Vapor-Liquid Equilibria of Mixtures Containing Nitrogen,Oxygen,Carbon Dioxide,and Ethane

摘要

Vapor-liquid equilibria of binary and ternary mixtures containing nitrogen (N_2) oxygen (O_2) Carbon dioxide (CO_2) and ethane (C_2H_6) are studied by molecular simulation using two-center Lennard-Jones plus point quadrupole models Pure-component models are taken from recent work mixtures are described using teh lorentz-Berthelot combining rules Predictions of vapor-liquid equilibria from pure-componentdata along agree well iwth exsperimental data for eample the azeoropicbehavior of the carbon dioxide + ethane system is predicted correctly Further improvemetns are achieved by adjusting one parameter in the energetic term of th combining rule to binary data For thsi purpose a simple and efficient procedure is proposed Excellent agreement between the molecular models and experimental data for vapor-liquid equilibria satrated densities ad enthalpies of vaporiaationis obgserved for the five binary systems studied inthe present work (N_2+O_2,CO_2+C_2H_6,O_2+CO_2,N_2+CO_2,N_2+C_2H_6).Vapor-liuid equilibria of two ternary mizture (N_2+O_2+CO_2+C)2H_6) are predicted weell without any further adjustmetn of model parameters Results from molecular simulatin are compared to tehose from the Peng-Robinsonequatin of state the PC-SAFT equatin of state and the BACKONE equation of state using the same data to determine model parameters The quality of correlations with system-specific binary interactin parameters from molecular ismulatioand equations of state is similar and the predictive poweofmolecular simulationis clearlysuperior.