PR方程结合vdW混合法则推算二元及三元HFC/HC混合工质汽液相平衡性质

Prediction of vapor-liquid equilibria for binary and ternary HFC/HC mixtures using PR equation of state and vdW mixing rule

以PR方程结合vdW混合法则,利用建立的二元相互作用系数kij差值关联模型,对11组二元HFC/HC混合工质及5组三元HFC/HC混合工质(HFC32/HFC125/HFC134a,HC290/HC600a/HFC32,HFC125/HFC143a/HFC134a,HFC32/HC290/HFC227ea,HFC32/HFC125/HC290)汽液相平衡性质进行了推算,并与文献实验数据比较,对压力计算的平均相对偏差分别为2.23%、8.32%、1.43%、0.40%、1.71%,对气相组分计算的平均绝对偏差分别为0.0086、0.0132、0.0054、0.0071、0.0089。结果表明该方法可用于推算二元及三元HFC/HC混合工质汽液相平衡性质。

A method is presented to predict the vapor-liquid equilibria（VLE）for binary and ternary HFC/HC mixtures using PR equation of state and van der Waals（vdW）mixing rule.The binary interaction parameters kij is predicted by the difference-correlation model,which is assumed to be the difference between the mixing factors ki of the pure components.The values of ki for 10 HFCs and 3 HCs are obtained according to VLE correlation for 39 binary mixtures in authors＇ previous works.In this work,this prediction method is further verified with 11 new binary systems（HFC236ea/HC290,HFC152a/HC600,HFC125/HC600a,HFC143a/HC600,HFC227ea/HC600,HFC152/HC290,HFC125/HC227ea,HFC125/HC290,HFC134a/HC290,HFC134/HC290,HFC134/HC600a）,and then extended to predict VLE properties of ternary HFC/HC mixtures,which are HFC32/HFC125/HFC134a,HC290/HC600a/HFC32,HFC125/HFC143a/HFC134a,HFC32/HC290/HFC227ea and HFC32/HFC125/HC290.The predicted results are compared with the experimental data in literature.The overall deviations of pressure and vapor composition are 2.23% and 0.0086 for the HFC32/HFC125/HFC134a system,8.32% and 0.0132 for the HC290/HC600a/HFC32 system,1.43% and 0.0054 for the HFC125/HFC143a/HFC134a system,0.40% and 0.0071 for the HFC32/HC290/HFC227ea system,and 1.71% and 0.0089 for the HFC32/HFC125/HC290 system.The comparison shows very good agreement between predicted and experimental results,validating the feasibility of the method to predict VLE properties for binary and ternary HFC/HC mixtures.