Measurement and Modeling of High Pressure Vapor-liquid Equilibria of Co2 + Alcohol Binary Systems

A new apparatus based on a static-analytic method was developed in this work to perform high-pressure vapor-liquid equilibria measurements up to 68 MPa and 373 K. In order to validate this new apparatus, vapor-liquid equilibria of the binary system CO2 + ethanol was measured at temperatures of 313, 323 and 338 K and pressures from 1.2 to 11 MPa. Results were compared with data from the literature, differences for the mol fractions of liquid and vapor phases were ≤3%. Vapor-liquid equilibria for the binary systems CO2 + 1-propanol, CO2 + 2-methyl-1-propanol, CO2 + 3-methyl-1-butanol and CO2 + 1-pentanol at 313 K, 323 K and 333 K, and pressures in the range of 2-12 MPa was measured and modeled with the Peng-Robinson equation of state with the quadratic mixing rules of van der Waals with two adjustable parameters. The results shown that the average absolute deviations for the mol fractions were lower than 7% and 2% for the liquid and vapor phase, respectively.