High-Pressure Phase Behavior of CO{sub}2 + Polyethylene Glycol + Ethanol System at Pressures up to 20 MPa

摘要

Phase equilibria for carbon dioxide (CO{sub}2) + poly(ethylene glycol) (PEG1000, PEG6000, PEG20000) + ethanol mixtures were measured at pressures up to 20 MPa. Furthermore, the cloud point temperature of PEG in ethanol was determined at atmospheric pressure. To determine the phase boundary, we observed the cloud point using a variable volume view cell. With regard to the liquid-liquid phase boundaries of CO{sub}2 + PEG + ethanol systems, the one-phase region increased with increasing pressure and decreasing molecular weight of PEG. The Sanchez-Lacombe equation of state was used to correlate the phase behavior of these systems.