聚对苯二甲酸乙二醇酯酯化过程组分物性及相平衡计算

Calculations of Physical Properties and Phase Equilibrium in Polyethylene Glycol Terephthalate Esterification System

聚对苯二甲酸乙二醇酯(PET)酯化过程中组分物性和相平衡的准确计算是实现PET工业生产模型化的前提。采用UN IFAC模型,通过再参数化法确定模型的基团交互作用参数,确定了PET酯化过程中组分物性的计算方法———再参数化后的UN IFAC模型。采用再参数化后的UN IFAC模型计算了PET酯化过程中各纯组分的物性(蒸发焓、摩尔定压热容和摩尔体积)、可挥发性二组分物系的汽液平衡数据和对苯二甲酸(PTA)的固液溶解平衡数据。计算值与文献值吻合较好,物性的最大相对误差不超过3%,汽液平衡数据的平均相对误差均小于1%,不同乙二醇含量的乙二醇-对苯二甲酸乙二醇酯混合溶液中PTA饱和含量的计算值与文献值的平均相对误差在0.5%以内,表明该再参数化的UN IFAC模型可准确计算PET酯化多相物系中组分的物性。

Modeling and optimization of industrial continuous polyester process require accurate computation of phase equilibrium and physical properties involved in the polyethylene glycol terephthalate （PET） esterification system. The equation of UNIFAC based on group contribution theory was applied to predict thermodynamic properties and phase equilibrium of the system. The group binary parameters of UNIFAC were re-parameterized through regressing data from China Scientific Databank. The results from UNIFAC model with re-parameterized parameters agreed with those in literature. It was concluded that using the re-parameterized UNIFAC model can satisfactorily predict the vaporliquid-solid equilibrium and physical properties involved in the said esterification system.