No / In this work, energy consumption in a middle vessel batch reactive distillation (MVBRD) column is considered for the production of lactic acid via hydrolysis of methyl lactate. A dynamic optimization problem incorporating a process model is formulated to minimize the batch time which consequently minimizes the total energy consumption. The problem is subject to constraints on the amount and purity of lactic acid. The optimisation variables are reflux ratio and/or reboil ratio which are treated as piecewise constant. The earlier work of the authors on energy consumption in conventional batch reactive distillation column (CBRD) for the same reaction system is used for comparative analysis with the energy consumption in MVBRD. As an example, for a given separation task, the optimization results show that MVBRD is capable of saving over 23 % energy compared to energy consumption in CBRD column for the same task.

The synthesis of a number of alkyl esters such as methyl lactate, methyl decanoate, and ethyl benzoate via esterification in a reactive distillation is quite challenging. It is due to the complexity in the thermodynamic behaviour of the chemical species in the reaction mixture in addition to the difficulty of keeping the reactants together in the reaction section. One of the reactants (in these esterification reactions) having the lowest boiling point can separate from the other reactant as the distillation continues. This can result in a significant drop in the reaction conversion in a conventional reactive distillation whether it is a batch or a continuous column. To overcome this challenge, new different types of batch reactive distillation column configurations: (1) integrated conventional (2) semi-batch (3) integrated semi-batch (4) integrated dividing-wall batch distillation columns have been proposed here. Four esterification reaction schemes such as (a) esterification of lactic acid (b) esterification of decanoic acid (c) esterification of benzoic acid (d) esterification of acetic acid are investigated here. A detailed dynamic model based on mass, energy balances, chemical reaction, and rigorous thermodynamic (chemical and physical) properties is considered and incorporated in the optimisation framework within gPROMS (general PROcess Modelling System) software. It is found that for the methyl lactate system, the i-SBD operation outperforms the classical batch operations (CBD or SBD columns) to satisfy the product constraints. While, for the methyl decanoate system, the i-DWCBD operation outperforms all CBD, DWBD and sr-DWBD configurations by achieving the higher reaction conversion and the maximum product purity. For the ethyl benzoate system, the performance of i-CBD column is superior to the CBD process in terms of product quality, and conversion rate of acid. The CBD process is found to be a more attractive in terms of operating time saving, and annual profit improvement compared to the IBD, and MVD processes for the benzyl acetate system. / The Higher Committee for Education Development in Iraq (HCED)

Foi realizado um estudo de desenvolvimento de projeto conceitual de uma unidade produtora de triacetina a partir de glicerol, como forma de aumentar a viabilidade de produção de biodiesel. A esterificação de glicerol com ácido acético envolve três reações de acetilação reversíveis consecutivas. Em cada etapa, água é produzida, resultando em conversão limitada e baixa seletividade. Uma forma de aumentar a seletividade da triacetina consiste em remover continuamente a água do meio reacional, de modo a alterar o equilíbrio. Foram considerados dois processos baseados em cinéticas diferentes. O processo A proposto baseia-se no sistema reacional descrito por Mufrodi et al. (2012), que emprega ácido sulfúrico como catalisador e o processo B baseia-se no sistema descrito por Galan et al. (2009), que consiste na esterificação de glicerol utilizando ácido acético em excesso como catalisador. Os dois processos foram simulados usando uma coluna de destilação reativa com hexano como potencializador do arraste de água, e diferentes configurações foram estudadas usando o simulador Aspen Plus®. As especificações do processo conceitual de uma unidade industrial otimizada, capaz de processar o glicerol produzido em uma unidade típica produtora de biodiesel, foram estimadas para os dois processos em termos de mínimo consumo específico de energia e produção de triacetina de pureza molar de 99,9%, com conversão completa de glicerol. O processo A se mostrou mais eficiente em termos energéticos, requerendo cerca de 20% da carga térmica requerida no processo B, além de ser mais compacto na quantidade de operações unitárias necessárias. / A conceptual process design study was carried out, aimed at the design of a triacetin production unit from glycerol, as a way to increase the feasibility of biodiesel production. Glycerol esterification with acetic acid involves three consecutive reversible acetylation reactions. In each step, water is produced, resulting in limited conversion and low selectivity. One way to increase the selectivity of triacetin is to continuously remove water from the reaction medium in order to shift the equilibrium. Two processes were considered, based on different kinetics. Process A is based on the reaction system described by Mufrodi et al. (2012), which employs sulfuric acid as catalyst, and process B is based on the system described by Galan et al. (2009), which consists of the esterification of glycerol using acetic acid in excess as catalyst. Both processes were simulated using a reactive distillation column and hexane as a water entrainment booster, and different configurations were studied by using the Aspen Plus® simulator. The conceptual process specifications of an optimized industrial plant capable of processing glycerol produced in a typical Brazilian biodiesel producer facility were estimated, for both processes, in order to minimize the specific energy consumption and produce triacetin with a molar purity of 99.9%, with complete conversion of glycerol. Process A showed to be more energy efficient, requiring about 20% of the heat duty required in process B, and being more compact in the necessary quantity of unit operations.

