La distillation dite « charentaise » est une méthode de distillation discontinue permettant la production d’eaux-de-vie de cognac à partir de vin. La distillation est effectuée dans des alambics en cuivre avec un chauffage à feu nu qui peut être favorable à la génération de composés volatils. Or, les précurseurs et les mécanismes de réactions formant ces composés, pendant la distillation, restent mal connus. La première partie de l’étude consiste à identifier les composés volatils formés au cours de la distillation charentaise. Le bilan matière effectué sur de nombreux composés lors du procédé de distillation a révélé que 2 esters, 3 aldéhydes, 3 terpènes et 12 norisoprénoïdes étaient générés. Par la suite, deux distillations utilisant un mode de chauffe différent (feu nu et vapeur) ont été menées sur un alambic pilote. Le but était d’évaluer l’impact du mode de chauffe sur la génération en composés volatils. L’étude a montré que le mode de chauffe a peu d’effet sur la génération en composés volatils. De plus, les composés formés sont similaires à ceux formés lors de la distillation en alambic traditionnel. Enfin, le troisième axe de l’étude porte sur la caractérisation de l’hydrolyse acide de l’α- terpenyl-O-β-glucopyranoside, précurseur impliqué dans la formation de l’α-terpineol, identifié comme étant généré lors de la distillation charentaise ainsi qu’en alambic pilote. Le suivi de la dégradation dans un réacteur hermétiquement fermé de l’α-terpenyl-O-β-glucopyranoside et dans des conditions représentatives du vin durant la distillation montre l’hydrolyse pour former l’α- terpineol, le trans-terpin et son isomère. Cette étude a révélé que l’hydrolyse du précurseur est favorisée en milieu aqueux et suit une cinétique d’ordre 1 / The « charentaise » distillation is a batch distillation method that allows the production of cognac spirits from wine. The distillation is performed in copper alembics through a direct open flame heating that could favor the formation of volatile compounds. The first part of this study consists in identifying the volatile compounds formed during the distillation of cognac spirits. The mass balance performed on volatile compounds revealed that 2 esters, 3 aldehydes, 3 terpenes and 12 norisoprenoids were generated. Thereafter, two distillations using a different heating mode (direct open flame and steam) were conducted on a small-scale alembic. The goal was to assess the impact of the heating mode on the formation of volatile compounds. The study showed that the mode of heating has little effect on volatile compounds’ generation. Moreover, the compounds formed are similar to the ones during the traditional distillation of cognac spirit. Finally, the third part of the study focuses on the characterization of the acid hydrolysis of α-terpenyl-O-β-glucopyranoside which is the suspected precursor to be involved in the formation of α-terpineol, identified as generated during the charentaise distillation and in small-scale distillations. α-terpenyl-O-β- glucopyranoside was placed in two representative model solutions corresponding to the initial wine and the stillage. Both solutions were exposed to 100 °C in a closed reactor system. Results showed that the hydrolysis of the precurseur formed α- terpineol, trans-terpin and its isomere that seems to be 4-(2-hydroxypropan-2-yl)-1- methylcyclohexan-2-ol). Data also revealed that the hydrolysis of the precursor follows a first order reaction model ant that an aqueous media promotes the formation of trans-terpin.

The increasing trend of world-wide energy consumption emphasizes the importance of ongoing optimization of new and existing technologies. In this dissertation, two energy–intensive systems are simulated and optimized. Advanced estimation, optimization, and control techniques such as a moving horizon estimator and a model predictive controller are developed to enhance the profitability, product quality, and reliability of the systems. An enabling development is presented for the solution of complex dynamic optimization problems. The strategy involves an initialization approach to large–scale system models that both enhance the computational performance as well as the ability of the solver to converge to an optimal solution. One particular application of this approach is the modeling and optimization of a batch distillation column. For estimation of unknown parameters, an L1-norm method is utilized that is less sensitive to outliers than a squared error objective. The results obtained from the simple model match the experimental data and model prediction for a more rigorous model. A nonlinear statistical analysis and a sensitivity analysis are also implemented to verify the reliability of the estimated parameters. The reduced–order model developed for the batch distillation column is computationally fast and reasonably accurate and is applicable for real time control and online optimization purposes. Similar to estimation, an L1-norm objective function is applied for optimization of the column operation. Application of an L1-norm permits explicit prioritization of the multi–objective problems and adds only linear terms to the problem. Dynamic optimization of the column results in a 14% increase in the methanol product obtained from the column with 99% purity. In a second application of the methodology, the results obtained from optimization of the hybrid system of a cryogenic carbon capture (CCC) and power generation units are presented. Cryogenic carbon capture is a novel technology for CO2 removal from power generation units and has superior features such as low energy consumption, large–scale energy storage, and fast response to fluctuations in electricity demand. Grid–level energy storage of the CCC process enables 100% utilization of renewable power sources while 99% of the CO2 produced from fossil–fueled power plants is captured. In addition, energy demand of the CCC process is effectively managed by deploying the energy storage capability of this process. By exploiting time–of–day pricing, the profit obtained from dynamic optimization of this hybrid energy system offsets a significant fraction of the cost of construction of the cryogenic carbon capture plant.

