New apparatus for the fast determination of high-pressure vapor-liquid equilibria of mixtures and of accurate critical pressures

An apparatus based on the static-analytic method has been designed to perfo rm fast determinations of vapor-liquid equilibria and critical pressures fo r mixtures up to 60 MPa and 523 K. Vapor pressures of isobutane and vapor-l iquid equilibria of the following mixtures-carbon dioxide + ethanol at (312 .82, 313.15, 333.82, 333.75, 348.4, and 373.00) K up to 14.3 MPa and carbon dioxide + 2-propanol at (324.99, 324.70, 333.70, 333.82, and 348.65) K up to 10.5 MPa-are reported herein over the whole range of compositions. The e xperimental data are represented/predicted using the Patel-Teja equation of state (EOS) with new Wong-Sandler type mixing rules. For the carbon dioxid e + ethanol and carbon dioxide + 2-propanol mixtures, the parameters of the EOS were fitted to the VLE data at 313.15 K and at 324.70 K, respectively. VLE data at higher temperatures were then predicted and found to be in goo d agreement with the data reported in this work. Critical pressures and com positions were also determined for the system carbon dioxide + ethanol at 3 12.82, 333.75, 333.82, 348.40, and 373.00 K; all of them are in agreement w ith those published in the literature.