Vapor–Liquid Equilibria of Binary and Ternary Systems Containing Carbon Dioxide, Alkane, and Benzothiophene

Abstract

Experimental vapor–liquid equilibrium (VLE) data of binary and ternary systems are reported covering all of the phase envelopes up to near the critical point. The carbon dioxide + dodecane, carbon dioxide + benzothiophene, and carbon dioxide + nonane + benzothiophene systems were studied at (318.14, 344.75, 373.23, and 417.91) K, 373.93 K, and (313.09, 343.73, and 373.74) K, respectively. The apparatus is based on the static–analytic method with an on-line ROLSI (rapid on-line sampler–injector) sampler to allow fast determination of the VLE. Standard uncertainties for the measured properties in this work were estimated to be p ± 0.01 MPa, T ± 0.03 K, liquid mole fraction xCO2 ± 0.0036, and vapor mole fraction yCO2 ± 0.0016. The experimental VLE data for carbon dioxide + dodecane were found to be in agreement with those available in the literature at 318 K. Furthermore, the corresponding results for the ternary system indicate a high selectivity of nonane in the vapor phase instead of benzothiophene. Data obtained in this work were correlated with the Peng–Robinson equation of state using the Wong–Sandler mixing rules.