinados os pontos de n?voa dos tensoativos polietoxilados, da fam?lia do nonilfenolpolietoxilado variando o grau de etoxila??o (9,5;10;11;12 e 13), da fam?lia do octilfenolpolietoxilado variando o grau de etoxila??o (10 e 11) e do ?lcool laur?lico polietoxilado nos graus de etoxila??o (6;7;8 e 9). O m?todo utilizado para determina??o do ponto de n?voa foi a observa??o do turvamento da solu??o ao aquecer o sistema a uma rampa de 0,1oC/minuto, e no estudo da press?o foi utilizada uma c?lula de alta press?o, m?ximo (300 bar). Atrav?s dos dados experimentais obtidos dos respectivos tensoativos, foram utilizados os modelos de Flory-Huggins, UNIQUAC e NRTL para descrever as curvas do ponto de n?voa dos referidos tensoativos. Foram tamb?m estudados a influ?ncia da concentra??o do NaCl e da press?o no ponto de n?voa. Este ?ltimo par?metro ? importante para os processos de recupera??o avan?ada de petr?leo nos quais os tensoativos em solu??o s?o submetidos a press?es elevadas. Enquanto que o efeito do NaCl permite obter pontos de n?voa a temperaturas mais pr?xima da temperatura ambiente viabilizando sua utiliza??o em processos sem controle de temperatura. O m?todo num?rico utilizado para ajustar os par?metros foi o Levenberg-Marquardt. Para o modelo de Flory-Huggins foram determinados par?metros de ajuste como a entalpia da mistura, entropia da mistura e o n?mero de agrega??o. Para os modelos UNIQUAC e NRTL foram ajustados par?metros de intera??o aij utilizando uma depend?ncia quadr?tica com a temperatura. Os par?metros obtidos tiveram bons ajustes aos dados experimentais com RMSD < 0,3%. Os resultados mostraram que tanto a etoxila??o quanto a press?o aumentam o ponto de n?voa do tensoativo, enquanto que o NaCl diminui

A esterificação do sec-butanol com ácido acético, submetida à catálise homogênea, apresenta poucos resultados experimentais de cinética reacional e equilíbrio químico disponíveis na literatura. A presente dissertação visa determinar os parâmetros cinéticos e de equilíbrio químico desta reação de esterificação, empregando modelo cinético de 2ª ordem baseado em atividades. Os experimentos cinéticos foram realizados em reator batelada com auxílio da metodologia Karl Fischer para análise do teor de água e determinação do perfil de frações molares ao longo da reação. A principal dificuldade na modelagem desta esterificação consistiu em representar satisfatoriamente as não-idealidades da mistura em fase líquida, em espacial nas reações cuja fração molar inicial de ácido acético foi superior a 50%. Netas condições admitiu-se a ocorrência de dissociação do ácido acético levando ao surgimento de interações iônicas. O modelo empregado para obtenção das atividades, com base em frações molares, foi o NRTL. Este modelo representou bem as interações moleculares em condição de baixa acidez, mas apresentou desvios em condições de acidez e teores de água mais elevados. O estudo também visou o desenvolvimento de modelos de calibração para um método analítico on-line visando determinar o perfil de frações molares ao longo da reação. O método empregado foi a espectroscopia de infravermelho próximo (NIR), em vista à capacidade deste método analítico em determinar quantitativamente frações molares de água, além dos demais compostos envolvidos. Outro fator determinante ao emprego do NIR é a seu crescente uso no meio industrial, e o presente trabalho visou também contribuir para o uso futuro desta técnica de monitoramento no processo industrial. Modelos de calibração multivariável com conjuntos de calibração interna por validação cruzada se mostraram adequados ao sistema estudado. Calibrações externas resultaram em modelos imprecisos, não sendo possível determinar claramente os fatores responsáveis pela imprecisão. / There is a lack of literature data on the reaction kinetics and equilibrium of the homogeneously catalyzed esterification of sec-butanol with acetic acid. This work aims at obtaining the kinetic parameters and chemical equilibrium parameters of this esterification reaction by using a second order kinetic model based on activities. The kinetic experiments were performed in a batch reactor and the Karl Fischer analytical method was used to determine the molar fraction of water along the reaction progress. The main challenge of modeling this reaction was to represent the highly non-ideal mixture in liquid phase, specially for reactions runs starting with acetic acid mole fraction higher than 50%. In these conditions, it was assumed the occurrence of acetic acid dissociation that leads to ionic interactions. The thermodynamic model used to calculate the activities was the NRTL. This model predicted well the molecular interactions on low acidity conditions but presented deviations when molar fractions of acid and water were higher. The present study also aims to develop calibration models for analytical on-line method to obtain molar fraction profiles along the reaction. Near infrared spectroscopy (NIR) was used due to the possibility of quantitatively analyze water mole fraction, besides the mole fractions of the other components. Another important reason to choose NIR was its crescent use in industry, and the present work intended to contribute towards the future use of this on line monitoring technique in industrial applications. Multivariate calibration models using internal set of calibration and cross-validation seems to be suitable for this system. External set of calibration leads to less accurate models, and the causes of this lack of accuracy were not clearly identified.

