CACHACA DISTILLATION INVESTIGATED ON THE BASIS OF MODEL SYSTEMS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This work reports experimental tests using commercial spirits that were diluted and had their initial composition modified in order to better measure the distillation behavior of selected minor compounds of importance for the quality of alcoholic beverages. Such compounds were added to the commercial cachaca and the corresponding model wine, obtained after the spirits' dilution, was distilled. In this way a more precise distillation profile could be determined for those minor compounds. The alembic heating was performed by electrical resistance and the corresponding heat transfer coefficient was determined by analyzing the thermal behavior of the still during the distillations. A simulation algorithm was developed, including the mass and enthalpy balances as well as the heat transfer flux to the boiling wine. Good agreement between experimental and simulated results was obtained for the distillate rate, alcoholic graduation, temperature and most minor component profiles.292429440Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [06/04471-4, 08/56258-8]CNPq [303650/2007-1

Predicting vapor-liquid equilibria of fatty systems

In the present work, a group contribution method is proposed for the estimation of the vapor pressure of fatty compounds. For the major components involved in the vegetable oil industry, such as fatty acids, esters and alcohols, triacylglycerols (TAGs) and partial acylglycerols, the optimized parameters are reported. The method is shown to be accurate when it is used together with the UNIFAC model for estimating vapor-liquid equilibria (VLE) of binary and multicomponent fatty mixtures comprised in industrial processes such as stripping of hexane, deodorization and physical refining. The results achieved show that the group contribution approach is a valuable tool for the design of distillation and stripping units since it permits to take into account all the complexity of the mixtures involved. This is particularly important for the evaluation of the loss of distillative neutral oil that occurs during the processing of edible oils. The combination of the vapor pressure model suggested in the present work with the UNIFAC equation gives results similar to those already reported in the literature for fatty acid mixtures and oil-hexane mixtures. However, it is a better tool for predicting vapor-liquid equilibria of a large range of fatty systems, also involving unsaturated compounds, fatty esters and acylglycerols, not contemplated by other methodologies. The approach suggested in this work generates more realistic results concerning vapor-liquid equilibria of systems encountered in the edible oil industry. (C) 2003 Elsevier B.V. All rights reserved.215222723

Computer simulation applied to studying continuous spirit distillation and product quality control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This work aims to study continuous spirit distillation by computational simulation, presenting some strategies of process control to regulate the volatile content. The commercial simulator Aspen (Plus and dynamics) was selected. A standard solution containing ethanol, water and 10 minor components represented the wine to be distilled. A careful investigation of the vapor-liquid equilibrium was performed for the simulation of two different industrial plants. The simulation procedure was validated against experimental results collected from an industrial plant for bioethanol distillation. The simulations were conducted with and without the presence of a degassing system, in order to evaluate the efficiency of this system in the control of the volatile content. To improve the efficiency of the degassing system, a control loop based on a feedback controller was developed. The results showed that reflux ratio and product flow rate have an important influence on the spirit composition. High reflux ratios and spirit flow rates allow for better control of spirit contamination. As an alternative to control the volatile contents, the degassing system was highly efficient in the case of low contamination. For a wine with high volatile contamination, the pasteurized spirit distillation unit was the best alternative. (C) 2011 Elsevier Ltd. All rights reserved.221015921603Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2008/56258-8]CNPq [304495/2010-7

Debt, financial fragility, and economic growth: a Post Keynesian macromodel

A Post Keynesian macromodel of capacity utilization and economic growth is developed in which the supply of credit-money by the banking system is endogenous, and firms' financial fragility is explicitly modeled. Both the influence of interest rate and indebtedness on capacity utilization and the rates of profit and economic growth, on the one hand, and the effect of the parameters of the saving and investment functions on firms' financial fragility, on the other hand, are carefully analyzed.2919311

Simulation of continuous physical refiners for edible oil deacidification

Physical refining, also known as deacidification by steam distillation, is a process in which free fatty acids and other volatile compounds are distilled off from the oil, using an effective stripping agent (usually steam) and suitable processing conditions. In general, vegetable oils are formed by triacylglycerols, free fatty acids, partial acylglycerols and some minor compounds, constituting a complex mixture. This work presents the implementation of a simulation program applied to the physical refining of edible oils, following a multicomponent-stripping tray-column design. Two singular vegetable oils, from palm and coconut, were selected. Their entire compositions were considered within the simulations, including acylglycerols and free fatty acids. To describe the required physical properties, group contribution methods and empirical equations were selected. The results were analyzed and compared with the literature in terms of neutral oil loss and final oil acidity, as a function of the processing conditions. Murphree efficiencies and entrainment were considered for each plate. (c) 2005 Elsevier Ltd. All rights reserved.76326127

