Modeling Of Phase And Chemical Equilibria For Systems Involved In Biodiesel Production

In recent years, the interest in the use of renewable energy has encouraged the growth of studies into renewable sources, such as the production of biofuels. This work investigates the vapor-liquid equilibrium (VLE), vapor-liquid-liquid equilibrium (VLLE) and liquid-liquid equilibrium (LLE) of binary, ternary, quaternary and pseudo-quaternary systems using an optimization approach for components found in biodiesel production, which consists in vegetable oils, fatty acids, esters and alcohols. A methodology has been developed based on the Gibbs energy minimization and the discretization of the molar fraction domain, which incorporates a thermodynamic model to describe the phase equilibria. This work used the Soave-Redlich-Kwong equation of state (SRK-EOS) for phase equilibria calculation, where the compressibility factor was used to determine the phase present in the system (liquid, vapor or supercritical fluid). The chemical and phase equilibrium problem is solved using linear programming and satisfies the mass balance constraints. It was found that the proposed methodology adequately represents the selected experimental data, with an average absolute deviation of 1.31 % obtained.431855186

Density Measurements of CO2-Expanded Liquids

Novel experimental data of density for mixtures containing CO2 + ethanol, CO2 + ethyl lactate, CO2 + glycerol + ethanol, and CO2 + glycerol + ethyl lactate at low/moderate temperatures (308 and 323 K), pressures between 5 and 30 MPa, and high amounts of the organic solvent (molar fraction x = 0.5-0.9) are presented. The chosen organic solvents (ethanol, ethyl lactate, and glycerol) are green and applicable in food industry and present different polarizabilities. The density of CO2 + ethanol increased with the increment in the molar fraction of CO2, and the opposite was observed for the mixtures of CO2 + ethyl lactate. By adding a small amount of glycerol to the mixture of CO2 + ethanol and CO2 + ethyl lactate, it was possible to increase the density even a little further. The experimental data of density were well-correlated using the Peng-Robinson equation of state (PR-EOS) combined with Péneloux volume translation

Density Measurements of CO₂‑Expanded Liquids

Novel experimental data of density for mixtures containing CO₂ + ethanol, CO₂ + ethyl lactate, CO₂ + glycerol + ethanol, and CO₂ + glycerol + ethyl lactate at low/moderate temperatures (308 and 323 K), pressures between 5 and 30 MPa, and high amounts of the organic solvent (molar fraction <i>x</i> = 0.5–0.9) are presented. The chosen organic solvents (ethanol, ethyl lactate, and glycerol) are green and applicable in food industry and present different polarizabilities. The density of CO₂ + ethanol increased with the increment in the molar fraction of CO₂, and the opposite was observed for the mixtures of CO₂ + ethyl lactate. By adding a small amount of glycerol to the mixture of CO₂ + ethanol and CO₂ + ethyl lactate, it was possible to increase the density even a little further. The experimental data of density were well-correlated using the Peng–Robinson equation of state (PR-EOS) combined with Péneloux volume translation

Experimental measurements and modeling of curcumin solubility in CO2-expanded ethanol

Carbon dioxide expanded liquids (CXLs) is a relatively recent type of solvent used in separation processes such as extraction. It combines the benefits of high solubility in the organic liquid with enhanced mass transfer mediated by the compressed CO2. In this work, we investigate the solubility of curcumin in CO2-expanded ethanol and for this purpose an equipment setup was built and used for experimental measurements at the temperatures of 308 and 323K and the pressure range of 10-30MPa. The amount of CO2 added to ethanol was varied between 10 and 50mol%. Results show that the highest solubility of curcumin was obtained at the highest temperature and the lowest amounts of CO2 (10mol%) in the mixture. Moreover, the new-built equipment setup allows the determination of the solubility for compounds with high molar light absorptivity such as curcumin. The experimental data was correlated using PR-EOS and the modified Chrastil model

Solubility and Thermal Degradation of Quercetin in CO2-Expanded Liquids

The solubility of quercetin and its thermal degradation was studied in CO2-expanded ethanol and ethyl lactate. An equipment setup was constructed that enabled the separation of the products of degradation while quantifying the solubility of quercetin. Three different conditions of temperature were analyzed (308, 323, and 343 K) at 10 MPa. Higher solubility and thermal degradation of quercetin were observed for CO2-expanded ethyl lactate in comparison with CO2-expanded ethanol. At the same time, as the amount of CO2 was increased in the CO2-expanded liquids mixtures, the thermal degradation of quercetin decreased for almost all the conditions of temperature considered in this work. The importance of considering thermal degradation while performing solubility measurements of compounds that are thermally unstable such as quercetin was highlighted

Multicomponent inverse modeling of supercritical fluid extraction of carotenoids, chlorophyll A, ergosterol and lipids from microalgae

The fundamentals of analyte extractable fraction, solubility, partitioning and mass transfer resistance in supercritical fluid extraction were studied using inverse modeling. These phenomena are essential for understanding, predicting and optimizing the supercritical fluid extraction process. Carotenoids, chlorophyll A, ergosterol and total lipids were extracted from the microalgae Chlorella sp. The analytes were measured continuously in-line and on-line using UV/Vis absorption spectroscopy measurements and by evaporative light scattering detection. Various pressures, temperatures, flow rates and fractions of ethanol as a co-solvent were evaluated. The extractable fraction of carotenoids, chlorophyll A and total lipids were dependent on the co-solvent fraction in the extraction phase. The additional amount that could be extracted by using more co-solvent followed a normal distribution, indicating that analytes should not simply be categorized into weakly or strongly bound. The characteristics of diminishing extraction rates over time was accounted for by analyte partitioning rather than intra-particle diffusion limitations

Vapour Liquid Equilibria Of Monocaprylin Plus Palmitic Acid Or Methyl Stearate At P = (1.20 And 2.50) Kpa By Using Dsc Technique

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The Differential Scanning Calorimetry (DSC) technique is used for measuring isobaric (vapour + liquid) equilibria for two binary mixtures: {monocaprylin + palmitic acid (system 1) or methyl stearate (system 2)} at two different pressures P = (1.20 and 2.50) kPa. The obtained PTx data are correlated by Wilson, NRTL and UNIQUAC models. The original UNIFAC group contribution method is also considered and new binary interaction parameters for the main groups CH2, CCOO, OH and COOH are regressed, to account for the non-idealities found in these lipid systems. Established thermodynamic consistency tests are applied and attest the quality of the measured data. In terms of relevance of the selected components, system 1 can be found in the purification and deodorization steps during the production of edible oils, while, system 2 can be found in the purification steps of biodiesel. It should be noted that no such data could be found in the open literature, not only for the specific components selected but also for the combination of the classes of components considered; that is, acylglycerol plus fatty acid or fatty ester. (C) 2015 Published by Elsevier Ltd.91108115Alfa Laval Copenhagen S/ATechnical University of DenmarkFundação 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 [2013/12735-5