La gazéification de la biomasse par voie thermochimique constitue une ressource en énergie renouvelable ayant un grand potentiel de développement. Parmi les différentes techniques possibles, la voie cogénération Chaleur/bio-SNG (Substitute Natural Gaz) est proche de la maturité technologique. Un des verrous technologique de cette technologie est l’élimination des goudrons contenu dans le gaz issu du gazéifieur. Le présent travail de recherche constitue une contribution à la levée de ce verrou. La technique d’élimination des goudrons par lavage au moyen d’un solvant non miscible à l’eau ayant été sélectionnée pour un pilote de démonstration, le présent travail de recherche s’est principalement focalisé sur l’acquisition de données d’équilibre bi et triphasique des composés modèles des goudrons - eau – solvant de lavage. De telles données sont en effet indispensable pour la mise au point du modèle thermodynamique permettant la modélisation et l’optimisation du lavage. Les analyses des phases liquides en équilibre on été réalisées par CPG-FID ou CPG-SM. Dans certains cas les niveaux de concentration étaient particulièrement faibles. Les concentrations réciproque obtenues et les coefficients de partage qui s’en déduisent vérifie respectivement la corrélation empirique de Hands et la relation de Van’t Hoff. L’équilibre liquide-liquide-vapeur des binaires eau – solvant de lavage ont été étudiés par la méthode statique. Les concentrations des phases en équilibres ont été corrélées par les modèles NRTL et UNIQUAC au moyen du logiciel commercial ‘Simulis Thermodynamic’. Les paramètres d’interaction ainsi ajustés permettent une bonne restitution des données expérimentales. / Gasification of biomass is a promising thermochemical renewable energy resource. Among all biomass conversion processes, gasification by heat cogeneration / bio-SNG (Substitute Natural Gas) is the promising one. But still, one of the deadlocks to be raised is the reduction of the high level of tar present in the product gas. The objective of this work is to perform a data base which will be useful at the operation of tar removal from aqueous medium. The present work has mainly focused on the acquisition of bi and triphasic equilibrium data model molecules of tars - water - washing solvent. Such data are indeed essential for the development of the thermodynamic model for the modeling and the optimization of the washing process. Analyses of liquid phases in equilibrium have been performed by GC-FID or GC-MS. In some cases the concentration levels were particularly low (up to 10-10 mole fraction of anthracene in the aqueous phase). Reciprocal concentrations obtained and the partition coefficients which are deduced from the empirical correlation satisfy each of Hands and the Van't Hoff relationship. Liquid-liquid-vapor equilibrium of binary systems (water-extracting solvent) was studied with the static method. The concentrations of the phases in equilibrium were correlated by the NRTL and UNIQUAC models using the commercial software 'Thermodynamic Simulis'. The interaction parameters adjusted allow a good reproduction of experimental data.

