硫酸锂-乙醇-水体系在高原大气压下的气-液平衡研究

盐-混合溶剂体系气-液平衡研究具有重要的理论和实用意义。盐加到互溶双液系能改变组分间相对挥发度,提高蒸馏效率,分离恒沸物。达面方工作,Furter已作过详细综述。从盐-混合溶剂体系气-液平衡研究可以计算离子的溶剂化数,探索离子-溶剂和溶剂-溶剂之间的相互作用。因此,盐-混合溶剂体系气-液平衡的研究目前在国内外越来越受到人们的重视。本文研究盐饱和下的硫酸鲤-乙醇-水体系在高原大气压(530 Torr左右)下的汽-液平衡。改进的Rose釜测定体系的p-T-x-y数据。按照Jaques的假二元体系模型,使用Wilson,NRTL和修正的UNIQUAC方程关联实验数据。在计算过程中,使用一个能在计算机上顺利得到结果的计算方法。

A STUDY OF VAPOR-LIQUID EQUILIBRIUM FOR THE TERNARY SYSTEM Li2SO4-C2H5OH-H2O AT PLATEAU ATOMSPHERE

In this paper, a lernary system of Li_2SO_4-C_2H_5OH-H_2O, saturated with salt, was studied. The modified Rose still was utilized to measure the p-T-x-y data for the system at plateau atmosphere (580 Torr or so). According to the Jaques and Furter's pseudo-binary system model, Wilson, NRTL and modified UNIQAC equations were used to correlate with the vapor-liquid equilibrium data. In the calculation, temperature was varied from low to high with steps of 0.01 ℃, and the formulas of |y_1+y_2-1|<10~(-4) or y_1+y_2-1>0 was used for judging the end of the calculation. The method can save the time for computation. The calculated results fit with experimental data, and the maximal deviations of y and T for the modified Uniquac equation are 0.025 molar fraction and 0.23 ℃. In this system, the solubility of lithium sulfate decreases rapidly with the increase of the concentration of alcohol. It means ethanol has a very hight salt-out capacity for lithium sulfate.