Produção de biodiesel por esterificação em coluna de destilação reativa : modelagem matemática

• Autor(a) principal: Machado, Guilherme Duenhas
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3801
• topic: Biodiesel; Produção; Esterificação; Destilação reativa; Coluna de destilação reativa; Modelagem matemática; Simulação computacional; Brasil.; Biodiesel; Reactive distillation column; Simulation; Esterification; Brazil.; Engenharias; Engenharia Química

The Development of renewable energy sources has become a necessity of extreme importance to the planet due the rise of consequences of global warming in recent years and the inevitable shortage of fossil fuels. For this reason, the production of biodiesel (fatty acid esters) has achieved prominence in the last decade. The conventional method for biodiesel production is the transesterification of vegetal oils using homogeneous catalysis in batch processes. In this case, the production is performed in two stages: the chemical reaction and the separation of products. Several studies have been done in order to provide alternative methods to enable the production of fatty acid esters. Recently, the production of biodiesel by esterification of fatty acids has gained some prominence. This process of production presents several advantages, but it is still require two distinct stages of reaction and separation. In this context, the reactive distillation method rises as a viable alternative for the production of biodiesel by esterification. In such operation, the chemical reaction and separation of products occur continuously in the same equipment. Therefore, the objective of this work is to simulate the production of fatty acid esters (biodiesel) in steady state reactive distillation columns. The simulation model used here doesn't suppose chemical equilibrium in the stages, but the occurrence of steady state. In this way, the reaction rates are considered explicitly in the model of each stage. It is considered ideal behavior in the vapor and non-ideality in the liquid phase is represented by the models of Gibbs free energy of excess UNIQUAC and UNIFAC Dortmund. Initially, the mathematical formulation used is validated by comparing the results calculated in this work with the available cases in the literature. Next, new cases of biodiesel production by esterification in reactive distillation columns are simulated. In these cases, sensitivity analysis of design and operating variables such as reflux ratio, number of stages, heat input in the reboiler, mass of catalyst and reaction order are performed. The sensitivity analyses are carried out in order to determine the influence of several parameters in the optimization of the column operation. The heat input in the reboiler can be reduced by the increase of energy charge in the feed of reagents. This modification reduces the temperature of the bottom of the column and avoids the degradation of products. Conversions close to 99% were found. The simulation results obtained here can be useful for the proper design of processes that use reactive distillation columns for the production of biodiesel.