基于COSMO-RS的单工质气液相平衡热物性计算方法

Gas-liquid Equilibrium Calculation of Refrigerant Property based on COSMO-RS

本文对基于真实溶剂似导体模型(COSMO-RS)的单工质制冷剂气液相平衡热物性的模拟精度进行了研究。研究结果表明,调节分子的表面面积比例因子可以改善模型精度。将制冷剂单工质分为无机物、碳氢化合物(HCs)和氢氟烃类化合物(HFCs)3类,在最佳比例因子参数下,模拟值与NIST实验值的相对误差,无机物CO2和NH3分别在±3%和±1%以内,HCs和HFCs在±2%以内。在此基础上,分析各类工质的尺寸因子参数的变化规律,并拟合出各类单工质的饱和蒸气压方程,为新型单工质的气液相平衡热物性预测提供了新方法。

The simulation accuracy of the thermophysical properties of gas-liquid equilibrium of a single refrigerant based on a conductor-like screening model for real solvent(COSMO-RS) is investigated in this work. The research results show that in order to improve the simulation accuracy, the scale factor of the surface area of the molecules needs to be adjusted. A single refrigerant is divided into inorganic substances, hydrocarbons, and HFCs. The simulation results under on optimum scale factor are compared with the values from NIST. The relative errors for CO2 and NH3 in inorganic matters are less than ±3% and ±1%, respectively. The relative error for the hydrocarbon refrigerant is within ±3%, and that for HFCs is not more than ±2%. Then the rule of the scale factor of the molecules is studied and the saturated vapor-pressure equation of a single refrigerant is fitted. Therefore, COSMO-RS can predict the gas-liquid equilibrium of a single refrigerant and provide a method for the gas-liquid equilibrium of new refrigerants.