Validation of Thermodynamic Models

In a nonideal system such as ethyl acetate/water/ ethanol, for instance, there exists considerable complexity from a phase equilibrium point of view because of the presence of a liquid liquid-equilibrium (LLE) envelope, as well as the presence of three binary azeotropes and a single ternary azeotrope. Attempts have been made to 

FIGURE 4.11 Superimposed RCMs for the ethyl acetate/water/ethanol stem using the NRTL and UNIQUAC phase equilibrium models at a pressure of 0.825 atm. Shaded LLE region also shown. 

A simple alternative to the problem is to use our knowledge of CPMs to shift the appropriate nodes away from the LLE region. Once these nodes have been shifted satisfactorily, one can simply measure these profiles using the techniques described in Sections 4.2 and 4.3. Such a case where nodes have been shifted is shown in figure 4.12 where finite reflux profiles have been constructed such that 

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