La tesis doctoral se compone de dos partes fundamentales: El desarrollo teórico de un modelo de simulación para la destilación discontinua y la validación de este mediante experimentos hechos en una planta piloto de destilación discontinua. La parte teórica se divide en la parte de desarrollo del modelo y en la parte de la implementación del modelo en un programa de simulación. El nuevo modelo desarrollado es un modelo de transferencia de materia que se distingue de los desarrollos anteriores por su capacidad de contemplar la cinética de la transferencia de materia tal como la hidrodinámica. La incorporación de efectos hidrodinámicos se basa principalmente en la observación de diferentes geometrías de contacto en una columna de platos perforados. Estas geometrías de contacto son canales de vapor y burbujas. En caso de las burbujas se distingue entre grandes y pequeñas con diferentes propiedades hidrodinámicas. De esta forma el modelo contempla tres diferentes clases de vapor, dos clases de vapor de desequilibrio y una de equilibrio (burbujas pequeñas). Para las clases de vapor de desequilibrio se calcula explícitamente los caudales de materia que traviesen la interfase basándose en la teoría de Maxwell-Stefan de transferencia de materia multicomponente. La parte experimental se divide en la parte de diseño de la columna usada en una planta piloto y en la de la realización de los experimentos. El diseño de la columna tiene como objetivo la obtención de un medio de validación del nuevo modelo desarrollado. Por tanto está equipado con un gran número de sensores de temperatura, de presión y de tomas de muestra. También la realización de los experimentos se adapta al fin de la validación del modelo, ya que la frecuencia de toma de muestra y de capturación de señales de temperatura es elevada. La memoria de la tesis contiene una comparación amplia de los resultados experimentales con los de la simulación. Estas comparaciones demuestran una determinada superioridad del modelo desarrollado sobre desarrollos anteriores.

During the last decades, batch distillation is preferably used with an increasing demand over continuous one, to separate fine chemicals in chemical and petroleum industries, due to its advantages like, flexibility and high product purity. Consequently, packed distillation columns, with newly generated packing materials, are advantageous compared to plate columns because of their smaller holdups, resistivity to corrosive materials and their higher separation efficiencies. Also, in many industrial applications, mathematical models of distillation systems are frequently used in order to design effective control systems, to train operating personnel and to handle fault diagnostics. Thus, the main objective of this study is to develop a mathematical model for a multicomponent batch distillation column, which is used to separate mixtures at low operating pressures, packed with random packing materials. In multicomponent batch packed distillation, operation with optimum reflux ratio profile is important for efficiency to maximize the amount of the distillate with a specified concentration, for a given time. Therefore, it is also aimed to find the optimum reflux ratio profile for the multicomponent batch packed distillation column. A simulation algorithm is written with the aid of MATLAB and FORTRAN programming languages by taking into account pressure drop and variation of physical properties. The selected incremental bed height, &amp / #916 / z, to be used in the simulation program has an effect on the accuracy of the results. This is analyzed and the optimal incremental height is found to be 3.5 cm for a 1.5m bed height. The change in distillate compositions with a given constant reflux ratio is found to be similar with those of previous studies. The simulation code is also used to obtain responses in distillate compositions for different reflux ratios, condenser holdups and reboiler duties and compared with similar studies found from literature and found to be adequate. Finally, experiments are conducted to verify simulation algorithm by using a lab-scale packed distillation column for the separation of a polar mixture of ethanol and water. It is observed that, there is a good agreement between the experimental and simulation results. After the verification of dynamic model, optimum operation policy to maximize product amount is investigated numerically by using capacity factor approach. The column is operated with and without recycling of the holdups of the slop cut tanks, in order to examine the effect of recycling on capacity factor, CAP. It is observed that, recycling of the molar holdups of the slop cut tanks is resulted in a 28% increase in the separation efficiency.

