二元系多甘醇水溶液的混合热与汽液平衡关系的研究

Investigation of Relationship Between Heat of Mixing aud Vapor-Liquid Equilibrium for Binary Aqueous Solutions of Glycols

使用Calvet BT2.15型低温微量热计测定了二甘醇、三甘醇分别与水的二元体系在298.15,308.15和318.15K温度下的混合热(△H或H^E)。基于此实测的△H～f(x,T)数据和甘醇水溶液在298.15和319.15K温度下的文献值,进行了△H的关联与VLE的推算,采用的工作方程是在评比了几个基于局部组成概念的半经验模型后,对溶液理论模型加以修正提出的,将改进后的模型与广为流行的三参数NRTL模型比较,其关联与推算的结果是令人满意的,尤其是对VLB的推算显著优于3-NRTL方程。

The heat of mixing (△H or H^E) for two binary systems. diethyleneglycol-water and triethylene glycol-water, were measured over a wide range of composi-tions and at three temperatures, 298.15, 308.15 and 318.15 K respectively. Themeasurements were carried out in a Calvet low-temperature microcalorimeter. All themeasured and literature data for the binary systems are used to predict their vapor-liquidequilibria (VLE). Based on solution thermodynamics and evaluation of currently popularlocal composition models, new working equations were derived in this work, which is amodified version for the NRTL model. A comparison of the original NRTL equation withour new equations shows that with satisfactory predictions of VLE from the head of mixing,the proposed equations are an improvement over the NRTL model.