The esterification of lactic acid with ethanol over Lewatit S 100, strong cation ion exchange resin catalyst, was studied in counter current vapor-liquid contactor type differential reactor by feeding ethanol and lactic acid solution as vapor and liquid phases, respectively. The ethanol vapor phase was diluted by dry air and the water removal was achieved by the mass transfer of water from liquid to vapor phase. Effect of ethanol to lactic acid feed molar ratio and vapor flow rate on fractional conversion and water removal efficiency were tested at 40-70&deg / C of column temperature range. It was observed that Lewatit S 100 was adequate catalyst for esterification of lactic acid with ethanol. Increase in ethanol to lactic acid feed molar ratio enhanced both lactic acid conversion and water removal by upper product stream. However, lactic acid conversion was suppressed by the increase of inlet vapor flow rate because of the decrease in ethanol concentration in gas phase which affected both esterification reaction rate and mass transfer rate. The reaction temperature is the other important parameter that affects the mass transfer of ethanol from vapor to liquid phase. Although reaction rate and equilibrium conversion values were promoted by temperature, the lower solubility of ethanol in liquid phase limited the fractional conversion while promoted the water mass transfer from liquid to vapor phase. The optimized vapor phase velocity and temperature can yield higher conversions than the equilibrium conversion at the same temperature and initial composition. Therefore, low pressure organic acids such as lactic acid can be successfully esterified by using counter current V-L contactor type reactors and by using integrated reaction and separation units.

Foi realizado um estudo de desenvolvimento de projeto conceitual de uma unidade produtora de triacetina a partir de glicerol, como forma de aumentar a viabilidade de produção de biodiesel. A esterificação de glicerol com ácido acético envolve três reações de acetilação reversíveis consecutivas. Em cada etapa, água é produzida, resultando em conversão limitada e baixa seletividade. Uma forma de aumentar a seletividade da triacetina consiste em remover continuamente a água do meio reacional, de modo a alterar o equilíbrio. Foram considerados dois processos baseados em cinéticas diferentes. O processo A proposto baseia-se no sistema reacional descrito por Mufrodi et al. (2012), que emprega ácido sulfúrico como catalisador e o processo B baseia-se no sistema descrito por Galan et al. (2009), que consiste na esterificação de glicerol utilizando ácido acético em excesso como catalisador. Os dois processos foram simulados usando uma coluna de destilação reativa com hexano como potencializador do arraste de água, e diferentes configurações foram estudadas usando o simulador Aspen Plus®. As especificações do processo conceitual de uma unidade industrial otimizada, capaz de processar o glicerol produzido em uma unidade típica produtora de biodiesel, foram estimadas para os dois processos em termos de mínimo consumo específico de energia e produção de triacetina de pureza molar de 99,9%, com conversão completa de glicerol. O processo A se mostrou mais eficiente em termos energéticos, requerendo cerca de 20% da carga térmica requerida no processo B, além de ser mais compacto na quantidade de operações unitárias necessárias. / A conceptual process design study was carried out, aimed at the design of a triacetin production unit from glycerol, as a way to increase the feasibility of biodiesel production. Glycerol esterification with acetic acid involves three consecutive reversible acetylation reactions. In each step, water is produced, resulting in limited conversion and low selectivity. One way to increase the selectivity of triacetin is to continuously remove water from the reaction medium in order to shift the equilibrium. Two processes were considered, based on different kinetics. Process A is based on the reaction system described by Mufrodi et al. (2012), which employs sulfuric acid as catalyst, and process B is based on the system described by Galan et al. (2009), which consists of the esterification of glycerol using acetic acid in excess as catalyst. Both processes were simulated using a reactive distillation column and hexane as a water entrainment booster, and different configurations were studied by using the Aspen Plus® simulator. The conceptual process specifications of an optimized industrial plant capable of processing glycerol produced in a typical Brazilian biodiesel producer facility were estimated, for both processes, in order to minimize the specific energy consumption and produce triacetin with a molar purity of 99.9%, with complete conversion of glycerol. Process A showed to be more energy efficient, requiring about 20% of the heat duty required in process B, and being more compact in the necessary quantity of unit operations.