In the control of batch and continuous distillation columns, one of the most challenging problem is the difficulty in measuring compositions. This problem can be handled by estimating the compositions from readily available online temperature measurements using a state observer. The aim of this study is to design a state observer that estimates the product composition in a multicomponent batch distillation column (MBDC) from the temperature measurements and to test this observer using a batch column simulation. To achieve this, first a model for MBDC is prepared and compared with the data from literature where a case column is utilized. After checking the validity of the simulation package, it is used as a fictitious process for the performance evaluations. In the second phase of the study, an extended Kalman Filter (EKF) is designed by utilizing a simplified model of MBDC and it is implemented for performance investigation on the case column with 8 trays separating the mixture of cyclohexane, n-heptane and toluene. The simplified model utilized in EKF results in response, which have some deviation with rigorous model, mainly due to the simplification of vapor-liquid equilibrium relationship. In the performance evaluation, the tuning parameters of EKF / the diagonal terms of process noise covariance matrix and the diagonal terms of measurement model noise covariance matrix are changed in the range of 50&iexcl / 1x10&iexcl / 7 and 0:5&iexcl / 5x108 and the optimum values are found as 0:00001 and 5000, respectively. The effect of number of measurement points is also investigated with a result of number of component measurements. The effect of measurement period value is also studied and found that it has a major effect on the performance which has to be determined by the available computational facilities. The control of the column is done by utilizing the designed EKF estimator and the estimator is successfully used in controlling the product purities in MBDC under variable reflux-ratio operation.

Este trabalho tem por objetivo comparar dois modos de operação de destilação em batelada: com refluxo constante e composição do destilado constante. Desenvolveuse um modelo matemático para a destilação em batelada de uma mistura binária (metanol-etanol) para operação com cada um destes modos. O modelo consiste basicamente dos balanços de massa e entalpia, relações e diagramas de equilíbrio líquido-vapor (composição de equilíbrio, temperaturas de bolha e orvalho da mistura), estimativa das propriedades físico-químicas da mistura (calor específico, calor latente de vaporização), determinação do número de estágios ideais necessários à separação (pelo método de McCabe-Thiele), cálculo de cargas térmicas no refervedor e condensador, consumo de utilidades (vapor de água e água de resfriamento), estimativa do tempo de destilação e alguns aspectos econômicos sobre o processo (custos de equipamentos e operacionais, capacidade de produção, lucro mensal). Implementou-se em uma planilha eletrônica este modelo para as simulações matemáticas e análise técnico-econômica do processo. Em escala de laboratório (foram realizados, ao todo, oito ensaios, quatro de refluxo constante e quatro de refluxo variável, utilizando uma coluna de pratos perfurados), constatou-se uma boa concordância entre estes resultados experimentais e os calculados a partir da modelagem. Em seguida, estudaram-se, isoladamente em cada modo de operação e de modo comparativo, as principais variáveis de processo (taxa de refluxo, composição do destilado, quantidade de carga, vazão de destilado, etc.) através de simulações matemáticas, tanto no cenário de uma unidade existente como no caso do projeto de uma instalação nova. Para uma instalação existente, verificou-se, que no modo de destilação com composição de destilado constante, mantendo-se a vazão do vapor de topo constante, o tempo de destilação é menor, a capacidade de destilação é maior, resultando em maior lucro mensal. Para uma instalação a ser projetada, de novo, o processo mais vantajoso é o de refluxo variável e vazão de vapor do topo constante, pois requer menores áreas dos trocadores de calor para uma dada separação num tempo fixo de processo. No entanto, para o processamento de uma dada quantidade num mesmo tempo, à medida que se adota, no projeto, um número maior de estágios de separação na coluna, a diferença de lucro mensal torna-se praticamente indistinta para os modos de destilação estudados. / The aim of this study is to compare two operational methods of batch distillation of a binary system (methanolethanol): constant reflux and constant distillate composition. A phenomenological modeling concerning each mode was developed. It was based on material and enthalpy balances, equilibrium relationships, estimation of physical properties (specific heat and latent vaporization heat of mixtures), determination of ideal stages number (using McCabe-Thiele method), calculation of rebolier and condenser thermal loads and areas, steam and cooling water requirement, distillation time and some economical aspects. The mathematical model was implemented into an electronic spreadsheet. The predicted values were compared to experimental results from eight tests carried out in a laboratory sieve tray column (four at constant reflux and four at