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Abstract(s)
Desde há muito tempo que a utilização dos vários processos de separação se tem tornado significativa nos mais diversos tipos de indústria. Os processos de separação são selecionados adequadamente para o objetivo de separação que se pretende, sendo por isso processos/operações específicas. A destilação é o processo de separação mais utilizado e tem como princípio separar componentes de misturas por diferença de volatilidade. A empresa Bioportdiesel, S.A., na qual se desenvolveu este trabalho, possui uma torre de retificação para recuperar o metanol existente nas correntes do processo de produção do biodiesel. A torre opera em estado não estacionário, em lotes consecutivos, com correntes de alimentação e produto de topo contínuas. A inexistência de um produto de cauda atribui a este equipamento uma classificação do modo de operação entre a operação em batch e em contínuo. O estudo realizado nesta dissertação consistiu em duas etapas: a primeira de estudo de possíveis alterações visando a recuperação do metanol residual no final do processamento de cada lote e a segunda incidindo na simulação do processo de destilação referido usando o simulador (ASPEN PLUS, v.8.6 – módulo BatchSep), com o objetivo de modelar o equipamento de destilação e conseguir prever e otimizar o comportamento do mesmo. De forma a melhorar o processo de recuperação do metanol com o objetivo de minimizar custos, quer no consumo de energia térmica quer no tratamento dos resíduos resultantes do funcionamento da torre, procedeu-se a um estudo de recuperação do metanol através de uma etapa adicional de evaporação. Procedeu-se ao levantamento, em diferentes lotes, das condições de operação da coluna, como temperaturas e pressão de funcionamento, bem como caracterização da composição das correntes associadas. Para recuperar o metanol residual resultante dos lotes da torre procedeu-se à realização de dois testes: recuperação por evaporação do metanol residual, após o esgotamento normal de um lote e após esgotamento estrategicamente antecipado. No primeiro teste obteve-se uma redução de custos de 30% e no segundo uma redução de 34%. Após este estudo procedeu-se à simulação da destilação do metanol. As simulações foram realizadas com algumas limitações por desconhecimento da geometria interna da coluna, tendo-se encontrado o ponto de partida para a simulação e validação do modelo representativo da torre de retificação. Nas simulações efetuadas conseguiram-se obter resultados próximos dos obtidos na coluna real com exceção das perdas de carga na coluna que foram cerca de 3,6 vezes superiores às reais.
The use of the various separation processes has been significant in many different types of industry. The separation processes are suitably selected for the purpose of the separation that is intended, being therefore specific processes/operations. Several are the separation processes currently used by industries. Distillation is the most widely used separation process and is intended to separate components of mixtures by the difference of their volatilities. This operation can be used to recover components from mixtures/process streams, and/or to correct their flows. The company Bioportdiesel, S.A., in which this work was developed, has a rectification tower to recover methanol in the streams of the biodiesel production process. The tower operates in non-stationary state, in consecutive batches, with continuous feeding streams and product from the top. The absence of a bottom product gives this equipment a classification of the mode of operation between batch operation and continuous operation. The study carried out in this dissertation consisted of two stages: the first is the study of possible alterations aiming the recovery of the residual methanol at the end of each batch and the second focusing on the simulation of the referred distillation process using the simulator (ASPEN PLUS, v. 8.6 - BatchSep module), with the objective of modeling the distillation equipment and being able to predict and optimize its behavior. In order to improve the methanol recovery process to minimize costs, both in thermal energy consumption and in the treatment of waste resulting from tower operation, a methanol recovery study was carried out through an additional stage of evaporation. The operating conditions of the column, such as operating temperatures and pressure, as well as characterization of the composition of the associated streams, were surveyed in different batches. In order to recover residual methanol from the tower bottoms, two tests were performed: recovery by evaporation of residual methanol at the end of a normal batch and at a strategically shorter batch. It was achieved in the first test a cost reduction of 30% and 34% in the second one. After this study the simulation of the methanol distillation was performed. The simulations were carried out with some limitations due to lack of information of the internal geometry of the column, but a starting point for the simulation and validation of the representative model of the rectification tower was found. In the simulations that were carried out the results were close to those obtained in the actual column with the exception of pressure drop through the column that was about 3.6 times higher than the real one.
The use of the various separation processes has been significant in many different types of industry. The separation processes are suitably selected for the purpose of the separation that is intended, being therefore specific processes/operations. Several are the separation processes currently used by industries. Distillation is the most widely used separation process and is intended to separate components of mixtures by the difference of their volatilities. This operation can be used to recover components from mixtures/process streams, and/or to correct their flows. The company Bioportdiesel, S.A., in which this work was developed, has a rectification tower to recover methanol in the streams of the biodiesel production process. The tower operates in non-stationary state, in consecutive batches, with continuous feeding streams and product from the top. The absence of a bottom product gives this equipment a classification of the mode of operation between batch operation and continuous operation. The study carried out in this dissertation consisted of two stages: the first is the study of possible alterations aiming the recovery of the residual methanol at the end of each batch and the second focusing on the simulation of the referred distillation process using the simulator (ASPEN PLUS, v. 8.6 - BatchSep module), with the objective of modeling the distillation equipment and being able to predict and optimize its behavior. In order to improve the methanol recovery process to minimize costs, both in thermal energy consumption and in the treatment of waste resulting from tower operation, a methanol recovery study was carried out through an additional stage of evaporation. The operating conditions of the column, such as operating temperatures and pressure, as well as characterization of the composition of the associated streams, were surveyed in different batches. In order to recover residual methanol from the tower bottoms, two tests were performed: recovery by evaporation of residual methanol at the end of a normal batch and at a strategically shorter batch. It was achieved in the first test a cost reduction of 30% and 34% in the second one. After this study the simulation of the methanol distillation was performed. The simulations were carried out with some limitations due to lack of information of the internal geometry of the column, but a starting point for the simulation and validation of the representative model of the rectification tower was found. In the simulations that were carried out the results were close to those obtained in the actual column with the exception of pressure drop through the column that was about 3.6 times higher than the real one.
Description
Keywords
Simulação Destilação Processos de separação Simulation Distillation Separation processes