强非共沸工质R1234yf/R170/R14系气液相平衡的模拟

超额吉布斯自由能-状态方程法(G~E-EoS)是继传统的状态方程法和活度系数法之后预测气液相平衡的一个新思路。本文采用PRWS-UNIFAC-PSRK模型对R161/R1234yf、R32/R125/R134a及强非共沸工质R1234yf/R170/R14系的气液相平衡数据进行计算。结果表明:R161/R1234yf系压力和气相组分质量分数的计算值与实验值的偏差在±1.5%和±0.02以内,优于REFPROP9.0软件的计算结果,而R32/R125/R134a系的偏差分别在±4%和±0.02以内。根据计算结果及三维相平衡图发现,R1234yf/R170/R14在质量分数比为0.4/0.2/0.4附近时体系的温度滑移现象最为明显,最大的滑移温度达到72.5 K;且R1234yf组分的质量分数越大,泡点温度与露点温度越高。

Vapor Liquid Equilibria Modeling for Strong Zeotropic Ternary System of R1234yf/R170/R14

The excess Gibbs free energy-equation of state "(" "G" ^"E" "-EoS) " is a new method for predicting the vapor liquid equilibrium (VLE) with respect to the equation of state (EoS) and activity coefficient method. In this study, the Peng Robinson (PR) equation of state was employed in combination with the Wong-Sandler (WS) mixing rule to predict binary and ternary systems coupled with the activity coefficient model: the modified universal quasichemical functional group activity coefficient (UNIFAC) used in the predictive Soave-Redlich-Kwong (PSRK). So a gas-liquid equilibrium prediction model of the mixture (PRWS-UNIFAC-PSRK) was constructed EoS (PRWS-UNIFAC-PSRK model). The to calculated VLE data of R161/R1234yf, R32/R125/R134a, and the strong zeotropic ternary system of R1234yf/R170/R14 were calculated. The results indicated that for R161/R1234yf, the relative deviation of the pressures and the absolute deviation of the vapor phase mass fraction between the experimental and calculated data were within ±1.5% and ±0.02, respectively, which were better than those found using the REFPROP9.0 software, while the deviations for R32/R125/R134a were within ±4% and ±0.02, respectively. The calculated VLE data and three-dimensional phase equilibrium diagrams showed that the temperature glide phenomenon of R1234yf/R170/R14 was the most obvious at the mass fraction ratio of 0.4/0.2/0.4, and the maximum sliding temperature reached 72.5 K. The dew-point and bubble-point temperatures increased with the increase in the mass fraction of R1234yf.