2. Generic software packages

Generic software packages for calculating phase equilibria of pure substances and mixtures can involve a wide range of fluids, with compositions that vary widely from case to case. This is a highly complex scientific problem that has mobilized many top-level researchers for decades. Fundamental knowledge of the subject is progressing, increasingly comprehensive databases are being published and software packages developed. It is beyond the scope of this article to go into the details of existing options.

Since all these tools require the equation of real fluids, we need to go into this point in greater depth, before discussing and analyzing the precautions to be taken when choosing a model.

Particular emphasis is placed on :

• choice of equations of state ;

• mixing...