constant distillate composition), and a good consistency was found. Then several case studies concerning each distillation mode as well as the comparative performance were accomplished through mathematical simulations. Evaluation of the basic process variables such as reflux rate, initial load, distillate composition and flow rate was done. Rating of an existing plant and design of a new installation were considered in this process analysis. For an existing installation, lower distillation time, as well as higher distillation capacity and monthly profit were observed when distilling with constant distillate composition, keeping constant the flow rate of vapor from the column top. This process is also the more advantageous one when designing a new plant since smaller heat exchanger areas are required. However, to process a quantity in a same time, in a design of a new plan, as number of separation stages increases, monthly profit becomes almost the same among the studied distillation modes.

Yes / The formation of methyl decanoate (MeDC) by esterification reaction of decanoic acid with methanol through batch/continuous reactive distillation columns is operationally challenging, energy intensive and thus cost intensive operation due to complex thermodynamic behaviour of the reaction scheme. Aiming to overcome the equilibrium restriction of the decanoic acid (DeC) esterification operation, to improve the process efficiency and to reduce the total annualised cost (TAC), the semi-batch distillation column (SBD) and the recently proposed integrated semi-batch distillation column configuration (i-SBD) are investigated here. The performances of each of these column operations are evaluated in terms of minimum TAC for a given separation task. In both column configurations, additional operating constraints are considered into the optimization problem to prevent flooding of still pot due to the continuous charging of methanol into it. This study shows the superiority of i-SBD mode of operation over SBD operation in terms of TAC. Also, the optimization results for a defined separation task indicate that the performance of multi-interval control policy is overwhelmingly superior to the single-interval control operation in terms of operating batch time, and overall annual cost in the i-SBD system providing about a time saving of 82.75%, and cost (TAC) saving of 36.61% for a MeDC (product) concentration of 0.945 molefraction.

A grande dificuldade na simulação de processos envolvendo substâncias naturais é o reduzido número de propriedades termo físicas e dados experimentais disponível na literatura. Devido à diversidade e complexidade das moléculas presentes, o estudo do processamento de compostos naturais ainda é pequeno. Neste trabalho, são investigados modelos para predição de tais propriedades termodinâmicas, fundamentais à modelagem e simulação do processo de destilação em batelada de óleos essenciais. Um método de contribuição de grupos é utilizado para predição da pressão de vapor de substâncias puras (CSGC-PVR), quando dados experimentais não são disponíveis. Em relação ao cálculo do coeficiente de atividade, um modelo totalmente preditivo baseado em química quântica computacional é utilizado (COSMO-SAC). De modo geral, este trabalho tem como objetivo a aplicação de propriedades termodinâmicas preditas em um modelo dinâmico, capaz de descrever o processo de retificação através da destilação em batelada. As simulações foram realizadas no simulador orientado a equações EMSO, a fim de demonstrar a viabilidade do método. Os óleos essenciais de Eucalyptus globulus Labill, Eucalyptus citriodora Hook e Cymbopogon winterianus Jowitt foram selecionados devido ao potencial econômico de suas frações. Inicialmente, um conjunto de dados experimentais é comparado às simulações para validação do método. Em um segundo momento, as simulações são realizadas para correlacionar as condições operacionais e cortes de destilado para as misturas dadas. Os perfis de composição e a determinação dos cortes majoritários são apresentados. Duas alternativas são avaliadas para obtenção de maior pureza nos cortes; o uso de bateladas de reciclo e o controle da razão de refluxo através de uma ação proporcional. A influência de diferentes configurações de coluna também é avaliada, variando o número de estágios teóricos, regime de refluxo e acúmulo de coluna. Os métodos utilizados se mostram capazes de predizer o comportamento do processo de fracionamento e podem ser aplicados a um grande número de óleos essenciais. / The great obstacle in simulating processes involving natural products is the small number of thermo-physical properties and experimental data available in the literature. Due to the diversity and complexity of these molecules, studies concerning essential oils processing is still limited. In this work, thermodynamic models are investigated in order to predict such properties, which are requisites to the modelling and simulation of the essential oil batch distillation process. In this work a group contribution method is used to predict the vapor pressure (CSGC-PVR) when experimental data was unavailable. Regarding the activity coefficients, a fully predictive model based on quantum calculations (COSMO-SAC) is used. Moreover, this work also aims the use of those predicted