Computational simulation of deodorization and deacidification of vegetable oils. / Simulação computacional de processos de desodorização e desacidificação de oleos vegetais.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

This work was developed in order to study through simulation, the processes of deacidification by steam refining and deodorization, present in the vegetable oil industry. The modeling was developed for batch and continuous processes in steady-state and dynamic regime. To describe mass and energy balances, and equilibrium relationships, it was necessary to use empirical equations and/or predictive models to calculate physical properties of all compounds of the mixture, as vapor pressure, heat capacities, vaporization enthalpies, activity coefficients, fugacity coefficients and critical properties. Because of the great variety of experimental data for the vapor pressure of fatty compounds available in the literature, the first step of this work was to adjust a predictive equation for this property using the concept of group contribution. In combination with the UNIFAC model (UNIquac Functional group Activity Coefficients), several vapor-liquid equilibrium data for binary (fatty acids, fatty esters and triacylglycerols) and multicomponent (oil/solvent miscellas) mixtures were predicted with success using a computational program developed to calculate the boiling points. The second step was to study the batch steam refining, modeling the process as a differential distillation. The computational program was used in the simulation of an experimental work with coconut oil. In the next step, the elaboration of the complete simulation program for a multicomponent stripping column was carried out through the use of subroutines for calculation of activity and fugacity coefficients, vapor pressures, heat capacities and vaporization enthalpies for each of the oil compounds and of vapor, besides the convergence algorithm using the Newton-Raphson method. Some vegetable oils were selected and their processing conditions were simulated to evaluate their influence on the composition of the product streams (refined oil and distillate), in terms of final oil acidity, neutral oil loss and losses of nutraceutical compounds. Murphree efficiency and entrainment were also included in the program. Degradative chemical reactions, occasioned by the high temperatures of these processes, as polyunsaturated fatty acid isomerization, were also evaluated in the batch process. A complementary task was modeling the vaporization efficiency of the deodorization process of vegetable oils, associated with the transfer of the free acidity present in the liquid phase to an ascending bubble of steam, that expands due to a variation in the hydrostatic pressure throughout the liquid height. To end this work, the steam refining was simulated dynamically. All computational programs were developed using MatLab.

ASSUNTO(S)

desodorização simulação vegetable oils oleos vegetais deodorization simulation equilibrio liquido-vapor modelagem vapor-liquid equilibria modeling

ACESSO AO ARTIGO

Documentos Relacionados