盐-水-乙醇-乙二醇体系汽液平衡的预测

电解质溶液汽液平衡的预测和计算是是热力学的一个重要研究领域,是加盐萃取精馏模拟计算的重要基础,精 确的推算电解质溶液的汽液平衡数据有着十分重要的理论和实际意义。本文改进了计算电解质溶液汽液平衡的LI- QUAC模型,用计算水-乙醇-乙二醇体系汽液平衡更为精确的NRTL模型代替lIQUAC模型中的UNIFAC模型来计 算溶剂分子间相互作用对超额Gibbs自由能的影响,并据此推算出两种盐-水-乙醇-乙二醇体系的汽液平衡数据, 与本文实验数据及文献数据比较,结果比较满意。该模型对电解质溶液汽液平衡的进一步研究以及加盐萃取精馏的工 程计算均具有一定的指导意义。

Prediction of vapor-liquid equilibrium for salt-water-ethanol-ethylene glycol systems

The calculation of vapor-liquid equilibrium for mixed-solvent electrolyte systems is important in the research of thermodynamics and the stimulation of extractive distillation with salt. The LIQUAC model is widely used to predict phase equilibrium for electrolyte systems. This work is to have the NRTL modei that can calculate the vapor-liquid equilibrium for water-ethanol-ethylene glycol systems more accurately take the place of UNIFAC modei in the LIQUAC modei to calculate the contribution caused by interactions of solvent molecule, to the excess Gibbs energy, and thua provide a modified LIQUAC model based on the LIQUAC modei that can be well used in a lager number of electrolyte systems. The modified model has been used to calculate the vapor-liquid equilibrium behavior for two kinds of salt-water-ethanol-ethylene glycol systems with high accuracy. It has certain sense for further study and application to the simulation of extractive distillation with salt.