SGTPy.equilibrium

Phase equilibrium conditions are obtained from a differential entropy balance of a multiphase system. The following equations must be solved:

\[\begin{split}T^\alpha = T^\beta = ... &= T^\pi\\ P^\alpha = P^\beta = ... &= P^\pi\\ \mu_i^\alpha = \mu_i^\beta = ... &= \mu_i^\pi \quad i = 1,...,c\end{split}\]

Where \(T\), \(P\) and \(\mu\) are the temperature, pressure and chemical potential. When working with EoS usually equilibrium is guaranteed by fugacity coefficients:

\[x_i^\alpha\hat{\phi}_i^\alpha = x_i^\beta \hat{\phi}_i^\beta = ... = x_i^\pi \hat{\phi}_i^\pi \quad i = 1,...,c\]

Usual equilibrium calculations include vapor-liquid equilibrium (flash, bubble point, dew point), liquid-liquid equilibrium (flash and stability test) and vapor-liquid-liquid equilibrium (multiflash and stability test). Those algorithms are described in the following sections:

• Two phase Flash
• Vapor liquid equilibrium
• Multiphase Flash
• Stability