properties in a dynamic model, capable of describing the fractionation process by batch distillation. The simulations were performed in the equation-oriented simulator EMSO, in order to demonstrate the feasibility of the method. Oils of Eucalyptus globulus Labill, Eucalyptus citriodora Hook and Cymbopogon winterianus Jowitt were selected due to their high production and economic potential of its fractions. Initially, a set of experimental data is compared to the simulations in order to validate the method. Then, simulations are performed to relate operational conditions and distillate cuts for the given mixtures. The distillate composition profiles and the determination of the major cuts are presented. Two alternatives are evaluated in order to obtain cuts of higher purity; the use of a recycle batch and a reflux ratio proportional control based on the distillate composition. The influence of different column configurations is also evaluated, varying its number of theoretical stages, reflux ratio regime and column holdup. The methods used are shown able to predict a reasonable behavior for the fractionation process of the essential oils tested and the method can be extended to most of the essential oils.

A grande dificuldade na simulação de processos envolvendo substâncias naturais é o reduzido número de propriedades termo físicas e dados experimentais disponível na literatura. Devido à diversidade e complexidade das moléculas presentes, o estudo do processamento de compostos naturais ainda é pequeno. Neste trabalho, são investigados modelos para predição de tais propriedades termodinâmicas, fundamentais à modelagem e simulação do processo de destilação em batelada de óleos essenciais. Um método de contribuição de grupos é utilizado para predição da pressão de vapor de substâncias puras (CSGC-PVR), quando dados experimentais não são disponíveis. Em relação ao cálculo do coeficiente de atividade, um modelo totalmente preditivo baseado em química quântica computacional é utilizado (COSMO-SAC). De modo geral, este trabalho tem como objetivo a aplicação de propriedades termodinâmicas preditas em um modelo dinâmico, capaz de descrever o processo de retificação através da destilação em batelada. As simulações foram realizadas no simulador orientado a equações EMSO, a fim de demonstrar a viabilidade do método. Os óleos essenciais de Eucalyptus globulus Labill, Eucalyptus citriodora Hook e Cymbopogon winterianus Jowitt foram selecionados devido ao potencial econômico de suas frações. Inicialmente, um conjunto de dados experimentais é comparado às simulações para validação do método. Em um segundo momento, as simulações são realizadas para correlacionar as condições operacionais e cortes de destilado para as misturas dadas. Os perfis de composição e a determinação dos cortes majoritários são apresentados. Duas alternativas são avaliadas para obtenção de maior pureza nos cortes; o uso de bateladas de reciclo e o controle da razão de refluxo através de uma ação proporcional. A influência de diferentes configurações de coluna também é avaliada, variando o número de estágios teóricos, regime de refluxo e acúmulo de coluna. Os métodos utilizados se mostram capazes de predizer o comportamento do processo de fracionamento e podem ser aplicados a um grande número de óleos essenciais. / The great obstacle in simulating processes involving natural products is the small number of thermo-physical properties and experimental data available in the literature. Due to the diversity and complexity of these molecules, studies concerning essential oils processing is still limited. In this work, thermodynamic models are investigated in order to predict such properties, which are requisites to the modelling and simulation of the essential oil batch distillation process. In this work a group contribution method is used to predict the vapor pressure (CSGC-PVR) when experimental data was unavailable. Regarding the activity coefficients, a fully predictive model based on quantum calculations (COSMO-SAC) is used. Moreover, this work also aims the use of those predicted properties in a dynamic model, capable of describing the fractionation process by batch distillation. The simulations were performed in the equation-oriented simulator EMSO, in order to demonstrate the feasibility of the method. Oils of Eucalyptus globulus Labill, Eucalyptus citriodora Hook and Cymbopogon winterianus Jowitt were selected due to their high production and economic potential of its fractions. Initially, a set of experimental data is compared to the simulations in order to validate the method. Then, simulations are performed to relate operational conditions and distillate cuts for the given mixtures. The distillate composition profiles and the determination of the major cuts are presented. Two alternatives are evaluated in order to obtain cuts of higher purity; the use of a recycle batch and a reflux ratio proportional control based on the distillate composition. The influence of different column configurations is also evaluated, varying its number of theoretical stages, reflux ratio regime and column holdup. The methods used are shown able to predict a reasonable behavior for the fractionation process of the essential oils tested and the method can be extended to most of the essential oils.

