Phase Behavior for the Carbon Dioxide + 2-Butanol System: Experimental Measurements and Modeling with Cubic Equations of State

Abstract

Vapor-liquid equilibria (VLE) data for the carbon dioxide + 2-butanol system at (298.15, 303.15, 308.15, 313.15, and 318.15) K up to 81.5 bar are reported. The experimental method used in this work was a static-analytical method with liquid and vapor phase sampling. The new experimental results are discussed and compared with available literature data. Measured VLE data and literature data for the carbon dioxide + 2-butanol system were modeled with a general cubic equation of state (GEOS), Peng-Robinson (PR) equation of state (EoS), and Soave-Redlich-Kwong (SRK) EoS using classical van der Waals (two-parameter conventional mixing rule, 2PCMR) mixing rules. A single set of interaction parameters for each equation of state, representing exactly the experimental critical pressure maximum (CPM) and the experimental temperature of the upper critical end point (UCEP), was used to calculate the phase behavior in the binary mixture carbon dioxide + 2-butanol in a wide range of temperatures [(278.21 to 512.3) K]. The GEOS equation is more reliable for predicting the critical curve and the bubble-point lines, and it is less exact for predicting the gas phase composition at higher temperatures.