Orientador: Maria Regina Wolf Maciel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-16T23:15:28Z (GMT). No. of bitstreams: 1 Santander_CarlosMarioGarcia_M.pdf: 4264150 bytes, checksum: fefe44cf2580cae6314ee081507c6626 (MD5) Previous issue date: 2010 / Resumo: Neste trabalho, foi estudado o processo de destilação reativa para produção de biodiesel usando óleo de mamona e óleo de soja como matérias primas. Simulações do processo utilizando o simulador comercial Aspen plus® em conjunto com técnicas de planejamentos fatoriais permitiram encontrar as condições de operação que irão produzir a maior quantidade de biodiesel. Inicialmente, foi realizada a caracterização dos óleos vegetais e os biodieseis por meio de compostos representativos das misturas que os compõem no simulador. Para isto, foram realizadas medições experimentais de algumas propriedades dos compostos em estudo. As simulações foram efetuadas utilizando o modelo termodinâmico NRTL com os parâmetros de interação faltantes na base de dados do simulador estimados pelo método UNIFAC. O modelo cinético empregado no caso da mamona foi o publicado por de Lima da Silva (2008). Dado que na literatura não se encontram reportados parâmetros cinéticos da transesterificação do óleo de soja com etanol, neste trabalho, esses parâmetros foram determinados e utilizados nas simulações. Para o sistema de produção de biodiesel de mamona, inicialmente foi desenvolvido um planejamento fatorial 24 com o objetivo de analisar o efeito das variáveis: vazão de alimentação de óleo (vo), relação molar álcool: óleo (rm), razão de refluxo (rf) e relação molar entre o destilado/alimentação com base no etanol (d:f) sobre o rendimento do processo e ao mesmo tempo obter um modelo que representasse de forma adequada o comportamento do sistema. Em seguida, foi utilizada a metodologia da máxima inclinação para determinar de forma rápida e simples a região que irá maximizar a produção de biodiesel. Finalmente, com base nos resultados obtidos no item anterior, foi desenvolvido um novo planejamento 24 para encontrar a melhor combinação das variáveis que permita se obter a maior produção de biodiesel. Estudos de sensibilidade foram realizados para suportar os resultados obtidos dos planejamentos. Para o estudo do sistema de produção envolvendo óleo de soja, seguiu-se a mesma metodologia exposta para o óleo de mamona, com a diferença de que os planejamentos foram 23. Os resultados obtidos com os dois óleos, mostram que é possível obter altos rendimentos no processo utilizando uma baixa relação molar etanol:óleo e uma planta mais compacta. Adicionalmente, foram introduzidos nas simulações valores de eficiência por estágio e por componente calculados usando a equação de Barros e Wolf, verificando que a eficiência não tem efeito representativo no desempenho do processo. Foi realizada também a simulação de uma coluna de destilação com recheio para produção de biodiesel. As condições de operação da simulação foram tomadas de um estudo experimental realizado pelo grupo de pesquisa em biodiesel do laboratório LDPS (Laboratório de Desenvolvimento de Processos de Separação), o qual se encontra reportado nesta dissertação / Abstract: In this work, the reactive distillation process for biodiesel production using castor oil and soybean oil as feedstocks is presented. Process simulations using the commercial simulator Aspen plus® in conjunction with factorial design techniques were used for finding the process operating conditions that will produce the largest amount of biodiesel. For the simulations, firstly, the characterization of vegetable oils and biodiesels by means of representative compounds was performed into the simulator. It was necessary, for a successfull characterization, to carry out experimental measurements of some properties of these compounds. The simulations were performed using the NRTL thermodynamic model. The interaction parameters missing in the simulator data base were estimated by UNIFAC method. The kinetic model employed in castor oil study was published by de Lima da Silva. Because kinetic data for soybean oil transesterification with ethanol are not reported in the open literature, these parameters were determined and used in the simulations. In the study of the castor oil biodiesel production system, initially a 24 factorial design was done in order to