Die experimentelle Charakterisierung von Phasengleichgewichten (Flüssigkeit-Dampf und Flüssigkeit-Flüssigkeit) erfolgte in binären und ternären Systemen aus aromatischen bzw. aliphatischen Kohlenwasserstoffen, Phenolen und Wasser. Die Trübungstitration diente der Bestimmung von Flüssigkeit-Flüssigkeit-Gleichgewichten, auftretende koexistierende flüssige Phasen wurden analytisch charakterisiert. Mit Hilfe der dynamischen Methode erfolgte die Bestimmung der Flüssigkeit-Dampf-Gleichgewichte. Die Modellierung der binären Systeme und die Vorausberechnung der ternären Systeme erfolgten mit den Aktivitätskoeffizientenmodellen NRTL und UNIQUAC. Weiterhin wurden die Berechnungen mit der von Elliott, Suresh und Donohue entwickelten Zustandsgleichung (ESD) durchgeführt, welche einen die assoziierenden Wechselwirkungen berücksichtigenden Term beinhaltet. Ferner wurden mit der Gruppenbeitragsmethode UNIFAC die untersuchten binären und ternären Systeme vorausberechnet. Beide Aktivitätskoeffizientenmodelle können bei der simultanen Modellierung der verfügbaren Phasengleichgewichtsdaten für nahezu alle betrachteten binären Systeme mit sehr guten Ergebnissen überzeugen. Bei der Modellierung mit der Zustandsgleichung ESD müssen deutlich höhere Abweichungen akzeptiert werden. Die Ergebnisse der Modellierung der binären Systeme lassen sich nicht adäquat auf die Vorausberechnung der ternären Systeme übertragen. UNIQUAC Modell und Zustandsgleichung ESD zeigen im Mittel die geringsten Unterschiede zwischen vorausberechneten und experimentellen Phasengleichgewichten. Deutlich höhere Abweichungen treten im Mittel bei Verwendung des NRTL Modells bzw. der Gruppenbeitragsmethode UNIFAC auf. Die Annahme, mit Hilfe der expliziten Berücksichtigung der Assoziation mit Zustandsgleichung ESD eine deutliche Verbesserung bei der Vorausberechnung entsprechender Phasengleichgewichten zu erzielen, konnte lediglich für Flüssigkeit-Flüssigkeit-Gleichgewichte in Systemen mit aliphatischen Kohlenwasserstoffen bestätigt werden. / The experimental characterizations of phase equilibria (vapor-liquid and liquid-liquid) were determined in binary and ternary systems containing aliphatic and aromatic hydrocarbons, phenols and water. Liquid-liquid equilibria were measured by turbidity titration. The compositions of coexisting phases were determined with analytic methods. The vapor-liquid equilibria were determined by the dynamic method. The correlation of the binary systems and the prediction of the ternary systems were performed with the activity coefficient models NRTL and UNIQUAC. Furthermore the calculations were realized with an equation of state (ESD) developed by Elliott, Suresh and Donohue, which contain a term for association. Additional predictions of investigated binary and ternary systems were performed with the group contribution method UNIFAC. Both activity coefficient models convinced with satisfactory results by the simultaneously correlation of the available equilibria data for almost all investigated binary systems. The correlations with the ESD equation of state were performed with higher deviations. A transfer of the results of the binary correlations into the ternary predictions is not possible. The UNIQUAC model and the ESD equation of state performed on average with minor deviations between predicted and experimental phase equilibria. Higher deviations were calculated using the NRTL model respectively the group contribution method UNIFAC. Only liquid-liquid equilibria in systems contain aliphatic hydrocarbons indicates improved prediction results based on the consideration of the association.

