Fluid Phase Equilibria in Quasi‐Binary Systems of Ethylene + n‐Eicosane + n‐Tetracontane

Abstract Vapour‐liquid equilibria in quasi‐binary systems of ethylene with mixtures of n‐eisosane and n‐tetracontane of fixed molar ratios of n‐eisosane to n‐tetracontane of 0.748:0.252, 0.700:0.300, 0.510:0.490 and 0.247:0.753 have been measured in the temperature range 325 to 450 K and at pressures up to 40 MPa. The results show a distinct influence of the mean molecular weight of the n‐alkane mixtures on these equilibria especially in the critical region. The phase behaviour of the quasi‐binary systems investigated is compared with the phase behaviour of binary systems of ethylene and n‐alkanes. — It is shown that except for the high‐pressure region the fluid phase equilibria of the quasi‐binary systems can be predicted reasonably well with the Peng‐Robinson equation of state using only pure component and binary data to determine the adjustable parameters.