analyze the effect of the variables: feed flow rate of oil (vo), molar ratio alcohol: oil (rm), reflux ratio (rf) and molar ratio between the distillate / feed based on ethanol (d: f) in the process yield and simultaneously to obtain a model that adequately represents the behavior of the system. Following this, it was used the method of the path of steepest ascent to determine quickly and simply the region that will maximize the production of biodiesel. Finally, based on results obtained in the previous section, it was developed a new factorial design 24 to find the best combination of variables, which would provide the largest biodiesel production. Sensitivity studies were performed to support the factorial design results. In the study of the system involving soybean oil, was followed the same methodology described for the castor oil, with the difference that the factorial designs were all 23. The results obtained with the twou oils show that it is possible to obtain high yields in the process using a low molar ratio ethanol: oil and a more compact plant. Additionally, it was introduced in the simulations, stage efficiency values and component efficiency values calculated using the Barros & Wolf equation. It was concluded that efficiency has no effect on the performance of the reactive distillation process for biodiesel production. Finally, it was performed a simulation of a reactive packed distillation column for biodiesel production. The operating conditions of the simulation were taken from na experimental study conducted by the research group in biodiesel lab LDPS, which is reported in this dissertation / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientador: Rubens Maciel Filho, Maria Regina Wolf Maciel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T09:35:16Z (GMT). No. of bitstreams: 1 Custodio_AlineFerrao_D.pdf: 2173448 bytes, checksum: 27b046c8dc2de1781ef672eb1c4ab063 (MD5) Previous issue date: 2007 / Resumo: Este trabalho de tese propôs um processo para a produção de acetato de etila através da reação de esterificação do ácido acético com o etanol, utilizando conceitos de intensificação de processos e de Engenharia Verde (Zero Avoidable Pollution com renweable feedstock). A contribuição principal desta pesquisa é a proposta de uma planta conceitual com alta pureza de todas as correntes do processo, o que diminui desperdícios, de modo que o produto indesejado ou os reagentes não convertidos não estejam presentes nas correntes de saída do sistema. No processo proposto, todos os reagentes são de origem renovável. O acetato de etila é um solvente orgânico importante utilizado na produção de vernizes, de tintas, de resinas sintéticas e de agentes adesivos, sendo produzido normalmente, através da reação reversível do ácido acético com o etanol, com ácido sulfúrico com catalisador. O processo deste sistema de obtenção é bastante complexo porque o produto (acetato de etila) não é o componente mais volátil nem o menos volátil no sistema, de modo que a etapa de separação não é fácil de definir. O projeto conceitual proposto inclui um reator de tanque contínuo (CSTR) acoplado a um retificador, um decantador e duas colunas de purificação, para a água e o acetato de etila. O software comercial ASPEN PLUS® foi utilizado para a realização dos estudos do processo proposto através de simulação computacional em estado estacionário, e o simulador ASPEN DYNAMICS® foi utilizado para a simulação dinâmica / Abstract: This work proposes a process for ethyl acetate production via esterification of acetic acid with ethanol using concepts of process intensification and zero avoidable pollution. The main contribution of this work is the high-purity of all process streams, including the wastes ones, so that undesired product or unconverted reactants are not present in any throughput streams. Ethyl acetate is an important organic solvent widely used in the production of varnishes, ink, synthetic resins, and adhesive agents and it is normally produced via reversible reaction of acetic acid with ethanol, with sulfuric acid as catalyst. The process design of such system is complex because the ethyl acetate product is neither the lightest nor the heaviest component in the system, so that the separation stage is not an easy task. The proposed process design includes a continuous-stirred tank reactor (CSTR) coupled with a rectifier, a decanter and two purification columns for water and ethyl acetate. The commercial ASPEN PLUS® software was used to steady state simulation and ASPEN DYNAMICS® was used to dynamic simulation / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

No description available.