Die Phasengleichgewichte (Flüssigkeit-Dampf und Flüssigkeit-Flüssigkeit) der binären, ternären und quaternären Mischungen bestehend aus Wasser, Toluen, Anilin und Cyclohexylamin wurden experimentell bestimmt und modelliert bzw. vorausberechnet. Die Bestimmung der Flüssigkeit-Dampf-Gleichgewichte erfolgte mit Hilfe der dynamischen Methode, die dafür notwendige Mess- und Regeltechnik wurde erweitert und modernisiert. Die Flüssigkeit-Flüssigkeit-Gleichgewichte wurden durch Trübungstitration und Analyse der koexistierenden Phasen bestimmt. Die Beschreibung der binären Systeme und die Vorausberechnung der Mehrkomponentensysteme erfolgte mit den Aktivitätskoeffizientenmodellen UNIQUAC und NRTL und der Zustandsgleichung, entwickelt von Elliott, Suresh und Donohue (ESD). Die ESD-Zustandsgleichung enthält neben einem Attraktions- und einem Repulsionsterm auch einen Term, der assoziative Wechselwirkungen explizit berücksichtigt. Die Beschreibung der binären Systeme gelingt mit den getesteten Modellen sehr gut. Dabei werden mit den Aktivitätskoeffizientenmodellen bessere Ergebnisse erreicht als mit der ESD-Zustandsgleichung. Diese Bild kehrt sich bei der Vorausberechnung der Mehrkomponentensysteme um. Bei Verwendung der NRTL-Gleichung treten deutlich höhere Abweichungen auf als bei Berechnungen mit der ESD-Zustandsgleichung bzw. der UNIQUAC-Gleichung. Die Erwartung durch explizite Berücksichtigung der Assoziation mit der ESD-Zustandsgleichung einen deutlichen Vorteil in der Vorhersage von Phasengleichgewichten in Systemen mit assoziierenden Komponenten zu erhalten konnte in den untersuchten Mischungen nicht eindeutig bestätigt werden. / Phase equilibria (vapor-liquid and liquid-liquid) of binary, ternary and quaternary systems consisting of water, toluene, aniline and cyclohexylamine were determined experimentally and modeled resp. predicted. Vapor-liquid equilibria were determined by the dynamic method, the necessary measuring and control systems were extended and modernized. Liquid-liquid equilibria were investigated by turbidity titration and analyses of coexisting phases. The calculation of the binary systems and the prediction of the multicomponent systems were performed with the activity coefficient models UNIQUAC and NRTL and the equation of state developed by Elliott, Suresh and Donohue (ESD). The ESD equation of state includes beside an attractive and a repulsive term a term for explicit consideration of associative interaction. The description of the binary systems succeeded very well with the tested models. Better results were achieved with the activity coefficient models than with the ESD equation of state. These findings are inversed in the case of prediction of multicomponent phase equilibria. On application of the NRTL equation the deviations are notable greater than with the ESD equation of state or the UNIQUAC equation. The expectation to get a significant advantage in prediction of phase equilibria in systems with associating components with the ESD equation of state could not be answered definitely.

Le présent travail se propose de décrire les propriétés thermodynamiques des solutions d'intérêt industriel. Notre modèle s'appuie sur un travail antérieur (N. Papaiconomou et al.), combinant la théorie Mean Spherical Approximation (MSA) pour décrire les interactions électrostatiques à longue portée et le modèle NRTL (très populaire en génie chimique), pour celles qui sont à courte portée. Par rapport à ce précédent travail, nous avons de plus pris en compte l'effet de solvatation ionique, à l'aide de deux modèles différents : (a) celui de Stokes et Robinson impliquant un nombre de solvatation constant (en fonction de la concentration du sel) ; (b) une solution procédant d'équilibre réactionnels avec les molécules d'eau, résultant en un degré de solvatation variant avec la concentration de sel. De plus, nous avons cherché à décrire les équilibres L-V pour des solutions aqueuses et de mélanges de solvants, pour des températures allant de 25°C à 100°C.