Deacidification of corn oil by solvent extraction in a perforated rotating disc column

The deacidification of corn oil by continuous liquid-liquid extraction was investigated in a rotating disc column. The solvent was ethanol containing approximately 6% water. The influence of rotor speed, oil phase flow, and column geometry upon the dispersed phase holdup and the mass transfer efficiency was studied. The dispersed phase holdup increased with the increase of rotor speed and oil phase flow. Pratt's equation was used for calculating the characteristic velocity. An inverse relation was observed between the characteristic velocity and rotor speed, which is different from data previously reported in the literature. The estimated volumetric mass transfer coefficients increased as rotor speed and oil phase flow increased. The experimental results proved that it is feasible to obtain a refined oil with an oleic acid content less than 0.3 wt% by continuous solvent extraction. They also indicated that the corresponding loss of neutral oil was less than 5 wt%. Such value for the loss of neutral oil is significantly lower than the results reported in the literature for alkali or physical refining of corn oil.77555355

Oleic acid removal from ethanolic solutions by ion exchange

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Oleic acid uptake from ethanolic solutions was studied at (298.15 +/- 0.1) K using a strong anion exchange resin (Amberlyst A26OH). Kinetic data measured at a high stirring rate and different oleic acid concentrations were correlated assuming that the mass transfer resistance is concentrated in the solid phase. In this way it was possible to determine the effective diffusivities of the solute inside the porous structure of the resin. The oleic acid concentration (8-16% by mass) did not influence the calculated values. They were employed as initial estimates for modeling breakthrough data reported on the literature, using the package Chromatography from Aspen Plus software. The selected model takes into account the mass transfer around the resin beads, the axial dispersion in the liquid phase and the diffusion inside the resin phase. The parameter selected for the fitting procedure was the effective diffusivity, so that the values obtained from the modeling of the breakthrough curves and those from the kinetic study could be compared. Both set of values were coherent, varying within the range from (4.5 to 10.2) x 10(-12) m(2) s(-1). This study indicates that the removal of oleic acid from ethanolic solutions using ion exchange is a viable process. (C) 2012 Elsevier B.V. All rights reserved.184125131Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [140487/2005, 304495/2010-7 + 480992/2009-6]FAPESP [02/11794-3, 08/56258-8 + 09/54137-1

Simulation of batch physical refining and deodorization processes

This work presents an application of a differential distillation model for the simulation of batch physical refining and/or deodorization processes in the vegetable oil industry. The vapor-liquid equilibria of these fat systems are described by group contribution equations for vapor pressures and activity coefficients published elsewhere (Ceriani, R., and A.J.A. Meirelles, Predicting Vapor-Liquid Equilibria of Fatty Systems, Fluid Phase Equilib. 215:227-236, 2004; Fredenslund, A., J. Gmehling, and P. Rasmussen, Vapor-Liquid Equilibria Using UNIFAC, Elsevier Scientific, Amsterdam, 1977). The full complexity of the oil, expressed as its total composition of TAG, DAG, MAG, and FFA, is considered within the simulation. This approach permitted us to quantify and qualify distillative neutral oil losses during physical refining. Three different models of differential distillation were tested to develop a good representation of the batch process to be applied to the physical refining and/or deodorization of complex mixtures such as vegetable oils. To evaluate the recommended approach, a case study was performed, namely, a batch deodorizer was simulated for coconut oil refining, and the results were compared with those reported in the literature.81330531

Water activity, pH and density of aqueous amino acids solutions

The water activity, pH and density of some aqueous amino acid solutions were determined at 25 degreesC in three different types of solvents. Previous published experimental data on water activity and solubility of amino acids in aqueous solutions were used together with data from this work to test the applicability of a group contribution model. The activity coefficients were estimated by the UNIFAC-Larsen model combined with the Debye-Huckel equation, taking also into account the partial dissociation phenomena of species in solution. Interaction energies between the charged species Na+ and Cl- and the specific groups of amino acids (COOH and NH2) were adjusted using experimental solubility data.17470371