Abstract:

In this work, volume translation Soave-Redlich-Kwong (VTSRK) equation of state was applied to 2,3,3,3-tetrafluoroprop-1-ene (R1234yf), trans-1,3,3,3-tetrafluoro-1-prpene (R1234ze(E)), and their binary mixtures with CO₂.A temperature-dependent volume translation term was utilized to improve high density region representation.van der Waals mixing rules was applied for mixture representation.The binary interaction coefficient was regressed from literature experiment pressure-volume-temperature-component (pvTx) data.For the pure substances, single phase densities, vapor pressure, and saturated vapor and liquid densities were compared with reference equations of state (EOS).For R1234yf, vapor phase density relative root mean square deviation (RMSD) of the calculations from reference EOS was 0.74%, liquid phase density relative RMSD was 2.86%, saturation pressure relative RMSD was 1.20%, saturation vapor density relative RMSD was 2.51%, and saturation liquid density relative RMSD was 1.05%; while for R1234ze(E), vapor phase density relative RMSD was 0.59%, liquid phase density relative RMSD was 2.48%, vapor pressure relative RMSD was 1.14%, saturation vapor density relative RMSD was 2.37%, and saturation liquid density relative RMSD was 0.63%.Compared with the original Soave-Redlich-Kwong (SRK) equation of state, the VTSRK equation of state significantly improved the density representation in the liquid region and the saturation liquid line.For mixture density calculation, the equation was compared with literature experimental pvTx data in the vapor phase.For the binary mixture of R1234yf+CO₂, the relative RMS was 1.17%; for the binary mixture of R1234ze(E)+CO₂, the relative RMS was 0.82%.The result was much better than the original SRK EOS.The result showed that the VTSRK equation of state with the temperature-dependent volume translation term was accurate within 3% for the density representation of pure substances R1234yf and R1234ze(E), as well as of the binary mixture of R1234yf+CO₂ and R1234ze(E)+CO₂.

Key words: thermodynamic properties, binary mixture, carbon dioxide, equation of state, phase equilibria

摘要：

采用温度相关比容平移项的比容平移Soave-Redlich-Kwong（VTSRK）方程计算新工质R1234yf和R1234ze（E）的热力学性质以及两种物质与CO₂的二元混合物性质，混合物计算采用van der Waals混合规则，二元交互作用系数由密度数据拟合得到。对纯净物计算与专用状态方程进行对比，VTSRK方程比SRK方程显著改善了液相密度表征效果。对混合物的密度计算结果与实验数据进行对比，对于R1234yf+CO₂二元混合体系方程与实验数据相对均方根偏差为1.17%，对于R1234ze（E）+CO₂二元混合体系相对均方根偏差为0.82%。结果显示，采用温度相关比容平移项的VTSRK方程应用于R1234yf和R1234ze（E）纯流体以及R1234yf+CO₂和R1234ze（E）+CO₂密度性质计算，可获得较高精度。

关键词: 热力学性质, 二元混合物, 二氧化碳, 状态方程, 相平衡