Orientadores: Maria Regina Wolf Maciel, Martin Aznar / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-11T22:03:29Z (GMT). No. of bitstreams: 1 Machado_AlexBarreto_M.pdf: 1251594 bytes, checksum: 12614335c44f56e98288ed9de32033db (MD5) Previous issue date: 2007 / Resumo: Observa-se que, nos últimos anos, a procura por novos processos de separação para a recuperação de ácidos orgânicos, dentre eles o ácido acrílico, a partir de seu caldo de fermentação, tem sido intensa. O processo de extração líquido-líquido apresenta-se como uma alternativa das mais viáveis para sistemas diluídos, quando se utiliza solventes apropriados e de baixa toxicidade. Na parte computacional do trabalho em questão, inicialmente, realizou-se um estudo do software Aspen Plus no que se refere à obtenção de dados termodinâmicos (parâmetros binários) e curvas binodais. Realizou-se, também, a validação do software obtendo regressões de dados experimentais envolvendo fenol e alguns solventes retirados da literatura. Algumas curvas de extração (curvas binodais), testando diferentes solventes para extração do ácido acrílico, foram construídas. As curvas binodais simuladas no Aspen também auxiliaram na escolha dos pontos experimentais, uma vez que, desta maneira, já se conhecia a região de formação de duas fases dos sistemas em estudo e pôde-se orientar a coleta destes dados laboratoriais sem o consumo excessivo de reagentes e de tempo. A parte experimental deste projeto envolve a obtenção de dados de ELL dos sistemas ternários ácido acrílico - água e os seguintes solventes: diisopropil éter, isopropil acetato, 2-etil 1-hexanol, 4- metil 2-pentanona; além do levantamento dos dados de ELL dos sistemas quaternários: ácido acrílico+água+diisopropil éter+sal, usando como sais MgCl2 e CaCl2 de concentrações de 5 e 10%, respectivamente, e ácido acrílico+água+isopropil acetato+sal, usando como sais MgCl2 e CaCl2 de concentrações de 5 e 10% respectivamente. Os resultados encontrados foram muito satisfatórios, permitindo-se construir curvas de solubilidades e realizar as regressões utilizando os modelos de coeficiente de atividade UNIQUAC e NRTL, determinando-se os parâmetros binários. Foram realizadas comparações entre os 4 solventes de extração e entre os sistemas quaternários envolvendo sais. / Abstract: It is observed that, in the last years, the search for new separation processes for recovering organic acids, such as acrylic acid produced from renewable sugar, has been intense. The liquid-liquid extraction process appears as the most viable alternative for diluted systems, since suitable solvents are used. Related to the computational part of this work, initially, a study using the software Aspen Plus for obtaining thermodynamic data (binary parameters) and binodal curves were carried out. Some extraction curves (binodal curves), testing different solvents for acrylic acid extraction, were obtained. Binodal curves simulated with Aspen Plus were very important in choosing experimental points, since, in this way, it was possible to know the region where there are immiscible two phases and, so, to facilitate the obtention of experimental data without excessive consumption of reagents and time. In the experimental section of this work, experimental data of liquid liquid equilibria (LLE) were obtained for the ternary systems acrylic acid + water + solvents (diisopropyl ether, isopropyl acetate, 2-ethyll 1-hexanol, 4 - methyl 2-pentanona), beyond obtain LLE data for the quaternary systems acrylic acid + water + diisopropyl ether + salt (using MgCl2 or CaCl2, with concentrations of 5 and 10%, respectively) and system acrylic acid + water + isopropyl acetate + salt (using MgCl2 and CaCl2 with concentrations of 5 and 10%, respectively). The results obtained were very satisfactory. Experimental solubility curves and regressed curves, using UNIQUAC and NRTL models for the activity coefficient calculations, through the binary parameters, were carried out. The results obtained with four solvents were compared and the ternary and quaternary systems (involving salts) also were compared among themselves. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientadores: Eduardo Augusto Caldas Batista, Antonio Jose de Almeida Meirelles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T02:56:23Z (GMT). No. of bitstreams: 1 Priamo_WagnerLuiz_M.pdf: 1151319 bytes, checksum: 0c097b45fca5039b53924a7b27cd3e1a (MD5) Previous issue date: 2008 / Resumo: A extração de óleos vegetais com solvente possui a vantagem de operar a temperaturas menores em relação às usadas na extração mecânica, permitindo também a extração de outros compostos desejáveis da semente oleaginosa. Hexana é, geralmente, utilizada para extrair óleo por lixiviação, porém é inflamável e suspeita de causar danos à saúde humana. Alguns estudos surgiram com o intuito de investigar a mudança deste solvente. O