MOLECULAR MODELING IN THE SEARCH OF IMPROVED EQUATION OF STATE

In the search of improved EOS the results of molecular theory and comp uter simulations are extensively used, special attention being paid to effects of molecular size, polarity and the ability of molecules to a ssociate. The relation of various EOS to underlying molecular models i s discussed, the advantages of the SAFT EOS as the most theoretically sound equation are emphasized. New results are presented concerning th e application and modification of the hole group contribution model pr oposed in our previous works. This model has proved to be universal an d sufficiently elaborated for phase equilibria calculations over a wid e range of temperatures and pressures for pure and mixed fluids of dif ferent chemical nature. However a simultaneous accurate description of single phase regions and of saturation curves using this model or oth er classical EOS is a problem.