Phase equilibrium of propane and alkanes: Part I. Experimental procedures, dotriacontane equilibrium and EOS modelling

In order to study the equilibria of long-chain alkanes and supercritical fluids, a high-pressure phase equilibrium cell has been designed, constructed, commissioned and tested against reliable literature data. Phase equilibrium data for propane-dotriacontane (nC32H66) have been measured between 378.2 and 408.2 K. Emphasis was placed on measuring equilibrium data in the mixture critical region. Ten cubic and five non-cubic equations of state have been applied to the phase equilibrium data at 408.2 K. The modified Patel–Teja (MPT), as a cubic EOS, and statistical associating fluid theory (SAFT), as a non-cubic EOS, give the best-fit of the data at 408.2 K. The phase equilibrium predictions of the SAFT EOS significantly deteriorated as the critical point of the solvent was approached.