processo de refino dos óleos vegetais brutos envolve a dessolventização, degomagem, branqueamento, desacidificação e desodorização. Óleos vegetais podem ser desacidificados por processos convencionais, como o refino químico e físico. O refino químico é aplicado para todos os óleos brutos, entretanto, proporciona grandes perdas de óleo neutro. Para óleo de alta acidez, o refino físico é também uma possibilidade, mas pode causar alterações indesejáveis na cor e na estabilidade oxidativa. Uma alternativa é a desacidificação por extração líquido-líquido, o qual é um processo mais brando, ocorrendo à temperatura ambiente e pressão atmosférica, causando menores perda de óleo neutro. Ainda, destaca-se a produção de biodiesel a partir de matrizes vegetais, onde este pode ser produzido pela transesterificação de triacilgliceróis com metanol ou etanol gerando metil ou etil ésteres. A baixa solubilidade dos triacilgliceróis em álcoois aponta para a necessidade do uso de outros solventes que proporcionem um sistema monofásico e melhorar a difusão dos reagentes. O conhecimento do comportamento de fases destes sistemas compostos por óleo vegetal bruto/solventes à diferentes temperaturas, configura o principal tópico em operações de transferência de massa e catálise. Levando isto em consideração, este trabalho teve por objetivo determinar experimentalmente dados de equilíbrio líquido-líquido de sistemas ternários compostos por óleo de farelo de arroz refinado/etanol anidro/n-hexano e quaternários compostos por óleo de farelo de arroz refinado/ácido oléico comercial/etanol anidro/n-hexano, usando a técnica de espectroscopia por infravermelho próximo para a quantificação dos componentes das fases em equilíbrio. A partir dos resultados obtidos, verificou-se que a solubilidade dos sistemas é afetada pelo teor de ácido graxo livre presente no óleo de farelo de arroz, onde com o aumento deste acarreta numa diminuição da região heterogênea. O mesmo fato ocorreu no estudo realizado para os sistemas ternários, onde o aumento da temperatura promoveu um aumento da solubilidade, devido ao fato de a solubilidade mútua entre o óleo de farelo de arroz e etanol aumentar com o aumento desta variável. Em todos os sistemas, verificaram-se maiores desvios no balanço de massa para o componente ácido oléico comercial e n-hexano, enquanto que para os demais componentes, óleo de farelo de arroz e etanol anidro, seus desvios foram baixos. Através dos dados obtidos nesse trabalho verificou-se que o método proposto pode ser utilizado na quantificação dos componentes nas fases em equilíbrio para sistemas ternários e quaternários apresentando algumas vantagens em relação a outras técnicas, como por exemplo, a cromatografia. Os dados de equilíbrio líquido-líquido foram usados para ajustar os parâmetros do modelo de NRTL, com desvio médio relativo de 1,06 % para os sistemas a 25 ºC e de 0,26 % para o sistema ternário a 40 ºC / Abstract: Solvent extraction has the advantage of operating at lower temperatures and also can extract other desirable components from oilseeds when compared to mechanical extraction. Commercial hexane is the usual solvent to extract oil by leaching, but it is highly flammable and it can cause hazard to human health. Some studies have begun to investigate the change of this solvent. The refining processes of crude vegetable oils involve solvent stripping, degumming, bleaching, deacidification and deodorization. Vegetable oils can be deacidified by conventional processes, such as chemical and physical refining. Chemical refining is applicable for all raw materials; however, it can result in large losses of neutral oil. For high acidity oils, physical refining is also a possibility, but can cause undesirable alterations in color and stability to oxidation. An alternative is the deacidification by liquid-liquid extraction, process carried out at room temperature and atmospheric pressure and that causes lower loss of neutral oil. Biodiesel is a renewable energetic source and it is gaining acceptance and market. The most common way to produce biodiesel is by transesterification of triacylglycerols with methanol or ethanol, generating methyl or ethyl esters. The low solubility of triacylglycerols in alcohols presents the necessity of using some another solvent to create a system of one phase and to improve the diffusion of the reagents. The knowledge of the behavior of all these systems of crude vegetable oil / solvents at different temperatures configures the principal topic in mass transfer operations and catalysis. Taking, these points into account, this work aims to determine experimental data for liquid-liquid equilibrium of ternary systems containing refined rice brain oil / anhydrous ethanol / n-hexane and quaternary systems containing refined rice brain oil / commercial oleic acid / anhydrous ethanol / n-hexane, using Near