Vapor-liquid equilibria ef the binary system HFC134a/HCFC133a

Eighteen values of the bubble-point and dew-point temperature, pressure, an d molar volume for the binary HFC 134a/HCFC133a system were measured with a constant-volume method. The saturated points were observed with a transpar ent sample cell inside a thermostatic bath. The experimental results for th e variable compositions cover the temperature range of 300-360 K,. correspo nding to the pressure range of 0.2909-2.6393 MPa. The experimental uncertai nties of temperature and pressure are estimated to be no greater than +/-10 mK and +/-3.4 kPa; the maximum and minimum uncertainties of molar volume a re 3.63% and 0.043%, respectively. The binary interaction constants k(ij) o f the Peng-Robinson (PR) equation and the Lee-Kesler-Plocker (LKP) equation were determined with the experimental data on the basis of the present mea surements. The binary interaction constant k(ij) of the PR equation is 0.01 3, and the maximum saturated pressure calculation deviation is 0.71%. When bubble-point and dew-point properties mere estimated using the LKP equation , the interaction constants k(ij) are 0.9933 and 0.9942, respectively, and the maximum saturated pressure calculation deviations are 0.61% and 0.89%, respectively. Using the PR and LKP equations with the corresponding estimat ed k(ij) values, the deviations of calculating the saturated temperature ar e +/-0.2 K and +/-1 K, respectively. The calculation results of vapor-liqui d equilibrium properties based on the PR equation of state are also present ed.