Finite Concentration VLE Data

IR Methyl Ethyl Ketone PoCS Methyl Ethyl Ketone 

PDMS Methyl Isobutyl Ketone PS Diethyl Ketone 

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There are no thermodynamic consistency tests that can be applied to the data. For each system in the infinite dilution VLE data base, the weight fraction activity coefficients were plotted as a function of temperature. In many cases considerable scatter was observed. Some data were found that were significantly outside the anticipated range or which showed contradictory behavior with temperature from that expected. These points were kept in the data base but are indicated by an "R", for Rejected, if they were judged to be clearly erroneous or by an "N", for Not recommended, if they appeared questionable but not obviously incorrect. Similarly, in the finite concentration VLE data base some points were judged to be significant outliers and are indicated accordingly. 

This example uses the Chen et al. method to show how experimental results can be compared graphically to model predictions. The file containing experimental data for the polystyrene-ethylbenzene system must first be created using the POLYDATA program. This file contains all the data for this system in the finite concentration VLE data base. The Tutorial for POLYDATA describes how to create this file. 

In the following example finite concentration VLE data for ethylbenzene in polystyrene are extracted from the data bank and saved in the file (PSETHBEN.DAT) that is used in the Tutorial Session for POLYPROG to demonstrate how to import data into that program. 

The selection of a suitable solvent for extractive distillation is roughly guided by the same considerations that influence the selection of solvents for liquid-liquid extraction (see Section 2.2). However, the acquisition of experimental phase equilibrium (VLE) data to obtain phase compositions or finite concentration activity coefficients, in the definition of a selectivity factor for an extractive distillation process, is a time-consuming, tedious and expensive exercise. 

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