Infrared Spectroscopy (NIR) for quantification of the components in each phase in equilibrium. For the quaternary systems, the increasing in the oleic acid composition in rice brain oil increases the solubility of the systems and decreases the biphasic region. For the ternary systems, the results showed that the increase in the temperature promotes a reduction of the two phase region, given by the increase of the mutual solubility of refined rice brain oil and anhydrous ethanol. In all systems higher deviations of mass balance for the commercial oleic acid and hexane were found, while for the other components, refined rice brain oil and anhydrous ethanol, the deviations were lower. According to the results obtained, we concluded that the Near Infrared Spectroscopy is highly accurate, with some advantage in relation to other analytical methods. The experimental data were correlated using the NRTL model, and for the systems at 298.3 K, the global deviation was 1.06 %; for the ternary system at 313.3 K, the global deviation was 0.26 % / Mestrado / Mestre em Engenharia de Alimentos

Orientador: Eduardo Augusto Caldas Batista / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-12T23:16:20Z (GMT). No. of bitstreams: 1 Dalmolin_IredeAngelaLucini_M.pdf: 1335976 bytes, checksum: d9b7b355cbf37e6ff34460cbdc41bfd5 (MD5) Previous issue date: 2009 / Resumo: A extração do óleo do farelo agrega valor à produção de arroz. Este óleo possui propriedades nutricionais e nutracêuticas, portanto, o interesse de indústrias em seu uso. A desacidificação do óleo pode ser realizada por extração líquido¿líquido com baixas perdas de óleo neutro, principalmente no caso de óleo com alto conteúdo de ácidos graxos livres. Nestes processos, um solvente parcialmente miscível, como etanol ou etanol hidratado, é utilizado para extrair os ácidos graxos livres do óleo bruto. Por outro lado, questões ambientais e energéticas têm voltado à atenção para o uso de óleos vegetais na produção de biodiesel por reação de transesterificação. O conhecimento do equilíbrio líquido¿líquido como de sistemas graxos é uma importante etapa na otimização da produção de óleo comestível por extração líquido¿líquido ou de produção de biodiesel por reação de transesterificação. Deste modo, este trabalho teve por objetivo determinar experimentalmente dados de equilíbrio líquido-líquido de sistemas compostos por óleo de farelo de arroz refinado / etanol anidro / água / hexano a (25 e 40) ºC e ajustar os parâmetros do modelo NRTL aos dados experimentais. A técnica de espectroscopia no infravermelho próximo (NIR) foi utilizada para quantificar os componentes nas fases. Para evitar a separação de fases na amostragem dos sistemas a 40 ºC, a diluição com tetrahidrofurano das amostras das fases foi investigada. Todos os sistemas estudados neste trabalho apresentaram desvios de balanço de massa global menores que 0,5 %, e desvios na correlação pelo modelo NRTL menores que 1,0 %. Estes resultados indicam a boa qualidade dos dados experimentais e que a técnica de espectroscopia no NIR fornece bons resultados mesmo quando os componentes estão em pequeno conteúdo na mistura / Abstract: The extraction of oil from rice bran aggregates value to the rice production. This oil has nutritional and nutraceutical properties, therefore, the interest of the industries in its use. The oil deacidification can be carried out by liquid¿liquid extraction with lower loss of neutral oil, mainly in the case of oil with high content of free fatty acid. In this process, a partially miscible solvent, such as ethanol or hydrated ethanol, is used to extract the free fatty acids from crude oils. Moreover, environmental and energy issues have focused attention to the use of vegetable oils in biodiesel production by transesterification reaction. The knowledge of the liquid¿liquid equilibrium of such fatty systems is an important stage in the optimization of the production of edible oil by liquid¿liquid extraction or the production of biodiesel by transesterification reaction. Thus, this work aims to determine experimental data from liquid-liquid equilibrium of systems containing refined rice bran oil / anhydrous ethanol / water / hexane at (298.15 and 313.15) K and to adjust the parameters of NRTL model to the experimental data. The technique of near infrared spectroscopy (NIR) was use to quantify the components in the phases. To avoid phase separation in sampling for system at 313.15 K, the dilution of the phases with tetrahydrofuran was investigate. All systems studied in this work presented overall mass balance deviations lower than 0.5 % and deviations in correlation by NRTL model lower than 1.0 %. These results indicate the good quality of the experimental data and that the NIR gives good results even when the components are in low content in the mixture / Mestrado / Mestre em Engenharia de Alimentos