Phase equilibrium chemical and

Starting with a combination of the first and second laws we will arrive at a framework of equations which, in combination with the appropriate 

The separation of Chemical and Phase Equilibrium from the general subject of Thermophysical Properties is intended to emphasize the importance of the former. 

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Physical constraints, imposed by mass, energy, and momentum balances, chemical and phase equilibrium conditions, and rate phenomena. 

Sanderson and Chien (18) solve Equations (7), (8), and (13) to determine compositions of vapor and liquid phases in chemical and phase equilibrium given temperature and pressure. A set of independent chemical reactions is selected with guesses for extent of reaction. Solution of Equation (13) leads to compositions in phase equilibrium, but applies only for a vapor and liquid in equilibrium. Residuals of Equations (7) and (8) are computed and extents of reaction, g, and moles of species j, n, are adjusted using Marquardt s method (15). 

Inside the reactive zone, chemical and phase equilibrium occur simultaneously. The composition of phases can be found by Gibbs free-energy minimization. The UNIQUAC model is adopted for phase equilibrium, for which interaction parameters are available, except the binary fatty-ester/water handled by UNIFAC-Dortmund. 

Useful insights into the thermodynamics of a multiphase reacting system can be obtained by analyzing the situation when chemical and phase equilibrium (C PE) are achieved simultaneously. The Gibbs rule can be used to find the degrees of freedom F ... 

In systems where heterogeneous chemical equilibria prevail, both chemical and phase equilibrium conditions must be simultaneously satisfied. In practice, this means that the chemical equilibrium condition—Eq. (51) in the discrete description, and Eq. (60) in the continuous one—must be satisfied in one phase, and the phase equilibrium condition [/( or fi(x) to be the same in all phases] must be satisfied this clearly guarantees that the chemical equilibrium condition is automatically satisfied in all phases. 

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