Vapor–Liquid Equilibrium Measurement for Carbon Dioxide (CO2) + 2,3,3,3-Tetrafluoropropylene (R1234yf) Binary Mixtures

Abstract

CO₂-based binary mixtures offer superior thermodynamic advantages and environmental benefits compared to alternative working fluids. Enthalpy and entropy are essential in thermodynamic analysis, necessitating the availability of vapor–liquid equilibrium data. The static thermostatic analysis system accurately measures the mixtures’ temperature, pressure, and molar fractions. We carry out five temperatures at 283.15 K to 323.15 K while maintaining a pressure of approximately 6.38 MPa. Two electromagnetic capillary samplers effectively extract working fluids from the equilibrium cell, facilitating precise analysis using a gas chromatograph. The standard measurement uncertainties of experimental temperature, mole fractions, and pressure are determined at 0.06 K, 0.004, and 0.002 MPa, ensuring precise and reliable data for our analysis. The experimental data we gathered has undergone extensive analysis and modeling using the PR + WS + NRTL model to offer a comprehensive insight into the system's behavior. The AARDp value is 0.81%, whereas AADy₁ demonstrates merely a slight variance of 0.0047. The relative volatility is determined at five temperatures ranging from 283.15 K to 323.15 K. The majority of the experimental data falls within the ± 5% deviation boundary, affirming their reliability.