Improvement of predictive tools for vapor-liquid equilibrium based on group contribution methods applied to lipid technology

Abstract

Predictive methodologies based on group contribution methods, such as UNIFAC, play a very important role in the design, analysis and optimization of separation processes found in oils, fats and biodiesel industries. However, the UNIFAC model has well-known limitations for complex molecular structures that the first-order functional groups are unable to handle. In the particular case of fatty systems these models are not able to adequately predict the non-ideality in the liquid phase. Consequently, a new set of functional groups is proposed to represent the lipid compounds, requiring thereby, new group interaction parameters. In this work, the performance of several UNIFAC variants, the Original-UNIFAC, the Linear-UNIFAC, Modified-UNIFAC and the Dortmund-UNIFAC is compared. The same set of experimental data and the parameter estimation method developed by Perederic et al. (2017) have been used.

Vapor–Liquid Equilibria of Binary Systems with Long-Chain Organic Compounds (Fatty Alcohol, Fatty Ester, Acylglycerol, and n-Paraffin) at Subatmospheric Pressures

“…The UNIQUAC model for liquid phase () and vapor phase (-•-). Predictions for liquid phase of the Modified UNIFAC with its lipid-based parameters (•••), and of the NIST modified UNIFAC (-••-).…”

“…Predictive capacity of the Linear, Modified, and Dortmund UNIFAC methods with their original parameters − and with the lipid-based parameters and of the NIST modified UNIFAC were evaluated. Predicted values of boiling temperatures with their respective deviations (AAD and ARD) are given in Supporting Information Tables S2 and S3.…”

“…More recently, Damaceno et al improved predictive tools for vapor–liquid equilibria based on group contribution methods (UNIFAC) involving lipid compounds. New matrixes for the Linear UNIFAC, Modified UNIFAC, and Dortmund UNIFAC were presented, and their performances in prediction were compared with the original parameters.…”

“…Considering its adequacy to high cost and thermal sensitive compounds, the DSC technique was selected. − Vapor pressure data for dinonanoin was modeled using the Antoine equation. TPx data were correlated using the gamma-phi approach (considering vapor phase as ideal) after checking their thermodynamic consistency using the pure component consistency test. ,, Activity coefficients were modeled using the UNIFAC method and different versions of the UNIFAC method: the Linear UNIFAC, the Modified UNIFAC and the Dortmund UNIFAC with both their original parameters ( a mn ) and the lipid-based parameters regressed by Damaceno et al, and also with the NIST modified UNIFAC . For comparison purposes, Raoult’s law was also applied.…”

Process Analysis of Shea Butter Solvent Fractionation Using a Generic Systematic Approach

“…Original, 2 Linear, Lyngby Modified and Dortmund Modified 10 ) allowing the estimation of properties for a wide range of mixtures for this class of compounds. The currently available thermodynamic models for pure compounds 4,11,12 and mixtures 2,10 are included in the Lipids Database, that can be used within different PSE domains 2 .…”