C_(8)芳烃体系固液相平衡计算方法与相图

Calculation method and phase diagram of solid-liquid equilibrium for C_(8)aromatics system

介绍了适用于C_(8)芳烃体系固液相平衡计算的3种计算方法,并选取了各方法计算所需的相关参数。利用多组C_(8)芳烃二元和二元以上多元体系固液相平衡文献实验数据,对这3种计算方法进行了偏差比较,结果表明:Van’t Hoff方程简式计算液相摩尔分数与低共熔点温度及组成的偏差均较低;与乙苯有关的二元、三元和四元固液相平衡体系中液相可看作理想溶液。利用Van’t Hoff方程简式计算了由乙苯和其他C_(8)芳烃组成的二元和三元体系的液相摩尔分数、低共熔点温度及组成,并绘制了与乙苯相关的3个三元体系的固液相平衡相图。预测了乙苯-间二甲苯、乙苯-邻二甲苯等二元体系的固液相平衡中液相摩尔分数0~1全范围的数据。

Three calculation methods of solid-liquid equilibrium for C_(8)aromatics system are introduced,and the parameters of each calculation method are selected.Based on the experimental data of solid-liquid equilibria for binary and above binary multicomponent systems of C_(8)aromatics,the deviations of the three methods are compared.The results show that the deviations of liquid phase molar fraction and eutectic point temperature and composition calculated by the simplified Van’t Hoff equation are low,and the liquid phase in binary,ternary and quaternary solid-liquid equilibrium systems related to ethylbenzene can be regarded as ideal solution.The liquid phase molar fraction and eutectic point temperature and composition of binary and ternary systems containing ethylbenzene and other C_(8)aromatics are calculated by the simplified Van’t Hoff equation,three solid-liquid phase equilibrium diagrams of ternary systems(p-xylene-ethylbenzene-m-xylene,o-xylene-ethylbenzene-p-xylene,m-xylene-ethylbenzene-o-xylene)have been drawn.The liquid phase molar fractions of binary systems(ethylbenzene-m-xylene and ethylbenzene-o-xylene)in the whole range from 0 to 1 are predicted.