yes / Batch reactive distillation is aimed at achieving a high purity product, therefore, there is a great deal to find an optimal operating condition and effective control strategy to obtain maximum of the high purity product. An off-line dynamic optimization is first performed with an objective function to provide optimal product composition for the batch reactive distillation: maximum productivity. An inferential state estimator (an extended Kalman filter, EKF) based on simplified mathematical models and on-line temperature measurements, is incorporated to estimate the compositions in the reflux drum and the reboiler. Model Predictive Control (MPC) has been implemented to provide tracking of the desired product compositions subject to simplified model equations. Simulation results demonstrate that the inferential state estimation can provide good estimates of compositions. Therefore, the control performance of the MPC with the inferential state is better than that of PID. In addition, in the presence of unknown/uncertain parameters (forward reaction rate constant), the estimator is still able to provide accurate concentrations. As a result, the MPC with the inferential state is still robust and applicable in real plants.

Organic esters are an important class of industrial and commercial chemicals that can be found in solvents, plasticizer, food flavours, detergents, agrochemicals, and pharmaceuticals. The most common way to synthesis organic esters is with esterification or transesterification. Where esterification was the chosen method in this thesis.  This thesis provides a techno-economic assessment on the production of propyl acetate and glycerol trivalerate through different continuous routes that is than compared with batch production under the same conditions. Simulations was done on trivalerate due to limited literature and data on pentaerythritol tetravalerate. Different continuous technologies that have been assessed in this thesis was plug flow reactor (PFR), Reactive Distillation (RD), and Reactive – Extractive Distillation (RED). The production of mono- and polyol esters with different unit operators was simulated in Aspen Plus V.14. Techno-Economic analysis was conducted with APEA (Aspen Process Economic Analyzer), where cost of raw materials, products, and utilities was inserted to evaluate annual operating cost and product sale. Reaction kinetic for esterification of trivalerate was estimated by obtained values from simulations of a Gibbs reactor in Aspen Plus at four different temperatures. Kinetics was estimated by applying the relation between the chemical equilibrium constant and the Arrhenius equation. Where rate constant and activation energy for forward and revers reaction was obtained by varying min and max values for lsqcurvefit in MATLAB and then validate results with published kinetics.  Results from production of propyl acetate with batch, PFR and RED provides an annual profit of approximately 1 M$ at a capacity of 41.65 kton/year. The three different process provides also approximately an equal capital cost, operating cost, equipment cost, and installed cost according to APEA. RED provided the lowest propyl acetate yield at 93%, batch and PFR provided a propyl acetate yield of 94%.  Results from production of trivalerate with batch, PFR, and RD provides an annual profit of 5.4, 5.78, and 9.2 M$ at a capacity of approximately 5 kton/year. Where RD process provides the lowest capital cost, operating cost, equipment cost, and installed cost compared to batch and PFR processes according to APEA. Obtained results from production of trivalerate can be used to evaluate the economic and technical feasibility of a continuous production plant for pentaerythritol tetravalerate (PETV). Where initial simulations show a good economic and technical viability of a continuous ester production plant.