Vapor plus liquid equilibrium of water, carbon dioxide, and the binary system, water plus carbon dioxide, from molecular simulation

NVT- and NpT-Gibbs ensemble Monte Carlo (GEMC) simulations were applied to describe the vapor-liquid equilibrium of water (between 323 and 573 K), car bon dioxide (between 230 and 290 K) and their binary mixtures (between 348 and 393 K). The properties of supercritical carbon dioxide were determined between 310 and 520 K by NpT-MC simulations. Literature data for the effect ive pair potentials (for water: the SPC-, SPC/E-, and TIP4P potential model s; for carbon dioxide: the EPM2 potential model) were used to describe the properties of the pure substances. The vapor pressures of water and carbon dioxide are calculated. For water, the SPC- and TIP4P models give superior results for the vapor pressure when compared to the SPC/E model. The vapor- liquid equilibrium of the binary mixture, carbon dioxide-water, was predict ed using the SPC- as well as the TIP4P model for water and the EPM2 model f or carbon dioxide. The interactions between carbon dioxide and water were e stimated from the pair potentials of the pure components using common mixin g rules without any adjustable binary parameter. Agreement of the predicted data for the compositions of the coexisting phases in vapor-liquid equilib rium and experimental results is observed within the statistical uncertaint ies of the simulation results in the investigated range of state, i.e. at p ressures up to about 20 MPa, (C) 2000 Elsevier Science B,V, All rights rese rved.