二氯甲烷-甲醇-丙酮-水体系汽液平衡测定和关联

二氯甲烷-甲醇-丙酮-水四元体系常见于化工、医药等行业生产的废液中,该体系分离回收的前提是进行汽液平衡数据的测定。现利用单级循环汽液平衡釜测定了二氯甲烷、甲醇、丙酮、水混合液中的6组二元体系在常压下的汽液平衡数据,同时对其进行了点对点法热力学一致性校验。实验中采用SP-6800型气相色谱仪分析汽液相组成,并运用Matlab中的非线性最小二乘法分别关联6组二元体系的汽液相组成,从而得到6对Wilson模型参数,并计算出相应的汽相组成。此外,还测定了二氯甲烷-甲醇-丙酮-水四元体系在100 kPa下的汽液平衡数据,并用关联出的6对模型参数计算该四元体系的汽液平衡数据。将计算结果与实验结果进行对比,实验值与计算值间的绝对偏差均小于0.05。实验结果表明Wilson模型的拟合精度高,适合于关联二氯甲烷、甲醇、丙酮、水体系。实验和计算结果为萃取精馏分离二氯甲烷、甲醇、丙酮、水混合液提供了一定的基础数据。

Measurement and correlation of vapor-liquid equilibria for dichloromethane-methanol-acetone-water system

In the chemical and medicine industry,the dichloromethane-methanol-acetone-water quaternary system is commonly existed in the liquid waste.It is essential of the vapor-liquid equilibrium(VLE) data for this system to recover them by separating process.Isobaric VLE data on the six pairs of binary mixtures of dichloromethane,methanol,acetone and water were determined with single stage vapor-liquid equilibrium still at atmospheric pressure.The result shows that the thermodynamic consistency of the experimental data is satisfied by means of point to point method.In the experiment,the vapor-liquid phase compositions were analyzed by using SP-6800 gas chromatograph.Six pairs of correlation parameters of Wilson model and the calculated values of vapor-phase compositions were observed by using non-linear least square method procedure of Matlab.Besides,the vapor-liquid equilibria in this quaternary system were measured experimentally at 100 kPa,correlated by the six pairs of model parameters,and compared with the experimental data.The results obtained show that the absolute deviation of experiment and calculation is less than 0.05.It means that the Wilson model is reliable for the prediction and correlation of the VLE data of the dichloromethane-methanol-acetone-water quaternary system as to its exact fitting accuracy.The experimental and correlative data can provide a basis for extractive distillation separation of dichloromethane-methanol-acetone-water system.