A grande dificuldade na simulação de processos envolvendo substâncias naturais é o reduzido número de propriedades termo físicas e dados experimentais disponível na literatura. Devido à diversidade e complexidade das moléculas presentes, o estudo do processamento de compostos naturais ainda é pequeno. Neste trabalho, são investigados modelos para predição de tais propriedades termodinâmicas, fundamentais à modelagem e simulação do processo de destilação em batelada de óleos essenciais. Um método de contribuição de grupos é utilizado para predição da pressão de vapor de substâncias puras (CSGC-PVR), quando dados experimentais não são disponíveis. Em relação ao cálculo do coeficiente de atividade, um modelo totalmente preditivo baseado em química quântica computacional é utilizado (COSMO-SAC). De modo geral, este trabalho tem como objetivo a aplicação de propriedades termodinâmicas preditas em um modelo dinâmico, capaz de descrever o processo de retificação através da destilação em batelada. As simulações foram realizadas no simulador orientado a equações EMSO, a fim de demonstrar a viabilidade do método. Os óleos essenciais de Eucalyptus globulus Labill, Eucalyptus citriodora Hook e Cymbopogon winterianus Jowitt foram selecionados devido ao potencial econômico de suas frações. Inicialmente, um conjunto de dados experimentais é comparado às simulações para validação do método. Em um segundo momento, as simulações são realizadas para correlacionar as condições operacionais e cortes de destilado para as misturas dadas. Os perfis de composição e a determinação dos cortes majoritários são apresentados. Duas alternativas são avaliadas para obtenção de maior pureza nos cortes; o uso de bateladas de reciclo e o controle da razão de refluxo através de uma ação proporcional. A influência de diferentes configurações de coluna também é avaliada, variando o número de estágios teóricos, regime de refluxo e acúmulo de coluna. Os métodos utilizados se mostram capazes de predizer o comportamento do processo de fracionamento e podem ser aplicados a um grande número de óleos essenciais. / The great obstacle in simulating processes involving natural products is the small number of thermo-physical properties and experimental data available in the literature. Due to the diversity and complexity of these molecules, studies concerning essential oils processing is still limited. In this work, thermodynamic models are investigated in order to predict such properties, which are requisites to the modelling and simulation of the essential oil batch distillation process. In this work a group contribution method is used to predict the vapor pressure (CSGC-PVR) when experimental data was unavailable. Regarding the activity coefficients, a fully predictive model based on quantum calculations (COSMO-SAC) is used. Moreover, this work also aims the use of those predicted properties in a dynamic model, capable of describing the fractionation process by batch distillation. The simulations were performed in the equation-oriented simulator EMSO, in order to demonstrate the feasibility of the method. Oils of Eucalyptus globulus Labill, Eucalyptus citriodora Hook and Cymbopogon winterianus Jowitt were selected due to their high production and economic potential of its fractions. Initially, a set of experimental data is compared to the simulations in order to validate the method. Then, simulations are performed to relate operational conditions and distillate cuts for the given mixtures. The distillate composition profiles and the determination of the major cuts are presented. Two alternatives are evaluated in order to obtain cuts of higher purity; the use of a recycle batch and a reflux ratio proportional control based on the distillate composition. The influence of different column configurations is also evaluated, varying its number of theoretical stages, reflux ratio regime and column holdup. The methods used are shown able to predict a reasonable behavior for the fractionation process of the essential oils tested and the method can be extended to most of the essential oils.