Abstract Modeling of vapor-liquid equilibrium for the aqueous solutions of formaldehyde and electrolyte is required for the extractive distillation of formaldehyde-containing multicomponent mixtures using salt as entrainers. Here a revised physicochemical model, which integrates the advantages of the physicochemical model for the vapor-liquid and the chemical equilibria in aqueous formaldehyde solution and the LIFAC model for the phase behavior in mixed-solvent electrolyte systems, has been proposed. The new vapor-liquid equilibrium data in (HCHO–H2O–salt) were systematically measured and utilized to determine newly-introduced model parameters. Comparisons of model calculated and experimental measured values proved that the model presented here provides a reliable method for correlating the vapor-liquid equilibria data in (HCHO–H2O–salt) system. Furthermore, the model established in this work was used to study salts effect on vapor-liquid equilibria. Both the model calculations and the VLE experiments uncover that Zn(NO3)2 is the most promising among all of the entrainers investigated.

中文翻译：

---

模拟甲醛和电解质水溶液的汽液相平衡

摘要 使用盐作为夹带剂萃取蒸馏含甲醛的多组分混合物需要对甲醛和电解质的水溶液进行汽液平衡建模。这里提出了一种改进的理化模型，该模型结合了甲醛水溶液中汽液和化学平衡的物理化学模型和混合溶剂电解质体系中相行为的 LIFAC 模型的优点。(HCHO-H2O-盐) 中新的汽液平衡数据被系统地测量并用于确定新引入的模型参数。模型计算值和实验测量值的比较证明，此处介绍的模型为关联（HCHO-H2O-盐）系统中的气液平衡数据提供了可靠的方法。此外，在这项工作中建立的模型用于研究盐对汽液平衡的影响。模型计算和 VLE 实验都表明 Zn(NO3)2 是所有研究的夹带剂中最有前途的。